From a8e550f5bfd809cb2ec4c58621a25b2902f46ce1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hajo=20Nils=20Krabbenho=CC=88ft?=
 <fxtentacle@googlemail.com>
Date: Wed, 16 Sep 2015 22:04:42 +0200
Subject: [PATCH] Fixed crash when reading b/w tif images (fixes #5579)

---
 modules/imgcodecs/src/grfmt_tiff.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/modules/imgcodecs/src/grfmt_tiff.cpp b/modules/imgcodecs/src/grfmt_tiff.cpp
index fc6f2368ad..a805274244 100644
--- a/modules/imgcodecs/src/grfmt_tiff.cpp
+++ b/modules/imgcodecs/src/grfmt_tiff.cpp
@@ -247,7 +247,12 @@ bool  TiffDecoder::readData( Mat& img )
                (!is_tiled && tile_height0 == std::numeric_limits<uint32>::max()) )
                 tile_height0 = m_height;
 
-            const size_t buffer_size = bpp * ncn * tile_height0 * tile_width0;
+            if(dst_bpp == 8) {
+                // we will use TIFFReadRGBA* functions, so allocate temporary buffer for 32bit RGBA
+                bpp = 8;
+                ncn = 4;
+            }
+            const size_t buffer_size = (bpp/bitsPerByte) * ncn * tile_height0 * tile_width0;
             AutoBuffer<uchar> _buffer( buffer_size );
             uchar* buffer = _buffer;
             ushort* buffer16 = (ushort*)buffer;