From b7426cc131d837de8d139b8007f66f9db59c4f6a Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Sat, 5 Feb 2022 20:36:41 +0100
Subject: [PATCH] (CVE-2022-0562) TIFFReadDirectory(): avoid calling memcpy()
 with a null source pointer and size of zero (fixes #362)

(cherry picked from commit 561599c99f987dc32ae110370cfdd7df7975586b)
---
 libtiff/tif_dirread.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libtiff/tif_dirread.c b/libtiff/tif_dirread.c
index 1e6f1c2f..d68aecc5 100644
--- a/libtiff/tif_dirread.c
+++ b/libtiff/tif_dirread.c
@@ -4083,7 +4083,8 @@ TIFFReadDirectory(TIFF* tif)
                     goto bad;
                 }
 
-                memcpy(new_sampleinfo, tif->tif_dir.td_sampleinfo, old_extrasamples * sizeof(uint16));
+                if (old_extrasamples > 0)
+                    memcpy(new_sampleinfo, tif->tif_dir.td_sampleinfo, old_extrasamples * sizeof(uint16));
                 _TIFFsetShortArray(&tif->tif_dir.td_sampleinfo, new_sampleinfo, tif->tif_dir.td_extrasamples);
                 _TIFFfree(new_sampleinfo);
         }