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

[David Ahern <dsahern@gmail.com>]

On 2/3/18 12:17 PM, Stephen Hemminger wrote:
> On Sat,  3 Feb 2018 14:29:04 +0100
> Christian Brauner <christian.brauner@ubuntu.com> 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?
> 

extack needs to be filled in too.