Re: linux-next: Tree for May 14 (objtool 2/2)

From: Kees Cook
Date: Fri May 29 2020 - 15:30:56 EST


On Fri, May 29, 2020 at 12:54:56PM -0500, Josh Poimboeuf wrote:
> On Thu, May 28, 2020 at 11:06:32PM -0700, Kees Cook wrote:
> > diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
> > index 929211039bac..27bcc2568c95 100644
> > --- a/lib/Kconfig.ubsan
> > +++ b/lib/Kconfig.ubsan
> > @@ -63,7 +63,7 @@ config UBSAN_SANITIZE_ALL
> > config UBSAN_ALIGNMENT
> > bool "Enable checks for pointers alignment"
> > default !HAVE_EFFICIENT_UNALIGNED_ACCESS
> > - depends on !X86 || !COMPILE_TEST
> > + depends on !UBSAN_TRAP
> > help
> > This option enables the check of unaligned memory accesses.
> > Enabling this option on architectures that support unaligned
> >
> > How about that?
>
> But I thought you said the alignment traps might be useful on other
> arches? Should it be
>
> depends on !X86 || !UBSAN_TRAP
>
> ?

I was just trying to avoid objtool there, but really, UBSAN_TRAP is
likely insane for unaligned access checks entirely. If anyone ever needs
it, they can adjust. :)

--
Kees Cook