is there a safe marshaler?

[Irmen de Jong]

Fredrik Lundh wrote:

> the problem is that the following may or may not reach the "done!" statement,
> somewhat depending on python version, memory allocator, and what data you
> pass to dumps.
> 
> import marshal
> 
> data = marshal.dumps((1, 2, 3, "hello", 4, 5, 6))
> 
> for i in range(len(data), -1, -1):
>     try:
>         print marshal.loads(data[:i])
>     except EOFError:
>         print "EOFError"
>     except ValueError:
>         print "ValueError"
> 
> print "done!"
> 
> (try different data combinations, to see how far you get on your platform...)

Python 2.4 on my windows box crashes with
Fatal Python error: PyString_InternInPlace: strings only please!

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
c:\> _


So indeed it seems that marshal is not safe yet :-|


> fixing this should be relatively easy, and should result in a safe unmarshaller (your
> application will still have to limit the amount of data fed into load/loads, of course).

Okay.

--Irmen