This file is indexed.

/usr/share/php/Crypt/Random.php is in php-seclib 1.0.5-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
<?php

/**
 * Random Number Generator
 *
 * The idea behind this function is that it can be easily replaced with your own crypt_random_string()
 * function. eg. maybe you have a better source of entropy for creating the initial states or whatever.
 *
 * PHP versions 4 and 5
 *
 * Here's a short example of how to use this library:
 * <code>
 * <?php
 *    include 'Crypt/Random.php';
 *
 *    echo bin2hex(crypt_random_string(8));
 * ?>
 * </code>
 *
 * LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @category  Crypt
 * @package   Crypt_Random
 * @author    Jim Wigginton <terrafrost@php.net>
 * @copyright 2007 Jim Wigginton
 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
 * @link      http://phpseclib.sourceforge.net
 */

// laravel is a PHP framework that utilizes phpseclib. laravel workbenches may, independently,
// have phpseclib as a requirement as well. if you're developing such a program you may encounter
// a "Cannot redeclare crypt_random_string()" error.
if (!function_exists('crypt_random_string')) {
    /**
     * "Is Windows" test
     *
     * @access private
     */
    define('CRYPT_RANDOM_IS_WINDOWS', strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');

    /**
     * Generate a random string.
     *
     * Although microoptimizations are generally discouraged as they impair readability this function is ripe with
     * microoptimizations because this function has the potential of being called a huge number of times.
     * eg. for RSA key generation.
     *
     * @param int $length
     * @return string
     * @access public
     */
    function crypt_random_string($length)
    {
        if (CRYPT_RANDOM_IS_WINDOWS) {
            // method 1. prior to PHP 5.3, mcrypt_create_iv() would call rand() on windows
            if (extension_loaded('mcrypt') && version_compare(PHP_VERSION, '5.3.0', '>=')) {
                return mcrypt_create_iv($length);
            }
            // method 2. openssl_random_pseudo_bytes was introduced in PHP 5.3.0 but prior to PHP 5.3.4 there was,
            // to quote <http://php.net/ChangeLog-5.php#5.3.4>, "possible blocking behavior". as of 5.3.4
            // openssl_random_pseudo_bytes and mcrypt_create_iv do the exact same thing on Windows. ie. they both
            // call php_win32_get_random_bytes():
            //
            // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/openssl/openssl.c#L5008
            // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/mcrypt/mcrypt.c#L1392
            //
            // php_win32_get_random_bytes() is defined thusly:
            //
            // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/win32/winutil.c#L80
            //
            // we're calling it, all the same, in the off chance that the mcrypt extension is not available
            if (extension_loaded('openssl') && version_compare(PHP_VERSION, '5.3.4', '>=')) {
                return openssl_random_pseudo_bytes($length);
            }
        } else {
            // method 1. the fastest
            if (extension_loaded('openssl') && version_compare(PHP_VERSION, '5.3.0', '>=')) {
                return openssl_random_pseudo_bytes($length);
            }
            // method 2
            static $fp = true;
            if ($fp === true) {
                // warning's will be output unles the error suppression operator is used. errors such as
                // "open_basedir restriction in effect", "Permission denied", "No such file or directory", etc.
                $fp = @fopen('/dev/urandom', 'rb');
            }
            if ($fp !== true && $fp !== false) { // surprisingly faster than !is_bool() or is_resource()
                return fread($fp, $length);
            }
            // method 3. pretty much does the same thing as method 2 per the following url:
            // https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/mcrypt/mcrypt.c#L1391
            // surprisingly slower than method 2. maybe that's because mcrypt_create_iv does a bunch of error checking that we're
            // not doing. regardless, this'll only be called if this PHP script couldn't open /dev/urandom due to open_basedir
            // restrictions or some such
            if (extension_loaded('mcrypt')) {
                return mcrypt_create_iv($length, MCRYPT_DEV_URANDOM);
            }
        }
        // at this point we have no choice but to use a pure-PHP CSPRNG

