fkie_cve-2024-35985
Vulnerability from fkie_nvd
Published
2024-05-20 10:15
Modified
2025-01-16 16:43
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: sched/eevdf: Prevent vlag from going out of bounds in reweight_eevdf() It was possible to have pick_eevdf() return NULL, which then causes a NULL-deref. This turned out to be due to entity_eligible() returning falsely negative because of a s64 multiplcation overflow. Specifically, reweight_eevdf() computes the vlag without considering the limit placed upon vlag as update_entity_lag() does, and then the scaling multiplication (remember that weight is 20bit fixed point) can overflow. This then leads to the new vruntime being weird which then causes the above entity_eligible() to go side-ways and claim nothing is eligible. Thus limit the range of vlag accordingly. All this was quite rare, but fatal when it does happen.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/06f27e6d7bf0abf54488259ef36bbf0e1fccb35cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1560d1f6eb6b398bddd80c16676776c0325fe5fePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/470d347b14b0ecffa9b39cf8f644fa2351db3efbPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/06f27e6d7bf0abf54488259ef36bbf0e1fccb35cPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/1560d1f6eb6b398bddd80c16676776c0325fe5fePatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/470d347b14b0ecffa9b39cf8f644fa2351db3efbPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.9
linux linux_kernel 6.9
linux linux_kernel 6.9
linux linux_kernel 6.9
linux linux_kernel 6.9


To clipboard 

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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/eevdf: Prevent vlag from going out of bounds in reweight_eevdf()\n\nIt was possible to have pick_eevdf() return NULL, which then causes a\nNULL-deref. This turned out to be due to entity_eligible() returning\nfalsely negative because of a s64 multiplcation overflow.\n\nSpecifically, reweight_eevdf() computes the vlag without considering\nthe limit placed upon vlag as update_entity_lag() does, and then the\nscaling multiplication (remember that weight is 20bit fixed point) can\noverflow. This then leads to the new vruntime being weird which then\ncauses the above entity_eligible() to go side-ways and claim nothing\nis eligible.\n\nThus limit the range of vlag accordingly.\n\nAll this was quite rare, but fatal when it does happen."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: sched/eevdf: evita que vlag se salga de los l\u00edmites en reweight_eevdf(). Era posible que pick_eevdf() devolviera NULL, lo que luego causa un NULL-deref. Esto result\u00f3 ser debido a que entidad_eligible() devolvi\u00f3 un resultado falso negativo debido a un desbordamiento de multiplicaci\u00f3n s64. Espec\u00edficamente, reweight_eevdf() calcula el vlag sin considerar el l\u00edmite impuesto a vlag como lo hace update_entity_lag(), y luego la multiplicaci\u00f3n de escala (recuerde que el peso es un punto fijo de 20 bits) puede desbordarse. Esto luego lleva a que el nuevo vruntime sea extra\u00f1o, lo que luego hace que la entidad_eligible() anterior se desv\u00ede y afirme que nada es elegible. Por lo tanto, limite el rango de vlag en consecuencia. Todo esto fue bastante raro, pero fatal cuando sucede."
    }
  ],
  "id": "CVE-2024-35985",
  "lastModified": "2025-01-16T16:43:59.487",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2024-05-20T10:15:12.920",
  "references": [
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      "tags": [
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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