Per listener allow_anonymous.

ChangeLog.txt

@@ -64,6 +64,12 @@ Broker:
   Closes #8.
 - Add set_tcp_nodelay option to allow Nagle's algorithm to be disabled on
   client sockets. Closes #433.
+- The behaviour of allow_anonymous has changed. In the old behaviour, the
+  default if not set was to allow anonymous access. The new behaviour is to
+  default is to allow anonymous access unless another security option is set.
+  For example, if password_file is set and allow_anonymous is not set, then
+  anonymous access will be denied. It is still possible to allow anonymous
+  access by setting it explicitly.
 
 Client library:
 - Outgoing messages with QoS>1 are no longer retried after a timeout period.

man/mosquitto.conf.5.xml

@@ -161,8 +161,12 @@
 						connect without providing a username are allowed to
 						connect. If set to <replaceable>false</replaceable>
 						then another means of connection should be created to
-						control authenticated client access.  Defaults to
-						<replaceable>true</replaceable>.</para>
+						control authenticated client access.</para>
+					<para>Defaults to <replaceable>true</replaceable> if no
+						other security options are set. If any other
+						authentication options are set, then
+						<option>allow_anonymous</option> defaults to
+						<replaceable>false</replaceable>.</para>
 					<para>Reloaded on reload signal.</para>
 				</listitem>
 			</varlistentry>

mosquitto.conf

@@ -141,7 +141,7 @@
 # options are controlled on a per listener basis. The following options are
 # affected:
 #
-# password_file acl_file psk_file auth_plugin auth_opt_*
+# password_file acl_file psk_file auth_plugin auth_opt_* allow_anonymous
 #
 # The default behaviour is for this to be set to false, which maintains the 
 # setting behaviour from previous versions of mosquitto.
@@ -543,7 +543,10 @@
 # without providing a username are allowed to connect. If set to 
 # false then a password file should be created (see the 
 # password_file option) to control authenticated client access. 
-# Defaults to true.
+#
+# Defaults to true if no other security options are set. If any other
+# authentication options are set, then allow_anonymous defaults to false.
+#
 #allow_anonymous true
 
 # -----------------------------------------------------------------

src/conf.c

@@ -150,7 +150,7 @@ static void config__init_reload(struct mosquitto__config *config)
 	/* Set defaults */
 	mosquitto__free(config->acl_file);
 	config->acl_file = NULL;
-	config->security_options.allow_anonymous = true;
+	config->security_options.allow_anonymous = -1;
 	config->allow_duplicate_messages = false;
 	config->allow_zero_length_clientid = true;
 	config->auto_id_prefix = NULL;
@@ -524,9 +524,7 @@ int config__read(struct mosquitto__config *config, bool reload)
 	struct config_recurse cr;
 	int lineno = 0;
 	int len;
-#ifdef WITH_BRIDGE
 	int i;
-#endif
 
 	cr.log_dest = MQTT3_LOG_NONE;
 	cr.log_dest_set = 0;
@@ -549,6 +547,40 @@ int config__read(struct mosquitto__config *config, bool reload)
 		return rc;
 	}
 
+	/* If auth/access options are set and allow_anonymous not explicitly set, disallow anon. */
+	if(config->per_listener_settings){
+		for(i=0; i<config->listener_count; i++){
+			if(config->listeners[i].security_options.allow_anonymous == -1){
+				if(config->listeners[i].security_options.password_file
+					|| config->listeners[i].security_options.psk_file
+					|| config->listeners[i].security_options.auth_plugins){
+
+					/* allow_anonymous not set explicitly, some other security options
+					* have been set - so disable allow_anonymous
+					*/
+					config->listeners[i].security_options.allow_anonymous = false;
+				}else{
+					/* Default option if no security options set */
+					config->listeners[i].security_options.allow_anonymous = true;
+				}
+			}
+		}
+	}else{
+		if(config->security_options.allow_anonymous == -1){
+			if(config->security_options.password_file
+				 || config->security_options.psk_file
+				 || config->security_options.auth_plugins){
+
+				/* allow_anonymous not set explicitly, some other security options
+				* have been set - so disable allow_anonymous
+				*/
+				config->security_options.allow_anonymous = false;
+			}else{
+				/* Default option if no security options set */
+				config->security_options.allow_anonymous = true;
+			}
+		}
+	}
 #ifdef WITH_PERSISTENCE
 	if(config->persistence){
 		if(!config->persistence_file){
@@ -697,7 +729,7 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, const
 #endif
 				}else if(!strcmp(token, "allow_anonymous")){
 					conf__set_cur_security_options(config, cur_listener, &cur_security_options);
-					if(conf__parse_bool(&token, "allow_anonymous", &cur_security_options->allow_anonymous, saveptr)) return MOSQ_ERR_INVAL;
+					if(conf__parse_bool(&token, "allow_anonymous", (bool *)&cur_security_options->allow_anonymous, saveptr)) return MOSQ_ERR_INVAL;
 				}else if(!strcmp(token, "allow_duplicate_messages")){
 					if(conf__parse_bool(&token, "allow_duplicate_messages", &config->allow_duplicate_messages, saveptr)) return MOSQ_ERR_INVAL;
 				}else if(!strcmp(token, "allow_zero_length_clientid")){
@@ -1184,7 +1216,7 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, const
 						}
 						cur_listener = &config->listeners[config->listener_count-1];
 						memset(cur_listener, 0, sizeof(struct mosquitto__listener));
-						cur_listener->security_options.allow_anonymous = true;
+						cur_listener->security_options.allow_anonymous = -1;
 						cur_listener->protocol = mp_mqtt;
 						cur_listener->port = tmp_int;
 						token = strtok_r(NULL, "", &saveptr);

src/mosquitto_broker_internal.h

@@ -147,11 +147,15 @@ struct mosquitto__auth_plugin_config
 };
 
 struct mosquitto__security_options {
+	/* Any options that get added here also need considering
+	 * in config__read() with regards whether allow_anonymous
+	 * should be disabled when these options are set.
+	 */
 	char *password_file;
 	char *psk_file;
 	struct mosquitto__auth_plugin_config *auth_plugins;
 	int auth_plugin_count;
-	bool allow_anonymous;
+	char allow_anonymous;
 };
 
 struct mosquitto__listener {