Commit ec061546 authored by Xiao Liang's avatar Xiao Liang Committed by Jakub Kicinski
Browse files

rtnetlink: Lookup device in target netns when creating link 



When creating link, lookup for existing device in target net namespace
instead of current one.
For example, two links created by:

  # ip link add dummy1 type dummy
  # ip link add netns ns1 dummy1 type dummy

should have no conflict since they are in different namespaces.

Signed-off-by: default avatarXiao Liang <shaw.leon@gmail.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250219125039.18024-2-shaw.leon@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 4fe67dd2

net/core/rtnetlink.c

+8 −2
Original line number Diff line number Diff line
@@ -3867,20 +3867,26 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
{

	struct nlattr ** const tb = tbs->tb;

	struct net *net = sock_net(skb->sk);

	struct net *device_net;

	struct net_device *dev;

	struct ifinfomsg *ifm;

	bool link_specified;



	/* When creating, lookup for existing device in target net namespace */

	device_net = (nlh->nlmsg_flags & NLM_F_CREATE) &&

		     (nlh->nlmsg_flags & NLM_F_EXCL) ?

		     tgt_net : net;



	ifm = nlmsg_data(nlh);

	if (ifm->ifi_index > 0) {

		link_specified = true;

		dev = __dev_get_by_index(net, ifm->ifi_index);

		dev = __dev_get_by_index(device_net, ifm->ifi_index);

	} else if (ifm->ifi_index < 0) {

		NL_SET_ERR_MSG(extack, "ifindex can't be negative");

		return -EINVAL;

	} else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) {

		link_specified = true;

		dev = rtnl_dev_get(net, tb);

		dev = rtnl_dev_get(device_net, tb);

	} else {

		link_specified = false;

		dev = NULL;