In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: mgmt: Dequeue pending mesh_send_sync entries on cancel
In send_cancel(), pending mesh_tx objects are removed from the
hdev->mesh_pending list and freed via mesh_send_complete(). However, if
a mesh transmission was already queued onto hdev->cmd_sync_work_list via
mesh_next(), the queued entry retains a raw pointer to mesh_tx.
When hci_cmd_sync_work later processes the entry, it attempts to execute
mesh_send_sync and its destroy callback mesh_send_start_complete using
the already freed mesh_tx pointer, leading to a use-after-free.
Fix this by invoking hci_cmd_sync_dequeue() for mesh_send_sync on the
target mesh_tx before completing it. If the entry is found and dequeued,
its destroy callback will complete and free the object; otherwise,
mesh_send_complete() is called directly.
Additionally, ensure the transmission queue advances after cancellation
or errors. In mesh_send_start_complete(), call mesh_next() on error
unless err is -ECANCELED, because hci_cmd_sync_dequeue() holds
hdev->cmd_sync_work_lock and calling mesh_next() synchronously would
deadlock. Instead, advance the queue in send_cancel() once the lock is
released and if no transmission is in progress.
