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 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. 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.  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.pkcs11;

import java.util.*;

import java.nio.ByteBuffer;

import java.security.*;

import javax.crypto.SecretKey;

import sun.nio.ch.DirectBuffer;

import sun.security.pkcs11.wrapper.*;

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

/**

 * MessageDigest implementation class. This class currently supports

 * MD2, MD5, SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512.

 *

 * Note that many digest operations are on fairly small amounts of data

 * (less than 100 bytes total). For example, the 2nd hashing in HMAC or

 * the PRF in TLS. In order to speed those up, we use some buffering to

 * minimize number of the Java->native transitions.

 *

 * @author  Andreas Sterbenz

 * @since   1.5

 */

final class P11Digest extends MessageDigestSpi implements Cloneable {

    /* fields initialized, no session acquired */

    private final static int S_BLANK    = 1;

    /* data in buffer, session acquired, but digest not initialized */

    private final static int S_BUFFERED = 2;

    /* session initialized for digesting */

    private final static int S_INIT     = 3;

    private final static int BUFFER_SIZE = 96;

    // token instance

    private final Token token;

    // algorithm name

    private final String algorithm;

    // mechanism id object

    private final CK_MECHANISM mechanism;

    // length of the digest in bytes

    private final int digestLength;

    // associated session, if any

    private Session session;

    // current state, one of S_* above

    private int state;

    // buffer to reduce number of JNI calls

    private byte[] buffer;

    // offset into the buffer

    private int bufOfs;

    P11Digest(Token token, String algorithm, long mechanism) {

        super();

        this.token = token;

        this.algorithm = algorithm;

        this.mechanism = new CK_MECHANISM(mechanism);

        switch ((int)mechanism) {

        case (int)CKM_MD2:

        case (int)CKM_MD5:

            digestLength = 16;

            break;

        case (int)CKM_SHA_1:

            digestLength = 20;

            break;

        case (int)CKM_SHA224:

            digestLength = 28;

            break;

        case (int)CKM_SHA256:

            digestLength = 32;

            break;

        case (int)CKM_SHA384:

            digestLength = 48;

            break;

        case (int)CKM_SHA512:

            digestLength = 64;

            break;

        default:

            throw new ProviderException("Unknown mechanism: " + mechanism);

        }

        buffer = new byte[BUFFER_SIZE];

        state = S_BLANK;

    }

    // see JCA spec

    protected int engineGetDigestLength() {

        return digestLength;

    }

    private void fetchSession() {

        token.ensureValid();

        if (state == S_BLANK) {

            try {

                session = token.getOpSession();

                state = S_BUFFERED;

            } catch (PKCS11Exception e) {

                throw new ProviderException("No more session available", e);

            }

        }

    }

    // see JCA spec

    protected void engineReset() {

        token.ensureValid();

        if (session != null) {

            if (state == S_INIT && token.explicitCancel == true) {

                session = token.killSession(session);

            } else {

                session = token.releaseSession(session);

            }

        }

        state = S_BLANK;

        bufOfs = 0;

    }

    // see JCA spec

    protected byte[] engineDigest() {

        try {

            byte[] digest = new byte[digestLength];

            int n = engineDigest(digest, 0, digestLength);

            return digest;

        } catch (DigestException e) {

            throw new ProviderException("internal error", e);

        }

    }

    // see JCA spec

    protected int engineDigest(byte[] digest, int ofs, int len)

            throws DigestException {

        if (len < digestLength) {

            throw new DigestException("Length must be at least " +

                    digestLength);

        }

        fetchSession();

        try {

            int n;

            if (state == S_BUFFERED) {

                n = token.p11.C_DigestSingle(session.id(), mechanism, buffer, 0,

                        bufOfs, digest, ofs, len);

                bufOfs = 0;

            } else {

                if (bufOfs != 0) {

                    token.p11.C_DigestUpdate(session.id(), 0, buffer, 0,

                            bufOfs);

                    bufOfs = 0;

                }

                n = token.p11.C_DigestFinal(session.id(), digest, ofs, len);

            }

            if (n != digestLength) {

                throw new ProviderException("internal digest length error");

            }

            return n;

