[Python-Dev] Reviving restricted mode? (original) (raw)

Guido van Rossum guido at python.org
Mon Feb 23 04:56:20 CET 2009

On Sun, Feb 22, 2009 at 7:39 PM, P.J. Eby <pje at telecommunity.com> wrote:

At 08:45 AM 2/22/2009 -0800, Guido van Rossum wrote:

I've received some enthusiastic emails from someone who wants to revive restricted mode. He started out with a bunch of patches to the CPython runtime using ctypes, which he attached to an App Engine bug: http://code.google.com/p/googleappengine/issues/detail?id=671 Based on his code (the file secure.py is all you need, included in secure.tar.gz) it seems he believes the only security leaks are subclasses, giframe and gicode. (I have since convinced him that if we add "restricted" guards to these attributes, he doesn't need the functions added to sys.) I don't recall the exploits that Samuele once posted that caused the death of rexec.py -- does anyone recall, or have a pointer to the threads? Just a question, but, if you just need a pure-python restricted environment for App Engine, why not just use the RestrictedPython package (i.e., http://pypi.python.org/pypi/RestrictedPython )?

How does that work? Remember, app engine doesn't support certain things, and bytecode manipulations (if that's what RestrictedPython does) are one of the unsupported things.

The other reason I can think of is that Tav is a capabilities purist. :-)

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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