Re: [PATCH 1/2] vfio/fsl-mc: return -EFAULT if copy_to_user() fails

[Diana Craciun OSS]

On 11/2/2020 11:45 PM, Alex Williamson wrote:
> Thanks, Dan.
>
> Diana, can I get an ack for this?  Thanks,


Yes, sure, I apologize for not doing it earlier.

Thanks,
Diana

> Alex
>
> On Fri, 23 Oct 2020 14:34:50 +0300
> Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> > The copy_to_user() function returns the number of bytes remaining to be
> > copied, but this code should return -EFAULT.
> >
> > Fixes: df747bcd5b21 ("vfio/fsl-mc: Implement VFIO_DEVICE_GET_REGION_INFO ioctl call")
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> >   drivers/vfio/fsl-mc/vfio_fsl_mc.c | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> > index 0113a980f974..21f22e3da11f 100644
> > --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> > +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> > @@ -248,7 +248,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
> >   		info.size = vdev->regions[info.index].size;
> >   		info.flags = vdev->regions[info.index].flags;
> >   
> > -		return copy_to_user((void __user *)arg, &info, minsz);
> > +		if (copy_to_user((void __user *)arg, &info, minsz))
> > +			return -EFAULT;
> > +		return 0;
> >   	}
> >   	case VFIO_DEVICE_GET_IRQ_INFO:
> >   	{
> > @@ -267,7 +269,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
> >   		info.flags = VFIO_IRQ_INFO_EVENTFD;
> >   		info.count = 1;
> >   
> > -		return copy_to_user((void __user *)arg, &info, minsz);
> > +		if (copy_to_user((void __user *)arg, &info, minsz))
> > +			return -EFAULT;
> > +		return 0;
> >   	}
> >   	case VFIO_DEVICE_SET_IRQS:
> >   	{