/*

 * Copyright 2000-2009 Sun Microsystems, Inc.  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.  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

 * have any questions.

 */

package sun.security.jgss;

import org.ietf.jgss.*;

import sun.security.jgss.spi.*;

import sun.security.util.ObjectIdentifier;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import com.sun.security.jgss.*;

/**

 * This class represents the JGSS security context and its associated

 * operations.  JGSS security contexts are established between

 * peers using locally established credentials.  Multiple contexts

 * may exist simultaneously between a pair of peers, using the same

 * or different set of credentials.  The JGSS is independent of

 * the underlying transport protocols and depends on its callers to

 * transport the tokens between peers.

 * <p>

 * The context object can be thought of as having 3 implicit states:

 * before it is established, during its context establishment, and

 * after a fully established context exists.

 * <p>

 * Before the context establishment phase is initiated, the context

 * initiator may request specific characteristics desired of the

 * established context. These can be set using the set methods. After the

 * context is established, the caller can check the actual characteristic

 * and services offered by the context using the query methods.

 * <p>

 * The context establishment phase begins with the first call to the

 * initSecContext method by the context initiator. During this phase the

 * initSecContext and acceptSecContext methods will produce GSS-API

 * authentication tokens which the calling application needs to send to its

 * peer. The initSecContext and acceptSecContext methods may

 * return a CONTINUE_NEEDED code which indicates that a token is needed

 * from its peer in order to continue the context establishment phase. A

 * return code of COMPLETE signals that the local end of the context is

 * established. This may still require that a token be sent to the peer,

 * depending if one is produced by GSS-API. The isEstablished method can

 * also be used to determine if the local end of the context has been

 * fully established. During the context establishment phase, the

 * isProtReady method may be called to determine if the context can be

 * used for the per-message operations. This allows implementation to

 * use per-message operations on contexts which aren't fully established.

 * <p>

 * After the context has been established or the isProtReady method

 * returns "true", the query routines can be invoked to determine the actual

 * characteristics and services of the established context. The

 * application can also start using the per-message methods of wrap and

 * getMIC to obtain cryptographic operations on application supplied data.

 * <p>

 * When the context is no longer needed, the application should call

 * dispose to release any system resources the context may be using.

 * <DL><DT><B>RFC 2078</b>

 *    <DD>This class corresponds to the context level calls together with

 * the per message calls of RFC 2078. The gss_init_sec_context and

 * gss_accept_sec_context calls have been made simpler by only taking

 * required parameters.  The context can have its properties set before

 * the first call to initSecContext. The supplementary status codes for the

 * per-message operations are returned in an instance of the MessageProp

 * class, which is used as an argument in these calls.</dl>

 */

class GSSContextImpl implements ExtendedGSSContext {

    // private flags for the context state

    private static final int PRE_INIT = 1;

    private static final int IN_PROGRESS = 2;

    private static final int READY = 3;

    private static final int DELETED = 4;

    // instance variables

    private int currentState = PRE_INIT;

    private GSSContextSpi mechCtxt = null;

    private Oid mechOid = null;

    private ObjectIdentifier objId = null;

    private GSSCredentialImpl myCred = null;

    private GSSNameImpl srcName = null;

    private GSSNameImpl targName = null;

    private int reqLifetime = INDEFINITE_LIFETIME;

    private ChannelBinding channelBindings = null;

    private boolean reqConfState = true;

    private boolean reqIntegState = true;

    private boolean reqMutualAuthState = true;

    private boolean reqReplayDetState = true;

    private boolean reqSequenceDetState = true;

    private boolean reqCredDelegState = false;

    private boolean reqAnonState = false;

    /**

     * Creates a GSSContextImp on the context initiator's side.

