nextcloud/lib/private/Files/Storage/Wrapper/Encryption.php

994 lines
29 KiB
PHP

<?php
/**
* @author Björn Schießle <bjoern@schiessle.org>
* @author Joas Schilling <nickvergessen@owncloud.com>
* @author Lukas Reschke <lukas@statuscode.ch>
* @author Robin Appelman <icewind@owncloud.com>
* @author Thomas Müller <thomas.mueller@tmit.eu>
* @author Vincent Petry <pvince81@owncloud.com>
*
* @copyright Copyright (c) 2016, 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\Encryption\Update;
use OC\Encryption\Util;
use OC\Files\Cache\CacheEntry;
use OC\Files\Filesystem;
use OC\Files\Mount\Manager;
use OC\Files\Storage\LocalTempFileTrait;
use OC\Memcache\ArrayCache;
use OCP\Encryption\Exceptions\GenericEncryptionException;
use OCP\Encryption\IFile;
use OCP\Encryption\IManager;
use OCP\Encryption\Keys\IStorage;
use OCP\Files\Mount\IMountPoint;
use OCP\Files\Storage;
use OCP\ILogger;
use OCP\Files\Cache\ICacheEntry;
class Encryption extends Wrapper {
use LocalTempFileTrait;
/** @var string */
private $mountPoint;
/** @var \OC\Encryption\Util */
private $util;
/** @var \OCP\Encryption\IManager */
private $encryptionManager;
/** @var \OCP\ILogger */
private $logger;
/** @var string */
private $uid;
/** @var array */
protected $unencryptedSize;
/** @var \OCP\Encryption\IFile */
private $fileHelper;
/** @var IMountPoint */
private $mount;
/** @var IStorage */
private $keyStorage;
/** @var Update */
private $update;
/** @var Manager */
private $mountManager;
/** @var array remember for which path we execute the repair step to avoid recursions */
private $fixUnencryptedSizeOf = array();
/** @var ArrayCache */
private $arrayCache;
/**
* @param array $parameters
* @param IManager $encryptionManager
* @param Util $util
* @param ILogger $logger
* @param IFile $fileHelper
* @param string $uid
* @param IStorage $keyStorage
* @param Update $update
* @param Manager $mountManager
* @param ArrayCache $arrayCache
*/
public function __construct(
$parameters,
IManager $encryptionManager = null,
Util $util = null,
ILogger $logger = null,
IFile $fileHelper = null,
$uid = null,
IStorage $keyStorage = null,
Update $update = null,
Manager $mountManager = null,
ArrayCache $arrayCache = null
) {
$this->mountPoint = $parameters['mountPoint'];
$this->mount = $parameters['mount'];
$this->encryptionManager = $encryptionManager;
$this->util = $util;
$this->logger = $logger;
$this->uid = $uid;
$this->fileHelper = $fileHelper;
$this->keyStorage = $keyStorage;
$this->unencryptedSize = array();
$this->update = $update;
$this->mountManager = $mountManager;
$this->arrayCache = $arrayCache;
parent::__construct($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);
/** @var CacheEntry $info */
$info = $this->getCache()->get($path);
if (isset($this->unencryptedSize[$fullPath])) {
$size = $this->unencryptedSize[$fullPath];
// update file cache
if ($info instanceof ICacheEntry) {
$info = $info->getData();
$info['encrypted'] = $info['encryptedVersion'];
} else {
if (!is_array($info)) {
$info = [];
}
$info['encrypted'] = true;
}
$info['size'] = $size;
$this->getCache()->put($path, $info);
return $size;
}
if (isset($info['fileid']) && $info['encrypted']) {
return $this->verifyUnencryptedSize($path, $info['size']);
}
return $this->storage->filesize($path);
}
/**
* @param string $path
* @return array
*/
public function getMetaData($path) {
$data = $this->storage->getMetaData($path);
if (is_null($data)) {
return null;
}
$fullPath = $this->getFullPath($path);
$info = $this->getCache()->get($path);
if (isset($this->unencryptedSize[$fullPath])) {
$data['encrypted'] = true;
$data['size'] = $this->unencryptedSize[$fullPath];
} else {
if (isset($info['fileid']) && $info['encrypted']) {
$data['size'] = $this->verifyUnencryptedSize($path, $info['size']);
$data['encrypted'] = true;
}
}
if (isset($info['encryptedVersion']) && $info['encryptedVersion'] > 1) {
$data['encryptedVersion'] = $info['encryptedVersion'];
}
return $data;
}
/**
* 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');
if (is_resource($handle)) {
$written = fwrite($handle, $data);
fclose($handle);
return $written;
}
return false;
}
/**
