一、漏洞信息
漏洞编号:CVE-2022-49850
漏洞归属组件:kernel
漏洞归属的版本:4.19.140,4.19.194,4.19.90,5.10.0,6.1.19,6.4.0,6.6.0
CVSS V3.0分值:
BaseScore:5.5 Medium
Vector:CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
漏洞简述:
In the Linux kernel, the following vulnerability has been resolved:nilfs2: fix deadlock in nilfs_count_free_blocks()A semaphore deadlock can occur if nilfs_get_block() detects metadatacorruption while locating data blocks and a superblock writeback occurs atthe same time:task 1 task 2------ ------* A file operation *nilfs_truncate() nilfs_get_block() down_read(rwsem A) <-- nilfs_bmap_lookup_contig() ... generic_shutdown_super() nilfs_put_super() * Prepare to write superblock * down_write(rwsem B) <-- nilfs_cleanup_super() * Detect b-tree corruption * nilfs_set_log_cursor() nilfs_bmap_convert_error() nilfs_count_free_blocks() __nilfs_error() down_read(rwsem A) <-- nilfs_set_error() down_write(rwsem B) <-- *** DEADLOCK ***Here, nilfs_get_block() readlocks rwsem A (= NILFS_MDT(dat_inode)->mi_sem)and then calls nilfs_bmap_lookup_contig(), but if it fails due to metadatacorruption, __nilfs_error() is called from nilfs_bmap_convert_error()inside the lock section.Since __nilfs_error() calls nilfs_set_error() unless the filesystem isread-only and nilfs_set_error() attempts to writelock rwsem B (=nilfs->ns_sem) to write back superblock exclusively, hierarchical lockacquisition occurs in the order rwsem A -> rwsem B.Now, if another task starts updating the superblock, it may writelockrwsem B during the lock sequence above, and can deadlock trying toreadlock rwsem A in nilfs_count_free_blocks().However, there is actually no need to take rwsem A innilfs_count_free_blocks() because it, within the lock section, only readsa single integer data on a shared struct withnilfs_sufile_get_ncleansegs(). This has been the case after commitaa474a220180 ( nilfs2: add local variable to cache the number of cleansegments ), that is, even before this bug was introduced.So, this resolves the deadlock problem by just not taking the semaphore innilfs_count_free_blocks().
漏洞公开时间:2025-05-01 23:16:08
漏洞创建时间:2025-05-02 01:24:00
漏洞详情参考链接:
https://nvd.nist.gov/vuln/detail/CVE-2022-49850
漏洞分析指导链接:
https://gitee.com/openeuler/cve-manager/blob/master/cve-vulner-manager/doc/md/manual.md
漏洞数据来源:
openBrain开源漏洞感知系统
漏洞补丁信息:
二、漏洞分析结构反馈
影响性分析说明:
In the Linux kernel, the following vulnerability has been resolved:nilfs2: fix deadlock in nilfs_count_free_blocks()A semaphore deadlock can occur if nilfs_get_block() detects metadatacorruption while locating data blocks and a superblock writeback occurs atthe same time:task 1 task 2------ ------* A file operation *nilfs_truncate() nilfs_get_block() down_read(rwsem A) <-- nilfs_bmap_lookup_contig() ... generic_shutdown_super() nilfs_put_super() * Prepare to write superblock * down_write(rwsem B) <-- nilfs_cleanup_super() * Detect b-tree corruption * nilfs_set_log_cursor() nilfs_bmap_convert_error() nilfs_count_free_blocks() __nilfs_error() down_read(rwsem A) <-- nilfs_set_error() down_write(rwsem B) <-- *** DEADLOCK ***Here, nilfs_get_block() readlocks rwsem A (= NILFS_MDT(dat_inode)->mi_sem)and then calls nilfs_bmap_lookup_contig(), but if it fails due to metadatacorruption, __nilfs_error() is called from nilfs_bmap_convert_error()inside the lock section.Since __nilfs_error() calls nilfs_set_error() unless the filesystem isread-only and nilfs_set_error() attempts to writelock rwsem B (=nilfs->ns_sem) to write back superblock exclusively, hierarchical lockacquisition occurs in the order rwsem A -> rwsem B.Now, if another task starts updating the superblock, it may writelockrwsem B during the lock sequence above, and can deadlock trying toreadlock rwsem A in nilfs_count_free_blocks().However, there is actually no need to take rwsem A innilfs_count_free_blocks() because it, within the lock section, only readsa single integer data on a shared struct withnilfs_sufile_get_ncleansegs(). This has been the case after commitaa474a220180 ("nilfs2: add local variable to cache the number of cleansegments"), that is, even before this bug was introduced.So, this resolves the deadlock problem by just not taking the semaphore innilfs_count_free_blocks().The Linux kernel CVE team has assigned CVE-2022-49850 to this issue.
