com.hierynomus.mssmb2.SMB2TransformHeader Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of smbj Show documentation
SMB2 protocol library for communication with Windows servers
There is a newer version: 0.13.0
/*
 * Copyright (C)2016 - SMBJ Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.hierynomus.mssmb2;

import com.hierynomus.protocol.commons.buffer.Buffer;
import com.hierynomus.smb.SMBBuffer;
import com.hierynomus.smb.SMBHeader;
import com.hierynomus.smbj.common.Check;

/**
 * [MS-SMB2] 2.2.41 SMB2 TRANSFORM_HEADER
 * 
 * The SMB2 TRANSFORM_HEADER is used by the client or server when sending encrypted messages.
 * The SMB2 TRANSFORM_HEADER is only valid for the SMB 3.x dialect family.
 */
public class SMB2TransformHeader implements SMBHeader {
    public static final byte[] ENCRYPTED_PROTOCOL_ID = {(byte) 0xFD, 'S', 'M', 'B'};
    private int headerStartPosition;
    private byte[] signature;
    private byte[] nonce;
    private int originalMessageSize;
    private int flagsEncryptionAlgorithm;
    private long sessionId;
    private int messageEndPosition;

    public SMB2TransformHeader(byte[] nonce, int originalMessageSize, long sessionId) {
        this.signature = new byte[16]; // Assign empty signature so that creating the AAD is successful
        this.nonce = nonce;
        this.originalMessageSize = originalMessageSize;
        this.sessionId = sessionId;
    }

    public SMB2TransformHeader() {
    }

    @Override
    public void writeTo(SMBBuffer buffer) {
        this.headerStartPosition = buffer.rpos(); // Keep track of the header start position.
        buffer.putRawBytes(ENCRYPTED_PROTOCOL_ID); // ProtocolId (4 bytes)
        buffer.putRawBytes(signature); // Signature (16 bytes)
        buffer.putRawBytes(nonce); // Nonce (11/12 bytes) (depending on algorithm)
        buffer.putReserved(16 - nonce.length); // Reserved (4/5 bytes)
        buffer.putUInt32(originalMessageSize); // OriginalMessageSize (4 bytes)
        buffer.putReserved2(); // Reserved (2 bytes)
        buffer.putUInt16(0x01); // Flags/EncryptionAlgorithm (2 bytes)
        buffer.putLong(sessionId); // SessionId (8 bytes)
    }

    @Override
    public void readFrom(Buffer buffer) throws Buffer.BufferException {
        this.headerStartPosition = buffer.rpos(); // Keep track of the header start position.
        byte[] protocolId = buffer.readRawBytes(4); // ProtocolId (4 bytes) (already verified)
        Check.ensureEquals(protocolId, ENCRYPTED_PROTOCOL_ID, "Could not find SMB2 Packet header");
        this.signature = buffer.readRawBytes(16); // Signature (16 bytes)
        this.nonce = buffer.readRawBytes(16); // Nonce (16 bytes)
        this.originalMessageSize = buffer.readUInt32AsInt(); // OriginalMessageSize (4 bytes)
        buffer.skip(2); // Reserved (2 bytes)
        this.flagsEncryptionAlgorithm = buffer.readUInt16(); // Flags/EncryptionAlgorithm (2 bytes)
        this.sessionId = buffer.readLong(); // SessionId (8 bytes)
        this.messageEndPosition = buffer.wpos();
    }

    @Override
    public int getHeaderStartPosition() {
        return headerStartPosition;
    }

    @Override
    public int getMessageEndPosition() {
        return messageEndPosition;
    }

    public void setMessageEndPosition(int messageEndPosition) {
        this.messageEndPosition = messageEndPosition;
    }

    public byte[] getSignature() {
        return signature;
    }

    public void setSignature(byte[] signature) {
        this.signature = signature;
    }

    public byte[] getNonce() {
        return nonce;
    }

    public int getOriginalMessageSize() {
        return originalMessageSize;
    }

    public int getFlagsEncryptionAlgorithm() {
        return flagsEncryptionAlgorithm;
    }

    public long getSessionId() {
        return sessionId;
    }
}