vfio: fix ioctl error handling

[ Upstream commit 8160c4e455820d5008a1116d2dca35f0363bb062 ]

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.

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index e9851ad..c0f4ab8 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 abcff7a..973b24f 100644 (file)
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -163,7 +163,8 @@ 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;
@@ -184,7 +185,8 @@ 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;
@@ -203,7 +205,8 @@ 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 57d8c37..0922165 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -986,7 +986,8 @@ 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;
@@ -1019,7 +1020,8 @@ 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;