From 536d4ac8ad16e8e1d0885ca23f11bd5c46972be2 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Mon, 28 Oct 2024 08:11:13 +0000 Subject: [PATCH 1/3] nilfs2: fix potential null-ptr-deref in nilfs_btree_insert() stable inclusion from stable-v5.10.227 commit 24bf40740a3da6b4056721da34997ae6938f3da1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPKK CVE: CVE-2024-47699 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24bf40740a3da6b4056721da34997ae6938f3da1 ------------------------------------------------- [ Upstream commit 9403001ad65ae4f4c5de368bdda3a0636b51d51a ] Patch series "nilfs2: fix potential issues with empty b-tree nodes". This series addresses three potential issues with empty b-tree nodes that can occur with corrupted filesystem images, including one recently discovered by syzbot. This patch (of 3): If a b-tree is broken on the device, and the b-tree height is greater than 2 (the level of the root node is greater than 1) even if the number of child nodes of the b-tree root is 0, a NULL pointer dereference occurs in nilfs_btree_prepare_insert(), which is called from nilfs_btree_insert(). This is because, when the number of child nodes of the b-tree root is 0, nilfs_btree_do_lookup() does not set the block buffer head in any of path[x].bp_bh, leaving it as the initial value of NULL, but if the level of the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(), which accesses the buffer memory of path[x].bp_bh, is called. Fix this issue by adding a check to nilfs_btree_root_broken(), which performs sanity checks when reading the root node from the device, to detect this inconsistency. Thanks to Lizhi Xu for trying to solve the bug and clarifying the cause early on. Link: https://lkml.kernel.org/r/20240904081401.16682-1-konishi.ryusuke@gmail.com Link: https://lkml.kernel.org/r/20240902084101.138971-1-lizhi.xu@windriver.com Link: https://lkml.kernel.org/r/20240904081401.16682-2-konishi.ryusuke@gmail.com Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping") Signed-off-by: Ryusuke Konishi Reported-by: syzbot+9bff4c7b992038a7409f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9bff4c7b992038a7409f Cc: Lizhi Xu Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin Signed-off-by: Zhang Kunbo --- fs/nilfs2/btree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c index a426e4e2acda..c2aca9cd7864 100644 --- a/fs/nilfs2/btree.c +++ b/fs/nilfs2/btree.c @@ -381,7 +381,8 @@ static int nilfs_btree_root_broken(const struct nilfs_btree_node *node, if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN || level >= NILFS_BTREE_LEVEL_MAX || nchildren < 0 || - nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) { + nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX || + (nchildren == 0 && level > NILFS_BTREE_LEVEL_NODE_MIN))) { nilfs_crit(inode->i_sb, "bad btree root (ino=%lu): level = %d, flags = 0x%x, nchildren = %d", inode->i_ino, level, flags, nchildren); -- Gitee From 87acc72a47232a5c6f660b14b5cc22246c9afc10 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Mon, 28 Oct 2024 08:11:14 +0000 Subject: [PATCH 2/3] nilfs2: determine empty node blocks as corrupted stable inclusion from stable-v5.10.227 commit e2290906bb24a57872e9f926693e49cb01e7b8a6 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPKK CVE: CVE-2024-47699 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e2290906bb24a57872e9f926693e49cb01e7b8a6 ------------------------------------------------- [ Upstream commit 111b812d3662f3a1b831d19208f83aa711583fe6 ] Due to the nature of b-trees, nilfs2 itself and admin tools such as mkfs.nilfs2 will never create an intermediate b-tree node block with 0 child nodes, nor will they delete (key, pointer)-entries that would result in such a state. However, it is possible that a b-tree node block is corrupted on the backing device and is read with 0 child nodes. Because operation is not guaranteed if the number of child nodes is 0 for intermediate node blocks other than the root node, modify nilfs_btree_node_broken(), which performs sanity checks when reading a b-tree node block, so that such cases will be judged as metadata corruption. Link: https://lkml.kernel.org/r/20240904081401.16682-3-konishi.ryusuke@gmail.com Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping") Signed-off-by: Ryusuke Konishi Cc: Lizhi Xu Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin Signed-off-by: Zhang Kunbo --- fs/nilfs2/btree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c index c2aca9cd7864..7cfff27b4b4a 100644 --- a/fs/nilfs2/btree.c +++ b/fs/nilfs2/btree.c @@ -350,7 +350,7 @@ static int nilfs_btree_node_broken(const struct nilfs_btree_node *node, if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN || level >= NILFS_BTREE_LEVEL_MAX || (flags & NILFS_BTREE_NODE_ROOT) || - nchildren < 0 || + nchildren <= 0 || nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) { nilfs_crit(inode->i_sb, "bad btree node (ino=%lu, blocknr=%llu): level = %d, flags = 0x%x, nchildren = %d", -- Gitee From 6df15fd2dfdf04a125928d432a939473e91bb7c2 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Mon, 28 Oct 2024 08:11:15 +0000 Subject: [PATCH 3/3] nilfs2: fix potential oob read in nilfs_btree_check_delete() stable inclusion from stable-v5.10.227 commit d20674f31626e0596ae4c1d9401dfb6739b81b58 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPKK CVE: CVE-2024-47699 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d20674f31626e0596ae4c1d9401dfb6739b81b58 ------------------------------------------------- [ Upstream commit f9c96351aa6718b42a9f42eaf7adce0356bdb5e8 ] The function nilfs_btree_check_delete(), which checks whether degeneration to direct mapping occurs before deleting a b-tree entry, causes memory access outside the block buffer when retrieving the maximum key if the root node has no entries. This does not usually happen because b-tree mappings with 0 child nodes are never created by mkfs.nilfs2 or nilfs2 itself. However, it can happen if the b-tree root node read from a device is configured that way, so fix this potential issue by adding a check for that case. Link: https://lkml.kernel.org/r/20240904081401.16682-4-konishi.ryusuke@gmail.com Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping") Signed-off-by: Ryusuke Konishi Cc: Lizhi Xu Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin Signed-off-by: Zhang Kunbo --- fs/nilfs2/btree.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c index 7cfff27b4b4a..7c9f4d79bdbc 100644 --- a/fs/nilfs2/btree.c +++ b/fs/nilfs2/btree.c @@ -1660,13 +1660,16 @@ static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key) int nchildren, ret; root = nilfs_btree_get_root(btree); + nchildren = nilfs_btree_node_get_nchildren(root); + if (unlikely(nchildren == 0)) + return 0; + switch (nilfs_btree_height(btree)) { case 2: bh = NULL; node = root; break; case 3: - nchildren = nilfs_btree_node_get_nchildren(root); if (nchildren > 1) return 0; ptr = nilfs_btree_node_get_ptr(root, nchildren - 1, @@ -1675,12 +1678,12 @@ static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key) if (ret < 0) return ret; node = (struct nilfs_btree_node *)bh->b_data; + nchildren = nilfs_btree_node_get_nchildren(node); break; default: return 0; } - nchildren = nilfs_btree_node_get_nchildren(node); maxkey = nilfs_btree_node_get_key(node, nchildren - 1); nextmaxkey = (nchildren > 1) ? nilfs_btree_node_get_key(node, nchildren - 2) : 0; -- Gitee