* see http://php.net/manual/en/function.unlink.php
*
* @param string $path
* @return bool
*/
public function unlink($path) {
$fullPath = $this->getFullPath($path);
if ($this->util->isExcluded($fullPath)) {
return $this->storage->unlink($path);
}
$encryptionModule = $this->getEncryptionModule($path);
if ($encryptionModule) {
$this->keyStorage->deleteAllFileKeys($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) {
$result = $this->storage->rename($path1, $path2);
if ($result &&
// versions always use the keys from the original file, so we can skip
// this step for versions
$this->isVersion($path2) === false &&
$this->encryptionManager->isEnabled()) {
$source = $this->getFullPath($path1);
if (!$this->util->isExcluded($source)) {
$target = $this->getFullPath($path2);
if (isset($this->unencryptedSize[$source])) {
$this->unencryptedSize[$target] = $this->unencryptedSize[$source];
}
$this->keyStorage->renameKeys($source, $target);
$module = $this->getEncryptionModule($path2);
if ($module) {
$module->update($target, $this->uid, []);
}
}
}
return $result;
}
/**
* see http://php.net/manual/en/function.rmdir.php
*
* @param string $path
* @return bool
*/
public function rmdir($path) {
$result = $this->storage->rmdir($path);
$fullPath = $this->getFullPath($path);
if ($result &&
$this->util->isExcluded($fullPath) === false &&
$this->encryptionManager->isEnabled()
) {
$this->keyStorage->deleteAllFileKeys($fullPath);
}
return $result;
}
/**
* check if a file can be read
*
* @param string $path
* @return bool
*/
public function isReadable($path) {
$isReadable = true;
$metaData = $this->getMetaData($path);
if (
!$this->is_dir($path) &&
isset($metaData['encrypted']) &&
$metaData['encrypted'] === true
) {
$fullPath = $this->getFullPath($path);
$module = $this->getEncryptionModule($path);
$isReadable = $module->isReadable($fullPath, $this->uid);
}
return $this->storage->isReadable($path) && $isReadable;
}
/**
* see http://php.net/manual/en/function.copy.php
*
* @param string $path1
* @param string $path2
* @return bool
*/
public function copy($path1, $path2) {
$source = $this->getFullPath($path1);
if ($this->util->isExcluded($source)) {
return $this->storage->copy($path1, $path2);
}
// need to stream copy file by file in case we copy between a encrypted
// and a unencrypted storage
$this->unlink($path2);
$result = $this->copyFromStorage($this, $path1, $path2);
return $result;
}
/**
* see http://php.net/manual/en/function.fopen.php
*
* @param string $path
* @param string $mode
* @return resource|bool
* @throws GenericEncryptionException
* @throws ModuleDoesNotExistsException
*/
public function fopen($path, $mode) {
// check if the file is stored in the array cache, this means that we
// copy a file over to the versions folder, in this case we don't want to
// decrypt it
if ($this->arrayCache->hasKey('encryption_copy_version_' . $path)) {
$this->arrayCache->remove('encryption_copy_version_' . $path);
return $this->storage->fopen($path, $mode);
}
$encryptionEnabled = $this->encryptionManager->isEnabled();
$shouldEncrypt = false;
$encryptionModule = null;
$header = $this->getHeader($path);
$signed = (isset($header['signed']) && $header['signed'] === 'true') ? true : false;
$fullPath = $this->getFullPath($path);
$encryptionModuleId = $this->util->getEncryptionModuleId($header);
if ($this->util->isExcluded($fullPath) === false) {
$size = $unencryptedSize = 0;
$realFile = $this->util->stripPartialFileExtension($path);
$targetExists = $this->file_exists($realFile) || $this->file_exists($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);
}
if ($this->file_exists($path)) {
$size = $this->storage->filesize($path);
$unencryptedSize = $this->filesize($path);
} else {
$size = $unencryptedSize = 0;
}
}
try {
if (
$mode === 'w'
|| $mode === 'w+'
|| $mode === 'wb'
|| $mode === 'wb+'
) {
// don't overwrite encrypted files if encryption is not enabled
if ($targetIsEncrypted && $encryptionEnabled === false) {
throw new GenericEncryptionException('Tried to access encrypted file but encryption is not enabled');
}
if ($encryptionEnabled) {
// if $encryptionModuleId is empty, the default module will be used
