gsd-2024-26757
Vulnerability from gsd
Modified
2024-02-20 06:02
Details
In the Linux kernel, the following vulnerability has been resolved: md: Don't ignore read-only array in md_check_recovery() Usually if the array is not read-write, md_check_recovery() won't register new sync_thread in the first place. And if the array is read-write and sync_thread is registered, md_set_readonly() will unregister sync_thread before setting the array read-only. md/raid follow this behavior hence there is no problem. After commit f52f5c71f3d4 ("md: fix stopping sync thread"), following hang can be triggered by test shell/integrity-caching.sh: 1) array is read-only. dm-raid update super block: rs_update_sbs ro = mddev->ro mddev->ro = 0 -> set array read-write md_update_sb 2) register new sync thread concurrently. 3) dm-raid set array back to read-only: rs_update_sbs mddev->ro = ro 4) stop the array: 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) sync thread done: md_do_sync set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); 6) daemon thread can't unregister sync thread: md_check_recovery if (!md_is_rdwr(mddev) && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) return; -> -> MD_RECOVERY_RUNNING can't be cleared, hence step 4 hang; The root cause is that dm-raid manipulate 'mddev->ro' by itself, however, dm-raid really should stop sync thread before setting the array read-only. Unfortunately, I need to read more code before I can refacter the handler of 'mddev->ro' in dm-raid, hence let's fix the problem the easy way for now to prevent dm-raid regression.
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{
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2024-26757"
      ],
      "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: Don\u0027t ignore read-only array in md_check_recovery()\n\nUsually if the array is not read-write, md_check_recovery() won\u0027t\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-\u003ero\n mddev-\u003ero = 0\n  -\u003e 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-\u003ero = ro\n\n4) stop the array:\nraid_dtr\n md_stop\n  stop_sync_thread\n    set_bit(MD_RECOVERY_INTR, \u0026mddev-\u003erecovery);\n    md_wakeup_thread_directly(mddev-\u003esync_thread);\n    wait_event(..., !test_bit(MD_RECOVERY_RUNNING, \u0026mddev-\u003erecovery))\n\n5) sync thread done:\n md_do_sync\n set_bit(MD_RECOVERY_DONE, \u0026mddev-\u003erecovery);\n md_wakeup_thread(mddev-\u003ethread);\n\n6) daemon thread can\u0027t unregister sync thread:\n md_check_recovery\n  if (!md_is_rdwr(mddev) \u0026\u0026\n      !test_bit(MD_RECOVERY_NEEDED, \u0026mddev-\u003erecovery))\n   return;\n  -\u003e -\u003e MD_RECOVERY_RUNNING can\u0027t be cleared, hence step 4 hang;\n\nThe root cause is that dm-raid manipulate \u0027mddev-\u003ero\u0027 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 \u0027mddev-\u003ero\u0027 in dm-raid, hence let\u0027s fix\nthe problem the easy way for now to prevent dm-raid regression.",
      "id": "GSD-2024-26757",
      "modified": "2024-02-20T06:02:29.233475Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "cve@kernel.org",
        "ID": "CVE-2024-26757",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "Linux",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "\u003c",
                          "version_name": "ecbfb9f118bc",
                          "version_value": "2ea169c5a0b1"
                        },
                        {
                          "version_value": "not down converted",
                          "x_cve_json_5_version_data": {
                            "defaultStatus": "affected",
                            "versions": [
                              {
                                "status": "affected",
                                "version": "4.8"
                              },
                              {
                                "lessThan": "4.8",
                                "status": "unaffected",
                                "version": "0",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "6.7.*",
                                "status": "unaffected",
                                "version": "6.7.7",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "*",
                                "status": "unaffected",
                                "version": "6.8",
                                "versionType": "original_commit_for_fix"
                              }
                            ]
                          }
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "Linux"
            }
          ]
        }
      },
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: Don\u0027t ignore read-only array in md_check_recovery()\n\nUsually if the array is not read-write, md_check_recovery() won\u0027t\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-\u003ero\n mddev-\u003ero = 0\n  -\u003e 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-\u003ero = ro\n\n4) stop the array:\nraid_dtr\n md_stop\n  stop_sync_thread\n    set_bit(MD_RECOVERY_INTR, \u0026mddev-\u003erecovery);\n    md_wakeup_thread_directly(mddev-\u003esync_thread);\n    wait_event(..., !test_bit(MD_RECOVERY_RUNNING, \u0026mddev-\u003erecovery))\n\n5) sync thread done:\n md_do_sync\n set_bit(MD_RECOVERY_DONE, \u0026mddev-\u003erecovery);\n md_wakeup_thread(mddev-\u003ethread);\n\n6) daemon thread can\u0027t unregister sync thread:\n md_check_recovery\n  if (!md_is_rdwr(mddev) \u0026\u0026\n      !test_bit(MD_RECOVERY_NEEDED, \u0026mddev-\u003erecovery))\n   return;\n  -\u003e -\u003e MD_RECOVERY_RUNNING can\u0027t be cleared, hence step 4 hang;\n\nThe root cause is that dm-raid manipulate \u0027mddev-\u003ero\u0027 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 \u0027mddev-\u003ero\u0027 in dm-raid, hence let\u0027s fix\nthe problem the easy way for now to prevent dm-raid regression."
          }
        ]
      },
      "generator": {
        "engine": "bippy-5f0117140d9a"
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "n/a"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3"
          },
          {
            "name": "https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b"
          }
        ]
      }
    },
    "nvd.nist.gov": {
      "cve": {
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: Don\u0027t ignore read-only array in md_check_recovery()\n\nUsually if the array is not read-write, md_check_recovery() won\u0027t\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-\u003ero\n mddev-\u003ero = 0\n  -\u003e 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-\u003ero = ro\n\n4) stop the array:\nraid_dtr\n md_stop\n  stop_sync_thread\n    set_bit(MD_RECOVERY_INTR, \u0026mddev-\u003erecovery);\n    md_wakeup_thread_directly(mddev-\u003esync_thread);\n    wait_event(..., !test_bit(MD_RECOVERY_RUNNING, \u0026mddev-\u003erecovery))\n\n5) sync thread done:\n md_do_sync\n set_bit(MD_RECOVERY_DONE, \u0026mddev-\u003erecovery);\n md_wakeup_thread(mddev-\u003ethread);\n\n6) daemon thread can\u0027t unregister sync thread:\n md_check_recovery\n  if (!md_is_rdwr(mddev) \u0026\u0026\n      !test_bit(MD_RECOVERY_NEEDED, \u0026mddev-\u003erecovery))\n   return;\n  -\u003e -\u003e MD_RECOVERY_RUNNING can\u0027t be cleared, hence step 4 hang;\n\nThe root cause is that dm-raid manipulate \u0027mddev-\u003ero\u0027 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 \u0027mddev-\u003ero\u0027 in dm-raid, hence let\u0027s fix\nthe problem the easy way for now to prevent dm-raid regression."
          }
        ],
        "id": "CVE-2024-26757",
        "lastModified": "2024-04-03T17:24:18.150",
        "metrics": {},
        "published": "2024-04-03T17:15:52.207",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    }
  }
}


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