8185292: Stricter key generation

Reviewed-by: mullan

src/java.base/share/classes/com/sun/crypto/provider/DHKeyAgreement.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2017, 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
@@ -28,11 +28,13 @@ package com.sun.crypto.provider;
 import java.util.*;
 import java.lang.*;
 import java.math.BigInteger;
+import java.security.AccessController;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.Key;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.security.PrivilegedAction;
 import java.security.ProviderException;
 import java.security.spec.AlgorithmParameterSpec;
 import java.security.spec.InvalidKeySpecException;
@@ -60,6 +62,17 @@ extends KeyAgreementSpi {
     private BigInteger x = BigInteger.ZERO; // the private value
     private BigInteger y = BigInteger.ZERO;
 
+    private static class AllowKDF {
+
+        private static final boolean VALUE = getValue();
+
+        private static boolean getValue() {
+            return AccessController.doPrivileged(
+                (PrivilegedAction<Boolean>)
+                () -> Boolean.getBoolean("jdk.crypto.KeyAgreement.legacyKDF"));
+        }
+    }
+
     /**
      * Empty constructor
      */
@@ -367,6 +380,14 @@ extends KeyAgreementSpi {
         if (algorithm == null) {
             throw new NoSuchAlgorithmException("null algorithm");
         }
+
+        if (!algorithm.equalsIgnoreCase("TlsPremasterSecret") &&
+            !AllowKDF.VALUE) {
+
+            throw new NoSuchAlgorithmException("Unsupported secret key "
+                                               + "algorithm: " + algorithm);
+        }
+
         byte[] secret = engineGenerateSecret();
         if (algorithm.equalsIgnoreCase("DES")) {
             // DES