From: Alex Williamson Date: Tue, 8 Jan 2019 05:13:22 +0000 (-0700) Subject: vfio/type1: Fix unmap overflow off-by-one X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=58fec830fc19208354895d9832785505046d6c01;p=linux.git vfio/type1: Fix unmap overflow off-by-one 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: stable@vger.kernel.org # v4.15+ Reported-by: Pei Zhang Debugged-by: Peter Xu Reviewed-by: Dan Carpenter Reviewed-by: Peter Xu Tested-by: Peter Xu Reviewed-by: Cornelia Huck Signed-off-by: Alex Williamson --- diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 7651cfb14836a..73652e21efec6 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;