[Zope-dev] RestrictedPython

[Chris Withers]

Martijn Faassen wrote:
> It's good to know we have some eyes on this particular topic. Thanks
> Stephan! I talked to Chris about this at the EuroPython conference
> after Chris started offering free beer and even bottles of champagne
> for people who could point out flaws (beer) and submit fixes with
> tests (champagne). Unfortunately for everybody now suddenly hopeful
> this offer has since expired (nobody took him up on it during
> EuroPython :).


...and unfortunately, from chatting with some of the PyPy guys, I set an 
unfair challenge too: you couldn't even iterate over [1,2,3] in the 
environment I set in the challenge.

The problem is that the module is poorly documented and tested. The docs 
on PyPI cover one specific use path and that's not even the one used by 
Zope 2's PythonScripts.

The PyPy guys are also of the opinion that the AST hacking is completely 
the wrong way to go about creating a restricted python environment.
They gave an interesting lightning talk where they showed a truly 
restricted environment where you could still do all the "normal" python 
things except the provider of the restricted environment had to actively 
implement hooks for any c-level stuff to be do-able. They could also 
control the maximum amount of memory the restricted environment could 
consume, which is something we sorely miss in RestrictedPython.
(the code they were using is up here:
  http://codespeak.net/pypy/dist/pypy/doc/sandbox.html
  ...and in particular:
  http://codespeak.net/svn/pypy/dist/pypy/translator/sandbox/sandlib.py)

I think the "right" thing to do here is engage with the PyPy guys on 
their mailing list:

http://codespeak.net/mailman/listinfo/pypy-dev

...and work with their guidance to re-implement RestrictedPython in a 
way that doesn't use AST hacks. I suspect we'll likely end up with a 
much faster and more robust environment.

It would be great if, on the way, RestrictedPython was fully documented 
and tested...

cheers,

Chris

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