Re: [PATCH v11 00/11] x86: PIE support to extend KASLR randomization

Thomas Garnier
2020-03-03T15:43:47Z

On Tue, Mar 3, 2020 at 1:55 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Mon, Mar 02, 2020 at 09:02:15PM -0800, Kees Cook wrote:
> > On Thu, Feb 27, 2020 at 04:00:45PM -0800, Thomas Garnier wrote:
> > > Minor changes based on feedback and rebase from v10.
> > >
> > > Splitting the previous serie in two. This part contains assembly code
> > > changes required for PIE but without any direct dependencies with the
> > > rest of the patchset.
> > >
> > > Note: Using objtool to detect non-compliant PIE relocations is not yet
> > > possible as this patchset only includes the simplest PIE changes.
> > > Additional changes are needed in kvm, xen and percpu code.
> > >
> > > Changes:
> > > - patch v11 (assembly);
> > > - Fix comments on x86/entry/64.
> > > - Remove KASLR PIE explanation on all commits.
> > > - Add note on objtool not being possible at this stage of the patchset.
> >
> > This moves us closer to PIE in a clean first step. I think these patches
> > look good to go, and unblock the work in kvm, xen, and percpu code. Can
> > one of the x86 maintainers pick this series up?
>
> But,... do we still need this in the light of that fine-grained kaslr
> stuff?
>
> What is the actual value of this PIE crud in the face of that?

If I remember well, it makes it easier/better but I haven't seen a
recent update on that. Is that accurate Kees?