From 47f2fb61a3a64667bce1a8398a8fcb1b348ff122 Mon Sep 17 00:00:00 2001
From: erouault <erouault>
Date: Wed, 11 Jan 2017 12:15:01 +0000
Subject: [PATCH] * libtiff/tif_jpeg.c: avoid integer division by zero in
 JPEGSetupEncode() when horizontal or vertical sampling is set to 0. Fixes
 http://bugzilla.maptools.org/show_bug.cgi?id=2653

---
 ChangeLog          | 6 ++++++
 libtiff/tif_jpeg.c | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index c82bc76..a7208f5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2017-01-11 Even Rouault <even.rouault at spatialys.com>
 
+	* libtiff/tif_jpeg.c: avoid integer division by zero in
+	JPEGSetupEncode() when horizontal or vertical sampling is set to 0.
+	Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2653
+
+2017-01-11 Even Rouault <even.rouault at spatialys.com>
+
 	* tools/tiffcp.c: error out cleanly in cpContig2SeparateByRow and
 	cpSeparate2ContigByRow if BitsPerSample != 8 to avoid heap based overflow.
 	Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2656 and
diff --git a/libtiff/tif_jpeg.c b/libtiff/tif_jpeg.c
index 38595f9..6c17c38 100644
--- a/libtiff/tif_jpeg.c
+++ b/libtiff/tif_jpeg.c
@@ -1626,6 +1626,13 @@ JPEGSetupEncode(TIFF* tif)
 	case PHOTOMETRIC_YCBCR:
 		sp->h_sampling = td->td_ycbcrsubsampling[0];
 		sp->v_sampling = td->td_ycbcrsubsampling[1];
+                if( sp->h_sampling == 0 || sp->v_sampling == 0 )
+                {
+                    TIFFErrorExt(tif->tif_clientdata, module,
+                            "Invalig horizontal/vertical sampling value");
+                    return (0);
+                }
+
 		/*
 		 * A ReferenceBlackWhite field *must* be present since the
 		 * default value is inappropriate for YCbCr.  Fill in the