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 to_unicode = require "util.encodings".idna.to_unicode;
23 local saslprep = require "util.encodings".stringprep.saslprep;
24 local s_match = string.match;
25 local gmatch = string.gmatch
27 local math = require "math"
34 local function new_plain(realm, password_handler)
35 local object = { mechanism = "PLAIN", realm = realm, password_handler = password_handler}
36 function object.feed(self, message)
38 if message == "" or message == nil then return "failure", "malformed-request" end
39 local response = message
40 local authorization = s_match(response, "([^%z]+)")
41 local authentication = s_match(response, "%z([^%z]+)%z")
42 local password = s_match(response, "%z[^%z]+%z([^%z]+)")
43 authorization, authentication, password = saslprep(authorization), saslprep(authentication), saslprep(password);
45 if authentication == nil or password == nil then return "failure", "malformed-request" end
47 local password_encoding, correct_password = self.password_handler(authentication, self.realm, self.realm, "PLAIN")
49 if correct_password == nil then return "failure", "not-authorized"
50 elseif correct_password == false then return "failure", "account-disabled" end
52 local claimed_password = ""
53 if password_encoding == nil then claimed_password = password
54 else claimed_password = password_encoding(password) end
55 claimed_password = saslprep(claimed_password);
57 self.username = authentication
58 if claimed_password == correct_password then
61 return "failure", "not-authorized"
68 -- implementing RFC 2831
69 local function new_digest_md5(realm, password_handler)
70 --TODO complete support for authzid
72 local function serialize(message)
75 if type(message) ~= "table" then error("serialize needs an argument of type table.") end
77 -- testing all possible values
78 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
79 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
80 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
81 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
82 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
83 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
84 data = data:gsub(",$", "")
88 local function utf8tolatin1ifpossible(passwd)
91 local passwd_i = to_byte(passwd:sub(i, i));
92 if passwd_i > 0x7F then
93 if passwd_i < 0xC0 or passwd_i > 0xC3 then
97 passwd_i = to_byte(passwd:sub(i, i));
98 if passwd_i < 0x80 or passwd_i > 0xBF then
108 while (i <= #passwd) do
109 local passwd_i = to_byte(passwd:sub(i, i));
110 if passwd_i > 0x7F then
112 local passwd_i_1 = to_byte(passwd:sub(i, i));
113 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
115 t_insert(p, to_char(passwd_i));
121 local function latin1toutf8(str)
123 for ch in gmatch(str, ".") do
126 t_insert(p, to_char(ch));
127 elseif (ch < 0xC0) then
128 t_insert(p, to_char(0xC2, ch));
130 t_insert(p, to_char(0xC3, ch - 64));
135 local function parse(data)
137 for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
143 local object = { mechanism = "DIGEST-MD5", realm = realm, password_handler = password_handler};
145 object.nonce = generate_uuid();
147 object.nonce_count = {};
149 function object.feed(self, message)
150 self.step = self.step + 1;
151 if (self.step == 1) then
152 local challenge = serialize({ nonce = object.nonce,
155 algorithm = "md5-sess",
156 realm = self.realm});
157 return "challenge", challenge;
158 elseif (self.step == 2) then
159 local response = parse(message);
160 -- check for replay attack
161 if response["nc"] then
162 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
165 -- check for username, it's REQUIRED by RFC 2831
166 if not response["username"] then
167 return "failure", "malformed-request";
169 self["username"] = response["username"];
171 -- check for nonce, ...
172 if not response["nonce"] then
173 return "failure", "malformed-request";
175 -- check if it's the right nonce
176 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
179 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
180 if not response["qop"] then response["qop"] = "auth" end
182 if response["realm"] == nil or response["realm"] == "" then
183 response["realm"] = "";
184 elseif response["realm"] ~= self.realm then
185 return "failure", "not-authorized", "Incorrect realm value";
189 if response["charset"] == nil then
190 decoder = utf8tolatin1ifpossible;
191 elseif response["charset"] ~= "utf-8" then
192 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.";
197 if response["digest-uri"] then
198 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
199 if protocol == nil or domain == nil then return "failure", "malformed-request" end
201 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
204 --TODO maybe realm support
205 self.username = response["username"];
206 local password_encoding, Y = self.password_handler(response["username"], to_unicode(domain), response["realm"], "DIGEST-MD5", decoder);
207 if Y == nil then return "failure", "not-authorized"
208 elseif Y == false then return "failure", "account-disabled" end
210 if response.authzid then
211 if response.authzid == self.username.."@"..self.realm then
213 log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
214 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
219 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
221 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
223 local HA1 = md5(A1, true);
224 local HA2 = md5(A2, true);
226 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
227 local response_value = md5(KD, true);
229 if response_value == response["response"] then
231 A2 = ":"..protocol.."/"..domain;
236 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
237 local rspauth = md5(KD, true);
238 self.authenticated = true;
239 return "challenge", serialize({rspauth = rspauth});
241 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
243 elseif self.step == 3 then
244 if self.authenticated ~= nil then return "success"
245 else return "failure", "malformed-request" end
251 local function new_anonymous(realm, password_handler)
252 local object = { mechanism = "ANONYMOUS", realm = realm, password_handler = password_handler}
253 function object.feed(self, message)
256 object["username"] = generate_uuid()
261 function new(mechanism, realm, password_handler)
263 if mechanism == "PLAIN" then object = new_plain(realm, password_handler)
264 elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, password_handler)
265 elseif mechanism == "ANONYMOUS" then object = new_anonymous(realm, password_handler)
267 log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));