Avoid DOS with gigant ckSize values (#60)

Normalize quotes and avoid DOS with gigant ckSize values

garbage.php

@@ -4,21 +4,24 @@
 @ini_set('output_buffering', 'Off');
 @ini_set('output_handler', '');
 // Headers
-header( "HTTP/1.1 200 OK" );
+header('HTTP/1.1 200 OK');
 // Download follows...
 header('Content-Description: File Transfer');
 header('Content-Type: application/octet-stream');
 header('Content-Disposition: attachment; filename=random.dat'); 
 header('Content-Transfer-Encoding: binary');
 // Never cache me
-header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
-header("Cache-Control: post-check=0, pre-check=0", false);
-header("Pragma: no-cache");
+header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0');
+header('Cache-Control: post-check=0, pre-check=0', false);
+header('Pragma: no-cache');
 // Generate data
 $data=openssl_random_pseudo_bytes(1048576);
 // Deliver chunks of 1048576 bytes
-for($i=0;$i<intval($_GET["ckSize"]);$i++){
+$chunks=isset($_GET['ckSize']) ?? intval($_GET['ckSize']) : 4;
+if(empty($chunks)){$chunks = 4;}
+if($chunks>100){$chunks = 100;}
+for($i=0;$i<$chunks;$i++){
     echo $data;
     flush();
 }
-?>
+?>