From 43c44056f6e0335097998a0e8cfdb2829ffd1908 Mon Sep 17 00:00:00 2001
From: Levi Broderick <GrabYourPitchforks@users.noreply.github.com>
Date: Wed, 25 May 2022 15:56:37 -0700
Subject: [PATCH] Allow ToCryptographicException to create serializable
 exceptions (#69765)

---
 .../Cryptography/CryptoThrowHelper.Windows.cs | 43 ++++++++++++++++++-
 1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/src/libraries/Common/src/System/Security/Cryptography/CryptoThrowHelper.Windows.cs b/src/libraries/Common/src/System/Security/Cryptography/CryptoThrowHelper.Windows.cs
index 2fba282d49f..b41fe846066 100644
--- a/src/libraries/Common/src/System/Security/Cryptography/CryptoThrowHelper.Windows.cs
+++ b/src/libraries/Common/src/System/Security/Cryptography/CryptoThrowHelper.Windows.cs
@@ -2,9 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Diagnostics;
 using System.Security.Cryptography;
 
+#if !NETCOREAPP3_1_OR_GREATER
+using System.Diagnostics;
+using System.Runtime.Serialization;
+#endif
+
 namespace Internal.Cryptography
 {
     internal static class CryptoThrowHelper
@@ -13,19 +17,54 @@ public static CryptographicException ToCryptographicException(this int hr)
         {
             string message = Interop.Kernel32.GetMessage(hr);
 
-            if ((hr & 0x80000000) != 0x80000000)
+            // If the incoming value is non-negative, it's a Win32 error instead of an
+            // HRESULT. We'll convert it to an HRESULT now (subsystem = 0x0007 [win32]).
+            if (hr >= 0)
+            {
                 hr = (hr & 0x0000FFFF) | unchecked((int)0x80070000);
+            }
+
+#if NETCOREAPP3_1_OR_GREATER
+            return new CryptographicException(message)
+            {
+                HResult = hr
+            };
+#else
+            // Prior to .NET Core 3.1, the Exception.HResult property was not publicly
+            // settable, and CryptographicException did not have a ctor which allowed
+            // setting both the message and the HRESULT. We use a subclassed helper
+            // type to allow flowing both pieces of data to receivers.
 
             return new WindowsCryptographicException(hr, message);
+#endif
         }
 
+#if !NETCOREAPP3_1_OR_GREATER
+        [Serializable]
         private sealed class WindowsCryptographicException : CryptographicException
         {
+            private WindowsCryptographicException(SerializationInfo info, StreamingContext context)
+            {
+                Debug.Fail("This should never be called; we swap the active type during serialization.");
+                throw new NotImplementedException();
+            }
+
             public WindowsCryptographicException(int hr, string message)
                 : base(message)
             {
                 HResult = hr;
             }
+
+            public override void GetObjectData(SerializationInfo info, StreamingContext context)
+            {
+                // This exception shouldn't be serialized since it's a private implementation
+                // detail potentially copied across multiple different assemblies. We'll
+                // instead ask the serializer to pretend that we're a normal CryptographicException.
+
+                info.SetType(typeof(CryptographicException));
+                base.GetObjectData(info, context);
+            }
         }
+#endif
     }
 }
-- 
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