{
  "id": "CVE-2024-26757",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2024-04-03T17:15:52.207",
  "lastModified": "2024-11-21T09:03:00.147",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: Don't ignore read-only array in md_check_recovery()\n\nUsually if the array is not read-write, md_check_recovery() won't\nregister new sync_thread in the first place. And if the array is\nread-write and sync_thread is registered, md_set_readonly() will\nunregister sync_thread before setting the array read-only. md/raid\nfollow this behavior hence there is no problem.\n\nAfter commit f52f5c71f3d4 (\"md: fix stopping sync thread\"), following\nhang can be triggered by test shell/integrity-caching.sh:\n\n1) array is read-only. dm-raid update super block:\nrs_update_sbs\n ro = mddev->ro\n mddev->ro = 0\n  -> set array read-write\n md_update_sb\n\n2) register new sync thread concurrently.\n\n3) dm-raid set array back to read-only:\nrs_update_sbs\n mddev->ro = ro\n\n4) stop the array:\nraid_dtr\n md_stop\n  stop_sync_thread\n    set_bit(MD_RECOVERY_INTR, &mddev->recovery);\n    md_wakeup_thread_directly(mddev->sync_thread);\n    wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))\n\n5) sync thread done:\n md_do_sync\n set_bit(MD_RECOVERY_DONE, &mddev->recovery);\n md_wakeup_thread(mddev->thread);\n\n6) daemon thread can't unregister sync thread:\n md_check_recovery\n  if (!md_is_rdwr(mddev) &&\n      !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))\n   return;\n  -> -> MD_RECOVERY_RUNNING can't be cleared, hence step 4 hang;\n\nThe root cause is that dm-raid manipulate 'mddev->ro' by itself,\nhowever, dm-raid really should stop sync thread before setting the\narray read-only. Unfortunately, I need to read more code before I\ncan refacter the handler of 'mddev->ro' in dm-raid, hence let's fix\nthe problem the easy way for now to prevent dm-raid regression."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: md: No ignorar la matriz de solo lectura en md_check_recovery() Generalmente, si la matriz no es de lectura y escritura, md_check_recovery() no registrar\u00e1 un nuevo sync_thread en primer lugar. Y si la matriz es de lectura y escritura y sync_thread est\u00e1 registrado, md_set_readonly() cancelar\u00e1 el registro de sync_thread antes de configurar la matriz como de solo lectura. md/raid sigue este comportamiento, por lo que no hay problema. Despu\u00e9s de commit f52f5c71f3d4 (\"md: arreglar la detenci\u00f3n del hilo de sincronizaci\u00f3n\"), el siguiente bloqueo puede activarse mediante test shell/integrity-caching.sh: 1) la matriz es de solo lectura. Superbloque de actualizaci\u00f3n dm-raid: rs_update_sbs ro = mddev->ro mddev->ro = 0 -> establecer matriz de lectura y escritura md_update_sb 2) registrar un nuevo hilo de sincronizaci\u00f3n simult\u00e1neamente. 3) dm-raid vuelve a configurar la matriz en solo lectura: rs_update_sbs mddev->ro = ro 4) detiene la matriz: raid_dtr md_stop stop_sync_thread set_bit(MD_RECOVERY_INTR, &mddev->recovery); md_wakeup_thread_directly(mddev->sync_thread); wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 5) hilo de sincronizaci\u00f3n realizado: md_do_sync set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); 6) el hilo del demonio no puede cancelar el registro del hilo de sincronizaci\u00f3n: md_check_recovery if (!md_is_rdwr(mddev) && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) return; -> -> MD_RECOVERY_RUNNING no se puede borrar, por lo tanto el paso 4 se bloquea; La causa principal es que dm-raid manipula 'mddev->ro' por s\u00ed solo; sin embargo, dm-raid realmente deber\u00eda detener el hilo de sincronizaci\u00f3n antes de configurar la matriz como de solo lectura. Desafortunadamente, necesito leer m\u00e1s c\u00f3digo antes de poder refactorizar el controlador de 'mddev->ro' en dm-raid, por lo tanto, solucionemos el problema de la manera m\u00e1s f\u00e1cil por ahora para evitar la regresi\u00f3n de dm-raid."
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-404"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}