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/*
 * Copyright (c) 2004, 2010, 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
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 *
 * 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,
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 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.security.jgss.krb5;

import org.ietf.jgss.*;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.security.MessageDigest;
import java.util.Arrays;


This class is a base class for new GSS token definitions, as defined
in RFC 4121, that pertain to per-message GSS-API calls. Conceptually
GSS-API has two types of per-message tokens: WrapToken and MicToken.
They differ in the respect that a WrapToken carries additional plaintext
or ciphertext application data besides just the sequence number and
checksum. This class encapsulates the commonality in the structure of
the WrapToken and the MicToken. This structure can be represented as:



Wrap Tokens
    Octet no   Name        Description
   ---------------------------------------------------------------
     0..1     TOK_ID     Identification field.  Tokens emitted by
                         GSS_Wrap() contain the hex value 05 04
                         expressed in big-endian order in this field.
     2        Flags      Attributes field, as described in section
                         4.2.2.
     3        Filler     Contains the hex value FF.
     4..5     EC         Contains the "extra count" field, in big-
                         endian order as described in section 4.2.3.
     6..7     RRC        Contains the "right rotation count" in big
                         endian order, as described in section 4.2.5.
     8..15    SND_SEQ    Sequence number field in clear text,
                         expressed in big-endian order.
     16..last Data       Encrypted data for Wrap tokens with
                         confidentiality, or plaintext data followed
                         by the checksum for Wrap tokens without
                         confidentiality, as described in section
                         4.2.4.
MIC Tokens
    Octet no   Name        Description
    -----------------------------------------------------------------
     0..1     TOK_ID     Identification field.  Tokens emitted by
                         GSS_GetMIC() contain the hex value 04 04
                         expressed in big-endian order in this field.
     2        Flags      Attributes field, as described in section
                         4.2.2.
     3..7     Filler     Contains five octets of hex value FF.
     8..15    SND_SEQ    Sequence number field in clear text,
                         expressed in big-endian order.
     16..last SGN_CKSUM  Checksum of the "to-be-signed" data and
                         octet 0..15, as described in section 4.2.4.




This class is the super class of WrapToken_v2 and MicToken_v2. The token's
header (bytes[0..15]) and data (byte[16..]) are saved in tokenHeader and
tokenData fields. Since there is no easy way to find out the exact length
of a WrapToken_v2 token from any header info, in the case of reading from
stream, we read all available() bytes into the token.


All read actions are performed in this super class. On the write part, the
super class only write the tokenHeader, and the content writing is inside
child classes.

Author:Seema Malkani
/**
 * This class is a base class for new GSS token definitions, as defined
 * in RFC 4121, that pertain to per-message GSS-API calls. Conceptually
 * GSS-API has two types of per-message tokens: WrapToken and MicToken.
 * They differ in the respect that a WrapToken carries additional plaintext
 * or ciphertext application data besides just the sequence number and
 * checksum. This class encapsulates the commonality in the structure of
 * the WrapToken and the MicToken. This structure can be represented as:
 * <p>
 * <pre>
 * Wrap Tokens
 *
 *     Octet no   Name        Description
 *    ---------------------------------------------------------------
 *      0..1     TOK_ID     Identification field.  Tokens emitted by
 *                          GSS_Wrap() contain the hex value 05 04
 *                          expressed in big-endian order in this field.
 *      2        Flags      Attributes field, as described in section
 *                          4.2.2.
 *      3        Filler     Contains the hex value FF.
 *      4..5     EC         Contains the "extra count" field, in big-
 *                          endian order as described in section 4.2.3.
 *      6..7     RRC        Contains the "right rotation count" in big
 *                          endian order, as described in section 4.2.5.
 *      8..15    SND_SEQ    Sequence number field in clear text,
 *                          expressed in big-endian order.
 *      16..last Data       Encrypted data for Wrap tokens with
 *                          confidentiality, or plaintext data followed
 *                          by the checksum for Wrap tokens without
 *                          confidentiality, as described in section
 *                          4.2.4.
 * MIC Tokens
 *
 *     Octet no   Name        Description
 *     -----------------------------------------------------------------
 *      0..1     TOK_ID     Identification field.  Tokens emitted by
 *                          GSS_GetMIC() contain the hex value 04 04
 *                          expressed in big-endian order in this field.
 *      2        Flags      Attributes field, as described in section
 *                          4.2.2.
 *      3..7     Filler     Contains five octets of hex value FF.
 *      8..15    SND_SEQ    Sequence number field in clear text,
 *                          expressed in big-endian order.
 *      16..last SGN_CKSUM  Checksum of the "to-be-signed" data and
 *                          octet 0..15, as described in section 4.2.4.
 *
 * </pre>
 * <p>
 * This class is the super class of WrapToken_v2 and MicToken_v2. The token's
 * header (bytes[0..15]) and data (byte[16..]) are saved in tokenHeader and
 * tokenData fields. Since there is no easy way to find out the exact length
 * of a WrapToken_v2 token from any header info, in the case of reading from
 * stream, we read all available() bytes into the token.
 * <p>
 * All read actions are performed in this super class. On the write part, the
 * super class only write the tokenHeader, and the content writing is inside
 * child classes.
 *
 * @author Seema Malkani
 */

