Crypt.php in Service Container 7
Same filename and directory in other branches
Contains \Drupal\Component\Utility\Crypt.
Namespace
Drupal\Component\UtilityFile
lib/Drupal/Component/Utility/Crypt.phpView source
<?php
/**
* @file
* Contains \Drupal\Component\Utility\Crypt.
*/
namespace Drupal\Component\Utility;
/**
* Utility class for cryptographically-secure string handling routines.
*
* @ingroup utility
*/
class Crypt {
/**
* Returns a string of highly randomized bytes (over the full 8-bit range).
*
* This function is better than simply calling mt_rand() or any other built-in
* PHP function because it can return a long string of bytes (compared to < 4
* bytes normally from mt_rand()) and uses the best available pseudo-random
* source.
*
* @param int $count
* The number of characters (bytes) to return in the string.
*
* @return string
* A randomly generated string.
*/
public static function randomBytes($count) {
// $random_state does not use drupal_static as it stores random bytes.
static $random_state, $bytes;
$missing_bytes = $count - strlen($bytes);
if ($missing_bytes > 0) {
// openssl_random_pseudo_bytes() will find entropy in a system-dependent
// way.
if (function_exists('openssl_random_pseudo_bytes')) {
$bytes .= openssl_random_pseudo_bytes($missing_bytes);
}
elseif (function_exists('mcrypt_create_iv') && defined('MCRYPT_DEV_URANDOM')) {
$bytes .= mcrypt_create_iv($count, MCRYPT_DEV_URANDOM);
}
elseif ($fh = @fopen('/dev/urandom', 'rb')) {
// PHP only performs buffered reads, so in reality it will always read
// at least 4096 bytes. Thus, it costs nothing extra to read and store
// that much so as to speed any additional invocations.
$bytes .= fread($fh, max(4096, $missing_bytes));
fclose($fh);
}
// If we couldn't get enough entropy, this simple hash-based PRNG will
// generate a good set of pseudo-random bytes on any system.
// Note that it may be important that our $random_state is passed
// through hash() prior to being rolled into $output, that the two hash()
// invocations are different, and that the extra input into the first one -
// the microtime() - is prepended rather than appended. This is to avoid
// directly leaking $random_state via the $output stream, which could
// allow for trivial prediction of further "random" numbers.
if (strlen($bytes) < $count) {
// Initialize on the first call. The contents of $_SERVER includes a mix
// of user-specific and system information that varies a little with
// each page.
if (!isset($random_state)) {
$random_state = print_r($_SERVER, TRUE);
if (function_exists('getmypid')) {
// Further initialize with the somewhat random PHP process ID.
$random_state .= getmypid();
}
$bytes = '';
}
do {
$random_state = hash('sha256', microtime() . mt_rand() . $random_state);
$bytes .= hash('sha256', mt_rand() . $random_state, TRUE);
} while (strlen($bytes) < $count);
}
}
$output = substr($bytes, 0, $count);
$bytes = substr($bytes, $count);
return $output;
}
/**
* Calculates a base-64 encoded, URL-safe sha-256 hmac.
*
* @param mixed $data
* Scalar value to be validated with the hmac.
* @param mixed $key
* A secret key, this can be any scalar value.
*
* @return string
* A base-64 encoded sha-256 hmac, with + replaced with -, / with _ and
* any = padding characters removed.
*/
public static function hmacBase64($data, $key) {
// $data and $key being strings here is necessary to avoid empty string
// results of the hash function if they are not scalar values. As this
// function is used in security-critical contexts like token validation it
// is important that it never returns an empty string.
if (!is_scalar($data) || !is_scalar($key)) {
throw new \InvalidArgumentException('Both parameters passed to \\Drupal\\Component\\Utility\\Crypt::hmacBase64 must be scalar values.');
}
$hmac = base64_encode(hash_hmac('sha256', $data, $key, TRUE));
// Modify the hmac so it's safe to use in URLs.
return str_replace([
'+',
'/',
'=',
], [
'-',
'_',
'',
], $hmac);
}
/**
* Calculates a base-64 encoded, URL-safe sha-256 hash.
*
* @param string $data
* String to be hashed.
*
* @return string
* A base-64 encoded sha-256 hash, with + replaced with -, / with _ and
* any = padding characters removed.
*/
public static function hashBase64($data) {
$hash = base64_encode(hash('sha256', $data, TRUE));
// Modify the hash so it's safe to use in URLs.
return str_replace([
'+',
'/',
'=',
], [
'-',
'_',
'',
], $hash);
}
/**
* Compares strings in constant time.
*
* @param string $known_string
* The expected string.
* @param string $user_string
* The user supplied string to check.
*
* @return bool
* Returns TRUE when the two strings are equal, FALSE otherwise.
*/
public static function hashEquals($known_string, $user_string) {
if (function_exists('hash_equals')) {
return hash_equals($known_string, $user_string);
}
else {
// Backport of hash_equals() function from PHP 5.6
// @see https://github.com/php/php-src/blob/PHP-5.6/ext/hash/hash.c#L739
if (!is_string($known_string)) {
trigger_error(sprintf("Expected known_string to be a string, %s given", gettype($known_string)), E_USER_WARNING);
return FALSE;
}
if (!is_string($user_string)) {
trigger_error(sprintf("Expected user_string to be a string, %s given", gettype($user_string)), E_USER_WARNING);
return FALSE;
}
$known_len = strlen($known_string);
if ($known_len !== strlen($user_string)) {
return FALSE;
}
// This is security sensitive code. Do not optimize this for speed.
$result = 0;
for ($i = 0; $i < $known_len; $i++) {
$result |= ord($known_string[$i]) ^ ord($user_string[$i]);
}
return $result === 0;
}
}
/**
* Returns a URL-safe, base64 encoded string of highly randomized bytes.
*
* @param $byte_count
* The number of random bytes to fetch and base64 encode.
*
* @return string
* The base64 encoded result will have a length of up to 4 * $byte_count.
*
* @see \Drupal\Component\Utility\Crypt::randomBytes()
*/
public static function randomBytesBase64($count = 32) {
return str_replace([
'+',
'/',
'=',
], [
'-',
'_',
'',
], base64_encode(static::randomBytes($count)));
}
}