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Date:   Thu, 9 Jan 2020 19:23:24 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     James Morris <jmorris@namei.org>
Cc:     Stephen Smalley <sds@tycho.nsa.gov>,
        Kees Cook <keescook@chromium.org>,
        KP Singh <kpsingh@chromium.org>,
        Casey Schaufler <casey@schaufler-ca.com>,
        open list <linux-kernel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, linux-security-module@vger.kernel.org,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Thomas Garnier <thgarnie@chromium.org>,
        Michael Halcrow <mhalcrow@google.com>,
        Paul Turner <pjt@google.com>,
        Brendan Gregg <brendan.d.gregg@gmail.com>,
        Jann Horn <jannh@google.com>,
        Matthew Garrett <mjg59@google.com>,
        Christian Brauner <christian@brauner.io>,
        =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@digikod.net>,
        Florent Revest <revest@chromium.org>,
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        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
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        Andrey Ignatov <rdna@fb.com>, Joe Stringer <joe@wand.net.nz>,
        Paul Moore <paul@paul-moore.com>
Subject: Re: [PATCH bpf-next v1 00/13] MAC and Audit policy using eBPF (KRSI)
Message-ID: <20200109182324.GC591973@kroah.com>
References: <20191220154208.15895-1-kpsingh@chromium.org>
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 <c4e6cdf2-1233-fc82-ca01-ba84d218f5aa@tycho.nsa.gov>
 <alpine.LRH.2.21.2001090551000.27794@namei.org>
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On Fri, Jan 10, 2020 at 05:11:38AM +1100, James Morris wrote:
> On Wed, 8 Jan 2020, Stephen Smalley wrote:
> 
> > The cover letter subject line and the Kconfig help text refer to it as a
> > BPF-based "MAC and Audit policy".  It has an enforce config option that
> > enables the bpf programs to deny access, providing access control. IIRC, in
> > the earlier discussion threads, the BPF maintainers suggested that Smack and
> > other LSMs could be entirely re-implemented via it in the future, and that
> > such an implementation would be more optimal.
> 
> In this case, the eBPF code is similar to a kernel module, rather than a 
> loadable policy file.  It's a loadable mechanism, rather than a policy, in 
> my view.
> 
> This would be similar to the difference between iptables rules and 
> loadable eBPF networking code.  I'd be interested to know how the 
> eBPF networking scenarios are handled wrt kernel ABI.

I already know of some people who pre-compile ebpf programs based on a
number of "supported" kernel versions and then load the needed one at
runtime.

Messy, yes, but you are right, ebpf code is much more similiar to a
kernel module than userspace code at the moment.

thanks,

greg k-h