Hacker News Reader

Comment by tptacek | Hacker News Reader

It sure sounds like you said "No, <stuff> <stuff> <stuff>, but yes."

I guess it was, "no, it shouldn't be, except that the pickle module is broken by design."

I.e., data structure parsing should not require a Turing-complete language. If it does, your serialization format is broken.

But yeah, I can see the issue with my original comment.

Pickle isn't a data structure parsing system, though. It's a system for dumping out and restoring (parts of) the state of the Python interpreter. If pyasn1 allowed code execution or method invocation, you could say it was broken by design. You can't say that about Pickle.

Since the pickle module doesn't marshal many types of stateful objects (filehandles, functions, etc.), I'm not sure it's fair to describe it as a means of saving the "state of the Python interpreter". It really just serves to save a compact representation of data on disk, without explicitly managing packing an unpacking from the binary serialization.

In that respect, it intuitively seems like it should behave more like the ASN1 or YAML formats w.r.t. the safety of data loaded from it. I may understand the risks, and you may understand the risks, but I think that a new Python programmer could be forgiven for simply scanning the standard library documentation and thinking that the pickle format would be safe for transport across untrusted channels.

Just add crypthographic authentication (and hashes) and some problems go away.

No, they are saying that Pickle as it is currently designed is too powerful. Depending on the goals of Pickle, it may be possible to reduce its power by redesigning it to do no more than its goals.

And I'm saying "pickle isn't really designed to solve the problem they're saying it's bad at solving".

So If we reduce the scope of Pickle's goals then the current Pickle that meets its current goals is to strong, and could be reduced.

Reply on news.ycombinator.com