abstract class MessageToken_v2 extends Krb5Token {

    protected static final int TOKEN_HEADER_SIZE = 16;
    private static final int TOKEN_ID_POS = 0;
    private static final int TOKEN_FLAG_POS = 2;
    private static final int TOKEN_EC_POS = 4;
    private static final int TOKEN_RRC_POS = 6;

    
The size of the random confounder used in a WrapToken.

/**
     * The size of the random confounder used in a WrapToken.
     */
    protected static final int CONFOUNDER_SIZE = 16;

    // RFC 4121, key usage values
    static final int KG_USAGE_ACCEPTOR_SEAL = 22;
    static final int KG_USAGE_ACCEPTOR_SIGN = 23;
    static final int KG_USAGE_INITIATOR_SEAL = 24;
    static final int KG_USAGE_INITIATOR_SIGN = 25;

    // RFC 4121, Flags Field
    private static final int FLAG_SENDER_IS_ACCEPTOR = 1;
    private static final int FLAG_WRAP_CONFIDENTIAL  = 2;
    private static final int FLAG_ACCEPTOR_SUBKEY    = 4;
    private static final int FILLER = 0xff;

    private MessageTokenHeader tokenHeader = null;

    // Common field
    private int tokenId = 0;
    private int seqNumber;
    protected byte[] tokenData; // content of token, without the header
    protected int tokenDataLen;

    // Key usage number for crypto action
    private int key_usage = 0;

    // EC and RRC fields, WrapToken only
    private int ec = 0;
    private int rrc = 0;

    // Checksum. Always in MicToken, might be in WrapToken
    byte[] checksum = null;

    // Context properties
    private boolean confState = true;
    private boolean initiator = true;

    /* cipher instance used by the corresponding GSSContext */
    CipherHelper cipherHelper = null;

    
Constructs a MessageToken from a byte array.

Params:
  • tokenId – the token id that should be contained in this token as
it is read.
  • context – the Kerberos context associated with this token
  • tokenBytes – the byte array containing the token
  • tokenOffset – the offset where the token begins
  • tokenLen – the length of the token
  • prop – the MessageProp structure in which the properties of the
token should be stored.
Throws:
/**
     * Constructs a MessageToken from a byte array.
     *
     * @param tokenId the token id that should be contained in this token as
     * it is read.
     * @param context the Kerberos context associated with this token
     * @param tokenBytes the byte array containing the token
     * @param tokenOffset the offset where the token begins
     * @param tokenLen the length of the token
     * @param prop the MessageProp structure in which the properties of the
     * token should be stored.
     * @throws GSSException if there is a problem parsing the token
     */
    MessageToken_v2(int tokenId, Krb5Context context,
                 byte[] tokenBytes, int tokenOffset, int tokenLen,
                 MessageProp prop) throws GSSException {
        this(tokenId, context,
             new ByteArrayInputStream(tokenBytes, tokenOffset, tokenLen),
             prop);
    }

    
Constructs a MessageToken from an InputStream. Bytes will be read on
demand and the thread might block if there are not enough bytes to
complete the token. Please note there is no accurate way to find out
the size of a token, but we try our best to make sure there is
enough bytes to construct one.

Params:
  • tokenId – the token id that should be contained in this token as
it is read.
  • context – the Kerberos context associated with this token
  • is – the InputStream from which to read
  • prop – the MessageProp structure in which the properties of the
token should be stored.
Throws:
  • GSSException – if there is a problem reading from the
InputStream or parsing the token
/**
     * Constructs a MessageToken from an InputStream. Bytes will be read on
     * demand and the thread might block if there are not enough bytes to
     * complete the token. Please note there is no accurate way to find out
     * the size of a token, but we try our best to make sure there is
     * enough bytes to construct one.
     *
     * @param tokenId the token id that should be contained in this token as
     * it is read.
     * @param context the Kerberos context associated with this token
     * @param is the InputStream from which to read
     * @param prop the MessageProp structure in which the properties of the
     * token should be stored.
     * @throws GSSException if there is a problem reading from the
     * InputStream or parsing the token
     */
    MessageToken_v2(int tokenId, Krb5Context context, InputStream is,
                 MessageProp prop) throws GSSException {
        init(tokenId, context);

        try {
            if (!confState) {
                prop.setPrivacy(false);
            }
            tokenHeader = new MessageTokenHeader(is, prop, tokenId);

            // set key_usage
            if (tokenId == Krb5Token.WRAP_ID_v2) {
                key_usage = (!initiator ? KG_USAGE_INITIATOR_SEAL
                                : KG_USAGE_ACCEPTOR_SEAL);
            } else if (tokenId == Krb5Token.MIC_ID_v2) {
                key_usage = (!initiator ? KG_USAGE_INITIATOR_SIGN
                                : KG_USAGE_ACCEPTOR_SIGN);
            }

            int minSize = 0;    // minimal size for token data
            if (tokenId == Krb5Token.WRAP_ID_v2 && prop.getPrivacy()) {
                minSize = CONFOUNDER_SIZE +
                        TOKEN_HEADER_SIZE + cipherHelper.getChecksumLength();
            } else {
                minSize = cipherHelper.getChecksumLength();
            }

            // Read token data
            if (tokenId == Krb5Token.MIC_ID_v2) {
                // The only case we can precisely predict the token data length
                tokenDataLen = minSize;
                tokenData = new byte[minSize];
                readFully(is, tokenData);
            } else {
                tokenDataLen = is.available();
                if (tokenDataLen >= minSize) {  // read in one shot
                    tokenData = new byte[tokenDataLen];
                    readFully(is, tokenData);
                } else {
                    byte[] tmp = new byte[minSize];
                    readFully(is, tmp);
                    // Hope while blocked in the read above, more data would
                    // come and is.available() below contains the whole token.
                    int more = is.available();
                    tokenDataLen = minSize + more;
                    tokenData = Arrays.copyOf(tmp, tokenDataLen);
                    readFully(is, tokenData, minSize, more);
                }
            }

            if (tokenId == Krb5Token.WRAP_ID_v2) {
                // Does non-confidential data needs a rotate?
                rotate();
            }

            if (tokenId == Krb5Token.MIC_ID_v2 ||
                    (tokenId == Krb5Token.WRAP_ID_v2 && !prop.getPrivacy())) {
                // Read checksum
                int chkLen = cipherHelper.getChecksumLength();
                checksum = new byte[chkLen];
                System.arraycopy(tokenData, tokenDataLen-chkLen,
                        checksum, 0, chkLen);

                // validate EC for Wrap tokens without confidentiality
                if (tokenId == Krb5Token.WRAP_ID_v2 && !prop.getPrivacy()) {
                    if (chkLen != ec) {
                        throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
                            getTokenName(tokenId) + ":" + "EC incorrect!");
                    }
                }
            }
        } catch (IOException e) {
            throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
                getTokenName(tokenId) + ":" + e.getMessage());
        }
    }

    
Used to obtain the token id that was contained in this token.

Returns:the token id in the token
/**
     * Used to obtain the token id that was contained in this token.
     * @return the token id in the token
     */
    public final int getTokenId() {
        return tokenId;
    }

    
Used to obtain the key_usage type for this token.

Returns:the key_usage for the token
/**
     * Used to obtain the key_usage type for this token.
     * @return the key_usage for the token
     */
    public final int getKeyUsage() {
        return key_usage;
    }

    
Used to determine if this token contains any encrypted data.

Returns:true if it contains any encrypted data, false if there is only
plaintext data or if there is no data.
/**
     * Used to determine if this token contains any encrypted data.
     * @return true if it contains any encrypted data, false if there is only
     * plaintext data or if there is no data.
     */
    public final boolean getConfState() {
        return confState;
    }

    
Generates the checksum field and the sequence number field.