$encryptionModule = $this->encryptionManager->getEncryptionModule($encryptionModuleId);
$shouldEncrypt = $encryptionModule->shouldEncrypt($fullPath);
$signed = true;
}
} else {
$info = $this->getCache()->get($path);
// only get encryption module if we found one in the header
// or if file should be encrypted according to the file cache
if (!empty($encryptionModuleId)) {
$encryptionModule = $this->encryptionManager->getEncryptionModule($encryptionModuleId);
$shouldEncrypt = true;
} else if (empty($encryptionModuleId) && $info['encrypted'] === true) {
// we come from a old installation. No header and/or no module defined
// but the file is encrypted. In this case we need to use the
// OC_DEFAULT_MODULE to read the file
$encryptionModule = $this->encryptionManager->getEncryptionModule('OC_DEFAULT_MODULE');
$shouldEncrypt = true;
$targetIsEncrypted = true;
}
}
} catch (ModuleDoesNotExistsException $e) {
$this->logger->warning('Encryption module "' . $encryptionModuleId .
'" not found, file will be stored unencrypted (' . $e->getMessage() . ')');
}
// encryption disabled on write of new file and write to existing unencrypted file -> don't encrypt
if (!$encryptionEnabled || !$this->mount->getOption('encrypt', true)) {
if (!$targetExists || !$targetIsEncrypted) {
$shouldEncrypt = false;
}
}
if ($shouldEncrypt === true && $encryptionModule !== null) {
$headerSize = $this->getHeaderSize($path);
$source = $this->storage->fopen($path, $mode);
if (!is_resource($source)) {
return false;
}
$handle = \OC\Files\Stream\Encryption::wrap($source, $path, $fullPath, $header,
$this->uid, $encryptionModule, $this->storage, $this, $this->util, $this->fileHelper, $mode,
$size, $unencryptedSize, $headerSize, $signed);
return $handle;
}
}
return $this->storage->fopen($path, $mode);
}
/**
* perform some plausibility checks if the the unencrypted size is correct.
* If not, we calculate the correct unencrypted size and return it
*
* @param string $path internal path relative to the storage root
* @param int $unencryptedSize size of the unencrypted file
*
* @return int unencrypted size
*/
protected function verifyUnencryptedSize($path, $unencryptedSize) {
$size = $this->storage->filesize($path);
$result = $unencryptedSize;
if ($unencryptedSize < 0 ||
($size > 0 && $unencryptedSize === $size)
) {
// check if we already calculate the unencrypted size for the
// given path to avoid recursions
if (isset($this->fixUnencryptedSizeOf[$this->getFullPath($path)]) === false) {
$this->fixUnencryptedSizeOf[$this->getFullPath($path)] = true;
try {
$result = $this->fixUnencryptedSize($path, $size, $unencryptedSize);
} catch (\Exception $e) {
$this->logger->error('Couldn\'t re-calculate unencrypted size for '. $path);
$this->logger->logException($e);
}
unset($this->fixUnencryptedSizeOf[$this->getFullPath($path)]);
}
}
return $result;
}
/**
* calculate the unencrypted size
*
* @param string $path internal path relative to the storage root
* @param int $size size of the physical file
* @param int $unencryptedSize size of the unencrypted file
*
* @return int calculated unencrypted size
*/
protected function fixUnencryptedSize($path, $size, $unencryptedSize) {
$headerSize = $this->getHeaderSize($path);
$header = $this->getHeader($path);
$encryptionModule = $this->getEncryptionModule($path);
$stream = $this->storage->fopen($path, 'r');
// if we couldn't open the file we return the old unencrypted size
if (!is_resource($stream)) {
$this->logger->error('Could not open ' . $path . '. Recalculation of unencrypted size aborted.');
return $unencryptedSize;
}
$newUnencryptedSize = 0;
$size -= $headerSize;
$blockSize = $this->util->getBlockSize();
// if a header exists we skip it
if ($headerSize > 0) {
fread($stream, $headerSize);
}
// fast path, else the calculation for $lastChunkNr is bogus
if ($size === 0) {
return 0;
}
$signed = (isset($header['signed']) && $header['signed'] === 'true') ? true : false;
$unencryptedBlockSize = $encryptionModule->getUnencryptedBlockSize($signed);
// calculate last chunk nr
// next highest is end of chunks, one subtracted is last one
// we have to read the last chunk, we can't just calculate it (because of padding etc)
