/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

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/*

 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

 */

package sun.security.krb5.internal;

import sun.security.krb5.*;

import sun.security.util.*;

import java.util.Vector;

import java.io.IOException;

import java.math.BigInteger;

/**

 * Implements the ASN.1 Authenticator type.

 *

 * <pre>{@code

 * Authenticator   ::= [APPLICATION 2] SEQUENCE  {

 *         authenticator-vno       [0] INTEGER (5),

 *         crealm                  [1] Realm,

 *         cname                   [2] PrincipalName,

 *         cksum                   [3] Checksum OPTIONAL,

 *         cusec                   [4] Microseconds,

 *         ctime                   [5] KerberosTime,

 *         subkey                  [6] EncryptionKey OPTIONAL,

 *         seq-number              [7] UInt32 OPTIONAL,

 *         authorization-data      [8] AuthorizationData OPTIONAL

 * }

 * }</pre>

 *

 * <p>

 * This definition reflects the Network Working Group RFC 4120

 * specification available at

 * <a href="http://www.ietf.org/rfc/rfc4120.txt">

 * http://www.ietf.org/rfc/rfc4120.txt</a>.

 */

public class Authenticator {

    public int authenticator_vno;

    public PrincipalName cname;

    Checksum cksum; //optional

    public int cusec;

    public KerberosTime ctime;

    EncryptionKey subKey; //optional

    Integer seqNumber; //optional

    public AuthorizationData authorizationData; //optional

    public Authenticator(

            PrincipalName new_cname,

            Checksum new_cksum,

            int new_cusec,

            KerberosTime new_ctime,

            EncryptionKey new_subKey,

            Integer new_seqNumber,

            AuthorizationData new_authorizationData) {

        authenticator_vno = Krb5.AUTHNETICATOR_VNO;

        cname = new_cname;

        cksum = new_cksum;

        cusec = new_cusec;

        ctime = new_ctime;

        subKey = new_subKey;

        seqNumber = new_seqNumber;

        authorizationData = new_authorizationData;

    }

    public Authenticator(byte[] data)

            throws Asn1Exception, IOException, KrbApErrException, RealmException {

        init(new DerValue(data));

    }

    public Authenticator(DerValue encoding)

            throws Asn1Exception, IOException, KrbApErrException, RealmException {

        init(encoding);

    }

    /**

     * Initializes an Authenticator object.

     * @param encoding a single DER-encoded value.

     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded data.

     * @exception KrbApErrException if the value read from the DER-encoded data

     *  stream does not match the pre-defined value.

     * @exception RealmException if an error occurs while parsing a Realm object.

     */

    private void init(DerValue encoding)

            throws Asn1Exception, IOException, KrbApErrException, RealmException {

        DerValue der, subDer;

        //may not be the correct error code for a tag

        //mismatch on an encrypted structure

        if (((encoding.getTag() & (byte) 0x1F) != (byte) 0x02)

                || (encoding.isApplication() != true)

                || (encoding.isConstructed() != true)) {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        der = encoding.getData().getDerValue();

        if (der.getTag() != DerValue.tag_Sequence) {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        subDer = der.getData().getDerValue();

        if ((subDer.getTag() & (byte) 0x1F) != (byte) 0x00) {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        authenticator_vno = subDer.getData().getBigInteger().intValue();

        if (authenticator_vno != 5) {

            throw new KrbApErrException(Krb5.KRB_AP_ERR_BADVERSION);

        }

        Realm crealm = Realm.parse(der.getData(), (byte) 0x01, false);

        cname = PrincipalName.parse(der.getData(), (byte) 0x02, false, crealm);

        cksum = Checksum.parse(der.getData(), (byte) 0x03, true);

        subDer = der.getData().getDerValue();

        if ((subDer.getTag() & (byte) 0x1F) == 0x04) {

            cusec = subDer.getData().getBigInteger().intValue();

        } else {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        ctime = KerberosTime.parse(der.getData(), (byte) 0x05, false);

        if (der.getData().available() > 0) {

            subKey = EncryptionKey.parse(der.getData(), (byte) 0x06, true);

        } else {

            subKey = null;

            seqNumber = null;

            authorizationData = null;

        }

        if (der.getData().available() > 0) {

            if ((der.getData().peekByte() & 0x1F) == 0x07) {

                subDer = der.getData().getDerValue();

                if ((subDer.getTag() & (byte) 0x1F) == (byte) 0x07) {

                    seqNumber = subDer.getData().getBigInteger().intValue();

                }

            }

        } else {

            seqNumber = null;

            authorizationData = null;

        }

        if (der.getData().available() > 0) {

            authorizationData = AuthorizationData.parse(der.getData(), (byte) 0x08, true);

        } else {

            authorizationData = null;

        }

        if (der.getData().available() > 0) {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

    }

    /**

     * Encodes an Authenticator object.

     * @return byte array of encoded Authenticator object.

     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded data.

     */

    public byte[] asn1Encode() throws Asn1Exception, IOException {

        Vector<DerValue> v = new Vector<>();

        DerOutputStream temp = new DerOutputStream();

        temp.putInteger(BigInteger.valueOf(authenticator_vno));

        v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x00), temp.toByteArray()));

        v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x01), cname.getRealm().asn1Encode()));

        v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x02), cname.asn1Encode()));

        if (cksum != null) {

            v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x03), cksum.asn1Encode()));

        }

        temp = new DerOutputStream();

        temp.putInteger(BigInteger.valueOf(cusec));

        v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x04), temp.toByteArray()));

        v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x05), ctime.asn1Encode()));

        if (subKey != null) {

            v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x06), subKey.asn1Encode()));

        }

        if (seqNumber != null) {

            temp = new DerOutputStream();

            // encode as an unsigned integer (UInt32)

            temp.putInteger(BigInteger.valueOf(seqNumber.longValue()));

            v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x07), temp.toByteArray()));

        }

        if (authorizationData != null) {

            v.addElement(new DerValue(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte) 0x08), authorizationData.asn1Encode()));

        }

        DerValue[] der = new DerValue[v.size()];

        v.copyInto(der);

        temp = new DerOutputStream();

        temp.putSequence(der);

        DerOutputStream out = new DerOutputStream();

        out.write(DerValue.createTag(DerValue.TAG_APPLICATION, true, (byte) 0x02), temp);

        return out.toByteArray();

    }

    public final Checksum getChecksum() {

        return cksum;

    }

    public final Integer getSeqNumber() {

        return seqNumber;

    }

    public final EncryptionKey getSubKey() {

        return subKey;

    }

}