CVE-2021-47119 Affecting kernel-default-devel package, versions <5.3.18-150200.24.188.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-SLES152-KERNELDEFAULTDEVEL-6691055
  • published29 Apr 2024
  • disclosed26 Apr 2024

Introduced: 26 Apr 2024

CVE-2021-47119  (opens in a new tab)

How to fix?

Upgrade SLES:15.2 kernel-default-devel to version 5.3.18-150200.24.188.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-devel package and not the kernel-default-devel package as distributed by SLES. See How to fix? for SLES:15.2 relevant fixed versions and status.

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

ext4: fix memory leak in ext4_fill_super

Buffer head references must be released before calling kill_bdev(); otherwise the buffer head (and its page referenced by b_data) will not be freed by kill_bdev, and subsequently that bh will be leaked.

If blocksizes differ, sb_set_blocksize() will kill current buffers and page cache by using kill_bdev(). And then super block will be reread again but using correct blocksize this time. sb_set_blocksize() didn't fully free superblock page and buffer head, and being busy, they were not freed and instead leaked.

This can easily be reproduced by calling an infinite loop of:

systemctl start <ext4_on_lvm>.mount, and systemctl stop <ext4_on_lvm>.mount

... since systemd creates a cgroup for each slice which it mounts, and the bh leak get amplified by a dying memory cgroup that also never gets freed, and memory consumption is much more easily noticed.

CVSS Scores

version 3.1