Re: [PATCH] IB/mlx4: Avoid field-overflowing memcpy()
From: Leon Romanovsky <leon@kernel.org>
Date: 2021-06-17 07:25:05
Also in:
linux-hardening, lkml
On Wed, Jun 16, 2021 at 01:37:44PM -0700, Kees Cook wrote:
quoted hunk ↗ jump to hunk
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.
Jack,
Do you remember what you wanted to achieve in commit
6ee51a4e866b ("mlx4: Adjust QP1 multiplexing for RoCE/SRIOV")
Thanks
-- 2.25.1