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CVE-2022-49079

Estado: AnalizadaMedia (5.5)—

In the Linux kernel, the following vulnerability has been resolved:

btrfs: zoned: traverse devices under chunk_mutex in btrfs_can_activate_zone

btrfs_can_activate_zone() can be called with the device_list_mutex already held, which will lead to a deadlock:

Instead of using the RCU on fs_devices->device_list we can use fs_devices->alloc_list, protected by the chunk_mutex to traverse the list of active devices.

We are in the chunk allocation thread. The newer chunk allocation happens from the devices in the fs_device->alloc_list protected by the chunk_mutex.

Also, a device that reappears after the mount won't join the alloc_list yet and, it will be in the dev_list, which we don't want to consider in the context of the chunk alloc.

Detalles técnicos trazas, registros y código del informe original
insert_dev_extents() // Takes device_list_mutex
`-> insert_dev_extent()
 `-> btrfs_insert_empty_item()
  `-> btrfs_insert_empty_items()
   `-> btrfs_search_slot()
    `-> btrfs_cow_block()
     `-> __btrfs_cow_block()
      `-> btrfs_alloc_tree_block()
       `-> btrfs_reserve_extent()
        `-> find_free_extent()
         `-> find_free_extent_update_loop()
          `-> can_allocate_chunk()
           `-> btrfs_can_activate_zone() // Takes device_list_mutex again

  btrfs_create_chunk()
    lockdep_assert_held(&info->chunk_mutex);
    gather_device_info
      list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list)

  [15.166572] WARNING: possible recursive locking detected
  [15.167117] 5.17.0-rc6-dennis #79 Not tainted
  [15.167487] --------------------------------------------
  [15.167733] kworker/u8:3/146 is trying to acquire lock:
  [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: find_free_extent+0x15a/0x14f0 [btrfs]
  [15.167733]
  [15.167733] but task is already holding lock:
  [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs]
  [15.167733]
  [15.167733] other info that might help us debug this:
  [15.167733]  Possible unsafe locking scenario:
  [15.167733]
  [15.171834]        CPU0
  [15.171834]        ----
  [15.171834]   lock(&fs_devs->device_list_mutex);
  [15.171834]   lock(&fs_devs->device_list_mutex);
  [15.171834]
  [15.171834]  *** DEADLOCK ***
  [15.171834]
  [15.171834]  May be due to missing lock nesting notation
  [15.171834]
  [15.171834] 5 locks held by kworker/u8:3/146:
  [15.171834]  #0: ffff888100050938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0
  [15.171834]  #1: ffffc9000067be80 ((work_completion)(&fs_info->async_data_reclaim_work)){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0
  [15.176244]  #2: ffff88810521e620 (sb_internal){.+.+}-{0:0}, at: flush_space+0x335/0x600 [btrfs]
  [15.176244]  #3: ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs]
  [15.176244]  #4: ffff8881152e4b78 (btrfs-dev-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x130 [btrfs]
  [15.179641]
  [15.179641] stack backtrace:
  [15.179641] CPU: 1 PID: 146 Comm: kworker/u8:3 Not tainted 5.17.0-rc6-dennis #79
  [15.179641] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014
  [15.179641] Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]
  [15.179641] Call Trace:
  [15.179641]  <TASK>
  [15.179641]  dump_stack_lvl+0x45/0x59
  [15.179641]  __lock_acquire.cold+0x217/0x2b2
  [15.179641]  lock_acquire+0xbf/0x2b0
  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
  [15.183838]  __mutex_lock+0x8e/0x970
  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
  [15.183838]  ? lock_is_held_type+0xd7/0x130
  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
  [15.183838]  find_free_extent+0x15a/0x14f0 [btrfs]
  [15.183838]  ? _raw_spin_unlock+0x24/0x40
  [15.183838]  ? btrfs_get_alloc_profile+0x106/0x230 [btrfs]
  [15.187601]  btrfs_reserve_extent+0x131/0x260 [btrfs]
  [15.
---truncated---

