/*

 * 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

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

 *

 * 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.

 *

 */

package sun.security.jgss.spnego;

import com.sun.security.jgss.ExtendedGSSContext;

import com.sun.security.jgss.InquireType;

import java.io.*;

import java.security.Provider;

import org.ietf.jgss.*;

import sun.security.jgss.*;

import sun.security.jgss.spi.*;

import sun.security.util.*;

/**

 * Implements the mechanism specific context class for SPNEGO

 * GSS-API mechanism

 *

 * @author Seema Malkani

 * @since 1.6

 */

public class SpNegoContext implements GSSContextSpi {

    /*

     * The different states that this context can be in.

     */

    private static final int STATE_NEW = 1;

    private static final int STATE_IN_PROCESS = 2;

    private static final int STATE_DONE = 3;

    private static final int STATE_DELETED = 4;

    private int state = STATE_NEW;

    /*

     * Optional features that the application can set and their default

     * values.

     */

    private boolean credDelegState = false;

    private boolean mutualAuthState = true;

    private boolean replayDetState = true;

    private boolean sequenceDetState = true;

    private boolean confState = true;

    private boolean integState = true;

    private boolean delegPolicyState = false;

    private GSSNameSpi peerName = null;

    private GSSNameSpi myName = null;

    private SpNegoCredElement myCred = null;

    private GSSContext mechContext = null;

    private byte[] DER_mechTypes = null;

    private int lifetime;

    private ChannelBinding channelBinding;

    private boolean initiator;

    // the underlying negotiated mechanism

    private Oid internal_mech = null;

    // the SpNegoMechFactory that creates this context

    final private SpNegoMechFactory factory;

    // debug property

    static final boolean DEBUG =

        java.security.AccessController.doPrivileged(

            new sun.security.action.GetBooleanAction

            ("sun.security.spnego.debug")).booleanValue();

    /**

     * Constructor for SpNegoContext to be called on the context initiator's

     * side.

     */

    public SpNegoContext(SpNegoMechFactory factory, GSSNameSpi peerName,

                        GSSCredentialSpi myCred,

                        int lifetime) throws GSSException {

        if (peerName == null)

            throw new IllegalArgumentException("Cannot have null peer name");

        if ((myCred != null) && !(myCred instanceof SpNegoCredElement)) {

            throw new IllegalArgumentException("Wrong cred element type");

        }

        this.peerName = peerName;

        this.myCred = (SpNegoCredElement) myCred;

        this.lifetime = lifetime;

        this.initiator = true;

        this.factory = factory;

    }

    /**

     * Constructor for SpNegoContext to be called on the context acceptor's

     * side.

     */

    public SpNegoContext(SpNegoMechFactory factory, GSSCredentialSpi myCred)

            throws GSSException {

        if ((myCred != null) && !(myCred instanceof SpNegoCredElement)) {

            throw new IllegalArgumentException("Wrong cred element type");

        }

        this.myCred = (SpNegoCredElement) myCred;

        this.initiator = false;

        this.factory = factory;

    }

    /**

     * Constructor for SpNegoContext to import a previously exported context.

     */

    public SpNegoContext(SpNegoMechFactory factory, byte [] interProcessToken)

        throws GSSException {

        throw new GSSException(GSSException.UNAVAILABLE,

                               -1, "GSS Import Context not available");

    }

    /**

     * Requests that confidentiality be available.

     */

    public final void requestConf(boolean value) throws GSSException {

        if (state == STATE_NEW && isInitiator())

            confState  = value;

    }

    /**

     * Is confidentiality available?

     */

    public final boolean getConfState() {

        return confState;

    }

    /**

     * Requests that integrity be available.

     */

    public final void requestInteg(boolean value) throws GSSException {

        if (state == STATE_NEW && isInitiator())

            integState  = value;

    }

    /**

     * Requests that deleg policy be respected.

     */

    public final void requestDelegPolicy(boolean value) throws GSSException {

        if (state == STATE_NEW && isInitiator())

            delegPolicyState = value;

    }

    /**

     * Is integrity available?

     */

    public final boolean getIntegState() {

        return integState;

    }

    /**

     * Is deleg policy respected?

     */

    public final boolean getDelegPolicyState() {

        if (isInitiator() && mechContext != null &&

                mechContext instanceof ExtendedGSSContext &&

                (state == STATE_IN_PROCESS || state == STATE_DONE)) {

            return ((ExtendedGSSContext)mechContext).getDelegPolicyState();

        } else {

            return delegPolicyState;

        }

    }

    /**

     * Requests that credential delegation be done during context

     * establishment.

     */

    public final void requestCredDeleg(boolean value) throws GSSException {

        if (state == STATE_NEW && isInitiator())

            credDelegState  = value;

    }

    /**

     * Is credential delegation enabled?

