CVE-2024-38570 gfs2: Fix potential glock use-after-free on unmount

2024-06-1913:35:36

Linux

www.cve.org

linux kernel

vulnerability

gfs2

dlm lockspace

lock contention

notifications

0.0004 Low

EPSS

Percentile

15.7%

JSON

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

gfs2: Fix potential glock use-after-free on unmount

When a DLM lockspace is released and there ares still locks in that
lockspace, DLM will unlock those locks automatically. Commit
fb6791d100d1b started exploiting this behavior to speed up filesystem
unmount: gfs2 would simply free glocks it didn’t want to unlock and then
release the lockspace. This didn’t take the bast callbacks for
asynchronous lock contention notifications into account, which remain
active until until a lock is unlocked or its lockspace is released.

To prevent those callbacks from accessing deallocated objects, put the
glocks that should not be unlocked on the sd_dead_glocks list, release
the lockspace, and only then free those glocks.

As an additional measure, ignore unexpected ast and bast callbacks if
the receiving glock is dead.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/gfs2/glock.c",
      "fs/gfs2/glock.h",
      "fs/gfs2/incore.h",
      "fs/gfs2/lock_dlm.c",
      "fs/gfs2/ops_fstype.c",
      "fs/gfs2/super.c"
    ],
    "versions": [
      {
        "version": "fb6791d100d1",
        "lessThan": "0636b34b4458",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fb6791d100d1",
        "lessThan": "e42e8a24d7f0",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fb6791d100d1",
        "lessThan": "501cd8fabf62",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fb6791d100d1",
        "lessThan": "d98779e68772",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/gfs2/glock.c",
      "fs/gfs2/glock.h",
      "fs/gfs2/incore.h",
      "fs/gfs2/lock_dlm.c",
      "fs/gfs2/ops_fstype.c",
      "fs/gfs2/super.c"
    ],
    "versions": [
      {
        "version": "3.8",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "3.8",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.33",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8.12",
        "lessThanOrEqual": "6.8.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9.3",
        "lessThanOrEqual": "6.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10-rc1",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]