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2022-49079",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "a85f05e59bc15a83ad910dbcb71df5ad8fa77295",
              "lessThan": "09e65ae515af2b24d6dc23af21719a3b41de83e5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a85f05e59bc15a83ad910dbcb71df5ad8fa77295",
              "lessThan": "142f822bd945a7be442a2916ec6167cc102c4183",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a85f05e59bc15a83ad910dbcb71df5ad8fa77295",
              "lessThan": "0b9e66762aa0cda2a9c2d5542d64e04dac528fa6",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/btrfs/zoned.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.16.20",
              "versionType": "semver",
              "lessThanOrEqual": "5.16.*"
            },
            {
              "status": "unaffected",
              "version": "5.17.3",
              "versionType": "semver",
              "lessThanOrEqual": "5.17.*"
            },
            {
              "status": "unaffected",
              "version": "5.18",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/btrfs/zoned.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-02-26T07:00:45.250",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/09e65ae515af2b24d6dc23af21719a3b41de83e5",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0b9e66762aa0cda2a9c2d5542d64e04dac528fa6",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/142f822bd945a7be442a2916ec6167cc102c4183",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-667"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zoned: traverse devices under chunk_mutex in btrfs_can_activate_zone\n\nbtrfs_can_activate_zone() can be called with the device_list_mutex already\nheld, which will lead to a deadlock:\n\ninsert_dev_extents() // Takes device_list_mutex\n`-> insert_dev_extent()\n `-> btrfs_insert_empty_item()\n  `-> btrfs_insert_empty_items()\n   `-> btrfs_search_slot()\n    `-> btrfs_cow_block()\n     `-> __btrfs_cow_block()\n      `-> btrfs_alloc_tree_block()\n       `-> btrfs_reserve_extent()\n        `-> find_free_extent()\n         `-> find_free_extent_update_loop()\n          `-> can_allocate_chunk()\n           `-> btrfs_can_activate_zone() // Takes device_list_mutex again\n\nInstead of using the RCU on fs_devices->device_list we\ncan use fs_devices->alloc_list, protected by the chunk_mutex to traverse\nthe list of active devices.\n\nWe are in the chunk allocation thread. The newer chunk allocation\nhappens from the devices in the fs_device->alloc_list protected by the\nchunk_mutex.\n\n  btrfs_create_chunk()\n    lockdep_assert_held(&info->chunk_mutex);\n    gather_device_info\n      list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list)\n\nAlso, a device that reappears after the mount won't join the alloc_list\nyet and, it will be in the dev_list, which we don't want to consider in\nthe context of the chunk alloc.\n\n  [15.166572] WARNING: possible recursive locking detected\n  [15.167117] 5.17.0-rc6-dennis #79 Not tainted\n  [15.167487] --------------------------------------------\n  [15.167733] kworker/u8:3/146 is trying to acquire lock:\n  [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: find_free_extent+0x15a/0x14f0 [btrfs]\n  [15.167733]\n  [15.167733] but task is already holding lock:\n  [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs]\n  [15.167733]\n  [15.167733] other info that might help us debug this:\n  [15.167733]  Possible unsafe locking scenario:\n  [15.167733]\n  [15.171834]        CPU0\n  [15.171834]        ----\n  [15.171834]   lock(&fs_devs->device_list_mutex);\n  [15.171834]   lock(&fs_devs->device_list_mutex);\n  [15.171834]\n  [15.171834]  *** DEADLOCK ***\n  [15.171834]\n  [15.171834]  May be due to missing lock nesting notation\n  [15.171834]\n  [15.171834] 5 locks held by kworker/u8:3/146:\n  [15.171834]  #0: ffff888100050938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0\n  [15.171834]  #1: ffffc9000067be80 ((work_completion)(&fs_info->async_data_reclaim_work)){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0\n  [15.176244]  #2: ffff88810521e620 (sb_internal){.+.+}-{0:0}, at: flush_space+0x335/0x600 [btrfs]\n  [15.176244]  #3: ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs]\n  [15.176244]  #4: ffff8881152e4b78 (btrfs-dev-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x130 [btrfs]\n  [15.179641]\n  [15.179641] stack backtrace:\n  [15.179641] CPU: 1 PID: 146 Comm: kworker/u8:3 Not tainted 5.17.0-rc6-dennis #79\n  [15.179641] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014\n  [15.179641] Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]\n  [15.179641] Call Trace:\n  [15.179641]  <TASK>\n  [15.179641]  dump_stack_lvl+0x45/0x59\n  [15.179641]  __lock_acquire.cold+0x217/0x2b2\n  [15.179641]  lock_acquire+0xbf/0x2b0\n  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]\n  [15.183838]  __mutex_lock+0x8e/0x970\n  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]\n  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]\n  [15.183838]  ? lock_is_held_type+0xd7/0x130\n  [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]\n  [15.183838]  find_free_extent+0x15a/0x14f0 [btrfs]\n  [15.183838]  ? _raw_spin_unlock+0x24/0x40\n  [15.183838]  ? btrfs_get_alloc_profile+0x106/0x230 [btrfs]\n  [15.187601]  btrfs_reserve_extent+0x131/0x260 [btrfs]\n  [15.