Re: [PATCH] media: v4l2-compat-ioctl32: fix missing length copy in put_v4l2_buffer32

[tiffany lin <tiffany.lin@mediatek.com>]

Hi Hans,

On Thu, 2016-01-14 at 08:53 +0100, Hans Verkuil wrote:
> Hi Tiffany,
> 
> Good catch! But looking through the compat code I noticed that in the
> single-planar DMABUF case the length field is also never copied. I think
> it would be much simpler if the length field is just always copied instead
> of in each multiplanar or singleplanar mmap/userptr/dmabuf case. It will
> simplify the code and prevent such mistakes in the future.
> 
> Can you make a v2 that makes that change?
> 
Sure, I had sent v2.

best regards,
Tiffany
> Thanks!
> 
> 	Hans
> 
> On 01/14/2016 08:37 AM, Tiffany Lin wrote:
> > In v4l2-compliance utility, test QUERYBUF required correct length
> > value to go through each planar to check planar's length in multi-planar
> > 
> > Signed-off-by: Tiffany Lin <tiffany.lin@mediatek.com>
> > ---
> >  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > index 327e83a..5ba932a 100644
> > --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > @@ -521,6 +521,9 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
> >  		if (num_planes == 0)
> >  			return 0;
> >  
> > +		if (put_user(kp->length, &up->length))
> > +			return -EFAULT;
> > +
> >  		uplane = (__force struct v4l2_plane __user *)kp->m.planes;
> >  		if (get_user(p, &up->m.planes))
> >  			return -EFAULT;
> > 
>