GHSA-HGC7-RQX4-P393

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-05-27 15:33
VLAI
Details

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

smack: /smack/doi: accept previously used values

Writing to /smack/doi a value that has ever been written there in the past disables networking for non-ambient labels. E.g.

# cat /smack/doi
3
# netlabelctl -p cipso list
Configured CIPSO mappings (1)
 DOI value : 3
   mapping type : PASS_THROUGH
# netlabelctl -p map list
Configured NetLabel domain mappings (3)
 domain: "_" (IPv4)
   protocol: UNLABELED
 domain: DEFAULT (IPv4)
   protocol: CIPSO, DOI = 3
 domain: DEFAULT (IPv6)
   protocol: UNLABELED

# cat /smack/ambient
_
# cat /proc/$$/attr/smack/current
_
# ping -c1 10.1.95.12
64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.964 ms
# echo foo >/proc/$$/attr/smack/current
# ping -c1 10.1.95.12
64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.956 ms
unknown option 86

# echo 4 >/smack/doi
# echo 3 >/smack/doi

!> [ 214.050395] smk_cipso_doi:691 cipso add rc = -17 # echo 3 >/smack/doi !> [ 249.402261] smk_cipso_doi:678 remove rc = -2 !> [ 249.402261] smk_cipso_doi:691 cipso add rc = -17

# ping -c1 10.1.95.12

!!> ping: 10.1.95.12: Address family for hostname not supported

# echo _ >/proc/$$/attr/smack/current
# ping -c1 10.1.95.12
64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.617 ms

This happens because Smack keeps decommissioned DOIs, fails to re-add them, and consequently refuses to add the “default” domain map:

# netlabelctl -p cipso list
Configured CIPSO mappings (2)
 DOI value : 3
   mapping type : PASS_THROUGH
 DOI value : 4
   mapping type : PASS_THROUGH
# netlabelctl -p map list
Configured NetLabel domain mappings (2)
 domain: "_" (IPv4)
   protocol: UNLABELED

!> (no ipv4 map for default domain here) domain: DEFAULT (IPv6) protocol: UNLABELED

Fix by clearing decommissioned DOI definitions and serializing concurrent DOI updates with a new lock.

Also: - allow /smack/doi to live unconfigured, since adding a map (netlbl_cfg_cipsov4_map_add) may fail. CIPSO_V4_DOI_UNKNOWN(0) indicates the unconfigured DOI - add new DOI before removing the old default map, so the old map remains if the add fails

(2008-02-04, Casey Schaufler)

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{
  "affected": [],
  "aliases": [
    "CVE-2025-71304"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:16:42Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmack: /smack/doi: accept previously used values\n\nWriting to /smack/doi a value that has ever been\nwritten there in the past disables networking for\nnon-ambient labels.\nE.g.\n\n    # cat /smack/doi\n    3\n    # netlabelctl -p cipso list\n    Configured CIPSO mappings (1)\n     DOI value : 3\n       mapping type : PASS_THROUGH\n    # netlabelctl -p map list\n    Configured NetLabel domain mappings (3)\n     domain: \"_\" (IPv4)\n       protocol: UNLABELED\n     domain: DEFAULT (IPv4)\n       protocol: CIPSO, DOI = 3\n     domain: DEFAULT (IPv6)\n       protocol: UNLABELED\n\n    # cat /smack/ambient\n    _\n    # cat /proc/$$/attr/smack/current\n    _\n    # ping -c1 10.1.95.12\n    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.964 ms\n    # echo foo \u003e/proc/$$/attr/smack/current\n    # ping -c1 10.1.95.12\n    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.956 ms\n    unknown option 86\n\n    # echo 4 \u003e/smack/doi\n    # echo 3 \u003e/smack/doi\n!\u003e  [  214.050395] smk_cipso_doi:691 cipso add rc = -17\n    # echo 3 \u003e/smack/doi\n!\u003e  [  249.402261] smk_cipso_doi:678 remove rc = -2\n!\u003e  [  249.402261] smk_cipso_doi:691 cipso add rc = -17\n\n    # ping -c1 10.1.95.12\n!!\u003e ping: 10.1.95.12: Address family for hostname not supported\n\n    # echo _ \u003e/proc/$$/attr/smack/current\n    # ping -c1 10.1.95.12\n    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.617 ms\n\nThis happens because Smack keeps decommissioned DOIs,\nfails to re-add them, and consequently refuses to add\nthe \u201cdefault\u201d domain map:\n\n    # netlabelctl -p cipso list\n    Configured CIPSO mappings (2)\n     DOI value : 3\n       mapping type : PASS_THROUGH\n     DOI value : 4\n       mapping type : PASS_THROUGH\n    # netlabelctl -p map list\n    Configured NetLabel domain mappings (2)\n     domain: \"_\" (IPv4)\n       protocol: UNLABELED\n!\u003e  (no ipv4 map for default domain here)\n     domain: DEFAULT (IPv6)\n       protocol: UNLABELED\n\nFix by clearing decommissioned DOI definitions and\nserializing concurrent DOI updates with a new lock.\n\nAlso:\n- allow /smack/doi to live unconfigured, since\n  adding a map (netlbl_cfg_cipsov4_map_add) may fail.\n  CIPSO_V4_DOI_UNKNOWN(0) indicates the unconfigured DOI\n- add new DOI before removing the old default map,\n  so the old map remains if the add fails\n\n(2008-02-04, Casey Schaufler)",
  "id": "GHSA-hgc7-rqx4-p393",
  "modified": "2026-05-27T15:33:11Z",
  "published": "2026-05-27T15:33:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-71304"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/199452f22d2f74b897fe826f81ec402b0a8461a0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c7ee23dfcd18d80770d8f90f2ab5bb1b2bfd8a3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/33d589ed60ae433b483761987b85e0d24e54584e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5a247a84de0ba44edbbd6be851c8a6b2aa60ff85"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6ec091c5c7eeabd249a7c46813cad1e9f555f859"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8beebb8ad9a003f978e53b06237986588223e15e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb718a3c8181ada679340db34cd61bce48e44749"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f8071500177f38cff38892bd85ac631cc6e010b2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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