Chris@0: <?php
Chris@0: /**
Chris@17:  * Random_* Compatibility Library
Chris@0:  * for using the new PHP 7 random_* API in PHP 5 projects
Chris@17:  *
Chris@0:  * The MIT License (MIT)
Chris@17:  *
Chris@16:  * Copyright (c) 2015 - 2018 Paragon Initiative Enterprises
Chris@17:  *
Chris@0:  * Permission is hereby granted, free of charge, to any person obtaining a copy
Chris@0:  * of this software and associated documentation files (the "Software"), to deal
Chris@0:  * in the Software without restriction, including without limitation the rights
Chris@0:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
Chris@0:  * copies of the Software, and to permit persons to whom the Software is
Chris@0:  * furnished to do so, subject to the following conditions:
Chris@17:  *
Chris@0:  * The above copyright notice and this permission notice shall be included in
Chris@0:  * all copies or substantial portions of the Software.
Chris@17:  *
Chris@0:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Chris@0:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Chris@0:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
Chris@0:  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Chris@0:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
Chris@0:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
Chris@0:  * SOFTWARE.
Chris@0:  */
Chris@0: 
Chris@0: if (!is_callable('random_bytes')) {
Chris@0:     /**
Chris@0:      * Windows with PHP < 5.3.0 will not have the function
Chris@0:      * openssl_random_pseudo_bytes() available, so let's use
Chris@0:      * CAPICOM to work around this deficiency.
Chris@0:      *
Chris@0:      * @param int $bytes
Chris@0:      *
Chris@0:      * @throws Exception
Chris@0:      *
Chris@0:      * @return string
Chris@0:      */
Chris@0:     function random_bytes($bytes)
Chris@0:     {
Chris@0:         try {
Chris@16:             /** @var int $bytes */
Chris@0:             $bytes = RandomCompat_intval($bytes);
Chris@0:         } catch (TypeError $ex) {
Chris@0:             throw new TypeError(
Chris@0:                 'random_bytes(): $bytes must be an integer'
Chris@0:             );
Chris@0:         }
Chris@0: 
Chris@0:         if ($bytes < 1) {
Chris@0:             throw new Error(
Chris@0:                 'Length must be greater than 0'
Chris@0:             );
Chris@0:         }
Chris@0: 
Chris@16:         /** @var string $buf */
Chris@0:         $buf = '';
Chris@0:         if (!class_exists('COM')) {
Chris@0:             throw new Error(
Chris@0:                 'COM does not exist'
Chris@0:             );
Chris@0:         }
Chris@16:         /** @var COM $util */
Chris@0:         $util = new COM('CAPICOM.Utilities.1');
Chris@0:         $execCount = 0;
Chris@0: 
Chris@0:         /**
Chris@0:          * Let's not let it loop forever. If we run N times and fail to
Chris@0:          * get N bytes of random data, then CAPICOM has failed us.
Chris@0:          */
Chris@0:         do {
Chris@16:             $buf .= base64_decode((string) $util->GetRandom($bytes, 0));
Chris@0:             if (RandomCompat_strlen($buf) >= $bytes) {
Chris@0:                 /**
Chris@0:                  * Return our random entropy buffer here:
Chris@0:                  */
Chris@16:                 return (string) RandomCompat_substr($buf, 0, $bytes);
Chris@0:             }
Chris@0:             ++$execCount;
Chris@0:         } while ($execCount < $bytes);
Chris@0: 
Chris@0:         /**
Chris@0:          * If we reach here, PHP has failed us.
Chris@0:          */
Chris@0:         throw new Exception(
Chris@0:             'Could not gather sufficient random data'
Chris@0:         );
Chris@0:     }
Chris@17: }