[NETFILTER]: x_tables: per-netns xt_tables

In fact all we want is per-netns set of rules, however doing that will
unnecessary complicate routines such as ipt_hook()/ipt_do_table, so
make full xt_table array per-netns.

Every user stubbed with init_net for a while.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/x_tables.h

@@ -335,7 +335,8 @@ extern int xt_check_target(const struct xt_target *target, unsigned short family
 			   unsigned int size, const char *table, unsigned int hook,
 			   unsigned short proto, int inv_proto);
 
-extern struct xt_table *xt_register_table(struct xt_table *table,
+extern struct xt_table *xt_register_table(struct net *net,
+					  struct xt_table *table,
 					  struct xt_table_info *bootstrap,
 					  struct xt_table_info *newinfo);
 extern void *xt_unregister_table(struct xt_table *table);
@@ -352,7 +353,8 @@ extern struct xt_target *xt_request_find_target(int af, const char *name,
 extern int xt_find_revision(int af, const char *name, u8 revision, int target,
 			    int *err);
 
-extern struct xt_table *xt_find_table_lock(int af, const char *name);
+extern struct xt_table *xt_find_table_lock(struct net *net, int af,
+					   const char *name);
 extern void xt_table_unlock(struct xt_table *t);
 
 extern int xt_proto_init(int af);

include/net/net_namespace.h

@@ -12,6 +12,7 @@
 #include <net/netns/packet.h>
 #include <net/netns/ipv4.h>
 #include <net/netns/ipv6.h>
+#include <net/netns/x_tables.h>
 
 struct proc_dir_entry;
 struct net_device;
@@ -56,6 +57,9 @@ struct net {
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	struct netns_ipv6	ipv6;
 #endif
+#ifdef CONFIG_NETFILTER
+	struct netns_xt		xt;
+#endif
 };
 
 #ifdef CONFIG_NET

include/net/netns/x_tables.h

+#ifndef __NETNS_X_TABLES_H
+#define __NETNS_X_TABLES_H
+
+#include <linux/list.h>
+#include <linux/net.h>
+
+struct netns_xt {
+	struct list_head tables[NPROTO];
+};
+#endif

net/ipv4/netfilter/arp_tables.c

@@ -870,7 +870,7 @@ static int get_info(void __user *user, int *len, int compat)
 	if (compat)
 		xt_compat_lock(NF_ARP);
 #endif
-	t = try_then_request_module(xt_find_table_lock(NF_ARP, name),
+	t = try_then_request_module(xt_find_table_lock(&init_net, NF_ARP, name),
 				    "arptable_%s", name);
 	if (t && !IS_ERR(t)) {
 		struct arpt_getinfo info;
@@ -926,7 +926,7 @@ static int get_entries(struct arpt_get_entries __user *uptr, int *len)
 		return -EINVAL;
 	}
 
-	t = xt_find_table_lock(NF_ARP, get.name);
+	t = xt_find_table_lock(&init_net, NF_ARP, get.name);
 	if (t && !IS_ERR(t)) {
 		struct xt_table_info *private = t->private;
 		duprintf("t->private->number = %u\n",
@@ -966,7 +966,7 @@ static int __do_replace(const char *name, unsigned int valid_hooks,
 		goto out;
 	}
 
-	t = try_then_request_module(xt_find_table_lock(NF_ARP, name),
+	t = try_then_request_module(xt_find_table_lock(&init_net, NF_ARP, name),
 				    "arptable_%s", name);
 	if (!t || IS_ERR(t)) {
 		ret = t ? PTR_ERR(t) : -ENOENT;
@@ -1132,7 +1132,7 @@ static int do_add_counters(void __user *user, unsigned int len, int compat)
 		goto free;
 	}
 
-	t = xt_find_table_lock(NF_ARP, name);
+	t = xt_find_table_lock(&init_net, NF_ARP, name);
 	if (!t || IS_ERR(t)) {
 		ret = t ? PTR_ERR(t) : -ENOENT;
 		goto free;
@@ -1604,7 +1604,7 @@ static int compat_get_entries(struct compat_arpt_get_entries __user *uptr,
 	}
 
 	xt_compat_lock(NF_ARP);
-	t = xt_find_table_lock(NF_ARP, get.name);
+	t = xt_find_table_lock(&init_net, NF_ARP, get.name);
 	if (t && !IS_ERR(t)) {
 		struct xt_table_info *private = t->private;
 		struct xt_table_info info;
@@ -1751,7 +1751,7 @@ int arpt_register_table(struct arpt_table *table,
 		return ret;
 	}
 
