UBUNTU-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
02 / AFFECTED SOFTWARE
Affected packages
29 explicit affected versions
10 explicit affected versions
1 explicit affected versions
11 explicit affected versions
9 explicit affected versions
2 explicit affected versions
7 explicit affected versions
26 explicit affected versions
37 explicit affected versions
1 explicit affected versions
9 explicit affected versions
10 explicit affected versions
10 explicit affected versions
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13 explicit affected versions
10 explicit affected versions
37 explicit affected versions
7 explicit affected versions
8 explicit affected versions
4 explicit affected versions
8 explicit affected versions
23 explicit affected versions
7 explicit affected versions
10 explicit affected versions
10 explicit affected versions
33 explicit affected versions
16 explicit affected versions
6 explicit affected versions
2 explicit affected versions
12 explicit affected versions
38 explicit affected versions
51 explicit affected versions
13 explicit affected versions
10 explicit affected versions
10 explicit affected versions
13 explicit affected versions
1 explicit affected versions
10 explicit affected versions
3 explicit affected versions
8 explicit affected versions
2 explicit affected versions
8 explicit affected versions
2 explicit affected versions
21 explicit affected versions
6 explicit affected versions
13 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
26 explicit affected versions
7 explicit affected versions
7 explicit affected versions
23 explicit affected versions
3 explicit affected versions
5 explicit affected versions
3 explicit affected versions
3 explicit affected versions
26 explicit affected versions
12 explicit affected versions
44 explicit affected versions
1 explicit affected versions
4 explicit affected versions
4 explicit affected versions
16 explicit affected versions
9 explicit affected versions
12 explicit affected versions
13 explicit affected versions
7 explicit affected versions
9 explicit affected versions
5 explicit affected versions
7 explicit affected versions
10 explicit affected versions
14 explicit affected versions
18 explicit affected versions
3 explicit affected versions
16 explicit affected versions
43 explicit affected versions
4 explicit affected versions
11 explicit affected versions
35 explicit affected versions
12 explicit affected versions
6 explicit affected versions
12 explicit affected versions
50 explicit affected versions
12 explicit affected versions
27 explicit affected versions
12 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/682886ec69d22363819a83ddddd5d66cb5c791e1
- https://git.kernel.org/stable/c/682886ec69d22363819a83ddddd5d66cb5c791e1
- https://git.kernel.org/stable/c/b0fdabc908a7f81d12382c87ca9e46a9c2e14042
- https://ubuntu.com/security/CVE-2024-35846
- https://ubuntu.com/security/notices/USN-6949-1
- https://ubuntu.com/security/notices/USN-6949-2
- https://ubuntu.com/security/notices/USN-6952-1
- https://ubuntu.com/security/notices/USN-6952-2
- https://ubuntu.com/security/notices/USN-6955-1
- https://www.cve.org/CVERecord?id=CVE-2024-35846