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	/*
	* Copyright (c) 2018, 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. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* 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.
	*/

	package sun.security.ssl;

	import java.io.IOException;
	import java.security.GeneralSecurityException;
	import java.security.InvalidAlgorithmParameterException;
	import java.security.InvalidKeyException;
	import java.security.KeyPair;
	import java.security.NoSuchAlgorithmException;
	import java.security.PrivateKey;
	import java.security.PublicKey;
	import java.security.SecureRandom;
	import java.security.interfaces.RSAPublicKey;
	import java.security.spec.AlgorithmParameterSpec;
	import javax.crypto.BadPaddingException;
	import javax.crypto.Cipher;
	import javax.crypto.KeyGenerator;
	import javax.crypto.SecretKey;
	import javax.net.ssl.SSLHandshakeException;
	import sun.security.internal.spec.TlsRsaPremasterSecretParameterSpec;
	import sun.security.util.KeyUtil;

	final class RSAKeyExchange {
	static final SSLPossessionGenerator poGenerator =
	new EphemeralRSAPossessionGenerator();
	static final SSLKeyAgreementGenerator kaGenerator =
	new RSAKAGenerator();

	static final class EphemeralRSAPossession implements SSLPossession {
	// Proof of possession of the private key corresponding to the public
	// key for which a certificate is being provided for authentication.
	final RSAPublicKey popPublicKey;
	final PrivateKey popPrivateKey;

	EphemeralRSAPossession(PrivateKey popPrivateKey,
	RSAPublicKey popPublicKey) {
	this.popPublicKey = popPublicKey;
	this.popPrivateKey = popPrivateKey;
	}
	}

	static final class EphemeralRSACredentials implements SSLCredentials {
	final RSAPublicKey popPublicKey;

	EphemeralRSACredentials(RSAPublicKey popPublicKey) {
	this.popPublicKey = popPublicKey;
	}
	}

	private static final class EphemeralRSAPossessionGenerator
	implements SSLPossessionGenerator {
	// Prevent instantiation of this class.
	private EphemeralRSAPossessionGenerator() {
	// blank
	}

	@Override
	public SSLPossession createPossession(HandshakeContext context) {
	try {
	EphemeralKeyManager ekm =
	context.sslContext.getEphemeralKeyManager();
	KeyPair kp = ekm.getRSAKeyPair(
	true, context.sslContext.getSecureRandom());
	if (kp != null) {
	return new EphemeralRSAPossession(
	kp.getPrivate(), (RSAPublicKey)kp.getPublic());
	} else {
	// Could not generate the ephemeral key, ignore.
	return null;
	}
	} catch (RuntimeException rte) {
	// Could not determine keylength, ignore.
	return null;
	}
	}
	}

	static final
	class RSAPremasterSecret implements SSLPossession, SSLCredentials {
	final SecretKey premasterSecret;

	RSAPremasterSecret(SecretKey premasterSecret) {
	this.premasterSecret = premasterSecret;
	}

	byte[] getEncoded(PublicKey publicKey,
	SecureRandom secureRandom) throws GeneralSecurityException {
	Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);
	cipher.init(Cipher.WRAP_MODE, publicKey, secureRandom);
	return cipher.wrap(premasterSecret);
	}

	@SuppressWarnings("deprecation")
	static RSAPremasterSecret createPremasterSecret(
	ClientHandshakeContext chc) throws GeneralSecurityException {
	String algorithm = chc.negotiatedProtocol.useTLS12PlusSpec() ?
	"SunTls12RsaPremasterSecret" : "SunTlsRsaPremasterSecret";
	KeyGenerator kg = JsseJce.getKeyGenerator(algorithm);
	TlsRsaPremasterSecretParameterSpec spec =
	new TlsRsaPremasterSecretParameterSpec(
	chc.clientHelloVersion,
	chc.negotiatedProtocol.id);
	kg.init(spec, chc.sslContext.getSecureRandom());

	return new RSAPremasterSecret(kg.generateKey());
	}

	@SuppressWarnings("deprecation")
	static RSAPremasterSecret decode(ServerHandshakeContext shc,
	PrivateKey privateKey,
	byte[] encrypted) throws GeneralSecurityException {

	byte[] encoded = null;
	boolean needFailover = false;
	Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);
	try {
	// Try UNWRAP_MODE mode firstly.
	cipher.init(Cipher.UNWRAP_MODE, privateKey,
	new TlsRsaPremasterSecretParameterSpec(
	shc.clientHelloVersion,
	shc.negotiatedProtocol.id),
	shc.sslContext.getSecureRandom());

	// The provider selection can be delayed, please don't call
	// any Cipher method before the call to Cipher.init().
	needFailover = !KeyUtil.isOracleJCEProvider(
	cipher.getProvider().getName());
	} catch (InvalidKeyException \| UnsupportedOperationException iue) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning("The Cipher provider "
	+ safeProviderName(cipher)
	+ " caused exception: " + iue.getMessage());
	}

	needFailover = true;
	}

	SecretKey preMaster;
	if (needFailover) {
	// The cipher might be spoiled by unsuccessful call to init(),
	// so request a fresh instance
	cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);

