LXR linux/net/ipv4/netfilter/iptable

   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
  20MODULE_LICENSE("GPL");
  21MODULE_AUTHOR("James Morris <jmorris <at> redhat.com>");
  22MODULE_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
  28static int __net_init iptable_security_table_init(struct net *net);
  29
  30static const struct xt_table security_table = {
  31        .name           = "security",
  32        .valid_hooks    = SECURITY_VALID_HOOKS,
  33        .me             = THIS_MODULE,
  34        .af             = NFPROTO_IPV4,
  35        .priority       = NF_IP_PRI_SECURITY,
  36        .table_init     = iptable_security_table_init,
  37};
  38
  39static unsigned int
  40iptable_security_hook(void *priv, struct sk_buff *skb,
  41                      const struct nf_hook_state *state)
  42{
  43        return ipt_do_table(skb, state, state->net->ipv4.iptable_security);
  44}
  45
  46static struct nf_hook_ops *sectbl_ops __read_mostly;
  47
  48static int __net_init iptable_security_table_init(struct net *net)
  49{
  50        struct ipt_replace *repl;
  51        int ret;
  52
  53        if (net->ipv4.iptable_security)
  54                return 0;
  55
  56        repl = ipt_alloc_initial_table(&security_table);
  57        if (repl == NULL)
  58                return -ENOMEM;
  59        ret = ipt_register_table(net, &security_table, repl, sectbl_ops,
  60                                 &net->ipv4.iptable_security);
  61        kfree(repl);
  62        return ret;
  63}
  64
  65static void __net_exit iptable_security_net_pre_exit(struct net *net)
  66{
  67        if (net->ipv4.iptable_security)
  68                ipt_unregister_table_pre_exit(net, net->ipv4.iptable_security,
  69                                              sectbl_ops);
  70}
  71
  72static void __net_exit iptable_security_net_exit(struct net *net)
  73{
  74        if (!net->ipv4.iptable_security)
  75                return;
  76        ipt_unregister_table_exit(net, net->ipv4.iptable_security);
  77        net->ipv4.iptable_security = NULL;
  78}
  79
  80static struct pernet_operations iptable_security_net_ops = {
  81        .pre_exit = iptable_security_net_pre_exit,
  82        .exit = iptable_security_net_exit,
  83};
  84
  85static int __init iptable_security_init(void)
  86{
  87        int ret;
  88
  89        sectbl_ops = xt_hook_ops_alloc(&security_table, iptable_security_hook);
  90        if (IS_ERR(sectbl_ops))
  91                return PTR_ERR(sectbl_ops);
  92
  93        ret = register_pernet_subsys(&iptable_security_net_ops);
  94        if (ret < 0) {
  95                kfree(sectbl_ops);
  96                return ret;
  97        }
  98
  99        ret = iptable_security_table_init(&init_net);
 100        if (ret) {
 101                unregister_pernet_subsys(&iptable_security_net_ops);
 102                kfree(sectbl_ops);
 103        }
 104
 105        return ret;
 106}
 107
 108static void __exit iptable_security_fini(void)
 109{
 110        unregister_pernet_subsys(&iptable_security_net_ops);
 111        kfree(sectbl_ops);
 112}
 113
 114module_init(iptable_security_init);
 115module_exit(iptable_security_fini);
 116