netdev - Re: [PATCH bpf v3 3/7] netdevsim: Add debugfs toggle to reject BPF programs in verifier

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Message-ID: <87pn3jnl3j.fsf@toke.dk>
Date:   Wed, 09 Dec 2020 14:51:44 +0100
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andriin@...com>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Romain Perier <romain.perier@...il.com>,
        Allen Pais <apais@...ux.microsoft.com>,
        Grygorii Strashko <grygorii.strashko@...com>,
        Simon Horman <simon.horman@...ronome.com>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Lorenzo Bianconi <lorenzo@...nel.org>,
        Wei Yongjun <weiyongjun1@...wei.com>,
        Jiri Benc <jbenc@...hat.com>, oss-drivers@...ronome.com,
        linux-omap@...r.kernel.org, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Subject: Re: [PATCH bpf v3 3/7] netdevsim: Add debugfs toggle to reject BPF
 programs in verifier

Toke Høiland-Jørgensen <toke@...hat.com> writes:

> From: Toke Høiland-Jørgensen <toke@...hat.com>
>
> This adds a new debugfs toggle ('bpf_bind_verifier_accept') that can be
> used to make netdevsim reject BPF programs from being accepted by the
> verifier. If this toggle (which defaults to true) is set to false,
> nsim_bpf_verify_insn() will return EOPNOTSUPP on the last
> instruction (after outputting the 'Hello from netdevsim' verifier message).
>
> This makes it possible to check the verification callback in the driver
> from test_offload.py in selftests, since the verifier now clears the
> verifier log on a successful load, hiding the message from the driver.
>
> Fixes: 6f8a57ccf85 ("bpf: Make verifier log more relevant by default")

Ugh, the patchwork bot pointed out that I somehow managed to truncate
the commit ID here; apologies, will send a v4.

-Toke