<?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; | |
} | |
} |