CVE-2024-35846

high

Description

In the Linux kernel, the following vulnerability has been resolved: mm: zswap: fix shrinker NULL crash with cgroup_disable=memory Christian reports a NULL deref in zswap that he bisected down to the zswap shrinker. The issue also cropped up in the bug trackers of libguestfs [1] and the Red Hat bugzilla [2]. The problem is that when memcg is disabled with the boot time flag, the zswap shrinker might get called with sc->memcg == NULL. This is okay in many places, like the lruvec operations. But it crashes in memcg_page_state() - which is only used due to the non-node accounting of cgroup's the zswap memory to begin with. Nhat spotted that the memcg can be NULL in the memcg-disabled case, and I was then able to reproduce the crash locally as well. [1] https://github.com/libguestfs/libguestfs/issues/139 [2] https://bugzilla.redhat.com/show_bug.cgi?id=2275252

References

https://git.kernel.org/stable/c/b0fdabc908a7f81d12382c87ca9e46a9c2e14042

https://git.kernel.org/stable/c/682886ec69d22363819a83ddddd5d66cb5c791e1

Details

Source: Mitre, NVD

Published: 2024-05-17

Updated: 2024-05-17

Risk Information

CVSS v2

Base Score: 6.9

Vector: CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C

Severity: Medium

CVSS v3

Base Score: 7.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity: High