Re: OS stopping stack buffer overflow exploits

From: Gisle S{lensminde (gisle@ii.uib.no)
Date: Sun Jun 04 2000 - 11:58:58 EST


On 4 Jun 2000, Florian Weimer wrote:

> ingo.oeser@informatik.tu-chemnitz.de (Ingo Oeser) writes:
>
> > No code shown either. And no reason deployed, why we couldn't
> > code this without trampolines in the old threads.
>

[Ada-code generating trampolines sniped]

>
> Although the Unrestricted_Access attribute is a GNAT extension, you
> get the idea, I think. (In fact, Unrestricted_Access is expected
> to give you a standard subprogram access value, and I don't think
> there other ways to achieve that, at least they aren't as efficient as
> trampolines.)

I trampolines is forbidden, You wouldn't even manage to compile the
code, as the compiler (GNAT) use nested function in the parser source,
and the compiler itself would crash. The C frontend is saved only
because nested functions is a gnu extension, and the gcc have only
standard C code in it. Nested functions is standard in Ada.
There are however C _programs_ that will break, but I don't know how
many.

--
Gisle Sælensminde ( gisle@ii.uib.no )   

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