tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.

{
  "id": "e650fa85954d8bd6020a168d2574c3a0700d3986f548180504ff79f7c76901a4",
  "url": "https://osv.dev/vulnerability/CVE-2025-39913",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork. syzbot reported the splat below. [0] The repro does the following: 1. Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes) 2. Attach the prog to a SOCKMAP 3. Add a socket to the SOCKMAP 4. Activate fault injection 5. Send data less than cork_bytes At 5., the data is carried over to the next sendmsg() as it is smaller than the cork_bytes specified by bpf_msg_cork_bytes(). Then, tcp_bpf_send_verdict() tries to allocate psock->cork to hold the data, but this fails silently due to fault injection + __GFP_NOWARN. If the allocation fails, we need to revert the sk->sk_forward_alloc change done by sk_msg_alloc(). Let's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate psock->cork. The \"*copied\" also needs to be updated such that a proper error can be returned to the caller, sendmsg. It fails to allocate psock->cork. Nothing has been corked so far, so this patch simply sets \"*copied\" to 0. [0]: WARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983 Modules linked in: CPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156 Code: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f",
    "evidence": "osv:CVE-2025-39913",
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    "severity": "unknown",
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      "modified": "2026-10-28T02:30:22.044052669Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-253495.html",
        "https://git.kernel.org/stable/c/05366527f44cf4b884f3d9462ae8009be9665856",
        "https://git.kernel.org/stable/c/08f58d10f5abf11d297cc910754922498c921f91",
        "https://git.kernel.org/stable/c/539920180c55f5e13a2488a2339f94e6b8cb69e0",
        "https://git.kernel.org/stable/c/66bcb04a441fbf15d66834b7e3eefb313dd750c8",
        "https://git.kernel.org/stable/c/7429b8b9bfbc276fd304fbaebc405f46b421fedf",
        "https://git.kernel.org/stable/c/9c2a6456bdf9794474460d885c359b6c4522d6e3",
        "https://git.kernel.org/stable/c/a3967baad4d533dc254c31e0d221e51c8d223d58",
        "https://git.kernel.org/stable/c/de89e58368f8f07df005ecc1c86ad94898a999f2",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39913.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-39913",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
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        "value": "CVE-2025-39913",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 488355,
  "published_at": "2025-10-01T07:44:36.244+00:00"
}