/*

 * Copyright (c) 1996, 2014, 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.*;

import java.nio.*;

import java.util.*;

import javax.crypto.BadPaddingException;

import javax.net.ssl.*;

import sun.security.util.HexDumpEncoder;

/**

 * {@code InputRecord} takes care of the management of SSL/TLS/DTLS input

 * records, including buffering, decryption, handshake messages marshal, etc.

 *

 * @author David Brownell

 */

class InputRecord implements Record, Closeable {

    /* Class and subclass dynamic debugging support */

    static final Debug debug = Debug.getInstance("ssl");

    Authenticator       readAuthenticator;

    CipherBox           readCipher;

    HandshakeHash       handshakeHash;

    boolean             isClosed;

    // The ClientHello version to accept. If set to ProtocolVersion.SSL20Hello

    // and the first message we read is a ClientHello in V2 format, we convert

    // it to V3. Otherwise we throw an exception when encountering a V2 hello.

    ProtocolVersion     helloVersion;

    // fragment size

    int                 fragmentSize;

    InputRecord() {

        this.readCipher = CipherBox.NULL;

        this.readAuthenticator = null;      // Please override this assignment.

        this.helloVersion = ProtocolVersion.DEFAULT_HELLO;

        this.fragmentSize = Record.maxDataSize;

    }

    void setHelloVersion(ProtocolVersion helloVersion) {

        this.helloVersion = helloVersion;

    }

    ProtocolVersion getHelloVersion() {

        return helloVersion;

    }

    /*

     * Set instance for the computation of handshake hashes.

     *

     * For handshaking, we need to be able to hash every byte above the

     * record marking layer.  This is where we're guaranteed to see those

     * bytes, so this is where we can hash them ... especially in the

     * case of hashing the initial V2 message!

     */

    void setHandshakeHash(HandshakeHash handshakeHash) {

        if (handshakeHash != null) {

            byte[] reserved = null;

            if (this.handshakeHash != null) {

                reserved = this.handshakeHash.getAllHandshakeMessages();

            }

            if ((reserved != null) && (reserved.length != 0)) {

                handshakeHash.update(reserved, 0, reserved.length);

               if (debug != null && Debug.isOn("data")) {

                    Debug.printHex(

                        "[reserved] handshake hash: len = " + reserved.length,

                        reserved);

               }

            }

        }

        this.handshakeHash = handshakeHash;

    }

    boolean seqNumIsHuge() {

        return (readAuthenticator != null) &&

                        readAuthenticator.seqNumIsHuge();

    }

    boolean isEmpty() {

        return false;

    }

    // apply to DTLS SSLEngine

    void expectingFinishFlight() {

        // blank

    }

    /**

     * Prevent any more data from being read into this record,

     * and flag the record as holding no data.

     */

    @Override

    public synchronized void close() throws IOException {

        if (!isClosed) {

            isClosed = true;

            readCipher.dispose();

        }

    }

    // apply to SSLSocket and SSLEngine

    void changeReadCiphers(

            Authenticator readAuthenticator, CipherBox readCipher) {

        /*

         * Dispose of any intermediate state in the underlying cipher.

         * For PKCS11 ciphers, this will release any attached sessions,

         * and thus make finalization faster.

         *

         * Since MAC's doFinal() is called for every SSL/TLS packet, it's

         * not necessary to do the same with MAC's.

         */

        readCipher.dispose();

        this.readAuthenticator = readAuthenticator;

        this.readCipher = readCipher;

    }

    // change fragment size

    void changeFragmentSize(int fragmentSize) {

        this.fragmentSize = fragmentSize;

    }

    /*

     * Check if there is enough inbound data in the ByteBuffer to make

     * a inbound packet.

     *

     * @return -1 if there are not enough bytes to tell (small header),

     */

    // apply to SSLEngine only

    int bytesInCompletePacket(ByteBuffer buf) throws SSLException {

        throw new UnsupportedOperationException();

    }

    // apply to SSLSocket only

    int bytesInCompletePacket(InputStream is) throws IOException {

        throw new UnsupportedOperationException();

    }

    /**

     * Return true if the specified record protocol version is out of the

     * range of the possible supported versions.

     */

    void checkRecordVersion(ProtocolVersion version,

            boolean allowSSL20Hello) throws SSLException {

        // blank

    }

    // apply to DTLS SSLEngine only

    Plaintext acquirePlaintext()

            throws IOException, BadPaddingException {

        throw new UnsupportedOperationException();

    }

    // read, decrypt and decompress the network record.

