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From:   KP Singh <kpsingh@chromium.org>
Date:   Tue, 24 Mar 2020 02:52:21 +0100
To:     Casey Schaufler <casey@schaufler-ca.com>
Cc:     linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        Brendan Jackman <jackmanb@google.com>,
        Florent Revest <revest@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        James Morris <jmorris@namei.org>,
        Kees Cook <keescook@chromium.org>,
        Paul Turner <pjt@google.com>, Jann Horn <jannh@google.com>,
        Florent Revest <revest@chromium.org>,
        Brendan Jackman <jackmanb@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH bpf-next v5 5/7] bpf: lsm: Initialize the BPF LSM hooks
Message-ID: <20200324015217.GA28487@chromium.org>
References: <20200323164415.12943-1-kpsingh@chromium.org>
 <20200323164415.12943-6-kpsingh@chromium.org>
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On 23-M?r 18:13, Casey Schaufler wrote:
> On 3/23/2020 9:44 AM, KP Singh wrote:
> > From: KP Singh <kpsingh@google.com>
> >
> > The bpf_lsm_ nops are initialized into the LSM framework like any other
> > LSM.  Some LSM hooks do not have 0 as their default return value. The
> > __weak symbol for these hooks is overridden by a corresponding
> > definition in security/bpf/hooks.c
> >
> > +	return 0;

[...]

> > +}
> > +
> > +DEFINE_LSM(bpf) = {
> > +	.name = "bpf",
> > +	.init = bpf_lsm_init,
> 
> Have you given up on the "BPF must be last" requirement?

Yes, we dropped it for as the BPF programs require CAP_SYS_ADMIN
anwyays so the position ~shouldn't~ matter. (based on some of the
discussions we had on the BPF_MODIFY_RETURN patches).

However, This can be added later (in a separate patch) if really
deemed necessary.

- KP

> 
> > +};