ghsa-m8cg-xc2p-r3fc
Vulnerability from github
Published
2023-03-30 20:17
Modified
2023-03-30 20:17
Severity ?
2.5 (Low) - CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:L
Summary
rootless: `/sys/fs/cgroup` is writable when cgroupns isn't unshared in runc
Details

Impact

It was found that rootless runc makes /sys/fs/cgroup writable in following conditons: 1. when runc is executed inside the user namespace, and the config.json does not specify the cgroup namespace to be unshared (e.g.., (docker|podman|nerdctl) run --cgroupns=host, with Rootless Docker/Podman/nerdctl) 2. or, when runc is executed outside the user namespace, and /sys is mounted with rbind, ro (e.g., runc spec --rootless; this condition is very rare)

A container may gain the write access to user-owned cgroup hierarchy /sys/fs/cgroup/user.slice/... on the host . Other users's cgroup hierarchies are not affected.

Patches

v1.1.5 (planned)

Workarounds

  • Condition 1: Unshare the cgroup namespace ((docker|podman|nerdctl) run --cgroupns=private). This is the default behavior of Docker/Podman/nerdctl on cgroup v2 hosts.
  • Condition 2 (very rare): add /sys/fs/cgroup to maskedPaths
Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/opencontainers/runc"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-25809"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-281"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-03-30T20:17:24Z",
    "nvd_published_at": "2023-03-29T19:15:00Z",
    "severity": "LOW"
  },
  "details": "### Impact\nIt was found that rootless runc makes `/sys/fs/cgroup` writable in following conditons:\n1. when runc is executed inside the user namespace, and the `config.json` does not specify the cgroup namespace to be unshared (e.g.., `(docker|podman|nerdctl) run --cgroupns=host`, with Rootless Docker/Podman/nerdctl)\n2. or, when runc is executed outside the user namespace, and `/sys` is mounted with `rbind, ro` (e.g., `runc spec --rootless`; this condition is very rare)\n\nA container may gain the write access to user-owned cgroup hierarchy `/sys/fs/cgroup/user.slice/...` on the host .\nOther users\u0027s cgroup hierarchies are not affected.\n\n### Patches\nv1.1.5 (planned)\n\n### Workarounds\n- Condition 1: Unshare the cgroup namespace (`(docker|podman|nerdctl) run --cgroupns=private)`. This is the default behavior of Docker/Podman/nerdctl on cgroup v2 hosts.\n- Condition 2 (very rare): add `/sys/fs/cgroup` to `maskedPaths`\n",
  "id": "GHSA-m8cg-xc2p-r3fc",
  "modified": "2023-03-30T20:17:24Z",
  "published": "2023-03-30T20:17:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/opencontainers/runc/security/advisories/GHSA-m8cg-xc2p-r3fc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-25809"
    },
    {
      "type": "WEB",
      "url": "https://github.com/opencontainers/runc/commit/0d62b950e60f6980b54fe3bafd9a9c608dc1df17"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/opencontainers/runc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "rootless: `/sys/fs/cgroup` is writable when cgroupns isn\u0027t unshared in runc"
}


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