     */

    public GSSContextImpl(GSSManagerImpl gssManager, GSSName peer, Oid mech,

                          GSSCredential myCred, int lifetime)

        throws GSSException {

        if ((peer == null) || !(peer instanceof GSSNameImpl)) {

            throw new GSSException(GSSException.BAD_NAME);

        }

        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        this.gssManager = gssManager;

        this.myCred = (GSSCredentialImpl) myCred;  // XXX Check first

        reqLifetime = lifetime;

        targName = (GSSNameImpl)peer;

        this.mechOid = mech;

        initiator = true;

    }

    /**

     * Creates a GSSContextImpl on the context acceptor's side.

     */

    public GSSContextImpl(GSSManagerImpl gssManager, GSSCredential myCred)

        throws GSSException {

        this.gssManager = gssManager;

        this.myCred = (GSSCredentialImpl) myCred; // XXX Check first

        initiator = false;

    }

    /**

     * Creates a GSSContextImpl out of a previously exported

     * GSSContext.

     *

     * @see #isTransferable

     */

    public GSSContextImpl(GSSManagerImpl gssManager, byte[] interProcessToken)

        throws GSSException {

        this.gssManager = gssManager;

        mechCtxt = gssManager.getMechanismContext(interProcessToken);

        initiator = mechCtxt.isInitiator();

        this.mechOid = mechCtxt.getMech();

    }

    public byte[] initSecContext(byte inputBuf[], int offset, int len)

        throws GSSException {

        /*

         * Size of ByteArrayOutputStream will double each time that extra

         * bytes are to be written. Usually, without delegation, a GSS

         * initial token containing the Kerberos AP-REQ is between 400 and

         * 600 bytes.

         */

        ByteArrayOutputStream bos = new ByteArrayOutputStream(600);

        ByteArrayInputStream bin =

            new ByteArrayInputStream(inputBuf, offset, len);

        int size = initSecContext(bin, bos);

        return (size == 0? null : bos.toByteArray());

    }

    public int initSecContext(InputStream inStream,

                              OutputStream outStream) throws GSSException {

        if (mechCtxt != null && currentState != IN_PROGRESS) {

            throw new GSSExceptionImpl(GSSException.FAILURE,

                                   "Illegal call to initSecContext");

        }

        GSSHeader gssHeader = null;

        int inTokenLen = -1;

        GSSCredentialSpi credElement = null;

        boolean firstToken = false;

        try {

            if (mechCtxt == null) {

                if (myCred != null) {

                    try {

                        credElement = myCred.getElement(mechOid, true);

                    } catch (GSSException ge) {

                        if (GSSUtil.isSpNegoMech(mechOid) &&

                            ge.getMajor() == GSSException.NO_CRED) {

                            credElement = myCred.getElement

                                (myCred.getMechs()[0], true);

                        } else {

                            throw ge;

                        }

                    }

                }

                GSSNameSpi nameElement = targName.getElement(mechOid);

                mechCtxt = gssManager.getMechanismContext(nameElement,

                                                          credElement,

                                                          reqLifetime,

                                                          mechOid);

                mechCtxt.requestConf(reqConfState);

                mechCtxt.requestInteg(reqIntegState);

                mechCtxt.requestCredDeleg(reqCredDelegState);

                mechCtxt.requestMutualAuth(reqMutualAuthState);

                mechCtxt.requestReplayDet(reqReplayDetState);

                mechCtxt.requestSequenceDet(reqSequenceDetState);

                mechCtxt.requestAnonymity(reqAnonState);

                mechCtxt.setChannelBinding(channelBindings);

                objId = new ObjectIdentifier(mechOid.toString());

                currentState = IN_PROGRESS;

                firstToken = true;

            } else {

                if (mechCtxt.getProvider().getName().equals("SunNativeGSS") ||

                    GSSUtil.isSpNegoMech(mechOid)) {

                    // do not parse GSS header for native provider or SPNEGO

                    // mech

                } else {

                    // parse GSS header

                    gssHeader = new GSSHeader(inStream);

                    if (!gssHeader.getOid().equals((Object) objId))

