PHP Classes

File: lib/random.php

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  Classes of Scott Arciszewski   random_compat   lib/random.php   Download  
File: lib/random.php
Role: Example script
Content type: text/plain
Description: Example script
Class: random_compat
Provide random_bytes and random_int functions
Author: By
Last change:
Date: 6 years ago
Size: 7,687 bytes
 

Contents

Class file image Download
<?php
/**
 * Random_* Compatibility Library
 * for using the new PHP 7 random_* API in PHP 5 projects
 *
 * @version 2.0.10
 * @released 2017-03-13
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises
 *
 * 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.
 */

if (!defined('PHP_VERSION_ID')) {
   
// This constant was introduced in PHP 5.2.7
   
$RandomCompatversion = array_map('intval', explode('.', PHP_VERSION));
   
define(
       
'PHP_VERSION_ID',
       
$RandomCompatversion[0] * 10000
       
+ $RandomCompatversion[1] * 100
       
+ $RandomCompatversion[2]
    );
   
$RandomCompatversion = null;
}

/**
 * PHP 7.0.0 and newer have these functions natively.
 */
if (PHP_VERSION_ID >= 70000) {
    return;
}

if (!
defined('RANDOM_COMPAT_READ_BUFFER')) {
   
define('RANDOM_COMPAT_READ_BUFFER', 8);
}

$RandomCompatDIR = dirname(__FILE__);

require_once
$RandomCompatDIR . '/byte_safe_strings.php';
require_once
$RandomCompatDIR . '/cast_to_int.php';
require_once
$RandomCompatDIR . '/error_polyfill.php';

if (!
is_callable('random_bytes')) {
   
/**
     * PHP 5.2.0 - 5.6.x way to implement random_bytes()
     *
     * We use conditional statements here to define the function in accordance
     * to the operating environment. It's a micro-optimization.
     *
     * In order of preference:
     * 1. Use libsodium if available.
     * 2. fread() /dev/urandom if available (never on Windows)
     * 3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
     * 4. COM('CAPICOM.Utilities.1')->GetRandom()
     *
     * See RATIONALE.md for our reasoning behind this particular order
     */
   
if (extension_loaded('libsodium')) {
       
// See random_bytes_libsodium.php
       
if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
            require_once
$RandomCompatDIR . '/random_bytes_libsodium.php';
        } elseif (
method_exists('Sodium', 'randombytes_buf')) {
            require_once
$RandomCompatDIR . '/random_bytes_libsodium_legacy.php';
        }
    }

   
/**
     * Reading directly from /dev/urandom:
     */
   
if (DIRECTORY_SEPARATOR === '/') {
       
// DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
        // way to exclude Windows.
       
$RandomCompatUrandom = true;
       
$RandomCompat_basedir = ini_get('open_basedir');

        if (!empty(
$RandomCompat_basedir)) {
           
$RandomCompat_open_basedir = explode(
               
PATH_SEPARATOR,
               
strtolower($RandomCompat_basedir)
            );
           
$RandomCompatUrandom = (array() !== array_intersect(
                array(
'/dev', '/dev/', '/dev/urandom'),
               
$RandomCompat_open_basedir
           
));
           
$RandomCompat_open_basedir = null;
        }

        if (
            !
is_callable('random_bytes')
            &&
           
$RandomCompatUrandom
           
&&
            @
is_readable('/dev/urandom')
        ) {
           
// Error suppression on is_readable() in case of an open_basedir
            // or safe_mode failure. All we care about is whether or not we
            // can read it at this point. If the PHP environment is going to
            // panic over trying to see if the file can be read in the first
            // place, that is not helpful to us here.

            // See random_bytes_dev_urandom.php
           
require_once $RandomCompatDIR . '/random_bytes_dev_urandom.php';
        }
       
// Unset variables after use
       
$RandomCompat_basedir = null;
    } else {
       
$RandomCompatUrandom = false;
    }

   
/**
     * mcrypt_create_iv()
     *
     * We only want to use mcypt_create_iv() if:
     *
     * - random_bytes() hasn't already been defined
     * - the mcrypt extensions is loaded
     * - One of these two conditions is true:
     * - We're on Windows (DIRECTORY_SEPARATOR !== '/')
     * - We're not on Windows and /dev/urandom is readabale
     * (i.e. we're not in a chroot jail)
     * - Special case:
     * - If we're not on Windows, but the PHP version is between
     * 5.6.10 and 5.6.12, we don't want to use mcrypt. It will
     * hang indefinitely. This is bad.
     * - If we're on Windows, we want to use PHP >= 5.3.7 or else
     * we get insufficient entropy errors.
     */
   
if (
        !
is_callable('random_bytes')
        &&
       
// Windows on PHP < 5.3.7 is broken, but non-Windows is not known to be.
       
(DIRECTORY_SEPARATOR === '/' || PHP_VERSION_ID >= 50307)
        &&
       
// Prevent this code from hanging indefinitely on non-Windows;
        // see https://bugs.php.net/bug.php?id=69833
       
(
           
DIRECTORY_SEPARATOR !== '/' ||
            (
PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
        )
        &&
       
extension_loaded('mcrypt')
    ) {
       
// See random_bytes_mcrypt.php
       
require_once $RandomCompatDIR . '/random_bytes_mcrypt.php';
    }
   
$RandomCompatUrandom = null;

   
/**
     * This is a Windows-specific fallback, for when the mcrypt extension
     * isn't loaded.
     */
   
if (
        !
is_callable('random_bytes')
        &&
       
extension_loaded('com_dotnet')
        &&
       
class_exists('COM')
    ) {
       
$RandomCompat_disabled_classes = preg_split(
           
'#\s*,\s*#',
           
strtolower(ini_get('disable_classes'))
        );

        if (!
in_array('com', $RandomCompat_disabled_classes)) {
            try {
               
$RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
                if (
method_exists($RandomCompatCOMtest, 'GetRandom')) {
                   
// See random_bytes_com_dotnet.php
                   
require_once $RandomCompatDIR . '/random_bytes_com_dotnet.php';
                }
            } catch (
com_exception $e) {
               
// Don't try to use it.
           
}
        }
       
$RandomCompat_disabled_classes = null;
       
$RandomCompatCOMtest = null;
    }

   
/**
     * throw new Exception
     */
   
if (!is_callable('random_bytes')) {
       
/**
         * We don't have any more options, so let's throw an exception right now
         * and hope the developer won't let it fail silently.
         *
         * @param mixed $length
         * @return void
         * @throws Exception
         */
       
function random_bytes($length)
        {
            unset(
$length); // Suppress "variable not used" warnings.
           
throw new Exception(
               
'There is no suitable CSPRNG installed on your system'
           
);
        }
    }
}

if (!
is_callable('random_int')) {
    require_once
$RandomCompatDIR . '/random_int.php';
}

$RandomCompatDIR = null;