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From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date: Mon, 20 May 2024 16:48:25 -0400
Message-ID: <CABBYNZJy7jdo0TP768ONje_shZiHtod+sBau7FbvDBXmTWN35Q@mail.gmail.com>
Subject: Re: [PATCH v1] Bluetooth: L2CAP: Fix rejecting L2CAP_CONN_PARAM_UPDATE_REQ
To: linux-bluetooth@vger.kernel.org
Cc: kai.heng.feng@canonical.com
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Hi Kai,

On Mon, May 20, 2024 at 4:10=E2=80=AFPM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>
> This removes the bogus check for max > hcon->le_conn_max_interval since
> the later is just the initial maximum conn interval not the maximum the
> stack could support which is really 3200=3D4000ms.
>
> In order to pass GAP/CONN/CPUP/BV-05-C one shall probably enter values
> of the following fields in IXIT that would cause hci_check_conn_params
> to fail:
>
> TSPX_conn_update_int_min
> TSPX_conn_update_int_max
> TSPX_conn_update_peripheral_latency
> TSPX_conn_update_supervision_timeout
>
> Link: https://github.com/bluez/bluez/issues/847
> Fixes: e4b019515f95 ("Bluetooth: Enforce validation on max value of conne=
ction interval")
> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> ---
>  net/bluetooth/l2cap_core.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 5b509b767557..c49e0d4b3c0d 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -4647,13 +4647,7 @@ static inline int l2cap_conn_param_update_req(stru=
ct l2cap_conn *conn,
>
>         memset(&rsp, 0, sizeof(rsp));
>
> -       if (max > hcon->le_conn_max_interval) {
> -               BT_DBG("requested connection interval exceeds current bou=
nds.");
> -               err =3D -EINVAL;
> -       } else {
> -               err =3D hci_check_conn_params(min, max, latency, to_multi=
plier);
> -       }
> -
> +       err =3D hci_check_conn_params(min, max, latency, to_multiplier);
>         if (err)
>                 rsp.result =3D cpu_to_le16(L2CAP_CONN_PARAM_REJECTED);
>         else
> --
> 2.45.1

I hope that doesn't break the testing you have done, you should really
be setting the invalid values with use of the fields about and not use
hcon->le_conn_max_interval as upper limit of the stack, for more
details check the discussion at
https://github.com/bluez/bluez/issues/847.

--=20
Luiz Augusto von Dentz