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Subject: Re: [PATCH v2] nbd_genl_status: null check for nla_nest_start
To:     Navid Emamdoost <navid.emamdoost@gmail.com>, josef@toxicpanda.com
Cc:     kjlu@umn.edu, smccaman@umn.edu, secalert@redhat.com,
        emamd001@umn.edu, Jens Axboe <axboe@kernel.dk>,
        linux-block@vger.kernel.org, nbd@other.debian.org,
        linux-kernel@vger.kernel.org
References: <20190729130912.7imtg3hfnvb4lt2y@MacBook-Pro-91.local>
 <20190729164226.22632-1-navid.emamdoost@gmail.com>
From:   Bob Liu <bob.liu@oracle.com>
Message-ID: <1bcb2fc7-f64b-282c-36ab-eda9ccb4601d@oracle.com>
Date:   Tue, 30 Jul 2019 14:05:59 +0800
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On 7/30/19 12:42 AM, Navid Emamdoost wrote:
> nla_nest_start may fail and return NULL. The check is inserted, and
> errno is selected based on other call sites within the same source code.
> Update: removed extra new line.
> 
> Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
> ---
>  drivers/block/nbd.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 9bcde2325893..2410812d1e82 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -2149,6 +2149,11 @@ static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
>  	}
>  
>  	dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
> +	if (!dev_list) {
> +		ret = -EMSGSIZE;
> +		goto out;
> +	}
> +
>  	if (index == -1) {
>  		ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
>  		if (ret) {
> 

Looks good to me.
Reviewed-by: Bob Liu <bob.liu@oracle.com>