Java example source code file (CipherHelper.java)
The CipherHelper.java Java example source code/*
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*
* 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).
*
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package sun.security.jgss.krb5;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import org.ietf.jgss.*;
import java.security.MessageDigest;
import java.security.GeneralSecurityException;
import java.security.NoSuchAlgorithmException;
import sun.security.krb5.*;
import sun.security.krb5.internal.crypto.Des3;
import sun.security.krb5.internal.crypto.Aes128;
import sun.security.krb5.internal.crypto.Aes256;
import sun.security.krb5.internal.crypto.ArcFourHmac;
class CipherHelper {
// From draft-raeburn-cat-gssapi-krb5-3des-00
// Key usage values when deriving keys
private static final int KG_USAGE_SEAL = 22;
private static final int KG_USAGE_SIGN = 23;
private static final int KG_USAGE_SEQ = 24;
private static final int DES_CHECKSUM_SIZE = 8;
private static final int DES_IV_SIZE = 8;
private static final int AES_IV_SIZE = 16;
// ARCFOUR-HMAC
// Save first 8 octets of HMAC Sgn_Cksum
private static final int HMAC_CHECKSUM_SIZE = 8;
// key usage for MIC tokens used by MS
private static final int KG_USAGE_SIGN_MS = 15;
// debug flag
private static final boolean DEBUG = Krb5Util.DEBUG;
/**
* A zero initial vector to be used for checksum calculation and for
* DesCbc application data encryption/decryption.
*/
private static final byte[] ZERO_IV = new byte[DES_IV_SIZE];
private static final byte[] ZERO_IV_AES = new byte[AES_IV_SIZE];
private int etype;
private int sgnAlg, sealAlg;
private byte[] keybytes;
// new token format from draft-ietf-krb-wg-gssapi-cfx-07
// proto is used to determine new GSS token format for "newer" etypes
private int proto = 0;
CipherHelper(EncryptionKey key) throws GSSException {
etype = key.getEType();
keybytes = key.getBytes();
switch (etype) {
case EncryptedData.ETYPE_DES_CBC_CRC:
case EncryptedData.ETYPE_DES_CBC_MD5:
sgnAlg = MessageToken.SGN_ALG_DES_MAC_MD5;
sealAlg = MessageToken.SEAL_ALG_DES;
break;
case EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD:
sgnAlg = MessageToken.SGN_ALG_HMAC_SHA1_DES3_KD;
sealAlg = MessageToken.SEAL_ALG_DES3_KD;
break;
case EncryptedData.ETYPE_ARCFOUR_HMAC:
sgnAlg = MessageToken.SGN_ALG_HMAC_MD5_ARCFOUR;
sealAlg = MessageToken.SEAL_ALG_ARCFOUR_HMAC;
break;
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
sgnAlg = -1;
sealAlg = -1;
proto = 1;
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported encryption type: " + etype);
}
}
int getSgnAlg() {
return sgnAlg;
}
int getSealAlg() {
return sealAlg;
}
int getProto() {
return proto;
}
int getEType() {
return etype;
}
boolean isArcFour() {
boolean flag = false;
if (etype == EncryptedData.ETYPE_ARCFOUR_HMAC) {
flag = true;
}
return flag;
}
@SuppressWarnings("fallthrough")
byte[] calculateChecksum(int alg, byte[] header, byte[] trailer,
byte[] data, int start, int len, int tokenId) throws GSSException {
switch (alg) {
case MessageToken.SGN_ALG_DES_MAC_MD5:
/*
* With this sign algorithm, first an MD5 hash is computed on the
* application data. The 16 byte hash is then DesCbc encrypted.
*/
try {
MessageDigest md5 = MessageDigest.getInstance("MD5");
// debug("\t\tdata=[");
// debug(getHexBytes(checksumDataHeader,
// checksumDataHeader.length) + " ");
md5.update(header);
// debug(getHexBytes(data, start, len));
md5.update(data, start, len);
if (trailer != null) {
// debug(" " +
// getHexBytes(trailer,
// optionalTrailer.length));
md5.update(trailer);
}
// debug("]\n");
data = md5.digest();
start = 0;
len = data.length;
// System.out.println("\tMD5 Checksum is [" +
// getHexBytes(data) + "]\n");
header = null;
trailer = null;
} catch (NoSuchAlgorithmException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not get MD5 Message Digest - " + e.getMessage());
ge.initCause(e);
throw ge;
}
// fall through to encrypt checksum
case MessageToken.SGN_ALG_DES_MAC:
return getDesCbcChecksum(keybytes, header, data, start, len);
case MessageToken.SGN_ALG_HMAC_SHA1_DES3_KD:
byte[] buf;
int offset, total;
if (header == null && trailer == null) {
buf = data;
total = len;
offset = start;
} else {
total = ((header != null ? header.length : 0) + len +
(trailer != null ? trailer.length : 0));
buf = new byte[total];
int pos = 0;
if (header != null) {
System.arraycopy(header, 0, buf, 0, header.length);
pos = header.length;
}
System.arraycopy(data, start, buf, pos, len);
pos += len;
if (trailer != null) {
System.arraycopy(trailer, 0, buf, pos, trailer.length);
}
offset = 0;
}
try {
/*
Krb5Token.debug("\nkeybytes: " +
Krb5Token.getHexBytes(keybytes));
Krb5Token.debug("\nheader: " + (header == null ? "NONE" :
Krb5Token.getHexBytes(header)));
Krb5Token.debug("\ntrailer: " + (trailer == null ? "NONE" :
Krb5Token.getHexBytes(trailer)));
Krb5Token.debug("\ndata: " +
Krb5Token.getHexBytes(data, start, len));
Krb5Token.debug("\nbuf: " + Krb5Token.getHexBytes(buf, offset,
total));
*/
byte[] answer = Des3.calculateChecksum(keybytes,
KG_USAGE_SIGN, buf, offset, total);
// Krb5Token.debug("\nanswer: " +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use HMAC-SHA1-DES3-KD signing algorithm - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
case MessageToken.SGN_ALG_HMAC_MD5_ARCFOUR:
byte[] buffer;
int off, tot;
if (header == null && trailer == null) {
buffer = data;
tot = len;
off = start;
} else {
tot = ((header != null ? header.length : 0) + len +
(trailer != null ? trailer.length : 0));
buffer = new byte[tot];
int pos = 0;
if (header != null) {
System.arraycopy(header, 0, buffer, 0, header.length);
pos = header.length;
}
System.arraycopy(data, start, buffer, pos, len);
pos += len;
if (trailer != null) {
System.arraycopy(trailer, 0, buffer, pos, trailer.length);
}
off = 0;
}
try {
/*
Krb5Token.debug("\nkeybytes: " +
Krb5Token.getHexBytes(keybytes));
Krb5Token.debug("\nheader: " + (header == null ? "NONE" :
Krb5Token.getHexBytes(header)));
Krb5Token.debug("\ntrailer: " + (trailer == null ? "NONE" :
Krb5Token.getHexBytes(trailer)));
Krb5Token.debug("\ndata: " +
Krb5Token.getHexBytes(data, start, len));
Krb5Token.debug("\nbuffer: " +
Krb5Token.getHexBytes(buffer, off, tot));
*/
// for MIC tokens, key derivation salt is 15
// NOTE: Required for interoperability. The RC4-HMAC spec
// defines key_usage of 23, however all Kerberos impl.
// MS/Solaris/MIT all use key_usage of 15 for MIC tokens
int key_usage = KG_USAGE_SIGN;
if (tokenId == Krb5Token.MIC_ID) {
key_usage = KG_USAGE_SIGN_MS;
}
byte[] answer = ArcFourHmac.calculateChecksum(keybytes,
key_usage, buffer, off, tot);
// Krb5Token.debug("\nanswer: " +
// Krb5Token.getHexBytes(answer));
// Save first 8 octets of HMAC Sgn_Cksum
byte[] output = new byte[getChecksumLength()];
System.arraycopy(answer, 0, output, 0, output.length);
// Krb5Token.debug("\nanswer (trimmed): " +
// Krb5Token.getHexBytes(output));
return output;
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use HMAC_MD5_ARCFOUR signing algorithm - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported signing algorithm: " + sgnAlg);
}
}
// calculate Checksum for the new GSS tokens
byte[] calculateChecksum(byte[] header, byte[] data, int start, int len,
int key_usage) throws GSSException {
// total length
int total = ((header != null ? header.length : 0) + len);
// get_mic("plaintext-data" | "header")
byte[] buf = new byte[total];
// data
System.arraycopy(data, start, buf, 0, len);
// token header
if (header != null) {
System.arraycopy(header, 0, buf, len, header.length);
}
// Krb5Token.debug("\nAES calculate checksum on: " +
// Krb5Token.getHexBytes(buf));
switch (etype) {
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
try {
byte[] answer = Aes128.calculateChecksum(keybytes, key_usage,
buf, 0, total);
// Krb5Token.debug("\nAES128 checksum: " +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use AES128 signing algorithm - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
try {
byte[] answer = Aes256.calculateChecksum(keybytes, key_usage,
buf, 0, total);
// Krb5Token.debug("\nAES256 checksum: " +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use AES256 signing algorithm - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported encryption type: " + etype);
}
}
byte[] encryptSeq(byte[] ivec, byte[] plaintext, int start, int len)
throws GSSException {
switch (sgnAlg) {
case MessageToken.SGN_ALG_DES_MAC_MD5:
case MessageToken.SGN_ALG_DES_MAC:
try {
Cipher des = getInitializedDes(true, keybytes, ivec);
return des.doFinal(plaintext, start, len);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not encrypt sequence number using DES - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
case MessageToken.SGN_ALG_HMAC_SHA1_DES3_KD:
byte[] iv;
if (ivec.length == DES_IV_SIZE) {
iv = ivec;
} else {
iv = new byte[DES_IV_SIZE];
System.arraycopy(ivec, 0, iv, 0, DES_IV_SIZE);
}
try {
return Des3.encryptRaw(keybytes, KG_USAGE_SEQ, iv,
plaintext, start, len);
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not encrypt sequence number using DES3-KD - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
case MessageToken.SGN_ALG_HMAC_MD5_ARCFOUR:
// ivec passed is the checksum
byte[] checksum;
