1 files changed, 85 insertions, 18 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index de24d394c69e..8a8c51937edf 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -921,7 +921,8 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
                + nla_total_size(4)  /* IFLA_EVENT */
                + nla_total_size(4)  /* IFLA_NEW_NETNSID */
                + nla_total_size(1); /* IFLA_PROTO_DOWN */
-
+               + nla_total_size(4)  /* IFLA_IF_NETNSID */
+               + 0;
 }
 
 static int rtnl_vf_ports_fill(struct sk_buff *skb, struct net_device *dev)
@@ -1370,13 +1371,14 @@ static noinline_for_stack int nla_put_ifalias(struct sk_buff *skb,
 }
 
 static int rtnl_fill_link_netnsid(struct sk_buff *skb,
-                                  const struct net_device *dev)
+                                  const struct net_device *dev,
+                                  struct net *src_net)
 {
         if (dev->rtnl_link_ops && dev->rtnl_link_ops->get_link_net) {
                 struct net *link_net = dev->rtnl_link_ops->get_link_net(dev);
 
                 if (!net_eq(dev_net(dev), link_net)) {
-                        int id = peernet2id_alloc(dev_net(dev), link_net);
+                        int id = peernet2id_alloc(src_net, link_net);
 
                         if (nla_put_s32(skb, IFLA_LINK_NETNSID, id))
                                 return -EMSGSIZE;
@@ -1427,10 +1429,11 @@ static int rtnl_fill_link_af(struct sk_buff *skb,
         return 0;
 }
 
-static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
+static int rtnl_fill_ifinfo(struct sk_buff *skb,
+                            struct net_device *dev, struct net *src_net,
                             int type, u32 pid, u32 seq, u32 change,
                             unsigned int flags, u32 ext_filter_mask,
-                            u32 event, int *new_nsid)
+                            u32 event, int *new_nsid, int tgt_netnsid)
 {
         struct ifinfomsg *ifm;
         struct nlmsghdr *nlh;
@@ -1448,6 +1451,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
         ifm->ifi_flags = dev_get_flags(dev);
         ifm->ifi_change = change;
 
+        if (tgt_netnsid >= 0 && nla_put_s32(skb, IFLA_IF_NETNSID, tgt_netnsid))
+                goto nla_put_failure;
+
         if (nla_put_string(skb, IFLA_IFNAME, dev->name) ||
             nla_put_u32(skb, IFLA_TXQLEN, dev->tx_queue_len) ||
             nla_put_u8(skb, IFLA_OPERSTATE,
@@ -1513,7 +1519,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
                         goto nla_put_failure;
         }
 
-        if (rtnl_fill_link_netnsid(skb, dev))
+        if (rtnl_fill_link_netnsid(skb, dev, src_net))
                 goto nla_put_failure;
 
         if (new_nsid &&
@@ -1571,6 +1577,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
         [IFLA_XDP]              = { .type = NLA_NESTED },
         [IFLA_EVENT]            = { .type = NLA_U32 },
         [IFLA_GROUP]            = { .type = NLA_U32 },
+        [IFLA_IF_NETNSID]       = { .type = NLA_S32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -1674,9 +1681,28 @@ static bool link_dump_filtered(struct net_device *dev,
         return false;
 }
 
+static struct net *get_target_net(struct sk_buff *skb, int netnsid)
+{
+        struct net *net;
+
+        net = get_net_ns_by_id(sock_net(skb->sk), netnsid);
+        if (!net)
+                return ERR_PTR(-EINVAL);
+
+        /* For now, the caller is required to have CAP_NET_ADMIN in
+         * the user namespace owning the target net ns.
+         */
+        if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) {
+                put_net(net);
+                return ERR_PTR(-EACCES);
+        }
+        return net;
+}
+
 static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 {
         struct net *net = sock_net(skb->sk);
+        struct net *tgt_net = net;
         int h, s_h;
         int idx = 0, s_idx;
         struct net_device *dev;
@@ -1686,6 +1712,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
         const struct rtnl_link_ops *kind_ops = NULL;
         unsigned int flags = NLM_F_MULTI;
         int master_idx = 0;
+        int netnsid = -1;
         int err;
         int hdrlen;
 
@@ -1704,6 +1731,15 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 
         if (nlmsg_parse(cb->nlh, hdrlen, tb, IFLA_MAX,
                         ifla_policy, NULL) >= 0) {
+                if (tb[IFLA_IF_NETNSID]) {
+                        netnsid = nla_get_s32(tb[IFLA_IF_NETNSID]);
+                        tgt_net = get_target_net(skb, netnsid);
+                        if (IS_ERR(tgt_net)) {
+                                tgt_net = net;
+                                netnsid = -1;
+                        }
+                }
+
                 if (tb[IFLA_EXT_MASK])
                         ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
 
