Subject: Re: [PATCH net 1/1 v1] rtnetlink: require unique netns identifier

From: Stephen Hemminger <[email-masked]>
Date: Sat, 3 Feb 2018 11:17:01 -0800

On Sat,  3 Feb 2018 14:29:04 +0100
Christian Brauner <[email-masked]> wrote:

> +static int rtnl_ensure_unique_netns_attr(const struct sock *sk,
> +					 struct nlattr *tb[],
> +					 struct netlink_ext_ack *extack)
> +{
> +	int ret = -EINVAL;
> +	struct net *net = NULL, *unique_net = NULL;
> +
> +	/* Requests without network namespace ids have been able to specify
> +	 * multiple properties referring to different network namespaces so
> +	 * don't regress them.
> +	 */
> +	if (!tb[IFLA_IF_NETNSID])
> +		return 0;
> +
> +	if (!tb[IFLA_NET_NS_PID] && !tb[IFLA_NET_NS_FD])
> +		return 0;

Isn't this an error?

> +
> +	unique_net = get_net_ns_by_id(sock_net(sk), nla_get_s32(tb[IFLA_IF_NETNSID]));
> +	if (!unique_net)
> +		return -1;

Other paths are returning errno, so why -1 here?