net/ipv4/netfilter/iptable_security.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * "security" table
   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_ipv4/ip_tables.h>
  17 #include <linux/slab.h>
  18 #include <net/ip.h>
  19
  20 MODULE_LICENSE("GPL");
  21 MODULE_AUTHOR("James Morris <jmorris <at> redhat.com>");
  22 MODULE_DESCRIPTION("iptables security table, for MAC rules");
  23
  24 #define SECURITY_VALID_HOOKS    (1 << NF_INET_LOCAL_IN) | \
  25                                 (1 << NF_INET_FORWARD) | \
  26                                 (1 << NF_INET_LOCAL_OUT)
  27
  28 static const struct xt_table security_table = {
  29         .name           = "security",
  30         .valid_hooks    = SECURITY_VALID_HOOKS,
  31         .me             = THIS_MODULE,
  32         .af             = NFPROTO_IPV4,
  33         .priority       = NF_IP_PRI_SECURITY,
  34 };
  35
  36 static struct nf_hook_ops *sectbl_ops __read_mostly;
  37
  38 static int iptable_security_table_init(struct net *net)
  39 {
  40         struct ipt_replace *repl;
  41         int ret;
  42
  43         repl = ipt_alloc_initial_table(&security_table);
  44         if (repl == NULL)
  45                 return -ENOMEM;
  46         ret = ipt_register_table(net, &security_table, repl, sectbl_ops);
  47         kfree(repl);
  48         return ret;
  49 }
  50
  51 static void __net_exit iptable_security_net_pre_exit(struct net *net)
  52 {
  53         ipt_unregister_table_pre_exit(net, "security");
  54 }
  55
  56 static void __net_exit iptable_security_net_exit(struct net *net)
  57 {
  58         ipt_unregister_table_exit(net, "security");
  59 }
  60
  61 static struct pernet_operations iptable_security_net_ops = {
  62         .pre_exit = iptable_security_net_pre_exit,
  63         .exit = iptable_security_net_exit,
  64 };
  65
  66 static int __init iptable_security_init(void)
  67 {
  68         int ret = xt_register_template(&security_table,
  69                                        iptable_security_table_init);
  70
  71         if (ret < 0)
  72                 return ret;
  73
  74         sectbl_ops = xt_hook_ops_alloc(&security_table, ipt_do_table);
  75         if (IS_ERR(sectbl_ops)) {
  76                 xt_unregister_template(&security_table);
  77                 return PTR_ERR(sectbl_ops);
  78         }
  79
  80         ret = register_pernet_subsys(&iptable_security_net_ops);
  81         if (ret < 0) {
  82                 xt_unregister_template(&security_table);
  83                 kfree(sectbl_ops);
  84                 return ret;
  85         }
  86
  87         return ret;
  88 }
  89
  90 static void __exit iptable_security_fini(void)
  91 {
  92         unregister_pernet_subsys(&iptable_security_net_ops);
  93         kfree(sectbl_ops);
  94         xt_unregister_template(&security_table);
  95 }
  96
  97 module_init(iptable_security_init);
  98 module_exit(iptable_security_fini);