On Thu, Sep 11, 2025 at 09:29:35AM +0200, Peter Zijlstra wrote:
> On Wed, Sep 10, 2025 at 08:05:11PM -0700, Kees Cook wrote:
>
> > > > +/* Check if a function needs KCFI preamble generation.
> > > > + ALL functions get preambles when -fsanitize=kcfi is enabled,
> > > > regardless
> > > > + of no_sanitize("kcfi") attribute. */
> > >
> > > Why no_sanitize(“kcfi”) is not considered here?
> >
> > no_sanitize(“kcfi”) is strictly about whether call-site checking
> > is performed within the function. It is not used to mark a function as
> > not being the target of a KCFI call.
>
> I'll once again argue that __attribute__((nocf_check)) (aka. __noendbr)
> should have that effect.
>
> If there is no ENDBR, then no amount of kCFI preamble will make the
> function (indirectly) callable.
Oh yeah, sure! I've added this for v3 now.
--
Kees Cook
