Re: [PATCH] [media] tvp686x: Don't go past array

[Mauro Carvalho Chehab <mchehab@osg.samsung.com>]

Em Mon, 25 Apr 2016 14:42:31 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:


> > So, I would go to the following enclosed patch.  
> 
> Looks good to me. Acked below. Amazing how many bugs one can make in one
> simple patch...

Applied, thanks!

Yeah, simple patches are harder than complex ones ;)

> 
> > 
> > Ezequiel,
> > 
> > Btw, I'm not seeing support for fps != 25 (or 30 fps) on this driver.
> > As the device seems to support setting the fps, you should be adding
> > support on it for VIDIOC_S_PARM and VIDIOC_G_PARM.
> > 
> > On both ioctls, the driver should return the actual framerate used.
> > So, you'll need to add a code that would convert from the 15 possible
> > framerate converter register settings to v4l2_fract.
> >   
> >>  
> >>> +			i = 14;		/* 25 fps */
> >>> +		else
> >>> +			i = std_625_50[fps];
> >>> +	} else {
> >>> +		if (unlikely(i > ARRAY_SIZE(std_525_60)))
> >>> +			i = 0;		/* 30 fps */
> >>> +		else
> >>> +			i = std_525_60[fps];
> >>> +	}
> >>>  
> >>>  	return map[i];
> >>>  }
> >>>     
> >>
> >> Regards,
> >>
> >> 	Hans  
> > 
> > Thanks,
> > Mauro
> > 
> > -
> > 
> > [media] tw686x: Don't go past array
> > 
> > Depending on the compiler version, currently it produces the
> > following warnings:
> > 	tw686x-video.c: In function 'tw686x_video_init':
> > 	tw686x-video.c:65:543: warning: array subscript is above array bounds [-Warray-bounds]
> > 
> > This is actually bogus with the current code, as it currently
> > hardcodes the framerate to 30 frames/sec, however a potential
> > use after the array size could happen when the driver adds support
> > for setting the framerate. So, fix it.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>  
> 
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> 
> > 
> > diff --git a/drivers/media/pci/tw686x/tw686x-video.c b/drivers/media/pci/tw686x/tw686x-video.c
> > index 118e9fac9f28..9468fda69f3d 100644
> > --- a/drivers/media/pci/tw686x/tw686x-video.c
> > +++ b/drivers/media/pci/tw686x/tw686x-video.c
> > @@ -61,8 +61,17 @@ static unsigned int tw686x_fields_map(v4l2_std_id std, unsigned int fps)
> >  		   8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 0, 0
> >  	};
> >  
> > -	unsigned int i =
> > -		(std & V4L2_STD_625_50) ? std_625_50[fps] : std_525_60[fps];
> > +	unsigned int i;
> > +
> > +	if (std & V4L2_STD_525_60) {
> > +		if (fps > ARRAY_SIZE(std_525_60))
> > +			fps = 30;
> > +		i = std_525_60[fps];
> > +	} else {
> > +		if (fps > ARRAY_SIZE(std_625_50))
> > +			fps = 25;
> > +		i = std_625_50[fps];
> > +	}
> >  
> >  	return map[i];
> >  }
> > 
> > 
> > --
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> >   
> 


-- 
Thanks,
Mauro