Use correct size for hci_filter type

[sooda]

This is for tag 0.5.5, not the master branch, but github doesn't let me create a PR with the tag as a base. Anyway... My proposed fix for issue 383.

Use 16 bytes for the filter structure in set_socket_filter(), not 14.

struct hci_filter unfortunately is not a packed struct:

https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/lib/hci.h

Hence, it has two bytes of padding at the end for correct stride of the 32-bit members.

This used to not be a problem until Linux kernel commit b2186061d6043 (Bluetooth: hci_sock: Fix not validating setsockopt user input) changed the behaviour of HCI_FILTER sockopt; before, the kernel would have truncated the read size but now the data supplied has to be at least the struct size, or we'd get -EINVAL.

[qdot]

That's not a version we're maintaining anymore, so I guess I'll let this hang out but I have nowhere to merge it.