Use After Free Affecting gfs2-kmp-default package, versions <5.3.18-150300.59.164.1


Severity

Recommended
medium

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (5th percentile)

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  • Snyk IDSNYK-SLES153-GFS2KMPDEFAULT-7363543
  • published25 Jun 2024
  • disclosed24 Jun 2024

Introduced: 24 Jun 2024

CVE-2021-47254  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade SLES:15.3 gfs2-kmp-default to version 5.3.18-150300.59.164.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream gfs2-kmp-default package and not the gfs2-kmp-default package as distributed by SLES. See How to fix? for SLES:15.3 relevant fixed versions and status.

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

gfs2: Fix use-after-free in gfs2_glock_shrink_scan

The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put().

On the shrink scan path, the same flag is cleared under lru_lock but because of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the put side can be made without deleting the glock from the lru list.

Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to ensure correct behavior on both sides - clear GLF_LRU after list_del under lru_lock.

CVSS Scores

version 3.1