net: Push capable(CAP_NET_ADMIN) into the rtnl methods

- In rtnetlink_rcv_msg convert the capable(CAP_NET_ADMIN) check
  to ns_capable(net->user-ns, CAP_NET_ADMIN).  Allowing unprivileged
  users to make netlink calls to modify their local network
  namespace.

- In the rtnetlink doit methods add capable(CAP_NET_ADMIN) so
  that calls that are not safe for unprivileged users are still
  protected.

Later patches will remove the extra capable calls from methods
that are safe for unprivilged users.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 31 insertions, 1 deletions

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 58a4ba27dfe3..bf5b5b8af56e 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -275,6 +275,9 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
         struct nlattr *tb[FRA_MAX+1];
         int err = -EINVAL, unresolved = 0;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
                 goto errout;
 
@@ -424,6 +427,9 @@ static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
         struct nlattr *tb[FRA_MAX+1];
         int err = -EINVAL;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
                 goto errout;
 
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index f1c0c2e9cad5..7adcdaf91c4d 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1620,6 +1620,9 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         struct net_device *dev = NULL;
         int err = -EINVAL;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         ASSERT_RTNL();
         if (nlmsg_len(nlh) < sizeof(*ndm))
                 goto out;
@@ -1684,6 +1687,9 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         struct net_device *dev = NULL;
         int err;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         ASSERT_RTNL();
         err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL);
         if (err < 0)
@@ -1962,6 +1968,9 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         struct nlattr *tb[NDTA_MAX+1];
         int err;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = nlmsg_parse(nlh, sizeof(*ndtmsg), tb, NDTA_MAX,
                           nl_neightbl_policy);
         if (err < 0)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a810f6a61372..a40c10b96f47 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1547,6 +1547,9 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         struct nlattr *tb[IFLA_MAX+1];
         char ifname[IFNAMSIZ];
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy);
         if (err < 0)
                 goto errout;
@@ -1590,6 +1593,9 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         int err;
         LIST_HEAD(list_kill);
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy);
         if (err < 0)
                 return err;
@@ -1720,6 +1726,9 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         struct nlattr *linkinfo[IFLA_INFO_MAX+1];
         int err;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
 #ifdef CONFIG_MODULES
 replay:
 #endif
@@ -2057,6 +2066,9 @@ static int rtnl_fdb_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         u8 *addr;
         int err;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL);
         if (err < 0)
                 return err;
@@ -2123,6 +2135,9 @@ static int rtnl_fdb_del(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         int err = -EINVAL;
         __u8 *addr;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         if (nlmsg_len(nlh) < sizeof(*ndm))
                 return -EINVAL;
 
@@ -2488,7 +2503,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
         sz_idx = type>>2;
         kind = type&3;
 
-        if (kind != 2 && !capable(CAP_NET_ADMIN))
+        if (kind != 2 && !ns_capable(net->user_ns, CAP_NET_ADMIN))
                 return -EPERM;
 
         if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {