Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x. |
| 3 | * |
| 4 | * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling |
| 5 | * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | * |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/moduleparam.h> |
| 15 | #include <linux/netfilter_ipv4/ip_tables.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 16 | #include <linux/slab.h> |
Arnaldo Carvalho de Melo | c9bdd4b | 2007-03-12 20:09:15 -0300 | [diff] [blame] | 17 | #include <net/ip.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | |
| 19 | MODULE_LICENSE("GPL"); |
| 20 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| 21 | MODULE_DESCRIPTION("iptables filter table"); |
| 22 | |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame] | 23 | #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \ |
| 24 | (1 << NF_INET_FORWARD) | \ |
| 25 | (1 << NF_INET_LOCAL_OUT)) |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 26 | static int __net_init iptable_filter_table_init(struct net *net); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | |
Jan Engelhardt | 35aad0f | 2009-08-24 14:56:30 +0200 | [diff] [blame] | 28 | static const struct xt_table packet_filter = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | .name = "filter", |
| 30 | .valid_hooks = FILTER_VALID_HOOKS, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 31 | .me = THIS_MODULE, |
Jan Engelhardt | f88e6a8 | 2009-06-13 06:25:44 +0200 | [diff] [blame] | 32 | .af = NFPROTO_IPV4, |
Jan Engelhardt | 2b95efe | 2009-06-17 13:57:48 +0200 | [diff] [blame] | 33 | .priority = NF_IP_PRI_FILTER, |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 34 | .table_init = iptable_filter_table_init, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | }; |
| 36 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | static unsigned int |
Eric W. Biederman | 06198b3 | 2015-09-18 14:33:06 -0500 | [diff] [blame] | 38 | iptable_filter_hook(void *priv, struct sk_buff *skb, |
David S. Miller | 238e54c | 2015-04-03 20:32:56 -0400 | [diff] [blame] | 39 | const struct nf_hook_state *state) |
Alexey Dobriyan | 666953df | 2008-04-14 09:56:02 +0200 | [diff] [blame] | 40 | { |
Eric W. Biederman | 6cb8ff3f1 | 2015-09-18 14:32:55 -0500 | [diff] [blame] | 41 | if (state->hook == NF_INET_LOCAL_OUT && |
Jan Engelhardt | 2b21e05 | 2009-06-13 06:57:10 +0200 | [diff] [blame] | 42 | (skb->len < sizeof(struct iphdr) || |
| 43 | ip_hdrlen(skb) < sizeof(struct iphdr))) |
| 44 | /* root is playing with raw sockets. */ |
| 45 | return NF_ACCEPT; |
Jan Engelhardt | 737535c | 2009-06-13 06:46:36 +0200 | [diff] [blame] | 46 | |
Eric W. Biederman | 6cb8ff3f1 | 2015-09-18 14:32:55 -0500 | [diff] [blame] | 47 | return ipt_do_table(skb, state, state->net->ipv4.iptable_filter); |
Alexey Dobriyan | 666953df | 2008-04-14 09:56:02 +0200 | [diff] [blame] | 48 | } |
| 49 | |
Jan Engelhardt | 2b95efe | 2009-06-17 13:57:48 +0200 | [diff] [blame] | 50 | static struct nf_hook_ops *filter_ops __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | |
| 52 | /* Default to forward because I got too much mail already. */ |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 53 | static bool forward __read_mostly = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | module_param(forward, bool, 0000); |
| 55 | |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 56 | static int __net_init iptable_filter_table_init(struct net *net) |
Alexey Dobriyan | 9335f04 | 2008-01-31 04:03:23 -0800 | [diff] [blame] | 57 | { |
Jan Engelhardt | e3eaa99 | 2009-06-17 22:14:54 +0200 | [diff] [blame] | 58 | struct ipt_replace *repl; |
