SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/ipv4/netfilter/iptable_security.c

   1 /*
   2  * "security" table
   3  *
   4  * This is for use by Mandatory Access Control (MAC) security models,
   5  * which need to be able to manage security policy in separate context
   6  * to DAC.
   7  *
   8  * Based on iptable_mangle.c
   9  *
  10  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam <at> netfilter.org>
  12  * Copyright (C) 2008 Red Hat, Inc., James Morris <jmorris <at> redhat.com>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2 as
  16  * published by the Free Software Foundation.
  17  */
  18 #include <linux/module.h>
  19 #include <linux/netfilter_ipv4/ip_tables.h>
  20 #include <net/ip.h>
  21
  22 MODULE_LICENSE("GPL");
  23 MODULE_AUTHOR("James Morris <jmorris <at> redhat.com>");
  24 MODULE_DESCRIPTION("iptables security table, for MAC rules");
  25
  26 #define SECURITY_VALID_HOOKS    (1 << NF_INET_LOCAL_IN) | \
  27                                 (1 << NF_INET_FORWARD) | \
  28                                 (1 << NF_INET_LOCAL_OUT)
  29
  30 static const struct
  31 {
  32         struct ipt_replace repl;
  33         struct ipt_standard entries[3];
  34         struct ipt_error term;
  35 } initial_table __net_initdata = {
  36         .repl = {
  37                 .name = "security",
  38                 .valid_hooks = SECURITY_VALID_HOOKS,
  39                 .num_entries = 4,
  40                 .size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
  41                 .hook_entry = {
  42                         [NF_INET_LOCAL_IN]      = 0,
  43                         [NF_INET_FORWARD]       = sizeof(struct ipt_standard),
  44                         [NF_INET_LOCAL_OUT]     = sizeof(struct ipt_standard) * 2,
  45                 },
  46                 .underflow = {
  47                         [NF_INET_LOCAL_IN]      = 0,
  48                         [NF_INET_FORWARD]       = sizeof(struct ipt_standard),
  49                         [NF_INET_LOCAL_OUT]     = sizeof(struct ipt_standard) * 2,
  50                 },
  51         },
  52         .entries = {
  53                 IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_IN */
  54                 IPT_STANDARD_INIT(NF_ACCEPT),   /* FORWARD */
  55                 IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_OUT */
  56         },
  57         .term = IPT_ERROR_INIT,                 /* ERROR */
  58 };
  59
  60 static const struct xt_table security_table = {
  61         .name           = "security",
  62         .valid_hooks    = SECURITY_VALID_HOOKS,
  63         .me             = THIS_MODULE,
  64         .af             = NFPROTO_IPV4,
  65 };
  66
  67 static unsigned int
  68 iptable_security_hook(unsigned int hook, struct sk_buff *skb,
  69                       const struct net_device *in,
  70                       const struct net_device *out,
  71                       int (*okfn)(struct sk_buff *))
  72 {
  73         if (hook == NF_INET_LOCAL_OUT) {
  74                 if (skb->len < sizeof(struct iphdr) ||
  75                     ip_hdrlen(skb) < sizeof(struct iphdr))
  76                         /* Somebody is playing with raw sockets. */
  77                         return NF_ACCEPT;
  78
  79                 return ipt_do_table(skb, hook, in, out,
  80                                     dev_net(out)->ipv4.iptable_security);
  81         }
  82
  83         /* INPUT/FORWARD: */
  84         return ipt_do_table(skb, hook, in, out,
  85                             dev_net(in)->ipv4.iptable_security);
  86 }
  87
  88 static struct nf_hook_ops ipt_ops[] __read_mostly = {
  89         {
  90                 .hook           = iptable_security_hook,
  91                 .owner          = THIS_MODULE,
  92                 .pf             = NFPROTO_IPV4,
  93                 .hooknum        = NF_INET_LOCAL_IN,
  94                 .priority       = NF_IP_PRI_SECURITY,
  95         },
  96         {
  97                 .hook           = iptable_security_hook,
  98                 .owner          = THIS_MODULE,
  99                 .pf             = NFPROTO_IPV4,
 100                 .hooknum        = NF_INET_FORWARD,
 101                 .priority       = NF_IP_PRI_SECURITY,
 102         },
 103         {
 104                 .hook           = iptable_security_hook,
 105                 .owner          = THIS_MODULE,
 106                 .pf             = NFPROTO_IPV4,
 107                 .hooknum        = NF_INET_LOCAL_OUT,
 108                 .priority       = NF_IP_PRI_SECURITY,
 109         },
 110 };
 111
 112 static int __net_init iptable_security_net_init(struct net *net)
 113 {
 114         net->ipv4.iptable_security =
 115                 ipt_register_table(net, &security_table, &initial_table.repl);
 116
 117         if (IS_ERR(net->ipv4.iptable_security))
 118                 return PTR_ERR(net->ipv4.iptable_security);
 119
 120         return 0;
 121 }
 122
 123 static void __net_exit iptable_security_net_exit(struct net *net)
 124 {
 125         ipt_unregister_table(net, net->ipv4.iptable_security);
 126 }
 127
 128 static struct pernet_operations iptable_security_net_ops = {
 129         .init = iptable_security_net_init,
 130         .exit = iptable_security_net_exit,
 131 };
 132
 133 static int __init iptable_security_init(void)
 134 {
 135         int ret;
 136
 137         ret = register_pernet_subsys(&iptable_security_net_ops);
 138         if (ret < 0)
 139                 return ret;
 140
 141         ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
 142         if (ret < 0)
 143                 goto cleanup_table;
 144
 145         return ret;
 146
 147 cleanup_table:
 148         unregister_pernet_subsys(&iptable_security_net_ops);
 149         return ret;
 150 }
 151
 152 static void __exit iptable_security_fini(void)
 153 {
 154         nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
 155         unregister_pernet_subsys(&iptable_security_net_ops);
 156 }
 157
 158 module_init(iptable_security_init);
 159 module_exit(iptable_security_fini);