Opening corrupt Aperio SVS file causes Out-of-Memory error

Hi @cgohlke

I encountered a corrupted AperioSVS file that causes a machine with 64GB of ram to run out-of-memory when trying to instantiate the TiffFile instance. Creating the instance causes a dramatic increase in process memory usage in the TiffTag loading part of tifffile, which just causes the server to kill the python process. Ideally I would expect the code to just crash early, so that cleanup can happen in python.

Sadly I can’t share the file, so here’s some additional information:

The filesize is 5958078846 bytes and it’s recognized as TIFF.CLASSIC_LE tifffile detects tagno=3126 tags, of which almost all raise an unknown tag data type error. Then for tag tagno=2327 it calls TiffTag.from_file with offset=3256275384 and header=b'\x01\x00\x02\x00\x00?\x00\xeb5\x05\x92\x1b'

Which due to the large count causes a ~4.000.000 character string to be unpacked later in this code path and due to some string ops causes a massive increase in Memory consumption.

I was wondering if there are upper bounds on the amount of data a TiffTag can contain, and this codepath could error early.

Cheers, Andreas 😃

[cgohlke]

Should be mitigated by v2021.11.2, which delay-loads non-essential TIFF tag values.

[ap--]

Tested with all corrupted files that were problematic and it works perfectly now. Thank you so much!