/*

 * 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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

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 */

package sun.security.ssl;

import java.io.*;

import java.math.BigInteger;

import java.security.*;

import java.util.*;

import java.security.interfaces.ECPublicKey;

import java.security.interfaces.RSAPublicKey;

import java.security.spec.ECParameterSpec;

import java.security.cert.X509Certificate;

import java.security.cert.CertificateException;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

import javax.net.ssl.*;

import javax.security.auth.Subject;

import javax.security.auth.kerberos.KerberosPrincipal;

import sun.security.jgss.krb5.Krb5Util;

import sun.security.jgss.GSSUtil;

import com.sun.net.ssl.internal.ssl.X509ExtendedTrustManager;

import sun.security.ssl.HandshakeMessage.*;

import sun.security.ssl.CipherSuite.*;

import static sun.security.ssl.CipherSuite.*;

import static sun.security.ssl.CipherSuite.KeyExchange.*;

/**

 * ClientHandshaker does the protocol handshaking from the point

 * of view of a client.  It is driven asychronously by handshake messages

 * as delivered by the parent Handshaker class, and also uses

 * common functionality (e.g. key generation) that is provided there.

 *

 * @author David Brownell

 */

final class ClientHandshaker extends Handshaker {

    // the server's public key from its certificate.

    private PublicKey serverKey;

    // the server's ephemeral public key from the server key exchange message

    // for ECDHE/ECDH_anon and RSA_EXPORT.

    private PublicKey ephemeralServerKey;

    // server's ephemeral public value for DHE/DH_anon key exchanges

    private BigInteger          serverDH;

    private DHCrypt             dh;

    private ECDHCrypt ecdh;

    private CertificateRequest  certRequest;

    private boolean serverKeyExchangeReceived;

    /*

     * The RSA PreMasterSecret needs to know the version of

     * ClientHello that was used on this handshake.  This represents

     * the "max version" this client is supporting.  In the

     * case of an initial handshake, it's the max version enabled,

     * but in the case of a resumption attempt, it's the version

     * of the session we're trying to resume.

     */

    private ProtocolVersion maxProtocolVersion;

    /*

     * Constructors

     */

    ClientHandshaker(SSLSocketImpl socket, SSLContextImpl context,

            ProtocolList enabledProtocols) {

        super(socket, context, enabledProtocols, true, true);

    }

    ClientHandshaker(SSLEngineImpl engine, SSLContextImpl context,

            ProtocolList enabledProtocols) {

        super(engine, context, enabledProtocols, true, true);

    }

    /*

     * This routine handles all the client side handshake messages, one at

     * a time.  Given the message type (and in some cases the pending cipher

     * spec) it parses the type-specific message.  Then it calls a function

     * that handles that specific message.

     *

     * It updates the state machine (need to verify it) as each message

     * is processed, and writes responses as needed using the connection

     * in the constructor.

     */

    void processMessage(byte type, int messageLen) throws IOException {

        if (state > type

                && (type != HandshakeMessage.ht_hello_request

                    && state != HandshakeMessage.ht_client_hello)) {

            throw new SSLProtocolException(

                    "Handshake message sequence violation, " + type);

        }

        switch (type) {

        case HandshakeMessage.ht_hello_request:

            this.serverHelloRequest(new HelloRequest(input));

            break;

        case HandshakeMessage.ht_server_hello:

            this.serverHello(new ServerHello(input, messageLen));

            break;

        case HandshakeMessage.ht_certificate:

            if (keyExchange == K_DH_ANON || keyExchange == K_ECDH_ANON

                    || keyExchange == K_KRB5 || keyExchange == K_KRB5_EXPORT) {

                fatalSE(Alerts.alert_unexpected_message,

                    "unexpected server cert chain");

                // NOTREACHED

            }

            this.serverCertificate(new CertificateMsg(input));

            serverKey =

                session.getPeerCertificates()[0].getPublicKey();

            break;

        case HandshakeMessage.ht_server_key_exchange:

            serverKeyExchangeReceived = true;

            switch (keyExchange) {

            case K_RSA_EXPORT:

                /**

                 * The server key exchange message is sent by the server only

                 * when the server certificate message does not contain the

                 * proper amount of data to allow the client to exchange a

                 * premaster secret, such as when RSA_EXPORT is used and the

                 * public key in the server certificate is longer than 512 bits.

