[kernel-hardening] Re: [PATCH v8 1/4] syscalls: Verify address limit before returning to user-mode

Ingo Molnar
2017-04-28T06:33:23Z

* Thomas Garnier <thgarnie@google.com> wrote:

> > BTW., a further simplification would be:
> >
> > #ifndef ADDR_LIMIT_CHECK_PRE
> > # define ADDR_LIMIT_CHECK_PRE ...
> > #endif
> >
> > This way architectures could override this generic functionality simply by
> > defining the helpers. Architectures that don't do that get the generic version.
>
> I don't think architectures need to do that. The optimizations are
> embedding the checks on their architecture-specific code to make it
> faster and remove the size impact. The pre/post is fine for the rest.

Indeed, only the generic code needs to turn off that code - architectures will
place these callbacks elsewhere.

Thanks,

Ingo