514 lines
14 KiB
PHP
514 lines
14 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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class Proxy extends \OC_FileProxy {
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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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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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$rootView = new \OC_FilesystemView( '/' );
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$util = new Util( $rootView, $userId );
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$session = new Session( $rootView );
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$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( $data );
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$enabled = false;
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// Check if there is an existing key we can reuse
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if ( $encKeyfile = Keymanager::getFileKey( $rootView, $userId, $filePath ) ) {
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// Fetch shareKey
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$shareKey = Keymanager::getShareKey( $rootView, $userId, $filePath );
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// Decrypt the keyfile
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$plainKey = Crypt::multiKeyDecrypt( $encKeyfile, $shareKey, $privateKey );
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// trigger_error("\$shareKey = $shareKey");
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// trigger_error("\$plainKey = $plainKey");
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} else {
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// Make a new key
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$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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$uniqueUserIds = $util->getSharingUsersArray( $sharingEnabled, $filePath, $userId );
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// Fetch public keys for all users who will share the file
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$publicKeys = Keymanager::getPublicKeys( $rootView, $uniqueUserIds );
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\OC_FileProxy::$enabled = false;
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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( $rootView, $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( $rootView, $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( $path, array( 'encrypted'=>true, 'size' => $size ), '' );
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// Re-enable proxy - our work is done
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\OC_FileProxy::$enabled = true;
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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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// FIXME: $path for shared files is just /uid/files/Shared/filepath
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$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( $path );
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// TODO check for existing key file and reuse it if possible to avoid problems with versioning etc.
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$enabled = false;
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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( $data ) // TODO: Do we really need this check? Can't we assume it is properly encrypted?
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) {
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// TODO: use get owner to find correct location of key files for shared files
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$session = new Session( $view );
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$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, $plainKeyfile );
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// trigger_error("PLAINDATA = ". var_export($plainData, 1));
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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 = true;
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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( $path ) {
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// let the trashbin handle this
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if ( \OCP\App::isEnabled('files_trashbin') ) {
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return true;
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}
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$path = Keymanager::fixPartialFilePath( $path );
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$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 (
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! (
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Keymanager::deleteFileKey( $view, $owner, $ownerPath )
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&& Keymanager::delAllShareKeys( $view, $owner, $ownerPath )
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)
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) {
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\OC_Log::write( 'Encryption library', 'Keyfile or shareKey could not be deleted for file "'.$ownerPath.'"', \OC_Log::ERROR );
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}
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\OC_FileProxy::$enabled = true;
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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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* @brief When a file is renamed, rename its keyfile also
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* @return bool Result of rename()
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* @note This is pre rather than post because using post didn't work
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*/
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public function preRename( $oldPath, $newPath )
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{
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$enabled = false;
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$view = new \OC_FilesystemView('/');
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$userId = \OCP\USER::getUser();
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// Format paths to be relative to user files dir
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$oldTrimmed = ltrim($oldPath, '/');
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$oldSplit = explode('/', $oldTrimmed);
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$oldSliced = array_slice($oldSplit, 2);
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$oldRelPath = implode('/', $oldSliced);
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$oldKeyfilePath = $userId . '/' . 'files_encryption' . '/' . 'keyfiles' . '/' . $oldRelPath;
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$newTrimmed = ltrim($newPath, '/');
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$newSplit = explode('/', $newTrimmed);
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$newSliced = array_slice($newSplit, 2);
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$newRelPath = implode('/', $newSliced);
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$newKeyfilePath = $userId . '/' . 'files_encryption' . '/' . 'keyfiles' . '/' . $newRelPath;
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// add key ext if this is not an folder
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if (!$view->is_dir($oldKeyfilePath)) {
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$oldKeyfilePath .= '.key';
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$newKeyfilePath .= '.key';
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} else {
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// handle share-keys folders
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$oldShareKeyfilePath = $userId . '/' . 'files_encryption' . '/' . 'share-keys' . '/' . $oldRelPath;
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$newShareKeyfilePath = $userId . '/' . 'files_encryption' . '/' . 'share-keys' . '/' . $newRelPath;
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$view->rename($oldShareKeyfilePath, $newShareKeyfilePath);
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}
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//TODO add support for share-keys files
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//...
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// Rename keyfile so it isn't orphaned
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$result = $view->rename($oldKeyfilePath, $newKeyfilePath);
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\OC_FileProxy::$enabled = true;
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return $result;
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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( $path_split, 3 ) );
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$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 $meta['mode'] != 'rb'
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) {
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// If the file is not yet encrypted, but should be
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// encrypted when it's saved (it's not read only)
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// NOTE: this is the case for new files saved via WebDAV
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if (
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$view->file_exists( $path )
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and $view->filesize( $path ) > 0
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) {
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$x = $view->file_get_contents( $path );
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$tmp = tmpfile();
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// // Make a temporary copy of the original file
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// \OCP\Files::streamCopy( $result, $tmp );
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//
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// // Close the original stream, we'll return another one
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// fclose( $result );
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//
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// $view->file_put_contents( $path_f, $tmp );
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//
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// fclose( $tmp );
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}
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$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 = true;
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return $result;
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}
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public function postGetMimeType( $path, $mime ) {
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if ( Crypt::isCatfileContent( $path ) ) {
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$mime = \OCP\Files::getMimeType( 'crypt://' . $path, 'w' );
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}
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return $mime;
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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', $data)) {
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$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 = true;
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trigger_error('postGetFileInfo '.$path.' size: '.$data['size']);
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}
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return $data;
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}
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public function postStat( $path, $data ) {
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if ( Crypt::isCatfileContent( $path ) ) {
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$cached = \OC\Files\Filesystem::getFileInfo( $path, '' );
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$data['size'] = $cached['size'];
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}
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return $data;
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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($path_split, 3));
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$userId = \OCP\User::getUser();
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$util = new Util( $view, $userId );
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// FIXME: is there a better solution to check if file belongs to files path?
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// only get file size if file is in 'files' path
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if (count($path_split) >= 2 && $path_split[2] == 'files' && $util->isEncryptedPath($path)) {
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// Disable encryption proxy to prevent recursive calls
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\OC_FileProxy::$enabled = false;
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// open stream
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$result = fopen('crypt://' . $path_f, "r");
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if(is_resource($result)) {
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// don't trust the given size, allways get the size from filesystem
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$size = $view->filesize($path);
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// calculate last chunk nr
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$lastChunckNr = floor($size / 8192);
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// calculate last chunk position
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$lastChunckPos = ($lastChunckNr * 8192);
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// seek to end
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fseek($result, $lastChunckPos);
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// get the content of the last chunck
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$lastChunkContent = fgets($result);
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// calc the real file size with the size of the last chunk
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$realSize = (($lastChunckNr * 6126) + strlen($lastChunkContent));
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// set the size
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$size = $realSize;
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}
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// enable proxy
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\OC_FileProxy::$enabled = true;
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return $size;
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} else {
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return $size;
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}
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}
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}
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