nextcloud/lib/private/Security/Hasher.php

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<?php
/**
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* @author Lukas Reschke <lukas@statuscode.ch>
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* @author Morris Jobke <hey@morrisjobke.de>
*
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* @copyright Copyright (c) 2016, ownCloud, Inc.
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* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
namespace OC\Security;
use OCP\IConfig;
use OCP\Security\IHasher;
/**
* Class Hasher provides some basic hashing functions. Furthermore, it supports legacy hashes
* used by previous versions of ownCloud and helps migrating those hashes to newer ones.
*
* The hashes generated by this class are prefixed (version|hash) with a version parameter to allow possible
* updates in the future.
* Possible versions:
* - 1 (Initial version)
*
* Usage:
* // Hashing a message
* $hash = \OC::$server->getHasher()->hash('MessageToHash');
* // Verifying a message - $newHash will contain the newly calculated hash
* $newHash = null;
* var_dump(\OC::$server->getHasher()->verify('a', '86f7e437faa5a7fce15d1ddcb9eaeaea377667b8', $newHash));
* var_dump($newHash);
*
* @package OC\Security
*/
class Hasher implements IHasher {
/** @var IConfig */
private $config;
/** @var array Options passed to password_hash and password_needs_rehash */
private $options = array();
/** @var string Salt used for legacy passwords */
private $legacySalt = null;
/** @var int Current version of the generated hash */
private $currentVersion = 1;
/**
* @param IConfig $config
*/
function __construct(IConfig $config) {
$this->config = $config;
$hashingCost = $this->config->getSystemValue('hashingCost', null);
if(!is_null($hashingCost)) {
$this->options['cost'] = $hashingCost;
}
}
/**
* Hashes a message using PHP's `password_hash` functionality.
* Please note that the size of the returned string is not guaranteed
* and can be up to 255 characters.
*
* @param string $message Message to generate hash from
* @return string Hash of the message with appended version parameter
*/
public function hash($message) {
return $this->currentVersion . '|' . password_hash($message, PASSWORD_DEFAULT, $this->options);
}
/**
* Get the version and hash from a prefixedHash
* @param string $prefixedHash
* @return null|array Null if the hash is not prefixed, otherwise array('version' => 1, 'hash' => 'foo')
*/
protected function splitHash($prefixedHash) {
$explodedString = explode('|', $prefixedHash, 2);
if(sizeof($explodedString) === 2) {
if((int)$explodedString[0] > 0) {
return array('version' => (int)$explodedString[0], 'hash' => $explodedString[1]);
}
}
return null;
}
/**
* Verify legacy hashes
* @param string $message Message to verify
* @param string $hash Assumed hash of the message
* @param null|string &$newHash Reference will contain the updated hash
* @return bool Whether $hash is a valid hash of $message
*/
protected function legacyHashVerify($message, $hash, &$newHash = null) {
if(empty($this->legacySalt)) {
$this->legacySalt = $this->config->getSystemValue('passwordsalt', '');
}
// Verify whether it matches a legacy PHPass or SHA1 string
$hashLength = strlen($hash);
if($hashLength === 60 && password_verify($message.$this->legacySalt, $hash) ||
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$hashLength === 40 && hash_equals($hash, sha1($message))) {
$newHash = $this->hash($message);
return true;
}
return false;
}
/**
* Verify V1 hashes
* @param string $message Message to verify
* @param string $hash Assumed hash of the message
* @param null|string &$newHash Reference will contain the updated hash if necessary. Update the existing hash with this one.
* @return bool Whether $hash is a valid hash of $message
*/
protected function verifyHashV1($message, $hash, &$newHash = null) {
if(password_verify($message, $hash)) {
if(password_needs_rehash($hash, PASSWORD_DEFAULT, $this->options)) {
$newHash = $this->hash($message);
}
return true;
}
return false;
}
/**
* @param string $message Message to verify
* @param string $hash Assumed hash of the message
* @param null|string &$newHash Reference will contain the updated hash if necessary. Update the existing hash with this one.
* @return bool Whether $hash is a valid hash of $message
*/
public function verify($message, $hash, &$newHash = null) {
$splittedHash = $this->splitHash($hash);
if(isset($splittedHash['version'])) {
switch ($splittedHash['version']) {
case 1:
return $this->verifyHashV1($message, $splittedHash['hash'], $newHash);
}
} else {
return $this->legacyHashVerify($message, $hash, $newHash);
}
return false;
}
}