/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.security.ssl;

import java.io.IOException;

import java.nio.ByteBuffer;

import java.security.GeneralSecurityException;

import java.util.ArrayList;

import javax.crypto.BadPaddingException;

import javax.net.ssl.SSLException;

import javax.net.ssl.SSLHandshakeException;

import javax.net.ssl.SSLProtocolException;

import sun.security.ssl.SSLCipher.SSLReadCipher;

/**

 * {@code InputRecord} implementation for {@code SSLEngine}.

 */

final class SSLEngineInputRecord extends InputRecord implements SSLRecord {

    private boolean formatVerified = false;     // SSLv2 ruled out?

    // Cache for incomplete handshake messages.

    private ByteBuffer handshakeBuffer = null;

    SSLEngineInputRecord(HandshakeHash handshakeHash) {

        super(handshakeHash, SSLReadCipher.nullTlsReadCipher());

    }

    @Override

    int estimateFragmentSize(int packetSize) {

        if (packetSize > 0) {

            return readCipher.estimateFragmentSize(packetSize, headerSize);

        } else {

            return Record.maxDataSize;

        }

    }

    @Override

    int bytesInCompletePacket(

        ByteBuffer[] srcs, int srcsOffset, int srcsLength) throws IOException {

        return bytesInCompletePacket(srcs[srcsOffset]);

    }

    private int bytesInCompletePacket(ByteBuffer packet) throws SSLException {

        /*

         * SSLv2 length field is in bytes 0/1

         * SSLv3/TLS length field is in bytes 3/4

         */

        if (packet.remaining() < 5) {

            return -1;

        }

        int pos = packet.position();

        byte byteZero = packet.get(pos);

        int len = 0;

        /*

         * If we have already verified previous packets, we can

         * ignore the verifications steps, and jump right to the

         * determination.  Otherwise, try one last heuristic to

         * see if it's SSL/TLS.

         */

        if (formatVerified ||

                (byteZero == ContentType.HANDSHAKE.id) ||

                (byteZero == ContentType.ALERT.id)) {

            /*

             * Last sanity check that it's not a wild record

             */

            byte majorVersion = packet.get(pos + 1);

            byte minorVersion = packet.get(pos + 2);

            if (!ProtocolVersion.isNegotiable(

                    majorVersion, minorVersion, false, false)) {

                throw new SSLException("Unrecognized record version " +

                        ProtocolVersion.nameOf(majorVersion, minorVersion) +

                        " , plaintext connection?");

            }

            /*

             * Reasonably sure this is a V3, disable further checks.

             * We can't do the same in the v2 check below, because

             * read still needs to parse/handle the v2 clientHello.

             */

            formatVerified = true;

            /*

             * One of the SSLv3/TLS message types.

             */

            len = ((packet.get(pos + 3) & 0xFF) << 8) +

                   (packet.get(pos + 4) & 0xFF) + headerSize;

        } else {

            /*

             * Must be SSLv2 or something unknown.

             * Check if it's short (2 bytes) or

             * long (3) header.

             *

             * Internals can warn about unsupported SSLv2

             */

            boolean isShort = ((byteZero & 0x80) != 0);

            if (isShort &&

                    ((packet.get(pos + 2) == 1) || packet.get(pos + 2) == 4)) {

                byte majorVersion = packet.get(pos + 3);

                byte minorVersion = packet.get(pos + 4);

                if (!ProtocolVersion.isNegotiable(

                        majorVersion, minorVersion, false, false)) {

                    throw new SSLException("Unrecognized record version " +

                            ProtocolVersion.nameOf(majorVersion, minorVersion) +

                            " , plaintext connection?");

                }

                /*

                 * Client or Server Hello

                 */

                int mask = (isShort ? 0x7F : 0x3F);

                len = ((byteZero & mask) << 8) +

                        (packet.get(pos + 1) & 0xFF) + (isShort ? 2 : 3);

            } else {

                // Gobblygook!

                throw new SSLException(

                        "Unrecognized SSL message, plaintext connection?");

            }

        }

        return len;

    }

    @Override

    Plaintext[] decode(ByteBuffer[] srcs, int srcsOffset,

            int srcsLength) throws IOException, BadPaddingException {

        if (srcs == null || srcs.length == 0 || srcsLength == 0) {

            return new Plaintext[0];

