nextcloud/lib/private/encryption/util.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\Encryption;
use OC\Encryption\Exceptions\EncryptionHeaderKeyExistsException;
use OC\Encryption\Exceptions\EncryptionHeaderToLargeException;
use OC\Encryption\Exceptions\ModuleDoesNotExistsException;
use OC\Files\Filesystem;
use OC\Files\View;
use OCP\Encryption\IEncryptionModule;
use OCP\IConfig;
class Util {
const HEADER_START = 'HBEGIN';
const HEADER_END = 'HEND';
const HEADER_PADDING_CHAR = '-';
const HEADER_ENCRYPTION_MODULE_KEY = 'oc_encryption_module';
/**
* block size will always be 8192 for a PHP stream
* @see https://bugs.php.net/bug.php?id=21641
* @var integer
*/
protected $headerSize = 8192;
/**
* block size will always be 8192 for a PHP stream
* @see https://bugs.php.net/bug.php?id=21641
* @var integer
*/
protected $blockSize = 8192;
/** @var View */
protected $view;
/** @var array */
protected $ocHeaderKeys;
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/** @var \OC\User\Manager */
protected $userManager;
/** @var IConfig */
protected $config;
/** @var array paths excluded from encryption */
protected $excludedPaths;
/** @var \OC\Group\Manager $manager */
protected $groupManager;
/**
*
* @param \OC\Files\View $view
* @param \OC\User\Manager $userManager
* @param \OC\Group\Manager $groupManager
* @param IConfig $config
*/
public function __construct(
\OC\Files\View $view,
\OC\User\Manager $userManager,
\OC\Group\Manager $groupManager,
IConfig $config) {
$this->ocHeaderKeys = [
self::HEADER_ENCRYPTION_MODULE_KEY
];
$this->view = $view;
$this->userManager = $userManager;
$this->groupManager = $groupManager;
$this->config = $config;
$this->excludedPaths[] = 'files_encryption';
}
/**
* read encryption module ID from header
*
* @param array $header
* @return string
* @throws ModuleDoesNotExistsException
*/
public function getEncryptionModuleId(array $header = null) {
$id = '';
$encryptionModuleKey = self::HEADER_ENCRYPTION_MODULE_KEY;
if (isset($header[$encryptionModuleKey])) {
$id = $header[$encryptionModuleKey];
} elseif (isset($header['cipher'])) {
if (class_exists('\OCA\Encryption\Crypto\Encryption')) {
// fall back to default encryption if the user migrated from
// ownCloud <= 8.0 with the old encryption
$id = \OCA\Encryption\Crypto\Encryption::ID;
} else {
throw new ModuleDoesNotExistsException('ownCloud default encryption module missing');
}
}
return $id;
}
/**
* read header into array
*
* @param string $header
* @return array
*/
public function readHeader($header) {
$result = array();
if (substr($header, 0, strlen(self::HEADER_START)) === self::HEADER_START) {
$endAt = strpos($header, self::HEADER_END);
if ($endAt !== false) {
$header = substr($header, 0, $endAt + strlen(self::HEADER_END));
// +1 to not start with an ':' which would result in empty element at the beginning
$exploded = explode(':', substr($header, strlen(self::HEADER_START)+1));
$element = array_shift($exploded);
while ($element !== self::HEADER_END) {
$result[$element] = array_shift($exploded);
$element = array_shift($exploded);
}
}
}
return $result;
}
/**
* create header for encrypted file
*
* @param array $headerData
* @param IEncryptionModule $encryptionModule
* @return string
* @throws EncryptionHeaderToLargeException if header has to many arguments
* @throws EncryptionHeaderKeyExistsException if header key is already in use
*/
public function createHeader(array $headerData, IEncryptionModule $encryptionModule) {
$header = self::HEADER_START . ':' . self::HEADER_ENCRYPTION_MODULE_KEY . ':' . $encryptionModule->getId() . ':';
foreach ($headerData as $key => $value) {
if (in_array($key, $this->ocHeaderKeys)) {
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throw new EncryptionHeaderKeyExistsException($key);
}
$header .= $key . ':' . $value . ':';
}
$header .= self::HEADER_END;
if (strlen($header) > $this->getHeaderSize()) {
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throw new EncryptionHeaderToLargeException();
}
$paddedHeader = str_pad($header, $this->headerSize, self::HEADER_PADDING_CHAR, STR_PAD_RIGHT);
return $paddedHeader;
}
/**
* go recursively through a dir and collect all files and sub files.
