File

mod_muc_rtbl/mod_muc_rtbl.lua @ 4813:0a257d1402c3

mod_muc_rtbl: Optimize case with zero hashes On the assumption that during quiet times between torrents of spam, the hash set would be empty. There would be no point in doing the operations and hashes to check for a match in that case.
author Kim Alvefur <zash@zash.se>
date Mon, 06 Dec 2021 18:19:19 +0100
parent 4812:9cdbb1b5e6f2
child 5173:460f78654864
line wrap: on
line source

local array = require "util.array";
local it = require "util.iterators";
local jid = require "util.jid";
local sha256 = require "util.hashes".sha256;
local set = require "util.set";
local st = require "util.stanza";

local rtbl_service_jid = assert(module:get_option_string("muc_rtbl_jid"), "No RTBL JID supplied");
local rtbl_node = module:get_option_string("muc_rtbl_node", "muc_bans_sha256");

local banned_hashes = module:shared("banned_hashes");

module:depends("pubsub_subscription");

module:add_item("pubsub-subscription", {
	service = rtbl_service_jid;
	node = rtbl_node;

	-- Callbacks:
	on_subscribed = function()
		module:log("info", "RTBL active");
	end;

	on_error = function(err)
		module:log("error", "Failed to subscribe to RTBL: %s::%s:  %s", err.type, err.condition, err.text);
	end;

	on_item = function(event)
		local hash = event.item.attr.id;
		if not hash then return; end
		module:log("debug", "Received new hash: %s", hash);
		banned_hashes[hash] = true;
	end;

	on_retract = function (event)
		local hash = event.item.attr.id;
		if not hash then return; end
		module:log("debug", "Retracted hash: %s", hash);
		banned_hashes[hash] = nil;
	end;
});

function request_list()
	local items_request = st.iq({ to = rtbl_service_jid, from = module.host, type = "get", id = "rtbl-request" })
		:tag("pubsub", { xmlns = "http://jabber.org/protocol/pubsub" })
			:tag("items", { node = rtbl_node }):up()
		:up();

	module:send(items_request);
end

function update_list(event)
	local from_jid = event.stanza.attr.from;
	if from_jid ~= rtbl_service_jid then
		module:log("debug", "Ignoring RTBL response from unknown sender");
		return;
	end
	local items_el = event.stanza:find("{http://jabber.org/protocol/pubsub}pubsub/items");
	if not items_el then
		module:log("warn", "Invalid items response from RTBL service");
		return;
	end

	local old_entries = set.new(array.collect(it.keys(banned_hashes)));

	local n_added, n_removed, n_total = 0, 0, 0;
	for item in items_el:childtags("item") do
		local hash = item.attr.id;
		if hash then
			n_total = n_total + 1;
			if not old_entries:contains(hash) then
				-- New entry
				n_added = n_added + 1;
				banned_hashes[hash] = true;
			else
				-- Entry already existed
				old_entries:remove(hash);
			end
		end
	end

	-- Remove old entries that weren't in the received list
	for hash in old_entries do
		n_removed = n_removed + 1;
		banned_hashes[hash] = nil;
	end

	module:log("info", "%d RTBL entries received from %s (%d added, %d removed)", n_total, from_jid, n_added, n_removed);
	return true;
end

module:hook("iq-result/host/rtbl-request", update_list);

module:hook("muc-occupant-pre-join", function (event)
	if next(banned_hashes) == nil then return end

	local from_bare = jid.bare(event.stanza.attr.from);

	local affiliation = event.room:get_affiliation(from_bare);
	if affiliation and affiliation ~= "none" then
		-- Skip check for affiliated users
		return;
	end

	local bare_hash = sha256(jid.bare(event.stanza.attr.from), true);
	local host_hash = sha256(jid.host(event.stanza.attr.from), true);
	if banned_hashes[bare_hash] or banned_hashes[host_hash] then
		module:log("info", "Blocked user <%s> from room <%s> due to RTBL match", from_bare, event.stanza.attr.to);
		local error_reply = st.error_reply(event.stanza, "cancel", "forbidden", "You are banned from this service", event.room.jid);
		event.origin.send(error_reply);
		return true;
	end
end);

if prosody.start_time then
	request_list();
else
	module:hook_global("server-started", function ()
		request_list();
	end);
end