$lastChunkNr = ceil($size/ $blockSize)-1;
// calculate last chunk position
$lastChunkPos = ($lastChunkNr * $blockSize);
// try to fseek to the last chunk, if it fails we have to read the whole file
if (@fseek($stream, $lastChunkPos, SEEK_CUR) === 0) {
$newUnencryptedSize += $lastChunkNr * $unencryptedBlockSize;
}
$lastChunkContentEncrypted='';
$count = $blockSize;
while ($count > 0) {
$data=fread($stream, $blockSize);
$count=strlen($data);
$lastChunkContentEncrypted .= $data;
if(strlen($lastChunkContentEncrypted) > $blockSize) {
$newUnencryptedSize += $unencryptedBlockSize;
$lastChunkContentEncrypted=substr($lastChunkContentEncrypted, $blockSize);
}
}
fclose($stream);
// we have to decrypt the last chunk to get it actual size
$encryptionModule->begin($this->getFullPath($path), $this->uid, 'r', $header, []);
$decryptedLastChunk = $encryptionModule->decrypt($lastChunkContentEncrypted, $lastChunkNr . 'end');
$decryptedLastChunk .= $encryptionModule->end($this->getFullPath($path), $lastChunkNr . 'end');
// calc the real file size with the size of the last chunk
$newUnencryptedSize += strlen($decryptedLastChunk);
$this->updateUnencryptedSize($this->getFullPath($path), $newUnencryptedSize);
// write to cache if applicable
$cache = $this->storage->getCache();
if ($cache) {
$entry = $cache->get($path);
$cache->update($entry['fileid'], ['size' => $newUnencryptedSize]);
}
return $newUnencryptedSize;
}
/**
* @param Storage $sourceStorage
* @param string $sourceInternalPath
* @param string $targetInternalPath
* @param bool $preserveMtime
* @return bool
*/
public function moveFromStorage(Storage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = true) {
if ($sourceStorage === $this) {
return $this->rename($sourceInternalPath, $targetInternalPath);
}
// TODO clean this up once the underlying moveFromStorage in OC\Files\Storage\Wrapper\Common is fixed:
// - call $this->storage->moveFromStorage() instead of $this->copyBetweenStorage
// - copy the file cache update from $this->copyBetweenStorage to this method
// - copy the copyKeys() call from $this->copyBetweenStorage to this method
// - remove $this->copyBetweenStorage
if (!$sourceStorage->isDeletable($sourceInternalPath)) {
return false;
}
$result = $this->copyBetweenStorage($sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime, true);
if ($result) {
if ($sourceStorage->is_dir($sourceInternalPath)) {
$result &= $sourceStorage->rmdir($sourceInternalPath);
} else {
$result &= $sourceStorage->unlink($sourceInternalPath);
}
}
return $result;
}
/**
* @param Storage $sourceStorage
* @param string $sourceInternalPath
* @param string $targetInternalPath
* @param bool $preserveMtime
* @param bool $isRename
* @return bool
*/
public function copyFromStorage(Storage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false, $isRename = false) {
// TODO clean this up once the underlying moveFromStorage in OC\Files\Storage\Wrapper\Common is fixed:
// - call $this->storage->copyFromStorage() instead of $this->copyBetweenStorage
// - copy the file cache update from $this->copyBetweenStorage to this method
// - copy the copyKeys() call from $this->copyBetweenStorage to this method
// - remove $this->copyBetweenStorage
return $this->copyBetweenStorage($sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime, $isRename);
}
/**
* Update the encrypted cache version in the database
*
* @param Storage $sourceStorage
* @param string $sourceInternalPath
* @param string $targetInternalPath
* @param bool $isRename
*/
private function updateEncryptedVersion(Storage $sourceStorage, $sourceInternalPath, $targetInternalPath, $isRename) {
$isEncrypted = $this->encryptionManager->isEnabled() && $this->mount->getOption('encrypt', true) ? 1 : 0;
$cacheInformation = [
'encrypted' => (bool)$isEncrypted,
];
if($isEncrypted === 1) {
$encryptedVersion = $sourceStorage->getCache()->get($sourceInternalPath)['encryptedVersion'];
// In case of a move operation from an unencrypted to an encrypted
// storage the old encrypted version would stay with "0" while the
// correct value would be "1". Thus we manually set the value to "1"
// for those cases.
