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
201
202
203
204
205
206
207
208
209
210
|
<?php
//####################################################################
//
// File: auth_ticket.inc.php
//
// By: Luc Germain, STI, Universite de Sherbrooke
// Date: 2004-02-17
//
//#####################################################################
//
//#####################################################################
//
// This file defines functions to generate cookie tickets compatible
// with the "mod_auth_tkt" apache module.
//
//#####################################################################
// Configuration
// Weather we encrypt the data or not
$ENCRYPT_COOKIE = true;
// File name where the secret key is stored
$SECRET_KEY_FILE = "/path/to/file.txt";
// Initial seed for calls to rand
if( !isset($SeedIsDone) ) {
srand((double)microtime()*1000000);
$SeedIsDone = true;
}
//---------------------------------------------------------------
// Functions
//---------------------------------------------------------------
//---------------------------------------------------------------
// $result = getSecretKey( );
//---------------------------------------------------------------
//
// Returns a string that contains the secret key used to sign the
// cookie. Read from the secret key file.
//
//---------------------------------------------------------------
function getSecretKey() {
global $SECRET_KEY_FILE;
$keyword = "TktAuthSecret";
$minKeyLength = 10;
$matches = array();
$secretKey = "";
$content = file_get_contents( $SECRET_KEY_FILE );
if( $content === FALSE ){
// Cannot read key file
stopOnError( "F0006" );
}
if( preg_match( "/^\s*$keyword\s+\"(.*?)\"/m",
$content, $matches ) ) {
$secretKey = $matches[1];
}
if( strlen( $secretKey ) < $minKeyLength ) {
// Key invalid or not found
stopOnError( "F0007" );
}
return( $secretKey );
}
//---------------------------------------------------------------
// $result = stopOnError( $code );
//---------------------------------------------------------------
//
// Display an error code in html and exit
//
//---------------------------------------------------------------
function stopOnError( $code ) {
echo " <p>The program encountered an unexpected error.</p>
<p>Error code: $code</p>";
exit( );
}
//---------------------------------------------------------------
// $result = getTKTHash( $ip, $user, $tokens, $data, $key,
// [, $base64 [, $ts]] );
//---------------------------------------------------------------
//
// Returns a string that contains the signed cookie.
//
// The cookie includes the ip address of the user, the user UID, the
// tokens, the user data and a time stamp. The cookie can be
// optionnally base64 encoded. The data is also crypted with the
// encode() function.
//
//---------------------------------------------------------------
function getTKTHash( $ip, $user, $tokens, $data, $key, $base64 = false, $ts = "" ) {
// set the timestamp to now
// unless a time is specified
if( $ts == "" ) {
$ts = time();
}
$ipts = pack( "NN", ip2long($ip), $ts );
// make the cookie signature
$digest0 = md5( $ipts . $key . $user . "\0" . $tokens . "\0" . $data );
$digest = md5( $digest0 . $key );
if( $tokens ){
$tkt = sprintf( "%s%08x%s!%s!%s", $digest, $ts,
encode( $user, $ts, 0 ),
encode( $tokens, $ts, 4 ),
encode( $data, $ts, 8 ) );
} else {
$tkt = sprintf( "%s%08x%s!%s", $digest, $ts,
encode( $user, $ts, 0 ),
encode( $data, $ts, 8 ) );
}
if( $base64 ) {
return( base64_encode( $tkt ) );
} else {
return( $tkt );
}
}
//---------------------------------------------------------------
// $result = encode( $data, $timestamp, $offset );
//---------------------------------------------------------------
//
// Returns a "crypted" version of the data. The length of the data is
// unchanged.
//
// The encryption is deactivated (the function simply returns the
// string unencrypted) if the configuration variable $ENCRYPT_COOKIE
// is not set to TRUE.
//
// The function implements a encryption algorithm that substitutes
// each character for another one using a key to compute the shift
// value. The key is generated from a hash of the timestamp of the
// cookie and the secret key. This key is used from the offset
// specified. This algorithm is reversed in the mod_auth_tkt apache
// module before using the data. This may not be strictly
// cryptographically secure, but should provide sufficient protection
// for the personnal data included in the cookie.
//
//---------------------------------------------------------------
function encode( $data, $timestamp, $offset ) {
$CHARS_TO_ENCODE = " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-.:";
$LENGTH = strlen( $CHARS_TO_ENCODE );
$md5key = md5( $timestamp . getSecretKey() );
$encoded = "";
global $ENCRYPT_COOKIE;
// check if encryption is activated
if( ! $ENCRYPT_COOKIE ) {
return $data;
}
// encode the data one caracter at a time
for( $i = 0; $i < strlen($data); $i++ ) {
$pos = strpos( $CHARS_TO_ENCODE, $data{$i} );
if( $pos === FALSE ) {
// skip characters that are not in list to encode
$encoded .= $data{$i};
} else {
$newPos = ($pos + (hexdec( $md5key{($offset + $i)%strlen($md5key)} )*7)) % $LENGTH;
$encoded .= $CHARS_TO_ENCODE{$newPos};
// print $data{$i} . " -> $newPos " . $CHARS_TO_ENCODE{$newPos} . "<br>";
}
}
// print "<br>md5key = $md5key<br>data = $data<br>encoded = $encoded";
return $encoded;
}
//---------------------------------------------------------------
// $result = file_get_contents( $filename, $use_include_path = 0 );
//---------------------------------------------------------------
//
// Returns the content of the file in a string, or false if there is
// an error.
//
// This function exists in PHP >= 4.3.0 only
//
//---------------------------------------------------------------
if( !function_exists( 'file_get_contents' ) ) {
function file_get_contents( $filename, $use_include_path = 0 ) {
$data = '';
$file = @fopen( $filename, "rb", $use_include_path );
if( $file ) {
while( !feof( $file ) ) {
$data .= fread( $file, 1024 );
}
fclose($file);
} else {
/* There was a problem opening the file. */
return FALSE;
}
return $data;
}
}
?>
|