        // cascade entropy across multiple PHP instances by fixing the session and collecting all
        // environmental variables, including the previous session data and the current session
        // data.
        //
        // mt_rand seeds itself by looking at the PID and the time, both of which are (relatively)
        // easy to guess at. linux uses mouse clicks, keyboard timings, etc, as entropy sources, but
        // PHP isn't low level to be able to use those as sources and on a web server there's not likely
        // going to be a ton of keyboard or mouse action. web servers do have one thing that we can use
        // however, a ton of people visiting the website. obviously you don't want to base your seeding
        // soley on parameters a potential attacker sends but (1) not everything in $_SERVER is controlled
        // by the user and (2) this isn't just looking at the data sent by the current user - it's based
        // on the data sent by all users. one user requests the page and a hash of their info is saved.
        // another user visits the page and the serialization of their data is utilized along with the
        // server envirnment stuff and a hash of the previous http request data (which itself utilizes
        // a hash of the session data before that). certainly an attacker should be assumed to have
        // full control over his own http requests. he, however, is not going to have control over
        // everyone's http requests.
        static $crypto = false, $v;
        if ($crypto === false) {
            // save old session data
            $old_session_id = session_id();
            $old_use_cookies = ini_get('session.use_cookies');
            $old_session_cache_limiter = session_cache_limiter();
            $_OLD_SESSION = isset($_SESSION) ? $_SESSION : false;
            if ($old_session_id != '') {
                session_write_close();
            }

            session_id(1);
            ini_set('session.use_cookies', 0);
            session_cache_limiter('');
            session_start();

            $v = $seed = $_SESSION['seed'] = pack('H*', sha1(
                (isset($_SERVER) ? phpseclib_safe_serialize($_SERVER) : '') .
                (isset($_POST) ? phpseclib_safe_serialize($_POST) : '') .
                (isset($_GET) ? phpseclib_safe_serialize($_GET) : '') .
                (isset($_COOKIE) ? phpseclib_safe_serialize($_COOKIE) : '') .
                phpseclib_safe_serialize($GLOBALS) .
                phpseclib_safe_serialize($_SESSION) .
                phpseclib_safe_serialize($_OLD_SESSION)
            ));
            if (!isset($_SESSION['count'])) {
                $_SESSION['count'] = 0;
            }
            $_SESSION['count']++;

            session_write_close();

            // restore old session data
            if ($old_session_id != '') {
                session_id($old_session_id);
                session_start();
                ini_set('session.use_cookies', $old_use_cookies);
                session_cache_limiter($old_session_cache_limiter);
            } else {
                if ($_OLD_SESSION !== false) {
                    $_SESSION = $_OLD_SESSION;
                    unset($_OLD_SESSION);
                } else {
                    unset($_SESSION);
                }
            }

            // in SSH2 a shared secret and an exchange hash are generated through the key exchange process.
            // the IV client to server is the hash of that "nonce" with the letter A and for the encryption key it's the letter C.
            // if the hash doesn't produce enough a key or an IV that's long enough concat successive hashes of the
            // original hash and the current hash. we'll be emulating that. for more info see the following URL:
            //
            // http://tools.ietf.org/html/rfc4253#section-7.2
            //
            // see the is_string($crypto) part for an example of how to expand the keys
            $key = pack('H*', sha1($seed . 'A'));
            $iv = pack('H*', sha1($seed . 'C'));

