[v2,for-4.5] vfio: fix ioctl error handling

Message ID	1456667344-27786-1-git-send-email-mst@redhat.com (mailing list archive)
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Headers	show Return-Path: <kvm-owner@kernel.org> Date: Sun, 28 Feb 2016 15:51:49 +0200 From: "Michael S. Tsirkin" <mst@redhat.com> To: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, Alex Williamson <alex.williamson@redhat.com>, Baptiste Reynal <b.reynal@virtualopensystems.com>, Antonios Motakis <a.motakis@virtualopensystems.com>, Eric Auger <eric.auger@linaro.org>, Julia Lawall <Julia.Lawall@lip6.fr>, kvm@vger.kernel.org Subject: [PATCH v2 for-4.5] vfio: fix ioctl error handling Message-ID: <1456667344-27786-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: kvm-owner@vger.kernel.org Precedence: bulk

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1456667344-27786-1-git-send-email-mst@redhat.com (mailing list archive)

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Headers

Date: Sun, 28 Feb 2016 15:51:49 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org, Alex Williamson <alex.williamson@redhat.com>,
	Baptiste Reynal <b.reynal@virtualopensystems.com>,
	Antonios Motakis <a.motakis@virtualopensystems.com>,
	Eric Auger <eric.auger@linaro.org>,
	Julia Lawall <Julia.Lawall@lip6.fr>, kvm@vger.kernel.org
Subject: [PATCH v2 for-4.5] vfio: fix ioctl error handling
Message-ID: <1456667344-27786-1-git-send-email-mst@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Sender: kvm-owner@vger.kernel.org
Precedence: bulk

Commit Message

Michael S. Tsirkin Feb. 28, 2016, 1:51 p.m. UTC

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;
	return 0;

everywhere.

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Changes from v1:
	fix up good path logic to return 0.

Compiled only.

 drivers/vfio/pci/vfio_pci.c                  | 12 +++++++++---
 drivers/vfio/platform/vfio_platform_common.c | 12 +++++++++---
 drivers/vfio/vfio_iommu_type1.c              |  8 ++++++--
 3 files changed, 24 insertions(+), 8 deletions(-)

Comments

Alex Williamson Feb. 28, 2016, 2:23 p.m. UTC | #1

On Sun, 28 Feb 2016 15:51:49 +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;
> 	return 0;
> 
> everywhere.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 
> Changes from v1:
> 	fix up good path logic to return 0.
> 
> Compiled only.
> 
>  drivers/vfio/pci/vfio_pci.c                  | 12 +++++++++---
>  drivers/vfio/platform/vfio_platform_common.c | 12 +++++++++---
>  drivers/vfio/vfio_iommu_type1.c              |  8 ++++++--
>  3 files changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 2760a7b..286b91f 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -446,7 +446,9 @@ 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;
> +		return 0;

Any objection to a ternary in each case?

		return copy_to_user((void __user *)arg,
				    &info, minsz) ? -EFAULT : 0;
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Michael S. Tsirkin Feb. 28, 2016, 2:25 p.m. UTC | #2

On Sun, Feb 28, 2016 at 08:23:36AM -0600, Alex Williamson wrote:
> On Sun, 28 Feb 2016 15:51:49 +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;
> > 	return 0;
> > 
> > everywhere.
> > 
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > 
> > Changes from v1:
> > 	fix up good path logic to return 0.
> > 
> > Compiled only.
> > 
> >  drivers/vfio/pci/vfio_pci.c                  | 12 +++++++++---
> >  drivers/vfio/platform/vfio_platform_common.c | 12 +++++++++---
> >  drivers/vfio/vfio_iommu_type1.c              |  8 ++++++--
> >  3 files changed, 24 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> > index 2760a7b..286b91f 100644
> > --- a/drivers/vfio/pci/vfio_pci.c
> > +++ b/drivers/vfio/pci/vfio_pci.c
> > @@ -446,7 +446,9 @@ 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;
> > +		return 0;
> 
> Any objection to a ternary in each case?
> 
> 		return copy_to_user((void __user *)arg,
> 				    &info, minsz) ? -EFAULT : 0;

If you prefer, I'll do it in v3.

