Bluetooth: HCI - Fix info leak in getsockopt(HCI_FILTER)

The HCI code fails to initialize the two padding bytes of struct
hci_ufilter before copying it to userland -- that for leaking two
bytes kernel stack. 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>
static int hci_sock_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct hci_dev *hdev;

	BT_DBG("sock %p sk %p", sock, sk);

	if (!sk)
		return 0;

	hdev = hci_pi(sk)->hdev;

	if (hci_pi(sk)->channel == HCI_CHANNEL_MONITOR)
		atomic_dec(&monitor_promisc);

	bt_sock_unlink(&hci_sk_list, sk);

	if (hdev) {
		atomic_dec(&hdev->promisc);
		hci_dev_put(hdev);
	}

	sock_orphan(sk);

	skb_queue_purge(&sk->sk_receive_queue);
	skb_queue_purge(&sk->sk_write_queue);

	sock_put(sk);
	return 0;
}

static int hci_sock_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct hci_dev *hdev;

	BT_DBG("sock %p sk %p", sock, sk);

	if (!sk)
		return 0;

	hdev = hci_pi(sk)->hdev;

	if (hci_pi(sk)->channel == HCI_CHANNEL_MONITOR)
		atomic_dec(&monitor_promisc);

	bt_sock_unlink(&hci_sk_list, sk);

	if (hdev) {
		atomic_dec(&hdev->promisc);
		hci_dev_put(hdev);
	}

	sock_orphan(sk);

	skb_queue_purge(&sk->sk_receive_queue);
	skb_queue_purge(&sk->sk_write_queue);

	sock_put(sk);
	return 0;
}
