Re: [PATCH v3 4/9] lsm: framework for BPF integrity verification

Song Liu
2026-03-27T18:25:06Z

On Fri, Mar 27, 2026 at 10:54 AM Blaise Boscaccy
<bboscaccy@linux.microsoft.com> wrote:
>
> Song Liu <song@kernel.org> writes:
>
> > On Wed, Mar 25, 2026 at 11:07 PM Blaise Boscaccy
> > <bboscaccy@linux.microsoft.com> wrote:
> > [...]
> >> The first new callback, bpf_prog_load_integrity(), located within the
> >> security_bpf_prog_load() hook, is necessary to ensure that the integrity
> >> verification callbacks are executed before any of the existing LSMs
> >> are executed via the bpf_prog_load() callback. Reusing the existing
> >> bpf_prog_load() callback for integrity verification could result in LSMs
> >> not having access to the integrity verification results when asked to
> >> authorize the BPF program load in the bpf_prog_load() callback.
> >>
> >> The new LSM hook, security_bpf_prog_load_post_integrity(), is intended
> >> to be called from within LSMs performing BPF program integrity
> >> verification. It is used to report the verdict of the integrity
> >> verification to other LSMs enforcing access control policy on BPF
> >> program loads. LSMs enforcing such access controls should register a
> >> bpf_prog_load_post_integrity() callback to receive integrity verdicts.
> >
> > bpf_prog_load_post_integrity() is weird. Some questions about it:
> >
> > 1. Is it possible to call it from other LSMs (not hornet)? Specifically, is it
> > possible to call it from BPF LSM?
>
> There is nothing hornet exclusive about that security hook. If the BPF
> LSM folks wanted to use it they would probably need to implement a
> kfunc to invoke it.

Please also include the kfunc in v4.

Thanks,
Song