aboutsummaryrefslogtreecommitdiffstats
path: root/plugins/mod_saslauth.lua
blob: ccdfde76b5f5d17c2e6aec3540e6317a9a0c21a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
-- 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 st = require "util.stanza";
local sm_bind_resource = require "core.sessionmanager".bind_resource;
local sm_make_authenticated = require "core.sessionmanager".make_authenticated;
local base64 = require "util.encodings".base64;

local nodeprep = require "util.encodings".stringprep.nodeprep;
local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler;
local usermanager_user_exists = require "core.usermanager".user_exists;
local t_concat, t_insert = table.concat, table.insert;
local tostring = tostring;

local secure_auth_only = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");
local sasl_backend = module:get_option("sasl_backend") or "builtin";
local anonymous_login = module:get_option("anonymous_login");
local allow_unencrypted_plain_auth = module:get_option("allow_unencrypted_plain_auth")

-- Cyrus config options
local require_provisioning = module:get_option("cyrus_require_provisioning") or false;

local log = module._log;

local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';
local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';
local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';

local new_sasl = require "util.sasl".new;
if sasl_backend ~= "builtin" then
	module:log("error", "Unknown SASL backend: %s", sasl_backend);
	error("Unknown SASL backend");
end

local anonymous_authentication_profile = {
	anonymous = function(username, realm)
		return true; -- for normal usage you should always return true here
	end
};

local function build_reply(status, ret, err_msg)
	local reply = st.stanza(status, {xmlns = xmlns_sasl});
	if status == "challenge" then
		--log("debug", "CHALLENGE: %s", ret or "");
		reply:text(base64.encode(ret or ""));
	elseif status == "failure" then
		reply:tag(ret):up();
		if err_msg then reply:tag("text"):text(err_msg); end
	elseif status == "success" then
		--log("debug", "SUCCESS: %s", ret or "");
		reply:text(base64.encode(ret or ""));
	else
		module:log("error", "Unknown sasl status: %s", status);
	end
	return reply;
end

local function handle_status(session, status, ret, err_msg)
	if status == "failure" then
		session.sasl_handler = session.sasl_handler:clean_clone();
	elseif status == "success" then
		local username = nodeprep(session.sasl_handler.username);

		if not(require_provisioning) or usermanager_user_exists(username, session.host) then
			local ok, err = sm_make_authenticated(session, session.sasl_handler.username);
			if ok then
				session.sasl_handler = nil;
				session:reset_stream();
			else
				module:log("warn", "SASL succeeded but username was invalid");
				session.sasl_handler = session.sasl_handler:clean_clone();
				return "failure", "not-authorized", "User authenticated successfully, but username was invalid";
			end
		else
			module:log("warn", "SASL succeeded but we don't have an account provisioned for %s", username);
			session.sasl_handler = session.sasl_handler:clean_clone();
			return "failure", "not-authorized", "User authenticated successfully, but not provisioned for XMPP";
		end
	end
	return status, ret, err_msg;
end

local function sasl_handler(session, stanza)
	if stanza.name == "auth" then
		-- FIXME ignoring duplicates because ejabberd does
		local mechanism = stanza.attr.mechanism;
		if anonymous_login then
			if mechanism ~= "ANONYMOUS" then
				return session.send(build_reply("failure", "invalid-mechanism"));
			end
		elseif mechanism == "ANONYMOUS" then
			return session.send(build_reply("failure", "mechanism-too-weak"));
		end
		if not session.secure and (secure_auth_only or (mechanism == "PLAIN" and not allow_unencrypted_plain_auth)) then
			return session.send(build_reply("failure", "encryption-required"));
		end
		local valid_mechanism = session.sasl_handler:select(mechanism);
		if not valid_mechanism then
			return session.send(build_reply("failure", "invalid-mechanism"));
		end
	elseif not session.sasl_handler then
		return; -- FIXME ignoring out of order stanzas because ejabberd does
	end
	local text = stanza[1];
	if text then
		text = base64.decode(text);
		--log("debug", "AUTH: %s", text:gsub("[%z\001-\008\011\012\014-\031]", " "));
		if not text then
			session.sasl_handler = nil;
			session.send(build_reply("failure", "incorrect-encoding"));
			return;
		end
	end
	local status, ret, err_msg = session.sasl_handler:process(text);
	status, ret, err_msg = handle_status(session, status, ret, err_msg);
	local s = build_reply(status, ret, err_msg);
	log("debug", "sasl reply: %s", tostring(s));
	session.send(s);
end

module:add_handler("c2s_unauthed", "auth", xmlns_sasl, sasl_handler);
module:add_handler("c2s_unauthed", "abort", xmlns_sasl, sasl_handler);
module:add_handler("c2s_unauthed", "response", xmlns_sasl, sasl_handler);

local mechanisms_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-sasl' };
local bind_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-bind' };
local xmpp_session_attr = { xmlns='urn:ietf:params:xml:ns:xmpp-session' };
module:hook("stream-features", function(event)
	local origin, features = event.origin, event.features;
	if not origin.username then
		if secure_auth_only and not origin.secure then
			return;
		end
		if anonymous_login then
			origin.sasl_handler = new_sasl(module.host, anonymous_authentication_profile);
		else
			origin.sasl_handler = usermanager_get_sasl_handler(module.host);
		end
		features:tag("mechanisms", mechanisms_attr);
		for mechanism in pairs(origin.sasl_handler:mechanisms()) do
			if mechanism ~= "PLAIN" or origin.secure or allow_unencrypted_plain_auth then
				features:tag("mechanism"):text(mechanism):up();
			end
		end
		features:up();
	else
		features:tag("bind", bind_attr):tag("required"):up():up();
		features:tag("session", xmpp_session_attr):tag("optional"):up():up();
	end
end);

module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind", function(session, stanza)
	log("debug", "Client requesting a resource bind");
	local resource;
	if stanza.attr.type == "set" then
		local bind = stanza.tags[1];
		if bind and bind.attr.xmlns == xmlns_bind then
			resource = bind:child_with_name("resource");
			if resource then
				resource = resource[1];
			end
		end
	end
	local success, err_type, err, err_msg = sm_bind_resource(session, resource);
	if not success then
		session.send(st.error_reply(stanza, err_type, err, err_msg));
	else
		session.send(st.reply(stanza)
			:tag("bind", { xmlns = xmlns_bind})
			:tag("jid"):text(session.full_jid));
	end
end);

module:add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session", function(session, stanza)
	log("debug", "Client requesting a session");
	session.send(st.reply(stanza));
end);