Messages in this thread | | | Date | Wed, 9 Jan 2019 11:11:03 +0800 | From | Peter Xu <> | Subject | Re: [PATCH] vfio/type1: Fix unmap overflow off-by-one |
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On Tue, Jan 08, 2019 at 09:40:06AM -0700, Alex Williamson wrote: > The below referenced commit adds a test for integer overflow, but in > doing so prevents the unmap ioctl from ever including the last page of > the address space. Subtract one to compare to the last address of the > unmap to avoid the overflow and wrap-around. > > Fixes: 71a7d3d78e3c ("vfio/type1: silence integer overflow warning") > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1662291 > Cc: Dan Carpenter <dan.carpenter@oracle.com> > Reported-by: Pei Zhang <pezhang@redhat.com> > Debugged-by: Peter Xu <peterx@redhat.com> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
I tested this against the QEMU reboot error and it works.
Reviewed-by: Peter Xu <peterx@redhat.com> Tested-by: Peter Xu <peterx@redhat.com>
Thanks,
> --- > drivers/vfio/vfio_iommu_type1.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 7651cfb14836..73652e21efec 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -878,7 +878,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > return -EINVAL; > if (!unmap->size || unmap->size & mask) > return -EINVAL; > - if (unmap->iova + unmap->size < unmap->iova || > + if (unmap->iova + unmap->size - 1 < unmap->iova || > unmap->size > SIZE_MAX) > return -EINVAL; > >
-- Peter Xu
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