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SubjectRe: [PATCH] vfio: checking of validity of user vaddr in vfio_dma_rw
On Wed, Apr 08, 2020 at 03:11:21AM -0400, Yan Zhao wrote:
> instead of calling __copy_to/from_user(), use copy_to_from_user() to
> ensure vaddr range is a valid user address range before accessing them.
>
> Cc: Kees Cook <keescook@chromium.org>
>
> Fixes: 8d46c0cca5f4 ("vfio: introduce vfio_dma_rw to read/write a range of IOVAs")
> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>

Thanks!

Reported-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
> drivers/vfio/vfio_iommu_type1.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 3aefcc8e2933..fbc58284b333 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2345,10 +2345,10 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu,
> vaddr = dma->vaddr + offset;
>
> if (write)
> - *copied = __copy_to_user((void __user *)vaddr, data,
> + *copied = copy_to_user((void __user *)vaddr, data,
> count) ? 0 : count;
> else
> - *copied = __copy_from_user(data, (void __user *)vaddr,
> + *copied = copy_from_user(data, (void __user *)vaddr,
> count) ? 0 : count;
> if (kthread)
> unuse_mm(mm);
> --
> 2.17.1
>

--
Kees Cook

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