nvme-tcp: check the data direction of a C2HData PDU

{
  "id": "6d500409da1bc976ff0b9a7d288f86e47f926b64b034310953f52b0c5010af56",
  "url": "https://osv.dev/vulnerability/CVE-2026-89973",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nvme-tcp: check the data direction of a C2HData PDU",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: check the data direction of a C2HData PDU nvme_tcp_handle_c2h_data() finds the request by command id and checks that it has a payload, but it does not check that the command asked for data to be read. A controller that answers a write command with C2HData therefore reaches nvme_tcp_recv_data(), where _copy_to_iter() hits WARN_ON_ONCE(i->data_source) and returns 0. The receive path turns that into -EFAULT and resets the controller. No data is copied, so this is not memory corruption. What a controller gets is a kernel warning it can raise at will, which is fatal on a host booted with panic_on_warn. The send path already knows the direction - it consults rq_data_dir() when it builds a command - and nvme_tcp_handle_r2t() checks the length and the offset of the request it names. The C2HData path does not check the direction at all. Reject a C2HData PDU whose command is not a read. Rejecting it fails the command and resets the controller, as the neighbouring check in this function does; what goes away is the warning. [ 6.885580] ------------[ cut here ]------------ [ 6.886457] WARNING: lib/iov_iter.c:193 at _copy_to_iter+0x289/0x1330, CPU#0: kworker/0:1H/71 [ 6.888137] CPU: 0 UID: 0 PID: 71 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMETCP-gf5098b6bae76 #1 PREEMPT(lazy) [ 6.891165] Workqueue: nvme_tcp_wq nvme_tcp_io_work [ 6.891875] RIP: 0010:_copy_to_iter+0x289/0x1330 [ 6.903739] Call Trace: [ 6.904085] ",
    "evidence": "osv:CVE-2026-89973",
    "products": [
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        "prerequisites": [],
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    "severity": "high",
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      "metrics": [
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          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H"
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      "modified": "2026-10-28T02:30:41.552129751Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0673a2affe45ca76b60de31a83c67b1e60f81bde",
        "https://git.kernel.org/stable/c/5b115d932f6e769ac80783fb18edd21b0aed256e",
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        "https://git.kernel.org/stable/c/980d990f3c0560d7dfbfbf14699651fdf02f26ee",
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        "https://git.kernel.org/stable/c/f83af377c148f6ad94b41c0e8313f12adf45e1c1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89973.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89973",
        "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/2026/89xxx/CVE-2026-89973.json"
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        "value": "CVE-2026-89973",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 509232,
  "published_at": "2026-09-16T10:32:52.409+00:00"
}