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plugins/mod_mam/mamprefsxml.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> |
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date | Mon, 10 Jan 2022 18:23:54 +0100 |
parent | 9728:d41ce505cdf9 |
child | 12977:74b9e05af71e |
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-- Prosody IM -- Copyright (C) 2008-2017 Matthew Wild -- Copyright (C) 2008-2017 Waqas Hussain -- Copyright (C) 2011-2017 Kim Alvefur -- Copyright (C) 2018 Emmanuel Gil Peyrot -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- -- XEP-0313: Message Archive Management for Prosody -- local st = require"util.stanza"; local jid_prep = require"util.jid".prep; local xmlns_mam = "urn:xmpp:mam:2"; local default_attrs = { always = true, [true] = "always", never = false, [false] = "never", roster = "roster", } local function tostanza(prefs) local default = prefs[false]; default = default_attrs[default]; local prefstanza = st.stanza("prefs", { xmlns = xmlns_mam, default = default }); local always = st.stanza("always"); local never = st.stanza("never"); for jid, choice in pairs(prefs) do if jid then (choice and always or never):tag("jid"):text(jid):up(); end end prefstanza:add_child(always):add_child(never); return prefstanza; end local function fromstanza(prefstanza) local prefs = {}; local default = prefstanza.attr.default; if default then prefs[false] = default_attrs[default]; end local always = prefstanza:get_child("always"); if always then for rule in always:childtags("jid") do local jid = jid_prep(rule:get_text()); if jid then prefs[jid] = true; end end end local never = prefstanza:get_child("never"); if never then for rule in never:childtags("jid") do local jid = jid_prep(rule:get_text()); if jid then prefs[jid] = false; end end end return prefs; end return { tostanza = tostanza; fromstanza = fromstanza; }