rtnetlink: Fetch IFLA_LINK_NETNSID in rtnl_newlink().

Another netns option for RTM_NEWLINK is IFLA_LINK_NETNSID and
is fetched in rtnl_newlink_create().

This must be done before holding rtnl_net_lock().

Let's move IFLA_LINK_NETNSID processing to rtnl_newlink().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f6823c8d21ad017b957d5111bc6021b7719cf58f..eee0f820ddf6b1f9fac1d0bc0eb2d8f77f5ecc41 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3634,7 +3634,7 @@ static int rtnl_group_changelink(const struct sk_buff *skb,
 
 static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
                               const struct rtnl_link_ops *ops,
-                              struct net *tgt_net,
+                              struct net *tgt_net, struct net *link_net,
                               const struct nlmsghdr *nlh,
                               struct nlattr **tb, struct nlattr **data,
                               struct netlink_ext_ack *extack)
@@ -3644,7 +3644,6 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
        u32 portid = NETLINK_CB(skb).portid;
        struct net_device *dev;
        char ifname[IFNAMSIZ];
-       struct net *link_net;
        int err;
 
        if (!ops->alloc && !ops->setup)
@@ -3657,22 +3656,6 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
                name_assign_type = NET_NAME_ENUM;
        }
 
-       if (tb[IFLA_LINK_NETNSID]) {
-               int id = nla_get_s32(tb[IFLA_LINK_NETNSID]);
-
-               link_net = get_net_ns_by_id(tgt_net, id);
-               if (!link_net) {
-                       NL_SET_ERR_MSG(extack, "Unknown network namespace id");
-                       err =  -EINVAL;
-                       goto out;
-               }
-               err = -EPERM;
-               if (!netlink_ns_capable(skb, link_net->user_ns, CAP_NET_ADMIN))
-                       goto out;
-       } else {
-               link_net = NULL;
-       }
-
        dev = rtnl_create_link(link_net ? : tgt_net, ifname,
                               name_assign_type, ops, tb, extack);
        if (IS_ERR(dev)) {
@@ -3705,9 +3688,6 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
                        goto out_unregister;
        }
 out:
-       if (link_net)
-               put_net(link_net);
-
        return err;
 out_unregister:
        if (ops->newlink) {
@@ -3723,7 +3703,7 @@ out_unregister:
 
 static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                          const struct rtnl_link_ops *ops,
-                         struct net *tgt_net,
+                         struct net *tgt_net, struct net *link_net,
                          struct rtnl_newlink_tbs *tbs,
                          struct nlattr **data,
                          struct netlink_ext_ack *extack)
@@ -3772,16 +3752,16 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                return -EOPNOTSUPP;
        }
 
-       return rtnl_newlink_create(skb, ifm, ops, tgt_net, nlh, tb, data, extack);
+       return rtnl_newlink_create(skb, ifm, ops, tgt_net, link_net, nlh, tb, data, extack);
 }
 
 static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                        struct netlink_ext_ack *extack)
 {
        struct nlattr **tb, **linkinfo, **data = NULL;
+       struct net *tgt_net, *link_net = NULL;
        struct rtnl_link_ops *ops = NULL;
        struct rtnl_newlink_tbs *tbs;
-       struct net *tgt_net;
        int ops_srcu_index;
        int ret;
 
@@ -3852,8 +3832,27 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                goto put_ops;
        }
 
-       ret = __rtnl_newlink(skb, nlh, ops, tgt_net, tbs, data, extack);
+       if (tb[IFLA_LINK_NETNSID]) {
+               int id = nla_get_s32(tb[IFLA_LINK_NETNSID]);
+
+               link_net = get_net_ns_by_id(tgt_net, id);
+               if (!link_net) {
+                       NL_SET_ERR_MSG(extack, "Unknown network namespace id");
+                       ret =  -EINVAL;
+                       goto put_net;
+               }
+
+               if (!netlink_ns_capable(skb, link_net->user_ns, CAP_NET_ADMIN)) {
+                       ret = -EPERM;
+                       goto put_net;
+               }
+       }
+
+       ret = __rtnl_newlink(skb, nlh, ops, tgt_net, link_net, tbs, data, extack);
 
+put_net:
+       if (link_net)
+               put_net(link_net);
        put_net(tgt_net);
 put_ops:
        if (ops)