Sandboxes

[42]

Hi,

I'm extremely new to python, and am looking at using it as an embedded 
script engine in a dotnet project I'm working on. I'm currently playing 
with the "Python for Net" (http://www.zope.org/Members/Brian/PythonNet) 
stuff, and it seems to work well.

Googling for information on securing Python in a "sandbox" seems 
indicate that there are some built in features, but they aren't really 
trustworthy. Is that correct?

For my purposes, I really just want to let users run in a sandbox, with 
access to only the language, manipuate a few published objects in the 
application (and perhaps give them some string and math libraries if 
applicable).

I was wondering if it would be effective to pre-parse incoming scripts 
and reject those containing "import"? I'd also have the application 
inject the (short) list of trusted imports to the script before passing 
it to the interpreter.

In theory I'm hoping this would mean script writers would have access to 
the stuff they need and no way to add in anything else.

Would this sufficient? Are there any drawbacks or giant gaping holes? 
I'm anticipating that I'd also need to block 'exec' and 'eval' to 
prevent an import from being obfuscated past the pre-parse.

Or is this a hopeless cause? 

Finally, either way, would anyone recommend a different script engine 
that might be more suitable for what I'm trying to accomplish that I 
might not have looked at. I don't need much; it needs to work with C#, 
and be able to easily interact with 'published' interface. I'd also like 
to leverage a "popular" language instead of something obscure.

I also looked at Javascript, but couldn't find a way to embed an 
interpreter into a C# app. There's some CodeDom stuff with JScript, but 
that seemed backwards...overkill; I don't really want to compile 
temporary assemblies for hundreds of 2 and 3 line scripts... and the VSA 
stuff has been marked deprecated with no apparent successor... seems 
like I jumped into this at precisely the wrong time. :)

Any thoughts, insights, or comments welcome. Forgive my lack of Python 
savvy... I've only been playing with it for a few hours now; after 
bumping into the "python for net" link.

-regards,
Dave