Re: [kernel-hardening] Re: [RFC v1] implement SL*B and stack usercopy runtime checks

Vasiliy Kulikov
2011-07-03T19:53:06Z

On Sun, Jul 03, 2011 at 12:37 -0700, Joe Perches wrote:
> On Sun, 2011-07-03 at 23:24 +0400, Vasiliy Kulikov wrote:
> > Btw, if the perfomance will be acceptable, what do you think about
> > logging/reacting on the spotted overflows?
>
> If you do, it might be useful to track the found location(s)

Sure.

> and only emit the overflow log entry once as found.

Hmm, if consider it as a purely debugging feature, then yes. But if
consider it as a try to block some exploitation attempt, then no.
I'd appresiate the latter.

> Maybe use __builtin_return_address(depth) for tracking.

PaX/Grsecurity uses dump_stack() and do_group_exit(SIGKILL); If setup,
it kills all user's processes and locks the user for some time. I don't
really propose the latter, but some reaction (to at least slowdown a
blind bruteforce) might be useful.

Thanks,

--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments