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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package sun.security.pkcs11;

import java.nio.ByteBuffer;

import java.security.*;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.MacSpi;

import sun.nio.ch.DirectBuffer;

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

MAC implementation class. This class currently supports HMAC using
MD5, SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512 and the SSL3 MAC
using MD5 and SHA-1.
Note that unlike other classes (e.g. Signature), this does not
composite various operations if the token only supports part of the
required functionality. The MAC implementations in SunJCE already
do exactly that by implementing an MAC on top of MessageDigests. We
could not do any better than they.
Author:
 Andreas Sterbenz
Since:
  1.5/**
 * MAC implementation class. This class currently supports HMAC using
 * MD5, SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512 and the SSL3 MAC
 * using MD5 and SHA-1.
 *
 * Note that unlike other classes (e.g. Signature), this does not
 * composite various operations if the token only supports part of the
 * required functionality. The MAC implementations in SunJCE already
 * do exactly that by implementing an MAC on top of MessageDigests. We
 * could not do any better than they.
 *
 * @author  Andreas Sterbenz
 * @since   1.5
 */
final class P11Mac extends MacSpi {

    // token instance
    private final Token token;

    // algorithm name
    private final String algorithm;

    // mechanism object
    private final CK_MECHANISM ckMechanism;

    // length of the MAC in bytes
    private final int macLength;

    // key instance used, if operation active
    private P11Key p11Key;

    // associated session, if any
    private Session session;

    // initialization status
    private boolean initialized;

    // one byte buffer for the update(byte) method, initialized on demand
    private byte[] oneByte;

    P11Mac(Token token, String algorithm, long mechanism)
            throws PKCS11Exception {
        super();
        this.token = token;
        this.algorithm = algorithm;
        Long params = null;
        switch ((int)mechanism) {
        case (int)CKM_MD5_HMAC:
            macLength = 16;
            break;
        case (int)CKM_SHA_1_HMAC:
            macLength = 20;
            break;
        case (int)CKM_SHA224_HMAC:
            macLength = 28;
            break;
        case (int)CKM_SHA256_HMAC:
            macLength = 32;
            break;
        case (int)CKM_SHA384_HMAC:
            macLength = 48;
            break;
        case (int)CKM_SHA512_HMAC:
            macLength = 64;
            break;
        case (int)CKM_SSL3_MD5_MAC:
            macLength = 16;
            params = Long.valueOf(16);
            break;
        case (int)CKM_SSL3_SHA1_MAC:
            macLength = 20;
            params = Long.valueOf(20);
            break;
        default:
            throw new ProviderException("Unknown mechanism: " + mechanism);
        }
        ckMechanism = new CK_MECHANISM(mechanism, params);
    }

    // reset the states to the pre-initialized values
    private void reset(boolean doCancel) {
        if (!initialized) {
            return;
        }
        initialized = false;
        try {
            if (session == null) {
                return;
            }
            if (doCancel && token.explicitCancel) {
                cancelOperation();
            }
        } finally {
            p11Key.releaseKeyID();
            session = token.releaseSession(session);
        }
    }

    private void cancelOperation() {
        token.ensureValid();
        if (session.hasObjects() == false) {
            session = token.killSession(session);
            return;
        } else {
            try {
                token.p11.C_SignFinal(session.id(), 0);
            } catch (PKCS11Exception e) {
                throw new ProviderException("Cancel failed", e);
            }
        }
    }

    private void ensureInitialized() throws PKCS11Exception {
        if (!initialized) {
            initialize();
        }
    }

    private void initialize() throws PKCS11Exception {
        if (p11Key == null) {
            throw new ProviderException(
                    "Operation cannot be performed without calling engineInit first");
        }
        token.ensureValid();
        long p11KeyID = p11Key.getKeyID();
        try {
            if (session == null) {
                session = token.getOpSession();
            }
            token.p11.C_SignInit(session.id(), ckMechanism, p11KeyID);
        } catch (PKCS11Exception e) {
            p11Key.releaseKeyID();
            session = token.releaseSession(session);
            throw e;
        }
        initialized = true;
    }

    // see JCE spec
    protected int engineGetMacLength() {
        return macLength;
    }

    // see JCE spec
    protected void engineReset() {
        reset(true);
    }

    // see JCE spec
    protected void engineInit(Key key, AlgorithmParameterSpec params)
            throws InvalidKeyException, InvalidAlgorithmParameterException {
        if (params != null) {
            throw new InvalidAlgorithmParameterException
                ("Parameters not supported");
        }
        reset(true);
        p11Key = P11SecretKeyFactory.convertKey(token, key, algorithm);
        try {
            initialize();
        } catch (PKCS11Exception e) {
            throw new InvalidKeyException("init() failed", e);
        }
    }

    // see JCE spec
    protected byte[] engineDoFinal() {
        try {
            ensureInitialized();
            return token.p11.C_SignFinal(session.id(), 0);
        } catch (PKCS11Exception e) {
            reset(true);
            throw new ProviderException("doFinal() failed", e);
        } finally {
            reset(false);
        }
    }

    // see JCE spec
    protected void engineUpdate(byte input) {
        if (oneByte == null) {
           oneByte = new byte[1];
        }
        oneByte[0] = input;
        engineUpdate(oneByte, 0, 1);
    }

    // see JCE spec
    protected void engineUpdate(byte[] b, int ofs, int len) {
        try {
            ensureInitialized();
            token.p11.C_SignUpdate(session.id(), 0, b, ofs, len);
        } catch (PKCS11Exception e) {
            throw new ProviderException("update() failed", e);
        }
    }

    // see JCE spec
    protected void engineUpdate(ByteBuffer byteBuffer) {
        try {
            ensureInitialized();
            int len = byteBuffer.remaining();
            if (len <= 0) {
                return;
            }
            if (byteBuffer instanceof DirectBuffer == false) {
                super.engineUpdate(byteBuffer);
                return;
            }
            long addr = ((DirectBuffer)byteBuffer).address();
            int ofs = byteBuffer.position();
            token.p11.C_SignUpdate(session.id(), addr + ofs, null, 0, len);
            byteBuffer.position(ofs + len);
        } catch (PKCS11Exception e) {
            throw new ProviderException("update() failed", e);
        }
    }
}