From: Michael S. Tsirkin <mst@redhat.com>
Date: Sun, 28 Feb 2016 14:31:39 +0000 (+0200)
Subject: vfio: fix ioctl error handling
X-Git-Tag: v4.5-rc7~29^2
X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=8160c4e455820d5008a1116d2dca35f0363bb062

vfio: fix ioctl error handling

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>
---

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 2760a7ba3f30..8c80a48e3233 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 418cdd9ba3f4..e65b142d3422 100644
--- 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 *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;
@@ -240,7 +241,8 @@ 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;
@@ -259,7 +261,8 @@ 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 6f1ea3dddbad..75b24e93cedb 100644
--- 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 *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;
@@ -1032,7 +1033,8 @@ 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;