	// Use DECRYPT_MODE and dispose the previous initialization.
	cipher.init(Cipher.DECRYPT_MODE, privateKey);
	boolean failed = false;
	try {
	encoded = cipher.doFinal(encrypted);
	} catch (BadPaddingException bpe) {
	// Note: encoded == null
	failed = true;
	}
	encoded = KeyUtil.checkTlsPreMasterSecretKey(
	shc.clientHelloVersion, shc.negotiatedProtocol.id,
	shc.sslContext.getSecureRandom(), encoded, failed);
	preMaster = generatePremasterSecret(
	shc.clientHelloVersion, shc.negotiatedProtocol.id,
	encoded, shc.sslContext.getSecureRandom());
	} else {
	// the cipher should have been initialized
	preMaster = (SecretKey)cipher.unwrap(encrypted,
	"TlsRsaPremasterSecret", Cipher.SECRET_KEY);
	}

	return new RSAPremasterSecret(preMaster);
	}

	/*
	* Retrieving the cipher's provider name for the debug purposes
	* can throw an exception by itself.
	*/
	private static String safeProviderName(Cipher cipher) {
	try {
	return cipher.getProvider().toString();
	} catch (Exception e) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine("Retrieving The Cipher provider name" +
	" caused exception ", e);
	}
	}
	try {
	return cipher.toString() + " (provider name not available)";
	} catch (Exception e) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine("Retrieving The Cipher name" +
	" caused exception ", e);
	}
	}

	return "(cipher/provider names not available)";
	}

	// generate a premaster secret with the specified version number
	@SuppressWarnings("deprecation")
	private static SecretKey generatePremasterSecret(
	int clientVersion, int serverVersion, byte[] encodedSecret,
	SecureRandom generator) throws GeneralSecurityException {

	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine("Generating a premaster secret");
	}

	try {
	String s = ((clientVersion >= ProtocolVersion.TLS12.id) ?
	"SunTls12RsaPremasterSecret" : "SunTlsRsaPremasterSecret");
	KeyGenerator kg = JsseJce.getKeyGenerator(s);
	kg.init(new TlsRsaPremasterSecretParameterSpec(
	clientVersion, serverVersion, encodedSecret),
	generator);
	return kg.generateKey();
	} catch (InvalidAlgorithmParameterException \|
	NoSuchAlgorithmException iae) {
	// unlikely to happen, otherwise, must be a provider exception
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine("RSA premaster secret generation error:");
	iae.printStackTrace(System.out);
	}

	throw new GeneralSecurityException(
	"Could not generate premaster secret", iae);
	}
	}
	}

	private static final
	class RSAKAGenerator implements SSLKeyAgreementGenerator {
	// Prevent instantiation of this class.
	private RSAKAGenerator() {
	// blank
	}

	@Override
	public SSLKeyDerivation createKeyDerivation(
	HandshakeContext context) throws IOException {
	RSAPremasterSecret premaster = null;
	if (context instanceof ClientHandshakeContext) {
	for (SSLPossession possession : context.handshakePossessions) {
	if (possession instanceof RSAPremasterSecret) {
	premaster = (RSAPremasterSecret)possession;
	break;
	}
	}
	} else {
	for (SSLCredentials credential : context.handshakeCredentials) {
	if (credential instanceof RSAPremasterSecret) {
	premaster = (RSAPremasterSecret)credential;
	break;
	}
	}
	}

	if (premaster == null) {
	context.conContext.fatal(Alert.HANDSHAKE_FAILURE,
	"No sufficient RSA key agreement parameters negotiated");
	}

	return new RSAKAKeyDerivation(context, premaster.premasterSecret);
	}

	private static final
	class RSAKAKeyDerivation implements SSLKeyDerivation {
	private final HandshakeContext context;
	private final SecretKey preMasterSecret;

	RSAKAKeyDerivation(
	HandshakeContext context, SecretKey preMasterSecret) {
	this.context = context;
	this.preMasterSecret = preMasterSecret;
	}

	@Override
	public SecretKey deriveKey(String algorithm,
	AlgorithmParameterSpec params) throws IOException {
	SSLMasterKeyDerivation mskd =
	SSLMasterKeyDerivation.valueOf(
	context.negotiatedProtocol);
	if (mskd == null) {
	// unlikely
	throw new SSLHandshakeException(
	"No expected master key derivation for protocol: " +
	context.negotiatedProtocol.name);
	}
	SSLKeyDerivation kd = mskd.createKeyDerivation(
	context, preMasterSecret);
	return kd.deriveKey("MasterSecret", params);
	}
	}
	}
	}

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