Beispiel #1
0
  private void validate() throws IOException {
    long compressedSize = inCounted.getSize();

    // Validate Compressed Size and Uncompressed Size if they were
    // present in Block Header.
    if ((compressedSizeInHeader != -1 && compressedSizeInHeader != compressedSize)
        || (uncompressedSizeInHeader != -1 && uncompressedSizeInHeader != uncompressedSize))
      throw new CorruptedInputException();

    // Block Padding bytes must be zeros.
    while ((compressedSize++ & 3) != 0)
      if (inData.readUnsignedByte() != 0x00) throw new CorruptedInputException();

    // Validate the integrity check.
    byte[] storedCheck = new byte[check.getSize()];
    inData.readFully(storedCheck);
    if (!Arrays.equals(check.finish(), storedCheck))
      throw new CorruptedInputException("Integrity check (" + check.getName() + ") does not match");
  }
Beispiel #2
0
  public BlockInputStream(
      InputStream in,
      Check check,
      int memoryLimit,
      long unpaddedSizeInIndex,
      long uncompressedSizeInIndex)
      throws IOException, IndexIndicatorException {
    this.check = check;
    inData = new DataInputStream(in);

    byte[] buf = new byte[DecoderUtil.BLOCK_HEADER_SIZE_MAX];

    // Block Header Size or Index Indicator
    inData.readFully(buf, 0, 1);

    // See if this begins the Index field.
    if (buf[0] == 0x00) throw new IndexIndicatorException();

    // Read the rest of the Block Header.
    headerSize = 4 * ((buf[0] & 0xFF) + 1);
    inData.readFully(buf, 1, headerSize - 1);

    // Validate the CRC32.
    if (!DecoderUtil.isCRC32Valid(buf, 0, headerSize - 4, headerSize - 4))
      throw new CorruptedInputException("XZ Block Header is corrupt");

    // Check for reserved bits in Block Flags.
    if ((buf[1] & 0x3C) != 0)
      throw new UnsupportedOptionsException("Unsupported options in XZ Block Header");

    // Memory for the Filter Flags field
    int filterCount = (buf[1] & 0x03) + 1;
    long[] filterIDs = new long[filterCount];
    byte[][] filterProps = new byte[filterCount][];

    // Use a stream to parse the fields after the Block Flags field.
    // Exclude the CRC32 field at the end.
    ByteArrayInputStream bufStream = new ByteArrayInputStream(buf, 2, headerSize - 6);

    try {
      // Set the maximum valid compressed size. This is overriden
      // by the value from the Compressed Size field if it is present.
      compressedSizeLimit = (DecoderUtil.VLI_MAX & ~3) - headerSize - check.getSize();

      // Decode and validate Compressed Size if the relevant flag
      // is set in Block Flags.
      if ((buf[1] & 0x40) != 0x00) {
        compressedSizeInHeader = DecoderUtil.decodeVLI(bufStream);

        if (compressedSizeInHeader == 0 || compressedSizeInHeader > compressedSizeLimit)
          throw new CorruptedInputException();

        compressedSizeLimit = compressedSizeInHeader;
      }

      // Decode Uncompressed Size if the relevant flag is set
      // in Block Flags.
      if ((buf[1] & 0x80) != 0x00) uncompressedSizeInHeader = DecoderUtil.decodeVLI(bufStream);

      // Decode Filter Flags.
      for (int i = 0; i < filterCount; ++i) {
        filterIDs[i] = DecoderUtil.decodeVLI(bufStream);

        long filterPropsSize = DecoderUtil.decodeVLI(bufStream);
        if (filterPropsSize > bufStream.available()) throw new CorruptedInputException();

        filterProps[i] = new byte[(int) filterPropsSize];
        bufStream.read(filterProps[i]);
      }

    } catch (IOException e) {
      throw new CorruptedInputException("XZ Block Header is corrupt");
    }

    // Check that the remaining bytes are zero.
    for (int i = bufStream.available(); i > 0; --i)
      if (bufStream.read() != 0x00)
        throw new UnsupportedOptionsException("Unsupported options in XZ Block Header");

    // Validate the Blcok Header against the Index when doing
    // random access reading.
    if (unpaddedSizeInIndex != -1) {
      // Compressed Data must be at least one byte, so if Block Header
      // and Check alone take as much or more space than the size
      // stored in the Index, the file is corrupt.
      int headerAndCheckSize = headerSize + check.getSize();
      if (headerAndCheckSize >= unpaddedSizeInIndex)
        throw new CorruptedInputException("XZ Index does not match a Block Header");

      // The compressed size calculated from Unpadded Size must
      // match the value stored in the Compressed Size field in
      // the Block Header.
      long compressedSizeFromIndex = unpaddedSizeInIndex - headerAndCheckSize;
      if (compressedSizeFromIndex > compressedSizeLimit
          || (compressedSizeInHeader != -1 && compressedSizeInHeader != compressedSizeFromIndex))
        throw new CorruptedInputException("XZ Index does not match a Block Header");

      // The uncompressed size stored in the Index must match
      // the value stored in the Uncompressed Size field in
      // the Block Header.
      if (uncompressedSizeInHeader != -1 && uncompressedSizeInHeader != uncompressedSizeInIndex)
        throw new CorruptedInputException("XZ Index does not match a Block Header");

      // For further validation, pretend that the values from the Index
      // were stored in the Block Header.
      compressedSizeLimit = compressedSizeFromIndex;
      compressedSizeInHeader = compressedSizeFromIndex;
      uncompressedSizeInHeader = uncompressedSizeInIndex;
    }

    // Check if the Filter IDs are supported, decode
    // the Filter Properties, and check that they are
    // supported by this decoder implementation.
    FilterDecoder[] filters = new FilterDecoder[filterIDs.length];

    for (int i = 0; i < filters.length; ++i) {
      if (filterIDs[i] == LZMA2Coder.FILTER_ID) filters[i] = new LZMA2Decoder(filterProps[i]);
      else if (filterIDs[i] == DeltaCoder.FILTER_ID) filters[i] = new DeltaDecoder(filterProps[i]);
      else if (BCJDecoder.isBCJFilterID(filterIDs[i]))
        filters[i] = new BCJDecoder(filterIDs[i], filterProps[i]);
      else throw new UnsupportedOptionsException("Unknown Filter ID " + filterIDs[i]);
    }

    RawCoder.validate(filters);

    // Check the memory usage limit.
    if (memoryLimit >= 0) {
      int memoryNeeded = 0;
      for (int i = 0; i < filters.length; ++i) memoryNeeded += filters[i].getMemoryUsage();

      if (memoryNeeded > memoryLimit) throw new MemoryLimitException(memoryNeeded, memoryLimit);
    }

    // Use an input size counter to calculate
    // the size of the Compressed Data field.
    inCounted = new CountingInputStream(in);

    // Initialize the filter chain.
    filterChain = inCounted;
    for (int i = filters.length - 1; i >= 0; --i)
      filterChain = filters[i].getInputStream(filterChain);
  }
Beispiel #3
0
 public long getUnpaddedSize() {
   return headerSize + inCounted.getSize() + check.getSize();
 }