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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.security.ssl;

import java.io.IOException;

import java.security.GeneralSecurityException;

import java.security.InvalidAlgorithmParameterException;

import java.security.InvalidKeyException;

import java.security.KeyPair;

import java.security.NoSuchAlgorithmException;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.security.SecureRandom;

import java.security.interfaces.RSAPublicKey;

import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.BadPaddingException;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.net.ssl.SSLHandshakeException;

import sun.security.internal.spec.TlsRsaPremasterSecretParameterSpec;

import sun.security.util.KeyUtil;

final class RSAKeyExchange {

    static final SSLPossessionGenerator poGenerator =

            new EphemeralRSAPossessionGenerator();

    static final SSLKeyAgreementGenerator kaGenerator =

            new RSAKAGenerator();

    static final class EphemeralRSAPossession implements SSLPossession {

        // Proof of possession of the private key corresponding to the public

        // key for which a certificate is being provided for authentication.

        final RSAPublicKey        popPublicKey;

        final PrivateKey          popPrivateKey;

        EphemeralRSAPossession(PrivateKey popPrivateKey,

                RSAPublicKey popPublicKey) {

            this.popPublicKey = popPublicKey;

            this.popPrivateKey = popPrivateKey;

        }

    }

    static final class EphemeralRSACredentials implements SSLCredentials {

        final RSAPublicKey popPublicKey;

        EphemeralRSACredentials(RSAPublicKey popPublicKey) {

            this.popPublicKey = popPublicKey;

        }

    }

    private static final class EphemeralRSAPossessionGenerator

            implements SSLPossessionGenerator {

        // Prevent instantiation of this class.

        private EphemeralRSAPossessionGenerator() {

            // blank

        }

        @Override

        public SSLPossession createPossession(HandshakeContext context) {

            try {

                EphemeralKeyManager ekm =

                        context.sslContext.getEphemeralKeyManager();

                KeyPair kp = ekm.getRSAKeyPair(

                        true, context.sslContext.getSecureRandom());

                if (kp != null) {

                    return new EphemeralRSAPossession(

                            kp.getPrivate(), (RSAPublicKey)kp.getPublic());

                } else {

                    // Could not generate the ephemeral key, ignore.

                    return null;

                }

            } catch (RuntimeException rte) {

                // Could not determine keylength, ignore.

                return null;

            }

        }

    }

    static final

            class RSAPremasterSecret implements SSLPossession, SSLCredentials {

        final SecretKey premasterSecret;

        RSAPremasterSecret(SecretKey premasterSecret) {

            this.premasterSecret = premasterSecret;

        }

        byte[] getEncoded(PublicKey publicKey,

                SecureRandom secureRandom) throws GeneralSecurityException {

            Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);

            cipher.init(Cipher.WRAP_MODE, publicKey, secureRandom);

            return cipher.wrap(premasterSecret);

        }

        @SuppressWarnings("deprecation")

        static RSAPremasterSecret createPremasterSecret(

                ClientHandshakeContext chc) throws GeneralSecurityException {

            String algorithm = chc.negotiatedProtocol.useTLS12PlusSpec() ?

                    "SunTls12RsaPremasterSecret" : "SunTlsRsaPremasterSecret";

            KeyGenerator kg = JsseJce.getKeyGenerator(algorithm);

            TlsRsaPremasterSecretParameterSpec spec =

                    new TlsRsaPremasterSecretParameterSpec(

                            chc.clientHelloVersion,

                            chc.negotiatedProtocol.id);

            kg.init(spec, chc.sslContext.getSecureRandom());

            return new RSAPremasterSecret(kg.generateKey());

        }

        @SuppressWarnings("deprecation")

        static RSAPremasterSecret decode(ServerHandshakeContext shc,

                PrivateKey privateKey,

                byte[] encrypted) throws GeneralSecurityException {

            byte[] encoded = null;

            boolean needFailover = false;

            Cipher cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);

            try {

                // Try UNWRAP_MODE mode firstly.

                cipher.init(Cipher.UNWRAP_MODE, privateKey,

                        new TlsRsaPremasterSecretParameterSpec(

                                shc.clientHelloVersion,

                                shc.negotiatedProtocol.id),

                                shc.sslContext.getSecureRandom());

                // The provider selection can be delayed, please don't call

                // any Cipher method before the call to Cipher.init().

                needFailover = !KeyUtil.isOracleJCEProvider(

                        cipher.getProvider().getName());

            } catch (InvalidKeyException | UnsupportedOperationException iue) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.warning("The Cipher provider "

                            + safeProviderName(cipher)

                            + " caused exception: " + iue.getMessage());

                }

                needFailover = true;

            }

            SecretKey preMaster;

            if (needFailover) {

                // The cipher might be spoiled by unsuccessful call to init(),

                // so request a fresh instance

                cipher = JsseJce.getCipher(JsseJce.CIPHER_RSA_PKCS1);

