CVE-2025-37999 (GCVE-0-2025-37999)
Vulnerability from cvelistv5
Published
2025-05-29 13:15
Modified
2025-05-29 13:15
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: fs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio() If bio_add_folio() fails (because it is full), erofs_fileio_scan_folio() needs to submit the I/O request via erofs_fileio_rq_submit() and allocate a new I/O request with an empty `struct bio`. Then it retries the bio_add_folio() call. However, at this point, erofs_onlinefolio_split() has already been called which increments `folio->private`; the retry will call erofs_onlinefolio_split() again, but there will never be a matching erofs_onlinefolio_end() call. This leaves the folio locked forever and all waiters will be stuck in folio_wait_bit_common(). This bug has been added by commit ce63cb62d794 ("erofs: support unencoded inodes for fileio"), but was practically unreachable because there was room for 256 folios in the `struct bio` - until commit 9f74ae8c9ac9 ("erofs: shorten bvecs[] for file-backed mounts") which reduced the array capacity to 16 folios. It was now trivial to trigger the bug by manually invoking readahead from userspace, e.g.: posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED); This should be fixed by invoking erofs_onlinefolio_split() only after bio_add_folio() has succeeded. This is safe: asynchronous completions invoking erofs_onlinefolio_end() will not unlock the folio because erofs_fileio_scan_folio() is still holding a reference to be released by erofs_onlinefolio_end() at the end.
References
Impacted products
Vendor Product Version
Linux Linux Version: ce63cb62d794c98c7631c2296fa845f2a8d0a4a1
Version: ce63cb62d794c98c7631c2296fa845f2a8d0a4a1
Version: ce63cb62d794c98c7631c2296fa845f2a8d0a4a1
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/erofs/fileio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "61e0fc3312309867e5a3495329dad0286d2a5703",
              "status": "affected",
              "version": "ce63cb62d794c98c7631c2296fa845f2a8d0a4a1",
              "versionType": "git"
            },
            {
              "lessThan": "c26076197df348c84cc23e5962d61902e072a0f5",
              "status": "affected",
              "version": "ce63cb62d794c98c7631c2296fa845f2a8d0a4a1",
              "versionType": "git"
            },
            {
              "lessThan": "bbfe756dc3062c1e934f06e5ba39c239aa953b92",
              "status": "affected",
              "version": "ce63cb62d794c98c7631c2296fa845f2a8d0a4a1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/erofs/fileio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.29",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.14.*",
              "status": "unaffected",
              "version": "6.14.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.15",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.29",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14.7",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()\n\nIf bio_add_folio() fails (because it is full),\nerofs_fileio_scan_folio() needs to submit the I/O request via\nerofs_fileio_rq_submit() and allocate a new I/O request with an empty\n`struct bio`.  Then it retries the bio_add_folio() call.\n\nHowever, at this point, erofs_onlinefolio_split() has already been\ncalled which increments `folio-\u003eprivate`; the retry will call\nerofs_onlinefolio_split() again, but there will never be a matching\nerofs_onlinefolio_end() call.  This leaves the folio locked forever\nand all waiters will be stuck in folio_wait_bit_common().\n\nThis bug has been added by commit ce63cb62d794 (\"erofs: support\nunencoded inodes for fileio\"), but was practically unreachable because\nthere was room for 256 folios in the `struct bio` - until commit\n9f74ae8c9ac9 (\"erofs: shorten bvecs[] for file-backed mounts\") which\nreduced the array capacity to 16 folios.\n\nIt was now trivial to trigger the bug by manually invoking readahead\nfrom userspace, e.g.:\n\n posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED);\n\nThis should be fixed by invoking erofs_onlinefolio_split() only after\nbio_add_folio() has succeeded.  This is safe: asynchronous completions\ninvoking erofs_onlinefolio_end() will not unlock the folio because\nerofs_fileio_scan_folio() is still holding a reference to be released\nby erofs_onlinefolio_end() at the end."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-29T13:15:56.825Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/61e0fc3312309867e5a3495329dad0286d2a5703"
