CVE-2024-26993 fs: sysfs: Fix reference leak in sysfs_break_active_protection()

2024-05-0105:28:02

Linux

github.com

linux kernel

vulnerability

sysfs_break_active_protection

reference leak

kernfs_find_and_get

sysfs_unbreak_active_protection

kobject_put

AI Score

6.6

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

In the Linux kernel, the following vulnerability has been resolved:

fs: sysfs: Fix reference leak in sysfs_break_active_protection()

The sysfs_break_active_protection() routine has an obvious reference
leak in its error path. If the call to kernfs_find_and_get() fails then
kn will be NULL, so the companion sysfs_unbreak_active_protection()
routine won’t get called (and would only cause an access violation by
trying to dereference kn->parent if it was called). As a result, the
reference to kobj acquired at the start of the function will never be
released.

Fix the leak by adding an explicit kobject_put() call when kn is NULL.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "f28bba37fe24",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "57baab0f376b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "84bd4c2ae9c3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "43f00210cb25",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "5d43e072285e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "ac107356aabc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "a4c99b57d43b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2afc9166f79b",
        "lessThan": "a90bca2228c0",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/sysfs/file.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.19"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.19",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "4.19.313",
        "versionType": "custom",
        "lessThanOrEqual": "4.19.*"
      },
      {
        "status": "unaffected",
        "version": "5.4.275",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.216",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.157",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.88",
        "versionType": "custom",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.29",
        "versionType": "custom",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.8.8",
        "versionType": "custom",
        "lessThanOrEqual": "6.8.*"
      },
      {
        "status": "unaffected",
        "version": "6.9",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/sysfs/file.c"
    ],
    "defaultStatus": "affected"
  }
]