465 lines
11 KiB
PHP
465 lines
11 KiB
PHP
<?php
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/**
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* ownCloud
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*
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* @author Sam Tuke, Robin Appelman
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* @copyright 2012 Sam Tuke samtuke@owncloud.com, Robin Appelman
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* icewind1991@gmail.com
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or any later version.
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*
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* This library 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 AFFERO GENERAL PUBLIC LICENSE for more details.
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*
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* You should have received a copy of the GNU Affero General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/**
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* @brief Encryption proxy which handles filesystem operations before and after
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* execution and encrypts, and handles keyfiles accordingly. Used for
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* webui.
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*/
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namespace OCA\Encryption;
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/**
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* Class Proxy
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* @package OCA\Encryption
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*/
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class Proxy extends \OC_FileProxy
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{
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private static $blackList = null; //mimetypes blacklisted from encryption
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private static $enableEncryption = null;
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/**
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* Check if a file requires encryption
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* @param string $path
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* @return bool
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*
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* Tests if server side encryption is enabled, and file is allowed by blacklists
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*/
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private static function shouldEncrypt( $path ) {
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if ( is_null( self::$enableEncryption ) ) {
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if (
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\OCP\Config::getAppValue( 'files_encryption', 'enable_encryption', 'true' ) == 'true'
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&& Crypt::mode() == 'server'
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) {
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self::$enableEncryption = true;
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} else {
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self::$enableEncryption = false;
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}
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}
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if ( !self::$enableEncryption ) {
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return false;
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}
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if ( is_null( self::$blackList ) ) {
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self::$blackList = explode( ',', \OCP\Config::getAppValue( 'files_encryption', 'type_blacklist', '' ) );
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}
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if ( Crypt::isCatfileContent( $path ) ) {
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return true;
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}
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$extension = substr( $path, strrpos( $path, '.' ) + 1 );
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if ( array_search( $extension, self::$blackList ) === false ) {
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return true;
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}
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return false;
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}
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/**
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* @param $path
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* @param $data
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* @return bool
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*/
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public function preFile_put_contents( $path, &$data ) {
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if ( self::shouldEncrypt( $path ) ) {
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// Stream put contents should have been converted to fopen
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if ( !is_resource( $data ) ) {
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$userId = \OCP\USER::getUser();
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$view = new \OC_FilesystemView( '/' );
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$util = new Util( $view, $userId );
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$session = new Session( $view );
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$privateKey = $session->getPrivateKey();
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$filePath = $util->stripUserFilesPath( $path );
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// Set the filesize for userland, before encrypting
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$size = strlen( $data );
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// Disable encryption proxy to prevent recursive calls
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$proxyStatus = \OC_FileProxy::$enabled;
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\OC_FileProxy::$enabled = false;
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// Check if there is an existing key we can reuse
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if ( $encKeyfile = Keymanager::getFileKey( $view, $userId, $filePath ) ) {
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// Fetch shareKey
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$shareKey = Keymanager::getShareKey( $view, $userId, $filePath );
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// Decrypt the keyfile
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$plainKey = Crypt::multiKeyDecrypt( $encKeyfile, $shareKey, $privateKey );
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} else {
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// Make a new key
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$plainKey = Crypt::generateKey();
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}
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// Encrypt data
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$encData = Crypt::symmetricEncryptFileContent( $data, $plainKey );
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$sharingEnabled = \OCP\Share::isEnabled();
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// if file exists try to get sharing users
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if ( $view->file_exists( $path ) ) {
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$uniqueUserIds = $util->getSharingUsersArray( $sharingEnabled, $filePath, $userId );
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} else {
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$uniqueUserIds[] = $userId;
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}
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// Fetch public keys for all users who will share the file
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$publicKeys = Keymanager::getPublicKeys( $view, $uniqueUserIds );
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// Encrypt plain keyfile to multiple sharefiles
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$multiEncrypted = Crypt::multiKeyEncrypt( $plainKey, $publicKeys );
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// Save sharekeys to user folders
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Keymanager::setShareKeys( $view, $filePath, $multiEncrypted['keys'] );
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// Set encrypted keyfile as common varname
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$encKey = $multiEncrypted['data'];
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// Save keyfile for newly encrypted file in parallel directory tree
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Keymanager::setFileKey( $view, $filePath, $userId, $encKey );
