ghsa-657p-cp5v-hvxv
Vulnerability from github
Published
2024-05-17 15:31
Modified
2024-12-30 18:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

Show details on source website

To clipboard 

{
   affected: [],
   aliases: [
      "CVE-2024-35846",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-476",
      ],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-05-17T15:15:21Z",
      severity: "MODERATE",
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: zswap: fix shrinker NULL crash with cgroup_disable=memory\n\nChristian reports a NULL deref in zswap that he bisected down to the zswap\nshrinker.  The issue also cropped up in the bug trackers of libguestfs [1]\nand the Red Hat bugzilla [2].\n\nThe problem is that when memcg is disabled with the boot time flag, the\nzswap shrinker might get called with sc->memcg == NULL.  This is okay in\nmany places, like the lruvec operations.  But it crashes in\nmemcg_page_state() - which is only used due to the non-node accounting of\ncgroup's the zswap memory to begin with.\n\nNhat spotted that the memcg can be NULL in the memcg-disabled case, and I\nwas then able to reproduce the crash locally as well.\n\n[1] https://github.com/libguestfs/libguestfs/issues/139\n[2] https://bugzilla.redhat.com/show_bug.cgi?id=2275252",
   id: "GHSA-657p-cp5v-hvxv",
   modified: "2024-12-30T18:30:40Z",
   published: "2024-05-17T15:31:12Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2024-35846",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/682886ec69d22363819a83ddddd5d66cb5c791e1",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/b0fdabc908a7f81d12382c87ca9e46a9c2e14042",
      },
   ],
   schema_version: "1.4.0",
   severity: [
      {
         score: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
         type: "CVSS_V3",
      },
   ],
}


Log in or create an account to share your comment.

Security Advisory comment format.

This schema specifies the format of a comment related to a security advisory.

UUIDv4 of the comment
UUIDv4 of the Vulnerability-Lookup instance
When the comment was created originally
When the comment was last updated
Title of the comment
Description of the comment
The identifier of the vulnerability (CVE ID, GHSA-ID, PYSEC ID, etc.).



Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.