Florian Westphal | a67dd26 | 2016-02-25 10:08:35 +0100 | [diff] [blame] | 59 | int err; |
Jan Engelhardt | e3eaa99 | 2009-06-17 22:14:54 +0200 | [diff] [blame] | 60 | |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 61 | if (net->ipv4.iptable_filter) |
| 62 | return 0; |
| 63 | |
Jan Engelhardt | e3eaa99 | 2009-06-17 22:14:54 +0200 | [diff] [blame] | 64 | repl = ipt_alloc_initial_table(&packet_filter); |
| 65 | if (repl == NULL) |
| 66 | return -ENOMEM; |
| 67 | /* Entry 1 is the FORWARD hook */ |
| 68 | ((struct ipt_standard *)repl->entries)[1].target.verdict = |
Rusty Russell | 523f610 | 2012-03-22 12:27:06 +0000 | [diff] [blame] | 69 | forward ? -NF_ACCEPT - 1 : -NF_DROP - 1; |
Jan Engelhardt | e3eaa99 | 2009-06-17 22:14:54 +0200 | [diff] [blame] | 70 | |
Florian Westphal | a67dd26 | 2016-02-25 10:08:35 +0100 | [diff] [blame] | 71 | err = ipt_register_table(net, &packet_filter, repl, filter_ops, |
| 72 | &net->ipv4.iptable_filter); |
Jan Engelhardt | e3eaa99 | 2009-06-17 22:14:54 +0200 | [diff] [blame] | 73 | kfree(repl); |
Florian Westphal | a67dd26 | 2016-02-25 10:08:35 +0100 | [diff] [blame] | 74 | return err; |
Alexey Dobriyan | 9335f04 | 2008-01-31 04:03:23 -0800 | [diff] [blame] | 75 | } |
| 76 | |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 77 | static int __net_init iptable_filter_net_init(struct net *net) |
| 78 | { |
| 79 | if (net == &init_net || !forward) |
| 80 | return iptable_filter_table_init(net); |
| 81 | |
| 82 | return 0; |
| 83 | } |
| 84 | |
Alexey Dobriyan | 9335f04 | 2008-01-31 04:03:23 -0800 | [diff] [blame] | 85 | static void __net_exit iptable_filter_net_exit(struct net *net) |
| 86 | { |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 87 | if (!net->ipv4.iptable_filter) |
| 88 | return; |
Florian Westphal | a67dd26 | 2016-02-25 10:08:35 +0100 | [diff] [blame] | 89 | ipt_unregister_table(net, net->ipv4.iptable_filter, filter_ops); |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 90 | net->ipv4.iptable_filter = NULL; |
Alexey Dobriyan | 9335f04 | 2008-01-31 04:03:23 -0800 | [diff] [blame] | 91 | } |
| 92 | |
| 93 | static struct pernet_operations iptable_filter_net_ops = { |
| 94 | .init = iptable_filter_net_init, |
| 95 | .exit = iptable_filter_net_exit, |
| 96 | }; |
| 97 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 98 | static int __init iptable_filter_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | { |
| 100 | int ret; |
| 101 | |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 102 | filter_ops = xt_hook_ops_alloc(&packet_filter, iptable_filter_hook); |
| 103 | if (IS_ERR(filter_ops)) |
| 104 | return PTR_ERR(filter_ops); |
| 105 | |
Alexey Dobriyan | 9335f04 | 2008-01-31 04:03:23 -0800 | [diff] [blame] | 106 | ret = register_pernet_subsys(&iptable_filter_net_ops); |
| 107 | if (ret < 0) |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 108 | kfree(filter_ops); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | } |
| 112 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 113 | static void __exit iptable_filter_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | { |
Alexey Dobriyan | 9335f04 | 2008-01-31 04:03:23 -0800 | [diff] [blame] | 115 | unregister_pernet_subsys(&iptable_filter_net_ops); |
Florian Westphal | b9e69e1 | 2016-02-25 10:08:36 +0100 | [diff] [blame] | 116 | kfree(filter_ops); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | } |
| 118 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 119 | module_init(iptable_filter_init); |
| 120 | module_exit(iptable_filter_fini); |