Online PHP editor | refs for VJGCb

<?php /** * Random_* Compatibility Library * for using the new PHP 7 random_* API in PHP 5 projects * * The MIT License (MIT) * * Copyright (c) 2015 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('RANDOM_COMPAT_READ_BUFFER')) { define('RANDOM_COMPAT_READ_BUFFER', 8); } if (!function_exists('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. fread() /dev/urandom if available * 2. mcrypt_create_iv($bytes, MCRYPT_CREATE_IV) * 3. COM('CAPICOM.Utilities.1')->GetRandom() * 4. openssl_random_pseudo_bytes() * * See ERRATA.md for our reasoning behind this particular order */ if (!ini_get('open_basedir') && is_readable('/dev/urandom')) { /** * Unless open_basedir is enabled, use /dev/urandom for * random numbers in accordance with best practices * * Why we use /dev/urandom and not /dev/random * @ref http://sockpuppet.org/blog/2014/02/25/safely-generate-random-numbers * * @param int $bytes * * @throws Exception * * @return string */ function random_bytes($bytes) { static $fp = null; /** * This block should only be run once */ if (empty($fp)) { /** * We use /dev/urandom if it is a char device. * We never fall back to /dev/random */ $fp = fopen('/dev/urandom', 'rb'); if (!empty($fp)) { $st = fstat($fp); if (($st['mode'] & 020000) === 0) { fclose($fp); $fp = false; } } /** * stream_set_read_buffer() does not exist in HHVM * * If we don't set the stream's read buffer to 0, PHP will * internally buffer 8192 bytes, which can waste entropy * * stream_set_read_buffer returns 0 on success */ if (!empty($fp) && function_exists('stream_set_read_buffer')) { stream_set_read_buffer($fp, RANDOM_COMPAT_READ_BUFFER); } } /** * This if() block only runs if we managed to open a file handle * * It does not belong in an else {} block, because the above * if (empty($fp)) line is logic that should only be run once per * page load. */ if (!empty($fp)) { $remaining = $bytes; $buf = ''; /** * We use fread() in a loop to protect against partial reads */ do { $read = fread($fp, $remaining); if ($read === false) { /** * We cannot safely read from the file. Exit the * do-while loop and trigger the exception condition */ $buf = false; break; } /** * Decrease the number of bytes returned from remaining */ $remaining -= RandomCompat_strlen($read); $buf .= $read; } while ($remaining > 0); /** * Is our result valid? */ if ($buf !== false) { if (RandomCompat_strlen($buf) === $bytes) { /** * Return our random entropy buffer here: */ return $buf; } } } /** * If we reach here, PHP has failed us. */ throw new Exception( 'PHP failed to generate random data.' ); } } elseif (function_exists('mcrypt_create_iv') && version_compare(PHP_VERSION, '5.3.7') >= 0) { /** * Powered by ext/mcrypt (and thankfully NOT libmcrypt) * * @ref https://bugs.php.net/bug.php?id=55169 * @ref https://github.com/php/php-src/blob/c568ffe5171d942161fc8dda066bce844bdef676/ext/mcrypt/mcrypt.c#L1321-L1386 * * @param int $bytes * * @throws Exception * * @return string */ function random_bytes($bytes) { if (!is_int($bytes)) { throw new Exception( 'Length must be an integer' ); } if ($bytes < 1) { throw new Exception( 'Length must be greater than 0' ); } $buf = mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM); if ($buf !== false) { if (RandomCompat_strlen($buf) === $bytes) { /** * Return our random entropy buffer here: */ return $buf; } } /** * If we reach here, PHP has failed us. */ throw new Exception( 'PHP failed to generate random data.' ); } } elseif (extension_loaded('com_dotnet')) { /** * Windows with PHP < 5.3.0 will not have the function * openssl_random_pseudo_bytes() available, so let's use * CAPICOM to work around this deficiency. * * @param int $bytes * * @throws Exception * * @return string */ function random_bytes($bytes) { $buf = ''; $util = new COM('CAPICOM.Utilities.1'); $execCount = 0; /** * Let's not let it loop forever. If we run N times and fail to * get N bytes of random data, then CAPICOM has failed us. */ do { $buf .= base64_decode($util->GetRandom($bytes, 0)); if (RandomCompat_strlen($buf) >= $bytes) { /** * Return our random entropy buffer here: */ return RandomCompat_substr($buf, 0, $bytes); } ++$execCount; } while ($execCount < $bytes); /** * If we reach here, PHP has failed us. */ throw new Exception( 'PHP failed to generate random data.' ); } } elseif (function_exists('openssl_random_pseudo_bytes')) { /** * Since openssl_random_pseudo_bytes() uses openssl's * RAND_pseudo_bytes() API, which has been marked as deprecated by the * OpenSSL team, this is our last resort before failure. * * @ref https://www.openssl.org/docs/crypto/RAND_bytes.html * * @param int $bytes * * @throws Exception * * @return string */ function random_bytes($bytes) { $secure = true; /** * $secure is passed by reference. If it's set to false, fail. Note * that this will only return false if this function fails to return * any data. * * @ref https://github.com/paragonie/random_compat/issues/6#issuecomment-119564973 */ $buf = openssl_random_pseudo_bytes($bytes, $secure); if ($buf !