Use After Free Affecting kernel-rt-debug-kvm package, versions <0:4.18.0-553.22.1.rt7.363.el8_10


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELRTDEBUGKVM-7557371
  • published24 Jul 2024
  • disclosed23 Jul 2024

Introduced: 23 Jul 2024

CVE-2024-41012  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade RHEL:8 kernel-rt-debug-kvm to version 0:4.18.0-553.22.1.rt7.363.el8_10 or higher.
This issue was patched in RHSA-2024:7001.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-kvm package and not the kernel-rt-debug-kvm package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

filelock: Remove locks reliably when fcntl/close race is detected

When fcntl_setlk() races with close(), it removes the created lock with do_lock_file_wait(). However, LSMs can allow the first do_lock_file_wait() that created the lock while denying the second do_lock_file_wait() that tries to remove the lock. Separately, posix_lock_file() could also fail to remove a lock due to GFP_KERNEL allocation failure (when splitting a range in the middle).

After the bug has been triggered, use-after-free reads will occur in lock_get_status() when userspace reads /proc/locks. This can likely be used to read arbitrary kernel memory, but can't corrupt kernel memory.

Fix it by calling locks_remove_posix() instead, which is designed to reliably get rid of POSIX locks associated with the given file and files_struct and is also used by filp_flush().

CVSS Scores

version 3.1