[NET] sysctl: make the sys.net.core sysctls per-namespace

Making them per-namespace is required for the following
two reasons:

 First, some ctl values have a per-namespace meaning.
 Second, making them writable from the sub-namespace
 is an isolation hole.

So I introduce the pernet operations to create these
tables. For init_net I use the existing statically
declared tables, for sub-namespace they are duplicated
and the write bits are removed from the mode.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index f97b2a4469ae..d5936115d972 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -37,6 +37,9 @@ struct net {
 
         struct sock             *rtnl;                  /* rtnetlink socket */
 
+        /* core sysctls */
+        struct ctl_table_header *sysctl_core_hdr;
+
         /* List of all packet sockets. */
         rwlock_t                packet_sklist_lock;
         struct hlist_head       packet_sklist;