File

plugins/muc/util.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 9603:4897bd63f624
child 10713:38159b9adf9f
line wrap: on
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
-- Copyright (C) 2014 Daurnimator
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local _M = {};

_M.valid_affiliations = {
	outcast = -1;
	none = 0;
	member = 1;
	admin = 2;
	owner = 3;
};

_M.valid_roles = {
	none = 0;
	visitor = 1;
	participant = 2;
	moderator = 3;
};

local kickable_error_conditions = {
	["gone"] = true;
	["internal-server-error"] = true;
	["item-not-found"] = true;
	["jid-malformed"] = true;
	["recipient-unavailable"] = true;
	["redirect"] = true;
	["remote-server-not-found"] = true;
	["remote-server-timeout"] = true;
	["service-unavailable"] = true;
	["malformed error"] = true;
};
function _M.is_kickable_error(stanza)
	local cond = select(2, stanza:get_error()) or "malformed error";
	return kickable_error_conditions[cond];
end

local muc_x_filters = {
	["http://jabber.org/protocol/muc"] = true;
	["http://jabber.org/protocol/muc#user"] = true;
}
local function muc_x_filter(tag)
	if muc_x_filters[tag.attr.xmlns] then
		return nil;
	end
	return tag;
end
function _M.filter_muc_x(stanza)
	return stanza:maptags(muc_x_filter);
end

function _M.only_with_min_role(role)
	local min_role_value = _M.valid_roles[role];
	return function (nick, occupant) --luacheck: ignore 212/nick
		if _M.valid_roles[occupant.role or "none"] >= min_role_value then
			return true;
		end
	end;
end

return _M;