Double check if we have a packet before retransmitting it

src/libcharon/sa/task_manager_v1.c

@@ -871,7 +871,7 @@ METHOD(task_manager_t, process_message, status_t,
 	else
 	{
 		hash = chunk_hash(msg->get_packet_data(msg));
-		if (hash == this->responding.hash)
+		if (hash == this->responding.hash && this->responding.packet)
 		{
 			DBG1(DBG_IKE, "received retransmit of request with ID %d, "
 				 "retransmitting response", mid);