[Python-ideas] Adding a safe alternative to pickle in the standard library

[Eric V. Smith]

On 2/21/2013 6:11 AM, Antoine Pitrou wrote:
> Le Thu, 21 Feb 2013 06:01:19 -0500,
> Devin Jeanpierre <jeanpierreda at gmail.com>
> a écrit :
>> I've been noticing a lot of security-related issues being discussed in
>> the Python world since the Ruby YAML problemcame out. Is it time to
>> consider adding an alternative to pickle that is safe(r) by default?
> 
> There's already json. Is something else needed?

As stated elsewhere, it's cycles and especially arbitrary python objects
that are the big draw for pickle.

I've always wanted a version of pickle.loads() that takes a list of
classes that are allowed to be instantiated. Often, when using pickle to
serialize over say AMQP or some other transport, I know what classes I
want to allow. Anything else is either a (not infrequent) logic error or
an attack of some sort.

I realize this isn't perfect, but it would certainly reduce the attack
surface for many of my use cases. I'm already authenticating the sender,
and when I'm really paranoid I also sign the pickles.

Just a thought.

-- 
Eric.