netdev - Re: [PATCH bpf-next v8 11/11] selftests/bpf: verify lsm

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Message-ID: <CAKH8qBs6Wz+vukFomy7LEyohzM6mumsrgRRcyfy-0J_8drJ3ZQ@mail.gmail.com>
Date:   Thu, 2 Jun 2022 18:59:47 -0700
From:   Stanislav Fomichev <sdf@...gle.com>
To:     Martin KaFai Lau <kafai@...com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org, ast@...nel.org,
        daniel@...earbox.net, andrii@...nel.org
Subject: Re: [PATCH bpf-next v8 11/11] selftests/bpf: verify lsm_cgroup struct
 sock access

On Thu, Jun 2, 2022 at 6:52 PM Martin KaFai Lau <kafai@...com> wrote:
>
> On Wed, Jun 01, 2022 at 12:02:18PM -0700, Stanislav Fomichev wrote:
> > sk_priority & sk_mark are writable, the rest is readonly.
> >
> > One interesting thing here is that the verifier doesn't
> > really force me to add NULL checks anywhere :-/
> Are you aware if it is possible to get a NULL sk from some of the
> bpf_lsm hooks ?

No, I don't think it's relevant for lsm hooks. I'm more concerned
about fentry/fexit which supposedly should go through the same
verifier path and can be attached everywhere?