if (ivec.length == HMAC_CHECKSUM_SIZE) {
checksum = ivec;
} else {
checksum = new byte[HMAC_CHECKSUM_SIZE];
System.arraycopy(ivec, 0, checksum, 0, HMAC_CHECKSUM_SIZE);
}
try {
return ArcFourHmac.encryptSeq(keybytes, KG_USAGE_SEQ, checksum,
plaintext, start, len);
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not encrypt sequence number using RC4-HMAC - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported signing algorithm: " + sgnAlg);
}
}
byte[] decryptSeq(byte[] ivec, byte[] ciphertext, int start, int len)
throws GSSException {
switch (sgnAlg) {
case MessageToken.SGN_ALG_DES_MAC_MD5:
case MessageToken.SGN_ALG_DES_MAC:
try {
Cipher des = getInitializedDes(false, keybytes, ivec);
return des.doFinal(ciphertext, start, len);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not decrypt sequence number using DES - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
case MessageToken.SGN_ALG_HMAC_SHA1_DES3_KD:
byte[] iv;
if (ivec.length == DES_IV_SIZE) {
iv = ivec;
} else {
iv = new byte[8];
System.arraycopy(ivec, 0, iv, 0, DES_IV_SIZE);
}
try {
return Des3.decryptRaw(keybytes, KG_USAGE_SEQ, iv,
ciphertext, start, len);
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not decrypt sequence number using DES3-KD - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
case MessageToken.SGN_ALG_HMAC_MD5_ARCFOUR:
// ivec passed is the checksum
byte[] checksum;
if (ivec.length == HMAC_CHECKSUM_SIZE) {
checksum = ivec;
} else {
checksum = new byte[HMAC_CHECKSUM_SIZE];
System.arraycopy(ivec, 0, checksum, 0, HMAC_CHECKSUM_SIZE);
}
try {
return ArcFourHmac.decryptSeq(keybytes, KG_USAGE_SEQ, checksum,
ciphertext, start, len);
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not decrypt sequence number using RC4-HMAC - " +
e.getMessage());
ge.initCause(e);
throw ge;
}
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported signing algorithm: " + sgnAlg);
}
}
int getChecksumLength() throws GSSException {
switch (etype) {
case EncryptedData.ETYPE_DES_CBC_CRC:
case EncryptedData.ETYPE_DES_CBC_MD5:
return DES_CHECKSUM_SIZE;
case EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD:
return Des3.getChecksumLength();
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
return Aes128.getChecksumLength();
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
return Aes256.getChecksumLength();
case EncryptedData.ETYPE_ARCFOUR_HMAC:
// only first 8 octets of HMAC Sgn_Cksum are used
return HMAC_CHECKSUM_SIZE;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported encryption type: " + etype);
}
}
void decryptData(WrapToken token, byte[] ciphertext, int cStart, int cLen,
byte[] plaintext, int pStart) throws GSSException {
/*
Krb5Token.debug("decryptData : ciphertext = " +
Krb5Token.getHexBytes(ciphertext));
*/
switch (sealAlg) {
case MessageToken.SEAL_ALG_DES:
desCbcDecrypt(token, getDesEncryptionKey(keybytes),
ciphertext, cStart, cLen, plaintext, pStart);
break;
case MessageToken.SEAL_ALG_DES3_KD:
des3KdDecrypt(token, ciphertext, cStart, cLen, plaintext, pStart);
break;
case MessageToken.SEAL_ALG_ARCFOUR_HMAC:
arcFourDecrypt(token, ciphertext, cStart, cLen, plaintext, pStart);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported seal algorithm: " + sealAlg);
}
}
// decrypt data in the new GSS tokens
void decryptData(WrapToken_v2 token, byte[] ciphertext, int cStart,
int cLen, byte[] plaintext, int pStart, int key_usage)
throws GSSException {
/*
Krb5Token.debug("decryptData : ciphertext = " +
Krb5Token.getHexBytes(ciphertext));
*/
switch (etype) {
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
aes128Decrypt(token, ciphertext, cStart, cLen,
plaintext, pStart, key_usage);
break;
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
aes256Decrypt(token, ciphertext, cStart, cLen,
plaintext, pStart, key_usage);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported etype: " + etype);
}
}
void decryptData(WrapToken token, InputStream cipherStream, int cLen,
byte[] plaintext, int pStart)
throws GSSException, IOException {
switch (sealAlg) {
case MessageToken.SEAL_ALG_DES:
desCbcDecrypt(token, getDesEncryptionKey(keybytes),
cipherStream, cLen, plaintext, pStart);
break;
case MessageToken.SEAL_ALG_DES3_KD:
// Read encrypted data from stream
byte[] ciphertext = new byte[cLen];
try {
Krb5Token.readFully(cipherStream, ciphertext, 0, cLen);
} catch (IOException e) {
GSSException ge = new GSSException(
GSSException.DEFECTIVE_TOKEN, -1,
"Cannot read complete token");
ge.initCause(e);
throw ge;
}
des3KdDecrypt(token, ciphertext, 0, cLen, plaintext, pStart);
break;
case MessageToken.SEAL_ALG_ARCFOUR_HMAC:
// Read encrypted data from stream
