vfio: fix ioctl error handling

commit 8160c4e455820d5008a1116d2dca35f0363bb062 upstream.

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
	return copy_to_user(...)) ?
		-EFAULT : 0;

everywhere.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 56bf6dbb93db7ac281a0af4fa01a8d212fd87670..9982cb176ce86f2a7fd46fc9e205bf94c9403624 100644 (file)
--- 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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 418cdd9ba3f4841353c5cbdddb345e9363578736..e65b142d34222dd4ba548e46c44017d2b762cf06 100644 (file)
--- 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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 59d47cb638d5d18aac6700157ecc9be918772f91..ecb826eefe0214861bf5e141b34ca74ecf804598 100644 (file)
--- 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);
+               return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
 
        } 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);
+               return copy_to_user((void __user *)arg, &unmap, minsz) ?
+                       -EFAULT : 0;
        }
 
        return -ENOTTY;