From 49ccd7e62309dea3304a0c7ca200794e727502a2 Mon Sep 17 00:00:00 2001
From: Dirk Lemstra <dirk@lemstra.org>
Date: Wed, 5 Apr 2023 17:21:45 +0200
Subject: [PATCH] Another improvement of calculating the size of the extent.

---
 coders/tiff.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/coders/tiff.c b/coders/tiff.c
index dedddda0a..044e8cc47 100644
--- a/coders/tiff.c
+++ b/coders/tiff.c
@@ -1814,15 +1814,14 @@ static Image *ReadTIFFImage(const ImageInfo *image_info,
         */
         strip_size=TIFFStripSize(tiff);
         stride=(ssize_t) TIFFVStripSize(tiff,1);
-        extent=(size_t) ((samples_per_pixel+extra_samples)*strip_size);
         length=GetQuantumExtent(image,quantum_info,quantum_type);
-        if (length > stride)
-          extent+=length;
+        extent=MagickMax((size_t) strip_size,rows_per_strip*
+          (size_t) MagickMax(stride,length));
         strip_pixels=(unsigned char *) AcquireQuantumMemory(extent,
-          sizeof(uint32));
+          sizeof(*strip_pixels));
         if (strip_pixels == (unsigned char *) NULL)
           ThrowTIFFException(ResourceLimitError,"MemoryAllocationFailed");
-        (void) memset(strip_pixels,0,extent*sizeof(uint32));
+        (void) memset(strip_pixels,0,extent*sizeof(*strip_pixels));
         strip_id=0;
         p=strip_pixels;
         for (i=0; i < (ssize_t) samples_per_pixel; i++)