owncloud/core

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lib/private/Encryption/DecryptAll.php

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<?php
/**
 * @author Björn Schießle <bjoern@schiessle.org>
 * @author Christian Jürges <christian@eqipe.ch>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Vincent Petry <pvince81@owncloud.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @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\DecryptionFailedException;
use OC\Files\View;
use \OCP\Encryption\IEncryptionModule;
use OCP\ILogger;
use OCP\IUser;
use OCP\IUserManager;
use Symfony\Component\Console\Helper\ProgressBar;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

class DecryptAll {
    /** @var  OutputInterface */
    protected $output;

    /** @var  InputInterface */
    protected $input;

    /** @var  Manager */
    protected $encryptionManager;

    /** @var IUserManager */
    protected $userManager;

    /** @var View */
    protected $rootView;

    /** @var  array files which couldn't be decrypted */
    protected $failed;

    /** @var ILogger */
    protected $logger;

    /**
     * DecryptAll constructor.
     *
     * @param Manager $encryptionManager
     * @param IUserManager $userManager
     * @param View $rootView
     * @param ILogger $logger
     */
    public function __construct(
        Manager $encryptionManager,
        IUserManager $userManager,
        View $rootView,
        ILogger $logger
    ) {
        $this->encryptionManager = $encryptionManager;
        $this->userManager = $userManager;
        $this->rootView = $rootView;
        $this->failed = [];
        $this->logger = $logger;
    }

    /**
     * start to decrypt all files
     *
     * @param InputInterface $input
     * @param OutputInterface $output
     * @param string $user which users data folder should be decrypted, default = all users
     * @return bool
     * @throws \Exception
     */
    public function decryptAll(InputInterface $input, OutputInterface $output, $user = '') {
        $this->input = $input;
        $this->output = $output;

        if ($user !== '' && $this->userManager->userExists($user) === false) {
            $this->output->writeln('User "' . $user . '" does not exist. Please check the username and try again');
            return false;
        }

        $this->output->writeln('prepare encryption modules...');
        if (\OC::$server->getAppConfig()->getValue('encryption', 'useMasterKey', '0') !== '0') {
            if ($this->prepareEncryptionModules($user) === false) {
                return false;
            }
        }
        $this->output->writeln(' done.');

        $this->decryptAllUsersFiles($user);

        if (empty($this->failed)) {
            $this->output->writeln('all files could be decrypted successfully!');
        } else {
            $this->output->writeln('Files for following users couldn\'t be decrypted, ');
            $this->output->writeln('maybe the user is not set up in a way that supports this operation: ');
            foreach ($this->failed as $uid => $data) {
                $this->output->writeln('    ' . $uid);
                foreach ($data as $failure) {
                    $path = $failure['path'];
                    $message = $failure['exception']->getMessage();
                    $this->output->writeLn("           $path - $message");
                }
            }
            $this->output->writeln('');
        }

        return true;
    }

    /**
     * prepare encryption modules to perform the decrypt all function
     *
     * @param $user
     * @return bool
     */
    protected function prepareEncryptionModules($user) {
        // prepare all encryption modules for decrypt all
        $encryptionModules = $this->encryptionManager->getEncryptionModules();
        foreach ($encryptionModules as $moduleDesc) {
            /** @var IEncryptionModule $module */
            $module = \call_user_func($moduleDesc['callback']);
            $this->output->writeln('');
            $this->output->writeln('Prepare "' . $module->getDisplayName() . '"');
            $this->output->writeln('');
            if ($module->prepareDecryptAll($this->input, $this->output, $user) === false) {
                $this->output->writeln('Module "' . $moduleDesc['displayName'] . '" does not support the functionality to decrypt all files again or the initialization of the module failed!');
                return false;
            }
        }

        return true;
    }

    /**
     * iterate over all seen users and decrypt their files
     *
     * @param string $user which users files should be decrypted, default = all users
     * @return bool
     */
    protected function decryptAllUsersFiles($user = '') {
        $this->output->writeln("\n");

