fkie_cve-2024-46704
Vulnerability from fkie_nvd
Published
2024-09-13 07:15
Modified
2024-09-19 13:32
Severity ?
4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix spruious data race in __flush_work() When flushing a work item for cancellation, __flush_work() knows that it exclusively owns the work item through its PENDING bit. 134874e2eee9 ("workqueue: Allow cancel_work_sync() and disable_work() from atomic contexts on BH work items") added a read of @work->data to determine whether to use busy wait for BH work items that are being canceled. While the read is safe when @from_cancel, @work->data was read before testing @from_cancel to simplify code structure: data = *work_data_bits(work); if (from_cancel && !WARN_ON_ONCE(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_BH)) { While the read data was never used if !@from_cancel, this could trigger KCSAN data race detection spuriously: ================================================================== BUG: KCSAN: data-race in __flush_work / __flush_work write to 0xffff8881223aa3e8 of 8 bytes by task 3998 on cpu 0: instrument_write include/linux/instrumented.h:41 [inline] ___set_bit include/asm-generic/bitops/instrumented-non-atomic.h:28 [inline] insert_wq_barrier kernel/workqueue.c:3790 [inline] start_flush_work kernel/workqueue.c:4142 [inline] __flush_work+0x30b/0x570 kernel/workqueue.c:4178 flush_work kernel/workqueue.c:4229 [inline] ... read to 0xffff8881223aa3e8 of 8 bytes by task 50 on cpu 1: __flush_work+0x42a/0x570 kernel/workqueue.c:4188 flush_work kernel/workqueue.c:4229 [inline] flush_delayed_work+0x66/0x70 kernel/workqueue.c:4251 ... value changed: 0x0000000000400000 -> 0xffff88810006c00d Reorganize the code so that @from_cancel is tested before @work->data is accessed. The only problem is triggering KCSAN detection spuriously. This shouldn't need READ_ONCE() or other access qualifiers. No functional changes.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8bc35475ef1a23b0e224f3242eb11c76cab0ea88Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/91d09642127a32fde231face2ff489af70eef316Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel 6.11
linux linux_kernel 6.11
linux linux_kernel 6.11
linux linux_kernel 6.11


To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "E55C1263-DF43-41EF-8DA8-2BA68DF4FFFD",
              "versionEndExcluding": "6.10.7",
              "versionStartIncluding": "6.10",
              "vulnerable": true
            },
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              "criteria": "cpe:2.3:o:linux:linux_kernel:6.11:rc1:*:*:*:*:*:*",
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          "operator": "OR"
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix spruious data race in __flush_work()\n\nWhen flushing a work item for cancellation, __flush_work() knows that it\nexclusively owns the work item through its PENDING bit. 134874e2eee9\n(\"workqueue: Allow cancel_work_sync() and disable_work() from atomic\ncontexts on BH work items\") added a read of @work-\u003edata to determine whether\nto use busy wait for BH work items that are being canceled. While the read\nis safe when @from_cancel, @work-\u003edata was read before testing @from_cancel\nto simplify code structure:\n\n\tdata = *work_data_bits(work);\n\tif (from_cancel \u0026\u0026\n\t    !WARN_ON_ONCE(data \u0026 WORK_STRUCT_PWQ) \u0026\u0026 (data \u0026 WORK_OFFQ_BH)) {\n\nWhile the read data was never used if !@from_cancel, this could trigger\nKCSAN data race detection spuriously:\n\n  ==================================================================\n  BUG: KCSAN: data-race in __flush_work / __flush_work\n\n  write to 0xffff8881223aa3e8 of 8 bytes by task 3998 on cpu 0:\n   instrument_write include/linux/instrumented.h:41 [inline]\n   ___set_bit include/asm-generic/bitops/instrumented-non-atomic.h:28 [inline]\n   insert_wq_barrier kernel/workqueue.c:3790 [inline]\n   start_flush_work kernel/workqueue.c:4142 [inline]\n   __flush_work+0x30b/0x570 kernel/workqueue.c:4178\n   flush_work kernel/workqueue.c:4229 [inline]\n   ...\n\n  read to 0xffff8881223aa3e8 of 8 bytes by task 50 on cpu 1:\n   __flush_work+0x42a/0x570 kernel/workqueue.c:4188\n   flush_work kernel/workqueue.c:4229 [inline]\n   flush_delayed_work+0x66/0x70 kernel/workqueue.c:4251\n   ...\n\n  value changed: 0x0000000000400000 -\u003e 0xffff88810006c00d\n\nReorganize the code so that @from_cancel is tested before @work-\u003edata is\naccessed. The only problem is triggering KCSAN detection spuriously. This\nshouldn\u0027t need READ_ONCE() or other access qualifiers.\n\nNo functional changes."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: workqueue: Fix spruious data race in __flush_work() Al vaciar un elemento de trabajo para su cancelaci\u00f3n, __flush_work() sabe que posee exclusivamente el elemento de trabajo a trav\u00e9s de su bit PENDING. 134874e2eee9 (\"workqueue: Allow cancel_work_sync() and disable_work() from atomic contexts on BH work items\") agreg\u00f3 una lectura de @work-\u0026gt;data para determinar si se debe usar la espera activa para los elementos de trabajo de BH que se est\u00e1n cancelando. Si bien la lectura es segura cuando @from_cancel, @work-\u0026gt;data se ley\u00f3 antes de probar @from_cancel para simplificar la estructura del c\u00f3digo: data = *work_data_bits(work); if (from_cancel \u0026amp;\u0026amp; !WARN_ON_ONCE(data \u0026amp; WORK_STRUCT_PWQ) \u0026amp;\u0026amp; (data \u0026amp; WORK_OFFQ_BH)) { Si bien los datos le\u00eddos nunca se usaron si !@from_cancel, esto podr\u00eda activar la detecci\u00f3n de ejecuci\u00f3n de datos de KCSAN de manera espuria: ====================================================================== ERROR: KCSAN: carrera de datos en __flush_work / __flush_work escribe en 0xffff8881223aa3e8 de 8 bytes por la tarea 3998 en la CPU 0: instrument_write include/linux/instrumented.h:41 [en l\u00ednea] ___set_bit include/asm-generic/bitops/instrumented-non-atomic.h:28 [en l\u00ednea] insert_wq_barrier kernel/workqueue.c:3790 [en l\u00ednea] start_flush_work kernel/workqueue.c:4142 [en l\u00ednea] __flush_work+0x30b/0x570 kernel/workqueue.c:4178 flush_work kernel/workqueue.c:4229 [en l\u00ednea] ... le\u00eddo hasta 0xffff8881223aa3e8 de 8 bytes por la tarea 50 en la CPU 1: __flush_work+0x42a/0x570 kernel/workqueue.c:4188 flush_work kernel/workqueue.c:4229 [en l\u00ednea] flush_delayed_work+0x66/0x70 kernel/workqueue.c:4251 ... valor cambiado: 0x0000000000400000 -\u0026gt; 0xffff88810006c00d Reorganice el c\u00f3digo para que @from_cancel se pruebe antes de acceder a @work-\u0026gt;data. El \u00fanico problema es que se activa la detecci\u00f3n de KCSAN de manera espuria. Esto no deber\u00eda necesitar READ_ONCE() ni otros calificadores de acceso. No hay cambios funcionales."
    }
  ],
  "id": "CVE-2024-46704",
  "lastModified": "2024-09-19T13:32:39.257",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2024-09-13T07:15:05.397",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/8bc35475ef1a23b0e224f3242eb11c76cab0ea88"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      "url": "https://git.kernel.org/stable/c/91d09642127a32fde231face2ff489af70eef316"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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