From b61ad68a9fe85d29d5363eb36860164a049723cf Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Wed, 24 Jan 2018 15:26:34 +0100 Subject: [PATCH] rtnetlink: enable IFLA_IF_NETNSID for RTM_DELLINK - Backwards Compatibility: If userspace wants to determine whether RTM_DELLINK 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_DELLINK with a IFLA_IF_NETNSID property. If they receive EOPNOTSUPP then the kernel does not support the IFLA_IF_NETNSID property with RTM_DELLINK. 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 Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 39 ++++++++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 11 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index d0c02943c05a..f111557958bb 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2639,36 +2639,53 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { struct net *net = sock_net(skb->sk); - struct net_device *dev; + struct net *tgt_net = net; + struct net_device *dev = NULL; struct ifinfomsg *ifm; char ifname[IFNAMSIZ]; struct nlattr *tb[IFLA_MAX+1]; int err; + int netnsid = -1; err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy, extack); if (err < 0) return err; - if (tb[IFLA_IF_NETNSID]) - return -EOPNOTSUPP; - if (tb[IFLA_IFNAME]) nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ); + if (tb[IFLA_IF_NETNSID]) { + netnsid = nla_get_s32(tb[IFLA_IF_NETNSID]); + tgt_net = get_target_net(NETLINK_CB(skb).sk, netnsid); + if (IS_ERR(tgt_net)) + return PTR_ERR(tgt_net); + } + + err = -EINVAL; ifm = nlmsg_data(nlh); if (ifm->ifi_index > 0) - dev = __dev_get_by_index(net, ifm->ifi_index); + dev = __dev_get_by_index(tgt_net, ifm->ifi_index); else if (tb[IFLA_IFNAME]) - dev = __dev_get_by_name(net, ifname); + dev = __dev_get_by_name(tgt_net, ifname); else if (tb[IFLA_GROUP]) - return rtnl_group_dellink(net, nla_get_u32(tb[IFLA_GROUP])); + err = rtnl_group_dellink(tgt_net, nla_get_u32(tb[IFLA_GROUP])); else - return -EINVAL; + goto out; - if (!dev) - return -ENODEV; + if (!dev) { + if (tb[IFLA_IFNAME] || ifm->ifi_index > 0) + err = -ENODEV; - return rtnl_delete_link(dev); + goto out; + } + + err = rtnl_delete_link(dev); + +out: + if (netnsid >= 0) + put_net(tgt_net); + + return err; } int rtnl_configure_link(struct net_device *dev, const struct ifinfomsg *ifm) -- 2.30.2