iucv: prevent information leak in iucv_message

Initialize storage for the future IUCV header that will be included
in the transmitted packet. Some of the header fields are unused with
HiperSockets transport, and will contain data left from some other
functions.
Signed-off-by: NEugene Crosser <Eugene.Crosser@ru.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: NThomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/iucv/af_iucv.c

@@ -1031,7 +1031,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
 	struct sock *sk = sock->sk;
 	struct iucv_sock *iucv = iucv_sk(sk);
 	struct sk_buff *skb;
-	struct iucv_message txmsg;
+	struct iucv_message txmsg = {0};
 	struct cmsghdr *cmsg;
 	int cmsg_done;
 	long timeo;