J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 3 | * |
| 4 | * This code is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU General Public License version 2 only, as |
| 6 | * published by the Free Software Foundation. Sun designates this |
| 7 | * particular file as subject to the "Classpath" exception as provided |
| 8 | * by Sun in the LICENSE file that accompanied this code. |
| 9 | * |
| 10 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 13 | * version 2 for more details (a copy is included in the LICENSE file that |
| 14 | * accompanied this code). |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License version |
| 17 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 18 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 19 | * |
| 20 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 21 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 22 | * have any questions. |
| 23 | */ |
| 24 | |
| 25 | /* |
| 26 | * (C) Copyright IBM Corp. 1999 All Rights Reserved. |
| 27 | * Copyright 1997 The Open Group Research Institute. All rights reserved. |
| 28 | */ |
| 29 | |
| 30 | package sun.security.krb5.internal.crypto; |
| 31 | |
| 32 | import sun.security.krb5.Checksum; |
| 33 | import sun.security.krb5.Confounder; |
| 34 | import sun.security.krb5.KrbCryptoException; |
| 35 | import sun.security.krb5.internal.*; |
| 36 | import javax.crypto.Cipher; |
| 37 | import javax.crypto.SecretKey; |
| 38 | import javax.crypto.spec.DESKeySpec; |
| 39 | import java.security.MessageDigest; |
| 40 | import java.security.Provider; |
| 41 | import java.security.Security; |
| 42 | import java.security.InvalidKeyException; |
| 43 | |
| 44 | public final class RsaMd5DesCksumType extends CksumType { |
| 45 | |
| 46 | public RsaMd5DesCksumType() { |
| 47 | } |
| 48 | |
| 49 | public int confounderSize() { |
| 50 | return 8; |
| 51 | } |
| 52 | |
| 53 | public int cksumType() { |
| 54 | return Checksum.CKSUMTYPE_RSA_MD5_DES; |
| 55 | } |
| 56 | |
| 57 | public boolean isSafe() { |
| 58 | return true; |
| 59 | } |
| 60 | |
| 61 | public int cksumSize() { |
| 62 | return 24; |
| 63 | } |
| 64 | |
| 65 | public int keyType() { |
| 66 | return Krb5.KEYTYPE_DES; |
| 67 | } |
| 68 | |
| 69 | public int keySize() { |
| 70 | return 8; |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Calculates keyed checksum. |
| 75 | * @param data the data used to generate the checksum. |
| 76 | * @param size length of the data. |
| 77 | * @param key the key used to encrypt the checksum. |
| 78 | * @return keyed checksum. |
| 79 | * |
| 80 | * @modified by Yanni Zhang, 12/08/99. |
| 81 | */ |
| 82 | public byte[] calculateKeyedChecksum(byte[] data, int size, byte[] key, |
| 83 | int usage) throws KrbCryptoException { |
| 84 | //prepend confounder |
| 85 | byte[] new_data = new byte[size + confounderSize()]; |
| 86 | byte[] conf = Confounder.bytes(confounderSize()); |
| 87 | System.arraycopy(conf, 0, new_data, 0, confounderSize()); |
| 88 | System.arraycopy(data, 0, new_data, confounderSize(), size); |
| 89 | |
| 90 | //calculate md5 cksum |
| 91 | byte[] mdc_cksum = calculateChecksum(new_data, new_data.length); |
| 92 | byte[] cksum = new byte[cksumSize()]; |
| 93 | System.arraycopy(conf, 0, cksum, 0, confounderSize()); |
| 94 | System.arraycopy(mdc_cksum, 0, cksum, confounderSize(), |
| 95 | cksumSize() - confounderSize()); |
| 96 | |
| 97 | //compute modified key |
| 98 | byte[] new_key = new byte[keySize()]; |
| 99 | System.arraycopy(key, 0, new_key, 0, key.length); |
| 100 | for (int i = 0; i < new_key.length; i++) |
| 101 | new_key[i] = (byte)(new_key[i] ^ 0xf0); |
| 102 | //check for weak keys |
| 103 | try { |
