Software / code / prosody
File
plugins/muc/moderated.lib.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 | 9035:173c0e16e704 |
line wrap: on
line source
-- 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 function get_moderated(room) return room._data.moderated; end local function set_moderated(room, moderated) moderated = moderated and true or nil; if get_moderated(room) == moderated then return false; end room._data.moderated = moderated; return true; end module:hook("muc-disco#info", function(event) event.reply:tag("feature", {var = get_moderated(event.room) and "muc_moderated" or "muc_unmoderated"}):up(); end); module:hook("muc-config-form", function(event) table.insert(event.form, { name = "muc#roomconfig_moderatedroom"; type = "boolean"; label = "Moderated (require permission to speak)"; desc = "In moderated rooms occupants must be given permission to speak by a room moderator"; value = get_moderated(event.room); }); end, 80-3); module:hook("muc-config-submitted/muc#roomconfig_moderatedroom", function(event) if set_moderated(event.room, event.value) then event.status_codes["104"] = true; end end); module:hook("muc-get-default-role", function(event) if event.affiliation == nil then if get_moderated(event.room) then -- XEP-0045: -- An implementation MAY grant voice by default to visitors in unmoderated rooms. return "visitor" end end end, 1); return { get = get_moderated; set = set_moderated; };