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plugins/mod_version.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 | 9436:a950f9fa9137 |
child | 12977:74b9e05af71e |
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-- 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. -- local st = require "util.stanza"; module:add_feature("jabber:iq:version"); local query = st.stanza("query", {xmlns = "jabber:iq:version"}) :text_tag("name", "Prosody") :text_tag("version", prosody.version); if not module:get_option_boolean("hide_os_type") then local platform; if os.getenv("WINDIR") then platform = "Windows"; else local os_version_command = module:get_option_string("os_version_command"); local ok, pposix = pcall(require, "util.pposix"); if not os_version_command and (ok and pposix and pposix.uname) then platform = pposix.uname().sysname; end if not platform then local uname = io.popen(os_version_command or "uname"); if uname then platform = uname:read("*a"); end uname:close(); end end if platform then platform = platform:match("^%s*(.-)%s*$") or platform; query:text_tag("os", platform); end end module:hook("iq-get/host/jabber:iq:version:query", function(event) local origin, stanza = event.origin, event.stanza; origin.send(st.reply(stanza):add_child(query)); return true; end);