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From: Florian Westphal <fw@strlen.de>
To: bot+bpf-ci@kernel.org
Cc: bpf@vger.kernel.org, andrii@kernel.org, eddyz87@gmail.com,
	ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org,
	yonghong.song@linux.dev, mason@kernel.org,
	ihor.solodrai@linux.dev
Subject: Re: [PATCH bpf] selftests/bpf: Add tests to assert that netfilter progs cannot write to skb
Date: Wed, 2 Sep 2026 11:00:58 +0200	[thread overview]
Message-ID: <apflyjoO0S-9XuUE@strlen.de> (raw)
In-Reply-To: <da1f216ffd5f1f1102cb82245064b6f60f6e893f6a2e6cb46983206195f49c75@mail.kernel.org>

bot+bpf-ci@kernel.org <bot+bpf-ci@kernel.org> wrote:
> >     Assert that bpf netfilter program type exposes readonly access to the
> >     skb, either via direct packet access or via dynptr API.

> This isn't a bug, but since netfilter progs have no direct packet access,
> would it be clearer to describe this case as writing through ctx->skb (BTF
> walk) instead of 'direct packet access'? The test (ctx->skb->data[0] = 0)
> walks a BTF pointer, which is why the expected message is 'cannot write
> into rdonly_untrusted_mem' rather than a packet-access error.

I'll shorten this to:

"Assert that bpf netfilter programs do not allow skb write access."

I'll also follow the other suggested changes to function names.

      reply	other threads:[~2026-09-02  9:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-02  6:52 [PATCH bpf] selftests/bpf: Add tests to assert that netfilter progs cannot write to skb Florian Westphal
2026-09-02  7:41 ` bot+bpf-ci
2026-09-02  9:00   ` Florian Westphal [this message]

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