On 12/06/2019 12:43, 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.
>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
> ---
> 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) {
>
--
Regards,
Vincenzo
