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

On Mon, Oct 02, 2023 at 08:11:41PM +0200, Christian K?nig
wrote:
> 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.
Sounds great; thanks!

-Kees

-- 
Kees Cook

Am 02.10.23 um 20:22 schrieb Kees Cook:
> On Mon, Oct 02, 2023 at 08:11:41PM +0200, Christian K?nig wrote:
>> 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.
> Sounds great; thanks!
I wasn't 100% sure for the VC4 patch, but pushed the whole set to 
drm-misc-next anyway.

This also means that the patches are now auto merged into the drm-tip 
integration branch and should any build or unit test go boom we should 
notice immediately and can revert it pretty easily.

Thanks,
Christian.
>
> -Kees
>