// See also https://github.com/owncloud/core/issues/23078
if($encryptedVersion === 0) {
$encryptedVersion = 1;
}
$cacheInformation['encryptedVersion'] = $encryptedVersion;
}
// in case of a rename we need to manipulate the source cache because
// this information will be kept for the new target
if ($isRename) {
$sourceStorage->getCache()->put($sourceInternalPath, $cacheInformation);
} else {
$this->getCache()->put($targetInternalPath, $cacheInformation);
}
}
/**
* copy file between two storages
*
* @param Storage $sourceStorage
* @param string $sourceInternalPath
* @param string $targetInternalPath
* @param bool $preserveMtime
* @param bool $isRename
* @return bool
* @throws \Exception
*/
private function copyBetweenStorage(Storage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime, $isRename) {
// for versions we have nothing to do, because versions should always use the
// key from the original file. Just create a 1:1 copy and done
if ($this->isVersion($targetInternalPath) ||
$this->isVersion($sourceInternalPath)) {
// remember that we try to create a version so that we can detect it during
// fopen($sourceInternalPath) and by-pass the encryption in order to
// create a 1:1 copy of the file
$this->arrayCache->set('encryption_copy_version_' . $sourceInternalPath, true);
$result = $this->storage->copyFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
$this->arrayCache->remove('encryption_copy_version_' . $sourceInternalPath);
if ($result) {
$info = $this->getCache('', $sourceStorage)->get($sourceInternalPath);
// make sure that we update the unencrypted size for the version
if (isset($info['encrypted']) && $info['encrypted'] === true) {
$this->updateUnencryptedSize(
$this->getFullPath($targetInternalPath),
$info['size']
);
}
$this->updateEncryptedVersion($sourceStorage, $sourceInternalPath, $targetInternalPath, $isRename);
}
return $result;
}
// first copy the keys that we reuse the existing file key on the target location
// and don't create a new one which would break versions for example.
$mount = $this->mountManager->findByStorageId($sourceStorage->getId());
if (count($mount) === 1) {
$mountPoint = $mount[0]->getMountPoint();
$source = $mountPoint . '/' . $sourceInternalPath;
$target = $this->getFullPath($targetInternalPath);
$this->copyKeys($source, $target);
} else {
$this->logger->error('Could not find mount point, can\'t keep encryption keys');
}
if ($sourceStorage->is_dir($sourceInternalPath)) {
$dh = $sourceStorage->opendir($sourceInternalPath);
$result = $this->mkdir($targetInternalPath);
if (is_resource($dh)) {
while ($result and ($file = readdir($dh)) !== false) {
if (!Filesystem::isIgnoredDir($file)) {
$result &= $this->copyFromStorage($sourceStorage, $sourceInternalPath . '/' . $file, $targetInternalPath . '/' . $file, false, $isRename);
}
}
}
} else {
try {
$source = $sourceStorage->fopen($sourceInternalPath, 'r');
$target = $this->fopen($targetInternalPath, 'w');
list(, $result) = \OC_Helper::streamCopy($source, $target);
fclose($source);
fclose($target);
} catch (\Exception $e) {
fclose($source);
fclose($target);
throw $e;
}
if($result) {
if ($preserveMtime) {
$this->touch($targetInternalPath, $sourceStorage->filemtime($sourceInternalPath));
}
$this->updateEncryptedVersion($sourceStorage, $sourceInternalPath, $targetInternalPath, $isRename);
} else {
// delete partially written target file
$this->unlink($targetInternalPath);
// delete cache entry that was created by fopen
$this->getCache()->remove($targetInternalPath);
}
}
return (bool)$result;
}
/**
* 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) {
if ($this->encryptionManager->isEnabled()) {
$cachedFile = $this->getCachedFile($path);
