net/ipv6/netfilter/ip6table_security.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * "security" table for IPv6
   4  *
   5  * This is for use by Mandatory Access Control (MAC) security models,
   6  * which need to be able to manage security policy in separate context
   7  * to DAC.
   8  *
   9  * Based on iptable_mangle.c
  10  *
  11  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  12  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam <at> netfilter.org>
  13  * Copyright (C) 2008 Red Hat, Inc., James Morris <jmorris <at> redhat.com>
  14  */
  15 #include <linux/module.h>
  16 #include <linux/netfilter_ipv6/ip6_tables.h>
  17 #include <linux/slab.h>
  18
  19 MODULE_LICENSE("GPL");
  20 MODULE_AUTHOR("James Morris <jmorris <at> redhat.com>");
  21 MODULE_DESCRIPTION("ip6tables security table, for MAC rules");
  22
  23 #define SECURITY_VALID_HOOKS    (1 << NF_INET_LOCAL_IN) | \
  24                                 (1 << NF_INET_FORWARD) | \
  25                                 (1 << NF_INET_LOCAL_OUT)
  26
  27 static int __net_init ip6table_security_table_init(struct net *net);
  28
  29 static const struct xt_table security_table = {
  30         .name           = "security",
  31         .valid_hooks    = SECURITY_VALID_HOOKS,
  32         .me             = THIS_MODULE,
  33         .af             = NFPROTO_IPV6,
  34         .priority       = NF_IP6_PRI_SECURITY,
  35         .table_init     = ip6table_security_table_init,
  36 };
  37
  38 static unsigned int
  39 ip6table_security_hook(void *priv, struct sk_buff *skb,
  40                        const struct nf_hook_state *state)
  41 {
  42         return ip6t_do_table(skb, state, state->net->ipv6.ip6table_security);
  43 }
  44
  45 static struct nf_hook_ops *sectbl_ops __read_mostly;
  46
  47 static int __net_init ip6table_security_table_init(struct net *net)
  48 {
  49         struct ip6t_replace *repl;
  50         int ret;
  51
  52         if (net->ipv6.ip6table_security)
  53                 return 0;
  54
  55         repl = ip6t_alloc_initial_table(&security_table);
  56         if (repl == NULL)
  57                 return -ENOMEM;
  58         ret = ip6t_register_table(net, &security_table, repl, sectbl_ops,
  59                                   &net->ipv6.ip6table_security);
  60         kfree(repl);
  61         return ret;
  62 }
  63
  64 static void __net_exit ip6table_security_net_pre_exit(struct net *net)
  65 {
  66         if (net->ipv6.ip6table_security)
  67                 ip6t_unregister_table_pre_exit(net, net->ipv6.ip6table_security,
  68                                                sectbl_ops);
  69 }
  70
  71 static void __net_exit ip6table_security_net_exit(struct net *net)
  72 {
  73         if (!net->ipv6.ip6table_security)
  74                 return;
  75         ip6t_unregister_table_exit(net, net->ipv6.ip6table_security);
  76         net->ipv6.ip6table_security = NULL;
  77 }
  78
  79 static struct pernet_operations ip6table_security_net_ops = {
  80         .pre_exit = ip6table_security_net_pre_exit,
  81         .exit = ip6table_security_net_exit,
  82 };
  83
  84 static int __init ip6table_security_init(void)
  85 {
  86         int ret;
  87
  88         sectbl_ops = xt_hook_ops_alloc(&security_table, ip6table_security_hook);
  89         if (IS_ERR(sectbl_ops))
  90                 return PTR_ERR(sectbl_ops);
  91
  92         ret = register_pernet_subsys(&ip6table_security_net_ops);
  93         if (ret < 0) {
  94                 kfree(sectbl_ops);
  95                 return ret;
  96         }
  97
  98         ret = ip6table_security_table_init(&init_net);
  99         if (ret) {
 100                 unregister_pernet_subsys(&ip6table_security_net_ops);
 101                 kfree(sectbl_ops);
 102         }
 103         return ret;
 104 }
 105
 106 static void __exit ip6table_security_fini(void)
 107 {
 108         unregister_pernet_subsys(&ip6table_security_net_ops);
 109         kfree(sectbl_ops);
 110 }
 111
 112 module_init(ip6table_security_init);
 113 module_exit(ip6table_security_fini);