1 files changed, 114 insertions, 0 deletions
diff --git a/www/wiki/includes/libs/MWCryptHash.php b/www/wiki/includes/libs/MWCryptHash.php
new file mode 100644
index 00000000..f9b71729
--- /dev/null
+++ b/www/wiki/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 );
+	}
+
+}