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

From: Christian Brauner <[email-masked]>
Date: Sun, 4 Feb 2018 13:12:08 +0100

On Sat, Feb 03, 2018 at 07:09:55PM -0700, David Ahern wrote:
> On 2/3/18 12:17 PM, Stephen Hemminger wrote:
> > 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?
> > 
> 
> extack needs to be filled in too.

Yeah, it should report that an invalid network namespace identifier has
been specified.

Thanks!
Christian