Allow sending an empty password to drop settings_access

src/console_cmds.cpp

@@ -730,6 +730,7 @@ DEF_CONSOLE_CMD(ConSettingsAccess)
 {
 	if (argc == 0) {
 		IConsoleHelp("Enable changing game settings from this client. Usage: 'settings_access <password>'");
+		IConsoleHelp("Send an empty password \"\" to drop access");
 		return true;
 	}
 

src/network/network_client.cpp

@@ -459,7 +459,11 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::SendCompanyPassword(const char
 NetworkRecvStatus ClientNetworkGameSocketHandler::SendSettingsPassword(const char *password)
 {
 	Packet *p = new Packet(PACKET_CLIENT_SETTINGS_PASSWORD);
-	p->Send_string(GenerateCompanyPasswordHash(password, _password_server_id, _settings_password_game_seed));
+	if (StrEmpty(password)) {
+		p->Send_string("");
+	} else {
+		p->Send_string(GenerateCompanyPasswordHash(password, _password_server_id, _settings_password_game_seed));
+	}
 	my_client->SendPacket(p);
 	return NETWORK_RECV_STATUS_OKAY;
 }

src/network/network_server.cpp

@@ -1055,7 +1055,10 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_SETTINGS_PASSWO
 	p->Recv_string(password, sizeof(password));
 
 	/* Check settings password. Deny if no password is set */
-	if (StrEmpty(_settings_client.network.settings_password) ||
+	if (StrEmpty(password)) {
+		if (this->settings_authed) DEBUG(net, 0, "[settings-ctrl] client-id %d deauthed", this->client_id);
+		this->settings_authed = false;
+	} else if (StrEmpty(_settings_client.network.settings_password) ||
 			strcmp(password, GenerateCompanyPasswordHash(_settings_client.network.settings_password, _settings_client.network.network_id, _settings_game.game_creation.generation_seed ^ this->settings_hash_bits)) != 0) {
 		DEBUG(net, 0, "[settings-ctrl] wrong password from client-id %d", this->client_id);
 		this->settings_authed = false;