GHSA-P594-VH26-GH4W

Vulnerability from github – Published: 2024-09-13 06:30 – Updated: 2025-11-04 00:31
VLAI?
Details

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

selinux,smack: don't bypass permissions check in inode_setsecctx hook

Marek Gresko reports that the root user on an NFS client is able to change the security labels on files on an NFS filesystem that is exported with root squashing enabled.

The end of the kerneldoc comment for __vfs_setxattr_noperm() states:

  • This function requires the caller to lock the inode's i_mutex before it
  • is executed. It also assumes that the caller will make the appropriate
  • permission checks.

nfsd_setattr() does do permissions checking via fh_verify() and nfsd_permission(), but those don't do all the same permissions checks that are done by security_inode_setxattr() and its related LSM hooks do.

Since nfsd_setattr() is the only consumer of security_inode_setsecctx(), simplest solution appears to be to replace the call to __vfs_setxattr_noperm() with a call to __vfs_setxattr_locked(). This fixes the above issue and has the added benefit of causing nfsd to recall conflicting delegations on a file when a client tries to change its security label.

Severity ?
4.4 (Medium)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2024-46695"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-276"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-13T06:15:14Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nselinux,smack: don\u0027t bypass permissions check in inode_setsecctx hook\n\nMarek Gresko reports that the root user on an NFS client is able to\nchange the security labels on files on an NFS filesystem that is\nexported with root squashing enabled.\n\nThe end of the kerneldoc comment for __vfs_setxattr_noperm() states:\n\n *  This function requires the caller to lock the inode\u0027s i_mutex before it\n *  is executed. It also assumes that the caller will make the appropriate\n *  permission checks.\n\nnfsd_setattr() does do permissions checking via fh_verify() and\nnfsd_permission(), but those don\u0027t do all the same permissions checks\nthat are done by security_inode_setxattr() and its related LSM hooks do.\n\nSince nfsd_setattr() is the only consumer of security_inode_setsecctx(),\nsimplest solution appears to be to replace the call to\n__vfs_setxattr_noperm() with a call to __vfs_setxattr_locked().  This\nfixes the above issue and has the added benefit of causing nfsd to\nrecall conflicting delegations on a file when a client tries to change\nits security label.",
  "id": "GHSA-p594-vh26-gh4w",
  "modified": "2025-11-04T00:31:24Z",
  "published": "2024-09-13T06:30:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-46695"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2dbc4b7bac60b02cc6e70d05bf6a7dfd551f9dda"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/459584258d47ec3cc6245a82e8a49c9d08eb8b57"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/76a0e79bc84f466999fa501fce5bf7a07641b8a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eebec98791d0137e455cc006411bb92a54250924"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f71ec019257ba4f7ab198bd948c5902a207bad96"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fe0cd53791119f6287b6532af8ce41576d664930"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}


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