netdev - Re: [net-next v3 0/2] eBPF seccomp filters

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Message-ID: <cda8f13d-79b6-077a-2129-d2d52dc8efd1@oracle.com>
Date:   Tue, 27 Feb 2018 16:22:45 -0500
From:   chris hyser <chris.hyser@...cle.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     Andy Lutomirski <luto@...capital.net>,
        Linux Containers <containers@...ts.linux-foundation.org>,
        Netdev <netdev@...r.kernel.org>, Will Drewry <wad@...omium.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Sargun Dhillon <sargun@...gun.me>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>
Subject: Re: [net-next v3 0/2] eBPF seccomp filters

On 02/27/2018 02:19 PM, Kees Cook wrote:
> On Tue, Feb 27, 2018 at 8:59 AM, chris hyser <chris.hyser@...cle.com> wrote:
>> I will try to find that discussion. As someone pointed out here though, eBPF
> 
> A good starting point might be this:
> https://lwn.net/Articles/441232/

Thanks. A fair amount of reading referenced there :-). In particular I'll be curious to find out what happened to this idea:

"Essentially, that would make for three choices for each system call: enabled, disabled, or filtered."

Something like that might address some of the security concerns in that a simple go/no go on syscall number need not 
incur the performance hit nor increased attack surface of running c/eBPF code, but it is there for argument checking, 
etc if you need it. Basically instead of the kernel making the flexibility/performance/security trade-off in advance, 
you leave it to user code/policy.

Anyway, lest it is not clear :-), I think your instincts on security and eBPF are dead on. At the same time it is 
powerful and useful. So, how to make it optional?

-chrish