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Update Random.php

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Scott 2016-03-27 10:49:03 -04:00
parent bdb9935e35
commit 827e42222e
1 changed files with 11 additions and 58 deletions
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69
phpseclib/Crypt/Random.php
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@ -46,64 +46,17 @@ class Random
*/
static function string($length)
{
if (version_compare(PHP_VERSION, '7.0.0', '>=') || defined('RANDOM_COMPAT_READ_BUFFER')) {
try {
return \random_bytes($length);
} catch (\Throwable $e) {
// If a sufficient source of randomness is unavailable, random_bytes() will throw an
// object that implements the Throwable interface (Exception, TypeError, Error).
// We don't actually need to do anything here. The string() method should just continue
// as normal. Note, however, that if we don't have a sufficient source of randomness for
// random_bytes(), most of the other calls here will fail too, so we'll end up using
// the PHP implementation.
}
}
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
// method 1. prior to PHP 5.3 this would call rand() on windows hence the function_exists('class_alias') call.
// ie. class_alias is a function that was introduced in PHP 5.3
if (extension_loaded('mcrypt') && function_exists('class_alias')) {
return mcrypt_create_iv($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($length);
}
} else {
// method 1. the fastest
if (extension_loaded('openssl')) {
return openssl_random_pseudo_bytes($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);
}
try {
return \random_bytes($length);
} catch (\Throwable $e) {
// If a sufficient source of randomness is unavailable, random_bytes() will throw an
// object that implements the Throwable interface (Exception, TypeError, Error).
// We don't actually need to do anything here. The string() method should just continue
// as normal. Note, however, that if we don't have a sufficient source of randomness for
// random_bytes(), most of the other calls here will fail too, so we'll end up using
// the PHP implementation.
} catch (\Exception $e) {
// random_compat will throw an Exception, which in PHP 5 does not implement Throwable
}
// at this point we have no choice but to use a pure-PHP CSPRNG