Bluetooth: RFCOMM - Fix info leak via getsockname()

The RFCOMM code fails to initialize the trailing padding byte of struct
sockaddr_rc added for alignment. It that for leaks one byte kernel stack
via the getsockname() syscall. Add an explicit memset(0) before filling
the structure to avoid the info leak.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
void __exit rfcomm_cleanup_sockets(void)
{
	debugfs_remove(rfcomm_sock_debugfs);

	if (bt_sock_unregister(BTPROTO_RFCOMM) < 0)
		BT_ERR("RFCOMM socket layer unregistration failed");

	proto_unregister(&rfcomm_proto);
}

void __exit rfcomm_cleanup_sockets(void)
{
	debugfs_remove(rfcomm_sock_debugfs);

	if (bt_sock_unregister(BTPROTO_RFCOMM) < 0)
		BT_ERR("RFCOMM socket layer unregistration failed");

	proto_unregister(&rfcomm_proto);
}
