Re: [PATCH v16 15/16] vfio/type1, arm64: untag user pointers in vaddr_get_pfn
From: Kees Cook <hidden>
Date: 2019-06-08 03:58:09
Also in:
amd-gfx, dri-devel, kvm, linux-kselftest, linux-media, linux-mm, linux-rdma, lkml
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 <redacted>
Reviewed-by: Kees Cook <redacted> -Kees
quoted hunk ↗ jump to hunk
--- 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
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