Bug 1220488 (CVE-2021-46937) - VUL-0: CVE-2021-46937: kernel: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'
Summary: VUL-0: CVE-2021-46937: kernel: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbg...
Status: RESOLVED FIXED
Alias: CVE-2021-46937
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P5 - None : Normal
Target Milestone: ---
Assignee: Kernel Bugs
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/395292/
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Reported: 2024-02-27 16:45 UTC by SMASH SMASH
Modified: 2024-02-27 16:45 UTC (History)
1 user (show)

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Found By: Security Response Team
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Description SMASH SMASH 2024-02-27 16:45:08 UTC 
In the Linux kernel, the following vulnerability has been resolved:

mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'

DAMON debugfs interface increases the reference counts of 'struct pid's
for targets from the 'target_ids' file write callback
('dbgfs_target_ids_write()'), but decreases the counts only in DAMON
monitoring termination callback ('dbgfs_before_terminate()').

Therefore, when 'target_ids' file is repeatedly written without DAMON
monitoring start/termination, the reference count is not decreased and
therefore memory for the 'struct pid' cannot be freed.  This commit
fixes this issue by decreasing the reference counts when 'target_ids' is
written.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-46937
https://www.cve.org/CVERecord?id=CVE-2021-46937
https://git.kernel.org/stable/c/ebb3f994dd92f8fb4d70c7541091216c1e10cb71
https://git.kernel.org/stable/c/ffe4a1ba1a82c416a6b3a09d46594f6a885ae141