Re: A way to prevent buffer overflow exploits?

John D. Hardin (jhardin@wolfenet.com) wrote:
: This has been redirected to comp.compilers from the bugtraq list at the
: suggestion of one of the correspondents. Does anybody here wish to comment
: on the idea that I have proposed, namely: modifying GCC/PGCC/etc. to use a
: second stack or other memory area for storing local variables away from the
: stack where return addresses are stored, as a way to prevent
: smash-the-stack buffer overflow exploits?


Unless gcc had changed a great deal since I last messed with it
(1.40 or so), teaching it any new tricks about the stack are going to
be painful in the extreme. Of course, the C language does not actually
require that there _be_ a stack, let alone one that grows downward
from high memory, contains both locals and return addresses, has
a frame-pointer that points _between_ the locals and the parameters,
(my personal hell was trying to dis-abuse gcc of that notion) and so
forth, but just try to tell gcc that. Yeah, I know about the
#defines, what I also know is that not everything that deals with the
stack pays any attention to them :-) Not that the suggestion would
be impossible, just a whole lotta pain for what gain?


I'd also second the moderators comment:


: [This isn't a band-aid I'd endorse. If you want to fix your programs,
: fix them, or better write them in a language that doesn't have those
: holes. -John]


as I haven't had a stack-smash in ages. Of course, I don't
use gets or scanf...


Mike
| albaugh@agames.com
--

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