Prevented possible XSS via link attachments

This filters out potentially malicious javascript: or data: uri's coming
through to be attached to attachments.
Added tests to cover.

Thanks to Yassine ABOUKIR (@yassineaboukir on twitter) for reporting this
vulnerability.
This commit is contained in:
Dan Brown 2020-10-31 15:01:52 +00:00
parent 18bcafaee4
commit 349162ea13
No known key found for this signature in database
GPG Key ID: 46D9F943C24A2EF9
5 changed files with 80 additions and 31 deletions

View File

@ -110,7 +110,7 @@ class AttachmentController extends Controller
try { try {
$this->validate($request, [ $this->validate($request, [
'attachment_edit_name' => 'required|string|min:1|max:255', 'attachment_edit_name' => 'required|string|min:1|max:255',
'attachment_edit_url' => 'string|min:1|max:255' 'attachment_edit_url' => 'string|min:1|max:255|safe_url'
]); ]);
} catch (ValidationException $exception) { } catch (ValidationException $exception) {
return response()->view('attachments.manager-edit-form', array_merge($request->only(['attachment_edit_name', 'attachment_edit_url']), [ return response()->view('attachments.manager-edit-form', array_merge($request->only(['attachment_edit_name', 'attachment_edit_url']), [
@ -145,7 +145,7 @@ class AttachmentController extends Controller
$this->validate($request, [ $this->validate($request, [
'attachment_link_uploaded_to' => 'required|integer|exists:pages,id', 'attachment_link_uploaded_to' => 'required|integer|exists:pages,id',
'attachment_link_name' => 'required|string|min:1|max:255', 'attachment_link_name' => 'required|string|min:1|max:255',
'attachment_link_url' => 'required|string|min:1|max:255' 'attachment_link_url' => 'required|string|min:1|max:255|safe_url'
]); ]);
} catch (ValidationException $exception) { } catch (ValidationException $exception) {
return response()->view('attachments.manager-link-form', array_merge($request->only(['attachment_link_name', 'attachment_link_url']), [ return response()->view('attachments.manager-link-form', array_merge($request->only(['attachment_link_name', 'attachment_link_url']), [
@ -161,7 +161,7 @@ class AttachmentController extends Controller
$attachmentName = $request->get('attachment_link_name'); $attachmentName = $request->get('attachment_link_name');
$link = $request->get('attachment_link_url'); $link = $request->get('attachment_link_url');
$attachment = $this->attachmentService->saveNewFromLink($attachmentName, $link, $pageId); $attachment = $this->attachmentService->saveNewFromLink($attachmentName, $link, intval($pageId));
return view('attachments.manager-link-form', [ return view('attachments.manager-link-form', [
'pageId' => $pageId, 'pageId' => $pageId,

View File

@ -43,6 +43,13 @@ class AppServiceProvider extends ServiceProvider
return substr_count($uploadName, '.') < 2; return substr_count($uploadName, '.') < 2;
}); });
Validator::extend('safe_url', function ($attribute, $value, $parameters, $validator) {
$cleanLinkName = strtolower(trim($value));
$isJs = strpos($cleanLinkName, 'javascript:') === 0;
$isData = strpos($cleanLinkName, 'data:') === 0;
return !$isJs && !$isData;
});
// Custom blade view directives // Custom blade view directives
Blade::directive('icon', function ($expression) { Blade::directive('icon', function ($expression) {
return "<?php echo icon($expression); ?>"; return "<?php echo icon($expression); ?>";

View File

@ -88,12 +88,8 @@ class AttachmentService extends UploadService
/** /**
* Save a new File attachment from a given link and name. * Save a new File attachment from a given link and name.
* @param string $name
* @param string $link
* @param int $page_id
* @return Attachment
*/ */
public function saveNewFromLink($name, $link, $page_id) public function saveNewFromLink(string $name, string $link, int $page_id): Attachment
{ {
$largestExistingOrder = Attachment::where('uploaded_to', '=', $page_id)->max('order'); $largestExistingOrder = Attachment::where('uploaded_to', '=', $page_id)->max('order');
return Attachment::forceCreate([ return Attachment::forceCreate([
@ -123,13 +119,11 @@ class AttachmentService extends UploadService
/** /**
* Update the details of a file. * Update the details of a file.
* @param Attachment $attachment
* @param $requestData
* @return Attachment
*/ */
public function updateFile(Attachment $attachment, $requestData) public function updateFile(Attachment $attachment, array $requestData): Attachment
{ {
$attachment->name = $requestData['name']; $attachment->name = $requestData['name'];
if (isset($requestData['link']) && trim($requestData['link']) !== '') { if (isset($requestData['link']) && trim($requestData['link']) !== '') {
$attachment->path = $requestData['link']; $attachment->path = $requestData['link'];
if (!$attachment->external) { if (!$attachment->external) {
@ -137,6 +131,7 @@ class AttachmentService extends UploadService
$attachment->external = true; $attachment->external = true;
} }
} }
$attachment->save(); $attachment->save();
return $attachment; return $attachment;
} }

View File

@ -90,6 +90,7 @@ return [
'required_without' => 'The :attribute field is required when :values is not present.', 'required_without' => 'The :attribute field is required when :values is not present.',
'required_without_all' => 'The :attribute field is required when none of :values are present.', 'required_without_all' => 'The :attribute field is required when none of :values are present.',
'same' => 'The :attribute and :other must match.', 'same' => 'The :attribute and :other must match.',
'safe_url' => 'The provided link may not be safe.',
'size' => [ 'size' => [
'numeric' => 'The :attribute must be :size.', 'numeric' => 'The :attribute must be :size.',
'file' => 'The :attribute must be :size kilobytes.', 'file' => 'The :attribute must be :size kilobytes.',

