[Python-Dev] Is core dump always a bug? Advice requested (original) (raw)

Phillip J. Eby pje at telecommunity.com
Tue May 11 23:33:53 EDT 2004

At 10:14 PM 5/11/04 -0400, Fred L. Drake, Jr. wrote:

On Tuesday 11 May 2004 10:06 pm, Greg Ewing wrote: > Just a thought, but is statically verifying the bytecode even > possible in principle? Seems to me it could be equivalent to > the halting problem.

I don't see any reason to think them equivalent; we don't need to determine that the code will execute to completion, only that the bytecodes can be decoded without error. Not trivial by any means, but I think it's a more constrained problem.

Right; it should be possible, for example, to verify stack depth used, that stack growth isn't unlimited, that there is a return at the end, no invalid references to locals or co_names, and so on. Basic "sanity" stuff, not in-depth analysis.

But it isn't clear to me that this is really necessary for new.code(), let alone .pyc/.pyo files. And anybody that's crazy enough to send bytecode "over the wire" as part of an agent system or whatever darn well better have written their own bytecode verifier already, and maybe a sandbox or two as well.

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