1 files changed, 30 insertions, 1 deletions

diff --git a/net/sysctl_net.c b/net/sysctl_net.c
index b4f0525f91af..007c1a6708ee 100644
--- a/net/sysctl_net.c
+++ b/net/sysctl_net.c
@@ -4,7 +4,6 @@
  * Begun April 1, 1996, Mike Shaver.
  * Added /proc/sys/net directories for each protocol family. [MS]
  *
- * $Log: sysctl_net.c,v $
  * Revision 1.2  1996/05/08  20:24:40  shaver
  * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
  * NET_IPV4_IP_FORWARD.
@@ -40,6 +39,27 @@ static struct ctl_table_root net_sysctl_root = {
         .lookup = net_ctl_header_lookup,
 };
 
+static LIST_HEAD(net_sysctl_ro_tables);
+static struct list_head *net_ctl_ro_header_lookup(struct ctl_table_root *root,
+                struct nsproxy *namespaces)
+{
+        return &net_sysctl_ro_tables;
+}
+
+static int net_ctl_ro_header_perms(struct ctl_table_root *root,
+                struct nsproxy *namespaces, struct ctl_table *table)
+{
+        if (namespaces->net_ns == &init_net)
+                return table->mode;
+        else
+                return table->mode & ~0222;
+}
+
+static struct ctl_table_root net_sysctl_ro_root = {
+        .lookup = net_ctl_ro_header_lookup,
+        .permissions = net_ctl_ro_header_perms,
+};
+
 static int sysctl_net_init(struct net *net)
 {
         INIT_LIST_HEAD(&net->sysctl_table_headers);
@@ -64,6 +84,7 @@ static __init int sysctl_init(void)
         if (ret)
                 goto out;
         register_sysctl_root(&net_sysctl_root);
+        register_sysctl_root(&net_sysctl_ro_root);
 out:
         return ret;
 }
@@ -80,6 +101,14 @@ struct ctl_table_header *register_net_sysctl_table(struct net *net,
 }
 EXPORT_SYMBOL_GPL(register_net_sysctl_table);
 
+struct ctl_table_header *register_net_sysctl_rotable(const
+                struct ctl_path *path, struct ctl_table *table)
+{
+        return __register_sysctl_paths(&net_sysctl_ro_root,
+                        &init_nsproxy, path, table);
+}
+EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
+
 void unregister_net_sysctl_table(struct ctl_table_header *header)
 {
         unregister_sysctl_table(header);