Chris@0: <?php
Chris@0: /**
Chris@0:  * Random_* Compatibility Library
Chris@0:  * for using the new PHP 7 random_* API in PHP 5 projects
Chris@0:  *
Chris@16:  * @version 2.0.17
Chris@16:  * @released 2018-07-04
Chris@0:  *
Chris@0:  * The MIT License (MIT)
Chris@0:  *
Chris@16:  * Copyright (c) 2015 - 2018 Paragon Initiative Enterprises
Chris@0:  *
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@0:  *
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@0:  *
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 (!defined('PHP_VERSION_ID')) {
Chris@0:     // This constant was introduced in PHP 5.2.7
Chris@0:     $RandomCompatversion = array_map('intval', explode('.', PHP_VERSION));
Chris@0:     define(
Chris@0:         'PHP_VERSION_ID',
Chris@0:         $RandomCompatversion[0] * 10000
Chris@0:         + $RandomCompatversion[1] * 100
Chris@0:         + $RandomCompatversion[2]
Chris@0:     );
Chris@0:     $RandomCompatversion = null;
Chris@0: }
Chris@0: 
Chris@0: /**
Chris@0:  * PHP 7.0.0 and newer have these functions natively.
Chris@0:  */
Chris@0: if (PHP_VERSION_ID >= 70000) {
Chris@0:     return;
Chris@0: }
Chris@0: 
Chris@0: if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
Chris@0:     define('RANDOM_COMPAT_READ_BUFFER', 8);
Chris@0: }
Chris@0: 
Chris@0: $RandomCompatDIR = dirname(__FILE__);
Chris@0: 
Chris@16: require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'byte_safe_strings.php';
Chris@16: require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'cast_to_int.php';
Chris@16: require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'error_polyfill.php';
Chris@0: 
Chris@0: if (!is_callable('random_bytes')) {
Chris@0:     /**
Chris@0:      * PHP 5.2.0 - 5.6.x way to implement random_bytes()
Chris@0:      *
Chris@0:      * We use conditional statements here to define the function in accordance
Chris@0:      * to the operating environment. It's a micro-optimization.
Chris@0:      *
Chris@0:      * In order of preference:
Chris@0:      *   1. Use libsodium if available.
Chris@0:      *   2. fread() /dev/urandom if available (never on Windows)
Chris@0:      *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
Chris@0:      *   4. COM('CAPICOM.Utilities.1')->GetRandom()
Chris@0:      *
Chris@0:      * See RATIONALE.md for our reasoning behind this particular order
Chris@0:      */
Chris@0:     if (extension_loaded('libsodium')) {
Chris@0:         // See random_bytes_libsodium.php
Chris@0:         if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
Chris@16:             require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'random_bytes_libsodium.php';
Chris@0:         } elseif (method_exists('Sodium', 'randombytes_buf')) {
Chris@16:             require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'random_bytes_libsodium_legacy.php';
Chris@0:         }
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Reading directly from /dev/urandom:
Chris@0:      */
Chris@0:     if (DIRECTORY_SEPARATOR === '/') {
Chris@0:         // DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
Chris@0:         // way to exclude Windows.
Chris@0:         $RandomCompatUrandom = true;
Chris@0:         $RandomCompat_basedir = ini_get('open_basedir');
Chris@0: 
Chris@0:         if (!empty($RandomCompat_basedir)) {
Chris@0:             $RandomCompat_open_basedir = explode(
Chris@0:                 PATH_SEPARATOR,
Chris@0:                 strtolower($RandomCompat_basedir)
Chris@0:             );
Chris@0:             $RandomCompatUrandom = (array() !== array_intersect(
Chris@0:                 array('/dev', '/dev/', '/dev/urandom'),
Chris@0:                 $RandomCompat_open_basedir
Chris@0:             ));
Chris@0:             $RandomCompat_open_basedir = null;
Chris@0:         }
Chris@0: 
Chris@0:         if (
Chris@0:             !is_callable('random_bytes')
Chris@0:             &&
Chris@0:             $RandomCompatUrandom
Chris@0:             &&
Chris@0:             @is_readable('/dev/urandom')
Chris@0:         ) {
Chris@0:             // Error suppression on is_readable() in case of an open_basedir
Chris@0:             // or safe_mode failure. All we care about is whether or not we
Chris@0:             // can read it at this point. If the PHP environment is going to
Chris@0:             // panic over trying to see if the file can be read in the first
Chris@0:             // place, that is not helpful to us here.
