killing thread ?

[Peter Hansen]

Jp Calderone wrote:
> 
> On Fri, Jan 24, 2003 at 07:52:08AM -0800, Paul Rubin wrote:
> > Wha?  Python provides the rexec and bastion modules specifically to
> > have a way to run hostile code in a sandbox.  So what kind of advice
> > is "don't use Python"?  If sandboxed code can be prevented from
> > accessing sensitive data or doing i/o, but can't be prevented from
> > looping unkillably, that's a bug in Python.
> 
>   Yes, that's why Python provides them.  But this misconception (that they
> work) is also why it will soon -not- provide them :P  And neither RExec nor
> Bastion ever protected you against "while 1: pass" or "100L ** 100L ** 100L
> ** 100L ** 100L".  It is currently not possible to write a secure sandbox in
> Python.  I'm not sure if you can call that a bug; it's certainly
> unfortunate.

I always hate to describe something I know next to nothing about, but
I vaguely recall reading about something Zope does, I think, with munging
the generated *bytecode* to ensure that infinite loops and certain other
resource-stealing attacks (like range(1000000)) cannot work effectively.

That's not really using pure *Python*, although perhaps it can be effective
and maybe even reliable as a solution to this tricky problem.

-Peter