On Thu, Nov 18, 2021 at 12:31:38PM -0800, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memset(), avoid intentionally writing across
> neighboring fields.
>
> Use memset_after() to zero the end of struct mlx5_ib_mr that should
> be initialized.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> drivers/infiniband/hw/mlx5/mlx5_ib.h | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
> index e636e954f6bf..af94c9fe8753 100644
> --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
> +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
> @@ -665,8 +665,7 @@ struct mlx5_ib_mr {
> /* User MR data */
> struct mlx5_cache_ent *cache_ent;
> struct ib_umem *umem;
> -
> - /* This is zero'd when the MR is allocated */
> + /* Everything after umem is zero'd when the MR is allocated */
> union {
> /* Used only while the MR is in the cache */
> struct {
> @@ -718,7 +717,7 @@ struct mlx5_ib_mr {
> /* Zero the fields in the mr that are variant depending on usage */
> static inline void mlx5_clear_mr(struct mlx5_ib_mr *mr)
> {
> - memset(mr->out, 0, sizeof(*mr) - offsetof(struct mlx5_ib_mr, out));
> + memset_after(mr, 0, umem);
I think that it is not equivalent change and you need "memset_after(mr, 0, cache_ent);"
to clear umem pointer too.
> }
>
> static inline bool is_odp_mr(struct mlx5_ib_mr *mr)
> --
> 2.30.2
>