Chris@0: 
Chris@0:             // See random_bytes_dev_urandom.php
Chris@16:             require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'random_bytes_dev_urandom.php';
Chris@0:         }
Chris@0:         // Unset variables after use
Chris@0:         $RandomCompat_basedir = null;
Chris@0:     } else {
Chris@0:         $RandomCompatUrandom = false;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * mcrypt_create_iv()
Chris@0:      *
Chris@0:      * We only want to use mcypt_create_iv() if:
Chris@0:      *
Chris@0:      * - random_bytes() hasn't already been defined
Chris@0:      * - the mcrypt extensions is loaded
Chris@0:      * - One of these two conditions is true:
Chris@0:      *   - We're on Windows (DIRECTORY_SEPARATOR !== '/')
Chris@0:      *   - We're not on Windows and /dev/urandom is readabale
Chris@0:      *     (i.e. we're not in a chroot jail)
Chris@0:      * - Special case:
Chris@0:      *   - If we're not on Windows, but the PHP version is between
Chris@0:      *     5.6.10 and 5.6.12, we don't want to use mcrypt. It will
Chris@0:      *     hang indefinitely. This is bad.
Chris@0:      *   - If we're on Windows, we want to use PHP >= 5.3.7 or else
Chris@0:      *     we get insufficient entropy errors.
Chris@0:      */
Chris@0:     if (
Chris@0:         !is_callable('random_bytes')
Chris@0:         &&
Chris@0:         // Windows on PHP < 5.3.7 is broken, but non-Windows is not known to be.
Chris@0:         (DIRECTORY_SEPARATOR === '/' || PHP_VERSION_ID >= 50307)
Chris@0:         &&
Chris@0:         // Prevent this code from hanging indefinitely on non-Windows;
Chris@0:         // see https://bugs.php.net/bug.php?id=69833
Chris@0:         (
Chris@0:             DIRECTORY_SEPARATOR !== '/' ||
Chris@0:             (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
Chris@0:         )
Chris@0:         &&
Chris@0:         extension_loaded('mcrypt')
Chris@0:     ) {
Chris@0:         // See random_bytes_mcrypt.php
Chris@16:         require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'random_bytes_mcrypt.php';
Chris@0:     }
Chris@0:     $RandomCompatUrandom = null;
Chris@0: 
Chris@0:     /**
Chris@0:      * This is a Windows-specific fallback, for when the mcrypt extension
Chris@0:      * isn't loaded.
Chris@0:      */
Chris@0:     if (
Chris@0:         !is_callable('random_bytes')
Chris@0:         &&
Chris@0:         extension_loaded('com_dotnet')
Chris@0:         &&
Chris@0:         class_exists('COM')
Chris@0:     ) {
Chris@0:         $RandomCompat_disabled_classes = preg_split(
Chris@0:             '#\s*,\s*#',
Chris@0:             strtolower(ini_get('disable_classes'))
Chris@0:         );
Chris@0: 
Chris@0:         if (!in_array('com', $RandomCompat_disabled_classes)) {
Chris@0:             try {
Chris@0:                 $RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
Chris@0:                 if (method_exists($RandomCompatCOMtest, 'GetRandom')) {
Chris@0:                     // See random_bytes_com_dotnet.php
Chris@16:                     require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'random_bytes_com_dotnet.php';
Chris@0:                 }
Chris@0:             } catch (com_exception $e) {
Chris@0:                 // Don't try to use it.
Chris@0:             }
Chris@0:         }
Chris@0:         $RandomCompat_disabled_classes = null;
Chris@0:         $RandomCompatCOMtest = null;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * throw new Exception
Chris@0:      */
Chris@0:     if (!is_callable('random_bytes')) {
Chris@0:         /**
Chris@0:          * We don't have any more options, so let's throw an exception right now
Chris@0:          * and hope the developer won't let it fail silently.
Chris@0:          *
Chris@0:          * @param mixed $length
Chris@16:          * @psalm-suppress InvalidReturnType
Chris@0:          * @throws Exception
Chris@13:          * @return string
Chris@0:          */
Chris@0:         function random_bytes($length)
Chris@0:         {
Chris@0:             unset($length); // Suppress "variable not used" warnings.
Chris@0:             throw new Exception(
Chris@0:                 'There is no suitable CSPRNG installed on your system'
Chris@0:             );
Chris@13:             return '';
Chris@0:         }
Chris@0:     }
Chris@0: }
Chris@0: 
Chris@0: if (!is_callable('random_int')) {
Chris@16:     require_once $RandomCompatDIR . DIRECTORY_SEPARATOR . 'random_int.php';
Chris@0: }
Chris@0: 
Chris@0: $RandomCompatDIR = null;