FileMetadataPermissionsAspect.php

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<?php
namespace TYPO3\CMS\Core\Resource\Security;

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

use TYPO3\CMS\Backend\Utility\BackendUtility;
use TYPO3\CMS\Core\DataHandling\DataHandler;
use TYPO3\CMS\Core\DataHandling\DataHandlerCheckModifyAccessListHookInterface;
use TYPO3\CMS\Core\Resource\ResourceFactory;
use TYPO3\CMS\Core\SingletonInterface;
use TYPO3\CMS\Core\Utility\MathUtility;

class FileMetadataPermissionsAspect implements DataHandlerCheckModifyAccessListHookInterface, SingletonInterface {

    public function checkRecordUpdateAccess($table, $id, $fileMetadataRecord, $otherHookGrantedAccess, DataHandler $dataHandler) {
        $accessAllowed = $otherHookGrantedAccess;
        if ($table === 'sys_file_metadata' && $accessAllowed !== 0) {
            $existingFileMetadataRecord = BackendUtility::getRecord('sys_file_metadata', $id);
            if ($existingFileMetadataRecord === NULL || (empty($existingFileMetadataRecord['file']) && !empty($fileMetadataRecord['file']))) {
                $existingFileMetadataRecord = $fileMetadataRecord;
            }
            $accessAllowed = $this->checkFileWriteAccessForFileMetaData($existingFileMetadataRecord) ? 1 : 0;
        }

        return $accessAllowed;
    }

    public function checkModifyAccessList(&$accessAllowed, $table, DataHandler $parent) {
        if ($table === 'sys_file_metadata') {
            if (isset($parent->cmdmap[$table]) && is_array($parent->cmdmap[$table])) {
                foreach ($parent->cmdmap[$table] as $id => $command) {
                    if (empty($id) || !MathUtility::canBeInterpretedAsInteger($id)) {
                        throw new \UnexpectedValueException(
                            'Integer expected for data manipulation command.
                            This can only happen in the case of an attack attempt or when something went horribly wrong.
                            To not compromise security, we exit here.',
                            1399982816
                        );
                    }

                    $fileMetadataRecord = BackendUtility::getRecord('sys_file_metadata', $id);
                    $accessAllowed = $this->checkFileWriteAccessForFileMetaData($fileMetadataRecord);
                    if (!$accessAllowed) {
                        // If for any item in the array, access is not allowed, we deny the whole operation
                        break;
                    }
                }
            }

            if (isset($parent->datamap[$table]) && is_array($parent->datamap[$table])) {
                foreach ($parent->datamap[$table] as $id => $data) {

                    $recordAccessAllowed = FALSE;

                    if (strpos($id, 'NEW') === FALSE) {
                        $fileMetadataRecord = BackendUtility::getRecord('sys_file_metadata', $id);
                        if ($fileMetadataRecord !== NULL) {
                            if ($parent->isImporting && empty($fileMetadataRecord['file'])) {
                                // when importing the record was added with an empty file relation as first step
                                $recordAccessAllowed = TRUE;
                            } else {
                                $recordAccessAllowed = $this->checkFileWriteAccessForFileMetaData($fileMetadataRecord);
                            }
                        }
                    } else {
                        // for new records record access is allowed
                        $recordAccessAllowed = TRUE;
                    }

                    if (isset($data['file'])) {
                        if ($parent->isImporting && empty($data['file'])) {
                            // when importing the record will be created with an empty file relation as first step
                            $dataAccessAllowed = TRUE;
                        } elseif (empty($data['file'])) {
                            $dataAccessAllowed = FALSE;
                        } else {
                            $dataAccessAllowed = $this->checkFileWriteAccessForFileMetaData($data);
                        }
                    } else {
                        $dataAccessAllowed = TRUE;
                    }

                    if (!$recordAccessAllowed || !$dataAccessAllowed) {
                        // If for any item in the array, access is not allowed, we deny the whole operation
                        $accessAllowed = FALSE;
                        break;
                    }
                }
            }
        }
    }

    public function isAllowedToShowEditForm(array $parameters) {
        $table = $parameters['table'];
        $uid = $parameters['uid'];
        $cmd = $parameters['cmd'];
        $accessAllowed = $parameters['hasAccess'];

        if ($accessAllowed && $table === 'sys_file_metadata' && $cmd === 'edit') {
            $fileMetadataRecord = BackendUtility::getRecord('sys_file_metadata', $uid);
            $accessAllowed = $this->checkFileWriteAccessForFileMetaData($fileMetadataRecord);
        }
        return $accessAllowed;
    }

    protected function checkFileWriteAccessForFileMetaData($fileMetadataRecord) {
        $accessAllowed = FALSE;
        if (is_array($fileMetadataRecord) && !empty($fileMetadataRecord['file'])) {
            $file = $fileMetadataRecord['file'];
            // the file relation could be written as sys_file_[uid], strip this off before checking the rights
            if (strpos($file, 'sys_file_') !== FALSE) {
                $file = substr($file, strlen('sys_file_'));
            }
            $fileObject = ResourceFactory::getInstance()->getFileObject((int)$file);
            $accessAllowed = $fileObject->checkActionPermission('write');
        }
        return $accessAllowed;
    }
}