[Python-Dev] For sandboxing: alternative to crippling file()

[Greg Ewing]

Brett Cannon wrote:

> 1) Is removing 'file' from the builtins dict in PyInterpreterState (and 
> maybe some other things) going to be safe enough to sufficiently hide 
> 'file' confidently (short of someone being stupid in their C extension 
> module and exposing 'file' directly)?
> 
> 2) Changing open() to return C-implemented delegate objects for files 
> (and thus won't type check, but this is Python so I am not worried about 
> that too much) and delegate socket objects for IP and URL addresses.

My suggestion is to change things so that the constructor
of the file type doesn't open files (at least in restricted
mode). Then it wouldn't matter if untrusted code had real
file objects, as they couldn't use them to get access to
any other files.

--
Greg