Resource Leak Affecting kernel-kdump package, versions *


Severity

Recommended
low

Based on CentOS security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-CENTOS6-KERNELKDUMP-6452030
  • published17 Mar 2024
  • disclosed15 Mar 2024

Introduced: 15 Mar 2024

CVE-2021-47119  (opens in a new tab)
CWE-402  (opens in a new tab)

How to fix?

There is no fixed version for Centos:6 kernel-kdump.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-kdump package and not the kernel-kdump package as distributed by Centos. See How to fix? for Centos:6 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