You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
149 lines
4.4 KiB
149 lines
4.4 KiB
<?php
|
|
|
|
declare(strict_types=1);
|
|
|
|
/**
|
|
* @copyright Copyright (c) 2016, ownCloud, Inc.
|
|
*
|
|
* @author Andreas Fischer <bantu@owncloud.com>
|
|
* @author Christoph Wurst <christoph@winzerhof-wurst.at>
|
|
* @author Lukas Reschke <lukas@statuscode.ch>
|
|
* @author Morris Jobke <hey@morrisjobke.de>
|
|
* @author Roeland Jago Douma <roeland@famdouma.nl>
|
|
*
|
|
* @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\ICrypto;
|
|
use OCP\Security\ISecureRandom;
|
|
use phpseclib\Crypt\AES;
|
|
use phpseclib\Crypt\Hash;
|
|
|
|
/**
|
|
* Class Crypto provides a high-level encryption layer using AES-CBC. If no key has been provided
|
|
* it will use the secret defined in config.php as key. Additionally the message will be HMAC'd.
|
|
*
|
|
* Usage:
|
|
* $encryptWithDefaultPassword = \OC::$server->getCrypto()->encrypt('EncryptedText');
|
|
* $encryptWithCustompassword = \OC::$server->getCrypto()->encrypt('EncryptedText', 'password');
|
|
*
|
|
* @package OC\Security
|
|
*/
|
|
class Crypto implements ICrypto {
|
|
/** @var AES $cipher */
|
|
private $cipher;
|
|
/** @var int */
|
|
private $ivLength = 16;
|
|
/** @var IConfig */
|
|
private $config;
|
|
|
|
/**
|
|
* @param IConfig $config
|
|
* @param ISecureRandom $random
|
|
*/
|
|
public function __construct(IConfig $config) {
|
|
$this->cipher = new AES();
|
|
$this->config = $config;
|
|
}
|
|
|
|
/**
|
|
* @param string $message The message to authenticate
|
|
* @param string $password Password to use (defaults to `secret` in config.php)
|
|
* @return string Calculated HMAC
|
|
*/
|
|
public function calculateHMAC(string $message, string $password = ''): string {
|
|
if ($password === '') {
|
|
$password = $this->config->getSystemValue('secret');
|
|
}
|
|
|
|
// Append an "a" behind the password and hash it to prevent reusing the same password as for encryption
|
|
$password = hash('sha512', $password . 'a');
|
|
|
|
$hash = new Hash('sha512');
|
|
$hash->setKey($password);
|
|
return $hash->hash($message);
|
|
}
|
|
|
|
/**
|
|
* Encrypts a value and adds an HMAC (Encrypt-Then-MAC)
|
|
* @param string $plaintext
|
|
* @param string $password Password to encrypt, if not specified the secret from config.php will be taken
|
|
* @return string Authenticated ciphertext
|
|
*/
|
|
public function encrypt(string $plaintext, string $password = ''): string {
|
|
if ($password === '') {
|
|
$password = $this->config->getSystemValue('secret');
|
|
}
|
|
$this->cipher->setPassword($password);
|
|
|
|
$iv = \random_bytes($this->ivLength);
|
|
$this->cipher->setIV($iv);
|
|
|
|
$ciphertext = bin2hex($this->cipher->encrypt($plaintext));
|
|
$iv = bin2hex($iv);
|
|
$hmac = bin2hex($this->calculateHMAC($ciphertext.$iv, $password));
|
|
|
|
return $ciphertext.'|'.$iv.'|'.$hmac.'|2';
|
|
}
|
|
|
|
/**
|
|
* Decrypts a value and verifies the HMAC (Encrypt-Then-Mac)
|
|
* @param string $authenticatedCiphertext
|
|
* @param string $password Password to encrypt, if not specified the secret from config.php will be taken
|
|
* @return string plaintext
|
|
* @throws \Exception If the HMAC does not match
|
|
* @throws \Exception If the decryption failed
|
|
*/
|
|
public function decrypt(string $authenticatedCiphertext, string $password = ''): string {
|
|
if ($password === '') {
|
|
$password = $this->config->getSystemValue('secret');
|
|
}
|
|
$this->cipher->setPassword($password);
|
|
|
|
$parts = explode('|', $authenticatedCiphertext);
|
|
$partCount = \count($parts);
|
|
if ($partCount < 3 || $partCount > 4) {
|
|
throw new \Exception('Authenticated ciphertext could not be decoded.');
|
|
}
|
|
|
|
$ciphertext = hex2bin($parts[0]);
|
|
$iv = $parts[1];
|
|
$hmac = hex2bin($parts[2]);
|
|
|
|
if ($partCount === 4) {
|
|
$version = $parts[3];
|
|
if ($version === '2') {
|
|
$iv = hex2bin($iv);
|
|
}
|
|
}
|
|
|
|
$this->cipher->setIV($iv);
|
|
|
|
if (!hash_equals($this->calculateHMAC($parts[0] . $parts[1], $password), $hmac)) {
|
|
throw new \Exception('HMAC does not match.');
|
|
}
|
|
|
|
$result = $this->cipher->decrypt($ciphertext);
|
|
if ($result === false) {
|
|
throw new \Exception('Decryption failed');
|
|
}
|
|
|
|
return $result;
|
|
}
|
|
}
|