[NETNS][IPV6]: Make multiple instance of sysctl tables.

Each network namespace wants its own set of sysctl value, eg. we
should not be able from a namespace to set a sysctl value for another
namespace , especially for the initial network namespace.

This patch duplicates the sysctl table when we register a new network
namespace for ipv6. The duplicated table are postfixed with the
"template" word to notify the developper the table is cloned.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 89 insertions, 14 deletions

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 3e086f8bb449..5519035491e7 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -619,8 +619,8 @@ static inline int snmp6_unregister_dev(struct inet6_dev *idev)
 #endif
 
 #ifdef CONFIG_SYSCTL
-extern ctl_table ipv6_route_table[];
-extern ctl_table ipv6_icmp_table[];
+extern ctl_table ipv6_route_table_template[];
+extern ctl_table ipv6_icmp_table_template[];
 
 extern int ipv6_sysctl_register(void);
 extern void ipv6_sysctl_unregister(void);
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 6f82046e3013..58fbf30d9fdb 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -5,6 +5,15 @@
 #ifndef __NETNS_IPV6_H__
 #define __NETNS_IPV6_H__
 
+struct ctl_table_header;
+
+struct netns_sysctl_ipv6 {
+#ifdef CONFIG_SYSCTL
+        struct ctl_table_header *table;
+#endif
+};
+
 struct netns_ipv6 {
+        struct netns_sysctl_ipv6 sysctl;
 };
 #endif
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index c3bbd8687307..dfe3b37c43e9 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -907,7 +907,7 @@ int icmpv6_err_convert(int type, int code, int *err)
 EXPORT_SYMBOL(icmpv6_err_convert);
 
 #ifdef CONFIG_SYSCTL
-ctl_table ipv6_icmp_table[] = {
+ctl_table ipv6_icmp_table_template[] = {
         {
                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
                 .procname       = "ratelimit",
@@ -918,5 +918,15 @@ ctl_table ipv6_icmp_table[] = {
         },
         { .ctl_name = 0 },
 };
+
+struct ctl_table *ipv6_icmp_sysctl_init(struct net *net)
+{
+        struct ctl_table *table;
+
+        table = kmemdup(ipv6_icmp_table_template,
+                        sizeof(ipv6_icmp_table_template),
+                        GFP_KERNEL);
+        return table;
+}
 #endif
 
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b80ef5784207..0c7382f4fb85 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2409,7 +2409,7 @@ int ipv6_sysctl_rtcache_flush(ctl_table *ctl, int write, struct file * filp,
                 return -EINVAL;
 }
 
-ctl_table ipv6_route_table[] = {
+ctl_table ipv6_route_table_template[] = {
         {
                 .procname       =       "flush",
                 .data           =       &flush_delay,
@@ -2499,6 +2499,15 @@ ctl_table ipv6_route_table[] = {
         { .ctl_name = 0 }
 };
 
+struct ctl_table *ipv6_route_sysctl_init(struct net *net)
+{
+        struct ctl_table *table;
+
+        table = kmemdup(ipv6_route_table_template,
+                        sizeof(ipv6_route_table_template),
+                        GFP_KERNEL);
+        return table;
+}
 #endif
 
 int __init ip6_route_init(void)
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 7329decf1f9d..7970f3366f87 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -14,20 +14,23 @@
 #include <net/addrconf.h>
 #include <net/inet_frag.h>
 
-static ctl_table ipv6_table[] = {
+extern struct ctl_table *ipv6_route_sysctl_init(struct net *net);
+extern struct ctl_table *ipv6_icmp_sysctl_init(struct net *net);
+
+static ctl_table ipv6_table_template[] = {
         {
                 .ctl_name       = NET_IPV6_ROUTE,
                 .procname       = "route",
                 .maxlen         = 0,
                 .mode           = 0555,
-                .child          = ipv6_route_table
+                .child          = ipv6_route_table_template
         },
         {
                 .ctl_name       = NET_IPV6_ICMP,
                 .procname       = "icmp",
                 .maxlen         = 0,
                 .mode           = 0555,
-                .child          = ipv6_icmp_table
+                .child          = ipv6_icmp_table_template
         },
         {
                 .ctl_name       = NET_IPV6_BINDV6ONLY,
@@ -89,22 +92,66 @@ struct ctl_path net_ipv6_ctl_path[] = {
 };
 EXPORT_SYMBOL_GPL(net_ipv6_ctl_path);
 
-static struct ctl_table_header *ipv6_sysctl_header;
-
 static int ipv6_sysctl_net_init(struct net *net)
 {
-        ipv6_sysctl_header = register_net_sysctl_table(net, net_ipv6_ctl_path,
-                                                       ipv6_table);
-        if (!ipv6_sysctl_header)
+        struct ctl_table *ipv6_table;
+        struct ctl_table *ipv6_route_table;
+        struct ctl_table *ipv6_icmp_table;
+        int err;
+
+        err = -ENOMEM;
+        ipv6_table = kmemdup(ipv6_table_template, sizeof(ipv6_table_template),
+                             GFP_KERNEL);
+        if (!ipv6_table)
+                goto out;
+
+        ipv6_route_table = ipv6_route_sysctl_init(net);
+        if (!ipv6_route_table)
+                goto out_ipv6_table;
+
+        ipv6_icmp_table = ipv6_icmp_sysctl_init(net);
+        if (!ipv6_icmp_table)
+                goto out_ipv6_route_table;
+
+        ipv6_table[0].child = ipv6_route_table;
+        ipv6_table[1].child = ipv6_icmp_table;
+
+        net->ipv6.sysctl.table = register_net_sysctl_table(net, net_ipv6_ctl_path,
+                                                           ipv6_table);
+        if (!net->ipv6.sysctl.table)
                 return -ENOMEM;
 
-        return 0;
+        if (!net->ipv6.sysctl.table)
+                goto out_ipv6_icmp_table;
+
+        err = 0;
+out:
+        return err;
 
+out_ipv6_icmp_table:
+        kfree(ipv6_icmp_table);
+out_ipv6_route_table:
+        kfree(ipv6_route_table);
+out_ipv6_table:
+        kfree(ipv6_table);
+        goto out;
 }
 
 static void ipv6_sysctl_net_exit(struct net *net)
 {
-        unregister_net_sysctl_table(ipv6_sysctl_header);
+        struct ctl_table *ipv6_table;
+        struct ctl_table *ipv6_route_table;
+        struct ctl_table *ipv6_icmp_table;
+
+        ipv6_table = net->ipv6.sysctl.table->ctl_table_arg;
+        ipv6_route_table = ipv6_table[0].child;
+        ipv6_icmp_table = ipv6_table[1].child;
+
+        unregister_net_sysctl_table(net->ipv6.sysctl.table);
+
+        kfree(ipv6_table);
+        kfree(ipv6_route_table);
+        kfree(ipv6_icmp_table);
 }
 
 static struct pernet_operations ipv6_sysctl_net_ops = {