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