| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| */ |
| package org.apache.directory.server.kerberos.sam; |
| |
| |
| import java.io.IOException; |
| |
| import javax.security.auth.kerberos.KerberosKey; |
| |
| import org.apache.directory.server.kerberos.shared.crypto.encryption.CipherTextHandler; |
| import org.apache.directory.server.kerberos.shared.crypto.encryption.EncryptionType; |
| import org.apache.directory.server.kerberos.shared.crypto.encryption.KeyUsage; |
| import org.apache.directory.server.kerberos.shared.exceptions.KerberosException; |
| import org.apache.directory.server.kerberos.shared.io.decoder.EncryptedDataDecoder; |
| import org.apache.directory.server.kerberos.shared.messages.value.EncryptedData; |
| import org.apache.directory.server.kerberos.shared.messages.value.EncryptedTimeStamp; |
| import org.apache.directory.server.kerberos.shared.messages.value.EncryptionKey; |
| import org.apache.directory.server.kerberos.shared.messages.value.KerberosTime; |
| |
| |
| /** |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| * @version $Rev$, $Date$ |
| */ |
| public class TimestampChecker implements KeyIntegrityChecker |
| { |
| private static final long FIVE_MINUTES = 300000; |
| private static final CipherTextHandler cipherTextHandler = new CipherTextHandler(); |
| |
| |
| public boolean checkKeyIntegrity( byte[] encryptedData, KerberosKey kerberosKey ) |
| { |
| EncryptionType keyType = EncryptionType.getTypeByOrdinal( kerberosKey.getKeyType() ); |
| EncryptionKey key = new EncryptionKey( keyType, kerberosKey.getEncoded() ); |
| |
| try |
| { |
| /* |
| * Since the pre-auth value is of type PA-ENC-TIMESTAMP, it should be a valid |
| * ASN.1 PA-ENC-TS-ENC structure, so we can decode it into EncryptedData. |
| */ |
| EncryptedData sadValue = EncryptedDataDecoder.decode( encryptedData ); |
| |
| /* |
| * Decrypt the EncryptedData structure to get the PA-ENC-TS-ENC. Decode the |
| * decrypted timestamp into our timestamp object. |
| */ |
| EncryptedTimeStamp timestamp = ( EncryptedTimeStamp ) cipherTextHandler.unseal( EncryptedTimeStamp.class, |
| key, sadValue, KeyUsage.NUMBER1 ); |
| |
| /* |
| * Since we got here we must have a valid timestamp structure that we can |
| * validate to be within a five minute skew. |
| */ |
| KerberosTime time = timestamp.getTimeStamp(); |
| |
| if ( time.isInClockSkew( FIVE_MINUTES ) ) |
| { |
| return true; |
| } |
| } |
| catch ( IOException ioe ) |
| { |
| return false; |
| } |
| catch ( KerberosException ke ) |
| { |
| return false; |
| } |
| catch ( ClassCastException cce ) |
| { |
| return false; |
| } |
| |
| return false; |
| } |
| } |