From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Borkmann <dborkman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH RFC net-next 08/14] bpf: add eBPF verifier
Date: Tue, 01 Jul 2014 10:05:04 +0200
Message-ID: <53B26BB0.90209@redhat.com>
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To: Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
Cc: "David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>, Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>, Chema Gonzalez <chema-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Eric Dumazet <edumazet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>, Arnaldo Carvalho de Melo <acme-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Jiri Olsa <jolsa-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
List-Id: linux-api@vger.kernel.org

On 06/28/2014 02:06 AM, Alexei Starovoitov wrote:
> Safety of eBPF programs is statically determined by the verifier, which detects:
> - loops
> - out of range jumps
> - unreachable instructions
> - invalid instructions
> - uninitialized register access
> - uninitialized stack access
> - misaligned stack access
> - out of range stack access
> - invalid calling convention
...
> More details in Documentation/networking/filter.txt
>
> Signed-off-by: Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
> ---
...
>   kernel/bpf/verifier.c               | 1431 +++++++++++++++++++++++++++++++++++

Looking at classic BPF verifier which checks safety of BPF
user space programs, it's roughly 200 loc. :-/

> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> new file mode 100644
...
> +#define _(OP) ({ int ret = OP; if (ret < 0) return ret; })
...
> +	_(get_map_info(env, map_id, &map));
...
> +	_(size = bpf_size_to_bytes(bpf_size));

Nit: such macros should be removed, please.