-	new_table = xt_register_table(table, &bootstrap, newinfo);
+	new_table = xt_register_table(&init_net, table, &bootstrap, newinfo);
 	if (IS_ERR(new_table)) {
 		xt_free_table_info(newinfo);
 		return PTR_ERR(new_table);

net/ipv4/netfilter/ip_tables.c

@@ -1112,7 +1112,7 @@ static int get_info(void __user *user, int *len, int compat)
 	if (compat)
 		xt_compat_lock(AF_INET);
 #endif
-	t = try_then_request_module(xt_find_table_lock(AF_INET, name),
+	t = try_then_request_module(xt_find_table_lock(&init_net, AF_INET, name),
 				    "iptable_%s", name);
 	if (t && !IS_ERR(t)) {
 		struct ipt_getinfo info;
@@ -1170,7 +1170,7 @@ get_entries(struct ipt_get_entries __user *uptr, int *len)
 		return -EINVAL;
 	}
 
-	t = xt_find_table_lock(AF_INET, get.name);
+	t = xt_find_table_lock(&init_net, AF_INET, get.name);
 	if (t && !IS_ERR(t)) {
 		struct xt_table_info *private = t->private;
 		duprintf("t->private->number = %u\n", private->number);
@@ -1208,7 +1208,7 @@ __do_replace(const char *name, unsigned int valid_hooks,
 		goto out;
 	}
 
-	t = try_then_request_module(xt_find_table_lock(AF_INET, name),
+	t = try_then_request_module(xt_find_table_lock(&init_net, AF_INET, name),
 				    "iptable_%s", name);
 	if (!t || IS_ERR(t)) {
 		ret = t ? PTR_ERR(t) : -ENOENT;
@@ -1383,7 +1383,7 @@ do_add_counters(void __user *user, unsigned int len, int compat)
 		goto free;
 	}
 
-	t = xt_find_table_lock(AF_INET, name);
+	t = xt_find_table_lock(&init_net, AF_INET, name);
 	if (!t || IS_ERR(t)) {
 		ret = t ? PTR_ERR(t) : -ENOENT;
 		goto free;
@@ -1924,7 +1924,7 @@ compat_get_entries(struct compat_ipt_get_entries __user *uptr, int *len)
 	}
 
 	xt_compat_lock(AF_INET);
-	t = xt_find_table_lock(AF_INET, get.name);
+	t = xt_find_table_lock(&init_net, AF_INET, get.name);
 	if (t && !IS_ERR(t)) {
 		struct xt_table_info *private = t->private;
 		struct xt_table_info info;
@@ -2075,7 +2075,7 @@ int ipt_register_table(struct xt_table *table, const struct ipt_replace *repl)
 		return ret;
 	}
 
-	new_table = xt_register_table(table, &bootstrap, newinfo);
+	new_table = xt_register_table(&init_net, table, &bootstrap, newinfo);
 	if (IS_ERR(new_table)) {
 		xt_free_table_info(newinfo);
 		return PTR_ERR(new_table);

net/ipv6/netfilter/ip6_tables.c

@@ -1138,7 +1138,7 @@ static int get_info(void __user *user, int *len, int compat)
 	if (compat)
 		xt_compat_lock(AF_INET6);
 #endif
-	t = try_then_request_module(xt_find_table_lock(AF_INET6, name),
+	t = try_then_request_module(xt_find_table_lock(&init_net, AF_INET6, name),
 				    "ip6table_%s", name);
 	if (t && !IS_ERR(t)) {
 		struct ip6t_getinfo info;
@@ -1196,7 +1196,7 @@ get_entries(struct ip6t_get_entries __user *uptr, int *len)
 		return -EINVAL;
 	}
 
-	t = xt_find_table_lock(AF_INET6, get.name);
+	t = xt_find_table_lock(&init_net, AF_INET6, get.name);
 	if (t && !IS_ERR(t)) {
 		struct xt_table_info *private = t->private;
 		duprintf("t->private->number = %u\n", private->number);
@@ -1235,7 +1235,7 @@ __do_replace(const char *name, unsigned int valid_hooks,
 		goto out;
 	}
 
-	t = try_then_request_module(xt_find_table_lock(AF_INET6, name),
+	t = try_then_request_module(xt_find_table_lock(&init_net, AF_INET6, name),
 				    "ip6table_%s", name);
 	if (!t || IS_ERR(t)) {
 		ret = t ? PTR_ERR(t) : -ENOENT;
@@ -1410,7 +1410,7 @@ do_add_counters(void __user *user, unsigned int len, int compat)
 		goto free;
 	}
 
