[IPV4]: Fix DST leak in icmp_push_reply()

Based upon a bug report and initial patch by
Ollie Wild.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/icmp.c

@@ -349,12 +349,12 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
 {
 	struct sk_buff *skb;
 
-	ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param,
+	if (ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param,
 		           icmp_param->data_len+icmp_param->head_len,
 		           icmp_param->head_len,
-		       ipc, rt, MSG_DONTWAIT);
-
-	if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) {
+		           ipc, rt, MSG_DONTWAIT) < 0)
+		ip_flush_pending_frames(icmp_socket->sk);
+	else if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) {
 		struct icmphdr *icmph = skb->h.icmph;
 		unsigned int csum = 0;
 		struct sk_buff *skb1;