In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: free the advertising instance on the failure and cancel paths
adv_timeout_expire() hands a kmalloc()ed instance byte to
hci_cmd_sync_queue() with a NULL destroy callback, and only
adv_timeout_expire_sync() frees it. That leaks on two paths:
-
the return value is not checked, and hci_cmd_sync_queue() does not
take ownership when it fails (-ENETDOWN, -ENODEV, -ENOMEM);
-
a cancelled entry is not released, as _hci_cmd_sync_cancel_entry()
does not free entry->data when there is no destroy callback.
hci_cmd_sync_clear() cancels every pending entry when the controller
is unregistered.
Free the buffer from a destroy callback, and in the caller when the entry
could not be queued at all.