From 774d031d3e860ccb63acb3defdeb91e8f3fdf515 Mon Sep 17 00:00:00 2001
From: "Vojtech Vitek (V-Teq)" <vvitek@redhat.com>
Date: Tue, 3 Jan 2012 02:36:51 +0100
Subject: [PATCH] Fix integer overflow during the parsing of invalid exif
 header

Based on:
http://svn.php.net/viewvc/?view=revision&revision=319535
http://svn.php.net/viewvc/?view=revision&revision=319534
---
 ext/exif/exif.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/ext/exif/exif.c b/ext/exif/exif.c
index 85fa1b9..ecfb402 100644
--- a/ext/exif/exif.c
+++ b/ext/exif/exif.c
@@ -2856,11 +2856,11 @@ static int exif_process_IFD_TAG(image_info_type *ImageInfo, char *dir_entry, cha
 		offset_val = php_ifd_get32u(dir_entry+8, ImageInfo->motorola_intel);
 		/* If its bigger than 4 bytes, the dir entry contains an offset. */
 		value_ptr = offset_base+offset_val;
-		if (offset_val+byte_count > IFDlength || value_ptr < dir_entry) {
+		if (byte_count > IFDlength || offset_val > IFDlength-byte_count || value_ptr < dir_entry) {
 			/* It is important to check for IMAGE_FILETYPE_TIFF
 			 * JPEG does not use absolute pointers instead its pointers are
 			 * relative to the start of the TIFF header in APP1 section. */
-			if (offset_val+byte_count>ImageInfo->FileSize || (ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_II && ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_MM && ImageInfo->FileType!=IMAGE_FILETYPE_JPEG)) {
+			if (byte_count > ImageInfo->FileSize || offset_val>ImageInfo->FileSize-byte_count || (ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_II && ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_MM && ImageInfo->FileType!=IMAGE_FILETYPE_JPEG)) {
 				if (value_ptr < dir_entry) {
 					/* we can read this if offset_val > 0 */
 					/* some files have their values in other parts of the file */
-- 
1.7.6.2