/*

 * Copyright (c) 2005, 2009, 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.net.www.protocol.http.spnego;

import com.sun.security.jgss.ExtendedGSSContext;

import java.io.IOException;

import org.ietf.jgss.GSSContext;

import org.ietf.jgss.GSSException;

import org.ietf.jgss.GSSName;

import org.ietf.jgss.Oid;

import sun.net.www.protocol.http.HttpCallerInfo;

import sun.net.www.protocol.http.Negotiator;

import sun.security.jgss.GSSManagerImpl;

import sun.security.jgss.GSSUtil;

import sun.security.jgss.HttpCaller;

/**

 * This class encapsulates all JAAS and JGSS API calls in a separate class

 * outside NegotiateAuthentication.java so that J2SE build can go smoothly

 * without the presence of it.

 *

 * @author weijun.wang@sun.com

 * @since 1.6

 */

public class NegotiatorImpl extends Negotiator {

    private static final boolean DEBUG =

        java.security.AccessController.doPrivileged(

              new sun.security.action.GetBooleanAction("sun.security.krb5.debug"));

    private GSSContext context;

    private byte[] oneToken;

    /**

     * Initialize the object, which includes:<ul>

     * <li>Find out what GSS mechanism to use from the system property

     * <code>http.negotiate.mechanism.oid</code>, defaults SPNEGO

     * <li>Creating the GSSName for the target host, "HTTP/"+hostname

     * <li>Creating GSSContext

     * <li>A first call to initSecContext</ul>

     */

    private void init(HttpCallerInfo hci) throws GSSException {

        final Oid oid;

        if (hci.scheme.equalsIgnoreCase("Kerberos")) {

            // we can only use Kerberos mech when the scheme is kerberos

            oid = GSSUtil.GSS_KRB5_MECH_OID;

        } else {

            String pref = java.security.AccessController.doPrivileged(

                    new java.security.PrivilegedAction<String>() {

                        public String run() {

                            return System.getProperty(

                                "http.auth.preference",

                                "spnego");

                        }

                    });

            if (pref.equalsIgnoreCase("kerberos")) {

                oid = GSSUtil.GSS_KRB5_MECH_OID;

            } else {

                // currently there is no 3rd mech we can use

                oid = GSSUtil.GSS_SPNEGO_MECH_OID;

            }

        }

        GSSManagerImpl manager = new GSSManagerImpl(

                new HttpCaller(hci));

        // RFC 4559 4.1 uses uppercase service name "HTTP".

        // RFC 4120 6.2.1 demands the host be lowercase

        String peerName = "HTTP@" + hci.host.toLowerCase();

        GSSName serverName = manager.createName(peerName,

                GSSName.NT_HOSTBASED_SERVICE);

        context = manager.createContext(serverName,

                                        oid,

                                        null,

                                        GSSContext.DEFAULT_LIFETIME);

        // Always respect delegation policy in HTTP/SPNEGO.

        if (context instanceof ExtendedGSSContext) {

            ((ExtendedGSSContext)context).requestDelegPolicy(true);

        }

        oneToken = context.initSecContext(new byte[0], 0, 0);

    }

    /**

     * Constructor

     * @throws java.io.IOException If negotiator cannot be constructed

     */

    public NegotiatorImpl(HttpCallerInfo hci) throws IOException {

        try {

            init(hci);

        } catch (GSSException e) {

            if (DEBUG) {

                System.out.println("Negotiate support not initiated, will " +

                        "fallback to other scheme if allowed. Reason:");

                e.printStackTrace();

            }

            IOException ioe = new IOException("Negotiate support not initiated");

            ioe.initCause(e);

            throw ioe;

        }

    }

    /**

     * Return the first token of GSS, in SPNEGO, it's called NegTokenInit

     * @return the first token

     */

    @Override

    public byte[] firstToken() {

        return oneToken;

    }

    /**

     * Return the rest tokens of GSS, in SPNEGO, it's called NegTokenTarg

     * @param token the token received from server

     * @return the next token

     * @throws java.io.IOException if the token cannot be created successfully

     */

    @Override

    public byte[] nextToken(byte[] token) throws IOException {

        try {

            return context.initSecContext(token, 0, token.length);

        } catch (GSSException e) {

            if (DEBUG) {

                System.out.println("Negotiate support cannot continue. Reason:");

                e.printStackTrace();

            }

            IOException ioe = new IOException("Negotiate support cannot continue");

            ioe.initCause(e);

            throw ioe;

        }

    }

}