-	t = xt_find_table_lock(AF_INET6, name);
+	t = xt_find_table_lock(&init_net, AF_INET6, name);
 	if (!t || IS_ERR(t)) {
 		ret = t ? PTR_ERR(t) : -ENOENT;
 		goto free;
@@ -1950,7 +1950,7 @@ compat_get_entries(struct compat_ip6t_get_entries __user *uptr, int *len)
 	}
 
 	xt_compat_lock(AF_INET6);
-	t = xt_find_table_lock(AF_INET6, get.name);
+	t = xt_find_table_lock(&init_net, AF_INET6, get.name);
 	if (t && !IS_ERR(t)) {
 		struct xt_table_info *private = t->private;
 		struct xt_table_info info;
@@ -2101,7 +2101,7 @@ int ip6t_register_table(struct xt_table *table, const struct ip6t_replace *repl)
 		return ret;
 	}
 
-	new_table = xt_register_table(table, &bootstrap, newinfo);
+	new_table = xt_register_table(&init_net, table, &bootstrap, newinfo);
 	if (IS_ERR(new_table)) {
 		xt_free_table_info(newinfo);
 		return PTR_ERR(new_table);

net/netfilter/x_tables.c

@@ -44,7 +44,6 @@ struct xt_af {
 	struct mutex mutex;
 	struct list_head match;
 	struct list_head target;
-	struct list_head tables;
 #ifdef CONFIG_COMPAT
 	struct mutex compat_mutex;
 	struct compat_delta *compat_offsets;
@@ -597,14 +596,14 @@ void xt_free_table_info(struct xt_table_info *info)
 EXPORT_SYMBOL(xt_free_table_info);
 
 /* Find table by name, grabs mutex & ref.  Returns ERR_PTR() on error. */
-struct xt_table *xt_find_table_lock(int af, const char *name)
+struct xt_table *xt_find_table_lock(struct net *net, int af, const char *name)
 {
 	struct xt_table *t;
 
 	if (mutex_lock_interruptible(&xt[af].mutex) != 0)
 		return ERR_PTR(-EINTR);
 
-	list_for_each_entry(t, &xt[af].tables, list)
+	list_for_each_entry(t, &net->xt.tables[af], list)
 		if (strcmp(t->name, name) == 0 && try_module_get(t->me))
 			return t;
 	mutex_unlock(&xt[af].mutex);
@@ -660,7 +659,7 @@ xt_replace_table(struct xt_table *table,
 }
 EXPORT_SYMBOL_GPL(xt_replace_table);
 
-struct xt_table *xt_register_table(struct xt_table *table,
+struct xt_table *xt_register_table(struct net *net, struct xt_table *table,
 				   struct xt_table_info *bootstrap,
 				   struct xt_table_info *newinfo)
 {
@@ -673,7 +672,7 @@ struct xt_table *xt_register_table(struct xt_table *table,
 		goto out;
 
 	/* Don't autoload: we'd eat our tail... */
-	list_for_each_entry(t, &xt[table->af].tables, list) {
+	list_for_each_entry(t, &net->xt.tables[table->af], list) {
 		if (strcmp(t->name, table->name) == 0) {
 			ret = -EEXIST;
 			goto unlock;
@@ -692,7 +691,7 @@ struct xt_table *xt_register_table(struct xt_table *table,
 	/* save number of initial entries */
 	private->initial_entries = private->number;
 
-	list_add(&table->list, &xt[table->af].tables);
+	list_add(&table->list, &net->xt.tables[table->af]);
 	mutex_unlock(&xt[table->af].mutex);
 	return table;
 
@@ -744,7 +743,7 @@ static struct list_head *type2list(u_int16_t af, u_int16_t type)
 		list = &xt[af].match;
 		break;
 	case TABLE:
-		list = &xt[af].tables;
+		list = &init_net.xt.tables[af];
 		break;
 	default:
 		list = NULL;
@@ -919,10 +918,22 @@ void xt_proto_fini(int af)
 }
 EXPORT_SYMBOL_GPL(xt_proto_fini);
 
+static int __net_init xt_net_init(struct net *net)
+{
+	int i;
+
+	for (i = 0; i < NPROTO; i++)
+		INIT_LIST_HEAD(&net->xt.tables[i]);
+	return 0;
+}
+
+static struct pernet_operations xt_net_ops = {
+	.init = xt_net_init,
+};
 
 static int __init xt_init(void)
 {
-	int i;
+	int i, rv;
 
 	xt = kmalloc(sizeof(struct xt_af) * NPROTO, GFP_KERNEL);
 	if (!xt)
@@ -936,13 +947,16 @@ static int __init xt_init(void)
 #endif
 		INIT_LIST_HEAD(&xt[i].target);
 		INIT_LIST_HEAD(&xt[i].match);
-		INIT_LIST_HEAD(&xt[i].tables);
 	}
-	return 0;
+	rv = register_pernet_subsys(&xt_net_ops);
+	if (rv < 0)
+		kfree(xt);
+	return rv;
 }
 
 static void __exit xt_fini(void)
 {
+	unregister_pernet_subsys(&xt_net_ops);
 	kfree(xt);
 }