Fix: Improve sanitization of folder and file names

lib/Service/GoogleDriveAPIService.php

@@ -17,6 +17,7 @@
 use OC\User\NoUserException;
 use OCA\Google\AppInfo\Application;
 use OCA\Google\BackgroundJob\ImportDriveJob;
+use OCA\Google\Service\Utils\FileUtils;
 use OCP\BackgroundJob\IJobList;
 use OCP\Files\File;
 use OCP\Files\Folder;
@@ -51,6 +52,7 @@ public function __construct(
 		private IJobList $jobList,
 		private UserScopeService $userScopeService,
 		private GoogleAPIService $googleApiService,
+		private FileUtils $fileUtils,
 	) {
 	}
 
@@ -540,7 +542,7 @@ private function createDirsUnder(array &$directoriesById, Folder $currentFolder,
 			// create dir if we are on top OR if its parent is current dir
 			if (($currentFolderId === '' && !array_key_exists($parentId, $directoriesById))
 				|| $parentId === $currentFolderId) {
-				$name = $dir['name'];
+				$name = $this->fileUtils->sanitizeFilename((string)($dir['name']), (string)$id);
 				if (!$currentFolder->nodeExists($name)) {
 					$newDir = $currentFolder->newFolder($name);
 				} else {
@@ -550,7 +552,7 @@ private function createDirsUnder(array &$directoriesById, Folder $currentFolder,
 					}
 				}
 				$directoriesById[$id]['node'] = $newDir;
-				$success = $this->createDirsUnder($directoriesById, $newDir, $id);
+				$success = $this->createDirsUnder($directoriesById, $newDir, (string)$id);
 				if (!$success) {
 					return false;
 				}
@@ -623,7 +625,7 @@ private function downloadAndSaveFile(
 	 * @return string name of the file to be saved
 	 */
 	private function getFileName(array $fileItem, string $userId, bool $hasNameConflict): string {
-		$fileName = preg_replace('/\/|\n|[^._A-Za-z0-9-]/', '-', $fileItem['name'] ?? 'Untitled');
+		$fileName = $this->fileUtils->sanitizeFilename((string)($fileItem['name']), (string)$fileItem['id']);
 
 		if (in_array($fileItem['mimeType'], array_values(self::DOCUMENT_MIME_TYPES))) {
 			$documentFormat = $this->getUserDocumentFormat($userId);

lib/Service/GooglePhotosAPIService.php

@@ -16,6 +16,7 @@
 use Exception;
 use OCA\Google\AppInfo\Application;
 use OCA\Google\BackgroundJob\ImportPhotosJob;
+use OCA\Google\Service\Utils\FileUtils;
 use OCP\BackgroundJob\IJobList;
 use OCP\Files\FileInfo;
 use OCP\Files\Folder;
@@ -40,6 +41,7 @@ public function __construct(
 		private IJobList $jobList,
 		private UserScopeService $userScopeService,
 		private GoogleAPIService $googleApiService,
+		private FileUtils $fileUtils,
 	) {
 	}
 
@@ -277,7 +279,7 @@ public function importPhotos(
 		$seenIds = [];
 		foreach ($albums as $album) {
 			$albumId = $album['id'];
-			$albumName = preg_replace('/\//', '_', $album['title'] ?? 'Untitled');
+			$albumName = $this->fileUtils->sanitizeFilename((string)($album['title']), (string)$album['id']);
 			if (!$folder->nodeExists($albumName)) {
 				$albumFolder = $folder->newFolder($albumName);
 			} else {
@@ -372,7 +374,7 @@ public function importPhotos(
 	 * @throws \OCP\Files\NotPermittedException
 	 */
 	private function getPhoto(string $userId, array $photo, Folder $albumFolder): ?int {
-		$photoName = preg_replace('/\//', '_', $photo['filename'] ?? 'Untitled');
+		$photoName = $this->fileUtils->sanitizeFilename($photo['filename'], (string)$photo['id']);
 		if ($albumFolder->nodeExists($photoName)) {
 			$photoName = $photo['id'] . '_' . $photoName;
 		}

