[PATCH 4.4 16/74] vfio: fix ioctl error handling

Greg Kroah-Hartman
2016-03-08T00:24:34Z

From: Michael S. Tsirkin <mst@redhat.com>

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>

---
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(-)

--- 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_
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_
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_
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;
--- 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 *de
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 *de
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 *de
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;
--- 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

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
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;