/*
* Copyright (c) 2000, 2019, 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
* by Oracle in the LICENSE file that accompanied this code.
*
* 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,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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/*
* (C) Copyright IBM Corp. 1999 All Rights Reserved.
* Copyright 1997 The Open Group Research Institute. All rights reserved.
*/
package sun.security.krb5;
import java.util.Arrays;
import sun.security.util.*;
import sun.security.krb5.internal.*;
import sun.security.krb5.internal.crypto.*;
import java.io.IOException;
import java.math.BigInteger;
/**
* This class encapsulates the concept of a Kerberos checksum.
*/
public class Checksum {
private int cksumType;
private byte[] checksum;
// ----------------------------------------------+-------------+-----------
// Checksum type |sumtype |checksum
// |value | size
// ----------------------------------------------+-------------+-----------
public static final int CKSUMTYPE_NULL = 0; // 0
public static final int CKSUMTYPE_CRC32 = 1; // 4
public static final int CKSUMTYPE_RSA_MD4 = 2; // 16
public static final int CKSUMTYPE_RSA_MD4_DES = 3; // 24
public static final int CKSUMTYPE_DES_MAC = 4; // 16
public static final int CKSUMTYPE_DES_MAC_K = 5; // 8
public static final int CKSUMTYPE_RSA_MD4_DES_K = 6; // 16
public static final int CKSUMTYPE_RSA_MD5 = 7; // 16
public static final int CKSUMTYPE_RSA_MD5_DES = 8; // 24
// draft-ietf-krb-wg-crypto-07.txt
public static final int CKSUMTYPE_HMAC_SHA1_DES3_KD = 12; // 20
// draft-raeburn-krb-rijndael-krb-07.txt
public static final int CKSUMTYPE_HMAC_SHA1_96_AES128 = 15; // 96
public static final int CKSUMTYPE_HMAC_SHA1_96_AES256 = 16; // 96
// draft-brezak-win2k-krb-rc4-hmac-04.txt
public static final int CKSUMTYPE_HMAC_MD5_ARCFOUR = -138;
// default checksum type, -1 if not set
static int CKSUMTYPE_DEFAULT;
static int SAFECKSUMTYPE_DEFAULT;
private static boolean DEBUG = Krb5.DEBUG;
static {
initStatic();
}
public static void initStatic() {
String temp = null;
Config cfg = null;
try {
cfg = Config.getInstance();
temp = cfg.get("libdefaults", "default_checksum");
if (temp != null) {
CKSUMTYPE_DEFAULT = Config.getType(temp);
} else {
CKSUMTYPE_DEFAULT = -1;
}
} catch (Exception exc) {
if (DEBUG) {
System.out.println("Exception in getting default checksum "+
"value from the configuration. " +
"No default checksum set.");
exc.printStackTrace();
}
CKSUMTYPE_DEFAULT = -1;
}
try {
temp = cfg.get("libdefaults", "safe_checksum_type");
if (temp != null)
{
SAFECKSUMTYPE_DEFAULT = Config.getType(temp);
} else {
SAFECKSUMTYPE_DEFAULT = -1;
}
} catch (Exception exc) {
if (DEBUG) {
System.out.println("Exception in getting safe default " +
"checksum value " +
"from the configuration Setting. " +
"No safe default checksum set.");
exc.printStackTrace();
}
SAFECKSUMTYPE_DEFAULT = -1;
}
}
/**
* Constructs a new Checksum using the raw data and type.
*
* This constructor is only used by Authenticator Checksum
* {@link sun.security.jgss.krb5.InitialToken.OverloadedChecksum}
* where the checksum type must be 0x8003
* (see https://tools.ietf.org/html/rfc4121#section-4.1.1)
* and checksum field/value is used to convey service flags,
* channel bindings, and optional delegation information.
* This special type does NOT have a {@link CksumType} and has its
* own calculating and verification rules. It does has the same
* ASN.1 encoding though.
*
* @data the byte array of checksum.
* @new_cksumType the type of checksum.
*/
public Checksum(byte[] data, int new_cksumType) {
cksumType = new_cksumType;
checksum = data;
}
/**
* Constructs a new Checksum by calculating over the data using
* the specified checksum type. If the checksum is unkeyed, key
* and usage are ignored.
*
* @param new_cksumType the type of checksum. If set to -1, the
* {@linkplain EType#checksumType() mandatory checksum type}
* for the encryption type of {@code key} will be used
* @param data the data that needs to be performed a checksum calculation on
* @param key the key used by a keyed checksum
* @param usage the usage used by a keyed checksum
*/
public Checksum(int new_cksumType, byte[] data,
EncryptionKey key, int usage)
throws KdcErrException, KrbApErrException, KrbCryptoException {
if (new_cksumType == -1) {
cksumType = EType.getInstance(key.getEType()).checksumType();
} else {
cksumType = new_cksumType;
}
checksum = CksumType.getInstance(cksumType).calculateChecksum(
data, data.length, key.getBytes(), usage);
}
/**
* Verifies the keyed checksum over the data passed in.
