Diff

--- a/plugins/mod_register.lua	Wed Dec 23 11:43:39 2015 +0100
+++ b/plugins/mod_register.lua	Sun Dec 27 12:29:28 2015 +0100
@@ -13,9 +13,10 @@
 local usermanager_create_user = require "core.usermanager".create_user;
 local usermanager_set_password = require "core.usermanager".set_password;
 local usermanager_delete_user = require "core.usermanager".delete_user;
-local os_time = os.time;
 local nodeprep = require "util.encodings".stringprep.nodeprep;
 local jid_bare = require "util.jid".bare;
+local create_throttle = require "util.throttle".create;
+local new_cache = require "util.cache".new;
 
 local compat = module:get_option_boolean("registration_compat", true);
 local allow_registration = module:get_option_boolean("allow_registration", false);
@@ -84,6 +85,7 @@
 
 local function handle_registration_stanza(event)
 	local session, stanza = event.origin, event.stanza;
+	local log = session.log or module._log;
 
 	local query = stanza.tags[1];
 	if stanza.attr.type == "get" then
@@ -97,6 +99,7 @@
 		if query.tags[1] and query.tags[1].name == "remove" then
 			local username, host = session.username, session.host;
 
+			-- This one weird trick sends a reply to this stanza before the user is deleted
 			local old_session_close = session.close;
 			session.close = function(session, ...)
 				session.send(st.reply(stanza));
@@ -106,13 +109,13 @@
 			local ok, err = usermanager_delete_user(username, host);
 
 			if not ok then
-				module:log("debug", "Removing user account %s@%s failed: %s", username, host, err);
+				log("debug", "Removing user account %s@%s failed: %s", username, host, err);
 				session.close = old_session_close;
 				session.send(st.error_reply(stanza, "cancel", "service-unavailable", err));
 				return true;
 			end
 
-			module:log("info", "User removed their account: %s@%s", username, host);
+			log("info", "User removed their account: %s@%s", username, host);
 			module:fire_event("user-deregistered", { username = username, host = host, source = "mod_register", session = session });
 		else
 			local username = nodeprep(query:get_child_text("username"));
@@ -169,14 +172,36 @@
 	end
 end
 
-local recent_ips = {};
 local min_seconds_between_registrations = module:get_option_number("min_seconds_between_registrations");
 local whitelist_only = module:get_option_boolean("whitelist_registration_only");
 local whitelisted_ips = module:get_option_set("registration_whitelist", { "127.0.0.1" })._items;
 local blacklisted_ips = module:get_option_set("registration_blacklist", {})._items;
 
+local throttle_max = module:get_option_number("registration_throttle_max", min_seconds_between_registrations and 1);
+local throttle_period = module:get_option_number("registration_throttle_period", min_seconds_between_registrations);
+local throttle_cache_size = module:get_option_number("registration_throttle_cache_size", 100);
+local blacklist_overflow = module_get_option_boolean("blacklist_on_registration_throttle_overload", false);
+
+local throttle_cache = new_cache(throttle_cache_size, blacklist_overflow and function (ip, throttle)
+	if not throttle:peek() then
+		module:log("info", "Adding ip %s to registration blacklist", ip);
+		blacklisted_ips[ip] = true;
+	end
+end);
+
+local function check_throttle(ip)
+	if not throttle_max then return true end
+	local throttle = throttle_cache:get(ip);
+	if not throttle then
+		throttle = create_throttle(throttle_max, throttle_period);
+	end
+	throttle_cache:set(ip, throttle);
+	return throttle:poll(1);
+end
+
 module:hook("stanza/iq/jabber:iq:register:query", function(event)
 	local session, stanza = event.origin, event.stanza;
+	local log = session.log or module._log;
 
 	if not(allow_registration) or session.type ~= "c2s_unauthed" then
 		session.send(st.error_reply(stanza, "cancel", "service-unavailable"));
@@ -196,23 +221,14 @@
 				else
 					-- Check that the user is not blacklisted or registering too often
 					if not session.ip then
-						module:log("debug", "User's IP not known; can't apply blacklist/whitelist");
+						log("debug", "User's IP not known; can't apply blacklist/whitelist");
 					elseif blacklisted_ips[session.ip] or (whitelist_only and not whitelisted_ips[session.ip]) then
 						session.send(st.error_reply(stanza, "cancel", "not-acceptable", "You are not allowed to register an account."));
 						return true;
 					elseif min_seconds_between_registrations and not whitelisted_ips[session.ip] then
-						if not recent_ips[session.ip] then
-							recent_ips[session.ip] = { time = os_time(), count = 1 };
-						else
-							local ip = recent_ips[session.ip];
-							ip.count = ip.count + 1;
-
-							if os_time() - ip.time < min_seconds_between_registrations then
-								ip.time = os_time();
-								session.send(st.error_reply(stanza, "wait", "not-acceptable"));
-								return true;
-							end
-							ip.time = os_time();
+						if check_throttle(session.ip) then
+							session.send(st.error_reply(stanza, "wait", "not-acceptable"));
+							return true;
 						end
 					end
 					local username, password = nodeprep(data.username), data.password;
@@ -238,7 +254,7 @@
 								return true;
 							end
 							session.send(st.reply(stanza)); -- user created!
-							module:log("info", "User account created: %s@%s", username, host);
+							log("info", "User account created: %s@%s", username, host);
 							module:fire_event("user-registered", {
 								username = username, host = host, source = "mod_register",
 								session = session });