Re: [PATCH 1/2] x86/cfi: Fix ret_from_fork indirect calls

From: Peter Zijlstra
Date: Wed Jun 21 2023 - 14:17:38 EST


On Wed, Jun 21, 2023 at 11:08:46AM -0700, Kees Cook wrote:

> Ah yeah, it should be direct-called only. I keep forgetting about the
> endbr removal pass.
>
> > I can't seem to manage to have it clobber it's __cfi hash value. Ideally
> > we'd have an attribute to force the thing to 0 or something.
>
> Doesn't objtool have logic to figure out this is only ever
> direct-called?

It does; let me also use that same thing to clobber the kCFI hashes for
these functions.