Endless loop in constructor with empty ByteArrayInputStream

[mikrovvelle]

The following code, using the SasFileReaderImpl class, will lead to an endless loop:

  byte[] emptyArray = new byte[0];
  ByteArrayInputStream emptyStream = new ByteArrayInputStream(emptyArray);
  SasFileReaderImpl emptyByteArrayStreamReader = new SasFileReaderImpl(emptyStream);

Probably no one should be passing in empty ByteArrayInputStreams to the constructor, but instead of getting caught in an endless loop, it would be helpful to throw an exception instead. This would allow classes extending SasFileReaderImpl to easily catch this kind of bad input.

---

The loop takes place in getBytesFromFile in SasFileParser, line 750:

  while (actuallySkipped < offset[i] - currentFilePosition) {
    try {
      actuallySkipped += sasFileStream.skip(offset[i] - currentFilePosition - actuallySkipped);
    } catch (IOException e) {
      // never reach this far

actuallySkipped and currentFilePosition are stuck at 0, while offset[0] is 32, so the while statement never exits.

[syjer]

Hi, I was kinda reluctant to open the issue here, as it has an impact on the Apache Tika project and I was trying to figure out who to contact and how.

You can do a Denial of Service with a correctly crafted input, so this issue is quite important.

See the gists: https://gist.github.com/syjer/9ffebab4538fbc4242d10e50fa5a4454

[printsev]

closed thanks to xantorohara