[RFC PATCH 06/20] bpf: lsm: Add Landlock kfuncs

[Paul Moore]

On Wed, Jul 1, 2026 at 6:59 AM Mickaël Salaün <mic at digikod.net> wrote:
> On Tue, Apr 07, 2026 at 04:01:28PM -0400, Justin Suess wrote:
> > Create 2 kfuncs exposing control over Landlock functionality to BPF
> > callers. Export an opaque struct bpf_landlock_ruleset preventing callers
> > from accessing unstable internal Landlock fields.

Generally speaking we don't want to provide APIs, either in-kernel or
at the userspace/kernel boundary, that are specific to a single LSM,
see the LSM syscalls or the security_current_getlsmprop_subj()
function as examples.

Yes, Landlock does have its own syscalls, but those are
"grandfathered" and not something I want to see emulated across other
LSMs.  If a BPF program wants to interact with a LSM, it should go
through a LSM framework API.

There have been some initial efforts to develop a LSM wide policy API
for userspace, and while it was put on hold to sort out some namespace
issues, we could move forward with an in-kernel API now.  We don't
have strict API stability guarantees for LSM hooks/APIs so we have
some more freedom to do something now, even if it isn't perfect, and
refine it at a later date.

-- 
paul-moore.com