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Java example source code file (KrbApReq.java)

This example Java source code file (KrbApReq.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

asn1exception, authorizationdata, checksum, credentials, debug, encryptionkey, ioexception, kerberostime, krbapreq, krbcryptoexception, krbexception, net, network, principalname, security, seqnumber, string, util

The KrbApReq.java Java example source code

/*
 * Copyright (c) 2000, 2013, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 *
 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.
 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.
 */

package sun.security.krb5;

import sun.security.krb5.internal.*;
import sun.security.krb5.internal.crypto.*;
import sun.security.jgss.krb5.Krb5AcceptCredential;
import java.net.InetAddress;
import sun.security.util.*;
import java.io.IOException;
import java.util.Arrays;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import sun.security.krb5.internal.rcache.AuthTimeWithHash;

/**
 * This class encapsulates a KRB-AP-REQ that a client sends to a
 * server for authentication.
 */
public class KrbApReq {

    private byte[] obuf;
    private KerberosTime ctime;
    private int cusec;
    private Authenticator authenticator;
    private Credentials creds;
    private APReq apReqMessg;

    // Used by acceptor side
    private static ReplayCache rcache = ReplayCache.getInstance();
    private static boolean DEBUG = Krb5.DEBUG;
    private static final char[] hexConst = "0123456789ABCDEF".toCharArray();

    private static final MessageDigest md;

    static {
        try {
            md = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException ex) {
            throw new RuntimeException("Impossible");
        }
    }

    /**
     * Constructs an AP-REQ message to send to the peer.
     * @param tgsCred the <code>Credentials to be used to construct the
     *          AP Request  protocol message.
     * @param mutualRequired Whether mutual authentication is required
     * @param useSubkey Whether the subkey is to be used to protect this
     *        specific application session. If this is not set then the
     *        session key from the ticket will be used.
     * @throws KrbException for any Kerberos protocol specific error
     * @throws IOException for any IO related errors
     *          (e.g. socket operations)
     */
     /*
     // Not Used
    public KrbApReq(Credentials tgsCred,
                    boolean mutualRequired,
                    boolean useSubKey,
                    boolean useSeqNumber) throws Asn1Exception,
                    KrbCryptoException, KrbException, IOException {

        this(tgsCred, mutualRequired, useSubKey, useSeqNumber, null);
    }
*/

    /**
     * Constructs an AP-REQ message to send to the peer.
     * @param tgsCred the <code>Credentials to be used to construct the
     *          AP Request  protocol message.
     * @param mutualRequired Whether mutual authentication is required
     * @param useSubkey Whether the subkey is to be used to protect this
     *        specific application session. If this is not set then the
     *        session key from the ticket will be used.
     * @param checksum checksum of the the application data that accompanies
     *        the KRB_AP_REQ.
     * @throws KrbException for any Kerberos protocol specific error
     * @throws IOException for any IO related errors
     *          (e.g. socket operations)
     */
     // Used in InitSecContextToken
    public KrbApReq(Credentials tgsCred,
                    boolean mutualRequired,
                    boolean useSubKey,
                    boolean useSeqNumber,
                    Checksum cksum) throws Asn1Exception,
                    KrbCryptoException, KrbException, IOException  {

        APOptions apOptions = (mutualRequired?
                               new APOptions(Krb5.AP_OPTS_MUTUAL_REQUIRED):
                               new APOptions());
        if (DEBUG)
            System.out.println(">>> KrbApReq: APOptions are " + apOptions);

        EncryptionKey subKey = (useSubKey?
                                new EncryptionKey(tgsCred.getSessionKey()):
                                null);

        SeqNumber seqNum = new LocalSeqNumber();

        init(apOptions,
             tgsCred,
             cksum,
             subKey,
             seqNum,
             null,   // AuthorizationData authzData
            KeyUsage.KU_AP_REQ_AUTHENTICATOR);