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// Replace plain content with encrypted content by reference
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$data = $encData;
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// Update the file cache with file info
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\OC\Files\Filesystem::putFileInfo( $filePath, array( 'encrypted' => true, 'size' => strlen( $data ), 'unencrypted_size' => $size ), '' );
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// Re-enable proxy - our work is done
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\OC_FileProxy::$enabled = $proxyStatus;
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}
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}
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return true;
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}
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/**
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* @param string $path Path of file from which has been read
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* @param string $data Data that has been read from file
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*/
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public function postFile_get_contents( $path, $data ) {
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$userId = \OCP\USER::getUser();
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$view = new \OC_FilesystemView( '/' );
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$util = new Util( $view, $userId );
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$relPath = $util->stripUserFilesPath( $path );
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// Disable encryption proxy to prevent recursive calls
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$proxyStatus = \OC_FileProxy::$enabled;
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\OC_FileProxy::$enabled = false;
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// init session
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$session = new Session( $view );
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// If data is a catfile
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if (
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Crypt::mode() == 'server'
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&& Crypt::isCatfileContent( $data )
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) {
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$privateKey = $session->getPrivateKey( $userId );
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// Get the encrypted keyfile
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$encKeyfile = Keymanager::getFileKey( $view, $userId, $relPath );
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// Attempt to fetch the user's shareKey
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$shareKey = Keymanager::getShareKey( $view, $userId, $relPath );
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// Decrypt keyfile with shareKey
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$plainKeyfile = Crypt::multiKeyDecrypt( $encKeyfile, $shareKey, $privateKey );
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$plainData = Crypt::symmetricDecryptFileContent( $data, $plainKeyfile );
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} elseif (
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Crypt::mode() == 'server'
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&& isset( $_SESSION['legacyenckey'] )
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&& Crypt::isEncryptedMeta( $path )
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) {
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$plainData = Crypt::legacyDecrypt( $data, $session->getLegacyKey() );
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}
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\OC_FileProxy::$enabled = $proxyStatus;
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if ( !isset( $plainData ) ) {
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$plainData = $data;
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}
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return $plainData;
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}
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/**
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* @brief When a file is deleted, remove its keyfile also
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*/
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public function preUnlink( $path ) {
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// let the trashbin handle this
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if ( \OCP\App::isEnabled( 'files_trashbin' ) ) {
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return true;
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}
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// Disable encryption proxy to prevent recursive calls
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$proxyStatus = \OC_FileProxy::$enabled;
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\OC_FileProxy::$enabled = false;
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$view = new \OC_FilesystemView( '/' );
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$userId = \OCP\USER::getUser();
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$util = new Util( $view, $userId );
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// Format path to be relative to user files dir
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$relPath = $util->stripUserFilesPath( $path );
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list( $owner, $ownerPath ) = $util->getUidAndFilename( $relPath );
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// Delete keyfile & shareKey so it isn't orphaned
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if ( !Keymanager::deleteFileKey( $view, $owner, $ownerPath ) ) {
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\OC_Log::write( 'Encryption library', 'Keyfile or shareKey could not be deleted for file "' . $ownerPath . '"', \OC_Log::ERROR );
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}
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Keymanager::delAllShareKeys( $view, $owner, $ownerPath );
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\OC_FileProxy::$enabled = $proxyStatus;
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// If we don't return true then file delete will fail; better
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// to leave orphaned keyfiles than to disallow file deletion
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return true;
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}
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/**
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* @param $path
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* @return bool
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*/
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public function postTouch( $path ) {
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$this->handleFile( $path );
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return true;
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}
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/**
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* @param $path
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* @param $result
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* @return resource
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*/
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public function postFopen( $path, &$result ) {
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if ( !$result ) {
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return $result;
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}
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// Reformat path for use with OC_FSV
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$path_split = explode( '/', $path );
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$path_f = implode( '/', array_slice( $path_split, 3 ) );
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// FIXME: handling for /userId/cache used by webdav for chunking. The cache chunks are NOT encrypted
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if ( count($path_split) >= 2 && $path_split[2] == 'cache' ) {
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return $result;
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}
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// Disable encryption proxy to prevent recursive calls
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$proxyStatus = \OC_FileProxy::$enabled;
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\OC_FileProxy::$enabled = false;
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$meta = stream_get_meta_data( $result );
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$view = new \OC_FilesystemView( '' );
