net/netfilter/xt_osf.c

   1 /*
   2  * Copyright (c) 2003+ Evgeniy Polyakov <zbr@ioremap.net>
   3  *
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21
  22 #include <linux/capability.h>
  23 #include <linux/if.h>
  24 #include <linux/inetdevice.h>
  25 #include <linux/ip.h>
  26 #include <linux/list.h>
  27 #include <linux/rculist.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/slab.h>
  30 #include <linux/tcp.h>
  31
  32 #include <net/ip.h>
  33 #include <net/tcp.h>
  34
  35 #include <linux/netfilter/nfnetlink.h>
  36 #include <linux/netfilter/x_tables.h>
  37 #include <net/netfilter/nf_log.h>
  38 #include <linux/netfilter/xt_osf.h>
  39
  40 static bool
  41 xt_osf_match_packet(const struct sk_buff *skb, struct xt_action_param *p)
  42 {
  43         const struct xt_osf_info *info = p->matchinfo;
  44         struct net *net = xt_net(p);
  45
  46         if (!info)
  47                 return false;
  48
  49         return nf_osf_match(skb, xt_family(p), xt_hooknum(p), xt_in(p),
  50                             xt_out(p), info, net, nf_osf_fingers);
  51 }
  52
  53 static struct xt_match xt_osf_match = {
  54         .name           = "osf",
  55         .revision       = 0,
  56         .family         = NFPROTO_IPV4,
  57         .proto          = IPPROTO_TCP,
  58         .hooks          = (1 << NF_INET_LOCAL_IN) |
  59                                 (1 << NF_INET_PRE_ROUTING) |
  60                                 (1 << NF_INET_FORWARD),
  61         .match          = xt_osf_match_packet,
  62         .matchsize      = sizeof(struct xt_osf_info),
  63         .me             = THIS_MODULE,
  64 };
  65
  66 static int __init xt_osf_init(void)
  67 {
  68         int err;
  69
  70         err = xt_register_match(&xt_osf_match);
  71         if (err) {
  72                 pr_err("Failed to register OS fingerprint "
  73                        "matching module (%d)\n", err);
  74                 return err;
  75         }
  76
  77         return 0;
  78 }
  79
  80 static void __exit xt_osf_fini(void)
  81 {
  82         xt_unregister_match(&xt_osf_match);
  83 }
  84
  85 module_init(xt_osf_init);
  86 module_exit(xt_osf_fini);
  87
  88 MODULE_LICENSE("GPL");
  89 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
  90 MODULE_DESCRIPTION("Passive OS fingerprint matching.");
  91 MODULE_ALIAS("ipt_osf");
  92 MODULE_ALIAS("ip6t_osf");
  93 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_OSF);