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Date:   Tue, 25 Jul 2023 20:11:42 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Lin Ma <linma@zju.edu.cn>
Cc:     davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
        ast@kernel.org, martin.lau@kernel.org, yhs@fb.com,
        void@manifault.com, andrii@kernel.org, houtao1@huawei.com,
        inwardvessel@gmail.com, kuniyu@amazon.com, songliubraving@fb.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org
Subject: Re: [PATCH v2] bpf: Add length check for
 SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing
Message-ID: <20230725201142.593ae606@kernel.org>
In-Reply-To: <20230725023330.422856-1-linma@zju.edu.cn>
References: <20230725023330.422856-1-linma@zju.edu.cn>
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On Tue, 25 Jul 2023 10:33:30 +0800 Lin Ma wrote:
> The nla_for_each_nested parsing in function bpf_sk_storage_diag_alloc
> does not check the length of the nested attribute. This can lead to an
> out-of-attribute read and allow a malformed nlattr (e.g., length 0) to
> be viewed as a 4 byte integer.
> 
> This patch adds an additional check when the nlattr is getting counted.
> This makes sure the latter nla_get_u32 can access the attributes with
> the correct length.
> 
> Fixes: 1ed4d92458a9 ("bpf: INET_DIAG support in bpf_sk_storage")
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Lin Ma <linma@zju.edu.cn>

Reviewed-by: Jakub Kicinski <kuba@kernel.org>

Those who parse manually must do checks manually. It is what it is.