        $progress = new ProgressBar($this->output);
        $progress->setFormat(" %message% \n [%bar%]");
        $progress->start();
        $progress->setMessage("starting to decrypt files...");
        $progress->advance();

        if ($user === '') {
            $userNo = 1;
            $numberOfUsers = $this->userManager->countSeenUsers();
            if ($numberOfUsers === 0) {
                return false;
            }
            $this->userManager->callForSeenUsers(function (IUser $user) use ($progress, &$userNo, $numberOfUsers) {
                if (\OC::$server->getAppConfig()->getValue('encryption', 'userSpecificKey', '0') !== '0') {
                    if ($this->prepareEncryptionModules($user->getUID()) === false) {
                        return false;
                    }
                }
                $this->decryptUsersFiles(
                    $user->getUID(),
                    $progress,
                    "{$user->getUID()} ($userNo of $numberOfUsers)"
                );
                $userNo++;
            });
        } else {
            if (\OC::$server->getConfig()->getAppValue('encryption', 'userSpecificKey', '0') !== '0') {
                $userObject = $this->userManager->get($user);
                if ($userObject !== null) {
                    if ($this->prepareEncryptionModules($userObject->getUID()) === false) {
                        return false;
                    }
                }
            }
            $this->decryptUsersFiles($user, $progress, "$user (1 of 1)");
        }

        $this->output->writeln("\n\n");

        $progress->setMessage("starting to decrypt files... finished");
        $progress->finish();

        $this->output->writeln("\n\n");
        return true;
    }

    /**
     * encrypt files from the given user
     *
     * @param string $uid
     * @param ProgressBar $progress
     * @param string $userCount
     */
    protected function decryptUsersFiles($uid, ProgressBar $progress, $userCount) {
        $this->setupUserFS($uid);
        $directories = [];
        $directories[] = '/' . $uid . '/files';

        while ($root = \array_pop($directories)) {
            $content = $this->rootView->getDirectoryContent($root);
            foreach ($content as $file) {
                // only decrypt files owned by the user, exclude incoming local shares, and incoming federated shares
                if ($file->getStorage()->instanceOfStorage('\OCA\Files_Sharing\ISharedStorage')) {
                    continue;
                }
                $path = $root . '/' . $file['name'];
                if ($this->rootView->is_dir($path)) {
                    $directories[] = $path;
                    continue;
                } else {
                    try {
                        $progress->setMessage("decrypt files for user $userCount: $path");
                        $progress->advance();
                        if ($file->isEncrypted() === false) {
                            $progress->setMessage("decrypt files for user $userCount: $path (already decrypted)");
                            $progress->advance();
                        } else {
                            if ($this->decryptFile($path) === false) {
                                $progress->setMessage("decrypt files for user $userCount: $path (already decrypted)");
                                $progress->advance();
                            }
                        }
                    } catch (\Exception $e) {
                        $this->logger->logException($e, [
                            'message' => "Exception trying to decrypt file <$path> for user <$uid>",
                            'app' => __CLASS__
                        ]);
                        if (isset($this->failed[$uid])) {
                            $this->failed[$uid][] = ['path' => $path, 'exception' => $e];
                        } else {
                            $this->failed[$uid] = [['path' => $path, 'exception' => $e]];
                        }
                    }
                }
            }
        }
    }

    /**
     * encrypt file
     *
     * @param string $path
     * @return bool
     */
    protected function decryptFile($path) {
        $source = $path;
        $target = $path . '.decrypted.' . $this->getTimestamp() . '.part';

        try {
            \OC\Files\Storage\Wrapper\Encryption::setDisableWriteEncryption(true);
            $this->rootView->copy($source, $target);
            \OC\Files\Storage\Wrapper\Encryption::setDisableWriteEncryption(false);
            View::setIgnorePartFile(true);
            $this->rootView->rename($target, $source);
            View::setIgnorePartFile(false);
            list($storage, $internalPath) = $this->rootView->resolvePath($source);
            //Update the encrypted column in file cache to zero, as the file is decrypted
            $storage->getCache()->put($internalPath, ['encrypted' => 0]);
        } catch (DecryptionFailedException $e) {
            if ($this->rootView->file_exists($target)) {
                $this->rootView->unlink($target);
            }
            return false;
        }

        return true;
    }

    /**
     * get current timestamp
     *
     * @return int
     */
    protected function getTimestamp() {
        return \time();
    }

    /**
     * setup user file system
     *
     * @param string $uid
     */
    protected function setupUserFS($uid) {
        \OC_Util::tearDownFS();
        \OC_Util::setupFS($uid);
    }
}