Params:
  • prop – the MessageProp structure
  • data – the application data to checksum
  • offset – the offset where the data starts
  • len – the length of the data
Throws:
  • GSSException – if an error occurs in the checksum calculation or
sequence number calculation.
/**
     * Generates the checksum field and the sequence number field.
     *
     * @param prop the MessageProp structure
     * @param data the application data to checksum
     * @param offset the offset where the data starts
     * @param len the length of the data
     *
     * @throws GSSException if an error occurs in the checksum calculation or
     * sequence number calculation.
     */
    public void genSignAndSeqNumber(MessageProp prop,
                                    byte[] data, int offset, int len)
        throws GSSException {

        //    debug("Inside MessageToken.genSignAndSeqNumber:\n");

        int qop = prop.getQOP();
        if (qop != 0) {
            qop = 0;
            prop.setQOP(qop);
        }

        if (!confState) {
            prop.setPrivacy(false);
        }

        // Create a new gss token header as defined in RFC 4121
        tokenHeader = new MessageTokenHeader(tokenId,
                                prop.getPrivacy(), true);
        // debug("\n\t Message Header = " +
        // getHexBytes(tokenHeader.getBytes(), tokenHeader.getBytes().length));

        // set key_usage
        if (tokenId == Krb5Token.WRAP_ID_v2) {
            key_usage = (initiator ? KG_USAGE_INITIATOR_SEAL
                                : KG_USAGE_ACCEPTOR_SEAL);
        } else if (tokenId == Krb5Token.MIC_ID_v2) {
            key_usage = (initiator ? KG_USAGE_INITIATOR_SIGN
                                : KG_USAGE_ACCEPTOR_SIGN);
        }

        // Calculate SGN_CKSUM
        if ((tokenId == MIC_ID_v2) ||
            (!prop.getPrivacy() && (tokenId == WRAP_ID_v2))) {
           checksum = getChecksum(data, offset, len);
           // debug("\n\tCalc checksum=" +
           //  getHexBytes(checksum, checksum.length));
        }

        // In Wrap tokens without confidentiality, the EC field SHALL be used
        // to encode the number of octets in the trailing checksum
        if (!prop.getPrivacy() && (tokenId == WRAP_ID_v2)) {
            byte[] tok_header = tokenHeader.getBytes();
            tok_header[4] = (byte) (checksum.length >>> 8);
            tok_header[5] = (byte) (checksum.length);
        }
    }

    
Verifies the validity of checksum field

Params:
  • data – the application data
  • offset – the offset where the data begins
  • len – the length of the application data
Throws:
  • GSSException – if an error occurs in the checksum calculation
/**
     * Verifies the validity of checksum field
     *
     * @param data the application data
     * @param offset the offset where the data begins
     * @param len the length of the application data
     *
     * @throws GSSException if an error occurs in the checksum calculation
     */
    public final boolean verifySign(byte[] data, int offset, int len)
        throws GSSException {

        // debug("\t====In verifySign:====\n");
        // debug("\t\t checksum:   [" + getHexBytes(checksum) + "]\n");
        // debug("\t\t data = [" + getHexBytes(data) + "]\n");

        byte[] myChecksum = getChecksum(data, offset, len);
        // debug("\t\t mychecksum: [" + getHexBytes(myChecksum) +"]\n");

        if (MessageDigest.isEqual(checksum, myChecksum)) {
            // debug("\t\t====Checksum PASS:====\n");
            return true;
        }
        return false;
    }

    
Rotate bytes as per the "RRC" (Right Rotation Count) received.
Our implementation does not do any rotates when sending, only
when receiving, we rotate left as per the RRC count, to revert it.

/**
     * Rotate bytes as per the "RRC" (Right Rotation Count) received.
     * Our implementation does not do any rotates when sending, only
     * when receiving, we rotate left as per the RRC count, to revert it.
     */
    private void rotate() {
        if (rrc % tokenDataLen != 0) {
           rrc = rrc % tokenDataLen;
           byte[] newBytes = new byte[tokenDataLen];

           System.arraycopy(tokenData, rrc, newBytes, 0, tokenDataLen-rrc);
           System.arraycopy(tokenData, 0, newBytes, tokenDataLen-rrc, rrc);

           tokenData = newBytes;
        }
    }

    public final int getSequenceNumber() {
        return seqNumber;
    }

    
Computes the checksum based on the algorithm stored in the
tokenHeader.