byte[] ctext = new byte[cLen];
try {
Krb5Token.readFully(cipherStream, ctext, 0, cLen);
} catch (IOException e) {
GSSException ge = new GSSException(
GSSException.DEFECTIVE_TOKEN, -1,
"Cannot read complete token");
ge.initCause(e);
throw ge;
}
arcFourDecrypt(token, ctext, 0, cLen, plaintext, pStart);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported seal algorithm: " + sealAlg);
}
}
void decryptData(WrapToken_v2 token, InputStream cipherStream, int cLen,
byte[] plaintext, int pStart, int key_usage)
throws GSSException, IOException {
// Read encrypted data from stream
byte[] ciphertext = new byte[cLen];
try {
Krb5Token.readFully(cipherStream, ciphertext, 0, cLen);
} catch (IOException e) {
GSSException ge = new GSSException(
GSSException.DEFECTIVE_TOKEN, -1,
"Cannot read complete token");
ge.initCause(e);
throw ge;
}
switch (etype) {
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
aes128Decrypt(token, ciphertext, 0, cLen,
plaintext, pStart, key_usage);
break;
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
aes256Decrypt(token, ciphertext, 0, cLen,
plaintext, pStart, key_usage);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported etype: " + etype);
}
}
void encryptData(WrapToken token, byte[] confounder, byte[] plaintext,
int start, int len, byte[] padding, OutputStream os)
throws GSSException, IOException {
switch (sealAlg) {
case MessageToken.SEAL_ALG_DES:
// Encrypt on the fly and write
Cipher des = getInitializedDes(true, getDesEncryptionKey(keybytes),
ZERO_IV);
CipherOutputStream cos = new CipherOutputStream(os, des);
// debug(getHexBytes(confounder, confounder.length));
cos.write(confounder);
// debug(" " + getHexBytes(plaintext, start, len));
cos.write(plaintext, start, len);
// debug(" " + getHexBytes(padding, padding.length));
cos.write(padding);
break;
case MessageToken.SEAL_ALG_DES3_KD:
byte[] ctext = des3KdEncrypt(confounder, plaintext, start, len,
padding);
// Write to stream
os.write(ctext);
break;
case MessageToken.SEAL_ALG_ARCFOUR_HMAC:
byte[] ciphertext = arcFourEncrypt(token, confounder, plaintext,
start, len, padding);
// Write to stream
os.write(ciphertext);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported seal algorithm: " + sealAlg);
}
}
/*
* Encrypt data in the new GSS tokens
*
* Wrap Tokens (with confidentiality)
* { Encrypt(16-byte confounder | plaintext | 16-byte token_header) |
* 12-byte HMAC }
* where HMAC is on {16-byte confounder | plaintext | 16-byte token_header}
* HMAC is not encrypted; it is appended at the end.
*/
byte[] encryptData(WrapToken_v2 token, byte[] confounder, byte[] tokenHeader,
byte[] plaintext, int start, int len, int key_usage)
throws GSSException {
switch (etype) {
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
return aes128Encrypt(confounder, tokenHeader,
plaintext, start, len, key_usage);
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
return aes256Encrypt(confounder, tokenHeader,
plaintext, start, len, key_usage);
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported etype: " + etype);
}
}
void encryptData(WrapToken token, byte[] confounder, byte[] plaintext,
int pStart, int pLen, byte[] padding, byte[] ciphertext, int cStart)
throws GSSException {
switch (sealAlg) {
case MessageToken.SEAL_ALG_DES:
int pos = cStart;
// Encrypt and write
Cipher des = getInitializedDes(true, getDesEncryptionKey(keybytes),
ZERO_IV);
try {
// debug(getHexBytes(confounder, confounder.length));
pos += des.update(confounder, 0, confounder.length,
ciphertext, pos);
// debug(" " + getHexBytes(dataBytes, dataOffset, dataLen));
pos += des.update(plaintext, pStart, pLen,
ciphertext, pos);
// debug(" " + getHexBytes(padding, padding.length));
des.update(padding, 0, padding.length,
ciphertext, pos);
des.doFinal();
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use DES Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
break;
case MessageToken.SEAL_ALG_DES3_KD:
byte[] ctext = des3KdEncrypt(confounder, plaintext, pStart, pLen,
padding);
System.arraycopy(ctext, 0, ciphertext, cStart, ctext.length);
break;
case MessageToken.SEAL_ALG_ARCFOUR_HMAC:
byte[] ctext2 = arcFourEncrypt(token, confounder, plaintext, pStart,
pLen, padding);
System.arraycopy(ctext2, 0, ciphertext, cStart, ctext2.length);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported seal algorithm: " + sealAlg);
}
}
/*
* Encrypt data in the new GSS tokens
*
* Wrap Tokens (with confidentiality)
* { Encrypt(16-byte confounder | plaintext | 16-byte token_header) |
* 12-byte HMAC }
* where HMAC is on {16-byte confounder | plaintext | 16-byte token_header}
* HMAC is not encrypted; it is appended at the end.
