On Thu, Jun 17, 2021 at 12:46:43PM -0700, Kees Cook wrote:

On Thu, Jun 17, 2021 at 10:24:58AM +0300, Leon Romanovsky wrote:

quoted

On Wed, Jun 16, 2021 at 01:37:44PM -0700, Kees Cook wrote:

quoted

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

Use the ether_addr_copy() helper instead, as already done for smac.

Signed-off-by: Kees Cook <redacted>
---
 drivers/infiniband/hw/mlx4/qp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
index 2ae22bf50016..4a2ef7daaded 100644
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c

@@ -3144,7 +3144,7 @@ static int build_mlx_header(struct mlx4_ib_qp *qp, const struct ib_ud_wr *wr,
 		mlx->sched_prio = cpu_to_be16(pcp);
 
 		ether_addr_copy(sqp->ud_header.eth.smac_h, ah->av.eth.s_mac);
-		memcpy(sqp->ud_header.eth.dmac_h, ah->av.eth.mac, 6);
+		ether_addr_copy(sqp->ud_header.eth.dmac_h, ah->av.eth.mac);
 		memcpy(&ctrl->srcrb_flags16[0], ah->av.eth.mac, 2);
 		memcpy(&ctrl->imm, ah->av.eth.mac + 2, 4);

I don't understand the last three lines. We are copying 6 bytes to
ah->av.eth.mac and immediately after that overwriting them.

I'm not following (the memcpy() is replaced by ether_addr_copy()).

Forget it, it was me who mixed src with dst in the memcpy() signature.

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>