In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
IntheLinuxkernel,thefollowingvulnerabilityhasbeenresolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt >start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can tbe moved to it spreviousplace since we re dropping ->tree_lock and it can cause arace conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt >start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it spossible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere sno real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt> start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, createa file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() cant be moved to its previousplace since we re dropping ->tree_lock and it can causea race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt> start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if its possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even iftheres no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateIbelieve there are some issuesintroduced by commit 31651c607151( hfsplus:avoid deadlockon file truncation )HFS+ has extent records which always contains 8extents. Incasethefirst extent record in catalog file gets full,new ones are allocatedfromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, thelogic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guardedanymore.Right action wouldbe just freeing the extents that exceedthe new sizeinside extent recordby calling hfsplus_free_extents(), and then check ifthe whole extent record should beremoved. However since the guard(blk_cnt > start)is now after the call to hfs_brec_remove(), this hasunfortunateeffect that the last matching extent record is removedunconditionally.To reproduce this issue, create afile which has atleast 10extents, andthen perform shrinking truncate into middle of the last extent record, sothat thenumber ofremaining extents is not under ordivisibleby 8. Thiscauses the last extent record (8 extents) to be removedtotally instead oftruncating intomiddle of it. Thus this causes corruption, and lostdata.Fix for this is simply checking if thenew truncated end is below thestart of thisextent record, making it safe toremove the full extentrecord. Howevercallto hfs_brec_remove() can t be moved to it s previousplacesince we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the nodedata.Another issueis related to this one. Whenentering into the block(blk_cnt >start) we are not holdingthe->tree_lock. We break out fromthe loop not holding the lock, buthfs_find_exit() does unlock it. Notsure if it s possible for someoneelse to take the lock under our feet,but it can cause hard todebug errorsand premature unlocking. Even ifthere s no realrisk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
IntheLinuxkernel,thefollowingvulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believethere are some issues introduced bycommit 31651c607151( hfsplus:avoid deadlock on file truncation )HFS+ hasextent recordswhich always contains 8 extents. In case thefirst extent record incatalog filegetsfull, new ones are allocated fromextents overflowfile.In case shrinkingtruncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschangedso that call to hfs_brec_remove() is not guarded any more.Right action would be just freeingtheextents that exceed thenew sizeinside extent record by callinghfsplus_free_extents(), and thencheck ifthe whole extent record should be removed. However since the guard(blk_cnt >start) isnow after the call to hfs_brec_remove(),this hasunfortunate effect that the last matching extent recordis removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthenperform shrinkingtruncateinto middle of the last extent record, sothat the number of remaining extents is not under ordivisibleby 8. Thiscauses the last extentrecord (8extents) to be removed totally instead oftruncating into middle ofit. Thus this causes corruption,andlost data.Fix for this issimply checking if thenew truncated end is below thestart of thisextent record, making it safe to remove thefull extentrecord. However callto hfs_brec_remove() can t bemoved toit spreviousplace since we re dropping ->tree_lock and it cancause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering intothe block(blk_cnt > start) weare not holding the ->tree_lock. We break out fromthe loopnotholding the lock, but hfs_find_exit() does unlock it. Notsure ifit s possible for someone else to take the lock under our feet,but itcan cause hard to debug errors and premature unlocking. Evenifthere s noreal risk of it, the locking should still alwaysbe kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
In the Linux kernel, the following vulnerability has been resolved:hfsplus: prevent corruption in shrinking truncateI believe there are some issues introduced by commit 31651c607151( hfsplus: avoid deadlock on file truncation )HFS+ has extent records which always contains 8 extents. In case thefirst extent record in catalog file gets full, new ones are allocated fromextents overflow file.In case shrinking truncate happens to middle of an extent record whichlocates in extents overflow file, the logic in hfsplus_file_truncate() waschanged so that call to hfs_brec_remove() is not guarded any more.Right action would be just freeing the extents that exceed the new sizeinside extent record by calling hfsplus_free_extents(), and then check ifthe whole extent record should be removed. However since the guard(blk_cnt > start) is now after the call to hfs_brec_remove(), this hasunfortunate effect that the last matching extent record is removedunconditionally.To reproduce this issue, create a file which has at least 10 extents, andthen perform shrinking truncate into middle of the last extent record, sothat the number of remaining extents is not under or divisible by 8. Thiscauses the last extent record (8 extents) to be removed totally instead oftruncating into middle of it. Thus this causes corruption, and lost data.Fix for this is simply checking if the new truncated end is below thestart of this extent record, making it safe to remove the full extentrecord. However call to hfs_brec_remove() can t be moved to it s previousplace since we re dropping ->tree_lock and it can cause a race conditionand the cached info being invalidated possibly corrupting the node data.Another issue is related to this one. When entering into the block(blk_cnt > start) we are not holding the ->tree_lock. We break out fromthe loop not holding the lock, but hfs_find_exit() does unlock it. Notsure if it s possible for someone else to take the lock under our feet,but it can cause hard to debug errors and premature unlocking. Even ifthere s no real risk of it, the locking should still always be kept inbalance. Thus taking the lock now just before the check.
