[Python-Dev] Include ctypes into core Python?

[Barry Warsaw]

On Wed, 2006-01-11 at 14:54 +0100, Thomas Wouters wrote:
> On Wed, Jan 11, 2006 at 07:59:50AM -0500, Barry Warsaw wrote:
> 
> > BTW, although I'm pretty sure the answer is "no" (at least, I hope it
> > is), is anyone aware of a situation where the mere importation of a
> > module can cause Python to crash?
> 
> Well, I assume you aren't importing any 'hostile' code, nor running in an
> uncontrolled environment so I guess you mean other than running out of
> memory, or the module you are importing actually executing one of the ways
> to crash Python? 

Correct.

> Or the module being an extension module that crashes on
> import? Or another extension module having corrupted the Python environment
> to a point where a simple import crashes Python? Or a non-extension module
> using one of the vulnerabilities (in, say, marshal, or pickle) to corrupt
> the Python environment? Or stuff in os.environ, like LD_* variables, that
> interfere with library linking? Ponder, ponder, no, can't think of any. :)

Let's keep it to modules in the standard library, although that includes
extension modules, and let's further say that it's a controlled enough
environment that you won't have stray evil modules floating around in
your sys.path.

> The pickle vulnerability came up last year, when someone on #python was
> subclassing a builtin type (string or dict, I think the latter) that was
> using a magical invocation of (IIRC) __new__ on unpickle. The subclassed
> __new__ didn't handle this right, so the baseclass __new__ wasn't getting
> called right, and the new object's addressspace was not initialized. This
> lead to crashes. I don't remember the details exactly, and my continuous
> advice of not subclassing builtin types unless you know what you're doing
> solved the issue (there was no actual need to subclass, there), and I have
> no idea whether that specific issue was solved or not, but I'm trying to
> find it again :)

-Barry

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