[PATCH 55/64] RDMA/mlx5: Use struct_group() to zero struct mlx5_ib_mr

Kees Cook
2021-07-27T21:07:06Z

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Add struct_group() to mark region of struct mlx5_ib_mr that should be
initialized to zero.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/infiniband/hw/mlx5/mlx5_ib.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 585fb00bdce8..830066e95260 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -644,6 +644,7 @@ struct mlx5_ib_mr {
struct ib_umem *umem;

/* This is zero'd when the MR is allocated */
+ struct_group(cleared,
union {
/* Used only while the MR is in the cache */
struct {
@@ -691,12 +692,13 @@ struct mlx5_ib_mr {
bool is_odp_implicit;
};
};
+ );
};

/* 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(&mr->cleared, 0, sizeof(mr->cleared));
}

static inline bool is_odp_mr(struct mlx5_ib_mr *mr)
--
2.30.2