     */

    public final boolean getCredDelegState() {

        if (isInitiator() && mechContext != null &&

                (state == STATE_IN_PROCESS || state == STATE_DONE)) {

            return mechContext.getCredDelegState();

        } else {

            return credDelegState;

        }

    }

    /**

     * Requests that mutual authentication be done during context

     * establishment. Since this is fromm the client's perspective, it

     * essentially requests that the server be authenticated.

     */

    public final void requestMutualAuth(boolean value) throws GSSException {

        if (state == STATE_NEW && isInitiator()) {

            mutualAuthState  = value;

        }

    }

    /**

     * Is mutual authentication enabled? Since this is from the client's

     * perspective, it essentially meas that the server is being

     * authenticated.

     */

    public final boolean getMutualAuthState() {

        return mutualAuthState;

    }

    /**

     * Returns the mechanism oid.

     *

     * @return the Oid of this context

     */

    public final Oid getMech() {

        if (isEstablished()) {

            return getNegotiatedMech();

        }

        return (SpNegoMechFactory.GSS_SPNEGO_MECH_OID);

    }

    public final Oid getNegotiatedMech() {

        return (internal_mech);

    }

    public final Provider getProvider() {

        return SpNegoMechFactory.PROVIDER;

    }

    public final void dispose() throws GSSException {

        mechContext = null;

        state = STATE_DELETED;

    }

    /**

     * Tests if this is the initiator side of the context.

     *

     * @return boolean indicating if this is initiator (true)

     *  or target (false)

     */

    public final boolean isInitiator() {

        return initiator;

    }

    /**

     * Tests if the context can be used for per-message service.

     * Context may allow the calls to the per-message service

     * functions before being fully established.

     *

     * @return boolean indicating if per-message methods can

     *  be called.

     */

    public final boolean isProtReady() {

        return (state == STATE_DONE);

    }

    /**

     * Initiator context establishment call. This method may be

     * required to be called several times. A CONTINUE_NEEDED return

     * call indicates that more calls are needed after the next token

     * is received from the peer.

     *

     * @param is contains the token received from the peer. On the

     *        first call it will be ignored.

     * @return any token required to be sent to the peer

     * It is responsibility of the caller to send the token

     * to its peer for processing.

     * @exception GSSException

     */

    public final byte[] initSecContext(InputStream is, int mechTokenSize)

        throws GSSException {

        byte[] retVal = null;

        NegTokenInit initToken = null;

        byte[] mechToken = null;

        int errorCode = GSSException.FAILURE;

        if (DEBUG) {

            System.out.println("Entered SpNego.initSecContext with " +

                                "state=" + printState(state));

        }

        if (!isInitiator()) {

            throw new GSSException(GSSException.FAILURE, -1,

                "initSecContext on an acceptor GSSContext");

        }

        try {

            if (state == STATE_NEW) {

                state = STATE_IN_PROCESS;

                errorCode = GSSException.NO_CRED;

                // determine available mech set

                Oid[] mechList = getAvailableMechs();

                DER_mechTypes = getEncodedMechs(mechList);

                // pull out first mechanism

                internal_mech = mechList[0];

                // get the token for first mechanism

                mechToken = GSS_initSecContext(null);

                errorCode = GSSException.DEFECTIVE_TOKEN;

                // generate SPNEGO token

                initToken = new NegTokenInit(DER_mechTypes, getContextFlags(),

                                        mechToken, null);

                if (DEBUG) {

                    System.out.println("SpNegoContext.initSecContext: " +

                                "sending token of type = " +

                                SpNegoToken.getTokenName(initToken.getType()));

                }

                // get the encoded token

                retVal = initToken.getEncoded();

            } else if (state == STATE_IN_PROCESS) {

                errorCode = GSSException.FAILURE;

                if (is == null) {

                    throw new GSSException(errorCode, -1,

                                "No token received from peer!");

                }

                errorCode = GSSException.DEFECTIVE_TOKEN;

                byte[] server_token = new byte[is.available()];

                SpNegoToken.readFully(is, server_token);

                if (DEBUG) {

                    System.out.println("SpNegoContext.initSecContext: " +

                                        "process received token = " +

                                        SpNegoToken.getHexBytes(server_token));

                }

                // read the SPNEGO token

                // token will be validated when parsing

                NegTokenTarg targToken = new NegTokenTarg(server_token);

                if (DEBUG) {

                    System.out.println("SpNegoContext.initSecContext: " +

                                "received token of type = " +

                                SpNegoToken.getTokenName(targToken.getType()));

                }

                // pull out mechanism

                internal_mech = targToken.getSupportedMech();

                if (internal_mech == null) {

                    // return wth failure

                    throw new GSSException(errorCode, -1,

                                "supported mechansim from server is null");

                }

                // get the negotiated result

                SpNegoToken.NegoResult negoResult = null;

                int result = targToken.getNegotiatedResult();

                switch (result) {

                    case 0:

