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.
14 local s_match = string.match;
17 local base64 = require "util.encodings".base64;
18 local xor = require "bit".bxor
19 local hmac_sha1 = require "util.hmac".sha1;
20 local sha1 = require "util.hashes".sha1;
21 local generate_uuid = require "util.uuid".generate;
22 local saslprep = require "util.encodings".stringprep.saslprep;
23 local log = require "util.logger".init("sasl");
24 local t_concat = table.concat;
25 local char = string.char;
26 local byte = string.byte;
30 --=========================
31 --SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
32 local default_i = 4096
34 local function bp( b )
37 result = result.."\\"..b:byte(i)
42 local xor_map = {0;1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;1;0;3;2;5;4;7;6;9;8;11;10;13;12;15;14;2;3;0;1;6;7;4;5;10;11;8;9;14;15;12;13;3;2;1;0;7;6;5;4;11;10;9;8;15;14;13;12;4;5;6;7;0;1;2;3;12;13;14;15;8;9;10;11;5;4;7;6;1;0;3;2;13;12;15;14;9;8;11;10;6;7;4;5;2;3;0;1;14;15;12;13;10;11;8;9;7;6;5;4;3;2;1;0;15;14;13;12;11;10;9;8;8;9;10;11;12;13;14;15;0;1;2;3;4;5;6;7;9;8;11;10;13;12;15;14;1;0;3;2;5;4;7;6;10;11;8;9;14;15;12;13;2;3;0;1;6;7;4;5;11;10;9;8;15;14;13;12;3;2;1;0;7;6;5;4;12;13;14;15;8;9;10;11;4;5;6;7;0;1;2;3;13;12;15;14;9;8;11;10;5;4;7;6;1;0;3;2;14;15;12;13;10;11;8;9;6;7;4;5;2;3;0;1;15;14;13;12;11;10;9;8;7;6;5;4;3;2;1;0;};
45 local function binaryXOR( a, b )
47 local x, y = byte(a, i), byte(b, i);
48 local lowx, lowy = x % 16, y % 16;
49 local hix, hiy = (x - lowx) / 16, (y - lowy) / 16;
50 local lowr, hir = xor_map[lowx * 16 + lowy + 1], xor_map[hix * 16 + hiy + 1];
51 local r = hir * 16 + lowr;
54 return t_concat(result);
57 -- hash algorithm independent Hi(PBKDF2) implementation
58 local function Hi(hmac, str, salt, i)
59 local Ust = hmac(str, salt.."\0\0\0\1");
62 local Und = hmac(str, Ust)
63 res = binaryXOR(res, Und)
69 local function validate_username(username)
70 -- check for forbidden char sequences
71 for eq in username:gmatch("=(.?.?)") do
72 if eq ~= "2D" and eq ~= "3D" then
77 -- replace =2D with , and =3D with =
78 username = username:gsub("=2D", ",");
79 username = username:gsub("=3D", "=");
82 username = saslprep(username);
86 local function scram_sha_1(self, message)
87 if not self.state then self["state"] = {} end
89 if not self.state.name then
90 -- we are processing client_first_message
91 local client_first_message = message;
92 self.state["client_first_message"] = client_first_message;
93 self.state["name"] = client_first_message:match("n=(.+),r=")
94 self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
96 if not self.state.name or not self.state.clientnonce then
97 return "failure", "malformed-request";
100 self.state.name = validate_username(self.state.name);
101 if not self.state.name then
102 log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
103 return "failure", "malformed-request", "Invalid username.";
106 self.state["servernonce"] = generate_uuid();
107 self.state["salt"] = generate_uuid();
109 local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
110 self.state["server_first_message"] = server_first_message;
111 return "challenge", server_first_message
113 if type(message) ~= "string" then return "failure", "malformed-request" end
114 -- we are processing client_final_message
115 local client_final_message = message;
117 self.state["proof"] = client_final_message:match("p=(.+)");
118 self.state["nonce"] = client_final_message:match("r=(.+),p=");
119 self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
120 if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
121 return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
124 local password, state;
125 if self.profile.plain then
126 password, state = self.profile.plain(self.state.name, self.realm)
127 if state == nil then return "failure", "not-authorized"
128 elseif state == false then return "failure", "account-disabled" end
129 password = saslprep(password);
131 log("debug", "Password violates SASLprep.");
132 return "failure", "not-authorized", "Invalid password."
136 local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
137 local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
138 local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
139 local StoredKey = sha1(ClientKey)
140 local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
141 local ClientSignature = hmac_sha1(StoredKey, AuthMessage)
142 local ClientProof = binaryXOR(ClientKey, ClientSignature)
143 local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
145 if base64.encode(ClientProof) == self.state.proof then
146 local server_final_message = "v="..base64.encode(ServerSignature);
147 self["username"] = self.state.name;
148 return "success", server_final_message;
150 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
155 function init(registerMechanism)
156 registerMechanism("SCRAM-SHA-1", {"plain"}, scram_sha_1);