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 nodeprep = require "util.encodings".stringprep.nodeprep;
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 RFC 5802
34 Supported Authentication Backends
37 -- MECH being a standard hash name (like those at IANA's hash registry) with '-' replaced with '_'
38 function(username, realm)
39 return stored_key, server_key, iteration_count, salt, state;
43 local default_i = 4096
45 local function bp( b )
48 result = result.."\\"..b:byte(i)
53 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;};
56 local function binaryXOR( a, b )
58 local x, y = byte(a, i), byte(b, i);
59 local lowx, lowy = x % 16, y % 16;
60 local hix, hiy = (x - lowx) / 16, (y - lowy) / 16;
61 local lowr, hir = xor_map[lowx * 16 + lowy + 1], xor_map[hix * 16 + hiy + 1];
62 local r = hir * 16 + lowr;
65 return t_concat(result);
68 -- hash algorithm independent Hi(PBKDF2) implementation
69 function Hi(hmac, str, salt, i)
70 local Ust = hmac(str, salt.."\0\0\0\1");
73 local Und = hmac(str, Ust)
74 res = binaryXOR(res, Und)
80 local function validate_username(username, _nodeprep)
81 -- check for forbidden char sequences
82 for eq in username:gmatch("=(.?.?)") do
83 if eq ~= "2C" and eq ~= "3D" then
88 -- replace =2C with , and =3D with =
89 username = username:gsub("=2C", ",");
90 username = username:gsub("=3D", "=");
93 username = saslprep(username);
95 if username and _nodeprep ~= false then
96 username = (_nodeprep or nodeprep)(username);
99 return username and #username>0 and username;
102 local function hashprep(hashname)
103 return hashname:lower():gsub("-", "_");
106 function getAuthenticationDatabaseSHA1(password, salt, iteration_count)
107 if type(password) ~= "string" or type(salt) ~= "string" or type(iteration_count) ~= "number" then
108 return false, "inappropriate argument types"
110 if iteration_count < 4096 then
111 log("warn", "Iteration count < 4096 which is the suggested minimum according to RFC 5802.")
113 local salted_password = Hi(hmac_sha1, password, salt, iteration_count);
114 local stored_key = sha1(hmac_sha1(salted_password, "Client Key"))
115 local server_key = hmac_sha1(salted_password, "Server Key");
116 return true, stored_key, server_key
119 local function scram_gen(hash_name, H_f, HMAC_f)
120 local function scram_hash(self, message)
121 if not self.state then self["state"] = {} end
123 if type(message) ~= "string" or #message == 0 then return "failure", "malformed-request" end
124 if not self.state.name then
125 -- we are processing client_first_message
126 local client_first_message = message;
128 -- TODO: fail if authzid is provided, since we don't support them yet
129 self.state["client_first_message"] = client_first_message;
130 self.state["gs2_cbind_flag"], self.state["authzid"], self.state["name"], self.state["clientnonce"]
131 = client_first_message:match("^(%a),(.*),n=(.*),r=([^,]*).*");
133 -- we don't do any channel binding yet
134 if self.state.gs2_cbind_flag ~= "n" and self.state.gs2_cbind_flag ~= "y" then
135 return "failure", "malformed-request";
138 if not self.state.name or not self.state.clientnonce then
139 return "failure", "malformed-request", "Channel binding isn't support at this time.";
142 self.state.name = validate_username(self.state.name, self.profile.nodeprep);
143 if not self.state.name then
144 log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
145 return "failure", "malformed-request", "Invalid username.";
148 self.state["servernonce"] = generate_uuid();
150 -- retreive credentials
151 if self.profile.plain then
152 local password, state = self.profile.plain(self, self.state.name, self.realm)
153 if state == nil then return "failure", "not-authorized"
154 elseif state == false then return "failure", "account-disabled" end
156 password = saslprep(password);
158 log("debug", "Password violates SASLprep.");
159 return "failure", "not-authorized", "Invalid password."
162 self.state.salt = generate_uuid();
163 self.state.iteration_count = default_i;
166 succ, self.state.stored_key, self.state.server_key = getAuthenticationDatabaseSHA1(password, self.state.salt, default_i, self.state.iteration_count);
168 log("error", "Generating authentication database failed. Reason: %s", self.state.stored_key);
169 return "failure", "temporary-auth-failure";
171 elseif self.profile["scram_"..hashprep(hash_name)] then
172 local stored_key, server_key, iteration_count, salt, state = self.profile["scram_"..hashprep(hash_name)](self, self.state.name, self.realm);
173 if state == nil then return "failure", "not-authorized"
174 elseif state == false then return "failure", "account-disabled" end
176 self.state.stored_key = stored_key;
177 self.state.server_key = server_key;
178 self.state.iteration_count = iteration_count;
179 self.state.salt = salt
182 local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..self.state.iteration_count;
183 self.state["server_first_message"] = server_first_message;
184 return "challenge", server_first_message
186 -- we are processing client_final_message
187 local client_final_message = message;
189 self.state["channelbinding"], self.state["nonce"], self.state["proof"] = client_final_message:match("^c=(.*),r=(.*),.*p=(.*)");
191 if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
192 return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
195 if self.state.nonce ~= self.state.clientnonce..self.state.servernonce then
196 return "failure", "malformed-request", "Wrong nonce in client-final-message.";
199 local ServerKey = self.state.server_key;
200 local StoredKey = self.state.stored_key;
202 local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
203 local ClientSignature = HMAC_f(StoredKey, AuthMessage)
204 local ClientKey = binaryXOR(ClientSignature, base64.decode(self.state.proof))
205 local ServerSignature = HMAC_f(ServerKey, AuthMessage)
207 if StoredKey == H_f(ClientKey) then
208 local server_final_message = "v="..base64.encode(ServerSignature);
209 self["username"] = self.state.name;
210 return "success", server_final_message;
212 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
219 function init(registerMechanism)
220 local function registerSCRAMMechanism(hash_name, hash, hmac_hash)
221 registerMechanism("SCRAM-"..hash_name, {"plain", "scram_"..(hashprep(hash_name))}, scram_gen(hash_name:lower(), hash, hmac_hash));
224 registerSCRAMMechanism("SHA-1", sha1, hmac_sha1);