Re: [PATCH 2/2] ASLR: add possibility for more fine-grained tweaking

From: Ismail DÃnmez
Date: Thu Feb 07 2008 - 05:32:10 EST


At Thursday 07 February 2008 around 12:23:50 Geert Uytterhoeven wrote:
> On Wed, 6 Feb 2008, Ingo Molnar wrote:
> > @@ -541,6 +541,18 @@ config ELF_CORE
> > ÂÂÂÂÂÂhelp
> > ÂÂÂÂÂÂ ÂEnable support for generating core dumps. Disabling saves about
> > 4k.
> > +config COMPAT_BRK
> > +ÂÂÂÂÂbool "Disable heap randomization"
> > +ÂÂÂÂÂdefault y
> > +ÂÂÂÂÂhelp
> > +ÂÂÂÂÂ ÂRandomizing heap placement makes heap exploits harder, but it
> > +ÂÂÂÂÂ Âalso breaks ancient binaries (including anything libc5 based).
> > +ÂÂÂÂÂ ÂThis option changes the bootup default to heap randomization
> > +ÂÂÂÂÂ Âdisabled, and can be overriden runtime by setting
> > +ÂÂÂÂÂ Â/proc/sys/kernel/randomize_va_space to 2.
> > +
> > +ÂÂÂÂÂ ÂOn non-ancient distros (post-2000 ones) Y is usually a safe
> > choice.
>
> Somehow my belly feeling tells me something is wrong with this
> description...
>
> Ah, a negative option (Y -> disable). ÂSo Y is always safe.
>
> `non-ancient distros' really means `recent distros', and if you have one,
> then _N_ should be a safe choice, too?

This indeed looks wrong. The default should be N and the text should say "On
recent distros (post-2000 ones) N is usually a safe choice".

Regards,
ismail

--
Never learn by your mistakes, if you do you may never dare to try again.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/