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https://github.com/oxen-io/session-android.git
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Refactor relationship between SessionCipher and Message.
This commit is contained in:
Moxie Marlinspike
@@ -1,207 +0,0 @@
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/**
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* Copyright (C) 2011 Whisper Systems
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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.thoughtcrime.securesms.mms;
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import java.io.ByteArrayInputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.zip.CRC32;
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import java.util.zip.DeflaterOutputStream;
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import java.util.zip.InflaterInputStream;
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import org.whispersystems.textsecure.crypto.SessionCipher;
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import org.whispersystems.textsecure.crypto.TransportDetails;
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import org.whispersystems.textsecure.util.Conversions;
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import android.util.Log;
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public class PngTransport implements TransportDetails {
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private static final int CRC_LENGTH = 4;
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private static final int IHDR_WIDTH_OFFSET = 8;
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private static final int IHDR_HEIGHT_OFFSET = 12;
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private static final int IDAT_HEADER_LENGTH = 8;
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private static final byte[] PNG_HEADER = {(byte)0x89, (byte)0x50, (byte)0x4E, (byte)0x47, (byte)0x0D, (byte)0x0A, (byte)0x1A, (byte)0x0A};
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private static final byte[] IHDR_CHUNK = {(byte)0x00, (byte)0x00, (byte)0x00, (byte)0x0D, (byte)0x49, (byte)0x48, (byte)0x44, (byte)0x52,
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(byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00,
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(byte)0x10, (byte)0x06, (byte)0x00, (byte)0x00, (byte)0x00};
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private static final byte[] IEND_CHUNK = {(byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x49, (byte)0x45, (byte)0x4E, (byte)0x44};
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private static final byte[] IDAT_TAG = {(byte)0x49, (byte)0x44, (byte)0x41, (byte)0x54};
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private static final int BYTES_PER_ROW = 640 * 8;
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private static final int IDAT_LENGTH_OFFSET = 33;
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private void readFully(InputStream in, byte[] buffer) throws IOException {
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int totalRead = 0;
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int read = 0;
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while (totalRead < buffer.length) {
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read = in.read(buffer, totalRead, buffer.length-totalRead);
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Log.w("PngTransport", "Read: " + read);
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if (read == -1)
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throw new IOException("Could not fill buffer!");
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totalRead+=read;
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}
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}
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private int getImageHeight(byte[] data) {
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int rows = (data.length / BYTES_PER_ROW);
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assert(data.length % BYTES_PER_ROW == 0);
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return rows;
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}
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private byte[] getIhdr(int width, int height) {
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byte[] ihdr = new byte[IHDR_CHUNK.length];
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System.arraycopy(IHDR_CHUNK, 0, ihdr, 0, ihdr.length);
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Conversions.intToByteArray(ihdr, IHDR_WIDTH_OFFSET, width);
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Conversions.intToByteArray(ihdr, IHDR_HEIGHT_OFFSET, height);
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return ihdr;
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}
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private byte[] calculateChunkCrc(byte[] header, byte[] chunk) {
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byte[] crcBytes = new byte[4];
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CRC32 crc = new CRC32();
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crc.update(header, 4, header.length - 4);
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if (chunk != null)
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crc.update(chunk, 0, chunk.length);
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long crcValue = crc.getValue();
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Conversions.longTo4ByteArray(crcBytes, 0, crcValue);
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return crcBytes;
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}
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private int readIhdr(ByteArrayInputStream bais) throws IOException {
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byte[] ihdr = new byte[IHDR_CHUNK.length];
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bais.read(ihdr);
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return Conversions.byteArrayToInt(ihdr, IHDR_HEIGHT_OFFSET);
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}
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private byte[] readIdatChunk(ByteArrayInputStream bais, int rows) throws IOException {
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InflaterInputStream iis = new InflaterInputStream(bais);
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ByteArrayOutputStream baos = new ByteArrayOutputStream();
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byte[] buffer = new byte[BYTES_PER_ROW + 1];
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Log.w("PngTransport", "Total image height: " + rows);
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for (int i=0;i<rows;i++) {
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readFully(iis, buffer);
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Log.w("PngTransport", "Read row: " + i);
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baos.write(buffer, 1, buffer.length-1);
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}
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return baos.toByteArray();
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}
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private byte[] getIdatChunkHeader(byte[] chunk) {
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byte[] headerBytes = new byte[8];
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Conversions.intToByteArray(headerBytes, 0, chunk.length);
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System.arraycopy(IDAT_TAG, 0, headerBytes, 4, IDAT_TAG.length);
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return headerBytes;
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}
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private byte[] getIdatChunk(byte[] data) {
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try {