            // ciphers are used as per the nist.gov link below. also, see this link:
            //
            // http://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator#Designs_based_on_cryptographic_primitives
            switch (true) {
                case phpseclib_resolve_include_path('Crypt/AES.php'):
                    if (!class_exists('Crypt_AES')) {
                        include_once 'AES.php';
                    }
                    $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR);
                    break;
                case phpseclib_resolve_include_path('Crypt/Twofish.php'):
                    if (!class_exists('Crypt_Twofish')) {
                        include_once 'Twofish.php';
                    }
                    $crypto = new Crypt_Twofish(CRYPT_TWOFISH_MODE_CTR);
                    break;
                case phpseclib_resolve_include_path('Crypt/Blowfish.php'):
                    if (!class_exists('Crypt_Blowfish')) {
                        include_once 'Blowfish.php';
                    }
                    $crypto = new Crypt_Blowfish(CRYPT_BLOWFISH_MODE_CTR);
                    break;
                case phpseclib_resolve_include_path('Crypt/TripleDES.php'):
                    if (!class_exists('Crypt_TripleDES')) {
                        include_once 'TripleDES.php';
                    }
                    $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
                    break;
                case phpseclib_resolve_include_path('Crypt/DES.php'):
                    if (!class_exists('Crypt_DES')) {
                        include_once 'DES.php';
                    }
                    $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
                    break;
                case phpseclib_resolve_include_path('Crypt/RC4.php'):
                    if (!class_exists('Crypt_RC4')) {
                        include_once 'RC4.php';
                    }
                    $crypto = new Crypt_RC4();
                    break;
                default:
                    user_error('crypt_random_string requires at least one symmetric cipher be loaded');
                    return false;
            }

            $crypto->setKey($key);
            $crypto->setIV($iv);
            $crypto->enableContinuousBuffer();
        }

        //return $crypto->encrypt(str_repeat("\0", $length));

        // the following is based off of ANSI X9.31:
        //
        // http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf
        //
        // OpenSSL uses that same standard for it's random numbers:
        //
        // http://www.opensource.apple.com/source/OpenSSL/OpenSSL-38/openssl/fips-1.0/rand/fips_rand.c
        // (do a search for "ANS X9.31 A.2.4")
        $result = '';
        while (strlen($result) < $length) {
            $i = $crypto->encrypt(microtime()); // strlen(microtime()) == 21
            $r = $crypto->encrypt($i ^ $v); // strlen($v) == 20
            $v = $crypto->encrypt($r ^ $i); // strlen($r) == 20
            $result.= $r;
        }
        return substr($result, 0, $length);
    }
}

if (!function_exists('phpseclib_safe_serialize')) {
    /**
     * Safely serialize variables
     *
     * If a class has a private __sleep() method it'll give a fatal error on PHP 5.2 and earlier.
     * PHP 5.3 will emit a warning.
     *
     * @param mixed $arr
     * @access public
     */
    function phpseclib_safe_serialize(&$arr)
    {
        if (is_object($arr)) {
            return '';
        }
        if (!is_array($arr)) {
            return serialize($arr);
        }
        // prevent circular array recursion
        if (isset($arr['__phpseclib_marker'])) {
            return '';
        }
        $safearr = array();
        $arr['__phpseclib_marker'] = true;
        foreach (array_keys($arr) as $key) {
            // do not recurse on the '__phpseclib_marker' key itself, for smaller memory usage
            if ($key !== '__phpseclib_marker') {
                $safearr[$key] = phpseclib_safe_serialize($arr[$key]);
            }
        }
        unset($arr['__phpseclib_marker']);
        return serialize($safearr);
    }
}

if (!function_exists('phpseclib_resolve_include_path')) {
    /**
     * Resolve filename against the include path.
     *
     * Wrapper around stream_resolve_include_path() (which was introduced in
     * PHP 5.3.2) with fallback implementation for earlier PHP versions.
     *
     * @param string $filename
     * @return string|false
     * @access public
     */
    function phpseclib_resolve_include_path($filename)
    {
        if (function_exists('stream_resolve_include_path')) {
            return stream_resolve_include_path($filename);
        }

        // handle non-relative paths
        if (file_exists($filename)) {
            return realpath($filename);
        }

        $paths = PATH_SEPARATOR == ':' ?
            preg_split('#(?<!phar):#', get_include_path()) :
            explode(PATH_SEPARATOR, get_include_path());
        foreach ($paths as $prefix) {
            // path's specified in include_path don't always end in /
            $ds = substr($prefix, -1) == DIRECTORY_SEPARATOR ? '' : DIRECTORY_SEPARATOR;
            $file = $prefix . $ds . $filename;
            if (file_exists($file)) {
                return realpath($file);
            }
        }

        return false;
    }
}