ghsa-pv37-x56g-xg2m
Vulnerability from github
Published
2025-09-05 18:31
Modified
2025-09-05 18:31
Details

In the Linux kernel, the following vulnerability has been resolved:

parisc: Revise __get_user() to probe user read access

Because of the way read access support is implemented, read access interruptions are only triggered at privilege levels 2 and 3. The kernel executes at privilege level 0, so __get_user() never triggers a read access interruption (code 26). Thus, it is currently possible for user code to access a read protected address via a system call.

Fix this by probing read access rights at privilege level 3 (PRIV_USER) and setting __gu_err to -EFAULT (-14) if access isn't allowed.

Note the cmpiclr instruction does a 32-bit compare because COND macro doesn't work inside asm.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-39716"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-05T18:15:49Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nparisc: Revise __get_user() to probe user read access\n\nBecause of the way read access support is implemented, read access\ninterruptions are only triggered at privilege levels 2 and 3. The\nkernel executes at privilege level 0, so __get_user() never triggers\na read access interruption (code 26). Thus, it is currently possible\nfor user code to access a read protected address via a system call.\n\nFix this by probing read access rights at privilege level 3 (PRIV_USER)\nand setting __gu_err to -EFAULT (-14) if access isn\u0027t allowed.\n\nNote the cmpiclr instruction does a 32-bit compare because COND macro\ndoesn\u0027t work inside asm.",
  "id": "GHSA-pv37-x56g-xg2m",
  "modified": "2025-09-05T18:31:27Z",
  "published": "2025-09-05T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39716"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/28a9b71671fb4a2993ef85b8ef6f117ea63894fe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4c981077255acc2ed5b3df6e8dd0125c81b626a9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/741b163e440683195b8fd4fc8495fcd0105c6ab7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/89f686a0fb6e473a876a9a60a13aec67a62b9a7e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f410ef9a032caf98117256b22139c31342d7bb06"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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