/**
* 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.wss4j.common.kerberos;
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.ApplicationRequestDecoder;
import org.apache.directory.server.kerberos.shared.messages.ApplicationRequest;
import org.apache.directory.server.kerberos.shared.messages.components.EncTicketPart;
import org.apache.directory.server.kerberos.shared.messages.value.EncryptionKey;
import javax.security.auth.Subject;
import javax.security.auth.kerberos.KerberosKey;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;
import java.util.Set;
public class KerberosTokenDecoderImpl implements KerberosTokenDecoder {
private static final String KERBEROS_OID = "1.2.840.113554.1.2.2";
private byte[] serviceTicket;
private Subject subject;
private boolean decoded = false;
private EncTicketPart encTicketPart;
/**
* Clear all internal information
*/
public void clear() {
serviceTicket = null;
subject = null;
decoded = false;
encTicketPart = null;
}
/**
* Set the AP-REQ Kerberos Token
*
* @param token the AP-REQ Kerberos Token
*/
public void setToken(byte[] token) {
serviceTicket = token;
}
/**
* Set the Subject
*
* @param subject the Subject
*/
public void setSubject(Subject subject) {
this.subject = subject;
}
/**
* Get the session key from the token
*
* @return the session key from the token
*/
public byte[] getSessionKey() throws KerberosTokenDecoderException {
if (!decoded) {
decodeServiceTicket();
}
if (encTicketPart != null && encTicketPart.getSessionKey() != null) {
return encTicketPart.getSessionKey().getKeyValue();
}
return null;
}
/**
* Get the client principal name from the decoded service ticket.
*
* @return the client principal name
*/
public String getClientPrincipalName() throws KerberosTokenDecoderException {
if (!decoded) {
decodeServiceTicket();
}
return encTicketPart.getClientPrincipal().toString();
}
// Decode the service ticket.
private synchronized void decodeServiceTicket() throws KerberosTokenDecoderException {
parseServiceTicket(serviceTicket);
decoded = true;
}
// Parses the service ticket (GSS AP-REQ token)
private void parseServiceTicket(byte[] ticket) throws KerberosTokenDecoderException {
try {
// I didn't find a better way how to parse this Kerberos Message...
org.bouncycastle.asn1.ASN1InputStream asn1InputStream =
new org.bouncycastle.asn1.ASN1InputStream(new ByteArrayInputStream(ticket));
org.bouncycastle.asn1.DERApplicationSpecific derToken =
(org.bouncycastle.asn1.DERApplicationSpecific) asn1InputStream.readObject();
if (derToken == null || !derToken.isConstructed()) {
asn1InputStream.close();
throw new KerberosTokenDecoderException("invalid kerberos token");
}
asn1InputStream.close();
asn1InputStream = new org.bouncycastle.asn1.ASN1InputStream(new ByteArrayInputStream(derToken.getContents()));
org.bouncycastle.asn1.ASN1ObjectIdentifier kerberosOid =
(org.bouncycastle.asn1.ASN1ObjectIdentifier) asn1InputStream.readObject();
if (!kerberosOid.getId().equals(KERBEROS_OID)) {
asn1InputStream.close();
throw new KerberosTokenDecoderException("invalid kerberos token");
}
int readLowByte = asn1InputStream.read() & 0xff;
int readHighByte = asn1InputStream.read() & 0xff;
int read = (readHighByte << 8) + readLowByte; //NOPMD
if (read != 0x01) {
throw new KerberosTokenDecoderException("invalid kerberos token");
}
ApplicationRequestDecoder applicationRequestDecoder = new ApplicationRequestDecoder();
ApplicationRequest applicationRequest = applicationRequestDecoder.decode(toByteArray(asn1InputStream));
final int encryptionType = applicationRequest.getTicket().getEncPart().getEType().getOrdinal();
KerberosKey kerberosKey = getKrbKey(subject, encryptionType);
EncryptionKey encryptionKey =
new EncryptionKey(EncryptionType.getTypeByOrdinal(encryptionType), kerberosKey.getEncoded());
CipherTextHandler cipherTextHandler = new CipherTextHandler();
this.encTicketPart = (EncTicketPart) cipherTextHandler.unseal(
EncTicketPart.class, encryptionKey, applicationRequest.getTicket().getEncPart(), KeyUsage.NUMBER2);
} catch (KerberosException e) {
throw new KerberosTokenDecoderException(e);
} catch (IOException e) {
throw new KerberosTokenDecoderException(e);
}
}
private KerberosKey getKrbKey(Subject sub, int keyType) {
Set<Object> creds = sub.getPrivateCredentials(Object.class);
for (Iterator<Object> i = creds.iterator(); i.hasNext(); ) {
Object cred = i.next();
if (cred instanceof KerberosKey) {
KerberosKey key = (KerberosKey) cred;
if (key.getKeyType() == keyType) {
return (KerberosKey) cred;
}
}
}
return null;
}
private static byte[] toByteArray(InputStream inputStream) throws IOException {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
int read;
byte[] buf = new byte[1024];
while ((read = inputStream.read(buf)) != -1) {
byteArrayOutputStream.write(buf, 0, read);
}
return byteArrayOutputStream.toByteArray();
}
}