2 -- Copyright (C) 2008-2009 Tobias Markmann
4 -- All rights reserved.
6 -- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
8 -- * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
9 -- * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
10 -- * Neither the name of Tobias Markmann nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
12 -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
15 local md5 = require "util.hashes".md5;
16 local log = require "util.logger".init("sasl");
17 local tostring = tostring;
18 local st = require "util.stanza";
19 local generate_uuid = require "util.uuid".generate;
20 local t_insert, t_concat = table.insert, table.concat;
21 local to_byte, to_char = string.byte, string.char;
22 local s_match = string.match;
23 local gmatch = string.gmatch
25 local math = require "math"
32 local function new_plain(realm, password_handler)
33 local object = { mechanism = "PLAIN", realm = realm, password_handler = password_handler}
34 function object.feed(self, message)
36 if message == "" or message == nil then return "failure", "malformed-request" end
37 local response = message
38 local authorization = s_match(response, "([^&%z]+)")
39 local authentication = s_match(response, "%z([^&%z]+)%z")
40 local password = s_match(response, "%z[^&%z]+%z([^&%z]+)")
42 if authentication == nil or password == nil then return "failure", "malformed-request" end
44 local password_encoding, correct_password = self.password_handler(authentication, self.realm, "PLAIN")
46 if correct_password == nil then return "failure", "not-authorized"
47 elseif correct_password == false then return "failure", "account-disabled" end
49 local claimed_password = ""
50 if password_encoding == nil then claimed_password = password
51 else claimed_password = password_encoding(password) end
53 self.username = authentication
54 if claimed_password == correct_password then
57 return "failure", "not-authorized"
64 -- implementing RFC 2831
65 local function new_digest_md5(realm, password_handler)
66 --TODO complete support for authzid
68 local function serialize(message)
71 if type(message) ~= "table" then error("serialize needs an argument of type table.") end
73 -- testing all possible values
74 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
75 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
76 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
77 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
78 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
79 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
80 data = data:gsub(",$", "")
84 local function utf8tolatin1ifpossible(passwd)
87 local passwd_i = to_byte(passwd:sub(i, i));
88 if passwd_i > 0x7F then
89 if passwd_i < 0xC0 or passwd_i > 0xC3 then
93 passwd_i = to_byte(passwd:sub(i, i));
94 if passwd_i < 0x80 or passwd_i > 0xBF then
104 while (i <= #passwd) do
105 local passwd_i = to_byte(passwd:sub(i, i));
106 if passwd_i > 0x7F then
108 local passwd_i_1 = to_byte(passwd:sub(i, i));
109 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
111 t_insert(p, to_char(passwd_i));
117 local function latin1toutf8(str)
119 for ch in gmatch(str, ".") do
122 t_insert(p, to_char(ch));
123 elseif (ch < 0xC0) then
124 t_insert(p, to_char(0xC2, ch));
126 t_insert(p, to_char(0xC3, ch - 64));
131 local function parse(data)
133 for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
139 local object = { mechanism = "DIGEST-MD5", realm = realm, password_handler = password_handler};
141 --TODO: something better than math.random would be nice, maybe OpenSSL's random number generator
142 object.nonce = generate_uuid();
144 object.nonce_count = {};
146 function object.feed(self, message)
147 self.step = self.step + 1;
148 if (self.step == 1) then
149 local challenge = serialize({ nonce = object.nonce,
152 algorithm = "md5-sess",
153 realm = self.realm});
154 return "challenge", challenge;
155 elseif (self.step == 2) then
156 local response = parse(message);
157 -- check for replay attack
158 if response["nc"] then
159 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
162 -- check for username, it's REQUIRED by RFC 2831
163 if not response["username"] then
164 return "failure", "malformed-request";
166 self["username"] = response["username"];
168 -- check for nonce, ...
169 if not response["nonce"] then
170 return "failure", "malformed-request";
172 -- check if it's the right nonce
173 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
176 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
177 if not response["qop"] then response["qop"] = "auth" end
179 if response["realm"] == nil or response["realm"] == "" then
180 response["realm"] = self.realm;
181 elseif response["realm"] ~= self.realm then
182 return "failure", "not-authorized", "Incorrect realm value";
186 if response["charset"] == nil then
187 decoder = utf8tolatin1ifpossible;
188 elseif response["charset"] ~= "utf-8" then
189 return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8.";
194 if response["digest-uri"] then
195 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
196 if protocol == nil or domain == nil then return "failure", "malformed-request" end
198 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
201 --TODO maybe realm support
202 self.username = response["username"];
203 local password_encoding, Y = self.password_handler(response["username"], response["realm"], "DIGEST-MD5", decoder)
204 if Y == nil then return "failure", "not-authorized"
205 elseif Y == false then return "failure", "account-disabled" end
207 if response.authzid then
208 if response.authzid == self.username.."@"..self.realm then
209 log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
210 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
215 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
217 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
219 local HA1 = md5(A1, true);
220 local HA2 = md5(A2, true);
222 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
223 local response_value = md5(KD, true);
225 if response_value == response["response"] then
227 A2 = ":"..protocol.."/"..domain;
232 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
233 local rspauth = md5(KD, true);
234 self.authenticated = true;
235 return "challenge", serialize({rspauth = rspauth});
237 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
239 elseif self.step == 3 then
240 if self.authenticated ~= nil then return "success"
241 else return "failure", "malformed-request" end
247 local function new_anonymous(realm, password_handler)
248 local object = { mechanism = "ANONYMOUS", realm = realm, password_handler = password_handler}
249 function object.feed(self, message)
252 --TODO: From XEP-0175 "It is RECOMMENDED for the node identifier to be a UUID as specified in RFC 4122 [5]." So util.uuid() should (or have an option to) behave as specified in RFC 4122.
253 object["username"] = generate_uuid()
258 function new(mechanism, realm, password_handler)
260 if mechanism == "PLAIN" then object = new_plain(realm, password_handler)
261 elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, password_handler)
262 elseif mechanism == "ANONYMOUS" then object = new_anonymous(realm, password_handler)
264 log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));