From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: Re: [PATCH v16 15/16] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Date: Fri, 7 Jun 2019 20:58:05 -0700 Message-ID: <201906072058.BB57EFA@keescook> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Andrey Konovalov Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Catalin Marinas , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander List-Id: linux-rdma@vger.kernel.org On Mon, Jun 03, 2019 at 06:55:17PM +0200, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > vaddr_get_pfn() uses provided user pointers for vma lookups, which can > only by done with untagged pointers. > > Untag user pointers in this function. > > Signed-off-by: Andrey Konovalov Reviewed-by: Kees Cook -Kees > --- > drivers/vfio/vfio_iommu_type1.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 3ddc375e7063..528e39a1c2dd 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, > > down_read(&mm->mmap_sem); > > + vaddr = untagged_addr(vaddr); > + > vma = find_vma_intersection(mm, vaddr, vaddr + 1); > > if (vma && vma->vm_flags & VM_PFNMAP) { > -- > 2.22.0.rc1.311.g5d7573a151-goog > -- Kees Cook