Subject: Re: [PATCH] powerpc/signal32: Use struct_group() to zero spe regs

From: Kees Cook <[email-masked]>
Date: Mon, 22 Nov 2021 12:47:28 -0800

On Mon, Nov 22, 2021 at 04:43:36PM +1100, Michael Ellerman wrote:
> LEROY Christophe <[email-masked]> writes:
> > Le 18/11/2021 à 21:36, Kees Cook a écrit :
> >> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> >> field bounds checking for memset(), avoid intentionally writing across
> >> neighboring fields.
> >> 
> >> Add a struct_group() for the spe registers so that memset() can correctly reason
> >> about the size:
> >> 
> >>     In function 'fortify_memset_chk',
> >>         inlined from 'restore_user_regs.part.0' at arch/powerpc/kernel/signal_32.c:539:3:
> >>     >> include/linux/fortify-string.h:195:4: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> >>       195 |    __write_overflow_field();
> >>           |    ^~~~~~~~~~~~~~~~~~~~~~~~
> >> 
> >> Reported-by: kernel test robot <[email-masked]>
> >> Signed-off-by: Kees Cook <[email-masked]>
> >
> > Reviewed-by: Christophe Leroy <[email-masked]>
> 
> Acked-by: Michael Ellerman <[email-masked]>

Thanks! Should I take this via my tree, or do you want to take it via
ppc?

-Kees

-- 
Kees Cook