File

plugins/mod_mam/mamprefsxml.lib.lua @ 12181:783056b4e448 0.11 0.11.12

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 9728:d41ce505cdf9
child 12977:74b9e05af71e
line wrap: on
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-- Prosody IM
-- Copyright (C) 2008-2017 Matthew Wild
-- Copyright (C) 2008-2017 Waqas Hussain
-- Copyright (C) 2011-2017 Kim Alvefur
-- Copyright (C) 2018 Emmanuel Gil Peyrot
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
-- XEP-0313: Message Archive Management for Prosody
--

local st = require"util.stanza";
local jid_prep = require"util.jid".prep;
local xmlns_mam = "urn:xmpp:mam:2";

local default_attrs = {
	always = true, [true] = "always",
	never = false, [false] = "never",
	roster = "roster",
}

local function tostanza(prefs)
	local default = prefs[false];
	default = default_attrs[default];
	local prefstanza = st.stanza("prefs", { xmlns = xmlns_mam, default = default });
	local always = st.stanza("always");
	local never = st.stanza("never");
	for jid, choice in pairs(prefs) do
		if jid then
			(choice and always or never):tag("jid"):text(jid):up();
		end
	end
	prefstanza:add_child(always):add_child(never);
	return prefstanza;
end
local function fromstanza(prefstanza)
	local prefs = {};
	local default = prefstanza.attr.default;
	if default then
		prefs[false] = default_attrs[default];
	end

	local always = prefstanza:get_child("always");
	if always then
		for rule in always:childtags("jid") do
			local jid = jid_prep(rule:get_text());
			if jid then
				prefs[jid] = true;
			end
		end
	end

	local never = prefstanza:get_child("never");
	if never then
		for rule in never:childtags("jid") do
			local jid = jid_prep(rule:get_text());
			if jid then
				prefs[jid] = false;
			end
		end
	end

	return prefs;
end

return {
	tostanza = tostanza;
	fromstanza = fromstanza;
}