From: Holger Schemel <info@artsoft.org>
Date: Mon, 7 Jan 2019 15:42:30 +0000 (+0100)
Subject: fixed potential crash bug (accessing invalid memory)
X-Git-Tag: 4.1.2.0~60
X-Git-Url: https://git.artsoft.org/?p=rocksndiamonds.git;a=commitdiff_plain;h=636dfa7f332268725c5377a7bca40f1ad83ad484

fixed potential crash bug (accessing invalid memory)

This change fixes a bug that occured when invoking the changed
function with a "graphic" parameter indicating undefined graphic,
which is defined as "-1" and caused an "array out of bounds" access.

To fix this bug, the function parameter is checked before used.
---

diff --git a/src/tools.c b/src/tools.c
index 459f85a7..33b67795 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -1150,10 +1150,12 @@ void FadeSkipNextFadeOut(void)
 
 static Bitmap *getBitmapFromGraphicOrDefault(int graphic, int default_graphic)
 {
+  if (graphic == IMG_UNDEFINED)
+    return NULL;
+
   boolean redefined = getImageListEntryFromImageID(graphic)->redefined;
 
-  return (graphic == IMG_UNDEFINED ? NULL :
-	  graphic_info[graphic].bitmap != NULL || redefined ?
+  return (graphic_info[graphic].bitmap != NULL || redefined ?
 	  graphic_info[graphic].bitmap :
 	  graphic_info[default_graphic].bitmap);
 }