2 -- Copyright (C) 2008-2010 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.
14 local tostring = tostring;
17 local s_gmatch = string.gmatch;
18 local s_match = string.match;
19 local t_concat = table.concat;
20 local t_insert = table.insert;
21 local to_byte, to_char = string.byte, string.char;
23 local md5 = require "util.hashes".md5;
24 local log = require "util.logger".init("sasl");
25 local generate_uuid = require "util.uuid".generate;
27 module "sasl.digest-md5"
29 --=========================
30 --SASL DIGEST-MD5 according to RFC 2831
33 Supported Authentication Backends
36 function(username, domain, realm, encoding) -- domain and realm are usually the same; for some broken
37 -- implementations it's not
38 return digesthash, state;
42 function(username, domain, realm, encoding, digesthash)
43 return true or false, state;
47 local function digest(self, message)
48 --TODO complete support for authzid
50 local function serialize(message)
53 -- testing all possible values
54 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
55 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
56 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
57 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
58 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
59 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
60 data = data:gsub(",$", "")
64 local function utf8tolatin1ifpossible(passwd)
67 local passwd_i = to_byte(passwd:sub(i, i));
68 if passwd_i > 0x7F then
69 if passwd_i < 0xC0 or passwd_i > 0xC3 then
73 passwd_i = to_byte(passwd:sub(i, i));
74 if passwd_i < 0x80 or passwd_i > 0xBF then
84 while (i <= #passwd) do
85 local passwd_i = to_byte(passwd:sub(i, i));
86 if passwd_i > 0x7F then
88 local passwd_i_1 = to_byte(passwd:sub(i, i));
89 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
91 t_insert(p, to_char(passwd_i));
97 local function latin1toutf8(str)
99 for ch in s_gmatch(str, ".") do
102 t_insert(p, to_char(ch));
103 elseif (ch < 0xC0) then
104 t_insert(p, to_char(0xC2, ch));
106 t_insert(p, to_char(0xC3, ch - 64));
111 local function parse(data)
113 -- COMPAT: %z in the pattern to work around jwchat bug (sends "charset=utf-8\0")
114 for k, v in s_gmatch(data, [[([%w%-]+)="?([^",%z]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
120 if not self.nonce then
121 self.nonce = generate_uuid();
123 self.nonce_count = {};
126 self.step = self.step + 1;
127 if (self.step == 1) then
128 local challenge = serialize({ nonce = self.nonce,
131 algorithm = "md5-sess",
132 realm = self.realm});
133 return "challenge", challenge;
134 elseif (self.step == 2) then
135 local response = parse(message);
136 -- check for replay attack
137 if response["nc"] then
138 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
141 -- check for username, it's REQUIRED by RFC 2831
142 if not response["username"] then
143 return "failure", "malformed-request";
145 self["username"] = response["username"];
147 -- check for nonce, ...
148 if not response["nonce"] then
149 return "failure", "malformed-request";
151 -- check if it's the right nonce
152 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
155 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
156 if not response["qop"] then response["qop"] = "auth" end
158 if response["realm"] == nil or response["realm"] == "" then
159 response["realm"] = "";
160 elseif response["realm"] ~= self.realm then
161 return "failure", "not-authorized", "Incorrect realm value";
165 if response["charset"] == nil then
166 decoder = utf8tolatin1ifpossible;
167 elseif response["charset"] ~= "utf-8" then
168 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.";
173 if response["digest-uri"] then
174 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
175 if protocol == nil or domain == nil then return "failure", "malformed-request" end
177 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
180 --TODO maybe realm support
181 self.username = response["username"];
183 if self.profile.plain then
184 local password, state = self.profile.plain(self, response["username"], self.realm)
185 if state == nil then return "failure", "not-authorized"
186 elseif state == false then return "failure", "account-disabled" end
187 Y = md5(response["username"]..":"..response["realm"]..":"..password);
188 elseif self.profile["digest-md5"] then
189 Y, state = self.profile["digest-md5"](self, response["username"], self.realm, response["realm"], response["charset"])
190 if state == nil then return "failure", "not-authorized"
191 elseif state == false then return "failure", "account-disabled" end
192 elseif self.profile["digest-md5-test"] then
195 --local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
196 --if Y == nil then return "failure", "not-authorized"
197 --elseif Y == false then return "failure", "account-disabled" end
199 if response.authzid then
200 if response.authzid == self.username or response.authzid == self.username.."@"..self.realm then
202 log("warn", "Client is violating RFC 3920 (section 6.1, point 7).");
203 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
205 return "failure", "invalid-authzid";
208 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
210 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
212 local HA1 = md5(A1, true);
213 local HA2 = md5(A2, true);
215 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
216 local response_value = md5(KD, true);
218 if response_value == response["response"] then
220 A2 = ":"..protocol.."/"..domain;
225 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
226 local rspauth = md5(KD, true);
227 self.authenticated = true;
228 --TODO: considering sending the rspauth in a success node for saving one roundtrip; allowed according to http://tools.ietf.org/html/draft-saintandre-rfc3920bis-09#section-7.3.6
229 return "challenge", serialize({rspauth = rspauth});
231 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
233 elseif self.step == 3 then
234 if self.authenticated ~= nil then return "success"
235 else return "failure", "malformed-request" end
239 function init(registerMechanism)
240 registerMechanism("DIGEST-MD5", {"plain"}, digest);