From d8ccf0cde8b1df3d44b47f560a69c821bcb96921 Mon Sep 17 00:00:00 2001
From: Cristy <urban-warrior@imagemagick.org>
Date: Thu, 24 Sep 2015 09:37:24 -0400
Subject: [PATCH] Prevent null pointer access in magick/constitute.c

Bug: https://github.com/ImageMagick/ImageMagick/pull/34
---
 magick/constitute.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/magick/constitute.c b/magick/constitute.c
index ff339eecc..820f632dd 100644
--- a/magick/constitute.c
+++ b/magick/constitute.c
@@ -1299,7 +1299,14 @@ MagickExport MagickBooleanType WriteImages(const ImageInfo *image_info,
   sans_exception=DestroyExceptionInfo(sans_exception);
   p=images;
   for ( ; GetNextImageInList(p) != (Image *) NULL; p=GetNextImageInList(p))
-    if (p->scene >= GetNextImageInList(p)->scene)
+  {
+    register Image
+      *next;
+
+    next=GetNextImageInList(p);
+    if (next == (Image *) NULL)
+      break;
+    if (p->scene >= next->scene)
       {
         register ssize_t
           i;
@@ -1312,6 +1319,7 @@ MagickExport MagickBooleanType WriteImages(const ImageInfo *image_info,
           p->scene=(size_t) i++;
         break;
       }
+  }
   /*
     Write images.
   */