| 104 | if (DESKeySpec.isWeak(new_key, 0)) { |
| 105 | new_key[7] = (byte)(new_key[7] ^ 0xF0); |
| 106 | } |
| 107 | } catch (InvalidKeyException ex) { |
| 108 | // swallow, since it should never happen |
| 109 | } |
| 110 | byte[] ivec = new byte[new_key.length]; |
| 111 | |
| 112 | //des-cbc encrypt |
| 113 | byte[] enc_cksum = new byte[cksum.length]; |
| 114 | Des.cbc_encrypt(cksum, enc_cksum, new_key, ivec, true); |
| 115 | return enc_cksum; |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Verifies keyed checksum. |
| 120 | * @param data the data. |
| 121 | * @param size the length of data. |
| 122 | * @param key the key used to encrypt the checksum. |
| 123 | * @param checksum |
| 124 | * @return true if verification is successful. |
| 125 | * |
| 126 | * @modified by Yanni Zhang, 12/08/99. |
| 127 | */ |
| 128 | public boolean verifyKeyedChecksum(byte[] data, int size, |
| 129 | byte[] key, byte[] checksum, int usage) throws KrbCryptoException { |
| 130 | //decrypt checksum |
| 131 | byte[] cksum = decryptKeyedChecksum(checksum, key); |
| 132 | |
| 133 | //prepend confounder |
| 134 | byte[] new_data = new byte[size + confounderSize()]; |
| 135 | System.arraycopy(cksum, 0, new_data, 0, confounderSize()); |
| 136 | System.arraycopy(data, 0, new_data, confounderSize(), size); |
| 137 | |
| 138 | byte[] new_cksum = calculateChecksum(new_data, new_data.length); |
| 139 | //extract original cksum value |
| 140 | byte[] orig_cksum = new byte[cksumSize() - confounderSize()]; |
| 141 | System.arraycopy(cksum, confounderSize(), orig_cksum, 0, |
| 142 | cksumSize() - confounderSize()); |
| 143 | |
| 144 | return isChecksumEqual(orig_cksum, new_cksum); |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Decrypts keyed checksum. |
| 149 | * @param enc_cksum the buffer for encrypted checksum. |
| 150 | * @param key the key. |
| 151 | * @return the checksum. |
| 152 | * |
| 153 | * @modified by Yanni Zhang, 12/08/99. |
| 154 | */ |
| 155 | private byte[] decryptKeyedChecksum(byte[] enc_cksum, byte[] key) throws KrbCryptoException { |
| 156 | //compute modified key |
| 157 | byte[] new_key = new byte[keySize()]; |
| 158 | System.arraycopy(key, 0, new_key, 0, key.length); |
| 159 | for (int i = 0; i < new_key.length; i++) |
| 160 | new_key[i] = (byte)(new_key[i] ^ 0xf0); |
| 161 | //check for weak keys |
| 162 | try { |
| 163 | if (DESKeySpec.isWeak(new_key, 0)) { |
| 164 | new_key[7] = (byte)(new_key[7] ^ 0xF0); |
| 165 | } |
| 166 | } catch (InvalidKeyException ex) { |
| 167 | // swallow, since it should never happen |
| 168 | } |
| 169 | byte[] ivec = new byte[new_key.length]; |
| 170 | |
| 171 | byte[] cksum = new byte[enc_cksum.length]; |
| 172 | Des.cbc_encrypt(enc_cksum, cksum, new_key, ivec, false); |
| 173 | return cksum; |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * Calculates checksum using MD5. |
| 178 | * @param data the data used to generate the checksum. |
| 179 | * @param size length of the data. |
| 180 | * @return the checksum. |
| 181 | * |
| 182 | * @modified by Yanni Zhang, 12/08/99. |
| 183 | */ |
| 184 | public byte[] calculateChecksum(byte[] data, int size) throws KrbCryptoException{ |
| 185 | MessageDigest md5; |
| 186 | byte[] result = null; |
| 187 | try { |
| 188 | md5 = MessageDigest.getInstance("MD5"); |
| 189 | } catch (Exception e) { |
| 190 | throw new KrbCryptoException("JCE provider may not be installed. " + e.getMessage()); |
| 191 | } |
| 192 | try { |
| 193 | md5.update(data); |
| 194 | result = md5.digest(); |
| 195 | } catch (Exception e) { |
| 196 | throw new KrbCryptoException(e.getMessage()); |
| 197 | } |
| 198 | return result; |
| 199 | } |
| 200 | |
| 201 | } |