From: Leon Romanovsky <leon@kernel.org>
To: Kees Cook <keescook@chromium.org>, Jack Morgenstein <jackm@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>, Yishai Hadas <yishaih@nvidia.com>,
Doug Ledford <dledford@redhat.com>,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] IB/mlx4: Avoid field-overflowing memcpy()
Date: Thu, 17 Jun 2021 10:24:58 +0300 [thread overview]
Message-ID: <YMr4ypsh7D3q1R5+@unreal> (raw)
In-Reply-To: <20210616203744.1248551-1-keescook@chromium.org>
On Wed, Jun 16, 2021 at 01:37:44PM -0700, Kees Cook wrote:
> 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 <keescook@chromium.org>
> ---
> 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
>
next prev parent reply other threads:[~2021-06-17 7:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-16 20:37 [PATCH] IB/mlx4: Avoid field-overflowing memcpy() Kees Cook
2021-06-17 7:24 ` Leon Romanovsky [this message]
2021-06-17 19:46 ` Kees Cook
2021-06-21 8:11 ` Leon Romanovsky
2021-06-22 0:05 ` Jason Gunthorpe
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