Use After Free Affecting kernel-rt-debug-kvm package, versions <0:5.14.0-362.8.1.el9_3


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (5th percentile)

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  • Snyk IDSNYK-RHEL9-KERNELRTDEBUGKVM-8549027
  • published24 Dec 2024
  • disclosed21 Oct 2024

Introduced: 21 Oct 2024

CVE-2022-48988  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade RHEL:9 kernel-rt-debug-kvm to version 0:5.14.0-362.8.1.el9_3 or higher.
This issue was patched in RHSA-2023:6583.

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:9 relevant fixed versions and status.

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

memcg: fix possible use-after-free in memcg_write_event_control()

memcg_write_event_control() accesses the dentry->d_name of the specified control fd to route the write call. As a cgroup interface file can't be renamed, it's safe to access d_name as long as the specified file is a regular cgroup file. Also, as these cgroup interface files can't be removed before the directory, it's safe to access the parent too.

Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a call to __file_cft() which verified that the specified file is a regular cgroupfs file before further accesses. The cftype pointer returned from __file_cft() was no longer necessary and the commit inadvertently dropped the file type check with it allowing any file to slip through. With the invarients broken, the d_name and parent accesses can now race against renames and removals of arbitrary files and cause use-after-free's.

Fix the bug by resurrecting the file type check in __file_cft(). Now that cgroupfs is implemented through kernfs, checking the file operations needs to go through a layer of indirection. Instead, let's check the superblock and dentry type.

CVSS Scores

version 3.1