GHSA-HM4V-3PG5-6F5C

Vulnerability from github – Published: 2024-12-27 15:31 – Updated: 2025-11-03 21:31
VLAI
Details

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

cachefiles: Fix NULL pointer dereference in object->file

At present, the object->file has the NULL pointer dereference problem in ondemand-mode. The root cause is that the allocated fd and object->file lifetime are inconsistent, and the user-space invocation to anon_fd uses object->file. Following is the process that triggers the issue:

  [write fd]                [umount]

cachefiles_ondemand_fd_write_iter fscache_cookie_state_machine cachefiles_withdraw_cookie if (!file) return -ENOBUFS cachefiles_clean_up_object cachefiles_unmark_inode_in_use fput(object->file) object->file = NULL // file NULL pointer dereference! __cachefiles_write(..., file, ...)

Fix this issue by add an additional reference count to the object->file before write/llseek, and decrement after it finished.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2024-56549"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-12-27T14:15:34Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncachefiles: Fix NULL pointer dereference in object-\u003efile\n\nAt present, the object-\u003efile has the NULL pointer dereference problem in\nondemand-mode. The root cause is that the allocated fd and object-\u003efile\nlifetime are inconsistent, and the user-space invocation to anon_fd uses\nobject-\u003efile. Following is the process that triggers the issue:\n\n\t  [write fd]\t\t\t\t[umount]\ncachefiles_ondemand_fd_write_iter\n\t\t\t\t       fscache_cookie_state_machine\n\t\t\t\t\t cachefiles_withdraw_cookie\n  if (!file) return -ENOBUFS\n\t\t\t\t\t   cachefiles_clean_up_object\n\t\t\t\t\t     cachefiles_unmark_inode_in_use\n\t\t\t\t\t     fput(object-\u003efile)\n\t\t\t\t\t     object-\u003efile = NULL\n  // file NULL pointer dereference!\n  __cachefiles_write(..., file, ...)\n\nFix this issue by add an additional reference count to the object-\u003efile\nbefore write/llseek, and decrement after it finished.",
  "id": "GHSA-hm4v-3pg5-6f5c",
  "modified": "2025-11-03T21:31:50Z",
  "published": "2024-12-27T15:31:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56549"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/31ad74b20227ce6b40910ff78b1c604e42975cf1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/785408bbafcfa24c9fc5b251f03fd0780ce182bd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9582c7664103c9043e80a78f5c382aa6bdd67418"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d6bba3ece960129a553d4b16f1b00c884dc0993a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f98770440c9bc468e2fd878212ec9526dbe08293"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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