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prosody
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plugins/muc/persistent.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 | 9053:ea9e1f8f3013 |
child | 12642:9061f9621330 |
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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 restrict_persistent = not module:get_option_boolean("muc_room_allow_persistent", true); local um_is_admin = require "core.usermanager".is_admin; local function get_persistent(room) return room._data.persistent; end local function set_persistent(room, persistent) persistent = persistent and true or nil; if get_persistent(room) == persistent then return false; end room._data.persistent = persistent; return true; end module:hook("muc-config-form", function(event) if restrict_persistent and not um_is_admin(event.actor, module.host) then -- Don't show option if hidden rooms are restricted and user is not admin of this host return; end table.insert(event.form, { name = "muc#roomconfig_persistentroom"; type = "boolean"; label = "Persistent (room should remain even when it is empty)"; desc = "Rooms are automatically deleted when they are empty, unless this option is enabled"; value = get_persistent(event.room); }); end, 100-5); module:hook("muc-config-submitted/muc#roomconfig_persistentroom", function(event) if restrict_persistent and not um_is_admin(event.actor, module.host) then return; -- Not allowed end if set_persistent(event.room, event.value) then event.status_codes["104"] = true; end end); module:hook("muc-disco#info", function(event) event.reply:tag("feature", {var = get_persistent(event.room) and "muc_persistent" or "muc_temporary"}):up(); end); module:hook("muc-room-destroyed", function(event) set_persistent(event.room, false); end, -100); return { get = get_persistent; set = set_persistent; };