{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-40112",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-40112"
  ],
  "published": "2025-11-12T10:24:04Z",
  "summary": "sparc: fix accurate exception reporting in copy_{from_to}_user for Niagara",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsparc: fix accurate exception reporting in copy_{from_to}_user for Niagara\n\nThe referenced commit introduced exception handlers on user-space memory\nreferences in copy_from_user and copy_to_user. These handlers return from\nthe respective function and calculate the remaining bytes left to copy\nusing the current register contents. This commit fixes a couple of bad\ncalculations and a broken epilogue in the exception handlers. This will\nprevent crashes and ensure correct return values of copy_from_user and\ncopy_to_user in the faulting case. The behaviour of memcpy stays unchanged.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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": "6.1.156",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-40112"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/05440320ea3e249d5f984918f2bf51210c1a7c03"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7823fc4d8ab5e57f8db7806ff2530c03c166c4bb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/37547d8e6eba87507279ee3dfddfd9dc46335454"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a365ee556e45f780ee322b349a06efdad0c1458f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8cdeb5e482d3fdce7e825444b6ca3865e24c0228"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a90ce516a73dbe087f9bf3dbf311301a58d125c6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/088c5098ec6d6b0396edfbf3dad3e81de8469c1c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0b67c8fc10b13a9090340c5f8a37d308f4e1571c"
    }
  ],
  "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": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The fault must occur on the calling process's own user-space buffer during a syscall, so the attacker needs local execution to issue syscalls with a deliberately unmapped/PROT_NONE user address. No remote or adjacent-network path can drive copy_from_user/copy_to_user faults on behalf of another task.\nAC:L - The attacker fully controls every precondition \u2014 mmap a buffer, punch a PROT_NONE/unmapped page, and pick the length and alignment that steer the copy into the buggy 16-byte or unaligned loop; the broken __restore_asi epilogue is hit on every fault regardless. No race, no memory-layout luck, and the Niagara copy routines are auto-selected by CPU type with no special kernel config.\nPR:L - Any unprivileged local user can pass a partially-invalid user pointer to ordinary syscalls such as read(), write(), sendmsg() or ioctl(); no capability, namespace or filesystem privilege is involved.\nUI:N - The attacking process triggers the faulting copy entirely on its own via a syscall; no action by another user or administrator is needed.\nS:U - The corruption is confined to the kernel of the running system \u2014 no hypervisor, IOMMU or sandbox boundary is crossed.\nC:H - The under-reported remainder leaves 8\u201316 bytes of the kernel destination buffer unzeroed by _inline_copy_from_user()'s memset and treated as valid user data, repeatedly leaking stale kernel heap/stack contents into buffers that syscalls process or write back; the missing register-window restore additionally exposes kernel pointers as the copy's return value.\nI:H - The dead `restore` makes raw_copy_from_user return a destination pointer instead of a byte count, so memset(to + (n - res), 0, res) becomes an unbounded out-of-bounds kernel write, and the unpopped register window leaves the caller with a corrupted %sp/%fp and a wrong saved return address \u2014 memory corruption with attacker-influenced pointers and hijackable control flow.\nA:H - Returning without restoring the register window desynchronizes the entire SPARC window stack and the caller's stack frame, and the giant memset length guarantees a wild write; the result is an immediate kernel oops/panic on every triggered fault, trivially repeatable by an unprivileged user."
    }
  }
}