Re: [kernel-hardening] [PATCH] arm64: vdso: Mark vDSO code as read-only

[David Brown]

On Thu, Feb 11, 2016 at 03:19:20PM +0100, Ard Biesheuvel wrote:

> > diff --git a/arch/arm64/kernel/vdso/vdso.S b/arch/arm64/kernel/vdso/vdso.S
> > index 60c1db5..db7c0f2 100644
> > --- a/arch/arm64/kernel/vdso/vdso.S
> > +++ b/arch/arm64/kernel/vdso/vdso.S
> > @@ -24,6 +24,7 @@
> >         __PAGE_ALIGNED_DATA
>
> ^^ You can get rid of this now as well

Can we?  The page is getting mapped to userspace, and if we didn't
page align it, we could leak kernel read-only data to every userspace
process.

David