8308808: SunMSCAPI public keys returns internal key array

src/jdk.crypto.mscapi/windows/classes/sun/security/mscapi/CPublicKey.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -87,13 +87,13 @@ public byte[] getEncoded() {
             if (encoding == null) {
                 try {
                     encoding = KeyFactory.getInstance("EC").generatePublic(
-                                new ECPublicKeySpec(getW(), getParams()))
-                            .getEncoded();
+                            new ECPublicKeySpec(getW(), getParams()))
+                        .getEncoded();
                 } catch (Exception e) {
                     // ignore
                 }
             }
-            return encoding;
+            return (encoding == null) ? null : encoding.clone();
         }
 
         @Override
@@ -179,7 +179,7 @@ public byte[] getEncoded() {
                     // ignore
                 }
             }
-            return encoding;
+            return (encoding == null) ? null : encoding.clone();
         }
 
         private native byte[] getExponent(byte[] keyBlob) throws KeyException;

test/jdk/sun/security/mscapi/EncodingMutability.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.security.KeyPairGenerator;
+import java.security.PublicKey;
+
+/*
+ * @test
+ * @bug 8308808
+ * @requires os.family == "windows"
+ * @modules jdk.crypto.mscapi
+ * @run main EncodingMutability
+ */
+public class EncodingMutability {
+
+    public static void main(String[] args) throws Exception {
+        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA", "SunMSCAPI");
+        PublicKey publicKey = keyGen.generateKeyPair().getPublic();
+        byte initialByte = publicKey.getEncoded()[0];
+        publicKey.getEncoded()[0] = 0;
+        byte mutatedByte = publicKey.getEncoded()[0];
+
+        if (initialByte != mutatedByte) {
+            System.out.println("Was able to mutate first byte of pubkey from " + initialByte + " to " + mutatedByte);
+            throw new RuntimeException("Pubkey was mutated via getEncoded");
+        }
+    }
+}