Re: [PATCH] IB/mlx4: Test port number before querying type.

[Leon Romanovsky <leon@kernel.org>]

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On Mon, Jul 02, 2018 at 02:02:34PM -0700, Tarick Bedeir wrote:
> rdma_ah_find_type() can reach into ib_device->port_immutable with a
> potentially out-of-bounds port number, so check that the port number is
> valid first.
>
> Fixes: 44c58487d51a ("IB/core: Define 'ib' and 'roce' rdma_ah_attr types")
> Signed-off-by: Tarick Bedeir <tarick@google.com>
> ---
>  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 f045491f2c14..4f1dabecf9a5 100644
> --- a/drivers/infiniband/hw/mlx4/qp.c
> +++ b/drivers/infiniband/hw/mlx4/qp.c
> @@ -4034,9 +4034,9 @@ static void to_rdma_ah_attr(struct mlx4_ib_dev *ibdev,
>  	u8 port_num = path->sched_queue & 0x40 ? 2 : 1;
>
>  	memset(ah_attr, 0, sizeof(*ah_attr));
> -	ah_attr->type = rdma_ah_find_type(&ibdev->ib_dev, port_num);
>  	if (port_num == 0 || port_num > dev->caps.num_ports)

Did you get any warning from any checker about out-of-bounds access?

According to the line above, port_num can be 2 or 1 which are valid ports for mlx4
and the check above doesn't do much.

>  		return;
> +	ah_attr->type = rdma_ah_find_type(&ibdev->ib_dev, port_num);
>
>  	if (ah_attr->type == RDMA_AH_ATTR_TYPE_ROCE)
>  		rdma_ah_set_sl(ah_attr, ((path->sched_queue >> 3) & 0x7) |
> --
> 2.18.0.399.gad0ab374a1-goog
>

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