Re: [PATCH net 3/3] can: j1939: j1939_tp_cmd_recv(): check the dst address of TP.CM_BAM

From: Oleksij Rempel
Date: Fri Oct 22 2021 - 06:29:13 EST


On Thu, Oct 21, 2021 at 10:04:17PM +0800, Zhang Changzhong wrote:
> The TP.CM_BAM message must be sent to the global address [1], so add a
> check to drop TP.CM_BAM sent to a non-global address.
>
> Without this patch, the receiver will treat the following packets as
> normal RTS/CTS tranport:
> 18EC0102#20090002FF002301
> 18EB0102#0100000000000000
> 18EB0102#020000FFFFFFFFFF
>
> [1] SAE-J1939-82 2015 A.3.3 Row 1.
>
> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
> Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>
> ---
> net/can/j1939/transport.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
> index 2efa606..93ec0c3 100644
> --- a/net/can/j1939/transport.c
> +++ b/net/can/j1939/transport.c
> @@ -2019,6 +2019,8 @@ static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb)
> extd = J1939_ETP;
> fallthrough;
> case J1939_TP_CMD_BAM:
> + if (!j1939_cb_is_broadcast(skcb))

Please add here netdev_err_once("with some message"), we need to know if
some MCU makes bad things.

> + return;
> fallthrough;
> case J1939_TP_CMD_RTS:
> if (skcb->addr.type != extd)
> --
> 2.9.5
>
>

--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |