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;
/**
* @brief Class for utilities relating to encrypted file storage system
* @param $view OC_FilesystemView object, expected to have OC '/' as root path
* @param $client flag indicating status of client side encryption. Currently
* unused, likely to become obsolete shortly
*/
class Util {
# Web UI:
## DONE: files created via web ui are encrypted
## DONE: file created & encrypted via web ui are readable in web ui
## DONE: file created & encrypted via web ui are readable via webdav
# WebDAV:
## DONE: new data filled files added via webdav get encrypted
## DONE: new data filled files added via webdav are readable via webdav
## DONE: reading unencrypted files when encryption is enabled works via webdav
## DONE: files created & encrypted via web ui are readable via webdav
# Legacy support:
## DONE: add method to check if file is encrypted using new system
## DONE: add method to check if file is encrypted using old system
## DONE: add method to fetch legacy key
## DONE: add method to decrypt legacy encrypted data
## TODO: add method to encrypt all user files using new system
## TODO: add method to decrypt all user files using new system
## TODO: add method to encrypt all user files using old system
## TODO: add method to decrypt all user files using old system
# Admin UI:
## DONE: changing user password also changes encryption passphrase
## TODO: add support for optional recovery in case of lost passphrase / keys
## TODO: add admin optional required long passphrase for users
## TODO: add UI buttons for encrypt / decrypt everything
## TODO: implement flag system to allow user to specify encryption by folder, subfolder, etc.
# Sharing:
## TODO: add support for encrypting to multiple public keys
## TODO: add support for decrypting to multiple private keys
# Integration testing:
## TODO: test new encryption with webdav
## TODO: test new encryption with versioning
## TODO: test new encryption with sharing
## TODO: test new encryption with proxies
private $view; // OC_FilesystemView object for filesystem operations
private $userId; // ID of the currently logged-in user
private $pwd; // User Password
private $client; // Client side encryption mode flag
private $publicKeyDir; // Dir containing all public user keys
private $encryptionDir; // Dir containing user's files_encryption
private $keyfilesPath; // Dir containing user's keyfiles
private $shareKeysPath; // Dir containing env keys for shared files
private $publicKeyPath; // Path to user's public key
private $privateKeyPath; // Path to user's private key
public function __construct( \OC_FilesystemView $view, $userId, $client = false ) {
$this->view = $view;
$this->userId = $userId;
$this->client = $client;
$this->userDir = '/' . $this->userId;
$this->userFilesDir = '/' . $this->userId . '/' . 'files';
$this->publicKeyDir = '/' . 'public-keys';
$this->encryptionDir = '/' . $this->userId . '/' . 'files_encryption';
$this->keyfilesPath = $this->encryptionDir . '/' . 'keyfiles';
$this->shareKeysPath = $this->encryptionDir . '/' . 'share-keys';
$this->publicKeyPath = $this->publicKeyDir . '/' . $this->userId . '.public.key'; // e.g. data/public-keys/admin.public.key
$this->privateKeyPath = $this->encryptionDir . '/' . $this->userId . '.private.key'; // e.g. data/admin/admin.private.key
}
public function ready() {
if(
!$this->view->file_exists( $this->encryptionDir )
or !$this->view->file_exists( $this->keyfilesPath )
or !$this->view->file_exists( $this->shareKeysPath )
or !$this->view->file_exists( $this->publicKeyPath )
or !$this->view->file_exists( $this->privateKeyPath )
) {
return false;
} else {
return true;
}
}
/**
* @brief Sets up user folders and keys for serverside encryption
* @param $passphrase passphrase to encrypt server-stored private key with
*/
public function setupServerSide( $passphrase = null ) {
// Create user dir
if( !$this->view->file_exists( $this->userDir ) ) {
$this->view->mkdir( $this->userDir );
}
// Create user files dir
if( !$this->view->file_exists( $this->userFilesDir ) ) {
$this->view->mkdir( $this->userFilesDir );
}
// Create shared public key directory
if( !$this->view->file_exists( $this->publicKeyDir ) ) {
$this->view->mkdir( $this->publicKeyDir );
}
// Create encryption app directory
if( !$this->view->file_exists( $this->encryptionDir ) ) {
$this->view->mkdir( $this->encryptionDir );
}
// Create mirrored keyfile directory
if( !$this->view->file_exists( $this->keyfilesPath ) ) {
$this->view->mkdir( $this->keyfilesPath );
}
// Create mirrored share env keys directory
if( !$this->view->file_exists( $this->shareKeysPath ) ) {
$this->view->mkdir( $this->shareKeysPath );
}
// Create user keypair
if (
! $this->view->file_exists( $this->publicKeyPath )
or ! $this->view->file_exists( $this->privateKeyPath )
) {
// Generate keypair
$keypair = Crypt::createKeypair();
\OC_FileProxy::$enabled = false;
// Save public key
$this->view->file_put_contents( $this->publicKeyPath, $keypair['publicKey'] );
// Encrypt private key with user pwd as passphrase
$encryptedPrivateKey = Crypt::symmetricEncryptFileContent( $keypair['privateKey'], $passphrase );
// Save private key
$this->view->file_put_contents( $this->privateKeyPath, $encryptedPrivateKey );
\OC_FileProxy::$enabled = true;
}
$publicKey = Keymanager::getPublicKey( $this->view, $this->userId );
// Encrypt existing user files:
$this->encryptAll( $publicKey, $this->userFilesDir );
return true;
}
/**
* @brief Find all files and their encryption status within a directory
* @param string $directory The path of the parent directory to search
* @return mixed false if 0 found, array on success. Keys: name, path
*/
public function findFiles( $directory ) {
// Disable proxy - we don't want files to be decrypted before
// we handle them
\OC_FileProxy::$enabled = false;
$found = array( 'plain' => array(), 'encrypted' => array(), 'legacy' => array() );
if (
$this->view->is_dir( $directory )
&& $handle = $this->view->opendir( $directory )
) {
while ( false !== ( $file = readdir( $handle ) ) ) {
if (
$file != "."
