Date:   Fri, 3 Dec 2021 11:29:07 +0100
From:   Johan Hovold <johan@kernel.org>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     Kieran Bingham <kieran.bingham@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] media: uvcvideo: fix division by zero at stream start
Message-ID: <Yanxc/229JFkuP/v@hovoldconsulting.com>
References: <20211026095511.26673-1-johan@kernel.org>
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 <YXfvXzgnvPVqwqZs@hovoldconsulting.com>
 <YXh4NqnpzOnPiA5/@pendragon.ideasonboard.com>
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Precedence: bulk

Hi Laurent,

On Wed, Oct 27, 2021 at 12:50:46AM +0300, Laurent Pinchart wrote:
> Hi Johan,
> 
> On Tue, Oct 26, 2021 at 02:06:55PM +0200, Johan Hovold wrote:
> > On Tue, Oct 26, 2021 at 02:15:20PM +0300, Laurent Pinchart wrote:
> > > On Tue, Oct 26, 2021 at 11:55:05AM +0100, Kieran Bingham wrote:
> > > > Quoting Johan Hovold (2021-10-26 10:55:11)
> > > > > Add the missing bulk-endpoint max-packet sanity check to probe() to
> > > > > avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> > > > > device has broken descriptors (or when doing descriptor fuzz testing).
> > > > > 
> > > > > Note that USB core will reject URBs submitted for endpoints with zero
> > > > > wMaxPacketSize but that drivers doing packet-size calculations still
> > > > > need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> > > > > endpoint descriptors with maxpacket=0")).
> > > > > 
> > > > > Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> > > > > Cc: stable@vger.kernel.org      # 2.6.26
> > > > > Signed-off-by: Johan Hovold <johan@kernel.org>

> > Note however the copy-paste error in the commit message mentioning
> > probe(), which is indeed where this would typically be handled.
> > 
> > Do you want me to resend or can you change
> > 
> > 	s/probe()/uvc_video_start_transfer()/
> > 
> > in the commit message when applying if you think this is acceptable as
> > is?
> 
> I can fix this when applying.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

I noticed that this one hasn't showed up in linux-next yet. Do you still
have it in your queue or do you want me to resend?

Johan