/*

 * Copyright 2005-2009 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.spnego;

import org.ietf.jgss.*;

import sun.security.jgss.*;

import sun.security.jgss.spi.*;

import sun.security.jgss.krb5.Krb5MechFactory;

import sun.security.jgss.krb5.Krb5InitCredential;

import sun.security.jgss.krb5.Krb5AcceptCredential;

import sun.security.jgss.krb5.Krb5NameElement;

import java.security.Provider;

import java.util.Vector;

/**

 * SpNego Mechanism plug in for JGSS

 * This is the properties object required by the JGSS framework.

 * All mechanism specific information is defined here.

 *

 * @author Seema Malkani

 * @since 1.6

 */

public final class SpNegoMechFactory implements MechanismFactory {

    static final Provider PROVIDER =

        new sun.security.jgss.SunProvider();

    static final Oid GSS_SPNEGO_MECH_OID =

        GSSUtil.createOid("1.3.6.1.5.5.2");

    private static Oid[] nameTypes =

        new Oid[] { GSSName.NT_USER_NAME,

                        GSSName.NT_HOSTBASED_SERVICE,

                        GSSName.NT_EXPORT_NAME};

    // Use an instance of a GSSManager whose provider list

    // does not include native provider

    final GSSManagerImpl manager;

    final Oid[] availableMechs;

    private static SpNegoCredElement getCredFromSubject(GSSNameSpi name,

                                                        boolean initiate)

        throws GSSException {

        Vector<SpNegoCredElement> creds =

            GSSUtil.searchSubject(name, GSS_SPNEGO_MECH_OID,

                initiate, SpNegoCredElement.class);

        SpNegoCredElement result = ((creds == null || creds.isEmpty()) ?

                                    null : creds.firstElement());

        // Force permission check before returning the cred to caller

        if (result != null) {

            GSSCredentialSpi cred = result.getInternalCred();

            if (GSSUtil.isKerberosMech(cred.getMechanism())) {

                if (initiate) {

                    Krb5InitCredential krbCred = (Krb5InitCredential) cred;

                    Krb5MechFactory.checkInitCredPermission

                        ((Krb5NameElement) krbCred.getName());

                } else {

                    Krb5AcceptCredential krbCred = (Krb5AcceptCredential) cred;

                    Krb5MechFactory.checkAcceptCredPermission

                        ((Krb5NameElement) krbCred.getName(), name);

                }

            }

        }

        return result;

    }

    public SpNegoMechFactory(GSSCaller caller) {

        manager = new GSSManagerImpl(caller, false);

        Oid[] mechs = manager.getMechs();

        availableMechs = new Oid[mechs.length-1];

        for (int i = 0, j = 0; i < mechs.length; i++) {

            // Skip SpNego mechanism

            if (!mechs[i].equals(GSS_SPNEGO_MECH_OID)) {

                availableMechs[j++] = mechs[i];

            }

        }

    }

    public GSSNameSpi getNameElement(String nameStr, Oid nameType)

        throws GSSException {

        // get NameElement for the default Mechanism

        return manager.getNameElement(nameStr, nameType, null);

    }

    public GSSNameSpi getNameElement(byte[] name, Oid nameType)

        throws GSSException {

        // get NameElement for the default Mechanism

        return manager.getNameElement(name, nameType, null);

    }

    public GSSCredentialSpi getCredentialElement(GSSNameSpi name,

           int initLifetime, int acceptLifetime,

           int usage) throws GSSException {

        SpNegoCredElement credElement = getCredFromSubject

            (name, (usage != GSSCredential.ACCEPT_ONLY));

        if (credElement == null) {

            // get CredElement for the default Mechanism

            credElement = new SpNegoCredElement

                (manager.getCredentialElement(name, initLifetime,

                acceptLifetime, null, usage));

        }

        return credElement;

    }

    public GSSContextSpi getMechanismContext(GSSNameSpi peer,

                             GSSCredentialSpi myInitiatorCred, int lifetime)

        throws GSSException {

        // get SpNego mechanism context

        if (myInitiatorCred == null) {

            myInitiatorCred = getCredFromSubject(null, true);

        } else if (!(myInitiatorCred instanceof SpNegoCredElement)) {

            // convert to SpNegoCredElement

            SpNegoCredElement cred = new SpNegoCredElement(myInitiatorCred);

            return new SpNegoContext(this, peer, cred, lifetime);

        }

        return new SpNegoContext(this, peer, myInitiatorCred, lifetime);

    }

    public GSSContextSpi getMechanismContext(GSSCredentialSpi myAcceptorCred)

        throws GSSException {

        // get SpNego mechanism context

        if (myAcceptorCred == null) {

            myAcceptorCred = getCredFromSubject(null, false);

        } else if (!(myAcceptorCred instanceof SpNegoCredElement)) {

            // convert to SpNegoCredElement

            SpNegoCredElement cred = new SpNegoCredElement(myAcceptorCred);

            return new SpNegoContext(this, cred);

        }

        return new SpNegoContext(this, myAcceptorCred);

    }

    public GSSContextSpi getMechanismContext(byte[] exportedContext)

        throws GSSException {

        // get SpNego mechanism context

        return new SpNegoContext(this, exportedContext);

    }

    public final Oid getMechanismOid() {

        return GSS_SPNEGO_MECH_OID;

    }

    public Provider getProvider() {

        return PROVIDER;

    }

    public Oid[] getNameTypes() {

        // nameTypes is cloned in GSSManager.getNamesForMech

        return nameTypes;

    }

}