From ee37e305bda6a5f83569a7b202b73df4d00151f1 Mon Sep 17 00:00:00 2001
From: Savva Mitrofanov <savvamtr@gmail.com>
Date: Fri, 7 Mar 2025 15:47:24 +0300
Subject: [PATCH] NetworkPkg/DxeNetLib: Fix unaligned access in
 NetblockChecksum

Into this routine the caller passes different data structures with
different alignment that is why casting bulk pointer to UINT16 violates
strict aliasing rule.
---
 NetworkPkg/Library/DxeNetLib/NetBuffer.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/NetworkPkg/Library/DxeNetLib/NetBuffer.c b/NetworkPkg/Library/DxeNetLib/NetBuffer.c
index 4721fbd270..ec22708c0e 100644
--- a/NetworkPkg/Library/DxeNetLib/NetBuffer.c
+++ b/NetworkPkg/Library/DxeNetLib/NetBuffer.c
@@ -1618,20 +1618,12 @@ NetblockChecksum (
   )
 {
   register UINT32  Sum;
+  UINT32 BulkPtr;
 
   Sum = 0;
 
-  //
-  // Add left-over byte, if any
-  //
-  if (Len % 2 != 0) {
-    Sum += *(Bulk + Len - 1);
-  }
-
-  while (Len > 1) {
-    Sum  += *(UINT16 *)Bulk;
-    Bulk += 2;
-    Len  -= 2;
+  for (BulkPtr = 0; BulkPtr < Len; BulkPtr++, Bulk++) {
+    Sum += ((*Bulk) << ((BulkPtr & 1U) * 8U));
   }
 
   //