GHSA-R35M-5R25-V2FX

Vulnerability from github – Published: 2026-02-14 18:30 – Updated: 2026-02-14 18:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

ceph: fix NULL pointer dereference in ceph_mds_auth_match()

The CephFS kernel client has regression starting from 6.18-rc1. We have issue in ceph_mds_auth_match() if fs_name == NULL:

const char fs_name = mdsc->fsc->mount_options->mds_namespace;
...
if (auth->match.fs_name && strcmp(auth->match.fs_name, fs_name)) {
        / fsname mismatch, try next one */
        return 0;
}

Patrick Donnelly suggested that: In summary, we should definitely start decoding fs_name from the MDSMap and do strict authorizations checks against it. Note that the -o mds_namespace=foo should only be used for selecting the file system to mount and nothing else. It's possible no mds_namespace is specified but the kernel will mount the only file system that exists which may have name "foo".

This patch reworks ceph_mdsmap_decode() and namespace_equals() with the goal of supporting the suggested concept. Now struct ceph_mdsmap contains m_fs_name field that receives copy of extracted FS name by ceph_extract_encoded_string(). For the case of "old" CephFS file systems, it is used "cephfs" name.

[ idryomov: replace redundant %*pE with %s in ceph_mdsmap_decode(), get rid of a series of strlen() calls in ceph_namespace_match(), drop changes to namespace_equals() body to avoid treating empty mds_namespace as equal, drop changes to ceph_mdsc_handle_fsmap() as namespace_equals() isn't an equivalent substitution there ]

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23189"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-02-14T17:15:56Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix NULL pointer dereference in ceph_mds_auth_match()\n\nThe CephFS kernel client has regression starting from 6.18-rc1.\nWe have issue in ceph_mds_auth_match() if fs_name == NULL:\n\n    const char fs_name = mdsc-\u003efsc-\u003emount_options-\u003emds_namespace;\n    ...\n    if (auth-\u003ematch.fs_name \u0026\u0026 strcmp(auth-\u003ematch.fs_name, fs_name)) {\n            / fsname mismatch, try next one */\n            return 0;\n    }\n\nPatrick Donnelly suggested that: In summary, we should definitely start\ndecoding `fs_name` from the MDSMap and do strict authorizations checks\nagainst it. Note that the `-o mds_namespace=foo` should only be used for\nselecting the file system to mount and nothing else. It\u0027s possible\nno mds_namespace is specified but the kernel will mount the only\nfile system that exists which may have name \"foo\".\n\nThis patch reworks ceph_mdsmap_decode() and namespace_equals() with\nthe goal of supporting the suggested concept. Now struct ceph_mdsmap\ncontains m_fs_name field that receives copy of extracted FS name\nby ceph_extract_encoded_string(). For the case of \"old\" CephFS file\nsystems, it is used \"cephfs\" name.\n\n[ idryomov: replace redundant %*pE with %s in ceph_mdsmap_decode(),\n  get rid of a series of strlen() calls in ceph_namespace_match(),\n  drop changes to namespace_equals() body to avoid treating empty\n  mds_namespace as equal, drop changes to ceph_mdsc_handle_fsmap()\n  as namespace_equals() isn\u0027t an equivalent substitution there ]",
  "id": "GHSA-r35m-5r25-v2fx",
  "modified": "2026-02-14T18:30:16Z",
  "published": "2026-02-14T18:30:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23189"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/57b36ffc8881dd455d875f85c105901974af2130"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7987cce375ac8ce98e170a77aa2399f2cf6eb99f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c6f8326f26bd20d648d9a55afd68148d1b6afe28"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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