        },
        {
          "url": "https://git.kernel.org/stable/c/c26076197df348c84cc23e5962d61902e072a0f5"
        },
        {
          "url": "https://git.kernel.org/stable/c/bbfe756dc3062c1e934f06e5ba39c239aa953b92"
        }
      ],
      "title": "fs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37999",
    "datePublished": "2025-05-29T13:15:56.825Z",
    "dateReserved": "2025-04-16T04:51:23.976Z",
    "dateUpdated": "2025-05-29T13:15:56.825Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-37999\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-05-29T14:15:36.597\",\"lastModified\":\"2025-05-29T14:29:50.247\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nfs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()\\n\\nIf bio_add_folio() fails (because it is full),\\nerofs_fileio_scan_folio() needs to submit the I/O request via\\nerofs_fileio_rq_submit() and allocate a new I/O request with an empty\\n`struct bio`.  Then it retries the bio_add_folio() call.\\n\\nHowever, at this point, erofs_onlinefolio_split() has already been\\ncalled which increments `folio-\u003eprivate`; the retry will call\\nerofs_onlinefolio_split() again, but there will never be a matching\\nerofs_onlinefolio_end() call.  This leaves the folio locked forever\\nand all waiters will be stuck in folio_wait_bit_common().\\n\\nThis bug has been added by commit ce63cb62d794 (\\\"erofs: support\\nunencoded inodes for fileio\\\"), but was practically unreachable because\\nthere was room for 256 folios in the `struct bio` - until commit\\n9f74ae8c9ac9 (\\\"erofs: shorten bvecs[] for file-backed mounts\\\") which\\nreduced the array capacity to 16 folios.\\n\\nIt was now trivial to trigger the bug by manually invoking readahead\\nfrom userspace, e.g.:\\n\\n posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED);\\n\\nThis should be fixed by invoking erofs_onlinefolio_split() only after\\nbio_add_folio() has succeeded.  This is safe: asynchronous completions\\ninvoking erofs_onlinefolio_end() will not unlock the folio because\\nerofs_fileio_scan_folio() is still holding a reference to be released\\nby erofs_onlinefolio_end() at the end.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fs/erofs/fileio: llamar a erofs_onlinefolio_split() despu\u00e9s de bio_add_folio(). Si bio_add_folio() falla (porque est\u00e1 lleno), erofs_fileio_scan_folio() debe enviar la solicitud de E/S mediante erofs_fileio_rq_submit() y asignar una nueva solicitud de E/S con un `struct bio` vac\u00edo. Luego, vuelve a intentar la llamada a bio_add_folio(). Sin embargo, en este punto, ya se ha llamado a erofs_onlinefolio_split(), lo que incrementa `folio-\u0026gt;private`; el reintento llamar\u00e1 a erofs_onlinefolio_split() de nuevo, pero nunca habr\u00e1 una llamada erofs_onlinefolio_end() coincidente. Esto deja el folio bloqueado para siempre y todos los que esperan quedar\u00e1n atascados en folio_wait_bit_common(). Este error se a\u00f1adi\u00f3 con el commit ce63cb62d794 (\\\"erofs: compatibilidad con inodos no codificados para fileio\\\"), pero era pr\u00e1cticamente imposible de solucionar porque hab\u00eda espacio para 256 folios en la estructura `struct bio`, hasta el commit 9f74ae8c9ac9 (\\\"erofs: acortar bvecs[] para montajes con respaldo de archivo\\\"), que redujo la capacidad del array a 16 folios. Ahora era f\u00e1cil activar el error invocando manualmente la lectura anticipada desde el espacio de usuario, por ejemplo: posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED); Esto deber\u00eda solucionarse invocando erofs_onlinefolio_split() solo despu\u00e9s de que bio_add_folio() se haya ejecutado correctamente. Esto es seguro: las finalizaciones asincr\u00f3nicas que invocan erofs_onlinefolio_end() no desbloquear\u00e1n el folio porque erofs_fileio_scan_folio() todav\u00eda contiene una referencia que erofs_onlinefolio_end() liberar\u00e1 al final.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/61e0fc3312309867e5a3495329dad0286d2a5703\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/bbfe756dc3062c1e934f06e5ba39c239aa953b92\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c26076197df348c84cc23e5962d61902e072a0f5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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