\n---truncated---"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: btrfs: zoned: atravesar dispositivos bajo chunk_mutex en btrfs_can_activate_zone btrfs_can_activate_zone() se puede llamar con el device_list_mutex ya retenido, lo que provocará un bloqueo: insert_dev_extents() // Toma device_list_mutex `-&gt; insert_dev_extent() `-&gt; btrfs_insert_empty_item() `-&gt; btrfs_insert_empty_items() `-&gt; btrfs_search_slot() `-&gt; btrfs_cow_block() `-&gt; __btrfs_cow_block() `-&gt; btrfs_alloc_tree_block() `-&gt; btrfs_reserve_extent() `-&gt; find_free_extent() `-&gt; find_free_extent_update_loop() `-&gt; can_allocate_chunk() `-&gt; btrfs_can_activate_zone() // Toma device_list_mutex nuevamente En lugar de usar la RCU en fs_devices-&gt;device_list podemos usar fs_devices-&gt;alloc_list, protegido por chunk_mutex para recorrer la lista de dispositivos activos. Estamos en el hilo de asignación de fragmentos. La asignación de fragmentos más nueva ocurre desde los dispositivos en fs_device-&gt;alloc_list protegidos por chunk_mutex. btrfs_create_chunk() lockdep_assert_held(&amp;info-&gt;chunk_mutex); gather_device_info list_for_each_entry(device, &amp;fs_devices-&gt;alloc_list, dev_alloc_list) Además, un dispositivo que reaparece después del montaje no se unirá a alloc_list todavía y estará en dev_list, que no queremos considerar en el contexto de la asignación de fragmentos. [15.166572] ADVERTENCIA: se detectó un posible bloqueo recursivo [15.167117] 5.17.0-rc6-dennis #79 No contaminado [15.167487] -------------------------------------------- [15.167733] kworker/u8:3/146 está intentando adquirir el bloqueo: [15.167733] ffff888102962ee0 (&amp;fs_devs-&gt;device_list_mutex){+.+.}-{3:3}, en: find_free_extent+0x15a/0x14f0 [btrfs] [15.167733] [15.167733] pero la tarea ya tiene el bloqueo: [15.167733] ffff888102962ee0 (&amp;fs_devs-&gt;device_list_mutex){+.+.}-{3:3}, en: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs] [15.167733] [15.167733] otra información que podría ayudarnos a depurar esto: [15.167733] Posible escenario de bloqueo inseguro: [15.167733] [15.171834] CPU0 [15.171834] ---- [15.171834] lock(&amp;fs_devs-&gt;device_list_mutex); [15.171834] lock(&amp;fs_devs-&gt;device_list_mutex); [15.171834] [15.171834] *** BLOQUEO INTERMEDIO *** [15.171834] [15.171834] Puede deberse a la falta de notación de anidamiento de bloqueos [15.171834] [15.171834] 5 bloqueos retenidos por kworker/u8:3/146: [15.171834] #0: ffff888100050938 ((wq_completion)events_unbound){+.+.}-{0:0}, en: process_one_work+0x1c3/0x5a0 [15.171834] #1: ffffc9000067be80 ((work_completion)(&amp;fs_info-&gt;async_data_reclaim_work)){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0 [15.176244] #2: ffff88810521e620 (sb_internal){.+.+}-{0:0}, at: flush_space+0x335/0x600 [btrfs] [15.176244] #3: ffff888102962ee0 (&amp;fs_devs-&gt;device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs] [15.176244] #4: ffff8881152e4b78 (btrfs-dev-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x130 [btrfs] [15.179641] [15.179641] stack backtrace: [15.179641] CPU: 1 PID: 146 Comm: kworker/u8:3 Not tainted 5.17.0-rc6-dennis #79 [15.179641] Nombre del hardware: PC estándar QEMU (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 01/04/2014 [15.179641] Cola de trabajo: events_unbound btrfs_async_reclaim_data_space [btrfs] [15.179641] Rastreo de llamadas: [15.179641]  [15.179641] dump_stack_lvl+0x45/0x59 [15.179641] __lock_acquire.cold+0x217/0x2b2 [15.179641] lock_acquire+0xbf/0x2b0 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] __mutex_lock+0x8e/0x970 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? lock_is_held_type+0xd7/0x130 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? _raw_spin_unlock+0x24/0x40 [15.183838] ? btrfs_get_alloc_profile+0x106/0x230 [btrfs] [15.187601] btrfs_reserve_extent+0x131/0x260 [btrfs] [15. ---truncado---"
    }
  ],
  "lastModified": "2026-06-17T05:17:01.360",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "ABBBA66E-0244-4621-966B-9790AF1EEB00",
              "versionEndExcluding": "5.16.20",
              "versionStartIncluding": "5.16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "AE420AC7-1E59-4398-B84F-71F4B4337762",
              "versionEndExcluding": "5.17.3",
              "versionStartIncluding": "5.17"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.18:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6AD94161-84BB-42E6-9882-4FC0C42E9FC1"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}