@@ -1719,17 +1755,19 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 
         for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
                 idx = 0;
-                head = &net->dev_index_head[h];
+                head = &tgt_net->dev_index_head[h];
                 hlist_for_each_entry(dev, head, index_hlist) {
                         if (link_dump_filtered(dev, master_idx, kind_ops))
                                 goto cont;
                         if (idx < s_idx)
                                 goto cont;
-                        err = rtnl_fill_ifinfo(skb, dev, RTM_NEWLINK,
+                        err = rtnl_fill_ifinfo(skb, dev, net,
+                                               RTM_NEWLINK,
                                                NETLINK_CB(cb->skb).portid,
                                                cb->nlh->nlmsg_seq, 0,
                                                flags,
-                                               ext_filter_mask, 0, NULL);
+                                               ext_filter_mask, 0, NULL,
+                                               netnsid);
 
                         if (err < 0) {
                                 if (likely(skb->len))
@@ -1748,6 +1786,8 @@ out_err:
         cb->args[0] = h;
         cb->seq = net->dev_base_seq;
         nl_dump_check_consistent(cb, nlmsg_hdr(skb));
+        if (netnsid >= 0)
+                put_net(tgt_net);
 
         return err;
 }
@@ -2360,6 +2400,9 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
         if (err < 0)
                 goto errout;
 
+        if (tb[IFLA_IF_NETNSID])
+                return -EOPNOTSUPP;
+
         if (tb[IFLA_IFNAME])
                 nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
         else
@@ -2454,6 +2497,9 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
         if (err < 0)
                 return err;
 
+        if (tb[IFLA_IF_NETNSID])
+                return -EOPNOTSUPP;
+
         if (tb[IFLA_IFNAME])
                 nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
 
@@ -2585,6 +2631,9 @@ replay:
         if (err < 0)
                 return err;
 
+        if (tb[IFLA_IF_NETNSID])
+                return -EOPNOTSUPP;
+
         if (tb[IFLA_IFNAME])
                 nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
         else
@@ -2818,11 +2867,13 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                         struct netlink_ext_ack *extack)
 {
         struct net *net = sock_net(skb->sk);
+        struct net *tgt_net = net;
         struct ifinfomsg *ifm;
         char ifname[IFNAMSIZ];
         struct nlattr *tb[IFLA_MAX+1];
         struct net_device *dev = NULL;
         struct sk_buff *nskb;
+        int netnsid = -1;
         int err;
         u32 ext_filter_mask = 0;
 
@@ -2830,35 +2881,50 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,
         if (err < 0)
                 return err;
 
+        if (tb[IFLA_IF_NETNSID]) {
+                netnsid = nla_get_s32(tb[IFLA_IF_NETNSID]);
+                tgt_net = get_target_net(skb, netnsid);
+                if (IS_ERR(tgt_net))
+                        return PTR_ERR(tgt_net);
+        }
+
         if (tb[IFLA_IFNAME])
                 nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
 
         if (tb[IFLA_EXT_MASK])
                 ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]);
 
+        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
-                return -EINVAL;
+                goto out;
 
+        err = -ENODEV;
         if (dev == NULL)
-                return -ENODEV;
+                goto out;
 
+        err = -ENOBUFS;
         nskb = nlmsg_new(if_nlmsg_size(dev, ext_filter_mask), GFP_KERNEL);
         if (nskb == NULL)
-                return -ENOBUFS;
+                goto out;
 
-        err = rtnl_fill_ifinfo(nskb, dev, RTM_NEWLINK, NETLINK_CB(skb).portid,
-                               nlh->nlmsg_seq, 0, 0, ext_filter_mask, 0, NULL);
+        err = rtnl_fill_ifinfo(nskb, dev, net,
+                               RTM_NEWLINK, NETLINK_CB(skb).portid,
+                               nlh->nlmsg_seq, 0, 0, ext_filter_mask,
+                               0, NULL, netnsid);
         if (err < 0) {
                 /* -EMSGSIZE implies BUG in if_nlmsg_size */
                 WARN_ON(err == -EMSGSIZE);
                 kfree_skb(nskb);
         } else
                 err = rtnl_unicast(nskb, net, NETLINK_CB(skb).portid);
+out:
+        if (netnsid >= 0)
+                put_net(tgt_net);
 
         return err;
 }
@@ -2948,8 +3014,9 @@ struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev,
         if (skb == NULL)
                 goto errout;
 
-        err = rtnl_fill_ifinfo(skb, dev, type, 0, 0, change, 0, 0, event,
-                               new_nsid);
+        err = rtnl_fill_ifinfo(skb, dev, dev_net(dev),
+                               type, 0, 0, change, 0, 0, event,
+                               new_nsid, -1);
         if (err < 0) {
                 /* -EMSGSIZE implies BUG in if_nlmsg_size() */
                 WARN_ON(err == -EMSGSIZE);