jcifs.pac.Pac Maven / Gradle / Ivy

/*
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.pac;


import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;


@SuppressWarnings ( "javadoc" )
public class Pac {

    private PacLogonInfo logonInfo;
    private PacCredentialType credentialType;
    private PacSignature serverSignature;
    private PacSignature kdcSignature;


    public Pac ( byte[] data, Key key ) throws PACDecodingException {
        byte[] checksumData = data.clone();
        try {
            PacDataInputStream pacStream = new PacDataInputStream(new DataInputStream(new ByteArrayInputStream(data)));

            if ( data.length <= 8 )
                throw new PACDecodingException("Empty PAC");

            int bufferCount = pacStream.readInt();
            int version = pacStream.readInt();

            if ( version != PacConstants.PAC_VERSION ) {
                throw new PACDecodingException("Unrecognized PAC version " + version);
            }

            for ( int bufferIndex = 0; bufferIndex < bufferCount; bufferIndex++ ) {
                int bufferType = pacStream.readInt();
                int bufferSize = pacStream.readInt();
                long bufferOffset = pacStream.readLong();
                byte[] bufferData = new byte[bufferSize];
                System.arraycopy(data, (int) bufferOffset, bufferData, 0, bufferSize);

                switch ( bufferType ) {
                case PacConstants.LOGON_INFO:
                    // PAC Credential Information
                    this.logonInfo = new PacLogonInfo(bufferData);
                    break;
                case PacConstants.CREDENTIAL_TYPE:
                    // PAC Credential Type
                    this.credentialType = new PacCredentialType(bufferData);
                    break;
                case PacConstants.SERVER_CHECKSUM:
                    // PAC Server Signature
                    this.serverSignature = new PacSignature(bufferData);
                    // Clear signature from checksum copy
                    for ( int i = 0; i < bufferSize; i++ )
                        checksumData[ (int) bufferOffset + 4 + i ] = 0;
                    break;
                case PacConstants.PRIVSVR_CHECKSUM:
                    // PAC KDC Signature
                    this.kdcSignature = new PacSignature(bufferData);
                    // Clear signature from checksum copy
                    for ( int i = 0; i < bufferSize; i++ )
                        checksumData[ (int) bufferOffset + 4 + i ] = 0;
                    break;
                default:
                }
            }
        }
        catch ( IOException e ) {
            throw new PACDecodingException("Malformed PAC", e);
        }

        PacMac mac = new PacMac();
        try {
            mac.init(key);
            mac.update(checksumData);
        }
        catch ( NoSuchAlgorithmException e ) {
            throw new PACDecodingException("Could not compute MAC", e);
        }

        byte checksum[] = mac.doFinal();
        if ( !Arrays.equals(this.serverSignature.getChecksum(), checksum) )
            throw new PACDecodingException("Invalid PAC signature");
    }


    public PacLogonInfo getLogonInfo () {
        return this.logonInfo;
    }


    public PacCredentialType getCredentialType () {
        return this.credentialType;
    }


    public PacSignature getServerSignature () {
        return this.serverSignature;
    }


    public PacSignature getKdcSignature () {
        return this.kdcSignature;
    }
}