1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2003+ Evgeniy Polyakov <zbr@ioremap.net>
4  */
5 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 
9 #include <linux/capability.h>
10 #include <linux/if.h>
11 #include <linux/inetdevice.h>
12 #include <linux/ip.h>
13 #include <linux/list.h>
14 #include <linux/rculist.h>
15 #include <linux/skbuff.h>
16 #include <linux/slab.h>
17 #include <linux/tcp.h>
18 
19 #include <net/ip.h>
20 #include <net/tcp.h>
21 
22 #include <linux/netfilter/nfnetlink.h>
23 #include <linux/netfilter/x_tables.h>
24 #include <net/netfilter/nf_log.h>
25 #include <linux/netfilter/xt_osf.h>
26 
27 static bool
xt_osf_match_packet(const struct sk_buff * skb,struct xt_action_param * p)28 xt_osf_match_packet(const struct sk_buff *skb, struct xt_action_param *p)
29 {
30 	return nf_osf_match(skb, xt_family(p), xt_hooknum(p), xt_in(p),
31 			    xt_out(p), p->matchinfo, xt_net(p), nf_osf_fingers);
32 }
33 
34 static struct xt_match xt_osf_match = {
35 	.name 		= "osf",
36 	.revision	= 0,
37 	.family		= NFPROTO_IPV4,
38 	.proto		= IPPROTO_TCP,
39 	.hooks      	= (1 << NF_INET_LOCAL_IN) |
40 				(1 << NF_INET_PRE_ROUTING) |
41 				(1 << NF_INET_FORWARD),
42 	.match 		= xt_osf_match_packet,
43 	.matchsize	= sizeof(struct xt_osf_info),
44 	.me		= THIS_MODULE,
45 };
46 
xt_osf_init(void)47 static int __init xt_osf_init(void)
48 {
49 	int err;
50 
51 	err = xt_register_match(&xt_osf_match);
52 	if (err) {
53 		pr_err("Failed to register OS fingerprint "
54 		       "matching module (%d)\n", err);
55 		return err;
56 	}
57 
58 	return 0;
59 }
60 
xt_osf_fini(void)61 static void __exit xt_osf_fini(void)
62 {
63 	xt_unregister_match(&xt_osf_match);
64 }
65 
66 module_init(xt_osf_init);
67 module_exit(xt_osf_fini);
68 
69 MODULE_LICENSE("GPL");
70 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
71 MODULE_DESCRIPTION("Passive OS fingerprint matching.");
72 MODULE_ALIAS("ipt_osf");
73 MODULE_ALIAS("ip6t_osf");
74 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_OSF);
75