plugins/mod_announce.lua
author Jonas Schäfer <jonas@wielicki.name>
Mon, 10 Jan 2022 18:23:54 +0100
branch0.11
changeset 12185 783056b4e448
parent 10030 1117138fa372
child 10549 2fbcdf6da331
permissions -rw-r--r--
util.xml: Do not allow doctypes, comments or processing instructions Yes. This is as bad as it sounds. CVE pending. In Prosody itself, this only affects mod_websocket, which uses util.xml to parse the <open/> frame, thus allowing unauthenticated remote DoS using Billion Laughs. However, third-party modules using util.xml may also be affected by this. This commit installs handlers which disallow the use of doctype declarations and processing instructions without any escape hatch. It, by default, also introduces such a handler for comments, however, there is a way to enable comments nontheless. This is because util.xml is used to parse human-facing data, where comments are generally a desirable feature, and also because comments are generally harmless.

-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local st, jid = require "util.stanza", require "util.jid";

local hosts = prosody.hosts;
local is_admin = require "core.usermanager".is_admin;

function send_to_online(message, host)
	local sessions;
	if host then
		sessions = { [host] = hosts[host] };
	else
		sessions = hosts;
	end

	local c = 0;
	for hostname, host_session in pairs(sessions) do
		if host_session.sessions then
			message.attr.from = hostname;
			for username in pairs(host_session.sessions) do
				c = c + 1;
				message.attr.to = username.."@"..hostname;
				module:send(message);
			end
		end
	end

	return c;
end


-- Old <message>-based jabberd-style announcement sending
function handle_announcement(event)
	local stanza = event.stanza;
	local node, host, resource = jid.split(stanza.attr.to);

	if resource ~= "announce/online" then
		return; -- Not an announcement
	end

	if not is_admin(stanza.attr.from, host) then
		-- Not an admin? Not allowed!
		module:log("warn", "Non-admin '%s' tried to send server announcement", stanza.attr.from);
		return;
	end

	module:log("info", "Sending server announcement to all online users");
	local message = st.clone(stanza);
	message.attr.type = "headline";
	message.attr.from = host;

	local c = send_to_online(message, host);
	module:log("info", "Announcement sent to %d online users", c);
	return true;
end
module:hook("message/host", handle_announcement);

-- Ad-hoc command (XEP-0133)
local dataforms_new = require "util.dataforms".new;
local announce_layout = dataforms_new{
	title = "Making an Announcement";
	instructions = "Fill out this form to make an announcement to all\nactive users of this service.";

	{ name = "FORM_TYPE", type = "hidden", value = "http://jabber.org/protocol/admin" };
	{ name = "subject", type = "text-single", label = "Subject" };
	{ name = "announcement", type = "text-multi", required = true, label = "Announcement" };
};

function announce_handler(_, data, state)
	if state then
		if data.action == "cancel" then
			return { status = "canceled" };
		end

		local fields = announce_layout:data(data.form);

		module:log("info", "Sending server announcement to all online users");
		local message = st.message({type = "headline"}, fields.announcement):up()
			:tag("subject"):text(fields.subject or "Announcement");

		local count = send_to_online(message, data.to);

		module:log("info", "Announcement sent to %d online users", count);
		return { status = "completed", info = ("Announcement sent to %d online users"):format(count) };
	else
		return { status = "executing", actions = {"next", "complete", default = "complete"}, form = announce_layout }, "executing";
	end
end

module:depends "adhoc";
local adhoc_new = module:require "adhoc".new;
local announce_desc = adhoc_new("Send Announcement to Online Users", "http://jabber.org/protocol/admin#announce", announce_handler, "admin");
module:provides("adhoc", announce_desc);