Fix payload check

plugins/examples/Makefile

@@ -7,6 +7,7 @@ DIRS= \
 		delayed-auth \
 		force-retain \
 		message-timestamp \
+		payload-ban \
 		payload-modification \
 		payload-size-stats \
 		plugin-event-stats \

plugins/examples/payload-ban/mosquitto_payload_ban.c

@@ -101,8 +101,8 @@ static int acl_check_callback(int event, void *event_data, void *userdata)
 	UNUSED(event);
 	UNUSED(userdata);
 
-	if(ed->payload && ed->payloadlen){
-		if(!strncmp(ed->payload, "Tired of using an old outdated MQTT client", ed->payloadlen)){
+	if(ed->payload && ed->payloadlen > sizeof("Tired of using an old outdated MQTT client")){
+		if(!strncmp(ed->payload, "Tired of using an old outdated MQTT client", strlen("Tired of using an old outdated MQTT client"))){
 			ip_address = mosquitto_client_address(ed->client);
 			clientid = mosquitto_client_id(ed->client);