ipv6: enable net.ipv6.route.max_size sysctl in network namespace

We want to increase route cache size in network namespace
created with user namespace. Currently ipv6 route settings
are disabled for non-initial network namespaces.
We can allow this sysctl and it will be safe since
commit <6126891c> because route cache account to kmem,
that is why users from user namespace can not DOS system.
Signed-off-by: Alexander Kuznetsov <wwfq@yandex-team.ru>
Acked-by: Dmitry Yakunin <zeil@yandex-team.ru>
Acked-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -6306,11 +6306,11 @@ static int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
 
 static struct ctl_table ipv6_route_table_template[] = {
 	{
-		.procname	=	"flush",
-		.data		=	&init_net.ipv6.sysctl.flush_delay,
+		.procname	=	"max_size",
+		.data		=	&init_net.ipv6.sysctl.ip6_rt_max_size,
 		.maxlen		=	sizeof(int),
-		.mode		=	0200,
-		.proc_handler	=	ipv6_sysctl_rtcache_flush
+		.mode		=	0644,
+		.proc_handler	=	proc_dointvec,
 	},
 	{
 		.procname	=	"gc_thresh",
@@ -6320,11 +6320,11 @@ static struct ctl_table ipv6_route_table_template[] = {
 		.proc_handler	=	proc_dointvec,
 	},
 	{
-		.procname	=	"max_size",
-		.data		=	&init_net.ipv6.sysctl.ip6_rt_max_size,
+		.procname	=	"flush",
+		.data		=	&init_net.ipv6.sysctl.flush_delay,
 		.maxlen		=	sizeof(int),
-		.mode		=	0644,
-		.proc_handler	=	proc_dointvec,
+		.mode		=	0200,
+		.proc_handler	=	ipv6_sysctl_rtcache_flush
 	},
 	{
 		.procname	=	"gc_min_interval",
@@ -6396,10 +6396,10 @@ struct ctl_table * __net_init ipv6_route_sysctl_init(struct net *net)
 			GFP_KERNEL);
 
 	if (table) {
-		table[0].data = &net->ipv6.sysctl.flush_delay;
-		table[0].extra1 = net;
+		table[0].data = &net->ipv6.sysctl.ip6_rt_max_size;
 		table[1].data = &net->ipv6.ip6_dst_ops.gc_thresh;
-		table[2].data = &net->ipv6.sysctl.ip6_rt_max_size;
+		table[2].data = &net->ipv6.sysctl.flush_delay;
+		table[2].extra1 = net;
 		table[3].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
 		table[4].data = &net->ipv6.sysctl.ip6_rt_gc_timeout;
 		table[5].data = &net->ipv6.sysctl.ip6_rt_gc_interval;
@@ -6411,7 +6411,7 @@ struct ctl_table * __net_init ipv6_route_sysctl_init(struct net *net)
 
 		/* Don't export sysctls to unprivileged users */
 		if (net->user_ns != &init_user_ns)
-			table[0].procname = NULL;
+			table[1].procname = NULL;
 	}
 
 	return table;