server/lib/private/files/storage/wrapper/encryption.php

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<?php
/**
* @author Björn Schießle <schiessle@owncloud.com>
* @author Thomas Müller <thomas.mueller@tmit.eu>
*
* @copyright Copyright (c) 2015, ownCloud, Inc.
* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program 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, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
namespace OC\Files\Storage\Wrapper;
use OC\Encryption\Exceptions\ModuleDoesNotExistsException;
use OC\Files\Storage\LocalTempFileTrait;
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use OCP\Files\Mount\IMountPoint;
class Encryption extends Wrapper {
use LocalTempFileTrait;
/** @var string */
private $mountPoint;
/** @var \OC\Encryption\Util */
private $util;
/** @var \OC\Encryption\Manager */
private $encryptionManager;
/** @var \OC\Log */
private $logger;
/** @var string */
private $uid;
/** @var array */
private $unencryptedSize;
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/** @var \OC\Encryption\File */
private $fileHelper;
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/** @var IMountPoint */
private $mount;
/**
* @param array $parameters
* @param \OC\Encryption\Manager $encryptionManager
* @param \OC\Encryption\Util $util
* @param \OC\Log $logger
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* @param \OC\Encryption\File $fileHelper
* @param string $uid user who perform the read/write operation (null for public access)
*/
public function __construct(
$parameters,
\OC\Encryption\Manager $encryptionManager = null,
\OC\Encryption\Util $util = null,
\OC\Log $logger = null,
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\OC\Encryption\File $fileHelper = null,
$uid = null
) {
$this->mountPoint = $parameters['mountPoint'];
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$this->mount = $parameters['mount'];
$this->encryptionManager = $encryptionManager;
$this->util = $util;
$this->logger = $logger;
$this->uid = $uid;
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$this->fileHelper = $fileHelper;
$this->unencryptedSize = array();
parent::__construct($parameters);
}
/**
* see http://php.net/manual/en/function.filesize.php
* The result for filesize when called on a folder is required to be 0
*
* @param string $path
* @return int
*/
public function filesize($path) {
$fullPath = $this->getFullPath($path);
$size = $this->storage->filesize($path);
$info = $this->getCache()->get($path);
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if (isset($this->unencryptedSize[$fullPath])) {
$size = $this->unencryptedSize[$fullPath];
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}
if (isset($info['fileid'])) {
$info['encrypted'] = true;
$info['size'] = $size;
$this->getCache()->put($path, $info);
}
return $size;
}
/**
* see http://php.net/manual/en/function.file_get_contents.php
*
* @param string $path
* @return string
*/
public function file_get_contents($path) {
$encryptionModule = $this->getEncryptionModule($path);
if ($encryptionModule) {
$handle = $this->fopen($path, "r");
if (!$handle) {
return false;
}
$data = stream_get_contents($handle);
fclose($handle);
return $data;
}
return $this->storage->file_get_contents($path);
}
/**
* see http://php.net/manual/en/function.file_put_contents.php
*
* @param string $path
* @param string $data
* @return bool
*/
public function file_put_contents($path, $data) {
// file put content will always be translated to a stream write
$handle = $this->fopen($path, 'w');
$written = fwrite($handle, $data);
fclose($handle);
return $written;
}
/**
* see http://php.net/manual/en/function.unlink.php
*
* @param string $path
* @return bool
*/
public function unlink($path) {
if ($this->util->isExcluded($path)) {
return $this->storage->unlink($path);
}
$encryptionModule = $this->getEncryptionModule($path);
if ($encryptionModule) {
$keyStorage = $this->getKeyStorage($encryptionModule->getId());
$keyStorage->deleteAllFileKeys($this->getFullPath($path));
}
return $this->storage->unlink($path);
}
/**
* see http://php.net/manual/en/function.rename.php
*
* @param string $path1
* @param string $path2
* @return bool
*/
public function rename($path1, $path2) {
if ($this->util->isExcluded($path1)) {
return $this->storage->rename($path1, $path2);
}
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$source = $this->getFullPath($path1);
$result = $this->storage->rename($path1, $path2);
if ($result) {
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$target = $this->getFullPath($path2);
$encryptionModule = $this->getEncryptionModule($path2);
if ($encryptionModule) {
$keyStorage = $this->getKeyStorage($encryptionModule->getId());
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$keyStorage->renameKeys($source, $target);
}
}
return $result;
}
/**
* see http://php.net/manual/en/function.copy.php
*
* @param string $path1
* @param string $path2
* @return bool
*/
public function copy($path1, $path2) {
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if ($this->util->isExcluded($path1)) {
return $this->storage->rename($path1, $path2);
}
$source = $this->getFullPath($path1);
$result = $this->storage->copy($path1, $path2);
if ($result) {
$target = $this->getFullPath($path2);
$encryptionModule = $this->getEncryptionModule($path2);
if ($encryptionModule) {
$keyStorage = $this->getKeyStorage($encryptionModule->getId());
$keyStorage->copyKeys($source, $target);
}
}
return $result;
}
/**
* see http://php.net/manual/en/function.fopen.php
*
* @param string $path
* @param string $mode
* @return resource
*/
public function fopen($path, $mode) {
$shouldEncrypt = false;
$encryptionModule = null;
$header = $this->getHeader($path);
$fullPath = $this->getFullPath($path);
$encryptionModuleId = $this->util->getEncryptionModuleId($header);
$size = $unencryptedSize = 0;
$targetExists = $this->file_exists($path);
$targetIsEncrypted = false;
if ($targetExists) {
// in case the file exists we require the explicit module as
// specified in the file header - otherwise we need to fail hard to
// prevent data loss on client side
if (!empty($encryptionModuleId)) {
$targetIsEncrypted = true;
$encryptionModule = $this->encryptionManager->getEncryptionModule($encryptionModuleId);
}
$size = $this->storage->filesize($path);
$unencryptedSize = $this->filesize($path);
}
try {
if (
$mode === 'w'
|| $mode === 'w+'
|| $mode === 'wb'
|| $mode === 'wb+'
) {
if (!empty($encryptionModuleId)) {
$encryptionModule = $this->encryptionManager->getEncryptionModule($encryptionModuleId);
} else {
$encryptionModule = $this->encryptionManager->getDefaultEncryptionModule();
}
$shouldEncrypt = $encryptionModule->shouldEncrypt($fullPath);
} else {
// only get encryption module if we found one in the header
if (!empty($encryptionModuleId)) {
$encryptionModule = $this->encryptionManager->getEncryptionModule($encryptionModuleId);
$shouldEncrypt = true;
}
}
} catch (ModuleDoesNotExistsException $e) {
$this->logger->warning('Encryption module "' . $encryptionModuleId .
'" not found, file will be stored unencrypted');
}
// encryption disabled on write of new file and write to existing unencrypted file -> don't encrypt
$encEnabled = $this->encryptionManager->isEnabled();
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if (!$encEnabled || !$this->mount->getOption('encrypt', true)) {
if (!$targetExists || !$targetIsEncrypted) {
$shouldEncrypt = false;
}
}
if($shouldEncrypt === true && !$this->util->isExcluded($fullPath) && $encryptionModule !== null) {
$source = $this->storage->fopen($path, $mode);
$handle = \OC\Files\Stream\Encryption::wrap($source, $path, $fullPath, $header,
$this->uid, $encryptionModule, $this->storage, $this, $this->util, $this->fileHelper, $mode,
$size, $unencryptedSize);
return $handle;
} else {
return $this->storage->fopen($path, $mode);
}
}
/**
* get the path to a local version of the file.
* The local version of the file can be temporary and doesn't have to be persistent across requests
*
* @param string $path
* @return string
*/
public function getLocalFile($path) {
return $this->getCachedFile($path);
}
/**
* Returns the wrapped storage's value for isLocal()
*
* @return bool wrapped storage's isLocal() value
*/
public function isLocal() {
return false;
}
/**
* see http://php.net/manual/en/function.stat.php
* only the following keys are required in the result: size and mtime
*
* @param string $path
* @return array
*/
public function stat($path) {
$stat = $this->storage->stat($path);
$fileSize = $this->filesize($path);
$stat['size'] = $fileSize;
$stat[7] = $fileSize;
return $stat;
}
/**
* see http://php.net/manual/en/function.hash.php
*
* @param string $type
* @param string $path
* @param bool $raw
* @return string
*/
public function hash($type, $path, $raw = false) {
$fh = $this->fopen($path, 'rb');
$ctx = hash_init($type);
hash_update_stream($ctx, $fh);
fclose($fh);
return hash_final($ctx, $raw);
}
/**
* return full path, including mount point
*
* @param string $path relative to mount point
* @return string full path including mount point
*/
protected function getFullPath($path) {
return \OC\Files\Filesystem::normalizePath($this->mountPoint . '/' . $path);
}
/**
* read header from file
*
* @param string $path
* @return array
*/
protected function getHeader($path) {
$header = '';
if ($this->storage->file_exists($path)) {
$handle = $this->storage->fopen($path, 'r');
$header = fread($handle, $this->util->getHeaderSize());
fclose($handle);
}
return $this->util->readHeader($header);
}
/**
* read encryption module needed to read/write the file located at $path
*
* @param string $path
* @return null|\OCP\Encryption\IEncryptionModule
* @throws ModuleDoesNotExistsException
* @throws \Exception
*/
protected function getEncryptionModule($path) {
$encryptionModule = null;
$header = $this->getHeader($path);
$encryptionModuleId = $this->util->getEncryptionModuleId($header);
if (!empty($encryptionModuleId)) {
try {
$encryptionModule = $this->encryptionManager->getEncryptionModule($encryptionModuleId);
} catch (ModuleDoesNotExistsException $e) {
$this->logger->critical('Encryption module defined in "' . $path . '" not loaded!');
throw $e;
}
}
return $encryptionModule;
}
public function updateUnencryptedSize($path, $unencryptedSize) {
$this->unencryptedSize[$path] = $unencryptedSize;
}
/**
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* @param string $encryptionModuleId
* @return \OCP\Encryption\Keys\IStorage
*/
protected function getKeyStorage($encryptionModuleId) {
$keyStorage = \OC::$server->getEncryptionKeyStorage($encryptionModuleId);
return $keyStorage;
}
}