From 18d9fc3af3a8d10a03c8f0b3caadc1bfa77f86dc Mon Sep 17 00:00:00 2001
From: cristy <cristy@aa41f4f7-0bf4-0310-aa73-e5a19afd5a74>
Date: Mon, 15 Dec 2014 02:50:44 +0000
Subject: Detect allocation error earlier

Avoid a segv due to NULL pointer dereference

git-svn-id: https://subversion.imagemagick.org/subversion/ImageMagick/branches/ImageMagick-6@17243 aa41f4f7-0bf4-0310-aa73-e5a19afd5a74
origin:  http://trac.imagemagick.org/changeset/17243

diff --git a/magick/cache.c b/magick/cache.c
index 20afea3..129b769 100644
--- a/magick/cache.c
+++ b/magick/cache.c
@@ -3559,7 +3559,8 @@ static MagickBooleanType OpenPixelCache(Image *image,const MapMode mode,
     packet_size+=sizeof(IndexPacket);
   length=number_pixels*packet_size;
   columns=(size_t) (length/cache_info->rows/packet_size);
-  if (cache_info->columns != columns)
+  if ((cache_info->columns != columns) || ((ssize_t) cache_info->columns < 0) ||
+      ((ssize_t) cache_info->rows < 0))
     ThrowBinaryException(ResourceLimitError,"PixelCacheAllocationFailed",
       image->filename);
   cache_info->length=length;
-- 
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