Re: [PATCH] media: nxp: isi: Check whether pad is non-NULL before access

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thu, Jan 11, 2024 at 05:49:41PM +0000, Kieran Bingham wrote:
> Quoting Laurent Pinchart (2023-12-03 16:59:59)
> > Hi Marek,
> > 
> > Thank you for the patch.
> > 
> > On Fri, Dec 01, 2023 at 04:06:04PM +0100, Marek Vasut wrote:
> > > The pad can be NULL if media controller routing is not set up correctly.
> > > Check whether the pad is NULL before using it, otherwise it is possible
> > > to achieve NULL pointer dereference.
> > 
> > Could you share more information about how to misconfigure the routing ?
> 
> You simply do 'nothing'.

The default configuration should be working one. I think that should
then be fixed too (in a separate patch).

> > > Fixes: cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")
> > > Signed-off-by: Marek Vasut <marex@denx.de>
> > > ---
> > > Cc: Fabio Estevam <festevam@gmail.com>
> > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> > > Cc: NXP Linux Team <linux-imx@nxp.com>
> > > Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
> > > Cc: Sascha Hauer <s.hauer@pengutronix.de>
> > > Cc: Shawn Guo <shawnguo@kernel.org>
> > > Cc: linux-arm-kernel@lists.infradead.org
> > > Cc: linux-media@vger.kernel.org
> > > ---
> > >  drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c | 8 +++++++-
> > >  1 file changed, 7 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c
> > > index 792f031e032ae..44354931cf8a1 100644
> > > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c
> > > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c
> > > @@ -160,8 +160,14 @@ mxc_isi_crossbar_xlate_streams(struct mxc_isi_crossbar *xbar,
> > >       }
> > >  
> > >       pad = media_pad_remote_pad_first(&xbar->pads[sink_pad]);
> > > -     sd = media_entity_to_v4l2_subdev(pad->entity);
> > > +     if (!pad) {
> > > +             dev_dbg(xbar->isi->dev,
> > > +                     "no pad connected to crossbar input %u\n",
> > > +                     sink_pad);
> > > +             return ERR_PTR(-EPIPE);
> > > +     }
> > >  
> > > +     sd = media_entity_to_v4l2_subdev(pad->entity);
> > >       if (!sd) {
> > >               dev_dbg(xbar->isi->dev,
> > >                       "no entity connected to crossbar input %u\n",
> > 
> > -- 
> > Regards,
> > 
> > Laurent Pinchart

-- 
Regards,

Laurent Pinchart