*
* @param string $dir relative to the users files folder
* @return array with list of files relative to the users files folder
*/
public function getAllFiles($dir) {
$result = array();
$dirList = array($dir);
while ($dirList) {
$dir = array_pop($dirList);
$content = $this->view->getDirectoryContent($dir);
foreach ($content as $c) {
if ($c->getType() === 'dir') {
$dirList[] = $c->getPath();
} else {
$result[] = $c->getPath();
}
}
}
return $result;
}
/**
* check if it is a file uploaded by the user stored in data/user/files
* or a metadata file
*
* @param string $path relative to the data/ folder
* @return boolean
*/
public function isFile($path) {
$parts = explode('/', Filesystem::normalizePath($path), 4);
if (isset($parts[2]) && $parts[2] === 'files') {
return true;
}
return false;
}
/**
* return size of encryption header
*
* @return integer
*/
public function getHeaderSize() {
return $this->headerSize;
}
/**
* return size of block read by a PHP stream
*
* @return integer
*/
public function getBlockSize() {
return $this->blockSize;
}
/**
* get the owner and the path for the file relative to the owners files folder
*
* @param string $path
* @return array
* @throws \BadMethodCallException
*/
public function getUidAndFilename($path) {
$parts = explode('/', $path);
$uid = '';
if (count($parts) > 2) {
$uid = $parts[1];
}
if (!$this->userManager->userExists($uid)) {
throw new \BadMethodCallException(
'path needs to be relative to the system wide data folder and point to a user specific file'
);
}
$ownerPath = implode('/', array_slice($parts, 2));
return array($uid, Filesystem::normalizePath($ownerPath));
}
/**
* Remove .path extension from a file path
* @param string $path Path that may identify a .part file
* @return string File path without .part extension
* @note this is needed for reusing keys
*/
public function stripPartialFileExtension($path) {
$extension = pathinfo($path, PATHINFO_EXTENSION);
if ( $extension === 'part') {
$newLength = strlen($path) - 5; // 5 = strlen(".part")
$fPath = substr($path, 0, $newLength);
// if path also contains a transaction id, we remove it too
$extension = pathinfo($fPath, PATHINFO_EXTENSION);
if(substr($extension, 0, 12) === 'ocTransferId') { // 12 = strlen("ocTransferId")
$newLength = strlen($fPath) - strlen($extension) -1;
$fPath = substr($fPath, 0, $newLength);
}
return $fPath;
} else {
return $path;
}
}
public function getUserWithAccessToMountPoint($users, $groups) {
$result = array();
if (in_array('all', $users)) {
$result = \OCP\User::getUsers();
} else {
$result = array_merge($result, $users);
foreach ($groups as $group) {
$result = array_merge($result, \OC_Group::usersInGroup($group));
}
}
return $result;
}
/**
* check if the file is stored on a system wide mount point
* @param string $path relative to /data/user with leading '/'
* @param string $uid
* @return boolean
*/
public function isSystemWideMountPoint($path, $uid) {
if (\OCP\App::isEnabled("files_external")) {
$mounts = \OC_Mount_Config::getSystemMountPoints();
foreach ($mounts as $mount) {
if (strpos($path, '/files/' . $mount['mountpoint']) === 0) {
if ($this->isMountPointApplicableToUser($mount, $uid)) {
return true;
}
}
}
}
return false;
}
/**
* check if mount point is applicable to user
*
* @param array $mount contains $mount['applicable']['users'], $mount['applicable']['groups']
* @param string $uid
* @return boolean
*/
private function isMountPointApplicableToUser($mount, $uid) {
$acceptedUids = array('all', $uid);
// check if mount point is applicable for the user
$intersection = array_intersect($acceptedUids, $mount['applicable']['users']);
if (!empty($intersection)) {
return true;
}
// check if mount point is applicable for group where the user is a member
foreach ($mount['applicable']['groups'] as $gid) {
if ($this->groupManager->isInGroup($uid, $gid)) {
return true;
}
}
return false;
}
/**
* check if it is a path which is excluded by ownCloud from encryption
*
* @param string $path
* @return boolean
*/
public function isExcluded($path) {
$normalizedPath = \OC\Files\Filesystem::normalizePath($path);
$root = explode('/', $normalizedPath, 4);
if (count($root) > 1) {
//detect system wide folders
if (in_array($root[1], $this->excludedPaths)) {
return true;
}
// detect user specific folders
if ($this->userManager->userExists($root[1])
&& in_array($root[2], $this->excludedPaths)) {
return true;
}
}
return false;
}
/**
* check if recovery key is enabled for user
*
* @param string $uid
* @return boolean
*/
public function recoveryEnabled($uid) {
$enabled = $this->config->getUserValue($uid, 'encryption', 'recovery_enabled', '0');
return ($enabled === '1') ? true : false;
}
}