File GraphicsMagick-CVE-2017-9142.patch of Package GraphicsMagick.7782

Index: GraphicsMagick-1.3.25/coders/png.c
===================================================================
--- GraphicsMagick-1.3.25.orig/coders/png.c	2017-05-30 13:41:36.615260067 +0200
+++ GraphicsMagick-1.3.25/coders/png.c	2017-05-30 14:15:04.954314787 +0200
@@ -3123,10 +3123,11 @@ static Image *ReadOneJNGImage(MngInfo *m
             (void) LogMagickEvent(CoderEvent,GetMagickModule(),
                                   "    Copying JDAT chunk data"
                                   " to color_blob.");
-          if (color_image != (Image *)NULL)
-            (void) WriteBlob(color_image,length,(char *) chunk);
-          if (length)
+          if (length) {
+            if (color_image != (Image *)NULL)
+              (void) WriteBlob(color_image,length,(char *) chunk);
             MagickFreeMemory(chunk);
+          }
           continue;
         }