        } catch (PKCS11Exception e) {

            throw new ProviderException("digest() failed", e);

        } finally {

            engineReset();

        }

    }

    // see JCA spec

    protected void engineUpdate(byte in) {

        byte[] temp = { in };

        engineUpdate(temp, 0, 1);

    }

    // see JCA spec

    protected void engineUpdate(byte[] in, int ofs, int len) {

        if (len <= 0) {

            return;

        }

        fetchSession();

        try {

            if (state == S_BUFFERED) {

                token.p11.C_DigestInit(session.id(), mechanism);

                state = S_INIT;

            }

            if ((bufOfs != 0) && (bufOfs + len > buffer.length)) {

                // process the buffered data

                token.p11.C_DigestUpdate(session.id(), 0, buffer, 0, bufOfs);

                bufOfs = 0;

            }

            if (bufOfs + len > buffer.length) {

                // process the new data

                token.p11.C_DigestUpdate(session.id(), 0, in, ofs, len);

             } else {

                // buffer the new data

                System.arraycopy(in, ofs, buffer, bufOfs, len);

                bufOfs += len;

            }

        } catch (PKCS11Exception e) {

            engineReset();

            throw new ProviderException("update() failed", e);

        }

    }

    // Called by SunJSSE via reflection during the SSL 3.0 handshake if

    // the master secret is sensitive. We may want to consider making this

    // method public in a future release.

    protected void implUpdate(SecretKey key) throws InvalidKeyException {

        // SunJSSE calls this method only if the key does not have a RAW

        // encoding, i.e. if it is sensitive. Therefore, no point in calling

        // SecretKeyFactory to try to convert it. Just verify it ourselves.

        if (key instanceof P11Key == false) {

            throw new InvalidKeyException("Not a P11Key: " + key);

        }

        P11Key p11Key = (P11Key)key;

        if (p11Key.token != token) {

            throw new InvalidKeyException("Not a P11Key of this provider: " +

                    key);

        }

        fetchSession();

        try {

            if (state == S_BUFFERED) {

                token.p11.C_DigestInit(session.id(), mechanism);

                state = S_INIT;

            }

            if (bufOfs != 0) {

                token.p11.C_DigestUpdate(session.id(), 0, buffer, 0, bufOfs);

                bufOfs = 0;

            }

            token.p11.C_DigestKey(session.id(), p11Key.keyID);

        } catch (PKCS11Exception e) {

            engineReset();

            throw new ProviderException("update(SecretKey) failed", e);

        }

    }

    // see JCA spec

    protected void engineUpdate(ByteBuffer byteBuffer) {

        int len = byteBuffer.remaining();

        if (len <= 0) {

            return;

        }

        if (byteBuffer instanceof DirectBuffer == false) {

            super.engineUpdate(byteBuffer);

            return;

        }

        fetchSession();

        long addr = ((DirectBuffer)byteBuffer).address();

        int ofs = byteBuffer.position();

        try {

            if (state == S_BUFFERED) {

                token.p11.C_DigestInit(session.id(), mechanism);

                state = S_INIT;

            }

            if (bufOfs != 0) {

                token.p11.C_DigestUpdate(session.id(), 0, buffer, 0, bufOfs);

                bufOfs = 0;

            }

            token.p11.C_DigestUpdate(session.id(), addr + ofs, null, 0, len);

            byteBuffer.position(ofs + len);

        } catch (PKCS11Exception e) {

            engineReset();

            throw new ProviderException("update() failed", e);

        }

    }

    public Object clone() throws CloneNotSupportedException {

        P11Digest copy = (P11Digest) super.clone();

        copy.buffer = buffer.clone();

        try {

            if (session != null) {

                copy.session = copy.token.getOpSession();

            }

            if (state == S_INIT) {

                byte[] stateValues =

                    token.p11.C_GetOperationState(session.id());

                token.p11.C_SetOperationState(copy.session.id(),

                                              stateValues, 0, 0);

            }

        } catch (PKCS11Exception e) {

            throw (CloneNotSupportedException)

                (new CloneNotSupportedException(algorithm).initCause(e));

        }

        return copy;

    }

}