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From: Eduard Zingerman <eddyz87@gmail.com>
To: Haojian Zhuang <haojian.zhuang@linaro.org>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	 John Fastabend <john.fastabend@gmail.com>
Subject: Re: [PATCH] bpf: check mem for dynptr type
Date: Mon, 04 Mar 2024 14:46:06 +0200	[thread overview]
Message-ID: <07f7315efef78b7a19dec16b59b74b15f7b97dd6.camel@gmail.com> (raw)
In-Reply-To: <20240303023732.1390919-1-haojian.zhuang@linaro.org>

On Sun, 2024-03-03 at 02:37 +0000, Haojian Zhuang wrote:
> When user sends message to bpf prog by a user ring buffer, a callback
> in bpf prog should load data from the user ring buffer.
> 
> By default, check_mem_access() doesn't handle the type of
> CONST_PTR_TO_DYNPTR. So verifier reports an invalid memory access issue.
> 
> So add the case of CONST_PTR_TO_DYNPTR type. Make bpf prog to handle
> content in the user ring buffer.
> 

You are referring to bpf_user_ringbuf_drain() helper function, right?
Could you please provide an example of program that fails to verify?
(ideally the patch set should extend
 tools/testing/selftests/bpf/progs/user_ringbuf_success.c
 to make sure that intended use case is tested).


  reply	other threads:[~2024-03-04 12:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-03  2:37 [PATCH] bpf: check mem for dynptr type Haojian Zhuang
2024-03-04 12:46 ` Eduard Zingerman [this message]
2024-03-04 13:02   ` Haojian Zhuang
2024-03-04 13:13     ` Eduard Zingerman
2024-03-04 13:46       ` Haojian Zhuang
2024-03-04 17:08         ` Eduard Zingerman

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