CVE-2021-46937 mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'

2024-02-2709:44:03

Linux

github.com

linux kernel

cve-2021-46937

damon

debugfs

struct pid

memory leak

AI Score

6.8

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4bc05954d007",
        "lessThan": "ffe4a1ba1a82",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4bc05954d007",
        "lessThan": "ebb3f994dd92",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "mm/damon/dbgfs.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.15"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.15",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "5.15.13",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "5.16",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "mm/damon/dbgfs.c"
    ],
    "defaultStatus": "affected"
  }
]