view mod_sasl2/mod_sasl2.lua @ 4976:75b6e5df65f9

various: Improve error reporting if missing file server module on 0.12 If there is some error loading net.http.files then it would be swallowed by the pcall and then it would proceed to trying mod_http_files, which might cause unexpected behavior on 0.12 Ref #1765
author Kim Alvefur <zash@zash.se>
date Mon, 18 Jul 2022 22:47:54 +0200
parents 9c7635911c56
children ed2a9a4c4f01
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-- Prosody IM
-- Copyright (C) 2019 Kim Alvefur
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
-- XEP-0388: Extensible SASL Profile
--

local st = require "util.stanza";
local errors = require "util.error";
local base64 = require "util.encodings".base64;
local jid_join = require "util.jid".join;

local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler;
local sm_make_authenticated = require "core.sessionmanager".make_authenticated;

local xmlns_sasl2 = "urn:xmpp:sasl:1";

local allow_unencrypted_plain_auth = module:get_option_boolean("allow_unencrypted_plain_auth", false)
local insecure_mechanisms = module:get_option_set("insecure_sasl_mechanisms", allow_unencrypted_plain_auth and {} or {"PLAIN", "LOGIN"});
local disabled_mechanisms = module:get_option_set("disable_sasl_mechanisms", { "DIGEST-MD5" });

local host = module.host;

module:hook("stream-features", function(event)
	local origin, features = event.origin, event.features;
	local log = origin.log or module._log;

	if origin.type ~= "c2s_unauthed" then
		log("debug", "Already authenticated");
		return
	end

	local sasl_handler = usermanager_get_sasl_handler(host, origin)
	origin.sasl_handler = sasl_handler;

	if sasl_handler.add_cb_handler then -- luacheck: ignore 542
		-- FIXME bring back channel binding
	end

	local mechanisms = st.stanza("mechanisms", { xmlns = xmlns_sasl2 });

	local available_mechanisms = sasl_handler:mechanisms()
	for mechanism in pairs(available_mechanisms) do
		if disabled_mechanisms:contains(mechanism) then
			log("debug", "Not offering disabled mechanism %s", mechanism);
		elseif not origin.secure and insecure_mechanisms:contains(mechanism) then
			log("debug", "Not offering mechanism %s on insecure connection", mechanism);
		else
			log("debug", "Offering mechanism %s", mechanism);
			mechanisms:text_tag("mechanism", mechanism);
		end
	end

	features:add_direct_child(mechanisms);
end, 1);

local function handle_status(session, status, ret, err_msg)
	local err = nil;
	if status == "error" then
		ret, err = nil, ret;
		if not errors.is_err(err) then
			err = errors.new({ condition = err, text = err_msg }, { session = session });
		end
	end

	module:fire_event("sasl2/"..session.base_type.."/"..status, {
			session = session,
			message = ret;
			error = err;
		});
end

module:hook("sasl2/c2s/failure", function (event)
	local session = event.session
	session.send(st.stanza("failure", { xmlns = xmlns_sasl2 })
		:tag(event.error.condition));
	return true;
end);

module:hook("sasl2/c2s/challenge", function (event)
	local session = event.session;
	session.send(st.stanza("challenge", { xmlns = xmlns_sasl2 })
		:text_tag(event.message));
end);

module:hook("sasl2/c2s/success", function (event)
	local session = event.session
	local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
	if not ok then
		handle_status(session, "failure", err);
		return true;
	end
	event.success = st.stanza("success", { xmlns = xmlns_sasl2 });
end, 1000);

module:hook("sasl2/c2s/success", function (event)
	local session = event.session
	event.success:text_tag("authorization-identifier", jid_join(session.username, session.host, session.resource));
	session.send(event.success);
	local features = st.stanza("stream:features");
	module:fire_event("stream-features", { origin = session, features = features });
	session.send(features);
end, -1000);

local function process_cdata(session, cdata)
	if cdata then
		cdata = base64.decode(cdata);
		if not cdata then
			return handle_status(session, "failure");
		end
	end
	return handle_status(session, session.sasl_handler:process(cdata));
end

module:hook_tag(xmlns_sasl2, "authenticate", function (session, auth)
	local sasl_handler = session.sasl_handler;
	if not sasl_handler then
		sasl_handler = usermanager_get_sasl_handler(host, session);
		session.sasl_handler = sasl_handler;
	end
	local mechanism = assert(auth.attr.mechanism);
	if not sasl_handler:select(mechanism) then
		return handle_status(session, "failure");
	end
	local initial = auth:get_child_text("initial-response");
	return process_cdata(session, initial);
end);

module:hook_tag(xmlns_sasl2, "response", function (session, response)
	local sasl_handler = session.sasl_handler;
	if not sasl_handler or not sasl_handler.selected then
		return handle_status(session, "failure");
	end
	return process_cdata(session, response:get_text());
end);