1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
-- sasl.lua v0.4
-- Copyright (C) 2008-2010 Tobias Markmann
--
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
--
-- * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
-- * 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.
-- * 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.
--
-- 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.
local s_match = string.match;
local type = type
local string = string
local base64 = require "util.encodings".base64;
local hmac_sha1 = require "util.hmac".sha1;
local sha1 = require "util.hashes".sha1;
local generate_uuid = require "util.uuid".generate;
local saslprep = require "util.encodings".stringprep.saslprep;
local log = require "util.logger".init("sasl");
local t_concat = table.concat;
local char = string.char;
local byte = string.byte;
module "scram"
--=========================
--SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
--[[
Supported Authentication Backends
scram-{MECH}:
function(username, realm)
return salted_password, iteration_count, salt, state;
end
]]
local default_i = 4096
local function bp( b )
local result = ""
for i=1, b:len() do
result = result.."\\"..b:byte(i)
end
return result
end
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;};
local result = {};
local function binaryXOR( a, b )
for i=1, #a do
local x, y = byte(a, i), byte(b, i);
local lowx, lowy = x % 16, y % 16;
local hix, hiy = (x - lowx) / 16, (y - lowy) / 16;
local lowr, hir = xor_map[lowx * 16 + lowy + 1], xor_map[hix * 16 + hiy + 1];
local r = hir * 16 + lowr;
result[i] = char(r)
end
return t_concat(result);
end
-- hash algorithm independent Hi(PBKDF2) implementation
local function Hi(hmac, str, salt, i)
local Ust = hmac(str, salt.."\0\0\0\1");
local res = Ust;
for n=1,i-1 do
local Und = hmac(str, Ust)
res = binaryXOR(res, Und)
Ust = Und
end
return res
end
local function validate_username(username)
-- check for forbidden char sequences
for eq in username:gmatch("=(.?.?)") do
if eq ~= "2D" and eq ~= "3D" then
return false
end
end
-- replace =2D with , and =3D with =
username = username:gsub("=2D", ",");
username = username:gsub("=3D", "=");
-- apply SASLprep
username = saslprep(username);
return username;
end
local function scram_gen(hash_name, H_f, HMAC_f)
local function scram_hash(self, message)
if not self.state then self["state"] = {} end
if not self.state.name then
-- we are processing client_first_message
local client_first_message = message;
-- TODO: more strict parsing of client_first_message
-- TODO: fail if authzid is provided, since we don't support them yet
self.state["client_first_message"] = client_first_message;
self.state["name"] = client_first_message:match("n=(.+),r=")
self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
self.state["gs2_cbind_flag"] = client_first_message:sub(1, 1)
-- we don't do any channel binding yet
if self.state.gs2_cbind_flag ~= "n" and self.state.gs2_cbind_flag ~= "y" then
return "failure", "malformed-request";
end
if not self.state.name or not self.state.clientnonce then
return "failure", "malformed-request", "Channel binding isn't support at this time.";
end
self.state.name = validate_username(self.state.name);
if not self.state.name then
log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
return "failure", "malformed-request", "Invalid username.";
end
self.state["servernonce"] = generate_uuid();
-- retreive credentials
if self.profile.plain then
local password, state = self.profile.plain(self.state.name, self.realm)
if state == nil then return "failure", "not-authorized"
elseif state == false then return "failure", "account-disabled" end
password = saslprep(password);
if not password then
log("debug", "Password violates SASLprep.");
return "failure", "not-authorized", "Invalid password."
end
self.state.salt = generate_uuid();
self.state.iteration_count = default_i;
self.state.salted_password = Hi(HMAC_f, password, self.state.salt, default_i);
elseif self.profile["scram_"..hash_name] then
local salted_password, iteration_count, salt, state = self.profile["scram-"..hash_name](self.state.name, self.realm);
if state == nil then return "failure", "not-authorized"
elseif state == false then return "failure", "account-disabled" end
self.state.salted_password = salted_password;
self.state.iteration_count = iteration_count;
self.state.salt = salt
end
local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..self.state.iteration_count;
self.state["server_first_message"] = server_first_message;
return "challenge", server_first_message
else
if type(message) ~= "string" then return "failure", "malformed-request" end
-- we are processing client_final_message
local client_final_message = message;
-- TODO: more strict parsing of client_final_message
self.state["proof"] = client_final_message:match("p=(.+)");
self.state["nonce"] = client_final_message:match("r=(.+),p=");
self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
end
if self.state.nonce ~= self.state.servernonce then
return "failure", "malformed-request", "Wrong nonce in client-second-message.";
end
local SaltedPassword = self.state.salted_password;
local ClientKey = HMAC_f(SaltedPassword, "Client Key")
local ServerKey = HMAC_f(SaltedPassword, "Server Key")
local StoredKey = H_f(ClientKey)
local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
local ClientSignature = HMAC_f(StoredKey, AuthMessage)
local ClientProof = binaryXOR(ClientKey, ClientSignature)
local ServerSignature = HMAC_f(ServerKey, AuthMessage)
if base64.encode(ClientProof) == self.state.proof then
local server_final_message = "v="..base64.encode(ServerSignature);
self["username"] = self.state.name;
return "success", server_final_message;
else
return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
end
end
end
return scram_hash;
end
function init(registerMechanism)
local function registerSCRAMMechanism(hash_name, hash, hmac_hash)
registerMechanism("SCRAM-"..hash_name, {"plain", "scram_"..(hash_name:lower())}, scram_gen(hash_name:lower(), hash, hmac_hash));
end
registerSCRAMMechanism("SHA-1", sha1, hmac_sha1);
end
return _M;
|
