MediaWiki 1.30.2

[autoinstallsdev/mediawiki.git] / includes / libs / MWCryptHash.php

diff --git a/includes/libs/MWCryptHash.php b/includes/libs/MWCryptHash.php
new file mode 100644 (file)
index 0000000..f9b7172
--- /dev/null
+++ b/includes/libs/MWCryptHash.php
@@ -0,0 +1,114 @@
+<?php
+/**
+ * Utility functions for generating hashes
+ *
+ * This is based in part on Drupal code as well as what we used in our own code
+ * prior to introduction of this class, by way of MWCryptRand.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+class MWCryptHash {
+       /**
+        * The hash algorithm being used
+        */
+       protected static $algo = null;
+
+       /**
+        * The number of bytes outputted by the hash algorithm
+        */
+       protected static $hashLength = [
+               true => null,
+               false => null,
+       ];
+
+       /**
+        * Decide on the best acceptable hash algorithm we have available for hash()
+        * @return string A hash algorithm
+        */
+       public static function hashAlgo() {
+               if ( !is_null( self::$algo ) ) {
+                       return self::$algo;
+               }
+
+               $algos = hash_algos();
+               $preference = [ 'whirlpool', 'sha256', 'sha1', 'md5' ];
+
+               foreach ( $preference as $algorithm ) {
+                       if ( in_array( $algorithm, $algos ) ) {
+                               self::$algo = $algorithm;
+
+                               return self::$algo;
+                       }
+               }
+
+               // We only reach here if no acceptable hash is found in the list, this should
+               // be a technical impossibility since most of php's hash list is fixed and
+               // some of the ones we list are available as their own native functions
+               // But since we already require at least 5.2 and hash() was default in
+               // 5.1.2 we don't bother falling back to methods like sha1 and md5.
+               throw new DomainException( "Could not find an acceptable hashing function in hash_algos()" );
+       }
+
+       /**
+        * Return the byte-length output of the hash algorithm we are
+        * using in self::hash and self::hmac.
+        *
+        * @param bool $raw True to return the length for binary data, false to
+        *   return for hex-encoded
+        * @return int Number of bytes the hash outputs
+        */
+       public static function hashLength( $raw = true ) {
+               $raw = (bool)$raw;
+               if ( is_null( self::$hashLength[$raw] ) ) {
+                       self::$hashLength[$raw] = strlen( self::hash( '', $raw ) );
+               }
+
+               return self::$hashLength[$raw];
+       }
+
+       /**
+        * Generate an acceptably unstable one-way-hash of some text
+        * making use of the best hash algorithm that we have available.
+        *
+        * @param string $data
+        * @param bool $raw True to return binary data, false to return it hex-encoded
+        * @return string A hash of the data
+        */
+       public static function hash( $data, $raw = true ) {
+               return hash( self::hashAlgo(), $data, $raw );
+       }
+
+       /**
+        * Generate an acceptably unstable one-way-hmac of some text
+        * making use of the best hash algorithm that we have available.
+        *
+        * @param string $data
+        * @param string $key
+        * @param bool $raw True to return binary data, false to return it hex-encoded
+        * @return string An hmac hash of the data + key
+        */
+       public static function hmac( $data, $key, $raw = true ) {
+               if ( !is_string( $key ) ) {
+                       // a fatal error in HHVM; an exception will at least give us a stack trace
+                       throw new InvalidArgumentException( 'Invalid key type: ' . gettype( $key ) );
+               }
+               return hash_hmac( self::hashAlgo(), $data, $key, $raw );
+       }
+
+}