gzip file with trailing 0-byte values raises dfvfs.lib.errors.FileFormatError: Unsupported signature: 0x0000

[joachimmetz]

Traceback (most recent call last):
  File "tools/log2timeline.py", line 94, in <module>
    if not Main():
  File "tools/log2timeline.py", line 69, in Main
    tool.ExtractEventsFromSources()
  File "plaso/cli/log2timeline_tool.py", line 404, in ExtractEventsFromSources
    is_archive = self._IsArchiveFile(self._source_path_specs[0])
  File "plaso/cli/extraction_tool.py", line 249, in _IsArchiveFile
    type_indicators = dfvfs_analyzer.Analyzer.GetArchiveTypeIndicators(
  File "/usr/lib/python3.9/site-packages/dfvfs/analyzer/analyzer.py", line 245, in GetArchiveTypeIndicators
    return cls._GetTypeIndicators(
  File "/usr/lib/python3.9/site-packages/dfvfs/analyzer/analyzer.py", line 180, in _GetTypeIndicators
    file_object = resolver.Resolver.OpenFileObject(
  File "/usr/lib/python3.9/site-packages/dfvfs/resolver/resolver.py", line 109, in OpenFileObject
    file_object.Open()
  File "/usr/lib/python3.9/site-packages/dfvfs/file_io/file_io.py", line 89, in Open
    self._Open(mode=mode)
  File "/usr/lib/python3.9/site-packages/dfvfs/file_io/file_object_io.py", line 43, in _Open
    self._file_object = self._OpenFileObject(self._path_spec)
  File "/usr/lib/python3.9/site-packages/dfvfs/file_io/gzip_file_io.py", line 58, in _OpenFileObject
    gzip_compressed_stream.Open(file_object)
  File "/usr/lib/python3.9/site-packages/dfvfs/lib/gzipfile.py", line 485, in Open
    member = GzipMember(
  File "/usr/lib/python3.9/site-packages/dfvfs/lib/gzipfile.py", line 164, in __init__
    self._ReadMemberHeader(file_object)
  File "/usr/lib/python3.9/site-packages/dfvfs/lib/gzipfile.py", line 243, in _ReadMemberHeader
    raise errors.FileFormatError(
dfvfs.lib.errors.FileFormatError: Unsupported signature: 0x0000.

00000000  1f 8b 08 00 9d d5 7f 5d  00 03 ed 7d 79 40 14 47  |.......]...}[email protected]|
...
00003250  ff 01 5f 8b 14 7a 00 f0  00 00 00 00 00 00 00 00  |.._..z..........|
00003260  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00005000

[joachimmetz]

Both gunzip and Python gzip module seems to ignore the 0-byte values

import gzip
f = gzip.GzipFile('files/851412.anon_system_stats', 'r')
b = f.read()
len(b) => 61440

[joachimmetz]

gunzip seems to check for anything other than 0-byte values:

gzip: /tmp/851412.anon_system_stats.gz: decompression OK, trailing garbage ignored

Python gzip module seems to not check for anything other than 0-byte values