openstackid-resources/app/Models/Utils/RandomGenerator.php

85 lines
3.0 KiB
PHP

<?php namespace models\utils;
/**
* Copyright 2017 OpenStack Foundation
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
**/
use Exception;
/**
* Class RandomGenerator
* @package models\utils
*/
final class RandomGenerator {
/**
* Note: Returned values are not guaranteed to be crypto-safe,
* depending on the used retrieval method.
*
* @return string Returns a random series of bytes
*/
public function generateEntropy() {
$isWin = preg_match('/WIN/', PHP_OS);
// TODO Fails with "Could not gather sufficient random data" on IIS, temporarily disabled on windows
if(!$isWin) {
if(function_exists('mcrypt_create_iv')) {
$e = mcrypt_create_iv(64, MCRYPT_DEV_URANDOM);
if($e !== false) return $e;
}
}
// Fall back to SSL methods - may slow down execution by a few ms
if (function_exists('openssl_random_pseudo_bytes')) {
$e = openssl_random_pseudo_bytes(64, $strong);
// Only return if strong algorithm was used
if($strong) return $e;
}
// Read from the unix random number generator
if(!$isWin && !ini_get('open_basedir') && is_readable('/dev/urandom') && ($h = fopen('/dev/urandom', 'rb'))) {
$e = fread($h, 64);
fclose($h);
return $e;
}
// Warning: Both methods below are considered weak
// try to read from the windows RNG
if($isWin && class_exists('COM')) {
try {
$comObj = new COM('CAPICOM.Utilities.1');
if(is_callable(array($comObj,'GetRandom'))) {
return base64_decode($comObj->GetRandom(64, 0));
}
} catch (Exception $ex) {
}
}
// Fallback to good old mt_rand()
return uniqid(mt_rand(), true);
}
/**
* Generates a random token that can be used for session IDs, CSRF tokens etc., based on
* hash algorithms.
*
* If you are using it as a password equivalent (e.g. autologin token) do NOT store it
* in the database as a plain text but encrypt it with Member::encryptWithUserSettings.
*
* @param String $algorithm Any identifier listed in hash_algos() (Default: whirlpool)
*
* @return String Returned length will depend on the used $algorithm
*/
public function randomToken($algorithm = 'whirlpool') {
return hash($algorithm, $this->generateEntropy());
}
}