af_unix: fix struct pid leaks in OOB support

{
  "id": "f86c84b53a340399f5bbd2ce2a7091374748cb526e8b571456960632640f4d1c",
  "url": "https://osv.dev/vulnerability/CVE-2023-53136",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "af_unix: fix struct pid leaks in OOB support",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: af_unix: fix struct pid leaks in OOB support syzbot reported struct pid leak [1]. Issue is that queue_oob() calls maybe_add_creds() which potentially holds a reference on a pid. But skb->destructor is not set (either directly or by calling unix_scm_to_skb()) This means that subsequent kfree_skb() or consume_skb() would leak this reference. In this fix, I chose to fully support scm even for the OOB message. [1] BUG: memory leak unreferenced object 0xffff8881053e7f80 (size 128): comm \"syz-executor242\", pid 5066, jiffies 4294946079 (age 13.220s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] alloc_pid+0x6a/0x560 kernel/pid.c:180 [] copy_process+0x169f/0x26c0 kernel/fork.c:2285 [] kernel_clone+0xf7/0x610 kernel/fork.c:2684 [] __do_sys_clone+0x7c/0xb0 kernel/fork.c:2825 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd",
    "evidence": "osv:CVE-2023-53136",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.103",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.20",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.2.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-53136",
      "aliases": [
        "CVE-2023-53136"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
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                {
                  "fixed": "a59d6306263c38e5c0592ea4451ca26a0778c947"
                },
                {
                  "fixed": "2aab4b96900272885bc157f8b236abf1cdc02e08"
                }
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            }
          ],
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            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53136.json"
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.15.0"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.16.0"
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                {
                  "fixed": "6.1.20"
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              ]
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.2.0"
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                {
                  "fixed": "6.2.7"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53136.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.414018226Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2aab4b96900272885bc157f8b236abf1cdc02e08",
        "https://git.kernel.org/stable/c/a59d6306263c38e5c0592ea4451ca26a0778c947",
        "https://git.kernel.org/stable/c/ac1968ac399205fda9ee3b18f7de7416cb3a5d0d",
        "https://git.kernel.org/stable/c/f3969427fb06a2c3cd6efd7faab63505cfa76e76",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53136.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53136",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53136.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-53136",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505543,
  "published_at": "2025-05-02T15:56:08.94+00:00"
}