plugins/mod_dialback.lua

-- 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 = _G.hosts;

local send_s2s = require "core.s2smanager".send_to_host;

local s2s_make_authenticated = require "core.s2smanager".make_authenticated;

local s2s_initiate_dialback = require "core.s2smanager".initiate_dialback;

local s2s_verify_dialback = require "core.s2smanager".verify_dialback;

local s2s_destroy_session = require "core.s2smanager".destroy_session;

local log = module._log;

local st = require "util.stanza";

local xmlns_stream = "http://etherx.jabber.org/streams";

local xmlns_dialback = "jabber:server:dialback";

local dialback_requests = setmetatable({}, { __mode = 'v' });

module:hook("stanza/jabber:server:dialback:verify", function(event)

	local origin, stanza = event.origin, event.stanza;

	if origin.type == "s2sin_unauthed" or origin.type == "s2sin" then

		-- We are being asked to verify the key, to ensure it was generated by us

		origin.log("debug", "verifying that dialback key is ours...");

		local attr = stanza.attr;

		-- COMPAT: Grr, ejabberd breaks this one too?? it is black and white in XEP-220 example 34

		--if attr.from ~= origin.to_host then error("invalid-from"); end

		local type;

		if s2s_verify_dialback(attr.id, attr.from, attr.to, stanza:get_text()) then

			type = "valid"

		else

			type = "invalid"

			origin.log("warn", "Asked to verify a dialback key that was incorrect. An imposter is claiming to be %s?", attr.to);

		end

		origin.log("debug", "verified dialback key... it is %s", type);

		origin.sends2s(st.stanza("db:verify", { from = attr.to, to = attr.from, id = attr.id, type = type }):text(stanza:get_text()));

		return true;

	end

end);

module:hook("stanza/jabber:server:dialback:result", function(event)

	local origin, stanza = event.origin, event.stanza;

	if origin.type == "s2sin_unauthed" or origin.type == "s2sin" then

		-- he wants to be identified through dialback

		-- We need to check the key with the Authoritative server

		local attr = stanza.attr;

		origin.hosts[attr.from] = { dialback_key = stanza:get_text() };

		if not hosts[attr.to] then

			-- Not a host that we serve

			origin.log("info", "%s tried to connect to %s, which we don't serve", attr.from, attr.to);

			origin:close("host-unknown");

			return true;

		end

		dialback_requests[attr.from] = origin;

		if not origin.from_host then

			-- Just used for friendlier logging

			origin.from_host = attr.from;

		end

		if not origin.to_host then

			-- Just used for friendlier logging

			origin.to_host = attr.to;

		end

		origin.log("debug", "asking %s if key %s belongs to them", attr.from, stanza:get_text());

		send_s2s(attr.to, attr.from,

			st.stanza("db:verify", { from = attr.to, to = attr.from, id = origin.streamid }):text(stanza:get_text()));

		return true;

	end

end);

module:hook("stanza/jabber:server:dialback:verify", function(event)

	local origin, stanza = event.origin, event.stanza;

	if origin.type == "s2sout_unauthed" or origin.type == "s2sout" then

		local attr = stanza.attr;

		local dialback_verifying = dialback_requests[attr.from];

		if dialback_verifying then

			local valid;

			if attr.type == "valid" then

				s2s_make_authenticated(dialback_verifying, attr.from);

				valid = "valid";

			else

				-- Warn the original connection that is was not verified successfully

				log("warn", "authoritative server for "..(attr.from or "(unknown)").." denied the key");

				valid = "invalid";

			end

			if not dialback_verifying.sends2s then

				log("warn", "Incoming s2s session %s was closed in the meantime, so we can't notify it of the db result", tostring(dialback_verifying):match("%w+$"));

			else

				dialback_verifying.sends2s(

						st.stanza("db:result", { from = attr.to, to = attr.from, id = attr.id, type = valid })

								:text(dialback_verifying.hosts[attr.from].dialback_key));

			end

			dialback_requests[attr.from] = nil;

		end

		return true;

	end

end);

module:hook("stanza/jabber:server:dialback:result", function(event)

	local origin, stanza = event.origin, event.stanza;

	if origin.type == "s2sout_unauthed" or origin.type == "s2sout" then

		-- Remote server is telling us whether we passed dialback

		local attr = stanza.attr;

		if not hosts[attr.to] then

			origin:close("host-unknown");

			return true;

		elseif hosts[attr.to].s2sout[attr.from] ~= origin then

			-- This isn't right

			origin:close("invalid-id");

			return true;

		end

		if stanza.attr.type == "valid" then

			s2s_make_authenticated(origin, attr.from);

		else

			s2s_destroy_session(origin)

		end

		return true;

	end

end);

module:hook_stanza("urn:ietf:params:xml:ns:xmpp-sasl", "failure", function (origin, stanza)

	if origin.external_auth == "failed" then

		module:log("debug", "SASL EXTERNAL failed, falling back to dialback");

		s2s_initiate_dialback(origin);

		return true;

	end

end, 100);

module:hook_stanza(xmlns_stream, "features", function (origin, stanza)

	if not origin.external_auth or origin.external_auth == "failed" then

		s2s_initiate_dialback(origin);

		return true;

	end

end, 100);

-- Offer dialback to incoming hosts

module:hook("s2s-stream-features", function (data)

	data.features:tag("dialback", { xmlns='urn:xmpp:features:dialback' }):tag("optional"):up():up();

end);