Virtualization - Oct 2023 - [PATCH 0/9] drm: Annotate structs with __counted_by

On Mon, Oct 2, 2023 at 5:20?AM Christian K?nig
<ckoenig.leichtzumerken at gmail.com> wrote:
>
> Am 29.09.23 um 21:33 schrieb Kees Cook:
> > On Fri, 22 Sep 2023 10:32:05 -0700, Kees Cook wrote:
> >> This is a batch of patches touching drm for preparing for the
coming
> >> implementation by GCC and Clang of the __counted_by attribute.
Flexible
> >> array members annotated with __counted_by can have their accesses
> >> bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for
array
> >> indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
> >>
> >> As found with Coccinelle[1], add __counted_by to structs that
would
> >> benefit from the annotation.
> >>
> >> [...]
> > Since this got Acks, I figure I should carry it in my tree. Let me
know
> > if this should go via drm instead.
> >
> > Applied to for-next/hardening, thanks!
> >
> > [1/9] drm/amd/pm: Annotate struct smu10_voltage_dependency_table with
__counted_by
> >        https://git.kernel.org/kees/c/a6046ac659d6
>
> STOP! In a follow up discussion Alex and I figured out that this won't
work.
>
> The value in the structure is byte swapped based on some firmware
> endianness which not necessary matches the CPU endianness.
SMU10 is APU only so the endianess of the SMU firmware and the CPU
will always match.

Alex
>
> Please revert that one from going upstream if it's already on it's
way.
>
> And because of those reasons I strongly think that patches like this
> should go through the DRM tree :)
>
> Regards,
> Christian.
>
> > [2/9] drm/amdgpu/discovery: Annotate struct ip_hw_instance with
__counted_by
> >        https://git.kernel.org/kees/c/4df33089b46f
> > [3/9] drm/i915/selftests: Annotate struct perf_series with
__counted_by
> >        https://git.kernel.org/kees/c/ffd3f823bdf6
> > [4/9] drm/msm/dpu: Annotate struct dpu_hw_intr with __counted_by
> >        https://git.kernel.org/kees/c/2de35a989b76
> > [5/9] drm/nouveau/pm: Annotate struct nvkm_perfdom with __counted_by
> >        https://git.kernel.org/kees/c/188aeb08bfaa
> > [6/9] drm/vc4: Annotate struct vc4_perfmon with __counted_by
> >        https://git.kernel.org/kees/c/59a54dc896c3
> > [7/9] drm/virtio: Annotate struct virtio_gpu_object_array with
__counted_by
> >        https://git.kernel.org/kees/c/5cd476de33af
> > [8/9] drm/vmwgfx: Annotate struct vmw_surface_dirty with __counted_by
> >        https://git.kernel.org/kees/c/b426f2e5356a
> > [9/9] drm/v3d: Annotate struct v3d_perfmon with __counted_by
> >        https://git.kernel.org/kees/c/dc662fa1b0e4
> >
> > Take care,
> >
>

On Mon, Oct 02, 2023 at 11:06:19AM -0400, Alex Deucher
wrote:
> On Mon, Oct 2, 2023 at 5:20?AM Christian K?nig
> <ckoenig.leichtzumerken at gmail.com> wrote:
> >
> > Am 29.09.23 um 21:33 schrieb Kees Cook:
> > > On Fri, 22 Sep 2023 10:32:05 -0700, Kees Cook wrote:
> > >> This is a batch of patches touching drm for preparing for the
coming
> > >> implementation by GCC and Clang of the __counted_by
attribute. Flexible
> > >> array members annotated with __counted_by can have their
accesses
> > >> bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array
> > >> indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
> > >>
> > >> As found with Coccinelle[1], add __counted_by to structs that
would
> > >> benefit from the annotation.
> > >>
> > >> [...]
> > > Since this got Acks, I figure I should carry it in my tree. Let
me know
> > > if this should go via drm instead.
> > >
> > > Applied to for-next/hardening, thanks!
> > >
> > > [1/9] drm/amd/pm: Annotate struct smu10_voltage_dependency_table
with __counted_by
> > >        https://git.kernel.org/kees/c/a6046ac659d6
> >
> > STOP! In a follow up discussion Alex and I figured out that this
won't work.
I'm so confused; from the discussion I saw that Alex said both instances
were false positives?
> >
> > The value in the structure is byte swapped based on some firmware
> > endianness which not necessary matches the CPU endianness.
> 
> SMU10 is APU only so the endianess of the SMU firmware and the CPU
> will always match.
Which I think is what is being said here?
> > Please revert that one from going upstream if it's already on
it's way.
> >
> > And because of those reasons I strongly think that patches like this
> > should go through the DRM tree :)
Sure, that's fine -- please let me know. It was others Acked/etc. Who
should carry these patches?

Thanks!

-Kees

> >
> > Regards,
> > Christian.
> >
> > > [2/9] drm/amdgpu/discovery: Annotate struct ip_hw_instance with
__counted_by
> > >        https://git.kernel.org/kees/c/4df33089b46f
> > > [3/9] drm/i915/selftests: Annotate struct perf_series with
__counted_by
> > >        https://git.kernel.org/kees/c/ffd3f823bdf6
> > > [4/9] drm/msm/dpu: Annotate struct dpu_hw_intr with __counted_by
> > >        https://git.kernel.org/kees/c/2de35a989b76
> > > [5/9] drm/nouveau/pm: Annotate struct nvkm_perfdom with
__counted_by
> > >        https://git.kernel.org/kees/c/188aeb08bfaa
> > > [6/9] drm/vc4: Annotate struct vc4_perfmon with __counted_by
> > >        https://git.kernel.org/kees/c/59a54dc896c3
> > > [7/9] drm/virtio: Annotate struct virtio_gpu_object_array with
__counted_by
> > >        https://git.kernel.org/kees/c/5cd476de33af
> > > [8/9] drm/vmwgfx: Annotate struct vmw_surface_dirty with
__counted_by
> > >        https://git.kernel.org/kees/c/b426f2e5356a
> > > [9/9] drm/v3d: Annotate struct v3d_perfmon with __counted_by
> > >        https://git.kernel.org/kees/c/dc662fa1b0e4
> > >
> > > Take care,
> > >
> >
-- 
Kees Cook