Re: [PATCH] Protection for exploiting null dereference using mmap

From: Pavel Machek
Date: Fri Jun 08 2007 - 11:12:19 EST


Hi!

> > While I understand, there are a few users who will have problems with
> > this default are we really better to not provide this defense in depth
> > for the majority of users and let those with problems turn it off rather
> > than provide no defense by default? I could even provide a different
> > default for SELinux and non-SELinux if anyone saw value in that? But if
> > others think that off default is best I'll send another patch shortly
> > with the unsigned long fix and the default set to 0. My hope is then
> > that distros will figure out to turn this on.
> >
>
> I hope not. This breaks any hardware virtualizer.
>
> So yes, we're better off not having this on, and require it to be
> explicitly enabled by the end user.

You could do something like 4G+4G patches.... but performance penalty
would be ugly.

But no, we cant break userspace 'by default'.
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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