FKIE_CVE-2024-42240

Vulnerability from fkie_nvd - Published: 2024-08-07 16:15 - Updated: 2025-11-03 22:17
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: x86/bhi: Avoid warning in #DB handler due to BHI mitigation When BHI mitigation is enabled, if SYSENTER is invoked with the TF flag set then entry_SYSENTER_compat() uses CLEAR_BRANCH_HISTORY and calls the clear_bhb_loop() before the TF flag is cleared. This causes the #DB handler (exc_debug_kernel()) to issue a warning because single-step is used outside the entry_SYSENTER_compat() function. To address this issue, entry_SYSENTER_compat() should use CLEAR_BRANCH_HISTORY after making sure the TF flag is cleared. The problem can be reproduced with the following sequence: $ cat sysenter_step.c int main() { asm("pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter"); } $ gcc -o sysenter_step sysenter_step.c $ ./sysenter_step Segmentation fault (core dumped) The program is expected to crash, and the #DB handler will issue a warning. Kernel log: WARNING: CPU: 27 PID: 7000 at arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160 ... RIP: 0010:exc_debug_kernel+0xd2/0x160 ... Call Trace: <#DB> ? show_regs+0x68/0x80 ? __warn+0x8c/0x140 ? exc_debug_kernel+0xd2/0x160 ? report_bug+0x175/0x1a0 ? handle_bug+0x44/0x90 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? exc_debug_kernel+0xd2/0x160 exc_debug+0x43/0x50 asm_exc_debug+0x1e/0x40 RIP: 0010:clear_bhb_loop+0x0/0xb0 ... </#DB> <TASK> ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d </TASK> [ bp: Massage commit message. ]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cfPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84Patch
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CAAB30CE-506C-42CC-B146-52655F61012E",
              "versionEndExcluding": "6.1.100",
              "versionStartIncluding": "5.15.163",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "96AC42B8-D66D-4AC5-B466-E9BA7910FA29",
              "versionEndExcluding": "6.6.41",
              "versionStartIncluding": "6.2",
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            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "AB2E8DEC-CFD5-4C2B-981D-E7E45A36C352",
              "versionEndExcluding": "6.9.10",
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            }
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          "negate": false,
          "operator": "OR"
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/bhi: Avoid warning in #DB handler due to BHI mitigation\n\nWhen BHI mitigation is enabled, if SYSENTER is invoked with the TF flag set\nthen entry_SYSENTER_compat() uses CLEAR_BRANCH_HISTORY and calls the\nclear_bhb_loop() before the TF flag is cleared. This causes the #DB handler\n(exc_debug_kernel()) to issue a warning because single-step is used outside the\nentry_SYSENTER_compat() function.\n\nTo address this issue, entry_SYSENTER_compat() should use CLEAR_BRANCH_HISTORY\nafter making sure the TF flag is cleared.\n\nThe problem can be reproduced with the following sequence:\n\n  $ cat sysenter_step.c\n  int main()\n  { asm(\"pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter\"); }\n\n  $ gcc -o sysenter_step sysenter_step.c\n\n  $ ./sysenter_step\n  Segmentation fault (core dumped)\n\nThe program is expected to crash, and the #DB handler will issue a warning.\n\nKernel log:\n\n  WARNING: CPU: 27 PID: 7000 at arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160\n  ...\n  RIP: 0010:exc_debug_kernel+0xd2/0x160\n  ...\n  Call Trace:\n  \u003c#DB\u003e\n   ? show_regs+0x68/0x80\n   ? __warn+0x8c/0x140\n   ? exc_debug_kernel+0xd2/0x160\n   ? report_bug+0x175/0x1a0\n   ? handle_bug+0x44/0x90\n   ? exc_invalid_op+0x1c/0x70\n   ? asm_exc_invalid_op+0x1f/0x30\n   ? exc_debug_kernel+0xd2/0x160\n   exc_debug+0x43/0x50\n   asm_exc_debug+0x1e/0x40\n  RIP: 0010:clear_bhb_loop+0x0/0xb0\n  ...\n  \u003c/#DB\u003e\n  \u003cTASK\u003e\n   ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d\n  \u003c/TASK\u003e\n\n  [ bp: Massage commit message. ]"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: x86/bhi: evitar advertencia en el controlador #DB debido a la mitigaci\u00f3n de BHI Cuando la mitigaci\u00f3n de BHI est\u00e1 habilitada, si se invoca SYSENTER con el indicador TF configurado, entonces Entry_SYSENTER_compat() usa CLEAR_BRANCH_HISTORY y llama al clear_bhb_loop() antes de que se borre la bandera TF. Esto hace que el controlador #DB (exc_debug_kernel()) emita una advertencia porque se utiliza un solo paso fuera de la funci\u00f3n Entry_SYSENTER_compat(). Para solucionar este problema, Entry_SYSENTER_compat() debe usar CLEAR_BRANCH_HISTORY despu\u00e9s de asegurarse de que el indicador TF est\u00e9 borrado. El problema se puede reproducir con la siguiente secuencia: $ cat sysenter_step.c int main() { asm(\"pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter\"); } $ gcc -o sysenter_step sysenter_step.c $ ./sysenter_step Fallo de segmentaci\u00f3n (n\u00facleo volcado) Se espera que el programa falle y el controlador #DB emitir\u00e1 una advertencia. Registro del kernel: ADVERTENCIA: CPU: 27 PID: 7000 en arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160... RIP: 0010:exc_debug_kernel+0xd2/0x160... Seguimiento de llamadas: \u0026lt;#DB\u0026gt; ? show_regs+0x68/0x80? __advertir+0x8c/0x140 ? exc_debug_kernel+0xd2/0x160? report_bug+0x175/0x1a0? handle_bug+0x44/0x90? exc_invalid_op+0x1c/0x70? asm_exc_invalid_op+0x1f/0x30? exc_debug_kernel+0xd2/0x160 exc_debug+0x43/0x50 asm_exc_debug+0x1e/0x40 RIP: 0010:clear_bhb_loop+0x0/0xb0 ...   ? Entry_SYSENTER_compat_after_hwframe+0x6e/0x8d  [bp: mensaje de commit de masaje. ]"
    }
  ],
  "id": "CVE-2024-42240",
  "lastModified": "2025-11-03T22:17:49.327",
  "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": "2024-08-07T16:15:46.810",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
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      "url": "https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364"
    },
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
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      "url": "https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-835"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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