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plugins/muc/lock.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 | 8866:2c60ae791bdc |
child | 10450:c1edeb9fe337 |
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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 st = require "util.stanza"; local lock_rooms = module:get_option_boolean("muc_room_locking", true); local lock_room_timeout = module:get_option_number("muc_room_lock_timeout", 300); local function lock(room) module:fire_event("muc-room-locked", {room = room;}); room._data.locked = os.time() + lock_room_timeout; end local function unlock(room) module:fire_event("muc-room-unlocked", {room = room;}); room._data.locked = nil; end local function is_locked(room) local ts = room._data.locked; if ts then if os.time() < ts then return true; end unlock(room); end return false; end if lock_rooms then module:hook("muc-room-pre-create", function(event) -- Older groupchat protocol doesn't lock if not event.stanza:get_child("x", "http://jabber.org/protocol/muc") then return end -- Lock room at creation local room = event.room; lock(room); end, 10); end -- Don't let users into room while it is locked module:hook("muc-occupant-pre-join", function(event) if not event.is_new_room and is_locked(event.room) then -- Deny entry module:log("debug", "Room is locked, denying entry"); event.origin.send(st.error_reply(event.stanza, "cancel", "item-not-found")); return true; end end, -30); -- When config is submitted; unlock the room module:hook("muc-config-submitted", function(event) if is_locked(event.room) then unlock(event.room); end end, -1); return { lock = lock; unlock = unlock; is_locked = is_locked; };