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>

2 files changed, 12 insertions, 0 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 6e06e924ed99..417093538916 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -539,6 +539,9 @@ static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg
 
         ASSERT_RTNL();
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv4_policy);
         if (err < 0)
                 goto errout;
@@ -646,6 +649,9 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg
 
         ASSERT_RTNL();
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         ifa = rtm_to_ifaddr(net, nlh);
         if (IS_ERR(ifa))
                 return PTR_ERR(ifa);
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 825c608826de..bce4541c6784 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -613,6 +613,9 @@ static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *ar
         struct fib_table *tb;
         int err;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = rtm_to_fib_config(net, skb, nlh, &cfg);
         if (err < 0)
                 goto errout;
@@ -635,6 +638,9 @@ static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *ar
         struct fib_table *tb;
         int err;
 
+        if (!capable(CAP_NET_ADMIN))
+                return -EPERM;
+
         err = rtm_to_fib_config(net, skb, nlh, &cfg);
         if (err < 0)
                 goto errout;