    }

    /**
     * Constructs an AP-REQ message from the bytes received from the
     * peer.
     * @param message The message received from the peer
     * @param keys <code>EncrtyptionKeys to decrypt the message;
     *       key selected will depend on etype used to encrypte data
     * @throws KrbException for any Kerberos protocol specific error
     * @throws IOException for any IO related errors
     *          (e.g. socket operations)
     */
     // Used in InitSecContextToken (for AP_REQ and not TGS REQ)
    public KrbApReq(byte[] message,
                    Krb5AcceptCredential cred,
                    InetAddress initiator)
        throws KrbException, IOException {
        obuf = message;
        if (apReqMessg == null)
            decode();
        authenticate(cred, initiator);
    }

    /**
     * Constructs an AP-REQ message from the bytes received from the
     * peer.
     * @param value The <code>DerValue that contains the
     *              DER enoded AP-REQ protocol message
     * @param keys <code>EncrtyptionKeys to decrypt the message;
     *
     * @throws KrbException for any Kerberos protocol specific error
     * @throws IOException for any IO related errors
     *          (e.g. socket operations)
     */
     /*
    public KrbApReq(DerValue value, EncryptionKey[] key, InetAddress initiator)
        throws KrbException, IOException {
        obuf = value.toByteArray();
        if (apReqMessg == null)
            decode(value);
        authenticate(keys, initiator);
    }

    KrbApReq(APOptions options,
             Credentials tgs_creds,
             Checksum cksum,
             EncryptionKey subKey,
             SeqNumber seqNumber,
             AuthorizationData authorizationData)
        throws KrbException, IOException {
        init(options, tgs_creds, cksum, subKey, seqNumber, authorizationData);
    }
*/

     /** used by KrbTgsReq **/
    KrbApReq(APOptions apOptions,
             Ticket ticket,
             EncryptionKey key,
             PrincipalName cname,
             Checksum cksum,
             KerberosTime ctime,
             EncryptionKey subKey,
             SeqNumber seqNumber,
        AuthorizationData authorizationData)
        throws Asn1Exception, IOException,
               KdcErrException, KrbCryptoException {

        init(apOptions, ticket, key, cname,
             cksum, ctime, subKey, seqNumber, authorizationData,
            KeyUsage.KU_PA_TGS_REQ_AUTHENTICATOR);

    }

    private void init(APOptions options,
                      Credentials tgs_creds,
                      Checksum cksum,
                      EncryptionKey subKey,
                      SeqNumber seqNumber,
                      AuthorizationData authorizationData,
        int usage)
        throws KrbException, IOException {

        ctime = KerberosTime.now();
        init(options,
             tgs_creds.ticket,
             tgs_creds.key,
             tgs_creds.client,
             cksum,
             ctime,
             subKey,
             seqNumber,
             authorizationData,
            usage);
    }

    private void init(APOptions apOptions,
                      Ticket ticket,
                      EncryptionKey key,
                      PrincipalName cname,
                      Checksum cksum,
                      KerberosTime ctime,
                      EncryptionKey subKey,
                      SeqNumber seqNumber,
                      AuthorizationData authorizationData,
        int usage)
        throws Asn1Exception, IOException,
               KdcErrException, KrbCryptoException {

        createMessage(apOptions, ticket, key, cname,
                      cksum, ctime, subKey, seqNumber, authorizationData,
            usage);
        obuf = apReqMessg.asn1Encode();
    }


    void decode() throws KrbException, IOException {
        DerValue encoding = new DerValue(obuf);
        decode(encoding);
    }

    void decode(DerValue encoding) throws KrbException, IOException {
        apReqMessg = null;
        try {
            apReqMessg = new APReq(encoding);
        } catch (Asn1Exception e) {
            apReqMessg = null;
            KRBError err = new KRBError(encoding);
            String errStr = err.getErrorString();
            String eText;
            if (errStr.charAt(errStr.length() - 1) == 0)
                eText = errStr.substring(0, errStr.length() - 1);
            else
                eText = errStr;
            KrbException ke = new KrbException(err.getErrorCode(), eText);
            ke.initCause(e);
            throw ke;
        }
    }

