Improper Input Validation Affecting kernel-rt-trace package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Improper Input Validation vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-RHEL7-KERNELRTTRACE-6328606
  • published29 Feb 2024
  • disclosed28 Feb 2024

Introduced: 28 Feb 2024

CVE-2021-46990  (opens in a new tab)
CWE-20  (opens in a new tab)
First added by Snyk

How to fix?

There is no fixed version for RHEL:7 kernel-rt-trace.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-trace package and not the kernel-rt-trace package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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

powerpc/64s: Fix crashes when toggling entry flush barrier

The entry flush mitigation can be enabled/disabled at runtime via a debugfs file (entry_flush), which causes the kernel to patch itself to enable/disable the relevant mitigations.

However depending on which mitigation we're using, it may not be safe to do that patching while other CPUs are active. For example the following crash:

sleeper[15639]: segfault (11) at c000000000004c20 nip c000000000004c20 lr c000000000004c20

Shows that we returned to userspace with a corrupted LR that points into the kernel, due to executing the partially patched call to the fallback entry flush (ie. we missed the LR restore).

Fix it by doing the patching under stop machine. The CPUs that aren't doing the patching will be spinning in the core of the stop machine logic. That is currently sufficient for our purposes, because none of the patching we do is to that code or anywhere in the vicinity.

CVSS Scores

version 3.1