From: Alex Williamson Date: Tue, 8 Jan 2019 05:13:22 +0000 (-0700) Subject: vfio/type1: Fix unmap overflow off-by-one X-Git-Tag: v4.19.16~25 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=719aee2c5ba17c0c87977dad59904b5af06821f0;p=users%2Fdwmw2%2Flinux.git vfio/type1: Fix unmap overflow off-by-one commit 58fec830fc19208354895d9832785505046d6c01 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index d9fd3188615dc..64cbc2d007c9e 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;