*/
int encryptData(WrapToken_v2 token, byte[] confounder, byte[] tokenHeader,
byte[] plaintext, int pStart, int pLen, byte[] ciphertext, int cStart,
int key_usage) throws GSSException {
byte[] ctext = null;
switch (etype) {
case EncryptedData.ETYPE_AES128_CTS_HMAC_SHA1_96:
ctext = aes128Encrypt(confounder, tokenHeader,
plaintext, pStart, pLen, key_usage);
break;
case EncryptedData.ETYPE_AES256_CTS_HMAC_SHA1_96:
ctext = aes256Encrypt(confounder, tokenHeader,
plaintext, pStart, pLen, key_usage);
break;
default:
throw new GSSException(GSSException.FAILURE, -1,
"Unsupported etype: " + etype);
}
System.arraycopy(ctext, 0, ciphertext, cStart, ctext.length);
return ctext.length;
}
// --------------------- DES methods
/**
* Computes the DesCbc checksum based on the algorithm published in FIPS
* Publication 113. This involves applying padding to the data passed
* in, then performing DesCbc encryption on the data with a zero initial
* vector, and finally returning the last 8 bytes of the encryption
* result.
*
* @param key the bytes for the DES key
* @param header a header to process first before the data is.
* @param data the data to checksum
* @param offset the offset where the data begins
* @param len the length of the data
* @throws GSSException when an error occuse in the encryption
*/
private byte[] getDesCbcChecksum(byte key[],
byte[] header,
byte[] data, int offset, int len)
throws GSSException {
Cipher des = getInitializedDes(true, key, ZERO_IV);
int blockSize = des.getBlockSize();
/*
* Here the data need not be a multiple of the blocksize
* (8). Encrypt and throw away results for all blocks except for
* the very last block.
*/
byte[] finalBlock = new byte[blockSize];
int numBlocks = len / blockSize;
int lastBytes = len % blockSize;
if (lastBytes == 0) {
// No need for padding. Save last block from application data
numBlocks -= 1;
System.arraycopy(data, offset + numBlocks*blockSize,
finalBlock, 0, blockSize);
} else {
System.arraycopy(data, offset + numBlocks*blockSize,
finalBlock, 0, lastBytes);
// Zero padding automatically done
}
try {
byte[] temp = new byte[Math.max(blockSize,
(header == null? blockSize : header.length))];
if (header != null) {
// header will be null when doing DES-MD5 Checksum
des.update(header, 0, header.length, temp, 0);
}
// Iterate over all but the last block
for (int i = 0; i < numBlocks; i++) {
des.update(data, offset, blockSize,
temp, 0);
offset += blockSize;
}
// Now process the final block
byte[] retVal = new byte[blockSize];
des.update(finalBlock, 0, blockSize, retVal, 0);
des.doFinal();
return retVal;
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use DES Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
}
/**
* Obtains an initialized DES cipher.
*
* @param encryptMode true if encryption is desired, false is decryption
* is desired.
* @param key the bytes for the DES key
* @param ivBytes the initial vector bytes
*/
private final Cipher getInitializedDes(boolean encryptMode, byte[] key,
byte[] ivBytes)
throws GSSException {
try {
IvParameterSpec iv = new IvParameterSpec(ivBytes);
SecretKey jceKey = (SecretKey) (new SecretKeySpec(key, "DES"));
Cipher desCipher = Cipher.getInstance("DES/CBC/NoPadding");
desCipher.init(
(encryptMode ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE),
jceKey, iv);
return desCipher;
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
e.getMessage());
ge.initCause(e);
throw ge;
}
}
/**
* Helper routine to decrypt fromm a byte array and write the
* application data straight to an output array with minimal
* buffer copies. The confounder and the padding are stored
* separately and not copied into this output array.
* @param key the DES key to use
* @param cipherText the encrypted data
* @param offset the offset for the encrypted data
* @param len the length of the encrypted data
* @param dataOutBuf the output buffer where the application data
* should be writte
* @param dataOffset the offser where the application data should
* be written.
* @throws GSSException is an error occurs while decrypting the
* data
*/
private void desCbcDecrypt(WrapToken token, byte[] key, byte[] cipherText,
int offset, int len, byte[] dataOutBuf, int dataOffset)
throws GSSException {
try {
int temp = 0;
Cipher des = getInitializedDes(false, key, ZERO_IV);
/*
* Remove the counfounder first.
* CONFOUNDER_SIZE is one DES block ie 8 bytes.
*/
temp = des.update(cipherText, offset, WrapToken.CONFOUNDER_SIZE,
token.confounder);
// temp should be CONFOUNDER_SIZE
// debug("\n\ttemp is " + temp + " and CONFOUNDER_SIZE is "
// + CONFOUNDER_SIZE);
offset += WrapToken.CONFOUNDER_SIZE;
len -= WrapToken.CONFOUNDER_SIZE;
/*
* len is a multiple of 8 due to padding.
* Decrypt all blocks directly into the output buffer except for
* the very last block. Remove the trailing padding bytes from the
* very last block and copy that into the output buffer.
*/
int blockSize = des.getBlockSize();
int numBlocks = len / blockSize - 1;
// Iterate over all but the last block
for (int i = 0; i < numBlocks; i++) {
temp = des.update(cipherText, offset, blockSize,
dataOutBuf, dataOffset);
// temp should be blockSize
// debug("\n\ttemp is " + temp + " and blockSize is "
// + blockSize);
offset += blockSize;
dataOffset += blockSize;
}
// Now process the last block
byte[] finalBlock = new byte[blockSize];
des.update(cipherText, offset, blockSize, finalBlock);
des.doFinal();
/*
* There is always at least one padding byte. The padding bytes
* are all the value of the number of padding bytes.
