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Groups > linux.kernel > #1343125 > unrolled thread

[PATCH for-4.5] vfio: fix ioctl error handling

Started by"Michael S. Tsirkin" <mst@redhat.com>
First post2016-02-25 12:40 +0100
Last post2016-02-28 15:20 +0100
Articles 4 — 3 participants

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  [PATCH for-4.5] vfio: fix ioctl error handling "Michael S. Tsirkin" <mst@redhat.com> - 2016-02-25 12:40 +0100
    Re: [PATCH for-4.5] vfio: fix ioctl error handling Dan Carpenter <dan.carpenter@oracle.com> - 2016-02-26 14:50 +0100
    Re: [PATCH for-4.5] vfio: fix ioctl error handling Alex Williamson <alex.williamson@redhat.com> - 2016-02-28 14:30 +0100
      Re: [PATCH for-4.5] vfio: fix ioctl error handling "Michael S. Tsirkin" <mst@redhat.com> - 2016-02-28 15:20 +0100

#1343125 — [PATCH for-4.5] vfio: fix ioctl error handling

From"Michael S. Tsirkin" <mst@redhat.com>
Date2016-02-25 12:40 +0100
Subject[PATCH for-4.5] vfio: fix ioctl error handling
Message-ID<r62qZ-37z-11@gated-at.bofh.it>
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
	if (copy_to_user(...))
		return -EFAULT;

everywhere.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.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 2760a7b..27a727a 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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 418cdd9..eea367f 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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 6f1ea3d..62614f7 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);
+		if (copy_to_user((void __user *)arg, &info, minsz))
+			return -EFAULT;
 
 	} 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);
+		if (copy_to_user((void __user *)arg, &unmap, minsz))
+			return -EFAULT;
 	}
 
 	return -ENOTTY;
-- 
MST

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#1344253

FromDan Carpenter <dan.carpenter@oracle.com>
Date2016-02-26 14:50 +0100
Message-ID<r6qWm-3Zw-9@gated-at.bofh.it>
In reply to#1343125
On Thu, Feb 25, 2016 at 01:34:43PM +0200, Michael S. Tsirkin wrote:
> 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
> 	if (copy_to_user(...))
> 		return -EFAULT;
> 
> everywhere.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

Heh.  I don't exactly deserve this credit.

I have updated Smatch to check for this (will push next week probably).
I wouldn't have caught the issues in vfio_platform_common.c because
that's ARM only.

regards,
dan carpenter

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#1345250

FromAlex Williamson <alex.williamson@redhat.com>
Date2016-02-28 14:30 +0100
Message-ID<r79A6-2SF-19@gated-at.bofh.it>
In reply to#1343125
On Thu, 25 Feb 2016 13:34:43 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> 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
> 	if (copy_to_user(...))
> 		return -EFAULT;
> 
> everywhere.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.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 2760a7b..27a727a 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;

Ok, but where do we return 0 on success now?

>  
>  	} 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
>  
>  	} 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
>  
>  	} 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 418cdd9..eea367f 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
>  
>  	} 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
>  
>  	} 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
>  
>  	} 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 6f1ea3d..62614f7 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);
> +		if (copy_to_user((void __user *)arg, &info, minsz))
> +			return -EFAULT;
>  
>  	} 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);
> +		if (copy_to_user((void __user *)arg, &unmap, minsz))
> +			return -EFAULT;
>  	}
>  
>  	return -ENOTTY;

All successes now land here in their respective files.  Thanks,

Alex

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#1345279

From"Michael S. Tsirkin" <mst@redhat.com>
Date2016-02-28 15:20 +0100
Message-ID<r7amu-3B3-17@gated-at.bofh.it>
In reply to#1345250
On Sun, Feb 28, 2016 at 07:23:22AM -0600, Alex Williamson wrote:
> On Thu, 25 Feb 2016 13:34:43 +0200
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > 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
> > 	if (copy_to_user(...))
> > 		return -EFAULT;
> > 
> > everywhere.
> > 
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.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 2760a7b..27a727a 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);
> > +		if (copy_to_user((void __user *)arg, &info, minsz))
> > +			return -EFAULT;
> 
> Ok, but where do we return 0 on success now?

Ouch. Thanks for pointing this out. Fixed in v2.

-- 
MST

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