Bluetooth: MGMT: Fix dangling pointer on mgmt_add_adv_patterns_monitor_complete

This fixes the condition checking so mgmt_pending_valid is executed
whenever status != -ECANCELED otherwise calling mgmt_pending_free(cmd)
would kfree(cmd) without unlinking it from the list first, leaving a
dangling pointer. Any subsequent list traversal (e.g.,
mgmt_pending_foreach during __mgmt_power_off, or another
mgmt_pending_valid call) would dereference freed memory.

Link: https://lore.kernel.org/linux-bluetooth/[email protected]/T/#m1418f9c82eeff8510c1beaa21cf53af20db96c06
Fixes: 302a1f6 ("Bluetooth: MGMT: Fix possible UAFs")
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
Reviewed-by: Paul Menzel <[email protected]>

Author: Vudentz

net/bluetooth/mgmt.c

@@ -5355,7 +5355,7 @@ static void mgmt_add_adv_patterns_monitor_complete(struct hci_dev *hdev,
 	 * hci_adv_monitors_clear is about to be called which will take care of
 	 * freeing the adv_monitor instances.
 	 */
-	if (status == -ECANCELED && !mgmt_pending_valid(hdev, cmd))
+	if (status == -ECANCELED || !mgmt_pending_valid(hdev, cmd))
 		return;
 
 	monitor = cmd->user_data;