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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sat, 5 Jun 2021 11:17:02 -0700
Message-ID: <CAHk-=wiUVqHN76YUwhkjZzwTdjMMJf_zN4+u7vEJjmEGh3recw@mail.gmail.com>
Subject: Re: [PATCH v2] lockdown,selinux: avoid bogus SELinux lockdown
 permission checks
To:     Casey Schaufler <casey@schaufler-ca.com>
Cc:     Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Paul Moore <paul@paul-moore.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Ondrej Mosnacek <omosnace@redhat.com>,
        LSM List <linux-security-module@vger.kernel.org>,
        James Morris <jmorris@namei.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        SElinux list <selinux@vger.kernel.org>,
        ppc-dev <linuxppc-dev@lists.ozlabs.org>,
        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Jiri Olsa <jolsa@redhat.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
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On Sat, Jun 5, 2021 at 11:11 AM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> You have fallen into a common fallacy. The fact that the "code runs"
> does not assure that the "system works right". In the security world
> we face this all the time, often with performance expectations. In this
> case the BPF design has failed [..]

I think it's the lockdown patches that have failed. They did the wrong
thing, they didn't work,

The report in question is for a regression.

THERE ARE NO VALID ARGUMENTS FOR REGRESSIONS.

Honestly, security people need to understand that "not working" is not
a success case of security. It's a failure case.

Yes, "not working" may be secure. But security in that case is *pointless*.

              Linus