smc: Fix various oops due to inet_sock type confusion.

{
  "id": "3c7606cee62bc7293d0579fa11ccd860fbcf148afe092296f2c36f6597212bbe",
  "url": "https://osv.dev/vulnerability/CVE-2025-38475",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "smc: Fix various oops due to inet_sock type confusion.",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: smc: Fix various oops due to inet_sock type confusion. syzbot reported weird splats [0][1] in cipso_v4_sock_setattr() while freeing inet_sk(sk)->inet_opt. The address was freed multiple times even though it was read-only memory. cipso_v4_sock_setattr() did nothing wrong, and the root cause was type confusion. The cited commit made it possible to create smc_sock as an INET socket. The issue is that struct smc_sock does not have struct inet_sock as the first member but hijacks AF_INET and AF_INET6 sk_family, which confuses various places. In this case, inet_sock.inet_opt was actually smc_sock.clcsk_data_ready(), which is an address of a function in the text segment. $ pahole -C inet_sock vmlinux struct inet_sock { ... struct ip_options_rcu * inet_opt; /* 784 8 */ $ pahole -C smc_sock vmlinux struct smc_sock { ... void (*clcsk_data_ready)(struct sock *); /* 784 8 */ The same issue for another field was reported before. [2][3] At that time, an ugly hack was suggested [4], but it makes both INET and SMC code error-prone and hard to change. Also, yet another variant was fixed by a hacky commit 98d4435efcbf3 (\"net/smc: prevent NULL pointer dereference in txopt_get\"). Instead of papering over the root cause by such hacks, we should not allow non-INET socket to reuse the INET infra. Let's add inet_sock as the first member of smc_sock. [0]: kvfree_call_rcu(): Double-freed call. rcu_head 000000006921da73 WARNING: CPU: 0",
    "evidence": "osv:CVE-2025-38475",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.15.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-38475",
      "aliases": [
        "CVE-2025-38475"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
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              "type": "ECOSYSTEM",
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                  "introduced": "6.11.0"
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:44.883922483Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/5b02e397929e5b13b969ef1f8e43c7951e2864f5",
        "https://git.kernel.org/stable/c/60ada4fe644edaa6c2da97364184b0425e8aeaf5",
        "https://git.kernel.org/stable/c/67a167a6b8b45607bc34aa541d1c75097d18d460",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38475.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-38475",
        "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/2025/38xxx/CVE-2025-38475.json"
      }
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    "related_cves": [
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        "value": "CVE-2025-38475",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 512592,
  "published_at": "2025-07-28T11:21:36.293+00:00"
}