    //

    // apply to SSLEngine only

    Plaintext decode(ByteBuffer netData)

            throws IOException, BadPaddingException {

        throw new UnsupportedOperationException();

    }

    // apply to SSLSocket only

    Plaintext decode(InputStream is, ByteBuffer destination)

            throws IOException, BadPaddingException {

        throw new UnsupportedOperationException();

    }

    // apply to SSLSocket only

    void setDeliverStream(OutputStream outputStream) {

        throw new UnsupportedOperationException();

    }

    // calculate plaintext fragment size

    //

    // apply to SSLEngine only

    int estimateFragmentSize(int packetSize) {

        throw new UnsupportedOperationException();

    }

    //

    // shared helpers

    //

    // Not apply to DTLS

    static ByteBuffer convertToClientHello(ByteBuffer packet) {

        int srcPos = packet.position();

        int srcLim = packet.limit();

        byte firstByte = packet.get();

        byte secondByte = packet.get();

        int recordLen = (((firstByte & 0x7F) << 8) | (secondByte & 0xFF)) + 2;

        packet.position(srcPos + 3);        // the V2ClientHello record header

        byte majorVersion = packet.get();

        byte minorVersion = packet.get();

        int cipherSpecLen = ((packet.get() & 0xFF) << 8) +

                             (packet.get() & 0xFF);

        int sessionIdLen  = ((packet.get() & 0xFF) << 8) +

                             (packet.get() & 0xFF);

        int nonceLen      = ((packet.get() & 0xFF) << 8) +

                             (packet.get() & 0xFF);

        // Required space for the target SSLv3 ClientHello message.

        //  5: record header size

        //  4: handshake header size

        //  2: ClientHello.client_version

        // 32: ClientHello.random

        //  1: length byte of ClientHello.session_id

        //  2: length bytes of ClientHello.cipher_suites

        //  2: empty ClientHello.compression_methods

        int requiredSize = 48 + sessionIdLen + ((cipherSpecLen * 2 ) / 3 );

        byte[] converted = new byte[requiredSize];

        /*

         * Build the first part of the V3 record header from the V2 one

         * that's now buffered up.  (Lengths are fixed up later).

         */

        // Note: need not to set the header actually.

        converted[0] = ct_handshake;

        converted[1] = majorVersion;

        converted[2] = minorVersion;

        // header [3..4] for handshake message length

        // required size is 5;

        /*

         * Store the generic V3 handshake header:  4 bytes

         */

        converted[5] = 1;    // HandshakeMessage.ht_client_hello

        // buf [6..8] for length of ClientHello (int24)

        // required size += 4;

        /*

         * ClientHello header starts with SSL version

         */

        converted[9] = majorVersion;

        converted[10] = minorVersion;

        // required size += 2;

        int pointer = 11;

        /*

         * Copy Random value/nonce ... if less than the 32 bytes of

         * a V3 "Random", right justify and zero pad to the left.  Else

         * just take the last 32 bytes.

         */

        int offset = srcPos + 11 + cipherSpecLen + sessionIdLen;

        if (nonceLen < 32) {

            for (int i = 0; i < (32 - nonceLen); i++) {

                converted[pointer++] = 0;

            }

            packet.position(offset);

            packet.get(converted, pointer, nonceLen);

            pointer += nonceLen;

        } else {

            packet.position(offset + nonceLen - 32);

            packet.get(converted, pointer, 32);

            pointer += 32;

        }

        /*

         * Copy session ID (only one byte length!)

         */

        offset -= sessionIdLen;

        converted[pointer++] = (byte)(sessionIdLen & 0xFF);

        packet.position(offset);

        packet.get(converted, pointer, sessionIdLen);

        /*

         * Copy and translate cipher suites ... V2 specs with first byte zero

         * are really V3 specs (in the last 2 bytes), just copy those and drop

         * the other ones.  Preference order remains unchanged.

         *

         * Example:  Netscape Navigator 3.0 (exportable) says:

         *

         * 0/3,     SSL_RSA_EXPORT_WITH_RC4_40_MD5

         * 0/6,     SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5

         *

         * Microsoft Internet Explorer 3.0 (exportable) supports only

         *

         * 0/3,     SSL_RSA_EXPORT_WITH_RC4_40_MD5

         */

        int j;

        offset -= cipherSpecLen;

        packet.position(offset);

        j = pointer + 2;

        for (int i = 0; i < cipherSpecLen; i += 3) {

            if (packet.get() != 0) {

                // Ignore version 2.0 specifix cipher suite.  Clients

                // should also include the version 3.0 equivalent in

                // the V2ClientHello message.

                packet.get();           // ignore the 2nd byte

                packet.get();           // ignore the 3rd byte

                continue;

            }

            converted[j++] = packet.get();

            converted[j++] = packet.get();

        }

        j -= pointer + 2;

        converted[pointer++] = (byte)((j >>> 8) & 0xFF);

        converted[pointer++] = (byte)(j & 0xFF);

        pointer += j;

        /*

         * Append compression methods (default/null only)

         */

        converted[pointer++] = 1;

        converted[pointer++] = 0;      // Session.compression_null

        /*

         * Fill in lengths of the messages we synthesized (nested:

         * V3 handshake message within V3 record).

