Re: [PATCH] V4L2: ov7670: fix a wrong index, potentially Oopsing the kernel from user-space

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

Hi Guennadi,

On Tuesday 13 May 2014 14:31:25 Guennadi Liakhovetski wrote:
> On Tue, 13 May 2014, Laurent Pinchart wrote:
> > On Monday 14 April 2014 15:49:34 Guennadi Liakhovetski wrote:
> > > Commit 75e2bdad8901a0b599e01a96229be922eef1e488 "ov7670: allow
> > > configuration of image size, clock speed, and I/O method" uses a wrong
> > > index to iterate an array. Apart from being wrong, it also uses an
> > > unchecked value from user-space, which can cause access to unmapped
> > > memory in the kernel, triggered by a normal desktop user with rights to
> > > use V4L2 devices.
> > > 
> > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > > ---
> > > 
> > > Jonathan,
> > > I'd prefer to first post it to the lists to maybe have someone test it
> > > ;)
> > > Otherwise - I've got a couple more fixes for 3.15, which I hope to make
> > > ready and push in a couple of weeks... So, with your ack I can take this
> > > one too, or, if you prefer to push it earlier - would be good too.
> > 
> > What's your plan for this patch ? Will you send a pull request ?
> > Alternatively I can take it in my tree.
> 
> https://patchwork.linuxtv.org/patch/23815/

Sorry for missing that. I'll mark https://patchwork.linuxtv.org/patch/23599/ 
as accepted then.

> > >  drivers/media/i2c/ov7670.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> > > index e8a1ce2..cdd7c1b 100644
> > > --- a/drivers/media/i2c/ov7670.c
> > > +++ b/drivers/media/i2c/ov7670.c
> > > @@ -1109,7 +1109,7 @@ static int ov7670_enum_framesizes(struct
> > > v4l2_subdev
> > > *sd, * windows that fall outside that.
> > > 
> > >  	 */
> > >  	
> > >  	for (i = 0; i < n_win_sizes; i++) {
> > > 
> > > -		struct ov7670_win_size *win = &info->devtype->win_sizes[index];
> > > +		struct ov7670_win_size *win = &info->devtype->win_sizes[i];
> > > 
> > >  		if (info->min_width && win->width < info->min_width)
> > >  		
> > >  			continue;
> > >  		
> > >  		if (info->min_height && win->height < info->min_height)

-- 
Regards,

Laurent Pinchart