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Alex Williamson Feb. 28, 2016, 2:33 p.m. UTC | #3

On Sun, 28 Feb 2016 16:25:07 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Sun, Feb 28, 2016 at 08:23:36AM -0600, Alex Williamson wrote:
> > On Sun, 28 Feb 2016 15:51:49 +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;
> > > 	return 0;
> > > 
> > > everywhere.
> > > 
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > ---
> > > 
> > > Changes from v1:
> > > 	fix up good path logic to return 0.
> > > 
> > > Compiled only.
> > > 
> > >  drivers/vfio/pci/vfio_pci.c                  | 12 +++++++++---
> > >  drivers/vfio/platform/vfio_platform_common.c | 12 +++++++++---
> > >  drivers/vfio/vfio_iommu_type1.c              |  8 ++++++--
> > >  3 files changed, 24 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> > > index 2760a7b..286b91f 100644
> > > --- a/drivers/vfio/pci/vfio_pci.c
> > > +++ b/drivers/vfio/pci/vfio_pci.c
> > > @@ -446,7 +446,9 @@ 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;
> > > +		return 0;  
> > 
> > Any objection to a ternary in each case?
> > 
> > 		return copy_to_user((void __user *)arg,
> > 				    &info, minsz) ? -EFAULT : 0;  
> 
> If you prefer, I'll do it in v3.

Looks clean and compact to me.  Thanks,

Alex
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Michael S. Tsirkin Feb. 28, 2016, 2:55 p.m. UTC | #4

On Sun, Feb 28, 2016 at 08:33:50AM -0600, Alex Williamson wrote:
> On Sun, 28 Feb 2016 16:25:07 +0200
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Sun, Feb 28, 2016 at 08:23:36AM -0600, Alex Williamson wrote:
> > > On Sun, 28 Feb 2016 15:51:49 +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;
> > > > 	return 0;
> > > > 
> > > > everywhere.
> > > > 
> > > > Cc: stable@vger.kernel.org
> > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > > ---
> > > > 
> > > > Changes from v1:
> > > > 	fix up good path logic to return 0.
> > > > 
> > > > Compiled only.
> > > > 
> > > >  drivers/vfio/pci/vfio_pci.c                  | 12 +++++++++---
> > > >  drivers/vfio/platform/vfio_platform_common.c | 12 +++++++++---
> > > >  drivers/vfio/vfio_iommu_type1.c              |  8 ++++++--
> > > >  3 files changed, 24 insertions(+), 8 deletions(-)
> > > > 
> > > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> > > > index 2760a7b..286b91f 100644
> > > > --- a/drivers/vfio/pci/vfio_pci.c
> > > > +++ b/drivers/vfio/pci/vfio_pci.c
> > > > @@ -446,7 +446,9 @@ 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;
> > > > +		return 0;  
> > > 
> > > Any objection to a ternary in each case?
> > > 
> > > 		return copy_to_user((void __user *)arg,
> > > 				    &info, minsz) ? -EFAULT : 0;  
> > 
> > If you prefer, I'll do it in v3.
> 
> Looks clean and compact to me.  Thanks,
> 
> Alex

Does v3 I posted address your comment?

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 2760a7b..286b91f 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -446,7 +446,9 @@  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;
+		return 0;
 
 	} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
 		struct pci_dev *pdev = vdev->pdev;
@@ -520,7 +522,9 @@  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;
+		return 0;
 
 	} else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
 		struct vfio_irq_info info;
@@ -555,7 +559,9 @@  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;
+		return 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 418cdd9..0fc6b75 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -219,7 +219,9 @@  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;
+		return 0;
 
 	} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
 		struct vfio_region_info info;
@@ -240,7 +242,9 @@  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;
+		return 0;
 
 	} else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
 		struct vfio_irq_info info;
@@ -259,7 +263,9 @@  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;
+		return 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 6f1ea3d..557dfc6 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -999,7 +999,9 @@  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;
+		return 0;
 
 	} else if (cmd == VFIO_IOMMU_MAP_DMA) {
 		struct vfio_iommu_type1_dma_map map;
@@ -1032,7 +1034,9 @@  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 0;
 	}
 
 	return -ENOTTY;

[v2,for-4.5] vfio: fix ioctl error handling

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