    private void authenticate(Krb5AcceptCredential cred, InetAddress initiator)
        throws KrbException, IOException {
        int encPartKeyType = apReqMessg.ticket.encPart.getEType();
        Integer kvno = apReqMessg.ticket.encPart.getKeyVersionNumber();
        EncryptionKey[] keys = cred.getKrb5EncryptionKeys(apReqMessg.ticket.sname);
        EncryptionKey dkey = EncryptionKey.findKey(encPartKeyType, kvno, keys);

        if (dkey == null) {
            throw new KrbException(Krb5.API_INVALID_ARG,
                "Cannot find key of appropriate type to decrypt AP REP - " +
                                   EType.toString(encPartKeyType));
        }

        byte[] bytes = apReqMessg.ticket.encPart.decrypt(dkey,
            KeyUsage.KU_TICKET);
        byte[] temp = apReqMessg.ticket.encPart.reset(bytes);
        EncTicketPart enc_ticketPart = new EncTicketPart(temp);

        checkPermittedEType(enc_ticketPart.key.getEType());

        byte[] bytes2 = apReqMessg.authenticator.decrypt(enc_ticketPart.key,
            KeyUsage.KU_AP_REQ_AUTHENTICATOR);
        byte[] temp2 = apReqMessg.authenticator.reset(bytes2);
        authenticator = new Authenticator(temp2);
        ctime = authenticator.ctime;
        cusec = authenticator.cusec;
        authenticator.ctime =
                authenticator.ctime.withMicroSeconds(authenticator.cusec);

        if (!authenticator.cname.equals(enc_ticketPart.cname)) {
            throw new KrbApErrException(Krb5.KRB_AP_ERR_BADMATCH);
        }

        if (!authenticator.ctime.inClockSkew())
            throw new KrbApErrException(Krb5.KRB_AP_ERR_SKEW);

        byte[] hash = md.digest(apReqMessg.authenticator.cipher);
        char[] h = new char[hash.length * 2];
        for (int i=0; i<hash.length; i++) {
            h[2*i] = hexConst[(hash[i]&0xff)>>4];
            h[2*i+1] = hexConst[hash[i]&0xf];
        }
        AuthTimeWithHash time = new AuthTimeWithHash(
                authenticator.cname.toString(),
                apReqMessg.ticket.sname.toString(),
                authenticator.ctime.getSeconds(),
                authenticator.cusec,
                new String(h));
        rcache.checkAndStore(KerberosTime.now(), time);

        if (initiator != null) {
            // sender host address
            HostAddress sender = new HostAddress(initiator);
            if (enc_ticketPart.caddr != null
                    && !enc_ticketPart.caddr.inList(sender)) {
                if (DEBUG) {
                    System.out.println(">>> KrbApReq: initiator is "
                            + sender.getInetAddress()
                            + ", but caddr is "
                            + Arrays.toString(
                                enc_ticketPart.caddr.getInetAddresses()));
                }
                throw new KrbApErrException(Krb5.KRB_AP_ERR_BADADDR);
            }
        }

        // XXX check for repeated authenticator
        // if found
        //    throw new KrbApErrException(Krb5.KRB_AP_ERR_REPEAT);
        // else
        //    save authenticator to check for later

        KerberosTime now = KerberosTime.now();

        if ((enc_ticketPart.starttime != null &&
             enc_ticketPart.starttime.greaterThanWRTClockSkew(now)) ||
            enc_ticketPart.flags.get(Krb5.TKT_OPTS_INVALID))
            throw new KrbApErrException(Krb5.KRB_AP_ERR_TKT_NYV);

