Is unpickling data a security risk?

[Andrew M. Kuchling]

"Fredrik Lundh" <effbot at telia.com> writes:
> you can plug this hole by using a custom unpickler, where the
> find_class method is overridden (see the pickle source code for
> details).  but there might be other holes in there...

Note that the Unpickler type in the cPickle (*not* pickle) module has
a .noload() method. From the docstring:

====
noload() -- not load a pickle, but go through most of the motions

This function can be used to read past a pickle without instantiating
any objects or importing any modules.  It can also be used to find all
persistent references without instantiating any objects or importing
any modules.
====

This feature should probably be back-ported to pickle.py

-- 
A.M. Kuchling			http://starship.python.net/crew/amk/
Constraints often boost creativity.
  -- Jim Hugunin, 11 Feb 1999