ghsa-hm4v-3pg5-6f5c
Vulnerability from github
Published
2024-12-27 15:31
Modified
2025-02-21 15:31
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.

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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->file\n\nAt present, the object->file has the NULL pointer dereference problem in\nondemand-mode. The root cause is that the allocated fd and object->file\nlifetime are inconsistent, and the user-space invocation to anon_fd uses\nobject->file. 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->file)\n\t\t\t\t\t     object->file = NULL\n  // file NULL pointer dereference!\n  __cachefiles_write(..., file, ...)\n\nFix this issue by add an additional reference count to the object->file\nbefore write/llseek, and decrement after it finished.",
   id: "GHSA-hm4v-3pg5-6f5c",
   modified: "2025-02-21T15:31:58Z",
   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",
      },
   ],
   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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