{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-38257",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-38257"
  ],
  "published": "2025-07-09T10:43:51Z",
  "summary": "s390/pkey: Prevent overflow in size calculation for memdup_user()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/pkey: Prevent overflow in size calculation for memdup_user()\n\nNumber of apqn target list entries contained in 'nr_apqns' variable is\ndetermined by userspace via an ioctl call so the result of the product in\ncalculation of size passed to memdup_user() may overflow.\n\nIn this case the actual size of the allocated area and the value\ndescribing it won't be in sync leading to various types of unpredictable\nbehaviour later.\n\nUse a proper memdup_array_user() helper which returns an error if an\noverflow is detected. Note that it is different from when nr_apqns is\ninitially zero - that case is considered valid and should be handled in\nsubsequent pkey_handler implementations.\n\nFound by Linux Verification Center (linuxtesting.org).",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.143",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-38257"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ad1bdd24a02d5a8d119af8e4cd50933780a6d29f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/faa1ab4a23c42e34dc000ef4977b751d94d5148c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/88f3869649edbc4a13f6c2877091f81cd5a50f05"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f855b119e62b004a5044ed565f2a2b368c4d3f16"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/73483ca7e07a5e39bdf612eec9d3d293e8bef649"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7360ee47599af91a1d5f4e74d635d9408a54e489"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.3,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable code is reached only through ioctl calls on the /dev/pkey misc device node; there is no network, adjacent-network, or remote-peer data path into `_copy_apqns_from_user()`. The in-kernel API (`pkey_key2protkey`) and sysfs paths always pass a NULL apqn list with count 0.\nAC:L - `apqn_entries` is a plain u32 field copied directly from the ioctl argument struct, so the attacker sets the value outright in a single deterministic ioctl call. No race, no memory-layout dependency, and no condition outside the attacker's control.\nPR:L - The pkey miscdevice is registered with `.mode = 0666`, making it world read/write, and neither `pkey_unlocked_ioctl()` nor any of the four reachable sub-handlers performs a `capable()` or `CAP_*` check. Any local unprivileged user on an s390 system with CONFIG_PKEY enabled (standard in distro mainframe kernels) can trigger it.\nUI:N - The attacker issues the ioctl directly from their own process; no victim action, mount, or file open by another user is involved.\nS:U - The undersized allocation and the resulting out-of-bounds access are both in kernel heap memory within the same security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The size/count desynchronization causes the CCA handlers to walk `apqns[i]` far past the end of an attacker-sized kmalloc buffer, an unbounded slab out-of-bounds read rather than a few-byte overread. The disclosed heap contents are consumed as card/domain selectors, exposing adjacent kernel object data.\nI:L - All handler signatures take `const struct pkey_apqn *apqns`, so the desynchronized buffer is only ever read \u2014 there is no out-of-bounds write or control-flow hijack primitive. Integrity impact is limited to out-of-bounds heap values steering crypto-adapter requests to attacker-uncontrolled card/domain pairs.\nA:H - Iterating up to billions of entries past a small kmalloc'd buffer reliably reaches unmapped memory, producing a kernel oops/panic, and the loop contains no `cond_resched()` so it can also stall the CPU. Any unprivileged local user can repeat this at will."
    }
  }
}