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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Mon, 14 Nov 2022 14:05:24 -0800
Message-ID: <CABBYNZJ-BjuUcriLpNzs95SDqXP+_6-LJZ-t_00Q6ppy8qYg2Q@mail.gmail.com>
Subject: Re: L2CAP: Spec violation
To:     Sungwoo Kim <iam@sung-woo.kim>
Cc:     marcel@holtmann.org, johan.hedberg@gmail.com, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Hi Kim,

On Fri, Nov 4, 2022 at 9:13 AM Sungwoo Kim <iam@sung-woo.kim> wrote:
>
> Hello,
>
> Our fuzzer found a BT spec violation, illegal state transition on L2cap.
> Specifically, l2cap_chan::state is transitioned from BT_CONFIG to
> BT_DISCONN by CONFIG_RSP by following trace:
>
> l2cap_config_rsp l2cap_core.c:4498
> l2cap_send_disconn_req l2cap_core.c:4585
> l2cap_state_change l2cap_core.c:1618
>
> According to the spec 5.3 vol.3 part A 6.1.4, CONFIG_RSP cannot cause
> that transition, i.e., CONFIG -> DISCONN by CONFIG_RSP is illegal.
> It'd be great if we could discuss.

Can you include some btmon traces?


-- 
Luiz Augusto von Dentz