        // if the current time is later than end time by more
        // than the allowable clock skew, throws ticket expired exception.
        if (enc_ticketPart.endtime != null &&
            now.greaterThanWRTClockSkew(enc_ticketPart.endtime)) {
            throw new KrbApErrException(Krb5.KRB_AP_ERR_TKT_EXPIRED);
        }

        creds = new Credentials(
                                apReqMessg.ticket,
                                authenticator.cname,
                                apReqMessg.ticket.sname,
                                enc_ticketPart.key,
                                enc_ticketPart.flags,
                                enc_ticketPart.authtime,
                                enc_ticketPart.starttime,
                                enc_ticketPart.endtime,
                                enc_ticketPart.renewTill,
                                enc_ticketPart.caddr,
                                enc_ticketPart.authorizationData);
        if (DEBUG) {
            System.out.println(">>> KrbApReq: authenticate succeed.");
        }
    }

    /**
     * Returns the credentials that are contained in the ticket that
     * is part of this this AP-REP.
     */
    public Credentials getCreds() {
        return creds;
    }

    KerberosTime getCtime() {
        if (ctime != null)
            return ctime;
        return authenticator.ctime;
    }

    int cusec() {
        return cusec;
    }

    APOptions getAPOptions() throws KrbException, IOException {
        if (apReqMessg == null)
            decode();
        if (apReqMessg != null)
            return apReqMessg.apOptions;
        return null;
    }

    /**
     * Returns true if mutual authentication is required and hence an
     * AP-REP will need to be generated.
     * @throws KrbException
     * @throws IOException
     */
    public boolean getMutualAuthRequired() throws KrbException, IOException {
        if (apReqMessg == null)
            decode();
        if (apReqMessg != null)
            return apReqMessg.apOptions.get(Krb5.AP_OPTS_MUTUAL_REQUIRED);
        return false;
    }

    boolean useSessionKey() throws KrbException, IOException {
        if (apReqMessg == null)
            decode();
        if (apReqMessg != null)
            return apReqMessg.apOptions.get(Krb5.AP_OPTS_USE_SESSION_KEY);
        return false;
    }

    /**
     * Returns the optional subkey stored in the Authenticator for
     * this message. Returns null if none is stored.
     */
    public EncryptionKey getSubKey() {
        // XXX Can authenticator be null
        return authenticator.getSubKey();
    }

    /**
     * Returns the optional sequence number stored in the
     * Authenticator for this message. Returns null if none is
     * stored.
     */
    public Integer getSeqNumber() {
        // XXX Can authenticator be null
        return authenticator.getSeqNumber();
    }

    /**
     * Returns the optional Checksum stored in the
     * Authenticator for this message. Returns null if none is
     * stored.
     */
    public Checksum getChecksum() {
        return authenticator.getChecksum();
    }

    /**
     * Returns the ASN.1 encoding that should be sent to the peer.
     */
    public byte[] getMessage() {
        return obuf;
    }

    /**
     * Returns the principal name of the client that generated this
     * message.
     */
    public PrincipalName getClient() {
        return creds.getClient();
    }

    private void createMessage(APOptions apOptions,
                               Ticket ticket,
                               EncryptionKey key,
                               PrincipalName cname,
                               Checksum cksum,
                               KerberosTime ctime,
                               EncryptionKey subKey,
                               SeqNumber seqNumber,
                               AuthorizationData authorizationData,
        int usage)
        throws Asn1Exception, IOException,
               KdcErrException, KrbCryptoException {

        Integer seqno = null;

        if (seqNumber != null)
            seqno = new Integer(seqNumber.current());

        authenticator =
            new Authenticator(cname,
                              cksum,
                              ctime.getMicroSeconds(),
                              ctime,
                              subKey,
                              seqno,
                              authorizationData);

        byte[] temp = authenticator.asn1Encode();

        EncryptedData encAuthenticator =
            new EncryptedData(key, temp, usage);

        apReqMessg =
            new APReq(apOptions, ticket, encAuthenticator);
    }

     // Check that key is one of the permitted types
     private static void checkPermittedEType(int target) throws KrbException {
        int[] etypes = EType.getDefaults("permitted_enctypes");
        if (!EType.isSupported(target, etypes)) {
            throw new KrbException(EType.toString(target) +
                " encryption type not in permitted_enctypes list");
        }
     }
}

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