File

plugins/muc/hats.lib.lua @ 12180:53e0ae770917

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.
author Jonas Schäfer <jonas@wielicki.name>
date Mon, 10 Jan 2022 18:23:54 +0100
parent 11245:43b43e7156b8
child 12977:74b9e05af71e
line wrap: on
line source

local st = require "util.stanza";
local muc_util = module:require "muc/util";

local xmlns_hats = "xmpp:prosody.im/protocol/hats:1";

-- Strip any hats claimed by the client (to prevent spoofing)
muc_util.add_filtered_namespace(xmlns_hats);


module:hook("muc-build-occupant-presence", function (event)
	local bare_jid = event.occupant and event.occupant.bare_jid or event.bare_jid;
	local aff_data = event.room:get_affiliation_data(bare_jid);
	local hats = aff_data and aff_data.hats;
	if not hats then return; end
	local hats_el;
	for hat_id, hat_data in pairs(hats) do
		if hat_data.active then
			if not hats_el then
				hats_el = st.stanza("hats", { xmlns = xmlns_hats });
			end
			hats_el:tag("hat", { uri = hat_id, title = hat_data.title }):up();
		end
	end
	if not hats_el then return; end
	event.stanza:add_direct_child(hats_el);
end);