*/
public boolean verifyKeyedChecksum(byte[] data, EncryptionKey key, int usage)
throws KdcErrException, KrbApErrException, KrbCryptoException {
CksumType cksumEngine = CksumType.getInstance(cksumType);
if (!cksumEngine.isKeyed()) {
throw new KrbApErrException(Krb5.KRB_AP_ERR_INAPP_CKSUM);
} else {
return cksumEngine.verifyChecksum(
data, data.length, key.getBytes(), checksum, usage);
}
}
/**
* Verifies the checksum over the data passed in. The checksum might
* be a keyed or not.
*
* =============== ATTENTION! Use with care ==================
* According to https://tools.ietf.org/html/rfc3961#section-6.1,
* An unkeyed checksum should only be used "in limited circumstances
* where the lack of a key does not provide a window for an attack,
* preferably as part of an encrypted message".
*/
public boolean verifyAnyChecksum(byte[] data, EncryptionKey key, int usage)
throws KdcErrException, KrbCryptoException {
return CksumType.getInstance(cksumType).verifyChecksum(
data, data.length, key.getBytes(), checksum, usage);
}
boolean isEqual(Checksum cksum) throws KdcErrException {
if (cksumType != cksum.cksumType) {
return false;
}
return CksumType.isChecksumEqual(checksum, cksum.checksum);
}
/**
* Constructs an instance of Checksum from an ASN.1 encoded representation.
* @param encoding a single DER-encoded value.
* @exception Asn1Exception if an error occurs while decoding an ASN1
* encoded data.
* @exception IOException if an I/O error occurs while reading encoded data.
*
*/
public Checksum(DerValue encoding) throws Asn1Exception, IOException {
DerValue der;
if (encoding.getTag() != DerValue.tag_Sequence) {
throw new Asn1Exception(Krb5.ASN1_BAD_ID);
}
der = encoding.getData().getDerValue();
if ((der.getTag() & (byte)0x1F) == (byte)0x00) {
cksumType = der.getData().getBigInteger().intValue();
}
else
throw new Asn1Exception(Krb5.ASN1_BAD_ID);
der = encoding.getData().getDerValue();
if ((der.getTag() & (byte)0x1F) == (byte)0x01) {
checksum = der.getData().getOctetString();
}
else
throw new Asn1Exception(Krb5.ASN1_BAD_ID);
if (encoding.getData().available() > 0) {
throw new Asn1Exception(Krb5.ASN1_BAD_ID);
}
}
/**
* Encodes a Checksum object.
* <![CDATA[
* Checksum ::= SEQUENCE {
* cksumtype [0] Int32,
* checksum [1] OCTET STRING
* }
* ]]>
*
*
* This definition reflects the Network Working Group RFC 4120
* specification available at
*
* http://www.ietf.org/rfc/rfc4120.txt.
* @return byte array of enocded Checksum.
* @exception Asn1Exception if an error occurs while decoding an
* ASN1 encoded data.
* @exception IOException if an I/O error occurs while reading
* encoded data.
*
*/
public byte[] asn1Encode() throws Asn1Exception, IOException {
DerOutputStream bytes = new DerOutputStream();
DerOutputStream temp = new DerOutputStream();
temp.putInteger(BigInteger.valueOf(cksumType));
bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT,
true, (byte)0x00), temp);
temp = new DerOutputStream();
temp.putOctetString(checksum);
bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT,
true, (byte)0x01), temp);
temp = new DerOutputStream();
temp.write(DerValue.tag_Sequence, bytes);
return temp.toByteArray();
}
/**
* Parse (unmarshal) a checksum object from a DER input stream. This form
* parsing might be used when expanding a value which is part of
* a constructed sequence and uses explicitly tagged type.
*
* @exception Asn1Exception if an error occurs while decoding an
* ASN1 encoded data.
* @exception IOException if an I/O error occurs while reading
* encoded data.
* @param data the Der input stream value, which contains one or more
* marshaled value.
* @param explicitTag tag number.
* @param optional indicates if this data field is optional
* @return an instance of Checksum.
*
*/
public static Checksum parse(DerInputStream data,
byte explicitTag, boolean optional)
throws Asn1Exception, IOException {
if ((optional) &&
(((byte)data.peekByte() & (byte)0x1F) != explicitTag)) {
return null;
}
DerValue der = data.getDerValue();
if (explicitTag != (der.getTag() & (byte)0x1F)) {
throw new Asn1Exception(Krb5.ASN1_BAD_ID);
} else {
DerValue subDer = der.getData().getDerValue();
return new Checksum(subDer);
}
}
/**
* Returns the raw bytes of the checksum, not in ASN.1 encoded form.
*/
public final byte[] getBytes() {
return checksum;
}
public final int getType() {
return cksumType;
}
@Override public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof Checksum)) {
return false;
}
try {
return isEqual((Checksum)obj);
} catch (KdcErrException kee) {
return false;
}
}
@Override public int hashCode() {
int result = 17;
result = 37 * result + cksumType;
if (checksum != null) {
result = 37 * result + Arrays.hashCode(checksum);
}
return result;
}
}