                        negoResult = SpNegoToken.NegoResult.ACCEPT_COMPLETE;

                        state = STATE_DONE;

                        break;

                    case 1:

                        negoResult = SpNegoToken.NegoResult.ACCEPT_INCOMPLETE;

                        state = STATE_IN_PROCESS;

                        break;

                    case 2:

                        negoResult = SpNegoToken.NegoResult.REJECT;

                        state = STATE_DELETED;

                        break;

                    default:

                        state = STATE_DONE;

                        break;

                }

                errorCode = GSSException.BAD_MECH;

                if (negoResult == SpNegoToken.NegoResult.REJECT) {

                    throw new GSSException(errorCode, -1,

                                        internal_mech.toString());

                }

                errorCode = GSSException.DEFECTIVE_TOKEN;

                if ((negoResult == SpNegoToken.NegoResult.ACCEPT_COMPLETE) ||

                    (negoResult == SpNegoToken.NegoResult.ACCEPT_INCOMPLETE)) {

                    // pull out the mechanism token

                    byte[] accept_token = targToken.getResponseToken();

                    if (accept_token == null) {

                        if (!isMechContextEstablished()) {

                            // return with failure

                            throw new GSSException(errorCode, -1,

                                    "mechanism token from server is null");

                        }

                    } else {

                        mechToken = GSS_initSecContext(accept_token);

                    }

                    // verify MIC

                    if (!GSSUtil.useMSInterop()) {

                        byte[] micToken = targToken.getMechListMIC();

                        if (!verifyMechListMIC(DER_mechTypes, micToken)) {

                            throw new GSSException(errorCode, -1,

                                "verification of MIC on MechList Failed!");

                        }

                    }

                    if (isMechContextEstablished()) {

                        state = STATE_DONE;

                        retVal = mechToken;

                        if (DEBUG) {

                            System.out.println("SPNEGO Negotiated Mechanism = "

                                + internal_mech + " " +

                                GSSUtil.getMechStr(internal_mech));

                        }

                    } else {

                        // generate SPNEGO token

                        initToken = new NegTokenInit(null, null,

                                                mechToken, null);

                        if (DEBUG) {

                            System.out.println("SpNegoContext.initSecContext:" +

                                " continue sending token of type = " +

                                SpNegoToken.getTokenName(initToken.getType()));

                        }

                        // get the encoded token

                        retVal = initToken.getEncoded();

                    }

                }

            } else {

                // XXX Use logging API

                if (DEBUG) {

                    System.out.println(state);

                }

            }

            if (DEBUG) {

                if (retVal != null) {

                    System.out.println("SNegoContext.initSecContext: " +

                        "sending token = " + SpNegoToken.getHexBytes(retVal));

                }

            }

        } catch (GSSException e) {

            GSSException gssException =

                        new GSSException(errorCode, -1, e.getMessage());

            gssException.initCause(e);

            throw gssException;

        } catch (IOException e) {

            GSSException gssException =

                new GSSException(GSSException.FAILURE, -1, e.getMessage());

            gssException.initCause(e);

            throw gssException;

        }

        return retVal;

    }

    /**

     * Acceptor's context establishment call. This method may be

     * required to be called several times. A CONTINUE_NEEDED return

     * call indicates that more calls are needed after the next token

     * is received from the peer.

     *

     * @param is contains the token received from the peer.

     * @return any token required to be sent to the peer

     * It is responsibility of the caller to send the token

     * to its peer for processing.

     * @exception GSSException

     */

    public final byte[] acceptSecContext(InputStream is, int mechTokenSize)

        throws GSSException {

        byte[] retVal = null;

        SpNegoToken.NegoResult negoResult;

        boolean valid = true;

        if (DEBUG) {

            System.out.println("Entered SpNegoContext.acceptSecContext with " +

                               "state=" +  printState(state));

        }

        if (isInitiator()) {

            throw new GSSException(GSSException.FAILURE, -1,

                                   "acceptSecContext on an initiator " +

                                   "GSSContext");

        }

        try {

            if (state == STATE_NEW) {

                state = STATE_IN_PROCESS;

                // read data

                byte[] token = new byte[is.available()];

                SpNegoToken.readFully(is, token);

                if (DEBUG) {

                    System.out.println("SpNegoContext.acceptSecContext: " +

                                        "receiving token = " +

                                        SpNegoToken.getHexBytes(token));

                }

                // read the SPNEGO token

                // token will be validated when parsing

                NegTokenInit initToken = new NegTokenInit(token);

                if (DEBUG) {

                    System.out.println("SpNegoContext.acceptSecContext: " +

                                "received token of type = " +

                                SpNegoToken.getTokenName(initToken.getType()));

                }

                Oid[] mechList = initToken.getMechTypeList();

                DER_mechTypes = initToken.getMechTypes();

                if (DER_mechTypes == null) {

                    valid = false;

                }