From: "Lorenz Bauer" <oss@lmb.io>
To: shaozhengchao <shaozhengchao@huawei.com>,
"Stanislav Fomichev" <sdf@google.com>
Cc: ast@kernel.org, daniel@iogearbox.net, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, yuehaibing@huawei.com
Subject: Re: [PATCH v4,bpf-next] bpf: Don't redirect packets with invalid pkt_len
Date: Tue, 20 Sep 2022 15:42:31 +0100 [thread overview]
Message-ID: <aec8ef40-260c-4ded-b806-d381a3075ff0@www.fastmail.com> (raw)
In-Reply-To: <5a3c5ea9-d557-6070-d778-1092f3c51257@huawei.com>
On Mon, 19 Sep 2022, at 11:55, shaozhengchao wrote:
> Sorry for the delay. I'm busy testing the TC module recently. I'm very
> sorry for the user-space breakage.
>
> The root cause of this problem is that eth_type_trans() is called when
> the protocol type of the SKB is parsed. The len value of the SKB is
> reduced to 0. If the user mode requires that the forwarding succeed, or
> if the MAC header is added again after the MAC header is subtracted,
> is this appropriate?
We don't require forwarding to succeed with a 14 byte input buffer. We also don't look at the MAC header.
I think refusing to forward 0 length packets would be OK. Not 100% certain I understood you correctly, let me know if this helps.
Best
Lorenz
next prev parent reply other threads:[~2022-09-20 14:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-15 11:55 [PATCH v4,bpf-next] bpf: Don't redirect packets with invalid pkt_len Zhengchao Shao
2022-07-15 23:30 ` Stanislav Fomichev
2022-07-19 17:00 ` patchwork-bot+netdevbpf
2022-09-14 11:19 ` Lorenz Bauer
2022-09-17 15:46 ` Stanislav Fomichev
2022-09-19 10:55 ` shaozhengchao
2022-09-20 14:42 ` Lorenz Bauer [this message]
2022-09-21 8:48 ` shaozhengchao
2022-09-21 20:59 ` Stanislav Fomichev
2022-10-13 9:36 ` Lorenz Bauer
2022-10-13 10:44 ` shaozhengchao
2022-10-14 16:29 ` Lorenz Bauer
2022-10-14 16:55 ` sdf
2022-10-15 2:36 ` shaozhengchao
2022-11-03 21:07 ` Martin KaFai Lau
2022-11-03 21:36 ` Stanislav Fomichev
2022-11-03 22:42 ` Martin KaFai Lau
2022-11-03 22:58 ` Stanislav Fomichev
2022-11-09 21:43 ` Stanislav Fomichev
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