With Python 3.4.0 you get an OSError if you try to extractall() the uploaded tar_which_is_cut.tar. That's nice.

Seems like only 2.7 seems to be buggy.

===> python3
Python 3.4.0 (default, Apr 11 2014, 13:05:11) 
[GCC 4.8.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tarfile
>>> tarfile.TarFile('tar_which_is_cut.tar').extractall()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.4/tarfile.py", line 1979, in extractall
    self.extract(tarinfo, path, set_attrs=not tarinfo.isdir())
  File "/usr/lib/python3.4/tarfile.py", line 2018, in extract
    set_attrs=set_attrs)
  File "/usr/lib/python3.4/tarfile.py", line 2087, in _extract_member
    self.makefile(tarinfo, targetpath)
  File "/usr/lib/python3.4/tarfile.py", line 2133, in makefile
    copyfileobj(source, target, tarinfo.size)
  File "/usr/lib/python3.4/tarfile.py", line 247, in copyfileobj
    raise OSError("end of file reached")
OSError: end of file reached