tipc: fix a null-ptr-deref in tipc_topsrv_accept

{
  "id": "8a31616bba912a182f5ab44e061ce3e13f2d0df8a976b7f30769608179d1d22f",
  "url": "https://osv.dev/vulnerability/CVE-2022-50555",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tipc: fix a null-ptr-deref in tipc_topsrv_accept",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tipc: fix a null-ptr-deref in tipc_topsrv_accept syzbot found a crash in tipc_topsrv_accept: KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] Workqueue: tipc_rcv tipc_topsrv_accept RIP: 0010:kernel_accept+0x22d/0x350 net/socket.c:3487 Call Trace: tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 It was caused by srv->listener that might be set to null by tipc_topsrv_stop() in net .exit whereas it's still used in tipc_topsrv_accept() worker. srv->listener is protected by srv->idr_lock in tipc_topsrv_stop(), so add a check for srv->listener under srv->idr_lock in tipc_topsrv_accept() to avoid the null-ptr-deref. To ensure the lsock is not released during the tipc_topsrv_accept(), move sock_release() after tipc_topsrv_work_stop() where it's waiting until the tipc_topsrv_accept worker to be done. Note that sk_callback_lock is used to protect sk->sk_user_data instead of srv->listener, and it should check srv in tipc_topsrv_listener_data_ready() instead. This also ensures that no more tipc_topsrv_accept worker will be started after tipc_conn_close() is called in tipc_topsrv_stop() where it sets sk->sk_user_data to null.",
    "evidence": "osv:CVE-2022-50555",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.19.264",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.4.223",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.153",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.77",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.0.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2022-50555",
      "aliases": [
        "CVE-2022-50555"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
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                {
                  "fixed": "24b129aed8730e48f47d852d58d76825ab6f407c"
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                {
                  "fixed": "32a3d4660b34ce49ac0162338ebe362098e2f5df"
                },
                {
                  "fixed": "7a939503fc32bff4ed60800b73ff7fbb4aea2142"
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                {
                  "fixed": "cedb41664e27b2cae7e21487f1bee22dcd84037d"
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                {
                  "fixed": "82cb4e4612c633a9ce320e1773114875604a3cce"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50555.json"
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "4.17.0"
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                  "fixed": "4.19.264"
                }
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            {
              "type": "ECOSYSTEM",
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50555.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.536084621Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/24b129aed8730e48f47d852d58d76825ab6f407c",
        "https://git.kernel.org/stable/c/32a3d4660b34ce49ac0162338ebe362098e2f5df",
        "https://git.kernel.org/stable/c/7a939503fc32bff4ed60800b73ff7fbb4aea2142",
        "https://git.kernel.org/stable/c/82cb4e4612c633a9ce320e1773114875604a3cce",
        "https://git.kernel.org/stable/c/ce69bdac2310152bb70845024d5d704c52aabfc3",
        "https://git.kernel.org/stable/c/cedb41664e27b2cae7e21487f1bee22dcd84037d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50555.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-50555",
        "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/2022/50xxx/CVE-2022-50555.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-50555",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 520127,
  "published_at": "2025-10-07T15:21:16.179+00:00"
}