Software /
code /
prosody
File
plugins/mod_auth_cyrus.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 | 8054:0ba461b7d9af |
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. -- -- luacheck: ignore 212 local log = require "util.logger".init("auth_cyrus"); local usermanager_user_exists = require "core.usermanager".user_exists; local cyrus_service_realm = module:get_option("cyrus_service_realm"); local cyrus_service_name = module:get_option("cyrus_service_name"); local cyrus_application_name = module:get_option("cyrus_application_name"); local require_provisioning = module:get_option("cyrus_require_provisioning") or false; local host_fqdn = module:get_option("cyrus_server_fqdn"); prosody.unlock_globals(); --FIXME: Figure out why this is needed and -- why cyrussasl isn't caught by the sandbox local cyrus_new = require "util.sasl_cyrus".new; prosody.lock_globals(); local new_sasl = function(realm) return cyrus_new( cyrus_service_realm or realm, cyrus_service_name or "xmpp", cyrus_application_name or "prosody", host_fqdn ); end do -- diagnostic local list; for mechanism in pairs(new_sasl(module.host):mechanisms()) do list = (not(list) and mechanism) or (list..", "..mechanism); end if not list then module:log("error", "No Cyrus SASL mechanisms available"); else module:log("debug", "Available Cyrus SASL mechanisms: %s", list); end end local host = module.host; -- define auth provider local provider = {}; log("debug", "initializing default authentication provider for host '%s'", host); function provider.test_password(username, password) return nil, "Legacy auth not supported with Cyrus SASL."; end function provider.get_password(username) return nil, "Passwords unavailable for Cyrus SASL."; end function provider.set_password(username, password) return nil, "Passwords unavailable for Cyrus SASL."; end function provider.user_exists(username) if require_provisioning then return usermanager_user_exists(username, host); end return true; end function provider.create_user(username, password) return nil, "Account creation/modification not available with Cyrus SASL."; end function provider.get_sasl_handler() local handler = new_sasl(host); if require_provisioning then function handler.require_provisioning(username) return usermanager_user_exists(username, host); end end return handler; end module:provides("auth", provider);