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 * published by the Free Software Foundation.  Oracle designates this

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 * by Oracle in the LICENSE file that accompanied this code.

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 * This code is distributed in the hope that it will be useful, but WITHOUT

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 * 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

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package sun.security.pkcs11;

import java.security.*;

import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.*;

import javax.crypto.spec.*;

import sun.security.internal.spec.TlsPrfParameterSpec;

import static sun.security.pkcs11.TemplateManager.*;

import sun.security.pkcs11.wrapper.*;

import static sun.security.pkcs11.wrapper.PKCS11Constants.*;

/**

 * KeyGenerator for the TLS PRF. Note that although the PRF is used in a number

 * of places during the handshake, this class is usually only used to calculate

 * the Finished messages. The reason is that for those other uses more specific

 * PKCS#11 mechanisms have been defined (CKM_SSL3_MASTER_KEY_DERIVE, etc.).

 *

 * <p>This class supports the CKM_TLS_PRF mechanism from PKCS#11 v2.20 and

 * the older NSS private mechanism.

 *

 * @author  Andreas Sterbenz

 * @since   1.6

 */

final class P11TlsPrfGenerator extends KeyGeneratorSpi {

    private final static String MSG =

            "TlsPrfGenerator must be initialized using a TlsPrfParameterSpec";

    // token instance

    private final Token token;

    // algorithm name

    private final String algorithm;

    // mechanism id

    private final long mechanism;

    private TlsPrfParameterSpec spec;

    private P11Key p11Key;

    P11TlsPrfGenerator(Token token, String algorithm, long mechanism)

            throws PKCS11Exception {

        super();

        this.token = token;

        this.algorithm = algorithm;

        this.mechanism = mechanism;

    }

    protected void engineInit(SecureRandom random) {

        throw new InvalidParameterException(MSG);

    }

    protected void engineInit(AlgorithmParameterSpec params,

            SecureRandom random) throws InvalidAlgorithmParameterException {

        if (params instanceof TlsPrfParameterSpec == false) {

            throw new InvalidAlgorithmParameterException(MSG);

        }

        this.spec = (TlsPrfParameterSpec)params;

        SecretKey key = spec.getSecret();

        if (key == null) {

            key = NULL_KEY;

        }

        try {

            p11Key = P11SecretKeyFactory.convertKey(token, key, null);

        } catch (InvalidKeyException e) {

            throw new InvalidAlgorithmParameterException("init() failed", e);

        }

    }

    // SecretKeySpec does not allow zero length keys, so we define our own class.

    private static final SecretKey NULL_KEY = new SecretKey() {

        public byte[] getEncoded() {

            return new byte[0];

        }

        public String getFormat() {

            return "RAW";

        }

        public String getAlgorithm() {

            return "Generic";

        }

    };

    protected void engineInit(int keysize, SecureRandom random) {

        throw new InvalidParameterException(MSG);

    }

    protected SecretKey engineGenerateKey() {

        if (spec == null) {

            throw new IllegalStateException("TlsPrfGenerator must be initialized");

        }

        byte[] label = P11Util.getBytesUTF8(spec.getLabel());

        byte[] seed = spec.getSeed();

        if (mechanism == CKM_NSS_TLS_PRF_GENERAL) {

            Session session = null;

            try {

                session = token.getOpSession();

                token.p11.C_SignInit

                    (session.id(), new CK_MECHANISM(mechanism), p11Key.keyID);

                token.p11.C_SignUpdate(session.id(), 0, label, 0, label.length);

                token.p11.C_SignUpdate(session.id(), 0, seed, 0, seed.length);

                byte[] out = token.p11.C_SignFinal

                                    (session.id(), spec.getOutputLength());

                return new SecretKeySpec(out, "TlsPrf");

            } catch (PKCS11Exception e) {

                throw new ProviderException("Could not calculate PRF", e);

            } finally {

                token.releaseSession(session);

            }

        }

        // mechanism == CKM_TLS_PRF

        byte[] out = new byte[spec.getOutputLength()];

        CK_TLS_PRF_PARAMS params = new CK_TLS_PRF_PARAMS(seed, label, out);

        Session session = null;

        try {

            session = token.getOpSession();

            long keyID = token.p11.C_DeriveKey(session.id(),

                new CK_MECHANISM(mechanism, params), p11Key.keyID, null);

            // ignore keyID, returned PRF bytes are in 'out'

            return new SecretKeySpec(out, "TlsPrf");

        } catch (PKCS11Exception e) {

            throw new ProviderException("Could not calculate PRF", e);

        } finally {

            token.releaseSession(session);

        }

    }

}