                 */

                if (serverKey == null) {

                    throw new SSLProtocolException

                        ("Server did not send certificate message");

                }

                if (!(serverKey instanceof RSAPublicKey)) {

                    throw new SSLProtocolException("Protocol violation:" +

                        " the certificate type must be appropriate for the" +

                        " selected cipher suite's key exchange algorithm");

                }

                if (JsseJce.getRSAKeyLength(serverKey) <= 512) {

                    throw new SSLProtocolException("Protocol violation:" +

                        " server sent a server key exchange message for" +

                        " key exchange " + keyExchange +

                        " when the public key in the server certificate" +

                        " is less than or equal to 512 bits in length");

                }

                try {

                    this.serverKeyExchange(new RSA_ServerKeyExchange(input));

                } catch (GeneralSecurityException e) {

                    throwSSLException("Server key", e);

                }

                break;

            case K_DH_ANON:

                this.serverKeyExchange(new DH_ServerKeyExchange(input));

                break;

            case K_DHE_DSS:

            case K_DHE_RSA:

                try {

                    this.serverKeyExchange(new DH_ServerKeyExchange(

                        input, serverKey,

                        clnt_random.random_bytes, svr_random.random_bytes,

                        messageLen));

                } catch (GeneralSecurityException e) {

                    throwSSLException("Server key", e);

                }

                break;

            case K_ECDHE_ECDSA:

            case K_ECDHE_RSA:

            case K_ECDH_ANON:

                try {

                    this.serverKeyExchange(new ECDH_ServerKeyExchange

                        (input, serverKey, clnt_random.random_bytes,

                        svr_random.random_bytes));

                } catch (GeneralSecurityException e) {

                    throwSSLException("Server key", e);

                }

                break;

            case K_RSA:

            case K_DH_RSA:

            case K_DH_DSS:

            case K_ECDH_ECDSA:

            case K_ECDH_RSA:

                throw new SSLProtocolException("Protocol violation: server sent"

                    + " a server key exchange message for key exchange " + keyExchange);

            case K_KRB5:

            case K_KRB5_EXPORT:

                throw new SSLProtocolException(

                    "unexpected receipt of server key exchange algorithm");

            default:

                throw new SSLProtocolException(

                    "unsupported key exchange algorithm = "

                    + keyExchange);

            }

            break;

        case HandshakeMessage.ht_certificate_request:

            // save for later, it's handled by serverHelloDone

            if ((keyExchange == K_DH_ANON) || (keyExchange == K_ECDH_ANON)) {

                throw new SSLHandshakeException(

                    "Client authentication requested for "+

                    "anonymous cipher suite.");

            } else if (keyExchange == K_KRB5 || keyExchange == K_KRB5_EXPORT) {

                throw new SSLHandshakeException(

                    "Client certificate requested for "+

                    "kerberos cipher suite.");

            }

            certRequest = new CertificateRequest(input);

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

                certRequest.print(System.out);

            }

            break;

        case HandshakeMessage.ht_server_hello_done:

            this.serverHelloDone(new ServerHelloDone(input));

            break;

        case HandshakeMessage.ht_finished:

            this.serverFinished(new Finished(protocolVersion, input));

            break;

        default:

            throw new SSLProtocolException(

                "Illegal client handshake msg, " + type);

        }

        //

        // Move state machine forward if the message handling

        // code didn't already do so

        //

        if (state < type) {

            state = type;

        }

    }

    /*

     * Used by the server to kickstart negotiations -- this requests a

     * "client hello" to renegotiate current cipher specs (e.g. maybe lots

     * of data has been encrypted with the same keys, or the server needs

     * the client to present a certificate).

     */

    private void serverHelloRequest(HelloRequest mesg) throws IOException {

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

            mesg.print(System.out);

        }

        //

        // Could be (e.g. at connection setup) that we already

        // sent the "client hello" but the server's not seen it.

        //

        if (state < HandshakeMessage.ht_client_hello) {

            kickstart();

        }

    }

    /*

     * Server chooses session parameters given options created by the

     * client -- basically, cipher options, session id, and someday a

     * set of compression options.

     *

     * There are two branches of the state machine, decided by the

     * details of this message.  One is the "fast" handshake, where we

     * can resume the pre-existing session we asked resume.  The other

     * is a more expensive "full" handshake, with key exchange and

     * probably authentication getting done.

     */

    private void serverHello(ServerHello mesg) throws IOException {

        serverKeyExchangeReceived = false;

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

            mesg.print(System.out);

        }

        // check if the server selected protocol version is OK for us

        ProtocolVersion mesgVersion = mesg.protocolVersion;

        if (enabledProtocols.contains(mesgVersion) == false) {

            throw new SSLHandshakeException

            ("Server chose unsupported or disabled protocol: " + mesgVersion);

        }

        // Set protocolVersion and propagate to SSLSocket and the

        // Handshake streams

        setVersion(mesgVersion);

        //

        // Save server nonce, we always use it to compute connection

        // keys and it's also used to create the master secret if we're

        // creating a new session (i.e. in the full handshake).

        //

        svr_random = mesg.svr_random;

        if (isEnabled(mesg.cipherSuite) == false) {

            fatalSE(Alerts.alert_illegal_parameter,

                "Server selected disabled ciphersuite " + cipherSuite);

        }

        setCipherSuite(mesg.cipherSuite);

        if (mesg.compression_method != 0) {

            fatalSE(Alerts.alert_illegal_parameter,

                "compression type not supported, "

                + mesg.compression_method);

            // NOTREACHED

        }

        // so far so good, let's look at the session

        if (session != null) {

            // we tried to resume, let's see what the server decided

            if (session.getSessionId().equals(mesg.sessionId)) {

                // server resumed the session, let's make sure everything

                // checks out

                // Verify that the session ciphers are unchanged.

                CipherSuite sessionSuite = session.getSuite();

                if (cipherSuite != sessionSuite) {

                    throw new SSLProtocolException

                        ("Server returned wrong cipher suite for session");

                }

                // verify protocol version match

                ProtocolVersion sessionVersion = session.getProtocolVersion();

                if (protocolVersion != sessionVersion) {

                    throw new SSLProtocolException

                        ("Server resumed session with wrong protocol version");

                }

                // validate subject identity

                if (sessionSuite.keyExchange == K_KRB5 ||

                    sessionSuite.keyExchange == K_KRB5_EXPORT) {

                    Principal localPrincipal = session.getLocalPrincipal();

                    Subject subject = null;

                    try {

                        subject = AccessController.doPrivileged(

                            new PrivilegedExceptionAction<Subject>() {

                            public Subject run() throws Exception {

                                return Krb5Util.getSubject(

                                    GSSUtil.CALLER_SSL_CLIENT,

                                    getAccSE());

                            }});

                    } catch (PrivilegedActionException e) {

                        subject = null;

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

                            System.out.println("Attempt to obtain" +

                                        " subject failed!");

                        }

                    }

                    if (subject != null) {

                        Set<KerberosPrincipal> principals =

                                subject.getPrincipals(KerberosPrincipal.class);

                        if (!principals.contains(localPrincipal)) {

                            throw new SSLProtocolException("Server resumed" +

                                " session with wrong subject identity");

                        } else {

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

                                System.out.println("Subject identity is same");

                        }

                    } else {

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

                            System.out.println("Kerberos credentials are not" +

                                " present in the current Subject; check if " +

                                " javax.security.auth.useSubjectAsCreds" +

                                " system property has been set to false");

                        throw new SSLProtocolException

                            ("Server resumed session with no subject");

                    }

                }

                // looks fine; resume it, and update the state machine.

