« Volver al listado

CVE-2024-50263

Estado: ModificadaMedia (5.5)—

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

fork: only invoke khugepaged, ksm hooks if no error

There is no reason to invoke these hooks early against an mm that is in an incomplete state.

The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent.

Their placement early in dup_mmap() only appears to have been meaningful for early error checking, and since functionally it'd require a very small allocation to fail (in practice 'too small to fail') that'd only occur in the most dire circumstances, meaning the fork would fail or be OOM'd in any case.

Leer descripción completaMostrar menos

Since both khugepaged and KSM tracking are there to provide optimisations to memory performance rather than critical functionality, it doesn't really matter all that much if, under such dire memory pressure, we fail to register an mm with these.

As a result, we follow the example of commit d2081b2bf819 ("mm: khugepaged: make khugepaged_enter() void function") and make ksm_fork() a void function also.

We only expose the mm to these functions once we are done with them and only if no error occurred in the fork operation.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2024-50263",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "d2406291483775ecddaee929231a39c70c08fda2",
              "lessThan": "3b85aa0da8cd01173b9afd1f70080fbb9576c4b0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d2406291483775ecddaee929231a39c70c08fda2",
              "lessThan": "985da552a98e27096444508ce5d853244019111f",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "include/linux/ksm.h",
            "kernel/fork.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.8",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.11.7",
              "versionType": "semver",
              "lessThanOrEqual": "6.11.*"
            },
            {
              "status": "unaffected",
              "version": "6.12",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "include/linux/ksm.h",
            "kernel/fork.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2024-11-11T14:15:15.473",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/3b85aa0da8cd01173b9afd1f70080fbb9576c4b0",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/985da552a98e27096444508ce5d853244019111f",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://project-zero.issues.chromium.org/issues/373391951",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfork: only invoke khugepaged, ksm hooks if no error\n\nThere is no reason to invoke these hooks early against an mm that is in an\nincomplete state.\n\nThe change in commit d24062914837 (\"fork: use __mt_dup() to duplicate\nmaple tree in dup_mmap()\") makes this more pertinent as we may be in a\nstate where entries in the maple tree are not yet consistent.\n\nTheir placement early in dup_mmap() only appears to have been meaningful\nfor early error checking, and since functionally it'd require a very small\nallocation to fail (in practice 'too small to fail') that'd only occur in\nthe most dire circumstances, meaning the fork would fail or be OOM'd in\nany case.\n\nSince both khugepaged and KSM tracking are there to provide optimisations\nto memory performance rather than critical functionality, it doesn't\nreally matter all that much if, under such dire memory pressure, we fail\nto register an mm with these.\n\nAs a result, we follow the example of commit d2081b2bf819 (\"mm:\nkhugepaged: make khugepaged_enter() void function\") and make ksm_fork() a\nvoid function also.\n\nWe only expose the mm to these functions once we are done with them and\nonly if no error occurred in the fork operation."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fork: solo invocar ganchos khugepaged, ksm si no hay error No hay razón para invocar estos ganchos de manera temprana contra un mm que está en un estado incompleto. El cambio en el commit d24062914837 (\"fork: usar __mt_dup() para duplicar el árbol de maple en dup_mmap()\") hace que esto sea más pertinente ya que podemos estar en un estado donde las entradas en el árbol de maple aún no son consistentes. Su ubicación temprana en dup_mmap() solo parece haber sido significativa para la comprobación temprana de errores, y dado que funcionalmente requeriría una asignación muy pequeña para fallar (en la práctica 'demasiado pequeña para fallar') eso solo ocurriría en las circunstancias más extremas, lo que significa que la bifurcación fallaría o quedaría OOM en cualquier caso. Dado que tanto el seguimiento de khugepaged como el de KSM están ahí para proporcionar optimizaciones al rendimiento de la memoria en lugar de una funcionalidad crítica, en realidad no importa tanto si, bajo una presión de memoria tan extrema, no logramos registrar un mm con estos. Como resultado, seguimos el ejemplo de el commit d2081b2bf819 (\"mm: khugepaged: make khugepaged_enter() void function\") y también hacemos que ksm_fork() sea una función void. Solo exponemos el mm a estas funciones una vez que terminamos con ellas y solo si no ocurrió ningún error en la operación de bifurcación."
    }
  ],
  "lastModified": "2026-08-04T11:21:38.527",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "40C0D9F3-9632-46FE-AA28-8CD73B52DEE7",
              "versionEndExcluding": "6.11.7",
              "versionStartIncluding": "6.8"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "7F361E1D-580F-4A2D-A509-7615F73167A1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "925478D0-3E3D-4E6F-ACD5-09F28D5DF82C"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3C95E234-D335-4B6C-96BF-E2CEBD8654ED"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E0F717D8-3014-4F84-8086-0124B2111379"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "24DBE6C7-2AAE-4818-AED2-E131F153D2FA"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}