HID: core: Harden s32ton() against conversion to 0 bits

{
  "id": "4c9b4fa4b8e624ad39ea43d8988998bf6c49321d5321a31d9c93554abb208ab5",
  "url": "https://osv.dev/vulnerability/CVE-2025-38556",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "HID: core: Harden s32ton() against conversion to 0 bits",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: HID: core: Harden s32ton() against conversion to 0 bits Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does.",
    "evidence": "osv:CVE-2025-38556",
    "products": [
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        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
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            "value": "5.10.248",
            "evidence": "/affected/1/ranges"
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    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-38556",
      "aliases": [
        "CVE-2025-38556"
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:50.799385651Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/3c86548a20d7bc2861aa4de044991a327bebad1a",
        "https://git.kernel.org/stable/c/6cdf6c708717c5c6897d0800a1793e83757c7491",
        "https://git.kernel.org/stable/c/810189546cb6c8f36443ed091d91f1f5d2fc2ec7",
        "https://git.kernel.org/stable/c/865ad8469fa24de1559f247d9426ab01e5ce3a56",
        "https://git.kernel.org/stable/c/8b4a94b1510f6a46ec48494b52ee8f67eb4fc836",
        "https://git.kernel.org/stable/c/a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd",
        "https://git.kernel.org/stable/c/d3b504146c111548ab60b6ef7aad00bfb1db05a2",
        "https://git.kernel.org/stable/c/eeeaba737919bdce9885e2a00ac2912f61a3684d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38556.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-38556",
        "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-2025-38556.json"
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      {
        "value": "CVE-2025-38556",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 519129,
  "published_at": "2025-08-19T17:02:34.929+00:00"
}