owncloud/core

<?php
/**
 * @author Joas Schilling <coding@schilljs.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @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\Repair;

use OCP\Migration\IOutput;
use OCP\Migration\IRepairStep;
use Doctrine\DBAL\Platforms\OraclePlatform;

/**
 * Repairs shares with invalid data
 */
class RepairInvalidShares implements IRepairStep {
    public const CHUNK_SIZE = 200;

    /** @var \OCP\IConfig */
    protected $config;

    /** @var \OCP\IDBConnection */
    protected $connection;

    /**
     * @param \OCP\IConfig $config
     * @param \OCP\IDBConnection $connection
     */
    public function __construct($config, $connection) {
        $this->connection = $connection;
        $this->config = $config;
    }

    public function getName() {
        return 'Repair invalid shares';
    }

    /**
     * Past bugs would make it possible to set an expiration date on user shares even
     * though it is not supported. This functions removes the expiration date from such entries.
     */
    private function removeExpirationDateFromNonLinkShares(IOutput $out) {
        $builder = $this->connection->getQueryBuilder();
        $builder
            ->update('share')
            ->set('expiration', 'null')
            ->where($builder->expr()->isNotNull('expiration'))
            ->andWhere($builder->expr()->neq('share_type', $builder->expr()->literal(\OC\Share\Constants::SHARE_TYPE_LINK)));

        $updatedEntries = $builder->execute();
        if ($updatedEntries > 0) {
            $out->info('Removed invalid expiration date from ' . $updatedEntries . ' shares');
        }
    }

    /**
     * In the past link shares with public upload enabled were missing the delete permission.
     */
    private function addShareLinkDeletePermission(IOutput $out) {
        $oldPerms = \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_CREATE | \OCP\Constants::PERMISSION_UPDATE;
        $newPerms = \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_CREATE | \OCP\Constants::PERMISSION_UPDATE | \OCP\Constants::PERMISSION_DELETE;
        $builder = $this->connection->getQueryBuilder();
        $builder
            ->update('share')
            ->set('permissions', $builder->expr()->literal($newPerms))
            ->where($builder->expr()->eq('share_type', $builder->expr()->literal(\OC\Share\Constants::SHARE_TYPE_LINK)))
            ->andWhere($builder->expr()->eq('permissions', $builder->expr()->literal($oldPerms)));

        $updatedEntries = $builder->execute();
        if ($updatedEntries > 0) {
            $out->info('Fixed link share permissions for ' . $updatedEntries . ' shares');
        }
    }

    /**
     * Adjust file share permissions
     */
    private function adjustFileSharePermissions(IOutput $out) {
        $mask = \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_UPDATE | \OCP\Constants::PERMISSION_SHARE;
        $builder = $this->connection->getQueryBuilder();

        if ($this->connection->getDatabasePlatform() instanceof OraclePlatform) {
            $permsFunc = $builder->createFunction(
                'bitand(' . $builder->getColumnName('permissions') . ', ' . $mask . ')'
            );
        } else {
            $permsFunc = $builder->createFunction(
                '(' . $builder->getColumnName('permissions') . ' & ' . $mask . ')'
            );
        }
        $builder
            ->update('share')
            ->set('permissions', $permsFunc)
            ->where($builder->expr()->eq('item_type', $builder->expr()->literal('file')))
            ->andWhere($builder->expr()->neq('permissions', $permsFunc));

        $updatedEntries = $builder->execute();
        if ($updatedEntries > 0) {
            $out->info('Fixed file share permissions for ' . $updatedEntries . ' shares');
        }
    }

    /**
     * Remove shares where the parent share does not exist anymore
     */
    private function removeSharesNonExistingParent(IOutput $out) {
        $deletedEntries = 0;

        $query = $this->connection->getQueryBuilder();
        $query->select('s1.parent')
            ->from('share', 's1')
            ->where($query->expr()->isNotNull('s1.parent'))
                ->andWhere($query->expr()->isNull('s2.id'))
            ->leftJoin('s1', 'share', 's2', $query->expr()->eq('s1.parent', 's2.id'))
            ->groupBy('s1.parent')
            ->setMaxResults(self::CHUNK_SIZE);

        $deleteQuery = $this->connection->getQueryBuilder();
        $deleteQuery->delete('share')
            ->where($deleteQuery->expr()->eq('parent', $deleteQuery->createParameter('parent')));

        $deletedInLastChunk = self::CHUNK_SIZE;
        while ($deletedInLastChunk === self::CHUNK_SIZE) {
            $deletedInLastChunk = 0;
            $result = $query->execute();
            while ($row = $result->fetch()) {
                $deletedInLastChunk++;
                $deletedEntries += $deleteQuery->setParameter('parent', (int) $row['parent'])
                    ->execute();
            }
            $result->closeCursor();
        }

        if ($deletedEntries) {
            $out->info('Removed ' . $deletedEntries . ' shares where the parent did not exist');
        }
    }

    public function run(IOutput $out) {
        $ocVersionFromBeforeUpdate = $this->config->getSystemValue('version', '0.0.0');
        if (\version_compare($ocVersionFromBeforeUpdate, '8.2.0.7', '<')) {
            // this situation was only possible before 8.2
            $this->removeExpirationDateFromNonLinkShares($out);
        }
        if (\version_compare($ocVersionFromBeforeUpdate, '9.1.0.9', '<')) {
            // this situation was only possible before 9.1
            $this->addShareLinkDeletePermission($out);
        }
        if (\version_compare($ocVersionFromBeforeUpdate, '9.2.0.2', '<')) {
            $this->adjustFileSharePermissions($out);
        }

        $this->removeSharesNonExistingParent($out);
    }
}