prosody
1112871916eb
util/sasl/digest-md5.lua

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util/sasl/digest-md5.lua @ 2186:1112871916eb sasl

Move each mechanism in an own file.
author Tobias Markmann <tm@ayena.de>
date Thu, 12 Nov 2009 21:57:37 +0100
child 2188:1fd38975addd
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2185:e92339c48ee6 2186:1112871916eb
1 -- sasl.lua v0.4
2 -- Copyright (C) 2008-2009 Tobias Markmann
3 --
4 -- All rights reserved.
5 --
6 -- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
7 --
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.
11 --
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.
13
14
15 --=========================
16 --SASL DIGEST-MD5 according to RFC 2831
17 local function sasl_mechanism_digest_md5(self, message)
18 --TODO complete support for authzid
19
20 local function serialize(message)
21 local data = ""
22
23 if type(message) ~= "table" then error("serialize needs an argument of type table.") end
24
25 -- testing all possible values
26 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end
27 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end
28 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end
29 if message["charset"] then data = data..[[charset=]]..message.charset.."," end
30 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end
31 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end
32 data = data:gsub(",$", "")
33 return data
34 end
35
36 local function utf8tolatin1ifpossible(passwd)
37 local i = 1;
38 while i <= #passwd do
39 local passwd_i = to_byte(passwd:sub(i, i));
40 if passwd_i > 0x7F then
41 if passwd_i < 0xC0 or passwd_i > 0xC3 then
42 return passwd;
43 end
44 i = i + 1;
45 passwd_i = to_byte(passwd:sub(i, i));
46 if passwd_i < 0x80 or passwd_i > 0xBF then
47 return passwd;
48 end
49 end
50 i = i + 1;
51 end
52
53 local p = {};
54 local j = 0;
55 i = 1;
56 while (i <= #passwd) do
57 local passwd_i = to_byte(passwd:sub(i, i));
58 if passwd_i > 0x7F then
59 i = i + 1;
60 local passwd_i_1 = to_byte(passwd:sub(i, i));
61 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever
62 else
63 t_insert(p, to_char(passwd_i));
64 end
65 i = i + 1;
66 end
67 return t_concat(p);
68 end
69 local function latin1toutf8(str)
70 local p = {};
71 for ch in gmatch(str, ".") do
72 ch = to_byte(ch);
73 if (ch < 0x80) then
74 t_insert(p, to_char(ch));
75 elseif (ch < 0xC0) then
76 t_insert(p, to_char(0xC2, ch));
77 else
78 t_insert(p, to_char(0xC3, ch - 64));
79 end
80 end
81 return t_concat(p);
82 end
83 local function parse(data)
84 local message = {}
85 for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder
86 message[k] = v;
87 end
88 return message;
89 end
90
91 if not self.nonce then
92 self.nonce = generate_uuid();
93 self.step = 0;
94 self.nonce_count = {};
95 end
96
97 self.step = self.step + 1;
98 if (self.step == 1) then
99 local challenge = serialize({ nonce = object.nonce,
100 qop = "auth",
101 charset = "utf-8",
102 algorithm = "md5-sess",
103 realm = self.realm});
104 return "challenge", challenge;
105 elseif (self.step == 2) then
106 local response = parse(message);
107 -- check for replay attack
108 if response["nc"] then
109 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
110 end
111
112 -- check for username, it's REQUIRED by RFC 2831
113 if not response["username"] then
114 return "failure", "malformed-request";
115 end
116 self["username"] = response["username"];
117
118 -- check for nonce, ...
119 if not response["nonce"] then
120 return "failure", "malformed-request";
121 else
122 -- check if it's the right nonce
123 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
124 end
125
126 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
127 if not response["qop"] then response["qop"] = "auth" end
128
129 if response["realm"] == nil or response["realm"] == "" then
130 response["realm"] = "";
131 elseif response["realm"] ~= self.realm then
132 return "failure", "not-authorized", "Incorrect realm value";
133 end
134
135 local decoder;
136 if response["charset"] == nil then
137 decoder = utf8tolatin1ifpossible;
138 elseif response["charset"] ~= "utf-8" then
139 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.";
140 end
141
142 local domain = "";
143 local protocol = "";
144 if response["digest-uri"] then
145 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
146 if protocol == nil or domain == nil then return "failure", "malformed-request" end
147 else
148 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
149 end
150
151 --TODO maybe realm support
152 self.username = response["username"];
153 local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
154 if Y == nil then return "failure", "not-authorized"
155 elseif Y == false then return "failure", "account-disabled" end
156 local A1 = "";
157 if response.authzid then
158 if response.authzid == self.username.."@"..self.realm then
159 -- COMPAT
160 log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
161 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
162 else
163 A1 = "?";
164 end
165 else
166 A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
167 end
168 local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
169
170 local HA1 = md5(A1, true);
171 local HA2 = md5(A2, true);
172
173 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
174 local response_value = md5(KD, true);
175
176 if response_value == response["response"] then
177 -- calculate rspauth
178 A2 = ":"..protocol.."/"..domain;
179
180 HA1 = md5(A1, true);
181 HA2 = md5(A2, true);
182
183 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
184 local rspauth = md5(KD, true);
185 self.authenticated = true;
186 return "challenge", serialize({rspauth = rspauth});
187 else
188 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
189 end
190 elseif self.step == 3 then
191 if self.authenticated ~= nil then return "success"
192 else return "failure", "malformed-request" end
193 end
194 end