diff options
Diffstat (limited to 'engine/classes/ElggCrypto.php')
| -rw-r--r-- | engine/classes/ElggCrypto.php | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/engine/classes/ElggCrypto.php b/engine/classes/ElggCrypto.php new file mode 100644 index 000000000..317d371e4 --- /dev/null +++ b/engine/classes/ElggCrypto.php @@ -0,0 +1,208 @@ +<?php +/** + * ElggCrypto + * + * @package Elgg.Core + * @subpackage Crypto + * + * @access private + */ +class ElggCrypto { + + /** + * Character set for temp passwords (no risk of embedded profanity/glyphs that look similar) + */ + const CHARS_PASSWORD = 'bcdfghjklmnpqrstvwxyz2346789'; + + /** + * Generate a string of highly randomized bytes (over the full 8-bit range). + * + * @param int $length Number of bytes needed + * @return string Random bytes + * + * @author George Argyros <argyros.george@gmail.com> + * @copyright 2012, George Argyros. All rights reserved. + * @license Modified BSD + * @link https://github.com/GeorgeArgyros/Secure-random-bytes-in-PHP/blob/master/srand.php Original + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of the <organization> nor the + * names of its contributors may be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL GEORGE ARGYROS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + public function getRandomBytes($length) { + /** + * Our primary choice for a cryptographic strong randomness function is + * openssl_random_pseudo_bytes. + */ + $SSLstr = '4'; // http://xkcd.com/221/ + if (function_exists('openssl_random_pseudo_bytes') + && (version_compare(PHP_VERSION, '5.3.4') >= 0 || substr(PHP_OS, 0, 3) !== 'WIN')) { + $SSLstr = openssl_random_pseudo_bytes($length, $strong); + if ($strong) { + return $SSLstr; + } + } + + /** + * If mcrypt extension is available then we use it to gather entropy from + * the operating system's PRNG. This is better than reading /dev/urandom + * directly since it avoids reading larger blocks of data than needed. + * Older versions of mcrypt_create_iv may be broken or take too much time + * to finish so we only use this function with PHP 5.3.7 and above. + * @see https://bugs.php.net/bug.php?id=55169 + */ + if (function_exists('mcrypt_create_iv') + && (version_compare(PHP_VERSION, '5.3.7') >= 0 || substr(PHP_OS, 0, 3) !== 'WIN')) { + $str = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM); + if ($str !== false) { + return $str; + } + } + + /** + * No build-in crypto randomness function found. We collect any entropy + * available in the PHP core PRNGs along with some filesystem info and memory + * stats. To make this data cryptographically strong we add data either from + * /dev/urandom or if its unavailable, we gather entropy by measuring the + * time needed to compute a number of SHA-1 hashes. + */ + $str = ''; + $bits_per_round = 2; // bits of entropy collected in each clock drift round + $msec_per_round = 400; // expected running time of each round in microseconds + $hash_len = 20; // SHA-1 Hash length + $total = $length; // total bytes of entropy to collect + + $handle = @fopen('/dev/urandom', 'rb'); + if ($handle && function_exists('stream_set_read_buffer')) { + @stream_set_read_buffer($handle, 0); + } + + do { + $bytes = ($total > $hash_len) ? $hash_len : $total; + $total -= $bytes; + + //collect any entropy available from the PHP system and filesystem + $entropy = rand() . uniqid(mt_rand(), true) . $SSLstr; + $entropy .= implode('', @fstat(@fopen(__FILE__, 'r'))); + $entropy .= memory_get_usage() . getmypid(); + $entropy .= serialize($_ENV) . serialize($_SERVER); + if (function_exists('posix_times')) { + $entropy .= serialize(posix_times()); + } + if (function_exists('zend_thread_id')) { + $entropy .= zend_thread_id(); + } + + if ($handle) { + $entropy .= @fread($handle, $bytes); + } else { + // Measure the time that the operations will take on average + for ($i = 0; $i < 3; $i++) { + $c1 = microtime(true); + $var = sha1(mt_rand()); + for ($j = 0; $j < 50; $j++) { + $var = sha1($var); + } + $c2 = microtime(true); + $entropy .= $c1 . $c2; + } + + // Based on the above measurement determine the total rounds + // in order to bound the total running time. + $rounds = (int) ($msec_per_round * 50 / (int) (($c2 - $c1) * 1000000)); + + // Take the additional measurements. On average we can expect + // at least $bits_per_round bits of entropy from each measurement. + $iter = $bytes * (int) (ceil(8 / $bits_per_round)); + + for ($i = 0; $i < $iter; $i++) { + $c1 = microtime(); + $var = sha1(mt_rand()); + for ($j = 0; $j < $rounds; $j++) { + $var = sha1($var); + } + $c2 = microtime(); + $entropy .= $c1 . $c2; + } + } + + // We assume sha1 is a deterministic extractor for the $entropy variable. + $str .= sha1($entropy, true); + + } while ($length > strlen($str)); + + if ($handle) { + @fclose($handle); + } + + return substr($str, 0, $length); + } + + /** + * Generate a random string of specified length. + * + * Uses supplied character list for generating the new string. + * If no character list provided - uses Base64 URL character set. + * + * @param int $length Desired length of the string + * @param string|null $chars Characters to be chosen from randomly. If not given, the Base64 URL + * charset will be used. + * + * @return string The random string + * + * @throws InvalidArgumentException + * + * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com) + * @license http://framework.zend.com/license/new-bsd New BSD License + * + * @see https://github.com/zendframework/zf2/blob/master/library/Zend/Math/Rand.php#L179 + */ + public static function getRandomString($length, $chars = null) { + if ($length < 1) { + throw new InvalidArgumentException('Length should be >= 1'); + } + + if (empty($chars)) { + $numBytes = ceil($length * 0.75); + $bytes = self::getRandomBytes($numBytes); + $string = substr(rtrim(base64_encode($bytes), '='), 0, $length); + + // Base64 URL + return strtr($string, '+/', '-_'); + } + + $listLen = strlen($chars); + + if ($listLen == 1) { + return str_repeat($chars, $length); + } + + $bytes = self::getRandomBytes($length); + $pos = 0; + $result = ''; + for ($i = 0; $i < $length; $i++) { + $pos = ($pos + ord($bytes[$i])) % $listLen; + $result .= $chars[$pos]; + } + + return $result; + } +} |