nextcloud/apps/files_encryption/lib/util.php

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<?php
/**
* ownCloud
*
* @author Sam Tuke, Frank Karlitschek
* @copyright 2012 Sam Tuke samtuke@owncloud.com,
* Frank Karlitschek frank@owncloud.org
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
* License as published by the Free Software Foundation; either
* version 3 of the License, or any later version.
*
* This library 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 along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*/
// Todo:
// - Crypt/decrypt button in the userinterface
// - Setting if crypto should be on by default
// - Add a setting "Don´t encrypt files larger than xx because of performance reasons"
// - Transparent decrypt/encrypt in filesystem.php. Autodetect if a file is encrypted (.encrypted extension)
// - Don't use a password directly as encryption key. but a key which is stored on the server and encrypted with the user password. -> password change faster
// - IMPORTANT! Check if the block lenght of the encrypted data stays the same
namespace OCA_Encryption;
/**
* Class for utilities relating to encrypted file storage system
*/
class Util {
private $view; // OC_FilesystemView object for filesystem operations
private $pwd; // User Password
private $client; // Client side encryption mode flag
/**
* @brief get a list of all available versions of a file in descending chronological order
* @param $filename file to find versions of, relative to the user files dir
* @param $count number of versions to return
* @returns array
*/
public function __construct( \OC_FilesystemView $view, $client = false ) {
$this->view = $view;
$this->client = $client;
}
public function ready() {
if(
!$this->view->file_exists( '/' . 'keyfiles' )
or !$this->view->file_exists( '/' . 'keypair' )
or !$this->view->file_exists( '/' . 'keypair' . '/'. 'encryption.public.key' )
or !$this->view->file_exists( '/' . 'keypair' . '/'. 'encryption.private.key' )
) {
return false;
} else {
return true;
}
}
public function setup( $passphrase = null ) {
$publicKeyFileName = 'encryption.public.key';
$privateKeyFileName = 'encryption.private.key';
// Log changes to user's filesystem
$this->appInfo = \OC_APP::getAppInfo( 'files_encryption' );
\OC_Log::write( $this->appInfo['name'], 'File encryption for user will be set up' , \OC_Log::INFO );
// Create mirrored keyfile directory
if( !$this->view->file_exists( '/' . 'keyfiles' ) ) {
$this->view->mkdir( '/'. 'keyfiles' );
}
// Create keypair directory
if( !$this->view->file_exists( '/'. 'keypair' ) ) {
$this->view->mkdir( '/'. 'keypair' );
}
// Create user keypair
if (
!$this->view->file_exists( '/'. 'keypair'. '/' . $publicKeyFileName )
or !$this->view->file_exists( '/'. 'keypair'. '/' . $privateKeyFileName )
) {
// Generate keypair
$keypair = Crypt::createKeypair();
// Save public key
$this->view->file_put_contents( '/'. 'keypair'. '/' . $publicKeyFileName, $keypair['publicKey'] );
if ( $this->client == false ) {
# TODO: Use proper IV in encryption
// Encrypt private key with user pwd as passphrase
$encryptedPrivateKey = Crypt::createSymmetricKeyfile( $keypair['privateKey'], $passphrase );
// $iv = openssl_random_pseudo_bytes(16);
$this->view->file_put_contents( '/'. 'keypair'. '/' . $privateKeyFileName, $encryptedPrivateKey );
} else {
# TODO PHASE2: add public key to keyserver for client-side
# TODO PHASE2: encrypt private key using password / new client side specified key, instead of existing user pwd
}
}
}
}