CVE-2021-46937: linux kernel Resource Exposure — Fix

Description

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Weakness Type (CWE)

CWE-668 CWE-668

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.15.0 — 5.15.13

References

Advisories & Patches

https://git.kernel.org/stable/c/ebb3f994dd92f8fb4d70c7541091216c1e10cb71 https://git.kernel.org/stable/c/ffe4a1ba1a82c416a6b3a09d46594f6a885ae141 https://git.kernel.org/stable/c/ebb3f994dd92f8fb4d70c7541091216c1e10cb71 https://git.kernel.org/stable/c/ffe4a1ba1a82c416a6b3a09d46594f6a885ae141

Frequently Asked Questions

What is CVE-2021-46937? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-46937? +

CVE-2021-46937 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-46937? +

CVE-2021-46937 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-46937? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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