netdev - Re: [PATCH] bpf: validate bpf_func when BPF

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Date:   Fri, 13 Sep 2019 14:19:26 +0200
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Sami Tolvanen <samitolvanen@...gle.com>
Cc:     Björn Töpel <bjorn.topel@...el.com>,
        Yonghong Song <yhs@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Kees Cook <keescook@...omium.org>, Martin Lau <kafai@...com>,
        Song Liu <songliubraving@...com>,
        "netdev\@vger.kernel.org" <netdev@...r.kernel.org>,
        "bpf\@vger.kernel.org" <bpf@...r.kernel.org>,
        "linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org>,
        Jesper Dangaard Brouer <brouer@...hat.com>
Subject: Re: [PATCH] bpf: validate bpf_func when BPF_JIT is enabled

Sami Tolvanen <samitolvanen@...gle.com> writes:

> On Thu, Sep 12, 2019 at 3:52 AM Toke Høiland-Jørgensen <toke@...hat.com> wrote:
>> I think it would be good if you do both. I'm a bit worried that XDP
>> performance will end up in a "death by a thousand paper cuts" situation,
>> so I'd rather push back on even relatively small overheads like this; so
>> being able to turn it off in the config would be good.
>
> OK, thanks for the feedback. In that case, I think it's probably
> better to wait until we have CFI ready for upstreaming and use the
> same config for this one.

SGTM, thanks!

>> Can you share more details about what the "future CFI checking" is
>> likely to look like?
>
> Sure, I posted an overview of CFI and what we're doing in Pixel devices here:
>
> https://android-developers.googleblog.com/2018/10/control-flow-integrity-in-android-kernel.html

Great, thank you.

-Toke