                resumingSession = true;

                state = HandshakeMessage.ht_finished - 1;

                calculateConnectionKeys(session.getMasterSecret());

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

                    System.out.println("%% Server resumed " + session);

                }

                return;

            } else {

                // we wanted to resume, but the server refused

                session = null;

                if (!enableNewSession) {

                    throw new SSLException

                        ("New session creation is disabled");

                }

            }

        }

        // check extensions

        for (HelloExtension ext : mesg.extensions.list()) {

            ExtensionType type = ext.type;

            if ((type != ExtensionType.EXT_ELLIPTIC_CURVES)

                    && (type != ExtensionType.EXT_EC_POINT_FORMATS)) {

                fatalSE(Alerts.alert_unsupported_extension,

                    "Server sent an unsupported extension: " + type);

            }

        }

        // Create a new session, we need to do the full handshake

        session = new SSLSessionImpl(protocolVersion, cipherSuite,

                            mesg.sessionId, getHostSE(), getPortSE());

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

            System.out.println("** " + cipherSuite);

        }

    }

    /*

     * Server's own key was either a signing-only key, or was too

     * large for export rules ... this message holds an ephemeral

     * RSA key to use for key exchange.

     */

    private void serverKeyExchange(RSA_ServerKeyExchange mesg)

            throws IOException, GeneralSecurityException {

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

            mesg.print(System.out);

        }

        if (!mesg.verify(serverKey, clnt_random, svr_random)) {

            fatalSE(Alerts.alert_handshake_failure,

                "server key exchange invalid");

            // NOTREACHED

        }

        ephemeralServerKey = mesg.getPublicKey();

    }

    /*

     * Diffie-Hellman key exchange.  We save the server public key and

     * our own D-H algorithm object so we can defer key calculations

     * until after we've sent the client key exchange message (which

     * gives client and server some useful parallelism).

     */

    private void serverKeyExchange(DH_ServerKeyExchange mesg)

            throws IOException {

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

            mesg.print(System.out);

        }

        dh = new DHCrypt(mesg.getModulus(), mesg.getBase(), sslContext.getSecureRandom());

        serverDH = mesg.getServerPublicKey();

    }

    private void serverKeyExchange(ECDH_ServerKeyExchange mesg) throws IOException {

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

            mesg.print(System.out);

        }

        ECPublicKey key = mesg.getPublicKey();

        ecdh = new ECDHCrypt(key.getParams(), sslContext.getSecureRandom());

        ephemeralServerKey = key;

    }

    /*

     * The server's "Hello Done" message is the client's sign that

     * it's time to do all the hard work.

     */

    private void serverHelloDone(ServerHelloDone mesg) throws IOException {

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

            mesg.print(System.out);

        }

        /*

         * Always make sure the input has been digested before we

         * start emitting data, to ensure the hashes are correctly

         * computed for the Finished and CertificateVerify messages

         * which we send (here).

         */

        input.digestNow();

        /*

         * FIRST ... if requested, send an appropriate Certificate chain

         * to authenticate the client, and remember the associated private

         * key to sign the CertificateVerify message.

         */

        PrivateKey signingKey = null;

        if (certRequest != null) {

            X509ExtendedKeyManager km = sslContext.getX509KeyManager();

            ArrayList<String> keytypesTmp = new ArrayList<String>(4);

            for (int i = 0; i < certRequest.types.length; i++) {

                String typeName;

                switch (certRequest.types[i]) {

                case CertificateRequest.cct_rsa_sign:

                    typeName = "RSA";

                    break;

                case CertificateRequest.cct_dss_sign:

                    typeName = "DSA";

                    break;

                case CertificateRequest.cct_ecdsa_sign:

                    // ignore if we do not have EC crypto available

                    typeName = JsseJce.isEcAvailable() ? "EC" : null;

                    break;

                // Fixed DH/ECDH client authentication not supported

                case CertificateRequest.cct_rsa_fixed_dh:

                case CertificateRequest.cct_dss_fixed_dh:

                case CertificateRequest.cct_rsa_fixed_ecdh: