CVE-2021-46937

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.

CVSS Metrics

• v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Trends

Current EPSS score: 0.22%• Percentile: 13%

Techniques & Countermeasures

• CWE-668•Exposure of Resource to Wrong Sphere

  The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.

Affected Systems

• debian•linux

  all | < 5.15.15-1 | < 5.15.15-1 | < 5.15.15-1

• linux•linux

  ≥ 4bc05954d0076655cfaf6f0135585bdc20cd6b11, < ffe4a1ba1a82c416a6b3a09d46594f6a885ae141 | ≥ 4bc05954d0076655cfaf6f0135585bdc20cd6b11, < ebb3f994dd92f8fb4d70c7541091216c1e10cb71 | 5.15

• linux•linux_kernel

  ≥ 5.15.0, < 5.15.13

References (3)

• https://git.kernel.org/stable/c/ffe4a1ba1a82c416a6b3a09d46594f6a885ae141
• https://git.kernel.org/stable/c/ebb3f994dd92f8fb4d70c7541091216c1e10cb71
• https://security-tracker.debian.org/tracker/CVE-2021-46937