netdev - Re: [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test

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Message-ID: <9b89ac02-de43-10db-816d-4f4888e71a80@fb.com>
Date:   Mon, 7 Feb 2022 09:44:43 -0800
From:   Yonghong Song <yhs@...com>
To:     Stanislav Fomichev <sdf@...gle.com>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>
CC:     <ast@...nel.org>, <daniel@...earbox.net>, <andrii@...nel.org>,
        Lorenzo Bianconi <lorenzo@...nel.org>
Subject: Re: [PATCH bpf-next 2/2] bpf: test_run: fix overflow in
 bpf_test_finish frags parsing



On 2/4/22 3:58 PM, Stanislav Fomichev wrote:
> This place also uses signed min_t and passes this singed int to
> copy_to_user (which accepts unsigned argument). I don't think
> there is an issue, but let's be consistent.
> 
> Cc: Lorenzo Bianconi <lorenzo@...nel.org>
> Fixes: 7855e0db150ad ("bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature")
> Signed-off-by: Stanislav Fomichev <sdf@...gle.com>

Agreed that there is no actual issue as the 'copy_size' should be small 
here (<= maximum skb total packet size). I tried to add 
-Wsign-conversion to kernel compilation and saw tons of warnings. I guess
we have to deal with case by case then.

Acked-by: Yonghong Song <yhs@...com>