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;
