From a7786e10d1bab22f34322e6e711b93b377d6155e Mon Sep 17 00:00:00 2001
From: Thomas Bernard <miniupnp@free.fr>
Date: Tue, 10 Nov 2020 01:54:30 +0100
Subject: [PATCH] (CVE-2020-35523) gtTileContig(): check Tile width for
 overflow

fixes #211

(cherry picked from commit c8d613ef497058fe653c467fc84c70a62a4a71b2)
---
 libtiff/tif_getimage.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/libtiff/tif_getimage.c b/libtiff/tif_getimage.c
index c6edd27c..b1f7cc95 100644
--- a/libtiff/tif_getimage.c
+++ b/libtiff/tif_getimage.c
@@ -31,6 +31,7 @@
  */
 #include "tiffiop.h"
 #include <stdio.h>
+#include <limits.h>
 
 static int gtTileContig(TIFFRGBAImage*, uint32*, uint32, uint32);
 static int gtTileSeparate(TIFFRGBAImage*, uint32*, uint32, uint32);
@@ -647,12 +648,20 @@ gtTileContig(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
 
     flip = setorientation(img);
     if (flip & FLIP_VERTICALLY) {
-	    y = h - 1;
-	    toskew = -(int32)(tw + w);
+        if ((tw + w) > INT_MAX) {
+            TIFFErrorExt(tif->tif_clientdata, TIFFFileName(tif), "%s", "unsupported tile size (too wide)");
+            return (0);
+        }
+        y = h - 1;
+        toskew = -(int32)(tw + w);
     }
     else {
-	    y = 0;
-	    toskew = -(int32)(tw - w);
+        if (tw > (INT_MAX + w)) {
+            TIFFErrorExt(tif->tif_clientdata, TIFFFileName(tif), "%s", "unsupported tile size (too wide)");
+            return (0);
+        }
+        y = 0;
+        toskew = -(int32)(tw - w);
     }
      
     /*