/*

 * Copyright (c) 1996, 2018, 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

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

 * questions.

 */

package sun.security.ssl;

import java.io.EOFException;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

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 SSLSocket}.

 *

 * @author David Brownell

 */

final class SSLSocketInputRecord extends InputRecord implements SSLRecord {

    private InputStream is = null;

    private OutputStream os = null;

    private final byte[] temporary = new byte[1024];

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

    // Cache for incomplete handshake messages.

    private ByteBuffer handshakeBuffer = null;

    private boolean hasHeader = false;          // Had read the record header

    SSLSocketInputRecord(HandshakeHash handshakeHash) {

        super(handshakeHash, SSLReadCipher.nullTlsReadCipher());

    }

    @Override

    int bytesInCompletePacket() throws IOException {

        if (!hasHeader) {

            // read exactly one record

            try {

                int really = read(is, temporary, 0, headerSize);

                if (really < 0) {

                    // EOF: peer shut down incorrectly

                    return -1;

                }

            } catch (EOFException eofe) {

                // The caller will handle EOF.

                return -1;

            }

            hasHeader = true;

        }

        byte byteZero = temporary[0];

        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

             */

            if (!ProtocolVersion.isNegotiable(

                    temporary[1], temporary[2], false, false)) {

                throw new SSLException("Unrecognized record version " +

                        ProtocolVersion.nameOf(temporary[1], temporary[2]) +

                        " , 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 = ((temporary[3] & 0xFF) << 8) +

                   (temporary[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 && ((temporary[2] == 1) || (temporary[2] == 4))) {

                if (!ProtocolVersion.isNegotiable(

                        temporary[3], temporary[4], false, false)) {

                    throw new SSLException("Unrecognized record version " +

                            ProtocolVersion.nameOf(temporary[3], temporary[4]) +

                            " , plaintext connection?");

                }

                /*

                 * Client or Server Hello

                 */

                //

                // Short header is using here.  We reverse the code here

                // in case it is used in the future.

                //

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

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

                //        (temporary[1] & 0xFF) + (isShort ? 2 : 3);

                //

                len = ((byteZero & 0x7F) << 8) + (temporary[1] & 0xFF) + 2;

            } else {

                // Gobblygook!

                throw new SSLException(

                        "Unrecognized SSL message, plaintext connection?");

            }

        }

        return len;

    }

    // Note that the input arguments are not used actually.

    @Override

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

            int srcsLength) throws IOException, BadPaddingException {

        if (isClosed) {

            return null;

        }

        if (!hasHeader) {

            // read exactly one record

            int really = read(is, temporary, 0, headerSize);

            if (really < 0) {

                throw new EOFException("SSL peer shut down incorrectly");

            }

            hasHeader = true;

        }

        Plaintext plaintext = null;

        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.

             */

            if ((temporary[0] != ContentType.HANDSHAKE.id) &&

                (temporary[0] != ContentType.ALERT.id)) {

                hasHeader = false;

                return handleUnknownRecord(temporary);

            }

        }

        // The record header should has consumed.

        hasHeader = false;

        return decodeInputRecord(temporary);

    }

    @Override

    void setReceiverStream(InputStream inputStream) {

        this.is = inputStream;

    }

    @Override

    void setDeliverStream(OutputStream outputStream) {

        this.os = outputStream;

    }

    // Note that destination may be null

    private Plaintext[] decodeInputRecord(

            byte[] header) throws IOException, BadPaddingException {

        byte contentType = header[0];                   // pos: 0

        byte majorVersion = header[1];                  // pos: 1

        byte minorVersion = header[2];                  // pos: 2

        int contentLen = ((header[3] & 0xFF) << 8) +

                           (header[4] & 0xFF);          // 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);

        }

        //

        // Read a complete record.

        //

        ByteBuffer destination = ByteBuffer.allocate(headerSize + contentLen);

        int dstPos = destination.position();

        destination.put(temporary, 0, headerSize);

        while (contentLen > 0) {

            int howmuch = Math.min(temporary.length, contentLen);

            int really = read(is, temporary, 0, howmuch);

            if (really < 0) {

                throw new EOFException("SSL peer shut down incorrectly");

            }

            destination.put(temporary, 0, howmuch);

            contentLen -= howmuch;

        }

        destination.flip();

        destination.position(dstPos + headerSize);

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

            SSLLogger.fine(

                    "READ: " +

                    ProtocolVersion.nameOf(majorVersion, minorVersion) +

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

                    destination.remaining());

        }

        //

        // Decrypt the fragment

        //

        ByteBuffer fragment;

        try {

            Plaintext plaintext =

                    readCipher.decrypt(contentType, destination, null);

            fragment = plaintext.fragment;

            contentType = plaintext.contentType;

        } catch (BadPaddingException bpe) {

            throw bpe;

        } catch (GeneralSecurityException gse) {

            throw (SSLProtocolException)(new SSLProtocolException(

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

        }

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

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

            throw new SSLProtocolException(

        }

        //

        // 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();

                // skip the first byte: handshake type

                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;

                } 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)

                    // recordEpoch, recordSeq, plaintext);

            };

    }

    private Plaintext[] handleUnknownRecord(

            byte[] header) throws IOException, BadPaddingException {

        byte firstByte = header[0];

        byte thirdByte = header[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 = header[3];

            byte minorVersion = header[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.)

                 */

                os.write(SSLRecord.v2NoCipher);      // SSLv2Hello

                if (SSLLogger.isOn) {

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

                         SSLLogger.fine(

                                "Requested to negotiate unsupported SSLv2!");

                    }

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

                        SSLLogger.fine("Raw write", SSLRecord.v2NoCipher);

                    }

                }

                throw new SSLException("Unsupported SSL v2.0 ClientHello");

            }

            int msgLen = ((header[0] & 0x7F) << 8) | (header[1] & 0xFF);

            ByteBuffer destination = ByteBuffer.allocate(headerSize + msgLen);

            destination.put(temporary, 0, headerSize);

            msgLen -= 3;            // had read 3 bytes of content as header

            while (msgLen > 0) {

                int howmuch = Math.min(temporary.length, msgLen);

                int really = read(is, temporary, 0, howmuch);

                if (really < 0) {

                    throw new EOFException("SSL peer shut down incorrectly");

                }

                destination.put(temporary, 0, howmuch);

                msgLen -= howmuch;

            }

            destination.flip();

            /*

             * 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.

             */

            destination.position(2);     // exclude the header

            handshakeHash.receive(destination);

            destination.position(0);

            ByteBuffer converted = convertToClientHello(destination);

            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");

        }

    }

    // Read the exact bytes of data, otherwise, return -1.

    private static int read(InputStream is,

            byte[] buffer, int offset, int len) throws IOException {

        int n = 0;

        while (n < len) {

            int readLen = is.read(buffer, offset + n, len - n);

            if (readLen < 0) {

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

                    SSLLogger.fine("Raw read: EOF");

                }

                return -1;

            }

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

                ByteBuffer bb = ByteBuffer.wrap(buffer, offset + n, readLen);

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

            }

            n += readLen;

        }

        return n;

    }

}