&& $file != ".."
) {
$filePath = $directory . '/' . $this->view->getRelativePath( '/' . $file );
// If the path is a directory, search
// its contents
if ( $this->view->is_dir( $filePath ) ) {
$this->findFiles( $filePath );
// If the path is a file, determine
// its encryption status
} elseif ( $this->view->is_file( $filePath ) ) {
// Disable proxies again, some-
// how they get re-enabled :/
\OC_FileProxy::$enabled = false;
// If the file is encrypted
if ( Keymanager::getFileKey( $this->view, $this->userId, $file ) ) {
$found['encrypted'][] = array( 'name' => $file, 'path' => $filePath );
// If the file uses old
// encryption system
} elseif ( Crypt::isLegacyEncryptedContent( $this->view->file_get_contents( $filePath ) ) ) {
$found['legacy'][] = array( 'name' => $file, 'path' => $filePath );
// If the file is not encrypted
} else {
$found['plain'][] = array( 'name' => $file, 'path' => $filePath );
}
}
}
}
\OC_FileProxy::$enabled = true;
if ( empty( $found ) ) {
return false;
} else {
return $found;
}
}
\OC_FileProxy::$enabled = true;
return false;
}
/**
* @brief Check if a given path identifies an encrypted file
* @return true / false
*/
public function isEncryptedPath( $path ) {
// Disable encryption proxy so data retreived is in its
// original form
\OC_FileProxy::$enabled = false;
$data = $this->view->file_get_contents( $path );
\OC_FileProxy::$enabled = true;
return Crypt::isCatfile( $data );
}
/**
* @brief Encrypt all files in a directory
* @param string $publicKey the public key to encrypt files with
* @param string $dirPath the directory whose files will be encrypted
* @note Encryption is recursive
*/
public function encryptAll( $publicKey, $dirPath ) {
if ( $found = $this->findFiles( $dirPath ) ) {
// Encrypt unencrypted files
foreach ( $found['plain'] as $plainFilePath ) {
// Fetch data from file
$plainData = $this->view->file_get_contents( $plainFilePath );
// Encrypt data, generate catfile
$encrypted = Crypt::keyEncryptKeyfile( $plainData, $publicKey );
// Save catfile
Keymanager::setFileKey( $this->view, $plainFilePath, $this->userId, $encrypted['key'] );
// Overwrite the existing file with the encrypted one
$this->view->file_put_contents( $plainFilePath, $encrypted['data'] );
}
// FIXME: Legacy recrypting here isn't finished yet
// Encrypt legacy encrypted files
foreach ( $found['legacy'] as $legacyFilePath ) {
// Fetch data from file
$legacyData = $this->view->file_get_contents( $legacyFilePath );
// Recrypt data, generate catfile
$recrypted = Crypt::legacyKeyRecryptKeyfile( $legacyData, $legacyPassphrase, $publicKey, $newPassphrase );
// Save catfile
Keymanager::setFileKey( $this->view, $plainFilePath, $this->userId, $recrypted['key'] );
// Overwrite the existing file with the encrypted one
$this->view->file_put_contents( $plainFilePath, $recrypted['data'] );
}
}
}
public function getPath( $pathName ) {
switch ( $pathName ) {
case 'publicKeyDir':
return $this->publicKeyDir;
break;
case 'encryptionDir':
return $this->encryptionDir;
break;
case 'keyfilesPath':
return $this->keyfilesPath;
break;
case 'publicKeyPath':
return $this->publicKeyPath;
break;
case 'privateKeyPath':
return $this->privateKeyPath;
break;
}
}
}