fkie_cve-2024-49888
Vulnerability from fkie_nvd
Published
2024-10-21 18:15
Modified
2024-11-13 14:54
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: bpf: Fix a sdiv overflow issue Zac Ecob reported a problem where a bpf program may cause kernel crash due to the following error: Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI The failure is due to the below signed divide: LLONG_MIN/-1 where LLONG_MIN equals to -9,223,372,036,854,775,808. LLONG_MIN/-1 is supposed to give a positive number 9,223,372,036,854,775,808, but it is impossible since for 64-bit system, the maximum positive number is 9,223,372,036,854,775,807. On x86_64, LLONG_MIN/-1 will cause a kernel exception. On arm64, the result for LLONG_MIN/-1 is LLONG_MIN. Further investigation found all the following sdiv/smod cases may trigger an exception when bpf program is running on x86_64 platform: - LLONG_MIN/-1 for 64bit operation - INT_MIN/-1 for 32bit operation - LLONG_MIN%-1 for 64bit operation - INT_MIN%-1 for 32bit operation where -1 can be an immediate or in a register. On arm64, there are no exceptions: - LLONG_MIN/-1 = LLONG_MIN - INT_MIN/-1 = INT_MIN - LLONG_MIN%-1 = 0 - INT_MIN%-1 = 0 where -1 can be an immediate or in a register. Insn patching is needed to handle the above cases and the patched codes produced results aligned with above arm64 result. The below are pseudo codes to handle sdiv/smod exceptions including both divisor -1 and divisor 0 and the divisor is stored in a register. sdiv: tmp = rX tmp += 1 /* [-1, 0] -> [0, 1] if tmp >(unsigned) 1 goto L2 if tmp == 0 goto L1 rY = 0 L1: rY = -rY; goto L3 L2: rY /= rX L3: smod: tmp = rX tmp += 1 /* [-1, 0] -> [0, 1] if tmp >(unsigned) 1 goto L1 if tmp == 1 (is64 ? goto L2 : goto L3) rY = 0; goto L2 L1: rY %= rX L2: goto L4 // only when !is64 L3: wY = wY // only when !is64 L4: [1] https://lore.kernel.org/bpf/tPJLTEh7S_DxFEqAI2Ji5MBSoZVg7_G-Py2iaZpAaWtM961fFTWtsnlzwvTbzBzaUzwQAoNATXKUlt0LZOFgnDcIyKCswAnAGdUF3LBrhGQ=@protonmail.com/
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4902a6a0dc593c82055fc8c9ada371bafe26c9ccPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7dd34d7b7dcf9309fc6224caf4dd5b35bedddcb7Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d22e45a369afc7c28f11acfa5b5e8e478227ca5dPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *


To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "652638C5-5F25-4DF3-AD42-DD3252A97152",
              "versionEndExcluding": "6.10.14",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "54D9C704-D679-41A7-9C40-10A6B1E7FFE9",
              "versionEndExcluding": "6.11.3",
              "versionStartIncluding": "6.11",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix a sdiv overflow issue\n\nZac Ecob reported a problem where a bpf program may cause kernel crash due\nto the following error:\n  Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI\n\nThe failure is due to the below signed divide:\n  LLONG_MIN/-1 where LLONG_MIN equals to -9,223,372,036,854,775,808.\nLLONG_MIN/-1 is supposed to give a positive number 9,223,372,036,854,775,808,\nbut it is impossible since for 64-bit system, the maximum positive\nnumber is 9,223,372,036,854,775,807. On x86_64, LLONG_MIN/-1 will\ncause a kernel exception. On arm64, the result for LLONG_MIN/-1 is\nLLONG_MIN.\n\nFurther investigation found all the following sdiv/smod cases may trigger\nan exception when bpf program is running on x86_64 platform:\n  - LLONG_MIN/-1 for 64bit operation\n  - INT_MIN/-1 for 32bit operation\n  - LLONG_MIN%-1 for 64bit operation\n  - INT_MIN%-1 for 32bit operation\nwhere -1 can be an immediate or in a register.\n\nOn arm64, there are no exceptions:\n  - LLONG_MIN/-1 = LLONG_MIN\n  - INT_MIN/-1 = INT_MIN\n  - LLONG_MIN%-1 = 0\n  - INT_MIN%-1 = 0\nwhere -1 can be an immediate or in a register.