                        throw new GSSExceptionImpl

                            (GSSException.DEFECTIVE_TOKEN,

                             "Mechanism not equal to " +

                             mechOid.toString() +

                             " in initSecContext token");

                    inTokenLen = gssHeader.getMechTokenLength();

                }

            }

            byte[] obuf = mechCtxt.initSecContext(inStream, inTokenLen);

            int retVal = 0;

            if (obuf != null) {

                retVal = obuf.length;

                if (mechCtxt.getProvider().getName().equals("SunNativeGSS") ||

                    (!firstToken && GSSUtil.isSpNegoMech(mechOid))) {

                    // do not add GSS header for native provider or SPNEGO

                    // except for the first SPNEGO token

                } else {

                    // add GSS header

                    gssHeader = new GSSHeader(objId, obuf.length);

                    retVal += gssHeader.encode(outStream);

                }

                outStream.write(obuf);

            }

            if (mechCtxt.isEstablished())

                currentState = READY;

            return retVal;

        } catch (IOException e) {

            throw new GSSExceptionImpl(GSSException.DEFECTIVE_TOKEN,

                                   e.getMessage());

        }

    }

    public byte[] acceptSecContext(byte inTok[], int offset, int len)

        throws GSSException {

        /*

         * Usually initial GSS token containing a Kerberos AP-REP is less

         * than 100 bytes.

         */

        ByteArrayOutputStream bos = new ByteArrayOutputStream(100);

        acceptSecContext(new ByteArrayInputStream(inTok, offset, len),

                         bos);

        byte[] out = bos.toByteArray();

        return (out.length == 0) ? null : out;

    }

    public void acceptSecContext(InputStream inStream,

                                 OutputStream outStream) throws GSSException {

        if (mechCtxt != null && currentState != IN_PROGRESS) {

            throw new GSSExceptionImpl(GSSException.FAILURE,

                                       "Illegal call to acceptSecContext");

        }

        GSSHeader gssHeader = null;

        int inTokenLen = -1;

        GSSCredentialSpi credElement = null;

        try {

            if (mechCtxt == null) {

                // mechOid will be null for an acceptor's context

                gssHeader = new GSSHeader(inStream);

                inTokenLen = gssHeader.getMechTokenLength();

                /*

                 * Convert ObjectIdentifier to Oid

                 */

                objId = gssHeader.getOid();

                mechOid = new Oid(objId.toString());

                // System.out.println("Entered GSSContextImpl.acceptSecContext"

                //                      + " with mechanism = " + mechOid);

                if (myCred != null) {

                    credElement = myCred.getElement(mechOid, false);

                }

                mechCtxt = gssManager.getMechanismContext(credElement,

                                                          mechOid);

                mechCtxt.setChannelBinding(channelBindings);

                currentState = IN_PROGRESS;

            } else {

                if (mechCtxt.getProvider().getName().equals("SunNativeGSS") ||

                    (GSSUtil.isSpNegoMech(mechOid))) {

                    // do not parse GSS header for native provider and SPNEGO

                } else {

                    // parse GSS Header

                    gssHeader = new GSSHeader(inStream);

                    if (!gssHeader.getOid().equals((Object) objId))

                        throw new GSSExceptionImpl

                            (GSSException.DEFECTIVE_TOKEN,

                             "Mechanism not equal to " +

                             mechOid.toString() +

                             " in acceptSecContext token");

                    inTokenLen = gssHeader.getMechTokenLength();

                }

            }

            byte[] obuf = mechCtxt.acceptSecContext(inStream, inTokenLen);

            if (obuf != null) {

                int retVal = obuf.length;

                if (mechCtxt.getProvider().getName().equals("SunNativeGSS") ||

                    (GSSUtil.isSpNegoMech(mechOid))) {

                    // do not add GSS header for native provider and SPNEGO

                } else {

                    // add GSS header

                    gssHeader = new GSSHeader(objId, obuf.length);

                    retVal += gssHeader.encode(outStream);