View File

@ -3,39 +3,51 @@
use BookStack\Uploads\Attachment; use BookStack\Uploads\Attachment;
use BookStack\Entities\Page; use BookStack\Entities\Page;
use BookStack\Auth\Permissions\PermissionService; use BookStack\Auth\Permissions\PermissionService;
use BookStack\Uploads\AttachmentService;
use Illuminate\Http\UploadedFile;
use Tests\TestCase; use Tests\TestCase;
use Tests\TestResponse;
class AttachmentTest extends TestCase class AttachmentTest extends TestCase
{ {
/** /**
* Get a test file that can be uploaded * Get a test file that can be uploaded
* @param $fileName
* @return \Illuminate\Http\UploadedFile
*/ */
protected function getTestFile($fileName) protected function getTestFile(string $fileName): UploadedFile
{ {
return new \Illuminate\Http\UploadedFile(base_path('tests/test-data/test-file.txt'), $fileName, 'text/plain', 55, null, true); return new UploadedFile(base_path('tests/test-data/test-file.txt'), $fileName, 'text/plain', 55, null, true);
} }
/** /**
* Uploads a file with the given name. * Uploads a file with the given name.
* @param $name
* @param int $uploadedTo
* @return \Illuminate\Foundation\Testing\TestResponse
*/ */
protected function uploadFile($name, $uploadedTo = 0) protected function uploadFile(string $name, int $uploadedTo = 0): \Illuminate\Foundation\Testing\TestResponse
{ {
$file = $this->getTestFile($name); $file = $this->getTestFile($name);
return $this->call('POST', '/attachments/upload', ['uploaded_to' => $uploadedTo], [], ['file' => $file], []); return $this->call('POST', '/attachments/upload', ['uploaded_to' => $uploadedTo], [], ['file' => $file], []);
} }
/**
* Create a new attachment
*/
protected function createAttachment(Page $page): Attachment
{
$this->post('attachments/link', [
'attachment_link_url' => 'https://example.com',
'attachment_link_name' => 'Example Attachment Link',
'attachment_link_uploaded_to' => $page->id,
]);
return Attachment::query()->latest()->first();
}
/** /**
* Delete all uploaded files. * Delete all uploaded files.
* To assist with cleanup. * To assist with cleanup.
*/ */
protected function deleteUploads() protected function deleteUploads()
{ {
$fileService = $this->app->make(\BookStack\Uploads\AttachmentService::class); $fileService = $this->app->make(AttachmentService::class);
foreach (Attachment::all() as $file) { foreach (Attachment::all() as $file) {
$fileService->deleteFile($file); $fileService->deleteFile($file);
} }
@ -145,21 +157,14 @@ class AttachmentTest extends TestCase
$page = Page::first(); $page = Page::first();
$this->asAdmin(); $this->asAdmin();
$this->call('POST', 'attachments/link', [ $attachment = $this->createAttachment($page);
'attachment_link_url' => 'https://example.com', $update = $this->call('PUT', 'attachments/' . $attachment->id, [
'attachment_link_name' => 'Example Attachment Link',
'attachment_link_uploaded_to' => $page->id,
]);
$attachmentId = Attachment::first()->id;
$update = $this->call('PUT', 'attachments/' . $attachmentId, [
'attachment_edit_name' => 'My new attachment name', 'attachment_edit_name' => 'My new attachment name',
'attachment_edit_url' => 'https://test.example.com' 'attachment_edit_url' => 'https://test.example.com'
]); ]);
$expectedData = [ $expectedData = [
'id' => $attachmentId, 'id' => $attachment->id,
'path' => 'https://test.example.com', 'path' => 'https://test.example.com',
'name' => 'My new attachment name', 'name' => 'My new attachment name',
'uploaded_to' => $page->id 'uploaded_to' => $page->id
@ -242,4 +247,45 @@ class AttachmentTest extends TestCase
$this->deleteUploads(); $this->deleteUploads();
} }
public function test_data_and_js_links_cannot_be_attached_to_a_page()
{
$page = Page::first();
$this->asAdmin();
$badLinks = [
'javascript:alert("bunny")',
' javascript:alert("bunny")',
'JavaScript:alert("bunny")',
"\t\n\t\nJavaScript:alert(\"bunny\")",
"data:text/html;<a></a>",
"Data:text/html;<a></a>",
"Data:text/html;<a></a>",
];
foreach ($badLinks as $badLink) {
$linkReq = $this->post('attachments/link', [
'attachment_link_url' => $badLink,
'attachment_link_name' => 'Example Attachment Link',
'attachment_link_uploaded_to' => $page->id,
]);
$linkReq->assertStatus(422);
$this->assertDatabaseMissing('attachments', [
'path' => $badLink,
]);
}
$attachment = $this->createAttachment($page);
foreach ($badLinks as $badLink) {
$linkReq = $this->put('attachments/' . $attachment->id, [
'attachment_edit_url' => $badLink,
'attachment_edit_name' => 'Example Attachment Link',
]);
$linkReq->assertStatus(422);
$this->assertDatabaseMissing('attachments', [
'path' => $badLink,
]);
}
}
} }