File

plugins/mod_legacyauth.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 10557:e1cb869e2f6c
child 12328:a80314101bc6
line wrap: on
line source

-- 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 = require "util.stanza";
local t_concat = table.concat;

local secure_auth_only = module:get_option("c2s_require_encryption",
	module:get_option("require_encryption"))
	or not(module:get_option("allow_unencrypted_plain_auth"));

local sessionmanager = require "core.sessionmanager";
local usermanager = require "core.usermanager";
local nodeprep = require "util.encodings".stringprep.nodeprep;
local resourceprep = require "util.encodings".stringprep.resourceprep;

module:add_feature("jabber:iq:auth");
module:hook("stream-features", function(event)
	local origin, features = event.origin, event.features;
	if secure_auth_only and not origin.secure then
		-- Sorry, not offering to insecure streams!
		return;
	elseif not origin.username then
		features:tag("auth", {xmlns='http://jabber.org/features/iq-auth'}):up();
	end
end);

module:hook("stanza/iq/jabber:iq:auth:query", function(event)
	local session, stanza = event.origin, event.stanza;

	if session.type ~= "c2s_unauthed" then
		(session.sends2s or session.send)(st.error_reply(stanza, "cancel", "service-unavailable",
			"Legacy authentication is only allowed for unauthenticated client connections."));
		return true;
	end

	if secure_auth_only and not session.secure then
		session.send(st.error_reply(stanza, "modify", "not-acceptable", "Encryption (SSL or TLS) is required to connect to this server"));
		return true;
	end

	local query = stanza.tags[1];
	local username = query:get_child("username");
	local password = query:get_child("password");
	local resource = query:get_child("resource");
	if not (username and password and resource) then
		local reply = st.reply(stanza);
		session.send(reply:query("jabber:iq:auth")
			:tag("username"):up()
			:tag("password"):up()
			:tag("resource"):up());
	else
		username, password, resource = t_concat(username), t_concat(password), t_concat(resource);
		username = nodeprep(username);
		resource = resourceprep(resource)
		if not (username and resource) then
			session.send(st.error_reply(stanza, "modify", "bad-request"));
			return true;
		end
		if usermanager.test_password(username, session.host, password) then
			-- Authentication successful!
			local success, err = sessionmanager.make_authenticated(session, username);
			if success then
				local err_type, err_msg;
				success, err_type, err, err_msg = sessionmanager.bind_resource(session, resource);
				if not success then
					session.send(st.error_reply(stanza, err_type, err, err_msg));
					session.username, session.type = nil, "c2s_unauthed"; -- FIXME should this be placed in sessionmanager?
					return true;
				elseif resource ~= session.resource then -- server changed resource, not supported by legacy auth
					session.send(st.error_reply(stanza, "cancel", "conflict", "The requested resource could not be assigned to this session."));
					session:close(); -- FIXME undo resource bind and auth instead of closing the session?
					return true;
				end
				session.send(st.reply(stanza));
			else
				session.send(st.error_reply(stanza, "auth", "not-authorized", err));
			end
		else
			session.send(st.error_reply(stanza, "auth", "not-authorized"));
		end
	end
	return true;
end);