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CVE-2022-48734

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <26b3901d20bf9da2c6a00cb1fb48932166f80a45, <31198e58c09e21d4f65c49d2361f76b87aca4c3f, 0, 4.4, <=5.10.*, <89d4cca583fc9594ee7d1a0bc986886d6fb587e6, <=5.4.*, 5.4.178, 5.10.99, <=5.16.*, <32747e01436aac8ef93fe85b5b523b4f3b52f040, <e804861bd4e69cc5fe1053eedcb024982dde8e48, <=*, <=5.15.*, 967ef5131e42d6e3bb216c44161d893048a49957, 5.17, 5.15.22, 5.16.8, <4.4

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix deadlock between quota disable and qgroup rescan worker Quota disable ioctl starts a transaction before waiting for the qgroup rescan worker completes. However, this wait can be infinite and results in deadlock because of circular dependency among the quota disable ioctl, the qgroup rescan worker and the other task with transaction such as block group relocation task. The deadlock happens with the steps following: 1) Task A calls ioctl to disable quota. It starts a transaction and waits for qgroup rescan worker completes. 2) Task B such as block group relocation task starts a transaction and joins to the transaction that task A started. Then task B commits to the transaction. In this commit, task B waits for a commit by task A. 3) Task C as the qgroup rescan worker starts its job and starts a transaction. In this transaction start, task C waits for completion of the transaction that task A started and task B committed. This deadlock was found with fstests test case btrfs/115 and a zoned null_blk device. The test case enables and disables quota, and the block group reclaim was triggered during the quota disable by chance. The deadlock was also observed by running quota enable and disable in parallel with 'btrfs balance' command on regular null_blk devices. An example report of the deadlock: [372.469894] INFO: task kworker/u16:6:103 blocked for more than 122 seconds. [372.479944] Not tainted 5.16.0-rc8 #7 [372.485067] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [372.493898] task:kworker/u16:6 state:D stack: 0 pid: 103 ppid: 2 flags:0x00004000 [372.503285] Workqueue: btrfs-qgroup-rescan btrfs_work_helper [btrfs] [372.510782] Call Trace: [372.514092] <TASK> [372.521684] __schedule+0xb56/0x4850 [372.530104] ? io_schedule_timeout+0x190/0x190 [372.538842] ? lockdep_hardirqs_on+0x7e/0x100 [372.547092] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [372.555591] schedule+0xe0/0x270 [372.561894] btrfs_commit_transaction+0x18bb/0x2610 [btrfs] [372.570506] ? btrfs_apply_pending_changes+0x50/0x50 [btrfs] [372.578875] ? free_unref_page+0x3f2/0x650 [372.585484] ? finish_wait+0x270/0x270 [372.591594] ? release_extent_buffer+0x224/0x420 [btrfs] [372.599264] btrfs_qgroup_rescan_worker+0xc13/0x10c0 [btrfs] [372.607157] ? lock_release+0x3a9/0x6d0 [372.613054] ? btrfs_qgroup_account_extent+0xda0/0xda0 [btrfs] [372.620960] ? do_raw_spin_lock+0x11e/0x250 [372.627137] ? rwlock_bug.part.0+0x90/0x90 [372.633215] ? lock_is_held_type+0xe4/0x140 [372.639404] btrfs_work_helper+0x1ae/0xa90 [btrfs] [372.646268] process_one_work+0x7e9/0x1320 [372.652321] ? lock_release+0x6d0/0x6d0 [372.658081] ? pwq_dec_nr_in_flight+0x230/0x230 [372.664513] ? rwlock_bug.part.0+0x90/0x90 [372.670529] worker_thread+0x59e/0xf90 [372.676172] ? process_one_work+0x1320/0x1320 [372.682440] kthread+0x3b9/0x490 [372.687550] ? _raw_spin_unlock_irq+0x24/0x50 [372.693811] ? set_kthread_struct+0x100/0x100 [372.700052] ret_from_fork+0x22/0x30 [372.705517] </TASK> [372.709747] INFO: task btrfs-transacti:2347 blocked for more than 123 seconds. [372.729827] Not tainted 5.16.0-rc8 #7 [372.745907] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [372.767106] task:btrfs-transacti state:D stack: 0 pid: 2347 ppid: 2 flags:0x00004000 [372.787776] Call Trace: [372.801652] <TASK> [372.812961] __schedule+0xb56/0x4850 [372.830011] ? io_schedule_timeout+0x190/0x190 [372.852547] ? lockdep_hardirqs_on+0x7e/0x100 [372.871761] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [372.886792] schedule+0xe0/0x270 [372.901685] wait_current_trans+0x22c/0x310 [btrfs] [372.919743] ? btrfs_put_transaction+0x3d0/0x3d0 [btrfs] [372.938923] ? finish_wait+0x270/0x270 [372.959085] ? join_transaction+0xc7 ---truncated---

Gravité et risque d'exploitation

CVE-2022-48734 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.18 %, ce qui la place devant 6.9 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <26b3901d20bf9da2c6a00cb1fb48932166f80a45, <31198e58c09e21d4f65c49d2361f76b87aca4c3f, 0, 4.4, <=5.10.*, <89d4cca583fc9594ee7d1a0bc986886d6fb587e6, <=5.4.*, 5.4.178, 5.10.99, <=5.16.*, <32747e01436aac8ef93fe85b5b523b4f3b52f040, <e804861bd4e69cc5fe1053eedcb024982dde8e48, <=*, <=5.15.*, 967ef5131e42d6e3bb216c44161d893048a49957, 5.17, 5.15.22, 5.16.8, <4.4) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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