prosody
27441b099984
util/sasl/scram.lua

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util/sasl/scram.lua @ 2281:27441b099984

Merge with tip.
author Tobias Markmann <tm@ayena.de>
date Sun, 29 Nov 2009 21:33:37 +0100
parent 2255:92e329e1cd99
child 2265:7fe644057dc2
comparison
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2280:0b0fe49e5251 2281:27441b099984
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 local s_match = string.match;
15 local type = type
16 local string = string
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
25 module "scram"
26
27 --=========================
28 --SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
29 local default_i = 4096
30
31 local function bp( b )
32 local result = ""
33 for i=1, b:len() do
34 result = result.."\\"..b:byte(i)
35 end
36 return result
37 end
38
39 local function binaryXOR( a, b )
40 if a:len() > b:len() then
41 b = string.rep("\0", a:len() - b:len())..b
42 elseif string.len(a) < string.len(b) then
43 a = string.rep("\0", b:len() - a:len())..a
44 end
45 local result = ""
46 for i=1, a:len() do
47 result = result..string.char(xor(a:byte(i), b:byte(i)))
48 end
49 return result
50 end
51
52 -- hash algorithm independent Hi(PBKDF2) implementation
53 local function Hi(hmac, str, salt, i)
54 local Ust = hmac(str, salt.."\0\0\0\1");
55 local res = Ust;
56 for n=1,i-1 do
57 local Und = hmac(str, Ust)
58 res = binaryXOR(res, Und)
59 Ust = Und
60 end
61 return res
62 end
63
64 local function validate_username(username)
65 -- check for forbidden char sequences
66 for eq in username:gmatch("=(.?.?)") do
67 if eq ~= "2D" and eq ~= "3D" then
68 return false
69 end
70 end
71
72 -- replace =2D with , and =3D with =
73 username:gsub("=2D", ",");
74 username:gsub("=3D", "=");
75
76 -- apply SASLprep
77 username = saslprep(username);
78 return username;
79 end
80
81 local function scram_sha_1(self, message)
82 if not self.state then self["state"] = {} end
83
84 if not self.state.name then
85 -- we are processing client_first_message
86 local client_first_message = message;
87 self.state["client_first_message"] = client_first_message;
88 self.state["name"] = client_first_message:match("n=(.+),r=")
89 self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
90
91 if not self.state.name or not self.state.clientnonce then
92 return "failure", "malformed-request";
93 end
94
95 self.state.name = validate_username(self.state.name);
96 if not self.state.name then
97 log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
98 return "failure", "malformed-request", "Invalid username.";
99 end
100
101 self.state["servernonce"] = generate_uuid();
102 self.state["salt"] = generate_uuid();
103
104 local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
105 self.state["server_first_message"] = server_first_message;
106 return "challenge", server_first_message
107 else
108 if type(message) ~= "string" then return "failure", "malformed-request" end
109 -- we are processing client_final_message
110 local client_final_message = message;
111
112 self.state["proof"] = client_final_message:match("p=(.+)");
113 self.state["nonce"] = client_final_message:match("r=(.+),p=");
114 self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
115 if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
116 return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
117 end
118
119 local password;
120 if self.profile.plain then
121 local password, state = self.profile.plain(self.state.name, self.realm)
122 if state == nil then return "failure", "not-authorized"
123 elseif state == false then return "failure", "account-disabled" end
124 password = saslprep(password);
125 if not password then
126 log("debug", "Password violates SASLprep.");
127 return "failure", "not-authorized", "Invalid password."
128 end
129 end
130
131 local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
132 local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
133 local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
134 local StoredKey = sha1(ClientKey)
135 local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
136 local ClientSignature = hmac_sha1(StoredKey, AuthMessage)
137 local ClientProof = binaryXOR(ClientKey, ClientSignature)
138 local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
139
140 if base64.encode(ClientProof) == self.state.proof then
141 local server_final_message = "v="..base64.encode(ServerSignature);
142 self["username"] = self.state.name;
143 return "success", server_final_message;
144 else
145 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
146 end
147 end
148 end
149
150 function init(registerMechanism)
151 registerMechanism("SCRAM-SHA-1", {"plain"}, scram_sha_1);
152 end
153
154 return _M;