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

On Mon, Oct 02, 2023 at 08:01:57PM +0200, Christian K?nig
wrote:
> Am 02.10.23 um 18:53 schrieb Kees Cook:
> > 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?
> 
> Probably best if the relevant maintainer pick them up individually.
> 
> Some of those structures are filled in by firmware/hardware and only the
> maintainers can judge if that value actually matches what the compiler
> needs.
> 
> We have cases where individual bits are used as flags or when the size is
> byte swapped etc...
> 
> Even Alex and I didn't immediately say how and where that field is
actually
> used and had to dig that up. That's where the confusion came from.
Okay, I've dropped them all from my tree. Several had Acks/Reviews, so
hopefully those can get picked up for the DRM tree?

Thanks!

-Kees

-- 
Kees Cook

Am 02.10.23 um 20:08 schrieb Kees Cook:
> On Mon, Oct 02, 2023 at 08:01:57PM +0200, Christian K?nig wrote:
>> Am 02.10.23 um 18:53 schrieb Kees Cook:
>>> 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?
>> Probably best if the relevant maintainer pick them up individually.
>>
>> Some of those structures are filled in by firmware/hardware and only
the
>> maintainers can judge if that value actually matches what the compiler
>> needs.
>>
>> We have cases where individual bits are used as flags or when the size
is
>> byte swapped etc...
>>
>> Even Alex and I didn't immediately say how and where that field is
actually
>> used and had to dig that up. That's where the confusion came from.
> Okay, I've dropped them all from my tree. Several had Acks/Reviews, so
> hopefully those can get picked up for the DRM tree?
I will pick those up to go through drm-misc-next.

Going to ping maintainers once more when I'm not sure if stuff is 
correct or not.

Christian.
>
> Thanks!
>
> -Kees
>