Fix dispose pattern in PQC types

Author: vcsjones

src/libraries/Common/src/System/Security/Cryptography/MLDsaCng.Windows.cs

@@ -359,8 +359,13 @@ internal static MLDsaCng ImportPkcs8PrivateKey(byte[] source, out int bytesRead)
         /// <inheritdoc/>
         protected override void Dispose(bool disposing)
         {
-            _key.Dispose();
-            _key = null!;
+            if (disposing)
+            {
+                _key.Dispose();
+                _key = null!;
+            }
+
+            base.Dispose(disposing);
         }
 
         private void ExportKey(

src/libraries/Common/src/System/Security/Cryptography/MLDsaImplementation.Windows.cs

@@ -160,8 +160,13 @@ protected override bool TryExportPkcs8PrivateKeyCore(Span<byte> destination, out
 
         protected override void Dispose(bool disposing)
         {
-            _key?.Dispose();
-            _key = null!;
+            if (disposing)
+            {
+                _key?.Dispose();
+                _key = null!;
+            }
+
+            base.Dispose(disposing);
         }
 
         private void ExportKey(string keyBlobType, int expectedKeySize, Span<byte> destination)

src/libraries/Common/src/System/Security/Cryptography/MLKemCng.Windows.cs

@@ -218,9 +218,11 @@ protected override void Dispose(bool disposing)
         {
             if (disposing)
             {
-                _key.Dispose();
+                _key?.Dispose();
                 _key = null!;
             }
+
+            base.Dispose(disposing);
         }
 
         private void ExportKey(KeyBlobMagicNumber kind, Span<byte> destination)

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/MLDsaOpenSsl.OpenSsl.cs

@@ -60,12 +60,12 @@ private static partial MLDsaAlgorithm AlgorithmFromHandle(
         /// <inheritdoc />
         protected override void Dispose(bool disposing)
         {
-            base.Dispose(disposing);
-
             if (disposing)
             {
                 _key.Dispose();
             }
+
+            base.Dispose(disposing);
         }
 
         /// <inheritdoc />

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/MLKemImplementation.OpenSsl.cs

@@ -64,12 +64,12 @@ internal static MLKemImplementation ImportEncapsulationKeyImpl(MLKemAlgorithm al
 
         protected override void Dispose(bool disposing)
         {
-            base.Dispose(disposing);
-
             if (disposing)
             {
                 _key.Dispose();
             }
+
+            base.Dispose(disposing);
         }
 
         internal SafeEvpPKeyHandle DuplicateHandle() =>  _key.DuplicateHandle();

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/MLKemOpenSsl.OpenSsl.cs

@@ -59,12 +59,12 @@ private static partial MLKemAlgorithm AlgorithmFromHandle(
         /// <inheritdoc />
         protected override void Dispose(bool disposing)
         {
-            base.Dispose(disposing);
-
             if (disposing)
             {
                 _key.Dispose();
             }
+
+            base.Dispose(disposing);
         }
 
         /// <inheritdoc />

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/SlhDsaImplementation.OpenSsl.cs

@@ -50,6 +50,8 @@ protected override void Dispose(bool disposing)
                 _key?.Dispose();
                 _key = null!;
             }
+
+            base.Dispose(disposing);
         }
 
         internal static partial SlhDsaImplementation GenerateKeyCore(SlhDsaAlgorithm algorithm)

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/SlhDsaOpenSsl.OpenSsl.cs

@@ -72,12 +72,12 @@ private static partial SlhDsaAlgorithm AlgorithmFromHandle(SafeEvpPKeyHandle pke
         /// <inheritdoc />
         protected override void Dispose(bool disposing)
         {
-            base.Dispose(disposing);
-
             if (disposing)
             {
                 _key.Dispose();
             }
+
+            base.Dispose(disposing);
         }
 
         protected override void SignDataCore(ReadOnlySpan<byte> data, ReadOnlySpan<byte> context, Span<byte> destination) =>