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 -- Credentials handler:
34 -- Arguments: ("PLAIN", user, host, password)
35 -- Returns: true (success) | false (fail) | nil (user unknown)
36 local function new_plain(realm, credentials_handler)
37 local object = { mechanism = "PLAIN", realm = realm, credentials_handler = credentials_handler}
38 function object.feed(self, message)
39 if message == "" or message == nil then return "failure", "malformed-request" end
40 local response = message
41 local authorization = s_match(response, "([^%z]+)")
42 local authentication = s_match(response, "%z([^%z]+)%z")
43 local password = s_match(response, "%z[^%z]+%z([^%z]+)")
45 if authentication == nil or password == nil then return "failure", "malformed-request" end
46 self.username = authentication
47 local auth_success = self.credentials_handler("PLAIN", self.username, self.realm, password)
51 elseif auth_success == nil then
52 return "failure", "account-disabled"
54 return "failure", "not-authorized"
60 -- credentials_handler:
61 -- Arguments: (mechanism, node, domain, realm, decoder)
62 -- Returns: Password encoding, (plaintext) password
63 -- implementing RFC 2831
64 local function new_digest_md5(realm, credentials_handler)
65 --TODO complete support for authzid
67 local function serialize(message)
70 if type(message) ~= "table" then error("serialize needs an argument of type table.") end
72 -- testing all possible values
73 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
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["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
79 data = data:gsub(",$", "")
83 local function utf8tolatin1ifpossible(passwd)
86 local passwd_i = to_byte(passwd:sub(i, i));
87 if passwd_i > 0x7F then
88 if passwd_i < 0xC0 or passwd_i > 0xC3 then
92 passwd_i = to_byte(passwd:sub(i, i));
93 if passwd_i < 0x80 or passwd_i > 0xBF then
103 while (i <= #passwd) do
104 local passwd_i = to_byte(passwd:sub(i, i));
105 if passwd_i > 0x7F then
107 local passwd_i_1 = to_byte(passwd:sub(i, i));
108 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
110 t_insert(p, to_char(passwd_i));
116 local function latin1toutf8(str)
118 for ch in gmatch(str, ".") do
121 t_insert(p, to_char(ch));
122 elseif (ch < 0xC0) then
123 t_insert(p, to_char(0xC2, ch));
125 t_insert(p, to_char(0xC3, ch - 64));
130 local function parse(data)
132 for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
138 local object = { mechanism = "DIGEST-MD5", realm = realm, credentials_handler = credentials_handler};
140 object.nonce = generate_uuid();
142 object.nonce_count = {};
144 function object.feed(self, message)
145 self.step = self.step + 1;
146 if (self.step == 1) then
147 local challenge = serialize({ nonce = object.nonce,
150 algorithm = "md5-sess",
151 realm = self.realm});
152 return "challenge", challenge;
153 elseif (self.step == 2) then
154 local response = parse(message);
155 -- check for replay attack
156 if response["nc"] then
157 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
160 -- check for username, it's REQUIRED by RFC 2831
161 if not response["username"] then
162 return "failure", "malformed-request";
164 self["username"] = response["username"];
166 -- check for nonce, ...
167 if not response["nonce"] then
168 return "failure", "malformed-request";
170 -- check if it's the right nonce
171 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
174 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
175 if not response["qop"] then response["qop"] = "auth" end
177 if response["realm"] == nil or response["realm"] == "" then
178 response["realm"] = "";
179 elseif response["realm"] ~= self.realm then
180 return "failure", "not-authorized", "Incorrect realm value";
184 if response["charset"] == nil then
185 decoder = utf8tolatin1ifpossible;
186 elseif response["charset"] ~= "utf-8" then
187 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.";
192 if response["digest-uri"] then
193 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
194 if protocol == nil or domain == nil then return "failure", "malformed-request" end
196 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
199 --TODO maybe realm support
200 self.username = response["username"];
201 local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
202 if Y == nil then return "failure", "not-authorized"
203 elseif Y == false then return "failure", "account-disabled" end
205 if response.authzid then
206 if response.authzid == self.username.."@"..self.realm then
208 log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
209 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
214 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
216 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
218 local HA1 = md5(A1, true);
219 local HA2 = md5(A2, true);
221 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
222 local response_value = md5(KD, true);
224 if response_value == response["response"] then
226 A2 = ":"..protocol.."/"..domain;
231 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
232 local rspauth = md5(KD, true);
233 self.authenticated = true;
234 return "challenge", serialize({rspauth = rspauth});
236 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
238 elseif self.step == 3 then
239 if self.authenticated ~= nil then return "success"
240 else return "failure", "malformed-request" end
246 -- Credentials handler: Can be nil. If specified, should take the mechanism as
247 -- the only argument, and return true for OK, or false for not-OK (TODO)
248 local function new_anonymous(realm, credentials_handler)
249 local object = { mechanism = "ANONYMOUS", realm = realm, credentials_handler = credentials_handler}
250 function object.feed(self, message)
253 object["username"] = generate_uuid()
258 function new(mechanism, realm, credentials_handler)
260 if mechanism == "PLAIN" then object = new_plain(realm, credentials_handler)
261 elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, credentials_handler)
262 elseif mechanism == "ANONYMOUS" then object = new_anonymous(realm, credentials_handler)
264 log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));