Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 28 Oct 2021 10:30:46 +0200
From:   Oleksij Rempel <o.rempel@pengutronix.de>
To:     Zhang Changzhong <zhangchangzhong@huawei.com>
Cc:     Robin van der Gracht <robin@protonic.nl>,
        linux-kernel@vger.kernel.org,
        Oleksij Rempel <linux@rempel-privat.de>,
        netdev@vger.kernel.org, Marc Kleine-Budde <mkl@pengutronix.de>,
        kernel@pengutronix.de, Oliver Hartkopp <socketcan@hartkopp.net>,
        Jakub Kicinski <kuba@kernel.org>, linux-can@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH net 2/3] can: j1939: j1939_can_recv(): ignore messages
 with invalid source address
Message-ID: <20211028083046.GF20681@pengutronix.de>
References: <1634825057-47915-1-git-send-email-zhangchangzhong@huawei.com>
 <1634825057-47915-3-git-send-email-zhangchangzhong@huawei.com>
 <20211022102306.GB20681@pengutronix.de>
 <9c636d7f-70df-18c9-66ed-46eb21f4ffbb@huawei.com>
 <20211028065144.GE20681@pengutronix.de>
 <ff21f8b9-0fe0-e6be-73d4-18b9f5bfd773@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <ff21f8b9-0fe0-e6be-73d4-18b9f5bfd773@huawei.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Precedence: bulk

On Thu, Oct 28, 2021 at 03:33:21PM +0800, Zhang Changzhong wrote:
> On 2021/10/28 14:51, Oleksij Rempel wrote:
> > Hi,
> > 
> > On Mon, Oct 25, 2021 at 03:30:57PM +0800, Zhang Changzhong wrote:
> >> On 2021/10/22 18:23, Oleksij Rempel wrote:
> >>> On Thu, Oct 21, 2021 at 10:04:16PM +0800, Zhang Changzhong wrote:
> >>>> According to SAE-J1939-82 2015 (A.3.6 Row 2), a receiver should never
> >>>> send TP.CM_CTS to the global address, so we can add a check in
> >>>> j1939_can_recv() to drop messages with invalid source address.
> >>>>
> >>>> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
> >>>> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
> >>>
> >>> NACK. This will break Address Claiming, where first message is SA == 0xff
> >>
> >> I know that 0xfe can be used as a source address, but which message has a source
> >> address of 0xff?
> >>
> >> According to SAE-J1939-81 2017 4.2.2.8：
> >>
> >>   The network address 255, also known as the Global address, is permitted in the
> >>   Destination Address field of the SAE J1939 message identifier but never in the
> >>   Source Address field.
> > 
> > You are right. Thx!
> > 
> > Are you using any testing frameworks?
> > Can you please take a look here:
> > https://github.com/linux-can/can-tests/tree/master/j1939
> > 
> > We are using this scripts for regression testing of some know bugs.
> 
> Great! I'll run these scripts before posting patches.
 
You are welcome to extend this tests :)

Regards,
Oleksij
-- 
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 |