121 lines
4.1 KiB
Java
121 lines
4.1 KiB
Java
/*
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* Copyright (C) 2017 Schürmann & Breitmoser GbR
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
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import org.bouncycastle.util.Arrays;
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import org.bouncycastle.util.encoders.Hex;
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import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
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class Block {
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private static final int MAX_PAYLOAD_LEN = 254;
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private static final int OFFSET_NAD = 0;
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static final int OFFSET_PCB = 1;
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private static final int OFFSET_LEN = 2;
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private static final int OFFSET_DATA = 3;
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private final byte[] blockData;
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private final BlockChecksumAlgorithm checksumType;
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Block(BlockChecksumAlgorithm checksumType, byte[] data) throws UsbTransportException {
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this.checksumType = checksumType;
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this.blockData = data;
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int checksumOffset = blockData.length - checksumType.getLength();
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byte[] checksum = checksumType.computeChecksum(data, 0, checksumOffset);
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if (!Arrays.areEqual(checksum, getEdc())) {
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throw new UsbTransportException("TPDU CRC doesn't match");
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}
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}
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/*
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protected Block(BlockChecksumType checksumType, byte nad, byte pcb, byte[] apdu, int offset, int length)
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throws UsbTransportException {
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apdu = Arrays.copyOfRange(apdu, offset, offset + length);
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this.checksumType = checksumType;
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if (apdu.length > MAX_PAYLOAD_LEN) {
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throw new UsbTransportException("APDU is too long; should be split");
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}
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blockData = Arrays.concatenate(
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new byte[]{nad, pcb, (byte) apdu.length},
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apdu,
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new byte[checksumType.getLength()]);
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int checksumOffset = blockData.length - checksumType.getLength();
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byte[] checksum = checksumType.computeChecksum(blockData, 0, checksumOffset);
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System.arraycopy(checksum, 0, blockData, checksumOffset, checksumType.getLength());
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}
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*/
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// /*
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Block(BlockChecksumAlgorithm checksumType, byte nad, byte pcb, byte[] apdu, int offset, int length)
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throws UsbTransportException {
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this.checksumType = checksumType;
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if (length > MAX_PAYLOAD_LEN) {
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throw new IllegalArgumentException("Payload too long! " + length + " > " + MAX_PAYLOAD_LEN);
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}
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int lengthWithoutChecksum = length + 3;
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int checksumLength = this.checksumType.getLength();
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blockData = new byte[lengthWithoutChecksum + checksumLength];
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blockData[0] = nad;
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blockData[1] = pcb;
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blockData[2] = (byte) length;
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System.arraycopy(apdu, offset, blockData, 3, length);
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byte[] checksum = this.checksumType.computeChecksum(blockData, 0, lengthWithoutChecksum);
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System.arraycopy(checksum, 0, blockData, lengthWithoutChecksum, checksumLength);
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}
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public byte getNad() {
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return blockData[OFFSET_NAD];
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}
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public byte getPcb() {
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return blockData[OFFSET_PCB];
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}
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public byte getLen() {
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return blockData[OFFSET_LEN];
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}
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public byte[] getEdc() {
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return Arrays.copyOfRange(blockData, blockData.length - checksumType.getLength(), blockData.length);
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}
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public BlockChecksumAlgorithm getChecksumType() {
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return checksumType;
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}
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public byte[] getApdu() {
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return Arrays.copyOfRange(blockData, OFFSET_DATA, blockData.length - checksumType.getLength());
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}
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public byte[] getRawData() {
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return blockData;
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}
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@Override
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public String toString() {
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return Hex.toHexString(blockData);
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}
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}
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