*/
int padSize = finalBlock[blockSize - 1];
if (padSize < 1 || padSize > 8)
throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
"Invalid padding on Wrap Token");
token.padding = WrapToken.pads[padSize];
blockSize -= padSize;
// Copy this last block into the output buffer
System.arraycopy(finalBlock, 0, dataOutBuf, dataOffset,
blockSize);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use DES cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
}
/**
* Helper routine to decrypt from an InputStream and write the
* application data straight to an output array with minimal
* buffer copies. The confounder and the padding are stored
* separately and not copied into this output array.
* @param key the DES key to use
* @param is the InputStream from which the cipher text should be
* read
* @param len the length of the ciphertext data
* @param dataOutBuf the output buffer where the application data
* should be writte
* @param dataOffset the offser where the application data should
* be written.
* @throws GSSException is an error occurs while decrypting the
* data
*/
private void desCbcDecrypt(WrapToken token, byte[] key,
InputStream is, int len, byte[] dataOutBuf, int dataOffset)
throws GSSException, IOException {
int temp = 0;
Cipher des = getInitializedDes(false, key, ZERO_IV);
WrapTokenInputStream truncatedInputStream =
new WrapTokenInputStream(is, len);
CipherInputStream cis = new CipherInputStream(truncatedInputStream,
des);
/*
* Remove the counfounder first.
* CONFOUNDER_SIZE is one DES block ie 8 bytes.
*/
temp = cis.read(token.confounder);
len -= temp;
// temp should be CONFOUNDER_SIZE
// debug("Got " + temp + " bytes; CONFOUNDER_SIZE is "
// + CONFOUNDER_SIZE + "\n");
// debug("Confounder is " + getHexBytes(confounder) + "\n");
/*
* len is a multiple of 8 due to padding.
* Decrypt all blocks directly into the output buffer except for
* the very last block. Remove the trailing padding bytes from the
* very last block and copy that into the output buffer.
*/
int blockSize = des.getBlockSize();
int numBlocks = len / blockSize - 1;
// Iterate over all but the last block
for (int i = 0; i < numBlocks; i++) {
// debug("dataOffset is " + dataOffset + "\n");
temp = cis.read(dataOutBuf, dataOffset, blockSize);
// temp should be blockSize
// debug("Got " + temp + " bytes and blockSize is "
// + blockSize + "\n");
// debug("Bytes are: "
// + getHexBytes(dataOutBuf, dataOffset, temp) + "\n");
dataOffset += blockSize;
}
// Now process the last block
byte[] finalBlock = new byte[blockSize];
// debug("Will call read on finalBlock" + "\n");
temp = cis.read(finalBlock);
// temp should be blockSize
/*
debug("Got " + temp + " bytes and blockSize is "
+ blockSize + "\n");
debug("Bytes are: "
+ getHexBytes(finalBlock, 0, temp) + "\n");
debug("Will call doFinal" + "\n");
*/
try {
des.doFinal();
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use DES cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
/*
* There is always at least one padding byte. The padding bytes
* are all the value of the number of padding bytes.
*/
int padSize = finalBlock[blockSize - 1];
if (padSize < 1 || padSize > 8)
throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
"Invalid padding on Wrap Token");
token.padding = WrapToken.pads[padSize];
blockSize -= padSize;
// Copy this last block into the output buffer
System.arraycopy(finalBlock, 0, dataOutBuf, dataOffset,
blockSize);
}
private static byte[] getDesEncryptionKey(byte[] key)
throws GSSException {
/*
* To meet export control requirements, double check that the
* key being used is no longer than 64 bits.
*
* Note that from a protocol point of view, an
* algorithm that is not DES will be rejected before this
* point. Also, a DES key that is not 64 bits will be
* rejected by a good JCE provider.
*/
if (key.length > 8)
throw new GSSException(GSSException.FAILURE, -100,
"Invalid DES Key!");
byte[] retVal = new byte[key.length];
for (int i = 0; i < key.length; i++)
retVal[i] = (byte)(key[i] ^ 0xf0); // RFC 1964, Section 1.2.2
return retVal;
}
// ---- DES3-KD methods
private void des3KdDecrypt(WrapToken token, byte[] ciphertext,
int cStart, int cLen, byte[] plaintext, int pStart)
throws GSSException {
byte[] ptext;
try {
ptext = Des3.decryptRaw(keybytes, KG_USAGE_SEAL, ZERO_IV,
ciphertext, cStart, cLen);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use DES3-KD Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
/*
Krb5Token.debug("\ndes3KdDecrypt in: " +
Krb5Token.getHexBytes(ciphertext, cStart, cLen));
Krb5Token.debug("\ndes3KdDecrypt plain: " +
Krb5Token.getHexBytes(ptext));
*/
// Strip out confounder and padding
/*
* There is always at least one padding byte. The padding bytes
* are all the value of the number of padding bytes.