        } else if (srcsLength == 1) {

            return decode(srcs[srcsOffset]);

        } else {

            ByteBuffer packet = extract(srcs,

                    srcsOffset, srcsLength, SSLRecord.headerSize);

            return decode(packet);

        }

    }

    private Plaintext[] decode(ByteBuffer packet)

            throws IOException, BadPaddingException {

        if (isClosed) {

            return null;

        }

        if (SSLLogger.isOn && SSLLogger.isOn("packet")) {

            SSLLogger.fine("Raw read", packet);

        }

        // The caller should have validated the record.

        if (!formatVerified) {

            formatVerified = true;

            /*

             * The first record must either be a handshake record or an

             * alert message. If it's not, it is either invalid or an

             * SSLv2 message.

             */

            int pos = packet.position();

            byte byteZero = packet.get(pos);

            if (byteZero != ContentType.HANDSHAKE.id &&

                    byteZero != ContentType.ALERT.id) {

                return handleUnknownRecord(packet);

            }

        }

        return decodeInputRecord(packet);

    }

    private Plaintext[] decodeInputRecord(ByteBuffer packet)

            throws IOException, BadPaddingException {

        //

        // The packet should be a complete record, or more.

        //

        int srcPos = packet.position();

        int srcLim = packet.limit();

        byte contentType = packet.get();                   // pos: 0

        byte majorVersion = packet.get();                  // pos: 1

        byte minorVersion = packet.get();                  // pos: 2

        int contentLen = Record.getInt16(packet);          // pos: 3, 4

        if (SSLLogger.isOn && SSLLogger.isOn("record")) {

            SSLLogger.fine(

                    "READ: " +

                    ProtocolVersion.nameOf(majorVersion, minorVersion) +

                    " " + ContentType.nameOf(contentType) + ", length = " +

                    contentLen);

        }

        //

        // Check for upper bound.

        //

        // Note: May check packetSize limit in the future.

        if (contentLen < 0 || contentLen > maxLargeRecordSize - headerSize) {

            throw new SSLProtocolException(

                "Bad input record size, TLSCiphertext.length = " + contentLen);

        }

        //

        // Decrypt the fragment

        //

        int recLim = srcPos + SSLRecord.headerSize + contentLen;

        packet.limit(recLim);

        packet.position(srcPos + SSLRecord.headerSize);

        ByteBuffer fragment;

        try {

            Plaintext plaintext =

                    readCipher.decrypt(contentType, packet, null);

            fragment = plaintext.fragment;

            contentType = plaintext.contentType;

        } catch (BadPaddingException bpe) {

            throw bpe;

        } catch (GeneralSecurityException gse) {

            throw (SSLProtocolException)(new SSLProtocolException(

                    "Unexpected exception")).initCause(gse);

        } finally {

            // consume a complete record

            packet.limit(srcLim);

            packet.position(recLim);

        }

        //

        // check for handshake fragment

        //

        if (contentType != ContentType.HANDSHAKE.id &&

                handshakeBuffer != null && handshakeBuffer.hasRemaining()) {

            throw new SSLProtocolException(

                    "Expecting a handshake fragment, but received " +

                    ContentType.nameOf(contentType));

        }

        //

        // parse handshake messages

        //

        if (contentType == ContentType.HANDSHAKE.id) {

            ByteBuffer handshakeFrag = fragment;

            if ((handshakeBuffer != null) &&

                    (handshakeBuffer.remaining() != 0)) {

                ByteBuffer bb = ByteBuffer.wrap(new byte[

                        handshakeBuffer.remaining() + fragment.remaining()]);

                bb.put(handshakeBuffer);

                bb.put(fragment);

                handshakeFrag = bb.rewind();

                handshakeBuffer = null;

            }

            ArrayList<Plaintext> plaintexts = new ArrayList<>(5);

            while (handshakeFrag.hasRemaining()) {

                int remaining = handshakeFrag.remaining();

                if (remaining < handshakeHeaderSize) {

                    handshakeBuffer = ByteBuffer.wrap(new byte[remaining]);

                    handshakeBuffer.put(handshakeFrag);

                    handshakeBuffer.rewind();

                    break;

