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Groups > linux.kernel > #1352414

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

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

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;

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[PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 09/74] parisc: Fix ptrace syscall number and return value modification Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 18/74] arm/arm64: KVM: Fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 10/74] mips/kvm: fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 12/74] fbcon: set a default value to blink interval Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 03/74] Btrfs: fix deadlock running delayed iputs at transaction commit time Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 07/74] block: Initialize max_dev_sectors to 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 16/74] vfio: fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  Re: [PATCH 4.4 00/74] 4.4.5-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-08 12:50 +0100
    Re: [PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 15:20 +0100
  Re: [PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 15:40 +0100
    Re: [PATCH 4.4 00/74] 4.4.5-stable review Kevin Hilman <khilman@baylibre.com> - 2016-03-09 06:40 +0100
  Re: [PATCH 4.4 00/74] 4.4.5-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-08 17:30 +0100
    Re: [PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-09 03:10 +0100

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