J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2007 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.security.ssl; |
| 27 | |
| 28 | import java.io.*; |
| 29 | import java.security.*; |
| 30 | import java.security.interfaces.*; |
| 31 | |
| 32 | import javax.net.ssl.*; |
| 33 | |
| 34 | import sun.security.krb5.EncryptionKey; |
| 35 | import sun.security.krb5.EncryptedData; |
| 36 | import sun.security.krb5.KrbException; |
| 37 | import sun.security.krb5.internal.crypto.KeyUsage; |
| 38 | |
| 39 | /** |
| 40 | * This is the Kerberos premaster secret in the Kerberos client key |
| 41 | * exchange message (CLIENT --> SERVER); it holds the |
| 42 | * Kerberos-encrypted pre-master secret. The secret is encrypted using the |
| 43 | * Kerberos session key. The padding and size of the resulting message |
| 44 | * depends on the session key type, but the pre-master secret is |
| 45 | * always exactly 48 bytes. |
| 46 | * |
| 47 | */ |
| 48 | final class KerberosPreMasterSecret { |
| 49 | |
| 50 | private ProtocolVersion protocolVersion; // preMaster [0,1] |
| 51 | private byte preMaster[]; // 48 bytes |
| 52 | private byte encrypted[]; |
| 53 | |
| 54 | /** |
| 55 | * Constructor used by client to generate premaster secret. |
| 56 | * |
| 57 | * Client randomly creates a pre-master secret and encrypts it |
| 58 | * using the Kerberos session key; only the server can decrypt |
| 59 | * it, using the session key available in the service ticket. |
| 60 | * |
| 61 | * @param protocolVersion used to set preMaster[0,1] |
| 62 | * @param generator random number generator for generating premaster secret |
| 63 | * @param sessionKey Kerberos session key for encrypting premaster secret |
| 64 | */ |
| 65 | KerberosPreMasterSecret(ProtocolVersion protocolVersion, |
| 66 | SecureRandom generator, EncryptionKey sessionKey) throws IOException { |
| 67 | |
| 68 | if (sessionKey.getEType() == |
| 69 | EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD) { |
| 70 | throw new IOException( |
| 71 | "session keys with des3-cbc-hmac-sha1-kd encryption type " + |
| 72 | "are not supported for TLS Kerberos cipher suites"); |
| 73 | } |
| 74 | |
| 75 | this.protocolVersion = protocolVersion; |
| 76 | preMaster = generatePreMaster(generator, protocolVersion); |
| 77 | |
| 78 | // Encrypt premaster secret |
| 79 | try { |
| 80 | EncryptedData eData = new EncryptedData(sessionKey, preMaster, |
| 81 | KeyUsage.KU_UNKNOWN); |
| 82 | encrypted = eData.getBytes(); // not ASN.1 encoded. |
| 83 | |
| 84 | } catch (KrbException e) { |
| 85 | throw (SSLKeyException)new SSLKeyException |
| 86 | ("Kerberos premaster secret error").initCause(e); |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | /* |
| 91 | * Constructor used by server to decrypt encrypted premaster secret. |
| 92 | * The protocol version in preMaster[0,1] must match either currentVersion |
| 93 | * or clientVersion, otherwise, the premaster secret is set to |
| 94 | * a random one to foil possible attack. |
| 95 | * |
| 96 | * @param currentVersion version of protocol being used |
| 97 | * @param clientVersion version requested by client |
| 98 | * @param generator random number generator used to generate |
| 99 | * bogus premaster secret if premaster secret verification fails |
| 100 | * @param input input stream from which to read the encrypted |
| 101 | * premaster secret |
| 102 | * @param sessionKey Kerberos session key to be used for decryption |
| 103 | */ |
| 104 | KerberosPreMasterSecret(ProtocolVersion currentVersion, |
| 105 | ProtocolVersion clientVersion, |
| 106 | SecureRandom generator, HandshakeInStream input, |
| 107 | EncryptionKey sessionKey) throws IOException { |
| 108 | |
| 109 | // Extract encrypted premaster secret from message |
| 110 | encrypted = input.getBytes16(); |
| 111 | |
| 112 | if (HandshakeMessage.debug != null && Debug.isOn("handshake")) { |
| 113 | if (encrypted != null) { |
| 114 | Debug.println(System.out, |
| 115 | "encrypted premaster secret", encrypted); |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | if (sessionKey.getEType() == |
| 120 | EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD) { |
