Re: [PATCH for-next] RDMA/hns: Fix memory corruption when allocating XRCDN

[Leon Romanovsky <leon@kernel.org>]

On Fri, Mar 19, 2021 at 04:45:36PM +0800, Weihang Li wrote:
> It's incorrect to cast the type of pointer to xrcdn from (u32 *) to
> (unsigned long *), then pass it into hns_roce_bitmap_alloc(), this will
> lead to a memory corruption.
> 
> Fixes: 32548870d438 ("RDMA/hns: Add support for XRC on HIP09")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Weihang Li <liweihang@huawei.com>
> ---
>  drivers/infiniband/hw/hns/hns_roce_pd.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/hns/hns_roce_pd.c b/drivers/infiniband/hw/hns/hns_roce_pd.c
> index 3ca51ce..16d6b69 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_pd.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_pd.c
> @@ -140,8 +140,14 @@ void hns_roce_cleanup_uar_table(struct hns_roce_dev *hr_dev)
>  
>  static int hns_roce_xrcd_alloc(struct hns_roce_dev *hr_dev, u32 *xrcdn)
>  {
> -	return hns_roce_bitmap_alloc(&hr_dev->xrcd_bitmap,
> -				     (unsigned long *)xrcdn);
> +	unsigned long obj;
> +	int ret;
> +
> +	ret = hns_roce_bitmap_alloc(&hr_dev->xrcd_bitmap, &obj);
> +
> +	*xrcdn = (u32)obj;

NIT, it will be safer if you don't set set xrcdn after hns_roce_bitmap_alloc() failed.

Thanks

> +
> +	return ret;
>  }
>  
>  static void hns_roce_xrcd_free(struct hns_roce_dev *hr_dev,
> -- 
> 2.8.1
>