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 s_match = string.match;
17 local base64 = require "util.encodings".base64;
18 local hmac_sha1 = require "util.hmac".sha1;
19 local sha1 = require "util.hashes".sha1;
20 local generate_uuid = require "util.uuid".generate;
21 local saslprep = require "util.encodings".stringprep.saslprep;
22 local log = require "util.logger".init("sasl");
23 local t_concat = table.concat;
24 local char = string.char;
25 local byte = string.byte;
29 --=========================
30 --SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
31 local default_i = 4096
33 local function bp( b )
36 result = result.."\\"..b:byte(i)
41 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;};
44 local function binaryXOR( a, b )
46 local x, y = byte(a, i), byte(b, i);
47 local lowx, lowy = x % 16, y % 16;
48 local hix, hiy = (x - lowx) / 16, (y - lowy) / 16;
49 local lowr, hir = xor_map[lowx * 16 + lowy + 1], xor_map[hix * 16 + hiy + 1];
50 local r = hir * 16 + lowr;
53 return t_concat(result);
56 -- hash algorithm independent Hi(PBKDF2) implementation
57 local function Hi(hmac, str, salt, i)
58 local Ust = hmac(str, salt.."\0\0\0\1");
61 local Und = hmac(str, Ust)
62 res = binaryXOR(res, Und)
68 local function validate_username(username)
69 -- check for forbidden char sequences
70 for eq in username:gmatch("=(.?.?)") do
71 if eq ~= "2D" and eq ~= "3D" then
76 -- replace =2D with , and =3D with =
77 username = username:gsub("=2D", ",");
78 username = username:gsub("=3D", "=");
81 username = saslprep(username);
85 local function scram_sha_1(self, message)
86 if not self.state then self["state"] = {} end
88 if not self.state.name then
89 -- we are processing client_first_message
90 local client_first_message = message;
91 self.state["client_first_message"] = client_first_message;
92 self.state["name"] = client_first_message:match("n=(.+),r=")
93 self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
95 if not self.state.name or not self.state.clientnonce then
96 return "failure", "malformed-request";
99 self.state.name = validate_username(self.state.name);
100 if not self.state.name then
101 log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
102 return "failure", "malformed-request", "Invalid username.";
105 self.state["servernonce"] = generate_uuid();
106 self.state["salt"] = generate_uuid();
108 local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
109 self.state["server_first_message"] = server_first_message;
110 return "challenge", server_first_message
112 if type(message) ~= "string" then return "failure", "malformed-request" end
113 -- we are processing client_final_message
114 local client_final_message = message;
116 self.state["proof"] = client_final_message:match("p=(.+)");
117 self.state["nonce"] = client_final_message:match("r=(.+),p=");
118 self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
119 if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
120 return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
123 local password, state;
124 if self.profile.plain then
125 password, state = self.profile.plain(self.state.name, self.realm)
126 if state == nil then return "failure", "not-authorized"
127 elseif state == false then return "failure", "account-disabled" end
128 password = saslprep(password);
130 log("debug", "Password violates SASLprep.");
131 return "failure", "not-authorized", "Invalid password."
135 local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
136 local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
137 local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
138 local StoredKey = sha1(ClientKey)
139 local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
140 local ClientSignature = hmac_sha1(StoredKey, AuthMessage)
141 local ClientProof = binaryXOR(ClientKey, ClientSignature)
142 local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
144 if base64.encode(ClientProof) == self.state.proof then
145 local server_final_message = "v="..base64.encode(ServerSignature);
146 self["username"] = self.state.name;
147 return "success", server_final_message;
149 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
154 function init(registerMechanism)
155 registerMechanism("SCRAM-SHA-1", {"plain"}, scram_sha_1);