         */

        // Note: need not to set the header actually.

        int fragLen = pointer - 5;                      // TLSPlaintext.length

        converted[3] = (byte)((fragLen >>> 8) & 0xFF);

        converted[4] = (byte)(fragLen & 0xFF);

        /*

         * Handshake.length, length of ClientHello message

         */

        fragLen = pointer - 9;                          // Handshake.length

        converted[6] = (byte)((fragLen >>> 16) & 0xFF);

        converted[7] = (byte)((fragLen >>> 8) & 0xFF);

        converted[8] = (byte)(fragLen & 0xFF);

        // consume the full record

        packet.position(srcPos + recordLen);

        // Need no header bytes.

        return ByteBuffer.wrap(converted, 5, pointer - 5);  // 5: header size

    }

    static ByteBuffer decrypt(Authenticator authenticator, CipherBox box,

            byte contentType, ByteBuffer bb) throws BadPaddingException {

        return decrypt(authenticator, box, contentType, bb, null);

    }

    static ByteBuffer decrypt(Authenticator authenticator,

            CipherBox box, byte contentType, ByteBuffer bb,

            byte[] sequence) throws BadPaddingException {

        BadPaddingException reservedBPE = null;

        int tagLen =

            (authenticator instanceof MAC) ? ((MAC)authenticator).MAClen() : 0;

        int cipheredLength = bb.remaining();

        int srcPos = bb.position();

        if (!box.isNullCipher()) {

            try {

                // apply explicit nonce for AEAD/CBC cipher suites if needed

                int nonceSize = box.applyExplicitNonce(

                        authenticator, contentType, bb, sequence);

                // decrypt the content

                if (box.isAEADMode()) {

                    // DON'T decrypt the nonce_explicit for AEAD mode

                    bb.position(srcPos + nonceSize);

                }   // The explicit IV for CBC mode can be decrypted.

                // Note that the CipherBox.decrypt() does not change

                // the capacity of the buffer.

                box.decrypt(bb, tagLen);

                // We don't actually remove the nonce.

                bb.position(srcPos + nonceSize);

            } catch (BadPaddingException bpe) {

                // RFC 2246 states that decryption_failed should be used

                // for this purpose. However, that allows certain attacks,

                // so we just send bad record MAC. We also need to make

                // sure to always check the MAC to avoid a timing attack

                // for the same issue. See paper by Vaudenay et al and the

                // update in RFC 4346/5246.

                //

                // Failover to message authentication code checking.

                reservedBPE = bpe;

            }

        }

        // Requires message authentication code for null, stream and block

        // cipher suites.

        if ((authenticator instanceof MAC) && (tagLen != 0)) {

            MAC signer = (MAC)authenticator;

            int contentLen = bb.remaining() - tagLen;

            // Note that although it is not necessary, we run the same MAC

            // computation and comparison on the payload for both stream

            // cipher and CBC block cipher.

            if (contentLen < 0) {

                // negative data length, something is wrong

                if (reservedBPE == null) {

                    reservedBPE = new BadPaddingException("bad record");

                }

                // set offset of the dummy MAC

                contentLen = cipheredLength - tagLen;

                bb.limit(srcPos + cipheredLength);

            }

            // Run MAC computation and comparison on the payload.

            //

            // MAC data would be stripped off during the check.

            if (checkMacTags(contentType, bb, signer, sequence, false)) {

                if (reservedBPE == null) {

                    reservedBPE = new BadPaddingException("bad record MAC");

                }

            }

            // Run MAC computation and comparison on the remainder.

            //

            // It is only necessary for CBC block cipher.  It is used to get a

            // constant time of MAC computation and comparison on each record.

            if (box.isCBCMode()) {

                int remainingLen = calculateRemainingLen(

                                        signer, cipheredLength, contentLen);

                // NOTE: remainingLen may be bigger (less than 1 block of the

                // hash algorithm of the MAC) than the cipheredLength.

                //

                // Is it possible to use a static buffer, rather than allocate

                // it dynamically?

                remainingLen += signer.MAClen();

                ByteBuffer temporary = ByteBuffer.allocate(remainingLen);

                // Won't need to worry about the result on the remainder. And

                // then we won't need to worry about what's actual data to

                // check MAC tag on.  We start the check from the header of the

                // buffer so that we don't need to construct a new byte buffer.

                checkMacTags(contentType, temporary, signer, sequence, true);

            }

        }

        // Is it a failover?

        if (reservedBPE != null) {

            throw reservedBPE;

        }

        return bb.slice();

    }

    /*

     * Run MAC computation and comparison

     *

     */

    private static boolean checkMacTags(byte contentType, ByteBuffer bb,

            MAC signer, byte[] sequence, boolean isSimulated) {

        int tagLen = signer.MAClen();

        int position = bb.position();

        int lim = bb.limit();

        int macOffset = lim - tagLen;

        bb.limit(macOffset);

        byte[] hash = signer.compute(contentType, bb, sequence, isSimulated);

        if (hash == null || tagLen != hash.length) {

            // Something is wrong with MAC implementation.