| 121 | throw new IOException( |
| 122 | "session keys with des3-cbc-hmac-sha1-kd encryption type " + |
| 123 | "are not supported for TLS Kerberos cipher suites"); |
| 124 | } |
| 125 | |
| 126 | // Decrypt premaster secret |
| 127 | try { |
| 128 | EncryptedData data = new EncryptedData(sessionKey.getEType(), |
| 129 | null /* optional kvno */, encrypted); |
| 130 | |
| 131 | byte[] temp = data.decrypt(sessionKey, KeyUsage.KU_UNKNOWN); |
| 132 | if (HandshakeMessage.debug != null && Debug.isOn("handshake")) { |
| 133 | if (encrypted != null) { |
| 134 | Debug.println(System.out, |
| 135 | "decrypted premaster secret", temp); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | // Reset data stream after decryption, remove redundant bytes |
| 140 | preMaster = data.reset(temp, false); |
| 141 | |
| 142 | protocolVersion = ProtocolVersion.valueOf(preMaster[0], |
| 143 | preMaster[1]); |
| 144 | if (HandshakeMessage.debug != null && Debug.isOn("handshake")) { |
| 145 | System.out.println("Kerberos PreMasterSecret version: " |
| 146 | + protocolVersion); |
| 147 | } |
| 148 | } catch (Exception e) { |
| 149 | // catch exception & process below |
| 150 | preMaster = null; |
| 151 | protocolVersion = currentVersion; |
| 152 | } |
| 153 | |
| 154 | // check if the premaster secret version is ok |
| 155 | // the specification says that it must be the maximum version supported |
| 156 | // by the client from its ClientHello message. However, many |
| 157 | // implementations send the negotiated version, so accept both |
| 158 | // NOTE that we may be comparing two unsupported version numbers in |
| 159 | // the second case, which is why we cannot use object references |
| 160 | // equality in this special case |
| 161 | boolean versionMismatch = (protocolVersion != currentVersion) && |
| 162 | (protocolVersion.v != clientVersion.v); |
| 163 | |
| 164 | |
| 165 | /* |
| 166 | * Bogus decrypted ClientKeyExchange? If so, conjure a |
| 167 | * a random preMaster secret that will fail later during |
| 168 | * Finished message processing. This is a countermeasure against |
| 169 | * the "interactive RSA PKCS#1 encryption envelop attack" reported |
| 170 | * in June 1998. Preserving the executation path will |
| 171 | * mitigate timing attacks and force consistent error handling |
| 172 | * that will prevent an attacking client from differentiating |
| 173 | * different kinds of decrypted ClientKeyExchange bogosities. |
| 174 | */ |
| 175 | if ((preMaster == null) || (preMaster.length != 48) |
| 176 | || versionMismatch) { |
| 177 | if (HandshakeMessage.debug != null && Debug.isOn("handshake")) { |
| 178 | System.out.println("Kerberos PreMasterSecret error, " |
| 179 | + "generating random secret"); |
| 180 | if (preMaster != null) { |
| 181 | Debug.println(System.out, "Invalid secret", preMaster); |
| 182 | } |
| 183 | } |
| 184 | preMaster = generatePreMaster(generator, currentVersion); |
| 185 | protocolVersion = currentVersion; |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Used by server to generate premaster secret in case of |
| 191 | * problem decoding ticket. |
| 192 | * |
| 193 | * @param protocolVersion used for preMaster[0,1] |
| 194 | * @param generator random number generator to use for generating secret. |
| 195 | */ |
| 196 | KerberosPreMasterSecret(ProtocolVersion protocolVersion, |
| 197 | SecureRandom generator) { |
| 198 | |
| 199 | this.protocolVersion = protocolVersion; |
| 200 | preMaster = generatePreMaster(generator, protocolVersion); |
| 201 | } |
| 202 | |
| 203 | private static byte[] generatePreMaster(SecureRandom rand, |
| 204 | ProtocolVersion ver) { |
| 205 | |
| 206 | byte[] pm = new byte[48]; |
| 207 | rand.nextBytes(pm); |
| 208 | pm[0] = ver.major; |
| 209 | pm[1] = ver.minor; |
| 210 | |
| 211 | return pm; |
| 212 | } |
| 213 | |
| 214 | // Clone not needed; package internal use only |
| 215 | byte[] getUnencrypted() { |
| 216 | return preMaster; |
| 217 | } |
| 218 | |
| 219 | // Clone not needed; package internal use only |
| 220 | byte[] getEncrypted() { |
| 221 | return encrypted; |
| 222 | } |
| 223 | } |