fix: Ignore preview requests for invalid file ids

Signed-off-by: Julius Härtl <jus@bitgrid.net>

apps/files/lib/Controller/ApiController.php

@@ -93,6 +93,10 @@ class ApiController extends Controller {
 				throw new NotFoundException();
 			}
 
+			if ($file->getId() <= 0) {
+				return new DataResponse(['message' => 'File not found.'], Http::STATUS_NOT_FOUND);
+			}
+
 			/** @var File $file */
 			$preview = $this->previewManager->getPreview($file, $x, $y, true);
 

apps/files/tests/Controller/ApiControllerTest.php

@@ -157,6 +157,7 @@ class ApiControllerTest extends TestCase {
 
 	public function testGetThumbnailInvalidImage() {
 		$file = $this->createMock(File::class);
+		$file->method('getId')->willReturn(123);
 		$this->userFolder->method('get')
 			->with($this->equalTo('unknown.jpg'))
 			->willReturn($file);
@@ -168,8 +169,19 @@ class ApiControllerTest extends TestCase {
 		$this->assertEquals($expected, $this->apiController->getThumbnail(10, 10, 'unknown.jpg'));
 	}
 
+	public function testGetThumbnailInvalidPartFile() {
+		$file = $this->createMock(File::class);
+		$file->method('getId')->willReturn(0);
+		$this->userFolder->method('get')
+			->with($this->equalTo('unknown.jpg'))
+			->willReturn($file);
+		$expected = new DataResponse(['message' => 'File not found.'], Http::STATUS_NOT_FOUND);
+		$this->assertEquals($expected, $this->apiController->getThumbnail(10, 10, 'unknown.jpg'));
+	}
+
 	public function testGetThumbnail() {
 		$file = $this->createMock(File::class);
+		$file->method('getId')->willReturn(123);
 		$this->userFolder->method('get')
 			->with($this->equalTo('known.jpg'))
 			->willReturn($file);

core/Controller/PreviewController.php

@@ -141,6 +141,10 @@ class PreviewController extends Controller {
 			return new DataResponse([], Http::STATUS_FORBIDDEN);
 		}
 
+		if ($node->getId() <= 0) {
+			return new DataResponse([], Http::STATUS_NOT_FOUND);
+		}
+
 		$storage = $node->getStorage();
 		if ($storage->instanceOfStorage(SharedStorage::class)) {
 			/** @var SharedStorage $storage */

tests/Core/Controller/PreviewControllerTest.php

@@ -187,6 +187,7 @@ class PreviewControllerTest extends \Test\TestCase {
 			->willReturn($userFolder);
 
 		$file = $this->createMock(File::class);
+		$file->method('getId')->willReturn(123);
 		$userFolder->method('get')
 			->with($this->equalTo('file'))
 			->willReturn($file);