Re: OS stopping stack buffer overflow exploits

Date: Sun Jun 04 2000 - 09:43:02 EST

"Peter T. Breuer" <> writes:

> "A month of sundays ago wrote:"
> > "Peter T. Breuer" <> writes:
> > > And I have no idea why they should want to: nesting is purely a
> > > question of namespaces and syntactic scoping. It should impact
> > > the implementation semantics not at all.
> >
> > GCC use lexical scoping for nested function, lexical scoping use
> > trampolines... so it will break...
> This is goobledegook. Lexical scoping is precisely what I was referring
> to by "a question of namespaces and syntactic scoping". It's a parsing
> detail, or a compiler detail, _not_ an implementation strategy. There
> is no more need to invoke a special implementation strategy for nested
> functions than there is to invoke one for nested blocks.

right, but having to remake the nested function implementation is not
a good idea, especially to implement stuff like non executable stack.

( Read the 'Proposal LUID' thread )

> > [snip]
> > GNU CC implements taking the address of a nested function using a
> > technique called "trampolines". A paper describing them is available
> > as `'
> > [snip]
> Thanks. Looked at it once, and it was incomprehensible then. Glad
> to say I've forgotten it entirely since. Do they have an ascii version?
> Interestingly, I get a 404 from the address you give above. The
> homepage surrounding it says:

sorry, it was just a snapshot of the gcc info page,
the interesting stuff in it was above the url.

		-- Yoann
 It is well known that M$ product don't make a free() after a malloc(),
the unix community wish them good luck for their future developement.

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