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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 3 Mar 2022 14:39:35 -0800
Message-ID: <CAADnVQKfh3Z1DXJ3PEjFheQWEDFOKQjuyx+pkvqe6MXEmo7YHQ@mail.gmail.com>
Subject: Re: [PATCH v3 0/9] bpf-lsm: Extend interoperability with IMA
To:     Mimi Zohar <zohar@linux.ibm.com>
Cc:     KP Singh <kpsingh@kernel.org>,
        Roberto Sassu <roberto.sassu@huawei.com>,
        Shuah Khan <shuah@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Yonghong Song <yhs@fb.com>,
        Florent Revest <revest@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-integrity <linux-integrity@vger.kernel.org>,
        LSM List <linux-security-module@vger.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Florent Revest <revest@google.com>,
        Kees Cook <keescook@chromium.org>
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On Thu, Mar 3, 2022 at 11:13 AM Mimi Zohar <zohar@linux.ibm.com> wrote:
>
> On Thu, 2022-03-03 at 19:14 +0100, KP Singh wrote:
> >
> > Even Robert's use case is to implement IMA policies in BPF this is still
> > fundamentally different from IMA doing integrity measurement for BPF
> > and blocking this patch-set on the latter does not seem rational and
> > I don't see how implementing integrity for BPF would avoid your
> > concerns.
>
> eBPF modules are an entire class of files currently not being measured,
> audited, or appraised.  This is an integrity gap that needs to be
> closed.  The purpose would be to at least measure and verify the
> integrity of the eBPF module that is going to be used in lieu of
> traditional IMA.

Mimi,

. There is no such thing as "eBPF modules". There are BPF programs.
They cannot be signed the same way as kernel modules.
We've been working on providing a way to sign them for more
than a year now. That work is still ongoing.

. IMA cannot be used for integrity check of BPF programs for the same
reasons why kernel module like signing cannot be used.

. This patch set is orthogonal.