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Date:   Thu, 12 May 2022 09:58:08 +0200
From:   Marc Kleine-Budde <mkl@pengutronix.de>
To:     Oliver Hartkopp <socketcan@hartkopp.net>
Cc:     Oleksij Rempel <o.rempel@pengutronix.de>,
        Wolfgang Grandegger <wg@grandegger.com>,
        Devid Antonio Filoni <devid.filoni@egluetechnologies.com>,
        kernel@pengutronix.de, linux-can@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        David Jander <david@protonic.nl>
Subject: Re: [PATCH 1/1] can: skb: add and set local_origin flag
Message-ID: <20220512075808.urlptf4d3wiu4kwh@pengutronix.de>
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On 12.05.2022 08:23:26, Oliver Hartkopp wrote:
> > > > > BTW: There is a bug with interfaces that don't support IFF_ECHO.
> > > > >=20
> > > > > Assume an invalid CAN frame is passed to can_send() on an
> > > > > interface that doesn't support IFF_ECHO. The above mentioned
> > > > > code does happily generate an echo frame and it's send, even
> > > > > if the driver drops it, due to can_dropped_invalid_skb(dev,
> > > > > skb).
> > > > >=20
> > > > > The echoed back CAN frame is treated in raw_rcv() as if the
> > > > > headroom is valid:

> I double checked that code and when I didn't miss anything all the callers
> of can_send() (e.g. raw_sendmsg()) are creating valid skbs.

ACK - I haven't checked, but I assume that all current callers of
can_send() are sound, this I why I started the description with: "Assume
an invalid CAN frame is passed to can_send()". But we can argue that we
trust all callers.

regards,
Marc

--=20
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
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