[Python-Dev] Sandboxing Python

[Victor Stinner]

> I challenge anymore to break pysandbox! I would be happy if anyone
> breaks it because it would make it more stronger.

Hum, I should give some rules for such contest:

- the C module (_sandbox) must be used
- you have to get access to a object outside the sandbox, like a real
module, or get access to a blocked resource (like the filesystem)
- the best is to be able to write into the filesystem
- you can use the interpreter ("python interpreter.py") to play with
the sandbox, but you have to be able to reproduce with a simple script
(e.g. using "python execfile.py script.py")

pysandbox works on Python 2.5, 2.6 and 2.7. It does not officially
support Python 3 yet.

Example.
---
$ python setup.py build
$ PYTHONPATH=build/lib.*/ python interpreter.py  --allow-path=/etc/issue
pysandbox 1.1
Enabled features: codecs, encodings, exit, interpreter, site, stderr,
stdin, stdout, traceback
(use --features=help to enable the help function)

Try to break the sandbox!

sandbox>>> open('/etc/issue').read()
'Ubuntu 11.10 \\n \\l\n\n'

sandbox>>> type(open('/etc/issue'))('test', 'w')
Traceback (most recent call last):
  File "<console>", line 1, in <module>
TypeError: object.__new__() takes no parameters
---
You fail!

I'm interested by vulnerabilities in pysandbox using the Python
restricted module (used when _sandbox is missing), but it is not the
official mode :-) And it is more limited: you cannot read files for
example.

See also sandbox tests to get some ideas ;-)

Victor