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 2f8a0552d020aeff9d1df53d7c7a9d7bc574d5d0..bc7bc4e26c898c6c65e922ca2c6ef2b5971fe381 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -375,7 +375,8 @@ 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;
@@ -448,7 +449,8 @@ 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;
@@ -482,7 +484,8 @@ 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/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 4a9d666f1e9186ed07071c0d909ba167e814998a..3d1cbbd730bc71d10629d1b0b3a48a8542cd0fcd 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -928,7 +928,8 @@ 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;
@@ -961,7 +962,8 @@ 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;