CVE-2024-26758 Information

Apr 04, 2024 cve

Description

In the Linux kernel the following vulnerability has been resolved:

md: Don’t ignore suspended array in md_check_recovery()

mddev_suspend() never stop sync_thread hence it doesn’t make sense to ignore suspended array in md_check_recovery() which might cause sync_thread can’t be unregistered.

After commit f52f5c71f3d4 (\md: fix stopping sync thread) following hang can be triggered by test shell/integrity-caching.sh:

  1. suspend the array: raid_postsuspend mddev_suspend

  2. stop the array: raid_dtr md_stop __md_stop_writes 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))

  3. sync thread done: md_do_sync set_bit(MD_RECOVERY_DONE &mddev->recovery); md_wakeup_thread(mddev->thread);

  4. daemon thread can’t unregister sync thread: md_check_recovery if (mddev->suspended) return; -> return directly md_read_sync_thread clear_bit(MD_RECOVERY_RUNNING &mddev->recovery); -> MD_RECOVERY_RUNNING can’t be cleared hence step 2 hang;

This problem is not just related to dm-raid fix it by ignoring suspended array in md_check_recovery(). And follow up patches will improve dm-raid better to frozen sync thread during suspend.

Reference

https://git.kernel.org/stable/c/a55f0d6179a19c6b982e2dc344d58c98647a3be0 https://git.kernel.org/stable/c/1baae052cccd08daf9a9d64c3f959d8cdb689757

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