[PATCH AUTOSEL 6.14 352/642] rtnetlink: Lookup device in target netns when creating link
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REVIEWED: 1 (0M)
From: Sasha Levin <sashal@kernel.org>
Date: 2025-05-05 22:28:24
Also in:
lkml, stable
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
1 review trailer.
From: Xiao Liang <redacted> [ Upstream commit ec061546c6cffbb8929495bba3953f0cc5e177fa ] 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 <redacted> Reviewed-by: Kuniyuki Iwashima <redacted> Link: https://patch.msgid.link/20250219125039.18024-2-shaw.leon@gmail.com (local) Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/core/rtnetlink.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 80e006940f51a..ab7041150f295 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -3865,20 +3865,26 @@ 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;
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2.39.5