* Borislav Petkov <b...@alien8.de> wrote:
> On Fri, Oct 02, 2015 at 09:26:44AM +0200, Ingo Molnar wrote:
> > It's better to generate a WARN()ing programmatically if the W+X condition
> > occurs,
> > that gets noticed by tools and people alike. I'd like to start treating
> > that
> > condition as a hard kernel bug.
> >
> > A dump in dmesg is subject to random noise by printk crusaders and is also
> > subject
> > to general bitrot, nor does it provide any ready warning to act upon.
>
> You're not going to enable this option in production anyway. [...]
Why not? I'd suggest distros do it too, it's not too much code to run during
bootup. That way if we one some weird configuration forget about a W+X mapping,
the distro is warned that there's a security problem.
> > I'd even add this debug check as default-enabled in the x86 defconfigs, so
> > that my own continuous kernel testing kit picks up any new warnings from it.
>
> There's the problem with exposing sensitive info in debugfs if you do that.
> And
> nowadays we're trying hard not to leak any of that.
Ah, I think you missed the following detail: the patch I suggested would
separate
the debugfs bits from the checking bits and would thus allow a 'security check
only' .config setting.
Distros would normally not want to enable the debugfs file, agreed about that.
Thanks,
Ingo
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