From 8ad1d7d665c9867621193d4f8362cdb983602cae Mon Sep 17 00:00:00 2001
From: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Date: Fri, 19 Mar 2021 11:46:08 +0100
Subject: [PATCH] Big-endian fix: PEBuilder.CalculateChecksum (#49816)

* Always use little-endian encoding to compute checksum
---
 .../src/System/Reflection/PortableExecutable/PEBuilder.cs              | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libraries/System.Reflection.Metadata/src/System/Reflection/PortableExecutable/PEBuilder.cs b/src/libraries/System.Reflection.Metadata/src/System/Reflection/PortableExecutable/PEBuilder.cs
index 112359f..a2de3a1 100644
--- a/src/libraries/System.Reflection.Metadata/src/System/Reflection/PortableExecutable/PEBuilder.cs
+++ b/src/libraries/System.Reflection.Metadata/src/System/Reflection/PortableExecutable/PEBuilder.cs
@@ -549,7 +549,8 @@ namespace System.Reflection.PortableExecutable
 
                     while (ptr < end)
                     {
-                        checksum = AggregateChecksum(checksum, *(ushort*)ptr);
+                        // little-endian encoding:
+                        checksum = AggregateChecksum(checksum, (ushort)(ptr[1] << 8 | ptr[0]));
                         ptr += sizeof(ushort);
                     }
                 }
-- 
2.7.4