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Patch 0004-Fix-354-Signed-Integer-Overflow-gd_io.c.patch for GD related Bug #73869

Patch version 2017-01-05 10:33 UTC

Return to Bug #73869 | Download this patch
This patch is obsolete

Obsoleted by patches:

Patch Revisions:

Developer: ondrej

From 4d18edb4a3cb150967648925896adcd666797eaf Mon Sep 17 00:00:00 2001
From: "Christoph M. Becker" <cmbecker69@gmx.de>
Date: Sat, 17 Dec 2016 17:06:58 +0100
Subject: [PATCH 4/4] Fix #354: Signed Integer Overflow gd_io.c

GD2 stores the number of horizontal and vertical chunks as words (i.e. 2
byte unsigned). These values are multiplied and assigned to an int when
reading the image, what can cause integer overflows. We have to avoid
that, and also make sure that either chunk count is actually greater
than zero. If illegal chunk counts are detected, we bail out from
reading the image.
---
 ext/gd/libgd/gd_gd2.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/ext/gd/libgd/gd_gd2.c b/ext/gd/libgd/gd_gd2.c
index 4a752d3..f343db2 100644
--- a/ext/gd/libgd/gd_gd2.c
+++ b/ext/gd/libgd/gd_gd2.c
@@ -136,6 +136,10 @@ static int _gd2GetHeader(gdIOCtxPtr in, int *sx, int *sy, int *cs, int *vers, in
 	GD2_DBG(php_gd_error("%d Chunks vertically", *ncy));
 
 	if (gd2_compressed(*fmt)) {
+		if (*ncx <= 0 || *ncy <= 0 || *ncx > INT_MAX / *ncy) {
+			GD2_DBG(printf ("Illegal chunk counts: %d * %d\n", *ncx, *ncy));
+			goto fail1;
+		}
 		nc = (*ncx) * (*ncy);
 		GD2_DBG(php_gd_error("Reading %d chunk index entries", nc));
 		if (overflow2(sizeof(t_chunk_info), nc)) {
-- 
2.1.4

 
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