/*
* Copyright 1996-2007 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package sun.security.ssl;
import java.io.*;
import java.security.*;
import java.security.interfaces.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.net.ssl.*;
import sun.security.internal.spec.TlsRsaPremasterSecretParameterSpec;
/**
* This is the client key exchange message (CLIENT --> SERVER) used with
* all RSA key exchanges; it holds the RSA-encrypted pre-master secret.
*
* The message is encrypted using PKCS #1 block type 02 encryption with the
* server's public key. The padding and resulting message size is a function
* of this server's public key modulus size, but the pre-master secret is
* always exactly 48 bytes.
*
*/
final class RSAClientKeyExchange extends HandshakeMessage {
/**
* The TLS spec says that the version in the RSA premaster secret must
* be the maximum version supported by the client (i.e. the version it
* requested in its client hello version). However, we (and other
* implementations) used to send the active negotiated version. The
* system property below allows to toggle the behavior.
*
* Default is "false" (old behavior) for compatibility reasons. This
* will be changed in the future.
*/
private final static String PROP_NAME =
"com.sun.net.ssl.rsaPreMasterSecretFix";
private final static boolean rsaPreMasterSecretFix =
Debug.getBooleanProperty(PROP_NAME, false);
int messageType() {
return ht_client_key_exchange;
}
/*
* The following field values were encrypted with the server's public
* key (or temp key from server key exchange msg) and are presented
* here in DECRYPTED form.
*/
private ProtocolVersion protocolVersion; // preMaster [0,1]
SecretKey preMaster;
private byte[] encrypted; // same size as public modulus
/*
* Client randomly creates a pre-master secret and encrypts it
* using the server's RSA public key; only the server can decrypt
* it, using its RSA private key. Result is the same size as the
* server's public key, and uses PKCS #1 block format 02.
*/
RSAClientKeyExchange(ProtocolVersion protocolVersion, ProtocolVersion maxVersion,
SecureRandom generator, PublicKey publicKey) throws IOException {
if (publicKey.getAlgorithm().equals("RSA") == false) {
throw new SSLKeyException("Public key not of type RSA");
}
this.protocolVersion = protocolVersion;
int major, minor;
if (rsaPreMasterSecretFix) {
major = maxVersion.major;
minor = maxVersion.minor;
} else {
major = protocolVersion.major;
minor = protocolVersion.minor;
}
try {
KeyGenerator kg = JsseJce.getKeyGenerator("SunTlsRsaPremasterSecret");
kg.init(new TlsRsaPremasterSecretParameterSpec(major, minor));
preMaster = kg.generateKey();
Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);
cipher.init(Cipher.WRAP_MODE, publicKey, generator);
encrypted = cipher.wrap(preMaster);
} catch (GeneralSecurityException e) {
throw (SSLKeyException)new SSLKeyException
("RSA premaster secret error").initCause(e);
}
}
/*
* Server gets the PKCS #1 (block format 02) data, decrypts
* it with its private key.
*/
RSAClientKeyExchange(ProtocolVersion currentVersion, HandshakeInStream input,
int messageSize, PrivateKey privateKey) throws IOException {
if (privateKey.getAlgorithm().equals("RSA") == false) {
throw new SSLKeyException("Private key not of type RSA");
}
this.protocolVersion = currentVersion;
if (currentVersion.v >= ProtocolVersion.TLS10.v) {
encrypted = input.getBytes16();
} else {
encrypted = new byte [messageSize];
if (input.read(encrypted) != messageSize) {
throw new SSLProtocolException
("SSL: read PreMasterSecret: short read");
}
}
try {
Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);
cipher.init(Cipher.UNWRAP_MODE, privateKey);
preMaster = (SecretKey)cipher.unwrap(encrypted,
"TlsRsaPremasterSecret", Cipher.SECRET_KEY);
} catch (Exception e) {
/*
* Bogus decrypted ClientKeyExchange? If so, conjure a
* a random preMaster secret that will fail later during
* Finished message processing. This is a countermeasure against
* the "interactive RSA PKCS#1 encryption envelop attack" reported
* in June 1998. Preserving the executation path will
* mitigate timing attacks and force consistent error handling
* that will prevent an attacking client from differentiating
* different kinds of decrypted ClientKeyExchange bogosities.
*/
if (debug != null && Debug.isOn("handshake")) {
System.out.println("Error decrypting premaster secret:");
e.printStackTrace(System.out);
System.out.println("Generating random secret");
}
preMaster = generateDummySecret(currentVersion);
}
}
// generate a premaster secret with the specified version number
static SecretKey generateDummySecret(ProtocolVersion version) {
try {
KeyGenerator kg =
JsseJce.getKeyGenerator("SunTlsRsaPremasterSecret");
kg.init(new TlsRsaPremasterSecretParameterSpec
(version.major, version.minor));
return kg.generateKey();
} catch (GeneralSecurityException e) {
throw new RuntimeException("Could not generate dummy secret", e);
}
}
int messageLength() {
if (protocolVersion.v >= ProtocolVersion.TLS10.v) {
return encrypted.length + 2;
} else {
return encrypted.length;
}
}
void send(HandshakeOutStream s) throws IOException {
if (protocolVersion.v >= ProtocolVersion.TLS10.v) {
s.putBytes16(encrypted);
} else {
s.write(encrypted);
}
}
void print(PrintStream s) throws IOException {
s.println("*** ClientKeyExchange, RSA PreMasterSecret, " + protocolVersion);
}
}