nvd-json-data-feeds/CVE-2024/CVE-2024-422xx/CVE-2024-42240.json

{
  "id": "CVE-2024-42240",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2024-08-07T16:15:46.810",
  "lastModified": "2024-08-08T14:53:59.897",
  "vulnStatus": "Analyzed",
  "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  <#DB>\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  </#DB>\n  <TASK>\n   ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d\n  </TASK>\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: &lt;#DB&gt; ? 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. ]"
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "nvd@nist.gov",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "nvd@nist.gov",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-835"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
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          "operator": "OR",
          "negate": false,
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  "references": [
    {
      "url": "https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513",
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