1 /* String matching match for iptables
3 * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/skbuff.h>
14 #include <linux/netfilter/x_tables.h>
15 #include <linux/netfilter/xt_string.h>
16 #include <linux/textsearch.h>
18 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
19 MODULE_DESCRIPTION("Xtables: string-based matching");
20 MODULE_LICENSE("GPL");
21 MODULE_ALIAS("ipt_string");
22 MODULE_ALIAS("ip6t_string");
25 string_mt(const struct sk_buff *skb, const struct xt_match_param *par)
27 const struct xt_string_info *conf = par->matchinfo;
28 struct ts_state state;
31 memset(&state, 0, sizeof(struct ts_state));
33 invert = (par->match->revision == 0 ? conf->u.v0.invert :
34 conf->u.v1.flags & XT_STRING_FLAG_INVERT);
36 return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
37 conf->to_offset, conf->config, &state)
38 != UINT_MAX) ^ invert;
41 #define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m))
43 static bool string_mt_check(const struct xt_mtchk_param *par)
45 struct xt_string_info *conf = par->matchinfo;
46 struct ts_config *ts_conf;
47 int flags = TS_AUTOLOAD;
49 /* Damn, can't handle this case properly with iptables... */
50 if (conf->from_offset > conf->to_offset)
52 if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')
54 if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)
56 if (par->match->revision == 1) {
57 if (conf->u.v1.flags &
58 ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT))
60 if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE)
61 flags |= TS_IGNORECASE;
63 ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
68 conf->config = ts_conf;
73 static void string_mt_destroy(const struct xt_mtdtor_param *par)
75 textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config);
78 static struct xt_match xt_string_mt_reg[] __read_mostly = {
82 .family = NFPROTO_UNSPEC,
83 .checkentry = string_mt_check,
85 .destroy = string_mt_destroy,
86 .matchsize = sizeof(struct xt_string_info),
92 .family = NFPROTO_UNSPEC,
93 .checkentry = string_mt_check,
95 .destroy = string_mt_destroy,
96 .matchsize = sizeof(struct xt_string_info),
101 static int __init string_mt_init(void)
103 return xt_register_matches(xt_string_mt_reg,
104 ARRAY_SIZE(xt_string_mt_reg));
107 static void __exit string_mt_exit(void)
109 xt_unregister_matches(xt_string_mt_reg, ARRAY_SIZE(xt_string_mt_reg));
112 module_init(string_mt_init);
113 module_exit(string_mt_exit);