                }

                handshakeFrag.mark();

                byte handshakeType = handshakeFrag.get();

                int handshakeBodyLen = Record.getInt24(handshakeFrag);

                handshakeFrag.reset();

                int handshakeMessageLen =

                        handshakeHeaderSize + handshakeBodyLen;

                if (remaining < handshakeMessageLen) {

                    handshakeBuffer = ByteBuffer.wrap(new byte[remaining]);

                    handshakeBuffer.put(handshakeFrag);

                    handshakeBuffer.rewind();

                    break;

                } else if (remaining == handshakeMessageLen) {

                    if (handshakeHash.isHashable(handshakeType)) {

                        handshakeHash.receive(handshakeFrag);

                    }

                    plaintexts.add(

                        new Plaintext(contentType,

                            majorVersion, minorVersion, -1, -1L, handshakeFrag)

                    );

                    break;

                } else {

                    int fragPos = handshakeFrag.position();

                    int fragLim = handshakeFrag.limit();

                    int nextPos = fragPos + handshakeMessageLen;

                    handshakeFrag.limit(nextPos);

                    if (handshakeHash.isHashable(handshakeType)) {

                        handshakeHash.receive(handshakeFrag);

                    }

                    plaintexts.add(

                        new Plaintext(contentType, majorVersion, minorVersion,

                            -1, -1L, handshakeFrag.slice())

                    );

                    handshakeFrag.position(nextPos);

                    handshakeFrag.limit(fragLim);

                }

            }

            return plaintexts.toArray(new Plaintext[0]);

        }

        return new Plaintext[] {

            new Plaintext(contentType,

                majorVersion, minorVersion, -1, -1L, fragment)

        };

    }

    private Plaintext[] handleUnknownRecord(ByteBuffer packet)

            throws IOException, BadPaddingException {

        //

        // The packet should be a complete record.

        //

        int srcPos = packet.position();

        int srcLim = packet.limit();

        byte firstByte = packet.get(srcPos);

        byte thirdByte = packet.get(srcPos + 2);

        // Does it look like a Version 2 client hello (V2ClientHello)?

        if (((firstByte & 0x80) != 0) && (thirdByte == 1)) {

            /*

             * If SSLv2Hello is not enabled, throw an exception.

             */

            if (helloVersion != ProtocolVersion.SSL20Hello) {

                throw new SSLHandshakeException("SSLv2Hello is not enabled");

            }

            byte majorVersion = packet.get(srcPos + 3);

            byte minorVersion = packet.get(srcPos + 4);

            if ((majorVersion == ProtocolVersion.SSL20Hello.major) &&

                (minorVersion == ProtocolVersion.SSL20Hello.minor)) {

                /*

                 * Looks like a V2 client hello, but not one saying

                 * "let's talk SSLv3".  So we need to send an SSLv2

                 * error message, one that's treated as fatal by

                 * clients (Otherwise we'll hang.)

                 */

                if (SSLLogger.isOn && SSLLogger.isOn("record")) {

                   SSLLogger.fine(

                            "Requested to negotiate unsupported SSLv2!");

                }

                // hack code, the exception is caught in SSLEngineImpl

                // so that SSLv2 error message can be delivered properly.

                throw new UnsupportedOperationException(        // SSLv2Hello

                        "Unsupported SSL v2.0 ClientHello");

            }

            /*

             * If we can map this into a V3 ClientHello, read and

             * hash the rest of the V2 handshake, turn it into a

             * V3 ClientHello message, and pass it up.

             */

            packet.position(srcPos + 2);        // exclude the header

            handshakeHash.receive(packet);

            packet.position(srcPos);

            ByteBuffer converted = convertToClientHello(packet);

            if (SSLLogger.isOn && SSLLogger.isOn("packet")) {

                SSLLogger.fine(

                        "[Converted] ClientHello", converted);

            }

            return new Plaintext[] {

                    new Plaintext(ContentType.HANDSHAKE.id,

                    majorVersion, minorVersion, -1, -1L, converted)

                };

        } else {

            if (((firstByte & 0x80) != 0) && (thirdByte == 4)) {

                throw new SSLException("SSL V2.0 servers are not supported.");

            }

            throw new SSLException("Unsupported or unrecognized SSL message");

        }

    }

}