lib/Service/Utils/FileUtils.php

@@ -0,0 +1,135 @@
+<?php
+
+namespace OCA\Google\Service\Utils;
+
+use OCP\Files\EmptyFileNameException;
+use OCP\Files\FileNameTooLongException;
+use OCP\Files\InvalidCharacterInPathException;
+use OCP\Files\InvalidDirectoryException;
+use OCP\Files\ReservedWordException;
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\NotFoundExceptionInterface;
+use Psr\Log\LoggerInterface;
+
+final class FileUtils {
+
+	public function __construct(
+		private \OCP\Files\IFilenameValidator $validator,
+		private \OCP\IConfig $config,
+		private LoggerInterface $logger,
+	) {
+	}
+
+	/**
+	 * Sanitize the filename to ensure it is valid, does not exceed length limits.
+	 *
+	 * @param string $filename The original filename to sanitize.
+	 * @param string $id A unique ID to append if necessary to ensure uniqueness.
+	 * @param int $recursionDepth The current recursion depth (used to prevent infinite loops).
+	 * @param string|null $originalFilename The original filename for logging.
+	 * @return string The sanitized and validated filename.
+	 */
+	public function sanitizeFilename(
+		string $filename,
+		string $id,
+		int $recursionDepth = 0,
+		?string $originalFilename = null,
+	): string {
+		if ($recursionDepth > 15) {
+			$filename = 'Untitled_' . $id;
+			$this->logger->warning('Maximum recursion depth reached while sanitizing filename: ' . ($originalFilename ?? $filename) . ' renaming to ' . $filename);
+			return $filename;
+		}
+
+		if ($originalFilename === null) {
+			$originalFilename = $filename;
+		}
+
+		// Use Nextcloud 32+ validator if available
+		if (version_compare($this->config->getSystemValueString('version', '0.0.0'), '32.0.0', '>=')) {
+			$this->logger->debug('Using Nextcloud 32+ filename validator for sanitization.');
+			try {
+				return $this->validator->sanitizeFilename($filename);
+			} catch (\InvalidArgumentException|NotFoundExceptionInterface|ContainerExceptionInterface $exception) {
+				$this->logger->error('Unable to sanitize filename: ' . $filename, ['exception' => $exception]);
+				return 'Untitled_' . $id;
+			}
+		} else {
+			$this->logger->debug('Using legacy filename sanitization method.');
+		}
+
+		// Trim whitespace and trailing dots
+		$filename = rtrim(trim($filename), '.');
+
+		// Append ID if needed
+		if ($originalFilename !== $filename && strpos($filename, $id) === false) {
+			$filename = self::appendIdBeforeExtension($filename, $id);
+		}
+
+		// Enforce max length
+		$maxLength = 254;
+		if (mb_strlen($filename) > $maxLength) {
+			$filename = self::truncateAndAppendId($filename, $id, $maxLength);
+		}
+
+		try {
+			$this->validator->validateFilename($filename);
+			if ($recursionDepth > 0) {
+				$this->logger->info('Filename sanitized successfully: "' . $filename . '" (original: "' . $originalFilename . '")');
+			}
+			return $filename;
+		} catch (\Throwable $exception) {
+			$this->logger->warning('Exception during filename validation: ' . $filename, ['exception' => $exception]);
+			$filename = self::handleFilenameException($filename, $id, $exception, $this->logger);
+			if (strpos($filename, $id) === false) {
+				$filename = self::appendIdBeforeExtension($filename, $id);
+			}
+			return $this->sanitizeFilename($filename, $id, $recursionDepth + 1, $originalFilename);
+		}
+	}
+
+	private static function appendIdBeforeExtension(string $filename, string $id): string {
+		$pathInfo = pathinfo($filename);
+		if (isset($pathInfo['extension'])) {
+			return $pathInfo['filename'] . '_' . $id . '.' . $pathInfo['extension'];
+		}
+		return $filename . '_' . $id;
+	}
+
+	private static function truncateAndAppendId(string $filename, string $id, int $maxLength): string {
+		$pathInfo = pathinfo($filename);
+		$baseLength = $maxLength - mb_strlen($id) - 2;
+		if (isset($pathInfo['extension'])) {
+			$baseLength -= mb_strlen($pathInfo['extension']);
+			return mb_substr($pathInfo['filename'], 0, $baseLength) . '_' . $id . '.' . $pathInfo['extension'];
+		}
+		return mb_substr($filename, 0, $baseLength) . '_' . $id;
+	}
+
+	private static function handleFilenameException(string $filename, string $id, \Throwable $exception, LoggerInterface $logger): string {
+		if ($exception instanceof FileNameTooLongException) {
+			return mb_substr($filename, 0, 254 - mb_strlen($id) - 2);
+		}
+		if ($exception instanceof EmptyFileNameException) {
+			return 'Untitled';
+		}
+		if ($exception instanceof InvalidCharacterInPathException) {
+			if (preg_match('/"(.*?)"/', $exception->getMessage(), $matches)) {
+				$invalidChars = array_merge(str_split($matches[1]), ['"']);
+				return str_replace($invalidChars, '-', $filename);
+			}
+		}
+		if ($exception instanceof InvalidDirectoryException) {
+			$logger->error('Invalid directory detected in filename: ' . $exception->getMessage());
+			return 'Untitled';
+		}
+		if ($exception instanceof ReservedWordException) {
+			if (preg_match('/"(.*?)"/', $exception->getMessage(), $matches)) {
+				$reservedWord = $matches[1];
+				return str_ireplace($reservedWord, '-' . $reservedWord . '-', $filename);
+			}
+		}
+		$logger->error('Unknown exception encountered during filename sanitization: ' . $filename);
+		return 'Untitled';
+	}
+}