Params:
  • data – the application data
  • offset – the offset where the data begins
  • len – the length of the application data
Throws:
  • GSSException – if an error occurs in the checksum calculation.
/**
     * Computes the checksum based on the algorithm stored in the
     * tokenHeader.
     *
     * @param data the application data
     * @param offset the offset where the data begins
     * @param len the length of the application data
     *
     * @throws GSSException if an error occurs in the checksum calculation.
     */
    byte[] getChecksum(byte[] data, int offset, int len)
        throws GSSException {

        //      debug("Will do getChecksum:\n");

        /*
         * For checksum calculation the token header bytes i.e., the first 16
         * bytes following the GSSHeader, are logically prepended to the
         * application data to bind the data to this particular token.
         *
         * Note: There is no such requirement wrt adding padding to the
         * application data for checksumming, although the cryptographic
         * algorithm used might itself apply some padding.
         */

        byte[] tokenHeaderBytes = tokenHeader.getBytes();

        // check confidentiality
        int conf_flag = tokenHeaderBytes[TOKEN_FLAG_POS] &
                                FLAG_WRAP_CONFIDENTIAL;

        // clear EC in token header for checksum calculation
        if ((conf_flag == 0) && (tokenId == WRAP_ID_v2)) {
            tokenHeaderBytes[4] = 0;
            tokenHeaderBytes[5] = 0;
        }
        return cipherHelper.calculateChecksum(tokenHeaderBytes, data,
                                                offset, len, key_usage);
    }


    
Constructs an empty MessageToken for the local context to send to
the peer. It also increments the local sequence number in the
Krb5Context instance it uses after obtaining the object lock for
it.

Params:
  • tokenId – the token id that should be contained in this token
  • context – the Kerberos context associated with this token
/**
     * Constructs an empty MessageToken for the local context to send to
     * the peer. It also increments the local sequence number in the
     * Krb5Context instance it uses after obtaining the object lock for
     * it.
     *
     * @param tokenId the token id that should be contained in this token
     * @param context the Kerberos context associated with this token
     */
    MessageToken_v2(int tokenId, Krb5Context context) throws GSSException {
        /*
          debug("\n============================");
          debug("\nMySessionKey=" +
          getHexBytes(context.getMySessionKey().getBytes()));
          debug("\nPeerSessionKey=" +
          getHexBytes(context.getPeerSessionKey().getBytes()));
          debug("\n============================\n");
        */
        init(tokenId, context);
        this.seqNumber = context.incrementMySequenceNumber();
    }

    private void init(int tokenId, Krb5Context context) throws GSSException {
        this.tokenId = tokenId;
        // Just for consistency check in Wrap
        this.confState = context.getConfState();

        this.initiator = context.isInitiator();

        this.cipherHelper = context.getCipherHelper(null);
        //    debug("In MessageToken.Cons");
    }

    
Encodes a MessageTokenHeader onto an OutputStream.

Params:
  • os – the OutputStream to which this should be written
Throws:
  • IOException – is an error occurs while writing to the OutputStream
/**
     * Encodes a MessageTokenHeader onto an OutputStream.
     *
     * @param os the OutputStream to which this should be written
     * @throws IOException is an error occurs while writing to the OutputStream
     */
    protected void encodeHeader(OutputStream os) throws IOException {
        tokenHeader.encode(os);
    }

    
Encodes a MessageToken_v2 onto an OutputStream.

Params:
  • os – the OutputStream to which this should be written
Throws:
  • IOException – is an error occurs while encoding the token
/**
     * Encodes a MessageToken_v2 onto an OutputStream.
     *
     * @param os the OutputStream to which this should be written
     * @throws IOException is an error occurs while encoding the token
     */
    public abstract void encode(OutputStream os) throws IOException;

    protected final byte[] getTokenHeader() {
        return (tokenHeader.getBytes());
    }

    // ******************************************* //
    //  I N N E R    C L A S S E S    F O L L O W
    // ******************************************* //

    
This inner class represents the initial portion of the message token.
It constitutes the first 16 bytes of the message token.

/**
     * This inner class represents the initial portion of the message token.
     * It constitutes the first 16 bytes of the message token.
     */
    class MessageTokenHeader {

         private int tokenId;
         private byte[] bytes = new byte[TOKEN_HEADER_SIZE];

         // Writes a new token header
         public MessageTokenHeader(int tokenId, boolean conf,
                boolean have_acceptor_subkey) throws GSSException {

            this.tokenId = tokenId;

            bytes[0] = (byte) (tokenId >>> 8);
            bytes[1] = (byte) (tokenId);

            // Flags (Note: MIT impl requires subkey)
            int flags = 0;
            flags = (initiator ? 0 : FLAG_SENDER_IS_ACCEPTOR) |
                     ((conf && tokenId != MIC_ID_v2) ?
                                FLAG_WRAP_CONFIDENTIAL : 0) |
                     (have_acceptor_subkey ? FLAG_ACCEPTOR_SUBKEY : 0);
            bytes[2] = (byte) flags;

