GHSA-HM4V-3PG5-6F5C
Vulnerability from github – Published: 2024-12-27 15:31 – Updated: 2025-11-03 21:31In 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.
{
"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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