[PATCH bpf-next v10 5/5] bpf: Only enable BPF LSM hooks when an LSM program is attached

[KP Singh]

On Fri, May 10, 2024 at 7:23 AM KP Singh <kpsingh at kernel.org> wrote:
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>
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> > On 9 May 2024, at 16:24, Paul Moore <paul at paul-moore.com> wrote:
> >
> > On Wed, May 8, 2024 at 3:00 AM KP Singh <kpsingh at kernel.org> wrote:
> >> One idea here is that only LSM hooks with default_state = false can be toggled.
> >>
> >> This would also any ROPs that try to abuse this function. Maybe we can call "default_disabled" .toggleable (or dynamic)
> >>
> >> and change the corresponding LSM_INIT_TOGGLEABLE. Kees, Paul, this may be a fair middle ground?
> >
> > Seems reasonable to me, although I think it's worth respinning to get
> > a proper look at it in context.  Some naming bikeshedding below ...
> >
> >> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> >> index 4bd1d47bb9dc..5c0918ed6b80 100644
> >> --- a/include/linux/lsm_hooks.h
> >> +++ b/include/linux/lsm_hooks.h
> >> @@ -117,7 +117,7 @@ struct security_hook_list {
> >>        struct lsm_static_call  *scalls;
> >>        union security_list_options     hook;
> >>        const struct lsm_id             *lsmid;
> >> -       bool                            default_enabled;
> >> +       bool                            toggleable;
> >> } __randomize_layout;
> >
> > How about inverting the boolean and using something like 'fixed'
> > instead of 'toggleable'?
> >
>
> I would prefer not changing the all the other LSM_HOOK_INIT calls as we change the default behaviour then. How about calling it "dynamic"
>
> LSM_HOOK_INIT_DYNAMIC and call the boolean dynamic
>

Paul, others, any preferences here?

- KP

> - KP
>
> > --
> > paul-moore.com
>