On 10/5/18 12:02 PM, Christian Brauner wrote:

quoted

+
+		err = nlmsg_parse(nlh, sizeof(struct ifaddrmsg), tb, IFA_MAX,
+				  ifa_ipv4_policy, extack);
+		if (err < 0)
+			return err;
 
-			tgt_net = rtnl_get_net_ns_capable(skb->sk,
-							  fillargs.netnsid);
-			if (IS_ERR(tgt_net))
-				return PTR_ERR(tgt_net);
+		for (i = 0; i <= IFA_MAX; ++i) {
+			if (!tb[i])
+				continue;
+			if (i == IFA_TARGET_NETNSID) {

Nit: For the sake of readability there could be an additional newline between the 
"continue" and the next if () condition.

quoted

+				fillargs.netnsid = nla_get_s32(tb[i]);
+
+				tgt_net = rtnl_get_net_ns_capable(skb->sk,
+								  fillargs.netnsid);
+				if (IS_ERR(tgt_net)) {
+					NL_SET_ERR_MSG(extack, "Invalid target namespace id");

Nit: Hm, maybe "Invalid target network namespace id" would be better.
You never know what namespace comes along some time later. :)

done.