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core/s2smanager.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 | 8675:d3d74e923e4e |
child | 9787:6625efab91e2 |
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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 hosts = prosody.hosts; local tostring, pairs, setmetatable = tostring, pairs, setmetatable; local logger_init = require "util.logger".init; local log = logger_init("s2smanager"); local prosody = _G.prosody; local incoming_s2s = {}; _G.incoming_s2s = incoming_s2s; prosody.incoming_s2s = incoming_s2s; local fire_event = prosody.events.fire_event; local _ENV = nil; -- luacheck: std none local function new_incoming(conn) local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming", hosts = {} }; session.log = logger_init("s2sin"..tostring(session):match("[a-f0-9]+$")); incoming_s2s[session] = true; return session; end local function new_outgoing(from_host, to_host) local host_session = { to_host = to_host, from_host = from_host, host = from_host, notopen = true, type = "s2sout_unauthed", direction = "outgoing" }; hosts[from_host].s2sout[to_host] = host_session; local conn_name = "s2sout"..tostring(host_session):match("[a-f0-9]*$"); host_session.log = logger_init(conn_name); return host_session; end local resting_session = { -- Resting, not dead destroyed = true; type = "s2s_destroyed"; open_stream = function (session) session.log("debug", "Attempt to open stream on resting session"); end; close = function (session) session.log("debug", "Attempt to close already-closed session"); end; filter = function (type, data) return data; end; --luacheck: ignore 212/type }; resting_session.__index = resting_session; local function retire_session(session, reason) local log = session.log or log; --luacheck: ignore 431/log for k in pairs(session) do if k ~= "log" and k ~= "id" and k ~= "conn" then session[k] = nil; end end session.destruction_reason = reason; function session.send(data) log("debug", "Discarding data sent to resting session: %s", tostring(data)); end function session.data(data) log("debug", "Discarding data received from resting session: %s", tostring(data)); end session.thread = { run = function (_, data) return session.data(data) end }; session.sends2s = session.send; return setmetatable(session, resting_session); end local function destroy_session(session, reason) if session.destroyed then return; end (session.log or log)("debug", "Destroying "..tostring(session.direction) .." session "..tostring(session.from_host).."->"..tostring(session.to_host) ..(reason and (": "..reason) or "")); if session.direction == "outgoing" then hosts[session.from_host].s2sout[session.to_host] = nil; session:bounce_sendq(reason); elseif session.direction == "incoming" then incoming_s2s[session] = nil; end local event_data = { session = session, reason = reason }; if session.type == "s2sout" then fire_event("s2sout-destroyed", event_data); if hosts[session.from_host] then hosts[session.from_host].events.fire_event("s2sout-destroyed", event_data); end elseif session.type == "s2sin" then fire_event("s2sin-destroyed", event_data); if hosts[session.to_host] then hosts[session.to_host].events.fire_event("s2sin-destroyed", event_data); end end retire_session(session, reason); -- Clean session until it is GC'd return true; end return { incoming_s2s = incoming_s2s; new_incoming = new_incoming; new_outgoing = new_outgoing; retire_session = retire_session; destroy_session = destroy_session; };