openEuler评分:
5.5
Vector:CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
受影响版本排查(受影响/不受影响):
1.openEuler-20.03-LTS-SP4(4.19.90):受影响
2.master(6.6.0):不受影响
3.openEuler-22.03-LTS-SP3(5.10.0):不受影响
4.openEuler-22.03-LTS-SP4(5.10.0):不受影响
5.openEuler-24.03-LTS(6.6.0):不受影响
6.openEuler-24.03-LTS-Next(6.6.0):不受影响
7.openEuler-24.03-LTS-SP1(6.6.0):不受影响
8.openEuler-24.03-LTS-SP2(6.6.0):不受影响
修复是否涉及abi变化(是/否):
1.master(6.6.0):否
2.openEuler-20.03-LTS-SP4(4.19.90):否
3.openEuler-22.03-LTS-SP3(5.10.0):否
4.openEuler-22.03-LTS-SP4(5.10.0):否
5.openEuler-24.03-LTS(6.6.0):否
6.openEuler-24.03-LTS-Next(6.6.0):否
7.openEuler-24.03-LTS-SP1(6.6.0):否
8.openEuler-24.03-LTS-SP2(6.6.0):否
原因说明:
1.openEuler-20.03-LTS-SP4(4.19.90):正常修复
2.master(6.6.0):不受影响-漏洞代码不能被攻击者触发
3.openEuler-22.03-LTS-SP3(5.10.0):不受影响-漏洞代码不能被攻击者触发
4.openEuler-22.03-LTS-SP4(5.10.0):不受影响-漏洞代码不能被攻击者触发
5.openEuler-24.03-LTS(6.6.0):不受影响-漏洞代码不能被攻击者触发
6.openEuler-24.03-LTS-Next(6.6.0):不受影响-漏洞代码不能被攻击者触发
7.openEuler-24.03-LTS-SP1(6.6.0):不受影响-漏洞代码不能被攻击者触发
8.openEuler-24.03-LTS-SP2(6.6.0):不受影响-漏洞代码不能被攻击者触发
三、漏洞修复
安全公告链接:https://www.openeuler.org/zh/security/safety-bulletin/detail/?id=openEuler-SA-2025-1513
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说明:补丁链接仅供初步排查参考,实际可用性请人工再次确认,补丁下载验证可使用CVE补丁工具。
若补丁不准确,烦请在此issue下评论 '/report-patch 参考网址 补丁链接1,补丁链接2' 反馈正确信息,便于我们不断优化工具,不胜感激。
如 /report-patch https://security-tracker.debian.org/tracker/CVE-2021-3997 https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1
CVE-2022-49850
影响性分析说明:
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix deadlock in nilfs_count_free_blocks()
A semaphore deadlock can occur if nilfs_get_block() detects metadata
corruption while locating data blocks and a superblock writeback occurs at
the same time:
task 1 task 2
A file operation *
nilfs_truncate()
nilfs_get_block()
down_read(rwsem A) <--
nilfs_bmap_lookup_contig()
... generic_shutdown_super()
nilfs_put_super()
* Prepare to write superblock *
down_write(rwsem B) <--
nilfs_cleanup_super()
* Detect b-tree corruption * nilfs_set_log_cursor()
nilfs_bmap_convert_error() nilfs_count_free_blocks()
__nilfs_error() down_read(rwsem A) <--
nilfs_set_error()
down_write(rwsem B) <--
*** DEADLOCK ***
Here, nilfs_get_block() readlocks rwsem A (= NILFS_MDT(dat_inode)->mi_sem)
and then calls nilfs_bmap_lookup_contig(), but if it fails due to metadata
corruption, __nilfs_error() is called from nilfs_bmap_convert_error()
inside the lock section.
Since __nilfs_error() calls nilfs_set_error() unless the filesystem is
read-only and nilfs_set_error() attempts to writelock rwsem B (=
nilfs->ns_sem) to write back superblock exclusively, hierarchical lock
acquisition occurs in the order rwsem A -> rwsem B.
Now, if another task starts updating the superblock, it may writelock
rwsem B during the lock sequence above, and can deadlock trying to
readlock rwsem A in nilfs_count_free_blocks().
However, there is actually no need to take rwsem A in
nilfs_count_free_blocks() because it, within the lock section, only reads
a single integer data on a shared struct with
nilfs_sufile_get_ncleansegs(). This has been the case after commit
aa474a220180 ("nilfs2: add local variable to cache the number of clean
segments"), that is, even before this bug was introduced.
So, this resolves the deadlock problem by just not taking the semaphore in
nilfs_count_free_blocks().
