[PATCH 4.2.y-ckt 28/98] vfio: fix ioctl error handling

Kamal Mostafa
2016-03-15T23:32:23Z

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: Kamal Mostafa <kamal@canonical.com>
---
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 964ad57..c2337f8 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);
+ 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 8c216de..dec1790 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -208,7 +208,8 @@ 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;
@@ -229,7 +230,8 @@ 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;
@@ -248,7 +250,8 @@ 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
--- 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;
--
2.7.0