            // filler
            bytes[3] = (byte) FILLER;

            if (tokenId == WRAP_ID_v2) {
                // EC field
                bytes[4] = (byte) 0;
                bytes[5] = (byte) 0;
                // RRC field
                bytes[6] = (byte) 0;
                bytes[7] = (byte) 0;
            } else if (tokenId == MIC_ID_v2) {
                // more filler for MicToken
                for (int i = 4; i < 8; i++) {
                    bytes[i] = (byte) FILLER;
                }
            }

            // Calculate SND_SEQ, only write 4 bytes from the 12th position
            writeBigEndian(seqNumber, bytes, 12);
        }

        
Reads a MessageTokenHeader from an InputStream and sets the
appropriate confidentiality and quality of protection
values in a MessageProp structure.

Params:
  • is – the InputStream to read from
  • prop – the MessageProp to populate
Throws:
  • IOException – is an error occurs while reading from the
InputStream
/**
         * Reads a MessageTokenHeader from an InputStream and sets the
         * appropriate confidentiality and quality of protection
         * values in a MessageProp structure.
         *
         * @param is the InputStream to read from
         * @param prop the MessageProp to populate
         * @throws IOException is an error occurs while reading from the
         * InputStream
         */
        public MessageTokenHeader(InputStream is, MessageProp prop, int tokId)
            throws IOException, GSSException {

            readFully(is, bytes, 0, TOKEN_HEADER_SIZE);
            tokenId = readInt(bytes, TOKEN_ID_POS);

            // validate Token ID
            if (tokenId != tokId) {
                throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
                    getTokenName(tokenId) + ":" + "Defective Token ID!");
            }

            /*
             * Validate new GSS TokenHeader
             */

            // valid acceptor_flag
            // If I am initiator, the received token should have ACCEPTOR on
            int acceptor_flag = (initiator ? FLAG_SENDER_IS_ACCEPTOR : 0);
            int flag = bytes[TOKEN_FLAG_POS] & FLAG_SENDER_IS_ACCEPTOR;
            if (flag != acceptor_flag) {
                throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
                        getTokenName(tokenId) + ":" + "Acceptor Flag Error!");
            }

            // check for confidentiality
            int conf_flag = bytes[TOKEN_FLAG_POS] & FLAG_WRAP_CONFIDENTIAL;
            if ((conf_flag == FLAG_WRAP_CONFIDENTIAL) &&
                (tokenId == WRAP_ID_v2)) {
                prop.setPrivacy(true);
            } else {
                prop.setPrivacy(false);
            }

            if (tokenId == WRAP_ID_v2) {
                // validate filler
                if ((bytes[3] & 0xff) != FILLER) {
                    throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
                        getTokenName(tokenId) + ":" + "Defective Token Filler!");
                }

                // read EC field
                ec = readBigEndian(bytes, TOKEN_EC_POS, 2);

                // read RRC field
                rrc = readBigEndian(bytes, TOKEN_RRC_POS, 2);
            } else if (tokenId == MIC_ID_v2) {
                for (int i = 3; i < 8; i++) {
                    if ((bytes[i] & 0xff) != FILLER) {
                        throw new GSSException(GSSException.DEFECTIVE_TOKEN,
                                -1, getTokenName(tokenId) + ":" +
                                "Defective Token Filler!");
                    }
                }
            }

            // set default QOP
            prop.setQOP(0);

            // sequence number
            seqNumber = readBigEndian(bytes, 0, 8);
        }

        
Encodes this MessageTokenHeader onto an OutputStream

Params:
  • os – the OutputStream to write to
Throws:
/**
         * Encodes this MessageTokenHeader onto an OutputStream
         * @param os the OutputStream to write to
         * @throws IOException is an error occurs while writing
         */
        public final void encode(OutputStream os) throws IOException {
            os.write(bytes);
        }


        
Returns the token id for the message token.

See Also:
Returns:the token id
/**
         * Returns the token id for the message token.
         * @return the token id
         * @see sun.security.jgss.krb5.Krb5Token#MIC_ID_v2
         * @see sun.security.jgss.krb5.Krb5Token#WRAP_ID_v2
         */
        public final int getTokenId() {
            return tokenId;
        }

        
Returns the bytes of this header.

Returns:8 bytes that form this header
/**
         * Returns the bytes of this header.
         * @return 8 bytes that form this header
         */
        public final byte[] getBytes() {
            return bytes;
        }
    } // end of class MessageTokenHeader
}