From c2ba65e972d3ff25f1a2947cb222cee1fccdca6a Mon Sep 17 00:00:00 2001
From: Leonard Hecker <lhecker@microsoft.com>
Date: Tue, 9 Jul 2024 15:47:38 +0200
Subject: [PATCH] AtlasEngine: Fix a buffer overrun

---
 src/renderer/atlas/BackendD3D.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/renderer/atlas/BackendD3D.cpp b/src/renderer/atlas/BackendD3D.cpp
index a9e81422d0a..33cb3147355 100644
--- a/src/renderer/atlas/BackendD3D.cpp
+++ b/src/renderer/atlas/BackendD3D.cpp
@@ -1069,12 +1069,13 @@ void BackendD3D::_uploadBackgroundBitmap(const RenderingPayload& p)
 
     auto src = std::bit_cast<const char*>(p.backgroundBitmap.data());
     const auto srcEnd = std::bit_cast<const char*>(p.backgroundBitmap.data() + p.backgroundBitmap.size());
+    const auto srcWidth = p.s->viewportCellCount.x * sizeof(u32);
     const auto srcStride = p.colorBitmapRowStride * sizeof(u32);
     auto dst = static_cast<char*>(mapped.pData);
 
     while (src < srcEnd)
     {
-        memcpy(dst, src, srcStride);
+        memcpy(dst, src, srcWidth);
         src += srcStride;
         dst += mapped.RowPitch;
     }