diff mbox series

[net-next,v3,3/6] rtnetlink: Lookup device in target netns when creating link

Message ID 20241113125715.150201-4-shaw.leon@gmail.com (mailing list archive)
State Not Applicable
Delegated to: Johannes Berg
Headers show
Series net: Improve netns handling in RTNL and ip_tunnel | expand

Commit Message

Xiao Liang Nov. 13, 2024, 12:57 p.m. UTC 
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: Xiao Liang <shaw.leon@gmail.com>
---
 net/core/rtnetlink.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 327fa4957929..f573ace60234 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3846,20 +3846,26 @@  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;