[PATCH 5.11 065/122] vfio/pci: Add missing range check in vfio_pci_mmap

Greg Kroah-Hartman
2021-04-19T13:14:26Z

From: Christian A. Ehrhardt <lk@c--e.de>

commit 909290786ea335366e21d7f1ed5812b90f2f0a92 upstream.

When mmaping an extra device region verify that the region index
derived from the mmap offset is valid.

Fixes: a15b1883fee1 ("vfio_pci: Allow mapping extra regions")
Cc: stable@vger.kernel.org
Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
Message-Id: <20210412214124.GA241759@lisa.in-ulm.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cornelia Huck <cohuck@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 | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1658,6 +1658,8 @@ static int vfio_pci_mmap(void *device_da

index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);

+ if (index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions)
+ return -EINVAL;
if (vma->vm_end < vma->vm_start)
return -EINVAL;
if ((vma->vm_flags & VM_SHARED) == 0)
@@ -1666,7 +1668,7 @@ static int vfio_pci_mmap(void *device_da
int regnum = index - VFIO_PCI_NUM_REGIONS;
struct vfio_pci_region *region = vdev->region + regnum;

- if (region && region->ops && region->ops->mmap &&
+ if (region->ops && region->ops->mmap &&
(region->flags & VFIO_REGION_INFO_FLAG_MMAP))
return region->ops->mmap(vdev, region, vma);
return -EINVAL;