Re: [patch] Add basic sanity checks to the syscall execution patch

[pageexec]

On 5 Sep 2008 at 20:14, Benjamin Herrenschmidt wrote:

> On Fri, 2008-09-05 at 11:43 +0200, pageexec@xxxxxxxxxxx wrote:
> > > I'd have considered taking your email serious if you had left out the
> > > uncalled and unneeded sarcasm line at the end.
> > 
> > consider how your whole patch is based on one big self-contradiction.
> > you already assume that the attacker *can* modify arbitrary kernel memory
> > (even the otherwise *read-only* syscall table at that), but at the very
> > same time you're saying he *can't* use the same powers to patch out your
> > 'protection' or do many other things to evade it. as it is, it's cargo cult
> > security at its best, reminding one on the Vista kernel's similar 'protection' 
> > mechanism for the service descriptor tables...
> 
> Well, I see it a different way ... it will once for all screw up
> binary modules that try to add syscalls :-)

and that'd be because at the same time they patch the syscall table (remember,
they already have to go to length to get around the read-only pages), they
can't also patch this 'protection'? sounds really plausible, right :).

[fixed hpa's address, .org bounces.]

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