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 * Copyright (c) 1996, 2016, 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

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package sun.security.ssl;

import java.io.*;

import java.security.*;

import javax.crypto.*;

import javax.net.ssl.*;

import sun.security.internal.spec.TlsRsaPremasterSecretParameterSpec;

import sun.security.util.KeyUtil;

/**

 * This is the client key exchange message (CLIENT --> SERVER) used with

 * all RSA key exchanges; it holds the RSA-encrypted pre-master secret.

 *

 * The message is encrypted using PKCS #1 block type 02 encryption with the

 * server's public key.  The padding and resulting message size is a function

 * of this server's public key modulus size, but the pre-master secret is

 * always exactly 48 bytes.

 *

 */

final class RSAClientKeyExchange extends HandshakeMessage {

    /*

     * The following field values were encrypted with the server's public

     * key (or temp key from server key exchange msg) and are presented

     * here in DECRYPTED form.

     */

    private ProtocolVersion protocolVersion; // preMaster [0,1]

    SecretKey preMaster;

    private byte[] encrypted;           // same size as public modulus

    /*

     * Client randomly creates a pre-master secret and encrypts it

     * using the server's RSA public key; only the server can decrypt

     * it, using its RSA private key.  Result is the same size as the

     * server's public key, and uses PKCS #1 block format 02.

     */

    @SuppressWarnings("deprecation")

    RSAClientKeyExchange(ProtocolVersion protocolVersion,

            ProtocolVersion maxVersion,

            SecureRandom generator, PublicKey publicKey) throws IOException {

        if (publicKey.getAlgorithm().equals("RSA") == false) {

            throw new SSLKeyException("Public key not of type RSA: " +

                publicKey.getAlgorithm());

        }

        this.protocolVersion = protocolVersion;

        try {

            String s = protocolVersion.useTLS12PlusSpec() ?

                "SunTls12RsaPremasterSecret" : "SunTlsRsaPremasterSecret";

            KeyGenerator kg = JsseJce.getKeyGenerator(s);

            kg.init(new TlsRsaPremasterSecretParameterSpec(

                    maxVersion.v, protocolVersion.v), generator);

            preMaster = kg.generateKey();

            Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);

            cipher.init(Cipher.WRAP_MODE, publicKey, generator);

            encrypted = cipher.wrap(preMaster);

        } catch (GeneralSecurityException e) {

            throw (SSLKeyException)new SSLKeyException

                                ("RSA premaster secret error").initCause(e);

        }

    }

    /*

     * 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 (debug != null && Debug.isOn("handshake")) {

                System.out.println("Retrieving The Cipher provider name" +

                        " caused exception " + e.getMessage());

            }

        }

        try {

            return cipher.toString() + " (provider name not available)";

        } catch (Exception e) {

            if (debug != null && Debug.isOn("handshake")) {

                System.out.println("Retrieving The Cipher name" +

                        " caused exception " + e.getMessage());

            }

        }

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

    }

    /*

     * Server gets the PKCS #1 (block format 02) data, decrypts

     * it with its private key.

     */

    @SuppressWarnings("deprecation")

    RSAClientKeyExchange(ProtocolVersion currentVersion,

            ProtocolVersion maxVersion,

            SecureRandom generator, HandshakeInStream input,

            int messageSize, PrivateKey privateKey) throws IOException {

        if (privateKey.getAlgorithm().equals("RSA") == false) {

            throw new SSLKeyException("Private key not of type RSA: " +

                 privateKey.getAlgorithm());

        }

        if (currentVersion.useTLS10PlusSpec()) {

            encrypted = input.getBytes16();

        } else {

            encrypted = new byte [messageSize];

            if (input.read(encrypted) != messageSize) {

                throw new SSLProtocolException(

                        "SSL: read PreMasterSecret: short read");

            }

        }

        byte[] encoded = null;

        try {

            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(

                                maxVersion.v, currentVersion.v),

                        generator);

                // 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 (debug != null && Debug.isOn("handshake")) {

                    System.out.println("The Cipher provider "

                            + safeProviderName(cipher)

                            + " caused exception: " + iue.getMessage());

                }

                needFailover = true;

            }

            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(

                                maxVersion.v, currentVersion.v,

                                generator, encoded, failed);

                preMaster = generatePreMasterSecret(

                                maxVersion.v, currentVersion.v,

                                encoded, generator);

            } else {

                // the cipher should have been initialized

                preMaster = (SecretKey)cipher.unwrap(encrypted,

                        "TlsRsaPremasterSecret", Cipher.SECRET_KEY);

            }

        } catch (InvalidKeyException ibk) {

            // the message is too big to process with RSA

            throw new SSLException(

                "Unable to process PreMasterSecret", ibk);

        } catch (Exception e) {

            // unlikely to happen, otherwise, must be a provider exception

            if (debug != null && Debug.isOn("handshake")) {

                System.out.println("RSA premaster secret decryption error:");

                e.printStackTrace(System.out);

            }

            throw new RuntimeException("Could not generate dummy secret", e);

        }

    }

    // generate a premaster secret with the specified version number

    @SuppressWarnings("deprecation")

    private static SecretKey generatePreMasterSecret(

            int clientVersion, int serverVersion,

            byte[] encodedSecret, SecureRandom generator) {

        if (debug != null && Debug.isOn("handshake")) {

            System.out.println("Generating a premaster secret");

        }

        try {

            String s = ((clientVersion >= ProtocolVersion.TLS12.v) ?

                "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 (debug != null && Debug.isOn("handshake")) {

                System.out.println("RSA premaster secret generation error:");

                iae.printStackTrace(System.out);

            }

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

        }

    }

    @Override

    int messageType() {

        return ht_client_key_exchange;

    }

    @Override

    int messageLength() {

        if (protocolVersion.useTLS10PlusSpec()) {

            return encrypted.length + 2;

        } else {

            return encrypted.length;

        }

    }

    @Override

    void send(HandshakeOutStream s) throws IOException {

        if (protocolVersion.useTLS10PlusSpec()) {

            s.putBytes16(encrypted);

        } else {

            s.write(encrypted);

        }

    }

    @Override

    void print(PrintStream s) throws IOException {

        String version = "version not available/extractable";

        byte[] ba = preMaster.getEncoded();

        if (ba != null && ba.length >= 2) {

            version = ProtocolVersion.valueOf(ba[0], ba[1]).name;

        }

        s.println("*** ClientKeyExchange, RSA PreMasterSecret, " + version);

    }

}