Bluetooth: l2cap: fix 1 byte infoleak to userspace

Structure l2cap_options has one padding byte between max_tx and
txwin_size fields.  This byte in "opts" is copied to userspace
uninitialized.
Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/l2cap_sock.c

@@ -392,6 +392,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __us
 
 	switch (optname) {
 	case L2CAP_OPTIONS:
+		memset(&opts, 0, sizeof(opts));
 		opts.imtu     = l2cap_pi(sk)->imtu;
 		opts.omtu     = l2cap_pi(sk)->omtu;
 		opts.flush_to = l2cap_pi(sk)->flush_to;