me: Avoid crash when processing endpoint with invalid NO_FAMILY

Such endpoints are used to request a peer reflexive endpoint, but are
never expected in a response.

Fixes: d5cc175833 ("experimental P2P-NAT-T for IKEv2 merged back from branch")

src/libcharon/sa/ikev2/connect_manager.c

@@ -1262,13 +1262,12 @@ static void process_response(private_connect_manager_t *this, check_t *check,
 		linked_list_t *local_endpoints = checklist->is_initiator ?
 			checklist->initiator.endpoints : checklist->responder.endpoints;
 
+		host_t *host = check->endpoint->get_host(check->endpoint);
 		endpoint_notify_t *local_endpoint;
-		if (!endpoints_contain(local_endpoints,
-							   check->endpoint->get_host(check->endpoint),
-							   &local_endpoint))
+		if (host && !endpoints_contain(local_endpoints, host, &local_endpoint))
 		{
 			local_endpoint = endpoint_notify_create_from_host(PEER_REFLEXIVE,
-					check->endpoint->get_host(check->endpoint), pair->local);
+															  host, pair->local);
 			local_endpoint->set_priority(local_endpoint,
 								check->endpoint->get_priority(check->endpoint));
 			local_endpoints->insert_last(local_endpoints, local_endpoint);

src/libcharon/sa/ikev2/tasks/ike_me.c

@@ -477,8 +477,12 @@ METHOD(task_t, process_i, status_t,
 			{	/* FIXME: should we accept this endpoint even if we did not send
 				 * a request? */
 				host_t *endpoint = reflexive->get_host(reflexive);
-				endpoint = endpoint->clone(endpoint);
-				this->ike_sa->set_server_reflexive_host(this->ike_sa, endpoint);
+				if (endpoint)
+				{
+					endpoint = endpoint->clone(endpoint);
+					this->ike_sa->set_server_reflexive_host(this->ike_sa,
+															endpoint);
+				}
 			}
 			break;
 		}