Bug 1225149 (CVE-2021-47342) - VUL-0: CVE-2021-47342: kernel: ext4: fix possible UAF when remounting r/o a mmp-protected file system
Summary: VUL-0: CVE-2021-47342: kernel: ext4: fix possible UAF when remounting r/o a m...
Status: RESOLVED UPSTREAM
Alias: CVE-2021-47342
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P2 - High : Major
Target Milestone: ---
Assignee: Security Team bot
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/406943/
Whiteboard: CVSSv3.1:SUSE:CVE-2021-47342:7.0:(AV:...
Keywords:
Depends on:
Blocks: 1225154
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Reported: 2024-05-23 14:08 UTC by SMASH SMASH
Modified: 2024-06-14 11:31 UTC (History)
6 users (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---


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Description SMASH SMASH 2024-05-23 14:08:18 UTC
In the Linux kernel, the following vulnerability has been resolved:

ext4: fix possible UAF when remounting r/o a mmp-protected file system

After commit 618f003199c6 ("ext4: fix memory leak in
ext4_fill_super"), after the file system is remounted read-only, there
is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to
point at freed memory, which the call to ext4_stop_mmpd() can trip
over.

Fix this by only allowing kmmpd() to exit when it is stopped via
ext4_stop_mmpd().

Bug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47342
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2021/CVE-2021-47342.mbox
https://git.kernel.org/stable/c/b663890d854403e566169f7e90aed5cd6ff64f6b
https://git.kernel.org/stable/c/7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd
https://git.kernel.org/stable/c/61bb4a1c417e5b95d9edb4f887f131de32e419cb
https://www.cve.org/CVERecord?id=CVE-2021-47342
https://bugzilla.redhat.com/show_bug.cgi?id=2282417
Comment 6 Jan Kara 2024-06-14 11:10:37 UTC
I've added the blacklist entry to SLE12-SP5. Nothing to be backported here so reassigning back to security team.
Comment 7 Marcus Meissner 2024-06-14 11:31:20 UTC
fixed