On Thu, 25 Feb 2016 13:34:43 +0200
"Michael S. Tsirkin" <mst@xxxxxxxxxx> 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;
>
> everywhere.
>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> drivers/vfio/pci/vfio_pci.c | 9 ++++++---
> drivers/vfio/platform/vfio_platform_common.c | 9 ++++++---
> drivers/vfio/vfio_iommu_type1.c | 6 ++++--
> 3 files changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 2760a7b..27a727a 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -446,7 +446,8 @@ 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;
Ok, but where do we return 0 on success now?
>
> } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
> struct pci_dev *pdev = vdev->pdev;
> @@ -520,7 +521,8 @@ static long vfio_pci_ioctl(void *device_data,
> return -EINVAL;
> }
>
> - return copy_to_user((void __user *)arg, &info, minsz);
> + if (copy_to_user((void __user *)arg, &info, minsz))
> + return -EFAULT;
>
> } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
> struct vfio_irq_info info;
> @@ -555,7 +557,8 @@ static long vfio_pci_ioctl(void *device_data,
> else
> info.flags |= VFIO_IRQ_INFO_NORESIZE;
>
> - return copy_to_user((void __user *)arg, &info, minsz);
> + if (copy_to_user((void __user *)arg, &info, minsz))
> + return -EFAULT;
>
> } else if (cmd == VFIO_DEVICE_SET_IRQS) {
> struct vfio_irq_set hdr;
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index 418cdd9..eea367f 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -219,7 +219,8 @@ static long vfio_platform_ioctl(void *device_data,
> info.num_regions = vdev->num_regions;
> info.num_irqs = vdev->num_irqs;
>
> - return copy_to_user((void __user *)arg, &info, minsz);
> + if (copy_to_user((void __user *)arg, &info, minsz))
> + return -EFAULT;
>
> } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
> struct vfio_region_info info;
> @@ -240,7 +241,8 @@ static long vfio_platform_ioctl(void *device_data,
> 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;
>
> } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
> struct vfio_irq_info info;
> @@ -259,7 +261,8 @@ static long vfio_platform_ioctl(void *device_data,
> info.flags = vdev->irqs[info.index].flags;
> info.count = vdev->irqs[info.index].count;
>
> - return copy_to_user((void __user *)arg, &info, minsz);
> + if (copy_to_user((void __user *)arg, &info, minsz))
> + return -EFAULT;
>
> } else if (cmd == VFIO_DEVICE_SET_IRQS) {
> struct vfio_irq_set hdr;
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 6f1ea3d..62614f7 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -999,7 +999,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>
> info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
>
> - return copy_to_user((void __user *)arg, &info, minsz);
> + if (copy_to_user((void __user *)arg, &info, minsz))
> + return -EFAULT;
>
> } else if (cmd == VFIO_IOMMU_MAP_DMA) {
> struct vfio_iommu_type1_dma_map map;
> @@ -1032,7 +1033,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
> if (ret)
> return ret;
>
> - return copy_to_user((void __user *)arg, &unmap, minsz);
> + if (copy_to_user((void __user *)arg, &unmap, minsz))
> + return -EFAULT;
> }
>
> return -ENOTTY;
All successes now land here in their respective files. Thanks,
Alex
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