                }

                outStream.write(obuf);

            }

            if (mechCtxt.isEstablished()) {

                currentState = READY;

            }

        } catch (IOException e) {

            throw new GSSExceptionImpl(GSSException.DEFECTIVE_TOKEN,

                                   e.getMessage());

        }

    }

    public boolean isEstablished() {

        if (mechCtxt == null)

            return false;

        else

            return (currentState == READY);

    }

    public int getWrapSizeLimit(int qop, boolean confReq,

                                int maxTokenSize) throws GSSException {

        if (mechCtxt != null)

            return mechCtxt.getWrapSizeLimit(qop, confReq, maxTokenSize);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public byte[] wrap(byte inBuf[], int offset, int len,

                       MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            return mechCtxt.wrap(inBuf, offset, len, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                   "No mechanism context yet!");

    }

    public void wrap(InputStream inStream, OutputStream outStream,

                     MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            mechCtxt.wrap(inStream, outStream, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public byte [] unwrap(byte[] inBuf, int offset, int len,

                          MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            return mechCtxt.unwrap(inBuf, offset, len, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public void unwrap(InputStream inStream, OutputStream outStream,

                       MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            mechCtxt.unwrap(inStream, outStream, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public byte[] getMIC(byte []inMsg, int offset, int len,

                         MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            return mechCtxt.getMIC(inMsg, offset, len, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public void getMIC(InputStream inStream, OutputStream outStream,

                       MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            mechCtxt.getMIC(inStream, outStream, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public void verifyMIC(byte[] inTok, int tokOffset, int tokLen,

                          byte[] inMsg, int msgOffset, int msgLen,

                          MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            mechCtxt.verifyMIC(inTok, tokOffset, tokLen,

                               inMsg, msgOffset, msgLen, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public void verifyMIC(InputStream tokStream, InputStream msgStream,

                          MessageProp msgProp) throws GSSException {

        if (mechCtxt != null)

            mechCtxt.verifyMIC(tokStream, msgStream, msgProp);

        else

            throw new GSSExceptionImpl(GSSException.NO_CONTEXT,

                                  "No mechanism context yet!");

    }

    public byte[] export() throws GSSException {

        // Defaults to null to match old behavior

        byte[] result = null;

        // Only allow context export from native provider since JGSS

        // still has not defined its own interprocess token format

        if (mechCtxt.isTransferable() &&

            mechCtxt.getProvider().getName().equals("SunNativeGSS")) {

            result = mechCtxt.export();

        }

        return result;

    }

    public void requestMutualAuth(boolean state) throws GSSException {

            reqMutualAuthState = state;

    }

    public void requestReplayDet(boolean state) throws GSSException {

            reqReplayDetState = state;

    }

    public void requestSequenceDet(boolean state) throws GSSException {

            reqSequenceDetState = state;

    }

    public void requestCredDeleg(boolean state) throws GSSException {

            reqCredDelegState = state;

    }

    public void requestAnonymity(boolean state) throws GSSException {

            reqAnonState = state;

    }

    public void requestConf(boolean state) throws GSSException {

            reqConfState = state;

    }

    public void requestInteg(boolean state) throws GSSException {

            reqIntegState = state;

    }

    public void requestLifetime(int lifetime) throws GSSException {

            reqLifetime = lifetime;

    }

    public void setChannelBinding(ChannelBinding channelBindings)

        throws GSSException {

        if (mechCtxt == null)

            this.channelBindings = channelBindings;

    }

    public boolean getCredDelegState() {

        if (mechCtxt != null)

            return mechCtxt.getCredDelegState();

        else

            return reqCredDelegState;

    }

    public boolean getMutualAuthState() {

        if (mechCtxt != null)

            return mechCtxt.getMutualAuthState();