rtnetlink: enable IFLA_IF_NETNSID for RTM_NEWLINK

- Backwards Compatibility:
  If userspace wants to determine whether RTM_NEWLINK supports the
  IFLA_IF_NETNSID property they should first send an RTM_GETLINK request
  with IFLA_IF_NETNSID on lo. If either EACCESS is returned or the reply
  does not include IFLA_IF_NETNSID userspace should assume that
  IFLA_IF_NETNSID is not supported on this kernel.
  If the reply does contain an IFLA_IF_NETNSID property userspace
  can send an RTM_NEWLINK with a IFLA_IF_NETNSID property. If they receive
  EOPNOTSUPP then the kernel does not support the IFLA_IF_NETNSID property
  with RTM_NEWLINK. Userpace should then fallback to other means.

- Security:
  Callers must have CAP_NET_ADMIN in the owning user namespace of the
  target network namespace.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Christian Brauner 2018-01-29 18:07:20 +01:00 committed by David S. Miller
parent 91e6dd8284
commit 5bb8ed0754

View File

@ -2952,14 +2952,10 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
name_assign_type = NET_NAME_ENUM;
}
dest_net = rtnl_link_get_net(net, tb);
dest_net = rtnl_link_get_net_capable(skb, net, tb, CAP_NET_ADMIN);
if (IS_ERR(dest_net))
return PTR_ERR(dest_net);
err = -EPERM;
if (!netlink_ns_capable(skb, dest_net->user_ns, CAP_NET_ADMIN))
goto out;
if (tb[IFLA_LINK_NETNSID]) {
int id = nla_get_s32(tb[IFLA_LINK_NETNSID]);