== false && $secure) { if (RandomCompat_strlen($buf) === $bytes) { return $buf; } } /** * If we reach here, PHP has failed us. */ throw new Exception( 'PHP failed to generate random data.' ); } } else { /** * 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. */ throw new Exception( 'There is no suitable CSPRNG installed on your system' ); } } if (!function_exists('random_int')) { /** * Fetch a random integer between $min and $max inclusive * * @param int $min * @param int $max * * @throws Exception * * @return int */ function random_int($min, $max) { /** * Type and input logic checks */ if (!is_int($min)) { throw new Exception( 'random_int(): $min must be an integer' ); } if (!is_int($max)) { throw new Exception( 'random_int(): $max must be an integer' ); } if ($min > $max) { throw new Exception( 'Minimum value must be less than or equal to the maximum value' ); } if ($max === $min) { return $min; } /** * Initialize variables to 0 * * We want to store: * $bytes => the number of random bytes we need * $mask => an integer bitmask (for use with the &) operator * so we can minimize the number of discards */ $attempts = $bits = $bytes = $mask = $valueShift = 0; /** * At this point, $range is a positive number greater than 0. It might * overflow, however, if $max - $min > PHP_INT_MAX. PHP will cast it to * a float and we will lose some precision. */ $range = $max - $min; /** * Test for integer overflow: */ if (!is_int($range)) { /** * Still safely calculate wider ranges. * Provided by @CodesInChaos, @oittaa * * @ref https://gist.github.com/CodesInChaos/03f9ea0b58e8b2b8d435 * * We use ~0 as a mask in this case because it generates all 1s * * @ref https://eval.in/400356 (32-bit) * @ref http://3v4l.org/XX9r5 (64-bit) */ $bytes = PHP_INT_SIZE; $mask = ~0; } else { /** * $bits is effectively ceil(log($range, 2)) without dealing with * type juggling */ while ($range > 0) { if ($bits % 8 === 0) { ++$bytes; } ++$bits; $range >>= 1; $mask = $mask << 1 | 1; } $valueShift = $min; } /** * Now that we have our parameters set up, let's begin generating * random integers until one falls between $min and $max */ do { /** * The rejection probability is at most 0.5, so this corresponds * to a failure probability of 2^-128 for a working RNG */ if ($attempts > 128) { throw new Exception( 'random_int: RNG is broken - too many rejections' ); } /** * Let's grab the necessary number of random bytes */ $randomByteString = random_bytes($bytes); if ($randomByteString === false) { throw new Exception( 'Random number generator failure' ); } /** * Let's turn $randomByteString into an integer * * This uses bitwise operators (<< and |) to build an integer * out of the values extracted from ord() * * Example: [9F] | [6D] | [32] | [0C] => * 159 + 27904 + 3276800 + 201326592 => * 204631455 */ $val = 0; for ($i = 0; $i < $bytes; ++$i) { $val |= ord($randomByteString[$i]) << ($i * 8); } /** * Apply mask */ $val &= $mask; $val += $valueShift; ++$attempts; /** * If $val overflows to a floating point number, * ... or is larger than $max, * ... or smaller than $int, * then try again. */ } while (!is_int($val) || $val > $max || $val < $min); return (int) $val; } } if (!function_exists('RandomCompat_strlen')) { if (function_exists('mb_strlen')) { /** * strlen() implementation that isn't brittle to mbstring.func_overload * * This version uses mb_strlen() in '8bit' mode to treat strings as raw * binary rather than UTF-8, ISO-8859-1, etc * * @param string $binary_string * * @throws InvalidArgumentException * * @return int */ function RandomCompat_strlen($binary_string) { if (!is_string($binary_string)) { throw new InvalidArgumentException( 'RandomCompat_strlen() expects a string' ); } return mb_strlen($binary_string, '8bit'); } } else { /** * strlen() implementation that isn't brittle to mbstring.func_overload * * This version just used the default strlen() * * @param string $binary_string * * @throws InvalidArgumentException * * @return int */ function RandomCompat_strlen($binary_string) { if (!is_string($binary_string)) { throw new InvalidArgumentException( 'RandomCompat_strlen() expects a string' ); } return strlen($binary_string); } } } if (!function_exists('RandomCompat_substr')) { if (function_exists('mb_substr')) { /** * substr() implementation that isn't brittle to mbstring.func_overload * * This version uses mb_substr() in '8bit' mode to treat strings as raw * binary rather than UTF-8, ISO-8859-1, etc * * @param string $binary_string * @param int $start * @param int $length (optional) * * @throws InvalidArgumentException * * @return string */ function RandomCompat_substr($binary_string, $start, $length = null) { if (!is_string($binary_string)) { throw new InvalidArgumentException( 'RandomCompat_substr(): First argument should be a string' ); } if (!is_int($start)) { throw new InvalidArgumentException( 'RandomCompat_substr(): Second argument should be an integer' ); } if ($length === null) { /** * mb_substr($str, 0, NULL, '8bit') returns an empty string on * PHP 5.3, so we have to find the length ourselves. */ $length = RandomCompat_strlen($length) - $start; } elseif (!is_int($length)) { throw new InvalidArgumentException( 'RandomCompat_substr(): Third argument should be an integer, or omitted' ); } return mb_substr($binary_string, $start, $length, '8bit'); } } else { /** * substr() implementation that isn't brittle to mbstring.func_overload * * This version just uses the default substr() * * @param string $binary_string * @param int $start * @param int $length (optional) * * @throws InvalidArgumentException * * @return string */ function RandomCompat_substr($binary_string, $start, $length = null) { if (!is_string($binary_string)) { throw new InvalidArgumentException( 'RandomCompat_substr(): First argument should be a string' ); } if (!is_int($start)) { throw new InvalidArgumentException( 'RandomCompat_substr(): Second argument should be an integer' ); } if ($length !== null) { if (!is_int($length)) { throw new InvalidArgumentException( 'RandomCompat_substr(): Third argument should be an integer, or omitted' ); } return substr($binary_string, $start, $length); } return substr($binary_string, $start); } } } var_dump([ random_int(-PHP_INT_MAX, PHP_INT_MAX), random_int(-2147483648, 2147483647) ]);