Vulnerability Details CVE-2024-35846
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
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 3.1%
CVSS Severity
CVSS v3 Score 5.5
References
Products affected by CVE-2024-35846
-
cpe:2.3:o:linux:linux_kernel:6.8
-
cpe:2.3:o:linux:linux_kernel:6.8.1
-
cpe:2.3:o:linux:linux_kernel:6.8.2
-
cpe:2.3:o:linux:linux_kernel:6.8.3
-
cpe:2.3:o:linux:linux_kernel:6.8.4
-
cpe:2.3:o:linux:linux_kernel:6.8.5
-
cpe:2.3:o:linux:linux_kernel:6.8.6
-
cpe:2.3:o:linux:linux_kernel:6.8.7
-
cpe:2.3:o:linux:linux_kernel:6.8.8
-
cpe:2.3:o:linux:linux_kernel:6.9