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$util = new Util( $view, \OCP\USER::getUser() );
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// If file is already encrypted, decrypt using crypto protocol
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if (
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Crypt::mode() == 'server'
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&& $util->isEncryptedPath( $path )
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) {
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// Close the original encrypted file
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fclose( $result );
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// Open the file using the crypto stream wrapper
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// protocol and let it do the decryption work instead
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$result = fopen( 'crypt://' . $path_f, $meta['mode'] );
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} elseif (
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self::shouldEncrypt( $path )
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and $meta ['mode'] != 'r'
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and $meta['mode'] != 'rb'
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) {
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$result = fopen( 'crypt://' . $path_f, $meta['mode'] );
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}
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// Re-enable the proxy
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\OC_FileProxy::$enabled = $proxyStatus;
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return $result;
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}
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/**
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* @param $path
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* @param $data
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* @return array
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*/
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public function postGetFileInfo( $path, $data ) {
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// if path is a folder do nothing
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if ( is_array( $data ) && array_key_exists( 'size', $data ) ) {
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// Disable encryption proxy to prevent recursive calls
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$proxyStatus = \OC_FileProxy::$enabled;
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\OC_FileProxy::$enabled = false;
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// get file size
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$data['size'] = self::postFileSize( $path, $data['size'] );
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// Re-enable the proxy
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\OC_FileProxy::$enabled = $proxyStatus;
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}
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return $data;
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}
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/**
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* @param $path
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* @param $size
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* @return bool
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*/
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public function postFileSize( $path, $size ) {
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$view = new \OC_FilesystemView( '/' );
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// if path is a folder do nothing
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if ( $view->is_dir( $path ) ) {
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return $size;
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}
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// Reformat path for use with OC_FSV
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$path_split = explode( '/', $path );
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$path_f = implode( '/', array_slice( $path_split, 3 ) );
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// if path is empty we cannot resolve anything
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if ( empty( $path_f ) ) {
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return $size;
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}
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$fileInfo = false;
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// get file info from database/cache if not .part file
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if ( !Keymanager::isPartialFilePath( $path ) ) {
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$fileInfo = $view->getFileInfo( $path );
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}
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// if file is encrypted return real file size
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if ( is_array( $fileInfo ) && $fileInfo['encrypted'] === true ) {
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$size = $fileInfo['unencrypted_size'];
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} else {
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// self healing if file was removed from file cache
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if ( !is_array( $fileInfo ) ) {
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$fileInfo = array();
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}
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$userId = \OCP\User::getUser();
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$util = new Util( $view, $userId );
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$fixSize = $util->getFileSize( $path );
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if ( $fixSize > 0 ) {
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$size = $fixSize;
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$fileInfo['encrypted'] = true;
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$fileInfo['unencrypted_size'] = $size;
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// put file info if not .part file
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if ( !Keymanager::isPartialFilePath( $path_f ) ) {
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$view->putFileInfo( $path, $fileInfo );
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}
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}
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}
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return $size;
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}
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/**
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* @param $path
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*/
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public function handleFile( $path ) {
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// Disable encryption proxy to prevent recursive calls
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$proxyStatus = \OC_FileProxy::$enabled;
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\OC_FileProxy::$enabled = false;
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$view = new \OC_FilesystemView( '/' );
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$session = new Session( $view );
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$userId = \OCP\User::getUser();
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$util = new Util( $view, $userId );
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// Reformat path for use with OC_FSV
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$path_split = explode( '/', $path );
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$path_f = implode( '/', array_slice( $path_split, 3 ) );
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// only if file is on 'files' folder fix file size and sharing
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if ( count($path_split) >= 2 && $path_split[2] == 'files' && $util->fixFileSize( $path ) ) {
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// get sharing app state
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$sharingEnabled = \OCP\Share::isEnabled();
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// get users
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$usersSharing = $util->getSharingUsersArray( $sharingEnabled, $path_f );
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// update sharing-keys
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$util->setSharedFileKeyfiles( $session, $usersSharing, $path_f );
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}
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\OC_FileProxy::$enabled = $proxyStatus;
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}
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}
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