001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 *
019 */
020 package org.apache.directory.server.kerberos.shared.crypto.checksum;
021
022
023 import java.util.Collections;
024 import java.util.HashMap;
025 import java.util.Map;
026
027 import org.apache.directory.server.kerberos.shared.crypto.encryption.Aes128CtsSha1Encryption;
028 import org.apache.directory.server.kerberos.shared.crypto.encryption.Aes256CtsSha1Encryption;
029 import org.apache.directory.server.kerberos.shared.crypto.encryption.Des3CbcSha1KdEncryption;
030 import org.apache.directory.server.kerberos.shared.crypto.encryption.KeyUsage;
031 import org.apache.directory.server.kerberos.shared.exceptions.ErrorType;
032 import org.apache.directory.server.kerberos.shared.exceptions.KerberosException;
033 import org.apache.directory.server.kerberos.shared.messages.value.Checksum;
034
035
036 /**
037 * A Hashed Adapter encapsulating checksum engines for performing integrity checks.
038 *
039 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
040 * @version $Rev$, $Date$
041 */
042 public class ChecksumHandler
043 {
044 /** A map of the default encodable class names to the encoder class names. */
045 private static final Map DEFAULT_CHECKSUMS;
046
047 static
048 {
049 Map<ChecksumType, Class> map = new HashMap<ChecksumType, Class>();
050
051 map.put( ChecksumType.HMAC_MD5, HmacMd5Checksum.class );
052 map.put( ChecksumType.HMAC_SHA1_96_AES128, Aes128CtsSha1Encryption.class );
053 map.put( ChecksumType.HMAC_SHA1_96_AES256, Aes256CtsSha1Encryption.class );
054 map.put( ChecksumType.HMAC_SHA1_DES3_KD, Des3CbcSha1KdEncryption.class );
055 map.put( ChecksumType.RSA_MD5, RsaMd5Checksum.class );
056
057 DEFAULT_CHECKSUMS = Collections.unmodifiableMap( map );
058 }
059
060
061 /**
062 * Calculate a checksum based on raw bytes and an (optional) key for keyed checksums.
063 *
064 * @param checksumType
065 * @param bytes
066 * @param key
067 * @param usage
068 * @return The {@link Checksum}.
069 * @throws KerberosException
070 */
071 public Checksum calculateChecksum( ChecksumType checksumType, byte[] bytes, byte[] key, KeyUsage usage )
072 throws KerberosException
073 {
074 if ( !DEFAULT_CHECKSUMS.containsKey( checksumType ) )
075 {
076 throw new KerberosException( ErrorType.KDC_ERR_SUMTYPE_NOSUPP );
077 }
078
079 ChecksumEngine digester = getEngine( checksumType );
080 return new Checksum( checksumType, digester.calculateChecksum( bytes, key, usage ) );
081 }
082
083
084 /**
085 * Verify a checksum by providing the raw bytes and an (optional) key for keyed checksums.
086 *
087 * @param checksum
088 * @param bytes
089 * @param key
090 * @param usage
091 * @throws KerberosException
092 */
093 public void verifyChecksum( Checksum checksum, byte[] bytes, byte[] key, KeyUsage usage ) throws KerberosException
094 {
095 if ( checksum == null )
096 {
097 throw new KerberosException( ErrorType.KRB_AP_ERR_INAPP_CKSUM );
098 }
099
100 if ( !DEFAULT_CHECKSUMS.containsKey( checksum.getChecksumType() ) )
101 {
102 throw new KerberosException( ErrorType.KDC_ERR_SUMTYPE_NOSUPP );
103 }
104
105 ChecksumType checksumType = checksum.getChecksumType();
106 ChecksumEngine digester = getEngine( checksumType );
107 Checksum newChecksum = new Checksum( checksumType, digester.calculateChecksum( bytes, key, usage ) );
108
109 if ( !newChecksum.equals( checksum ) )
110 {
111 throw new KerberosException( ErrorType.KRB_AP_ERR_MODIFIED );
112 }
113 }
114
115
116 private ChecksumEngine getEngine( ChecksumType checksumType ) throws KerberosException
117 {
118 Class clazz = ( Class ) DEFAULT_CHECKSUMS.get( checksumType );
119
120 if ( clazz == null )
121 {
122 throw new KerberosException( ErrorType.KDC_ERR_SUMTYPE_NOSUPP );
123 }
124
125 try
126 {
127 return ( ChecksumEngine ) clazz.newInstance();
128 }
129 catch ( IllegalAccessException iae )
130 {
131 throw new KerberosException( ErrorType.KDC_ERR_SUMTYPE_NOSUPP, iae );
132 }
133 catch ( InstantiationException ie )
134 {
135 throw new KerberosException( ErrorType.KDC_ERR_SUMTYPE_NOSUPP, ie );
136 }
137 }
138 }