From: glennrp <glennrp@git.imagemagick.org>
Date: Mon, 21 Feb 2011 12:08:18 +0000 (+0000)
Subject: Check "count" return while reading the JNG signature.
X-Git-Tag: 7.0.1-0~8127
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3b8763efd02f5343a141d40636f6a8dfdc2c7682;p=imagemagick

Check "count" return while reading the JNG signature.
---

diff --git a/coders/png.c b/coders/png.c
index 5ae188c1a..4cdd673fb 100644
--- a/coders/png.c
+++ b/coders/png.c
@@ -3965,9 +3965,8 @@ static Image *ReadJNGImage(const ImageInfo *image_info,ExceptionInfo *exception)
   /* Verify JNG signature.  */
 
   count=(size_t) ReadBlob(image,8,(unsigned char *) magic_number);
-  (void) count;
 
-  if (memcmp(magic_number,"\213JNG\r\n\032\n",8) != 0)
+  if (count < 8 || memcmp(magic_number,"\213JNG\r\n\032\n",8) != 0)
     ThrowReaderException(CorruptImageError,"ImproperImageHeader");
 
   /* Allocate a MngInfo structure.  */