[Python-Dev] Pickle alternative in stdlib (Was: On breaking modules into packages)

[Guido van Rossum]

On Thu, Nov 4, 2010 at 9:15 AM, anatoly techtonik <techtonik at gmail.com> wrote:
> pickle is insecure, marshal too.

What's the attack you're thinking of on marshal? It never executes any
code while unmarshalling (although it can unmarshal code objects --
but the receiving program has to do something additionally to execute
those).

> What about JSON? IIUC you need a
> definition of a class to be able to unserialize it in all cases. I
> wonder how is this definition validated, i.e. what to watch for when
> modifying classes that can be serialized.

Security is all in the code used to deserialize. I haven't analyzed
the json library that comes in the stdlib these days, but couldn't it
in theory be as safe as XML? (Not that there haven't been any attacks
on XML -- but they depended on bugs in the unmarshalling code, the
format itself is not insecure.)

-- 
--Guido van Rossum (python.org/~guido)