kerberos-shared/src/main/java/org/apache/directory/server/kerberos/shared/io/decoder/EncTicketPartDecoder.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *  
 *    http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License. 
 *  
 */
package org.apache.directory.server.kerberos.shared.io.decoder;


import java.io.IOException;
import java.text.ParseException;
import java.util.Enumeration;

import org.apache.directory.server.kerberos.shared.messages.Encodable;
import org.apache.directory.server.kerberos.shared.messages.components.EncTicketPart;
import org.apache.directory.server.kerberos.shared.messages.value.TransitedEncoding;
import org.apache.directory.server.kerberos.shared.messages.value.flags.TicketFlags;
import org.apache.directory.server.kerberos.shared.messages.value.types.TransitedEncodingType;
import org.apache.directory.shared.asn1.der.ASN1InputStream;
import org.apache.directory.shared.asn1.der.DERApplicationSpecific;
import org.apache.directory.shared.asn1.der.DERBitString;
import org.apache.directory.shared.asn1.der.DEREncodable;
import org.apache.directory.shared.asn1.der.DERGeneralString;
import org.apache.directory.shared.asn1.der.DERGeneralizedTime;
import org.apache.directory.shared.asn1.der.DERInteger;
import org.apache.directory.shared.asn1.der.DEROctetString;
import org.apache.directory.shared.asn1.der.DERSequence;
import org.apache.directory.shared.asn1.der.DERTaggedObject;


/**
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 * @version $Rev$, $Date$
 */
public class EncTicketPartDecoder implements Decoder, DecoderFactory
{
    public Decoder getDecoder()
    {
        return new EncTicketPartDecoder();
    }


    public Encodable decode( byte[] encodedTicket ) throws IOException
    {
        ASN1InputStream ais = new ASN1InputStream( encodedTicket );

        DERApplicationSpecific app = ( DERApplicationSpecific ) ais.readObject();

        DERSequence sequence = ( DERSequence ) app.getObject();

        return decodeEncTicketPartSequence( sequence );
    }


    /*
     -- Encrypted part of ticket
     EncTicketPart ::=     [APPLICATION 3] SEQUENCE {
     flags[0]             TicketFlags,
     key[1]               EncryptionKey,
     crealm[2]            Realm,
     cname[3]             PrincipalName,
     transited[4]         TransitedEncoding,
     authtime[5]          KerberosTime,
     starttime[6]         KerberosTime OPTIONAL,
     endtime[7]           KerberosTime,
     renew-till[8]        KerberosTime OPTIONAL,
     caddr[9]             HostAddresses OPTIONAL,
     authorization-data[10]   AuthorizationData OPTIONAL
     }*/
    private EncTicketPart decodeEncTicketPartSequence( DERSequence sequence )
    {
        EncTicketPart ticketPart = new EncTicketPart();

        for ( Enumeration e = sequence.getObjects(); e.hasMoreElements(); )
        {
            DERTaggedObject object = ( DERTaggedObject ) e.nextElement();
            int tag = object.getTagNo();
            DEREncodable derObject = object.getObject();

            switch ( tag )
            {
                case 0:
                    DERBitString tag0 = ( DERBitString ) derObject;
                    ticketPart.setFlags( new TicketFlags( tag0.getOctets() ) );
                    break;
                    
                case 1:
                    DERSequence tag1 = ( DERSequence ) derObject;
                    ticketPart.setSessionKey( EncryptionKeyDecoder.decode( tag1 ) );
                    break;
                    
                case 2:
                    DERGeneralString tag2 = ( DERGeneralString ) derObject;
                    ticketPart.setClientRealm( tag2.getString() );
                    break;
                    
                case 3:
                    DERSequence tag3 = ( DERSequence ) derObject;
                    
                    try
                    {
                        ticketPart.setClientPrincipalName( PrincipalNameDecoder.decode( tag3 ) );
                    }
                    catch ( ParseException pe )
                    {
                        // Do nothing
                    }
                    
                    break;
                    
                case 4:
                    DERSequence tag4 = ( DERSequence ) derObject;
                    ticketPart.setTransitedEncoding( decodeTransitedEncoding( tag4 ) );
                    break;
                    
                case 5:
                    DERGeneralizedTime tag5 = ( DERGeneralizedTime ) derObject;
                    ticketPart.setAuthTime( KerberosTimeDecoder.decode( tag5 ) );
                    break;
                    
                case 6:
                    DERGeneralizedTime tag6 = ( DERGeneralizedTime ) derObject;
                    ticketPart.setStartTime( KerberosTimeDecoder.decode( tag6 ) );
                    break;
                    
                case 7:
                    DERGeneralizedTime tag7 = ( DERGeneralizedTime ) derObject;
                    ticketPart.setEndTime( KerberosTimeDecoder.decode( tag7 ) );
                    break;
                    
                case 8:
                    DERGeneralizedTime tag8 = ( DERGeneralizedTime ) derObject;
                    ticketPart.setRenewTill( KerberosTimeDecoder.decode( tag8 ) );
                    break;
                    
                case 9:
                    DERSequence tag9 = ( DERSequence ) derObject;
                    ticketPart.setClientAddresses( HostAddressDecoder.decodeSequence( tag9 ) );
                    break;
                    
                case 10:
                    DERSequence tag10 = ( DERSequence ) derObject;
                    ticketPart.setAuthorizationData( AuthorizationDataDecoder.decodeSequence( tag10 ) );
                    break;
            }
        }
        
        return ticketPart;
    }


    /*
     * TransitedEncoding ::= SEQUENCE {
     *   tr-type[0] INTEGER, -- must be
     *   registered contents[1] OCTET STRING
     * }
     */
    protected TransitedEncoding decodeTransitedEncoding( DERSequence sequence )
    {
        TransitedEncodingType type = TransitedEncodingType.NULL;
        byte[] contents = null;

        for ( Enumeration e = sequence.getObjects(); e.hasMoreElements(); )
        {
            DERTaggedObject object = ( DERTaggedObject ) e.nextElement();
            int tag = object.getTagNo();
            DEREncodable derObject = object.getObject();

            switch ( tag )
            {
                case 0:
                    DERInteger tag0 = ( DERInteger ) derObject;
                    type = TransitedEncodingType.getTypeByOrdinal( tag0.intValue() );
                    break;
                case 1:
                    DEROctetString tag1 = ( DEROctetString ) derObject;
                    contents = tag1.getOctets();
                    break;
            }
        }

        return new TransitedEncoding( type, contents );
    }
}