Save dummy gif for non-image responses in image proxy

diff --git a/wcfsetup/install/files/lib/action/ImageProxyAction.class.php b/wcfsetup/install/files/lib/action/ImageProxyAction.class.php
index 959986174a81b3be8b3fad58acb96af0fe6244c0..7fbc7f3f61b595b8f5a56803ee74b30ce95f1f27 100644 (file)
--- a/wcfsetup/install/files/lib/action/ImageProxyAction.class.php
+++ b/wcfsetup/install/files/lib/action/ImageProxyAction.class.php
@@ -58,32 +58,40 @@ class ImageProxyAction extends AbstractAction {
                        if ($files === false) throw new IllegalLinkException();
                        
                        if (empty($files)) {
-                               // download image
                                try {
-                                       $request = new HTTPRequest($url);
-                                       $request->execute();
-                               }
-                               catch (SystemException $e) {
-                                       throw new IllegalLinkException();
-                               }
-                               $image = $request->getReply()['body'];
-                               
-                               // check file type
-                               $imageData = getimagesizefromstring($image);
-                               if (!$imageData) throw new IllegalLinkException();
-                               
-                               switch ($imageData[2]) {
-                                       case IMAGETYPE_PNG:
-                                               $extension = 'png';
-                                       break;
-                                       case IMAGETYPE_GIF:
-                                               $extension = 'gif';
-                                       break;
-                                       case IMAGETYPE_JPEG:
-                                               $extension = 'jpg';
-                                       break;
-                                       default:
+                                       // download image
+                                       try {
+                                               $request = new HTTPRequest($url);
+                                               $request->execute();
+                                       }
+                                       catch (SystemException $e) {
                                                throw new IllegalLinkException();
+                                       }
+                                       $image = $request->getReply()['body'];
+                                       
+                                       // check file type
+                                       $imageData = getimagesizefromstring($image);
+                                       if (!$imageData) throw new \DomainException();
+                                       
+                                       switch ($imageData[2]) {
+                                               case IMAGETYPE_PNG:
+                                                       $extension = 'png';
+                                               break;
+                                               case IMAGETYPE_GIF:
+                                                       $extension = 'gif';
+                                               break;
+                                               case IMAGETYPE_JPEG:
+                                                       $extension = 'jpg';
+                                               break;
+                                               default:
+                                                       throw new \DomainException();
+                                       }
+                               }
+                               catch (\DomainException $e) {
+                                       // save a dummy image in case the server sent us junk, otherwise we might try to download the file over and over and over again.
+                                       // taken from the public domain gif at https://commons.wikimedia.org/wiki/File%3aBlank.gif
+                                       $image = "\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x80\x00\x00\xFF\xFF\xFF\x00\x00\x00\x21\xF9\x04\x00\x00\x00\x00\x00\x2C\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3B";
+                                       $extension = 'gif';
                                }
                                
                                $fileLocation = $dir.'/'.$fileName.'.'.$extension;