PT-2024-36853 · Linux+7 · Linux Kernel+7
Zizhi Wo
·
Published
2024-11-11
·
Updated
2026-01-13
·
CVE-2024-56549
CVSS v3.1
5.5
Medium
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel (affected versions not specified)
Description
The issue is related to a NULL pointer dereference problem in the
object->file within the Linux kernel's cachefiles module, specifically in ondemand-mode. The root cause is the inconsistency between the allocated file descriptor and the lifetime of object->file, which is used by the user-space invocation to anon fd. The process that triggers the issue involves a series of function calls, including cachefiles ondemand fd write iter, fscache cookie state machine, cachefiles withdraw cookie, and cachefiles write, leading to a NULL pointer dereference when object->file is accessed after being set to NULL.Recommendations
To resolve this issue, add an additional reference count to the
object->file before write or llseek operations, and decrement the reference count after these operations are completed. This ensures that object->file remains valid and accessible throughout the process, preventing the NULL pointer dereference.Note: Since the affected versions are not explicitly specified, it is crucial to apply this fix to all versions of the Linux kernel that are potentially vulnerable to this issue.
Exploit
Fix
NULL Pointer Dereference
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Weakness Enumeration
Related Identifiers
Affected Products
Alt Linux
Astra Linux
Debian
Linuxmint
Linux Kernel
Red Os
Suse
Ubuntu