dynsec: Fix listClients/getClient crashing if an anon user present

This only affects the unreleased `develop` branch.

plugins/dynamic-security/clients.c

@@ -915,18 +915,21 @@ static int dynsec__remove_client_from_all_groups(struct dynsec__data *data, cons
 static int dynsec__add_client_address(const struct mosquitto *client, void *context_ptr)
 {
 	struct connection_array_context *functor_context = (struct connection_array_context*)context_ptr;
+	const char *username = mosquitto_client_username(client);
+
+	if((username == NULL && functor_context->username == NULL)
+			|| (username && functor_context->username && !strcmp(functor_context->username, username))){
 
-	if(!strcmp(functor_context->username,mosquitto_client_username(client))){
 		cJSON *j_connection = cJSON_CreateObject();
 		const char *address;
 		if(!j_connection){
 			return MOSQ_ERR_NOMEM;
 		}
-		if((address=mosquitto_client_address(client)) && !cJSON_AddStringToObject(j_connection,"address",address)){
+		if((address = mosquitto_client_address(client)) && !cJSON_AddStringToObject(j_connection, "address", address)){
 			cJSON_Delete(j_connection);
 			return MOSQ_ERR_NOMEM;
 		}
-		cJSON_AddItemToArray(functor_context->j_connections,j_connection);
+		cJSON_AddItemToArray(functor_context->j_connections, j_connection);
 	}
 	return MOSQ_ERR_SUCCESS;
 }

test/broker/14-dynsec-client.py

@@ -67,6 +67,9 @@ rc = 1
 connect_packet = mosq_test.gen_connect("ctrl-test", username="admin", password="admin")
 connack_packet = mosq_test.gen_connack(rc=0)
 
+anon_connect_packet = mosq_test.gen_connect("anon-helper")
+anon_connack_packet = mosq_test.gen_connack(rc=0)
+
 mid = 2
 subscribe_packet = mosq_test.gen_subscribe(mid, "$CONTROL/dynamic-security/#", 1)
 suback_packet = mosq_test.gen_suback(mid, 1)
@@ -80,6 +83,9 @@ except FileExistsError:
 broker = mosq_test.start_broker(filename=os.path.basename(__file__), use_conf=True, port=port)
 
 try:
+    # The anon user is used to ensure that when the commands are run they are also valid if an anon user is present.
+    anon_sock = mosq_test.do_client_connect(anon_connect_packet, anon_connack_packet, timeout=5, port=port)
+
     sock = mosq_test.do_client_connect(connect_packet, connack_packet, timeout=5, port=port)
     mosq_test.do_send_receive(sock, subscribe_packet, suback_packet, "suback")
 
@@ -124,6 +130,7 @@ try:
     rc = broker_terminate_rc
 
     sock.close()
+    anon_sock.close()
 except mosq_test.TestError:
     pass
 finally: