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 -- COMPAT: %z in the pattern to work around jwchat bug (sends "charset=utf-8\0")
133 for k, v in gmatch(data, [[([%w%-]+)="?([^",%z]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
139 local object = { mechanism = "DIGEST-MD5", realm = realm, credentials_handler = credentials_handler};
141 object.nonce = generate_uuid();
143 object.nonce_count = {};
145 function object.feed(self, message)
146 self.step = self.step + 1;
147 if (self.step == 1) then
148 local challenge = serialize({ nonce = object.nonce,
151 algorithm = "md5-sess",
152 realm = self.realm});
153 return "challenge", challenge;
154 elseif (self.step == 2) then
155 local response = parse(message);
156 -- check for replay attack
157 if response["nc"] then
158 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
161 -- check for username, it's REQUIRED by RFC 2831
162 if not response["username"] then
163 return "failure", "malformed-request";
165 self["username"] = response["username"];
167 -- check for nonce, ...
168 if not response["nonce"] then
169 return "failure", "malformed-request";
171 -- check if it's the right nonce
172 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
175 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
176 if not response["qop"] then response["qop"] = "auth" end
178 if response["realm"] == nil or response["realm"] == "" then
179 response["realm"] = "";
180 elseif response["realm"] ~= self.realm then
181 return "failure", "not-authorized", "Incorrect realm value";
185 if response["charset"] == nil then
186 decoder = utf8tolatin1ifpossible;
187 elseif response["charset"] ~= "utf-8" then
188 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.";
193 if response["digest-uri"] then
194 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
195 if protocol == nil or domain == nil then return "failure", "malformed-request" end
197 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
200 --TODO maybe realm support
201 self.username = response["username"];
202 local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
203 if Y == nil then return "failure", "not-authorized"
204 elseif Y == false then return "failure", "account-disabled" end
206 if response.authzid then
207 if response.authzid == self.username or response.authzid == self.username.."@"..self.realm then
209 log("warn", "Client is violating RFC 3920 (section 6.1, point 7).");
210 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
212 return "failure", "invalid-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 -- Credentials handler: Can be nil. If specified, should take the mechanism as
248 -- the only argument, and return true for OK, or false for not-OK (TODO)
249 local function new_anonymous(realm, credentials_handler)
250 local object = { mechanism = "ANONYMOUS", realm = realm, credentials_handler = credentials_handler}
251 function object.feed(self, message)
254 object["username"] = generate_uuid()
259 function new(mechanism, realm, credentials_handler)
261 if mechanism == "PLAIN" then object = new_plain(realm, credentials_handler)
262 elseif mechanism == "DIGEST-MD5" then object = new_digest_md5(realm, credentials_handler)
263 elseif mechanism == "ANONYMOUS" then object = new_anonymous(realm, credentials_handler)
265 log("debug", "Unsupported SASL mechanism: "..tostring(mechanism));