if (is_string($cachedFile)) {
return $cachedFile;
}
}
return $this->storage->getLocalFile($path);
}
/**
* Returns the wrapped storage's value for isLocal()
*
* @return bool wrapped storage's isLocal() value
*/
public function isLocal() {
if ($this->encryptionManager->isEnabled()) {
return false;
}
return $this->storage->isLocal();
}
/**
* 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 Filesystem::normalizePath($this->mountPoint . '/' . $path);
}
/**
* read first block of encrypted file, typically this will contain the
* encryption header
*
* @param string $path
* @return string
*/
protected function readFirstBlock($path) {
$firstBlock = '';
if ($this->storage->file_exists($path)) {
$handle = $this->storage->fopen($path, 'r');
$firstBlock = fread($handle, $this->util->getHeaderSize());
fclose($handle);
}
return $firstBlock;
}
/**
* return header size of given file
*
* @param string $path
* @return int
*/
protected function getHeaderSize($path) {
$headerSize = 0;
$realFile = $this->util->stripPartialFileExtension($path);
if ($this->storage->file_exists($realFile)) {
$path = $realFile;
}
$firstBlock = $this->readFirstBlock($path);
if (substr($firstBlock, 0, strlen(Util::HEADER_START)) === Util::HEADER_START) {
$headerSize = $this->util->getHeaderSize();
}
return $headerSize;
}
/**
* parse raw header to array
*
* @param string $rawHeader
* @return array
*/
protected function parseRawHeader($rawHeader) {
$result = array();
if (substr($rawHeader, 0, strlen(Util::HEADER_START)) === Util::HEADER_START) {
$header = $rawHeader;
$endAt = strpos($header, Util::HEADER_END);
if ($endAt !== false) {
$header = substr($header, 0, $endAt + strlen(Util::HEADER_END));
// +1 to not start with an ':' which would result in empty element at the beginning
$exploded = explode(':', substr($header, strlen(Util::HEADER_START)+1));
$element = array_shift($exploded);
while ($element !== Util::HEADER_END) {
$result[$element] = array_shift($exploded);
$element = array_shift($exploded);
}
}
}
return $result;
}
/**
* read header from file
*
* @param string $path
* @return array
*/
protected function getHeader($path) {
$realFile = $this->util->stripPartialFileExtension($path);
if ($this->storage->file_exists($realFile)) {
$path = $realFile;
}
$firstBlock = $this->readFirstBlock($path);
$result = $this->parseRawHeader($firstBlock);
// if the header doesn't contain a encryption module we check if it is a
// legacy file. If true, we add the default encryption module
if (!isset($result[Util::HEADER_ENCRYPTION_MODULE_KEY])) {
if (!empty($result)) {
$result[Util::HEADER_ENCRYPTION_MODULE_KEY] = 'OC_DEFAULT_MODULE';
} else {
// if the header was empty we have to check first if it is a encrypted file at all
$info = $this->getCache()->get($path);
if (isset($info['encrypted']) && $info['encrypted'] === true) {
$result[Util::HEADER_ENCRYPTION_MODULE_KEY] = 'OC_DEFAULT_MODULE';
}
}
}
return $result;
}
/**
* 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;
}
/**
* @param string $path
* @param int $unencryptedSize
*/
public function updateUnencryptedSize($path, $unencryptedSize) {
$this->unencryptedSize[$path] = $unencryptedSize;
}
/**
* copy keys to new location
*
* @param string $source path relative to data/
* @param string $target path relative to data/
* @return bool
*/
protected function copyKeys($source, $target) {
if (!$this->util->isExcluded($source)) {
return $this->keyStorage->copyKeys($source, $target);
}
return false;
}
/**
* check if path points to a files version
*
* @param $path
* @return bool
*/
protected function isVersion($path) {
$normalized = Filesystem::normalizePath($path);
return substr($normalized, 0, strlen('/files_versions/')) === '/files_versions/';
}
}