*/
int padSize = ptext[ptext.length - 1];
if (padSize < 1 || padSize > 8)
throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
"Invalid padding on Wrap Token");
token.padding = WrapToken.pads[padSize];
int len = ptext.length - WrapToken.CONFOUNDER_SIZE - padSize;
System.arraycopy(ptext, WrapToken.CONFOUNDER_SIZE,
plaintext, pStart, len);
// Needed to calculate checksum
System.arraycopy(ptext, 0, token.confounder,
0, WrapToken.CONFOUNDER_SIZE);
}
private byte[] des3KdEncrypt(byte[] confounder, byte[] plaintext,
int start, int len, byte[] padding) throws GSSException {
// [confounder | plaintext | padding]
byte[] all = new byte[confounder.length + len + padding.length];
System.arraycopy(confounder, 0, all, 0, confounder.length);
System.arraycopy(plaintext, start, all, confounder.length, len);
System.arraycopy(padding, 0, all, confounder.length + len,
padding.length);
// Krb5Token.debug("\ndes3KdEncrypt:" + Krb5Token.getHexBytes(all));
// Encrypt
try {
byte[] answer = Des3.encryptRaw(keybytes, KG_USAGE_SEAL, ZERO_IV,
all, 0, all.length);
// Krb5Token.debug("\ndes3KdEncrypt encrypted:" +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use DES3-KD Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
}
// ---- RC4-HMAC methods
private void arcFourDecrypt(WrapToken token, byte[] ciphertext,
int cStart, int cLen, byte[] plaintext, int pStart)
throws GSSException {
// obtain Sequence number needed for decryption
// first decrypt the Sequence Number using checksum
byte[] seqNum = decryptSeq(token.getChecksum(),
token.getEncSeqNumber(), 0, 8);
byte[] ptext;
try {
ptext = ArcFourHmac.decryptRaw(keybytes, KG_USAGE_SEAL, ZERO_IV,
ciphertext, cStart, cLen, seqNum);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use ArcFour Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
/*
Krb5Token.debug("\narcFourDecrypt in: " +
Krb5Token.getHexBytes(ciphertext, cStart, cLen));
Krb5Token.debug("\narcFourDecrypt plain: " +
Krb5Token.getHexBytes(ptext));
*/
// Strip out confounder and padding
/*
* There is always at least one padding byte. The padding bytes
* are all the value of the number of padding bytes.
*/
int padSize = ptext[ptext.length - 1];
if (padSize < 1)
throw new GSSException(GSSException.DEFECTIVE_TOKEN, -1,
"Invalid padding on Wrap Token");
token.padding = WrapToken.pads[padSize];
int len = ptext.length - WrapToken.CONFOUNDER_SIZE - padSize;
System.arraycopy(ptext, WrapToken.CONFOUNDER_SIZE,
plaintext, pStart, len);
// Krb5Token.debug("\narcFourDecrypt plaintext: " +
// Krb5Token.getHexBytes(plaintext));
// Needed to calculate checksum
System.arraycopy(ptext, 0, token.confounder,
0, WrapToken.CONFOUNDER_SIZE);
}
private byte[] arcFourEncrypt(WrapToken token, byte[] confounder,
byte[] plaintext, int start, int len, byte[] padding)
throws GSSException {
// [confounder | plaintext | padding]
byte[] all = new byte[confounder.length + len + padding.length];
System.arraycopy(confounder, 0, all, 0, confounder.length);
System.arraycopy(plaintext, start, all, confounder.length, len);
System.arraycopy(padding, 0, all, confounder.length + len,
padding.length);
// get the token Sequence Number required for encryption
// Note: When using this RC4 based encryption type, the sequence number
// is always sent in big-endian rather than little-endian order.