                // Use DECRYPT_MODE and dispose the previous initialization.

                cipher.init(Cipher.DECRYPT_MODE, privateKey);

                boolean failed = false;

                try {

                    encoded = cipher.doFinal(encrypted);

                } catch (BadPaddingException bpe) {

                    // Note: encoded == null

                    failed = true;

                }

                encoded = KeyUtil.checkTlsPreMasterSecretKey(

                        shc.clientHelloVersion, shc.negotiatedProtocol.id,

                        shc.sslContext.getSecureRandom(), encoded, failed);

                preMaster = generatePremasterSecret(

                        shc.clientHelloVersion, shc.negotiatedProtocol.id,

                        encoded, shc.sslContext.getSecureRandom());

            } else {

                // the cipher should have been initialized

                preMaster = (SecretKey)cipher.unwrap(encrypted,

                        "TlsRsaPremasterSecret", Cipher.SECRET_KEY);

            }

            return new RSAPremasterSecret(preMaster);

        }

        /*

         * Retrieving the cipher's provider name for the debug purposes

         * can throw an exception by itself.

         */

        private static String safeProviderName(Cipher cipher) {

            try {

                return cipher.getProvider().toString();

            } catch (Exception e) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine("Retrieving The Cipher provider name" +

                            " caused exception ", e);

                }

            }

            try {

                return cipher.toString() + " (provider name not available)";

            } catch (Exception e) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine("Retrieving The Cipher name" +

                            " caused exception ", e);

                }

            }

            return "(cipher/provider names not available)";

        }

        // generate a premaster secret with the specified version number

        @SuppressWarnings("deprecation")

        private static SecretKey generatePremasterSecret(

                int clientVersion, int serverVersion, byte[] encodedSecret,

                SecureRandom generator) throws GeneralSecurityException {

            if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                SSLLogger.fine("Generating a premaster secret");

            }

            try {

                String s = ((clientVersion >= ProtocolVersion.TLS12.id) ?

                    "SunTls12RsaPremasterSecret" : "SunTlsRsaPremasterSecret");

                KeyGenerator kg = JsseJce.getKeyGenerator(s);

                kg.init(new TlsRsaPremasterSecretParameterSpec(

                        clientVersion, serverVersion, encodedSecret),

                        generator);

                return kg.generateKey();

            } catch (InvalidAlgorithmParameterException |

                    NoSuchAlgorithmException iae) {

                // unlikely to happen, otherwise, must be a provider exception

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine("RSA premaster secret generation error:");

                    iae.printStackTrace(System.out);

                }

                throw new GeneralSecurityException(

                        "Could not generate premaster secret", iae);

            }

        }

    }

    private static final

            class RSAKAGenerator implements SSLKeyAgreementGenerator {

        // Prevent instantiation of this class.

        private RSAKAGenerator() {

            // blank

        }

        @Override

        public SSLKeyDerivation createKeyDerivation(

                HandshakeContext context) throws IOException {

            RSAPremasterSecret premaster = null;

            if (context instanceof ClientHandshakeContext) {

                for (SSLPossession possession : context.handshakePossessions) {

                    if (possession instanceof RSAPremasterSecret) {

                        premaster = (RSAPremasterSecret)possession;

                        break;

                    }

                }

            } else {

                for (SSLCredentials credential : context.handshakeCredentials) {

                    if (credential instanceof RSAPremasterSecret) {

                        premaster = (RSAPremasterSecret)credential;

                        break;

                    }

                }

            }

            if (premaster == null) {

                context.conContext.fatal(Alert.HANDSHAKE_FAILURE,

                    "No sufficient RSA key agreement parameters negotiated");

            }

            return new RSAKAKeyDerivation(context, premaster.premasterSecret);

        }

        private static final

                class RSAKAKeyDerivation implements SSLKeyDerivation {

            private final HandshakeContext context;

            private final SecretKey preMasterSecret;

            RSAKAKeyDerivation(

                    HandshakeContext context, SecretKey preMasterSecret) {

                this.context = context;

                this.preMasterSecret = preMasterSecret;

            }

            @Override

            public SecretKey deriveKey(String algorithm,

                    AlgorithmParameterSpec params) throws IOException {

                SSLMasterKeyDerivation mskd =

                        SSLMasterKeyDerivation.valueOf(

                                context.negotiatedProtocol);

                if (mskd == null) {

                    // unlikely

                    throw new SSLHandshakeException(

                            "No expected master key derivation for protocol: " +

                            context.negotiatedProtocol.name);

                }

                SSLKeyDerivation kd = mskd.createKeyDerivation(

                        context, preMasterSecret);

                return kd.deriveKey("MasterSecret", params);

            }

        }

    }

}