Software /
code /
prosody
File
util/random.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 | 10016:af8c514e5cf7 |
child | 12446:e54b8a5e35ad |
line wrap: on
line source
-- Prosody IM -- Copyright (C) 2008-2014 Matthew Wild -- Copyright (C) 2008-2014 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local ok, crand = pcall(require, "util.crand"); if ok then return crand; end local urandom, urandom_err = io.open("/dev/urandom", "r"); local function bytes(n) local data, err = urandom:read(n); if not data then if err then error("Unable to retrieve data from secure random number generator (/dev/urandom): "..tostring(err)); else error("Secure random number generator (/dev/urandom) returned an end-of-file condition"); end end return data; end if not urandom then function bytes() error("Unable to obtain a secure random number generator, please see https://prosody.im/doc/random ("..urandom_err..")"); end end return { bytes = bytes; _source = "/dev/urandom"; };