nextcloud/apps/files_encryption/lib/proxy.php

466 lines
11 KiB
PHP

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