File

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
line wrap: on
line source

-- 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;
};