The Linux kernel CVE team has assigned CVE-2022-49850 to this issue.
openEuler评分:(评分和向量)
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
受影响版本排查(受影响/不受影响):
1.master(6.1.0):不受影响
2.openEuler-20.03-LTS-SP4:受影响
3.openEuler-22.03-LTS-SP3:不受影响
4.openEuler-22.03-LTS-SP4:不受影响
5.openEuler-24.03-LTS:不受影响
6.openEuler-24.03-LTS-Next:不受影响
7.openEuler-24.03-LTS-SP1:不受影响
8.openEuler-24.03-LTS-SP2:不受影响
修复是否涉及abi变化(是/否):
1.master(6.1.0):否
2.openEuler-20.03-LTS-SP4:否
3.openEuler-22.03-LTS-SP3:否
4.openEuler-22.03-LTS-SP4:否
5.openEuler-24.03-LTS:否
6.openEuler-24.03-LTS-Next:否
7.openEuler-24.03-LTS-SP1:否
8.openEuler-24.03-LTS-SP2:否
原因说明:
1.master(23.08.5):不受影响-漏洞代码不能被攻击者触发
2.openEuler-20.03-LTS-SP4:正常修复
3.openEuler-22.03-LTS-SP3:不受影响-漏洞代码不能被攻击者触发
4.openEuler-22.03-LTS-SP4:不受影响-漏洞代码不能被攻击者触发
5.openEuler-24.03-LTS:不受影响-漏洞代码不能被攻击者触发
6.openEuler-24.03-LTS-Next:不受影响-漏洞代码不能被攻击者触发
7.openEuler-24.03-LTS-SP1:不受影响-漏洞代码不能被攻击者触发
8.openEuler-24.03-LTS-SP2:不受影响-漏洞代码不能被攻击者触发
CVE-2022-49850
影响性分析说明:
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix deadlock in nilfs_count_free_blocks()
A semaphore deadlock can occur if nilfs_get_block() detects metadata
corruption while locating data blocks and a superblock writeback occurs at
the same time:
task 1 task 2
A file operation *
nilfs_truncate()
nilfs_get_block()
down_read(rwsem A) <--
nilfs_bmap_lookup_contig()
... generic_shutdown_super()
nilfs_put_super()
* Prepare to write superblock *
down_write(rwsem B) <--
nilfs_cleanup_super()
* Detect b-tree corruption * nilfs_set_log_cursor()
nilfs_bmap_convert_error() nilfs_count_free_blocks()
__nilfs_error() down_read(rwsem A) <--
nilfs_set_error()
down_write(rwsem B) <--
*** DEADLOCK ***
Here, nilfs_get_block() readlocks rwsem A (= NILFS_MDT(dat_inode)->mi_sem)
and then calls nilfs_bmap_lookup_contig(), but if it fails due to metadata
corruption, __nilfs_error() is called from nilfs_bmap_convert_error()
inside the lock section.
Since __nilfs_error() calls nilfs_set_error() unless the filesystem is
read-only and nilfs_set_error() attempts to writelock rwsem B (=
nilfs->ns_sem) to write back superblock exclusively, hierarchical lock
acquisition occurs in the order rwsem A -> rwsem B.
Now, if another task starts updating the superblock, it may writelock
rwsem B during the lock sequence above, and can deadlock trying to
readlock rwsem A in nilfs_count_free_blocks().
However, there is actually no need to take rwsem A in
nilfs_count_free_blocks() because it, within the lock section, only reads
a single integer data on a shared struct with
nilfs_sufile_get_ncleansegs(). This has been the case after commit
aa474a220180 ("nilfs2: add local variable to cache the number of clean
segments"), that is, even before this bug was introduced.
So, this resolves the deadlock problem by just not taking the semaphore in
nilfs_count_free_blocks().
The Linux kernel CVE team has assigned CVE-2022-49850 to this issue.
openEuler评分:(评分和向量)
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
受影响版本排查(受影响/不受影响):
1.master(6.1.0):不受影响
2.openEuler-20.03-LTS-SP4:受影响
3.openEuler-22.03-LTS-SP3:不受影响
4.openEuler-22.03-LTS-SP4:不受影响
5.openEuler-24.03-LTS:不受影响
6.openEuler-24.03-LTS-Next:不受影响
7.openEuler-24.03-LTS-SP1:不受影响
8.openEuler-24.03-LTS-SP2:不受影响
修复是否涉及abi变化(是/否):
1.master(6.1.0):否
2.openEuler-20.03-LTS-SP4:否
3.openEuler-22.03-LTS-SP3:否
4.openEuler-22.03-LTS-SP4:否
5.openEuler-24.03-LTS:否
6.openEuler-24.03-LTS-Next:否
7.openEuler-24.03-LTS-SP1:否
8.openEuler-24.03-LTS-SP2:否
原因说明:
1.master(23.08.5):不受影响-漏洞代码不能被攻击者触发
2.openEuler-20.03-LTS-SP4:正常修复
3.openEuler-22.03-LTS-SP3:不受影响-漏洞代码不能被攻击者触发
4.openEuler-22.03-LTS-SP4:不受影响-漏洞代码不能被攻击者触发
5.openEuler-24.03-LTS:不受影响-漏洞代码不能被攻击者触发
6.openEuler-24.03-LTS-Next:不受影响-漏洞代码不能被攻击者触发
7.openEuler-24.03-LTS-SP1:不受影响-漏洞代码不能被攻击者触发
8.openEuler-24.03-LTS-SP2:不受影响-漏洞代码不能被攻击者触发
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