diff core/lib/Drupal/Component/Utility/Crypt.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Component/Utility/Crypt.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,171 @@
+<?php
+
+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.
+   *
+   * In PHP 7 and up, this uses the built-in PHP function random_bytes().
+   * In older PHP versions, this uses the random_bytes() function provided by
+   * the random_compat library, or the fallback hash-based generator from Drupal
+   * 7.x.
+   *
+   * @param int $count
+   *   The number of characters (bytes) to return in the string.
+   *
+   * @return string
+   *   A randomly generated string.
+   */
+  public static function randomBytes($count) {
+    try {
+      return random_bytes($count);
+    }
+    catch (\Exception $e) {
+      // $random_state does not use drupal_static as it stores random bytes.
+      static $random_state, $bytes;
+      // If the compatibility library fails, 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 $_SERVER variable includes user and
+        // system-specific information that varies a little with each page.
+        if (!isset($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 = '';
+          // Ensure mt_rand() is reseeded before calling it the first time.
+          mt_srand();
+        }
+
+        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 $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 * $count.
+   *
+   * @see \Drupal\Component\Utility\Crypt::randomBytes()
+   */
+  public static function randomBytesBase64($count = 32) {
+    return str_replace(['+', '/', '='], ['-', '_', ''], base64_encode(static::randomBytes($count)));
+  }
+
+}