CVE-2022-50833

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

Bluetooth: use hdev->workqueue when queuing hdev->{cmd,ncmd}_timer works

syzbot is reporting attempt to schedule hdev->cmd_work work from system_wq WQ into hdev->workqueue WQ which is under draining operation [1], for commit c8efcc2589464ac7 (workqueue: allow chained queueing during destruction) does not allow such operation.

The check introduced by commit 877afadad2dce8aa (Bluetooth: When HCI work queue is drained, only queue chained work) was incomplete.

Use hdev->workqueue WQ when queuing hdev->{cmd,ncmd}timer works because hci{cmd,ncmd}_timeout() calls queue_work(hdev->workqueue). Also, protect the queuing operation with RCU read lock in order to avoid calling queue_delayed_work() after cancel_delayed_work() completed.

Affected Software

References

• https://git.kernel.org/stable/c/3c6b036fe5c8ed8b6c4cbdc03605929882907ef0
• https://git.kernel.org/stable/c/c4635cf3d845a7324c25c52d549b70c8bd7ad4c7
• https://git.kernel.org/stable/c/deee93d13d385103205879a8a0915036ecd83261