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int rows = (data.length / BYTES_PER_ROW);
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assert(data.length % BYTES_PER_ROW == 0);
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Log.w("PngTransport", "data % bytes_per_row: " + (data.length % BYTES_PER_ROW));
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ByteArrayOutputStream baos = new ByteArrayOutputStream((rows * BYTES_PER_ROW) + rows);
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DeflaterOutputStream dos = new DeflaterOutputStream(baos);
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for (int i=0;i<rows;i++) {
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dos.write((byte)0x00);
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dos.write(data, (i*BYTES_PER_ROW), BYTES_PER_ROW);
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}
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dos.close();
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return baos.toByteArray();
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} catch (IOException ioe) {
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throw new AssertionError(ioe);
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}
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}
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public byte[] encodeMessage(byte[] data) {
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try {
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int height = getImageHeight(data);
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byte[] idatChunk = getIdatChunk(data);
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byte[] idatChunkHeader = getIdatChunkHeader(idatChunk);
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byte[] ihdrChunk = getIhdr(640, height);
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ByteArrayOutputStream baos = new ByteArrayOutputStream(PNG_HEADER.length + IHDR_CHUNK.length + CRC_LENGTH +
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idatChunkHeader.length + idatChunk.length + CRC_LENGTH +
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IEND_CHUNK.length + CRC_LENGTH);
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baos.write(PNG_HEADER);
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baos.write(ihdrChunk);
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baos.write(calculateChunkCrc(ihdrChunk, null));
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baos.write(idatChunkHeader);
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baos.write(idatChunk);
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baos.write(calculateChunkCrc(idatChunkHeader, idatChunk));
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baos.write(IEND_CHUNK);
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baos.write(calculateChunkCrc(IEND_CHUNK, null));
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return baos.toByteArray();
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} catch (IOException ioe) {
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throw new AssertionError(ioe);
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}
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}
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public byte[] decodeMessage(byte[] encodedMessageBytes) throws IOException {
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if (encodedMessageBytes.length < IDAT_LENGTH_OFFSET + 5)
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throw new IOException("Encoded bytes too short!");
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ByteArrayInputStream bais = new ByteArrayInputStream(encodedMessageBytes);
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bais.skip(PNG_HEADER.length);
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int rows = readIhdr(bais);
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bais.skip(CRC_LENGTH);
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bais.skip(IDAT_HEADER_LENGTH);
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return readIdatChunk(bais, rows);
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}
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public byte[] getPaddedMessageBody(byte[] messageBody) {
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int rows = ((SessionCipher.ENCRYPTED_MESSAGE_OVERHEAD + messageBody.length) / BYTES_PER_ROW) + 1;
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byte[] paddedMessage = new byte[(rows * BYTES_PER_ROW) - SessionCipher.ENCRYPTED_MESSAGE_OVERHEAD];
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System.arraycopy(messageBody, 0, paddedMessage, 0, messageBody.length);
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paddedMessage[messageBody.length] = (byte)0x01;
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return paddedMessage;
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}
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public byte[] stripPaddedMessage(byte[] messageWithPadding) {
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int i;
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for (i=messageWithPadding.length-1;i>=0;i--) {
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if (messageWithPadding[i] == (byte)0x01)
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break;
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else if (i == 0)
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throw new AssertionError("No padding!");
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}
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int paddingLength = messageWithPadding.length - i;
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byte[] message = new byte[messageWithPadding.length - paddingLength];
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System.arraycopy(messageWithPadding, 0, message, 0, message.length);
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return message;
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}
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}
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@@ -23,19 +23,23 @@ import org.whispersystems.textsecure.util.Base64;
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public class TextTransport implements TransportDetails {
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public byte[] decodeMessage(byte[] encodedMessageBytes) throws IOException {
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@Override
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public byte[] getDecodedMessage(byte[] encodedMessageBytes) throws IOException {
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return Base64.decode(encodedMessageBytes);
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}
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public byte[] encodeMessage(byte[] messageWithMac) {
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@Override
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public byte[] getEncodedMessage(byte[] messageWithMac) {
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return Base64.encodeBytes(messageWithMac).getBytes();
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}
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@Override
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public byte[] getPaddedMessageBody(byte[] messageBody) {
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return messageBody;
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}
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public byte[] stripPaddedMessage(byte[] messageWithPadding) {
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@Override
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public byte[] getStrippedPaddingMessageBody(byte[] messageWithPadding) {
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return messageWithPadding;
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}
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