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 s_match = string.match;
24 local gmatch = string.gmatch
26 local math = require "math"
33 local function new_plain(realm, password_handler)
34 local object = { mechanism = "PLAIN", realm = realm, password_handler = password_handler}
35 function object.feed(self, message)
37 if message == "" or message == nil then return "failure", "malformed-request" end
38 local response = message
39 local authorization = s_match(response, "([^&%z]+)")
40 local authentication = s_match(response, "%z([^&%z]+)%z")
41 local password = s_match(response, "%z[^&%z]+%z([^&%z]+)")
43 if authentication == nil or password == nil then return "failure", "malformed-request" end
45 local password_encoding, correct_password = self.password_handler(authentication, self.realm, self.realm, "PLAIN")
47 if correct_password == nil then return "failure", "not-authorized"
48 elseif correct_password == false then return "failure", "account-disabled" end
50 local claimed_password = ""
51 if password_encoding == nil then claimed_password = password
52 else claimed_password = password_encoding(password) end
54 self.username = authentication
55 if claimed_password == correct_password then
58 return "failure", "not-authorized"
65 -- implementing RFC 2831
66 local function new_digest_md5(realm, password_handler)
67 --TODO complete support for authzid
69 local function serialize(message)
72 if type(message) ~= "table" then error("serialize needs an argument of type table.") end
74 -- testing all possible values
75 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
76 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
77 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
78 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
79 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
80 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
81 data = data:gsub(",$", "")
85 local function utf8tolatin1ifpossible(passwd)
88 local passwd_i = to_byte(passwd:sub(i, i));
89 if passwd_i > 0x7F then
90 if passwd_i < 0xC0 or passwd_i > 0xC3 then
94 passwd_i = to_byte(passwd:sub(i, i));
95 if passwd_i < 0x80 or passwd_i > 0xBF then
105 while (i <= #passwd) do
106 local passwd_i = to_byte(passwd:sub(i, i));
107 if passwd_i > 0x7F then
109 local passwd_i_1 = to_byte(passwd:sub(i, i));
110 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
112 t_insert(p, to_char(passwd_i));
118 local function latin1toutf8(str)
120 for ch in gmatch(str, ".") do
123 t_insert(p, to_char(ch));
124 elseif (ch < 0xC0) then
125 t_insert(p, to_char(0xC2, ch));
127 t_insert(p, to_char(0xC3, ch - 64));
132 local function parse(data)
134 for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
140 local object = { mechanism = "DIGEST-MD5", realm = realm, password_handler = password_handler};
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"] = "";
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"], to_unicode(domain), 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
210 log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
211 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
216 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
218 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
220 local HA1 = md5(A1, true);
221 local HA2 = md5(A2, true);
223 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
224 local response_value = md5(KD, true);
226 if response_value == response["response"] then
228 A2 = ":"..protocol.."/"..domain;
233 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
234 local rspauth = md5(KD, true);
235 self.authenticated = true;
236 return "challenge", serialize({rspauth = rspauth});
238 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
240 elseif self.step == 3 then
241 if self.authenticated ~= nil then return "success"
242 else return "failure", "malformed-request" end
248 local function new_anonymous(realm, password_handler)
249 local object = { mechanism = "ANONYMOUS", realm = realm, password_handler = password_handler}
250 function object.feed(self, message)
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));