byte[] seqNum = new byte[4];
WrapToken.writeBigEndian(token.getSequenceNumber(), seqNum);
// Krb5Token.debug("\narcFourEncrypt:" + Krb5Token.getHexBytes(all));
// Encrypt
try {
byte[] answer = ArcFourHmac.encryptRaw(keybytes, KG_USAGE_SEAL,
seqNum, all, 0, all.length);
// Krb5Token.debug("\narcFourEncrypt encrypted:" +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use ArcFour Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
}
// ---- AES methods
private byte[] aes128Encrypt(byte[] confounder, byte[] tokenHeader,
byte[] plaintext, int start, int len, int key_usage)
throws GSSException {
// encrypt { AES-plaintext-data | filler | header }
// AES-plaintext-data { confounder | plaintext }
// WrapToken = { tokenHeader |
// Encrypt (confounder | plaintext | tokenHeader ) | HMAC }
byte[] all = new byte[confounder.length + len + tokenHeader.length];
System.arraycopy(confounder, 0, all, 0, confounder.length);
System.arraycopy(plaintext, start, all, confounder.length, len);
System.arraycopy(tokenHeader, 0, all, confounder.length+len,
tokenHeader.length);
// Krb5Token.debug("\naes128Encrypt:" + Krb5Token.getHexBytes(all));
try {
byte[] answer = Aes128.encryptRaw(keybytes, key_usage,
ZERO_IV_AES,
all, 0, all.length);
// Krb5Token.debug("\naes128Encrypt encrypted:" +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use AES128 Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
}
private void aes128Decrypt(WrapToken_v2 token, byte[] ciphertext,
int cStart, int cLen, byte[] plaintext, int pStart, int key_usage)
throws GSSException {
byte[] ptext = null;
try {
ptext = Aes128.decryptRaw(keybytes, key_usage,
ZERO_IV_AES, ciphertext, cStart, cLen);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use AES128 Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
/*
Krb5Token.debug("\naes128Decrypt in: " +
Krb5Token.getHexBytes(ciphertext, cStart, cLen));
Krb5Token.debug("\naes128Decrypt plain: " +
Krb5Token.getHexBytes(ptext));
Krb5Token.debug("\naes128Decrypt ptext: " +
Krb5Token.getHexBytes(ptext));
*/
// Strip out confounder and token header
int len = ptext.length - WrapToken_v2.CONFOUNDER_SIZE -
WrapToken_v2.TOKEN_HEADER_SIZE;
System.arraycopy(ptext, WrapToken_v2.CONFOUNDER_SIZE,
plaintext, pStart, len);
/*
Krb5Token.debug("\naes128Decrypt plaintext: " +
Krb5Token.getHexBytes(plaintext, pStart, len));
*/
}
private byte[] aes256Encrypt(byte[] confounder, byte[] tokenHeader,
byte[] plaintext, int start, int len, int key_usage)
throws GSSException {
// encrypt { AES-plaintext-data | filler | header }
// AES-plaintext-data { confounder | plaintext }
// WrapToken = { tokenHeader |
// Encrypt (confounder | plaintext | tokenHeader ) | HMAC }
byte[] all = new byte[confounder.length + len + tokenHeader.length];
System.arraycopy(confounder, 0, all, 0, confounder.length);
System.arraycopy(plaintext, start, all, confounder.length, len);
System.arraycopy(tokenHeader, 0, all, confounder.length+len,
tokenHeader.length);
// Krb5Token.debug("\naes256Encrypt:" + Krb5Token.getHexBytes(all));
try {
byte[] answer = Aes256.encryptRaw(keybytes, key_usage,
ZERO_IV_AES, all, 0, all.length);
// Krb5Token.debug("\naes256Encrypt encrypted:" +
// Krb5Token.getHexBytes(answer));
return answer;
} catch (Exception e) {
// GeneralSecurityException, KrbCryptoException
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use AES256 Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
}
private void aes256Decrypt(WrapToken_v2 token, byte[] ciphertext,
int cStart, int cLen, byte[] plaintext, int pStart, int key_usage)
throws GSSException {
byte[] ptext;
try {
ptext = Aes256.decryptRaw(keybytes, key_usage,
ZERO_IV_AES, ciphertext, cStart, cLen);
} catch (GeneralSecurityException e) {
GSSException ge = new GSSException(GSSException.FAILURE, -1,
"Could not use AES128 Cipher - " + e.getMessage());
ge.initCause(e);
throw ge;
}
/*
Krb5Token.debug("\naes256Decrypt in: " +
Krb5Token.getHexBytes(ciphertext, cStart, cLen));
Krb5Token.debug("\naes256Decrypt plain: " +
Krb5Token.getHexBytes(ptext));
Krb5Token.debug("\naes256Decrypt ptext: " +
Krb5Token.getHexBytes(ptext));
*/
// Strip out confounder and token header
int len = ptext.length - WrapToken_v2.CONFOUNDER_SIZE -
WrapToken_v2.TOKEN_HEADER_SIZE;
System.arraycopy(ptext, WrapToken_v2.CONFOUNDER_SIZE,
plaintext, pStart, len);
/*
Krb5Token.debug("\naes128Decrypt plaintext: " +
Krb5Token.getHexBytes(plaintext, pStart, len));
*/
}
/**
* This class provides a truncated inputstream needed by WrapToken. The
* truncated inputstream is passed to CipherInputStream. It prevents
* the CipherInputStream from treating the bytes of the following token
* as part fo the ciphertext for this token.
*/
class WrapTokenInputStream extends InputStream {
private InputStream is;
private int length;
private int remaining;
private int temp;
public WrapTokenInputStream(InputStream is, int length) {
this.is = is;
this.length = length;
remaining = length;
}
public final int read() throws IOException {
if (remaining == 0)
return -1;
else {
temp = is.read();
if (temp != -1)
remaining -= temp;
return temp;
}
}
public final int read(byte[] b) throws IOException {
if (remaining == 0)
return -1;
else {
temp = Math.min(remaining, b.length);
temp = is.read(b, 0, temp);
if (temp != -1)
remaining -= temp;
return temp;
}
}
public final int read(byte[] b,
int off,
int len) throws IOException {
if (remaining == 0)
return -1;
else {
temp = Math.min(remaining, len);
temp = is.read(b, off, temp);
if (temp != -1)
remaining -= temp;
return temp;
}
}
public final long skip(long n) throws IOException {
if (remaining == 0)
return 0;
else {
temp = (int) Math.min(remaining, n);
temp = (int) is.skip(temp);
remaining -= temp;
return temp;
}
}
public final int available() throws IOException {
return Math.min(remaining, is.available());
}
public final void close() throws IOException {
remaining = 0;
}
}
}
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