CVE-2025-21709 (GCVE-0-2025-21709)
Vulnerability from cvelistv5
Published
2025-02-27 02:07
Modified
2025-05-04 07:19
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: kernel: be more careful about dup_mmap() failures and uprobe registering If a memory allocation fails during dup_mmap(), the maple tree can be left in an unsafe state for other iterators besides the exit path. All the locks are dropped before the exit_mmap() call (in mm/mmap.c), but the incomplete mm_struct can be reached through (at least) the rmap finding the vmas which have a pointer back to the mm_struct. Up to this point, there have been no issues with being able to find an mm_struct that was only partially initialised. Syzbot was able to make the incomplete mm_struct fail with recent forking changes, so it has been proven unsafe to use the mm_struct that hasn't been initialised, as referenced in the link below. Although 8ac662f5da19f ("fork: avoid inappropriate uprobe access to invalid mm") fixed the uprobe access, it does not completely remove the race. This patch sets the MMF_OOM_SKIP to avoid the iteration of the vmas on the oom side (even though this is extremely unlikely to be selected as an oom victim in the race window), and sets MMF_UNSTABLE to avoid other potential users from using a partially initialised mm_struct. When registering vmas for uprobe, skip the vmas in an mm that is marked unstable. Modifying a vma in an unstable mm may cause issues if the mm isn't fully initialised.
References
Impacted products
Vendor Product Version
Linux Linux Version: d2406291483775ecddaee929231a39c70c08fda2
Version: d2406291483775ecddaee929231a39c70c08fda2
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/uprobes.c",
            "kernel/fork.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "da139948aeda677ac09cc0e7d837f8a314de7d55",
              "status": "affected",
              "version": "d2406291483775ecddaee929231a39c70c08fda2",
              "versionType": "git"
            },
            {
              "lessThan": "64c37e134b120fb462fb4a80694bfb8e7be77b14",
              "status": "affected",
              "version": "d2406291483775ecddaee929231a39c70c08fda2",
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/uprobes.c",
            "kernel/fork.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13.2",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkernel: be more careful about dup_mmap() failures and uprobe registering\n\nIf a memory allocation fails during dup_mmap(), the maple tree can be left\nin an unsafe state for other iterators besides the exit path.  All the\nlocks are dropped before the exit_mmap() call (in mm/mmap.c), but the\nincomplete mm_struct can be reached through (at least) the rmap finding\nthe vmas which have a pointer back to the mm_struct.\n\nUp to this point, there have been no issues with being able to find an\nmm_struct that was only partially initialised.  Syzbot was able to make\nthe incomplete mm_struct fail with recent forking changes, so it has been\nproven unsafe to use the mm_struct that hasn\u0027t been initialised, as\nreferenced in the link below.\n\nAlthough 8ac662f5da19f (\"fork: avoid inappropriate uprobe access to\ninvalid mm\") fixed the uprobe access, it does not completely remove the\nrace.\n\nThis patch sets the MMF_OOM_SKIP to avoid the iteration of the vmas on the\noom side (even though this is extremely unlikely to be selected as an oom\nvictim in the race window), and sets MMF_UNSTABLE to avoid other potential\nusers from using a partially initialised mm_struct.\n\nWhen registering vmas for uprobe, skip the vmas in an mm that is marked\nunstable.  Modifying a vma in an unstable mm may cause issues if the mm\nisn\u0027t fully initialised."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-04T07:19:27.199Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/da139948aeda677ac09cc0e7d837f8a314de7d55"
        },
        {
          "url": "https://git.kernel.org/stable/c/64c37e134b120fb462fb4a80694bfb8e7be77b14"
        }
      ],
      "title": "kernel: be more careful about dup_mmap() failures and uprobe registering",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-21709",
    "datePublished": "2025-02-27T02:07:22.452Z",
    "dateReserved": "2024-12-29T08:45:45.752Z",
    "dateUpdated": "2025-05-04T07:19:27.199Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-21709\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-02-27T02:15:14.560\",\"lastModified\":\"2025-02-27T02:15:14.560\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nkernel: be more careful about dup_mmap() failures and uprobe registering\\n\\nIf a memory allocation fails during dup_mmap(), the maple tree can be left\\nin an unsafe state for other iterators besides the exit path.  All the\\nlocks are dropped before the exit_mmap() call (in mm/mmap.c), but the\\nincomplete mm_struct can be reached through (at least) the rmap finding\\nthe vmas which have a pointer back to the mm_struct.\\n\\nUp to this point, there have been no issues with being able to find an\\nmm_struct that was only partially initialised.  Syzbot was able to make\\nthe incomplete mm_struct fail with recent forking changes, so it has been\\nproven unsafe to use the mm_struct that hasn\u0027t been initialised, as\\nreferenced in the link below.\\n\\nAlthough 8ac662f5da19f (\\\"fork: avoid inappropriate uprobe access to\\ninvalid mm\\\") fixed the uprobe access, it does not completely remove the\\nrace.\\n\\nThis patch sets the MMF_OOM_SKIP to avoid the iteration of the vmas on the\\noom side (even though this is extremely unlikely to be selected as an oom\\nvictim in the race window), and sets MMF_UNSTABLE to avoid other potential\\nusers from using a partially initialised mm_struct.\\n\\nWhen registering vmas for uprobe, skip the vmas in an mm that is marked\\nunstable.  Modifying a vma in an unstable mm may cause issues if the mm\\nisn\u0027t fully initialised.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kernel: tenga m\u00e1s cuidado con los fallos de dup_mmap() y el registro de uprobe Si una asignaci\u00f3n de memoria falla durante dup_mmap(), el \u00e1rbol de maple puede quedar en un estado inseguro para otros iteradores adem\u00e1s de la ruta de salida. Todos los bloqueos se eliminan antes de la llamada a exit_mmap() (en mm/mmap.c), pero se puede llegar al mm_struct incompleto a trav\u00e9s de (al menos) el rmap que encuentra los vmas que tienen un puntero de vuelta al mm_struct. Hasta este punto, no ha habido problemas para poder encontrar un mm_struct que solo se haya inicializado parcialmente. Syzbot pudo hacer que el mm_struct incompleto fallara con los cambios de bifurcaci\u00f3n recientes, por lo que se ha demostrado que no es seguro usar el mm_struct que no se ha inicializado, como se hace referencia en el enlace a continuaci\u00f3n. Aunque 8ac662f5da19f (\\\"fork: avoid inappropriate uprobe access to invalid mm\\\") solucion\u00f3 el acceso a uprobe, no elimina por completo la carrera. Este parche establece MMF_OOM_SKIP para evitar la iteraci\u00f3n de las vmas en el lado oom (aunque es extremadamente improbable que se seleccione como v\u00edctima de oom en la ventana de carrera), y establece MMF_UNSTABLE para evitar que otros usuarios potenciales utilicen una mm_struct parcialmente inicializada. Al registrar vmas para uprobe, omite las vmas en un mm que est\u00e9 marcado como inestable. Modificar una vma en un mm inestable puede causar problemas si el mm no est\u00e1 completamente inicializado.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/64c37e134b120fb462fb4a80694bfb8e7be77b14\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/da139948aeda677ac09cc0e7d837f8a314de7d55\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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