Bluetooth: fix oops in l2cap_connect_req

In error cases when the ACL is insecure or we fail to allocate a new
struct sock, we jump to the "response" label.  If so, "sk" will be
null and the kernel crashes.

Signed-off-by: Nathan Holstein <nathan.holstein@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/l2cap.c

@@ -2891,7 +2891,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
 	struct l2cap_chan_list *list = &conn->chan_list;
 	struct l2cap_conn_req *req = (struct l2cap_conn_req *) data;
 	struct l2cap_conn_rsp rsp;
-	struct sock *parent, *uninitialized_var(sk);
+	struct sock *parent, *sk = NULL;
 	int result, status = L2CAP_CS_NO_INFO;
 
 	u16 dcid = 0, scid = __le16_to_cpu(req->scid);
@@ -3000,7 +3000,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
 					L2CAP_INFO_REQ, sizeof(info), &info);
 	}
 
-	if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_REQ_SENT) &&
+	if (sk && !(l2cap_pi(sk)->conf_state & L2CAP_CONF_REQ_SENT) &&
 				result == L2CAP_CR_SUCCESS) {
 		u8 buf[128];
 		l2cap_pi(sk)->conf_state |= L2CAP_CONF_REQ_SENT;