On Sun, 28 Feb 2016 16:25:07 +0200 "Michael S. Tsirkin" <[email protected]> wrote:
> On Sun, Feb 28, 2016 at 08:23:36AM -0600, Alex Williamson wrote: > > On Sun, 28 Feb 2016 15:51:49 +0200 > > "Michael S. Tsirkin" <[email protected]> wrote: > > > > > Calling return copy_to_user(...) in an ioctl will not > > > do the right thing if there's a pagefault: > > > copy_to_user returns the number of bytes not copied > > > in this case. > > > > > > Fix up vfio to do > > > if (copy_to_user(...)) > > > return -EFAULT; > > > return 0; > > > > > > everywhere. > > > > > > Cc: [email protected] > > > Signed-off-by: Michael S. Tsirkin <[email protected]> > > > --- > > > > > > Changes from v1: > > > fix up good path logic to return 0. > > > > > > Compiled only. > > > > > > drivers/vfio/pci/vfio_pci.c | 12 +++++++++--- > > > drivers/vfio/platform/vfio_platform_common.c | 12 +++++++++--- > > > drivers/vfio/vfio_iommu_type1.c | 8 ++++++-- > > > 3 files changed, 24 insertions(+), 8 deletions(-) > > > > > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > > > index 2760a7b..286b91f 100644 > > > --- a/drivers/vfio/pci/vfio_pci.c > > > +++ b/drivers/vfio/pci/vfio_pci.c > > > @@ -446,7 +446,9 @@ static long vfio_pci_ioctl(void *device_data, > > > info.num_regions = VFIO_PCI_NUM_REGIONS; > > > info.num_irqs = VFIO_PCI_NUM_IRQS; > > > > > > - return copy_to_user((void __user *)arg, &info, minsz); > > > + if (copy_to_user((void __user *)arg, &info, minsz)) > > > + return -EFAULT; > > > + return 0; > > > > Any objection to a ternary in each case? > > > > return copy_to_user((void __user *)arg, > > &info, minsz) ? -EFAULT : 0; > > If you prefer, I'll do it in v3. Looks clean and compact to me. Thanks, Alex