\n\nInsn patching is needed to handle the above cases and the patched codes\nproduced results aligned with above arm64 result. The below are pseudo\ncodes to handle sdiv/smod exceptions including both divisor -1 and divisor 0\nand the divisor is stored in a register.\n\nsdiv:\n      tmp = rX\n      tmp += 1 /* [-1, 0] -\u003e [0, 1]\n      if tmp \u003e(unsigned) 1 goto L2\n      if tmp == 0 goto L1\n      rY = 0\n  L1:\n      rY = -rY;\n      goto L3\n  L2:\n      rY /= rX\n  L3:\n\nsmod:\n      tmp = rX\n      tmp += 1 /* [-1, 0] -\u003e [0, 1]\n      if tmp \u003e(unsigned) 1 goto L1\n      if tmp == 1 (is64 ? goto L2 : goto L3)\n      rY = 0;\n      goto L2\n  L1:\n      rY %= rX\n  L2:\n      goto L4  // only when !is64\n  L3:\n      wY = wY  // only when !is64\n  L4:\n\n  [1] https://lore.kernel.org/bpf/tPJLTEh7S_DxFEqAI2Ji5MBSoZVg7_G-Py2iaZpAaWtM961fFTWtsnlzwvTbzBzaUzwQAoNATXKUlt0LZOFgnDcIyKCswAnAGdUF3LBrhGQ=@protonmail.com/"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: soluciona un problema de desbordamiento de sdiv Zac Ecob inform\u00f3 de un problema en el que un programa bpf puede provocar un fallo del kernel debido al siguiente error: Oops: error de divisi\u00f3n: 0000 [#1] PREEMPT SMP KASAN PTI El fallo se debe a la siguiente divisi\u00f3n con signo: LLONG_MIN/-1 donde LLONG_MIN equivale a -9.223.372.036.854.775.808. Se supone que LLONG_MIN/-1 da un n\u00famero positivo 9.223.372.036.854.775.808, pero es imposible ya que para sistemas de 64 bits, el n\u00famero positivo m\u00e1ximo es 9.223.372.036.854.775.807. En x86_64, LLONG_MIN/-1 provocar\u00e1 una excepci\u00f3n del kernel. En arm64, el resultado para LLONG_MIN/-1 es LLONG_MIN. Una investigaci\u00f3n m\u00e1s profunda encontr\u00f3 que todos los siguientes casos de sdiv/smod pueden activar una excepci\u00f3n cuando el programa bpf se ejecuta en la plataforma x86_64: - LLONG_MIN/-1 para operaci\u00f3n de 64 bits - INT_MIN/-1 para operaci\u00f3n de 32 bits - LLONG_MIN%-1 para operaci\u00f3n de 64 bits - INT_MIN%-1 para operaci\u00f3n de 32 bits donde -1 puede ser inmediato o en un registro. En arm64, no hay excepciones: - LLONG_MIN/-1 = LLONG_MIN - INT_MIN/-1 = INT_MIN - LLONG_MIN%-1 = 0 - INT_MIN%-1 = 0 donde -1 puede ser inmediato o en un registro. Se necesita aplicar un parche a Insn para manejar los casos anteriores y los c\u00f3digos parcheados produjeron resultados alineados con el resultado de arm64 anterior. Los siguientes son pseudoc\u00f3digos para manejar excepciones sdiv/smod incluyendo tanto el divisor -1 como el divisor 0 y el divisor se almacena en un registro. sdiv: tmp = rX tmp += 1 /* [-1, 0] -\u0026gt; [0, 1] if tmp \u0026gt;(unsigned) 1 goto L2 if tmp == 0 goto L1 rY = 0 L1: rY = -rY; goto L3 L2: rY /= rX L3: smod: tmp = rX tmp += 1 /* [-1, 0] -\u0026gt; [0, 1] if tmp \u0026gt;(unsigned) 1 goto L1 if tmp == 1 (is64 ? goto L2 : goto L3) rY = 0; goto L2 L1: rY %= rX L2: goto L4 // solo cuando !is64 L3: wY = wY // solo cuando !is64 L4: [1] https://lore.kernel.org/bpf/tPJLTEh7S_DxFEqAI2Ji5MBSoZVg7_G-Py2iaZpAaWtM961fFTWtsnlzwvTbzBzaUzwQAoNATXKUlt0LZOFgnDcIyKCswAnAGdUF3LBrhGQ=@protonmail.com/"
    }
  ],
  "id": "CVE-2024-49888",
  "lastModified": "2024-11-13T14:54:25.787",
  "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": "2024-10-21T18:15:11.443",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/4902a6a0dc593c82055fc8c9ada371bafe26c9cc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/7dd34d7b7dcf9309fc6224caf4dd5b35bedddcb7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/d22e45a369afc7c28f11acfa5b5e8e478227ca5d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-190"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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