1// SPDX-License-Identifier: GPL-2.0-only
 2/* String matching match for iptables
 3 *
 4 * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
 
 
 
 
 5 */
 6
 7#include <linux/gfp.h>
 8#include <linux/init.h>
 9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/skbuff.h>
12#include <linux/netfilter/x_tables.h>
13#include <linux/netfilter/xt_string.h>
14#include <linux/textsearch.h>
15
16MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
17MODULE_DESCRIPTION("Xtables: string-based matching");
18MODULE_LICENSE("GPL");
19MODULE_ALIAS("ipt_string");
20MODULE_ALIAS("ip6t_string");
21MODULE_ALIAS("ebt_string");
22
23static bool
24string_mt(const struct sk_buff *skb, struct xt_action_param *par)
25{
26	const struct xt_string_info *conf = par->matchinfo;
27	bool invert;
28
29	invert = conf->u.v1.flags & XT_STRING_FLAG_INVERT;
30
31	return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
32			     conf->to_offset, conf->config)
33			     != UINT_MAX) ^ invert;
34}
35
36#define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m))
37
38static int string_mt_check(const struct xt_mtchk_param *par)
39{
40	struct xt_string_info *conf = par->matchinfo;
41	struct ts_config *ts_conf;
42	int flags = TS_AUTOLOAD;
43
44	/* Damn, can't handle this case properly with iptables... */
45	if (conf->from_offset > conf->to_offset)
46		return -EINVAL;
47	if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')
48		return -EINVAL;
49	if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)
50		return -EINVAL;
51	if (conf->u.v1.flags &
52	    ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT))
53		return -EINVAL;
54	if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE)
55		flags |= TS_IGNORECASE;
56	ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
57				     GFP_KERNEL, flags);
58	if (IS_ERR(ts_conf))
59		return PTR_ERR(ts_conf);
60
61	conf->config = ts_conf;
62	return 0;
63}
64
65static void string_mt_destroy(const struct xt_mtdtor_param *par)
66{
67	textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config);
68}
69
70static struct xt_match xt_string_mt_reg __read_mostly = {
71	.name       = "string",
72	.revision   = 1,
73	.family     = NFPROTO_UNSPEC,
74	.checkentry = string_mt_check,
75	.match      = string_mt,
76	.destroy    = string_mt_destroy,
77	.matchsize  = sizeof(struct xt_string_info),
78	.usersize   = offsetof(struct xt_string_info, config),
79	.me         = THIS_MODULE,
80};
81
82static int __init string_mt_init(void)
83{
84	return xt_register_match(&xt_string_mt_reg);
85}
86
87static void __exit string_mt_exit(void)
88{
89	xt_unregister_match(&xt_string_mt_reg);
90}
91
92module_init(string_mt_init);
93module_exit(string_mt_exit);

 
 1/* String matching match for iptables
 2 *
 3 * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
 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 version 2 as
 7 * published by the Free Software Foundation.
 8 */
 9
10#include <linux/gfp.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/skbuff.h>
15#include <linux/netfilter/x_tables.h>
16#include <linux/netfilter/xt_string.h>
17#include <linux/textsearch.h>
18
19MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
20MODULE_DESCRIPTION("Xtables: string-based matching");
21MODULE_LICENSE("GPL");
22MODULE_ALIAS("ipt_string");
23MODULE_ALIAS("ip6t_string");
24MODULE_ALIAS("ebt_string");
25
26static bool
27string_mt(const struct sk_buff *skb, struct xt_action_param *par)
28{
29	const struct xt_string_info *conf = par->matchinfo;
30	bool invert;
31
32	invert = conf->u.v1.flags & XT_STRING_FLAG_INVERT;
33
34	return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
35			     conf->to_offset, conf->config)
36			     != UINT_MAX) ^ invert;
37}
38
39#define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m))
40
41static int string_mt_check(const struct xt_mtchk_param *par)
42{
43	struct xt_string_info *conf = par->matchinfo;
44	struct ts_config *ts_conf;
45	int flags = TS_AUTOLOAD;
46
47	/* Damn, can't handle this case properly with iptables... */
48	if (conf->from_offset > conf->to_offset)
49		return -EINVAL;
50	if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')
51		return -EINVAL;
52	if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)
53		return -EINVAL;
54	if (conf->u.v1.flags &
55	    ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT))
56		return -EINVAL;
57	if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE)
58		flags |= TS_IGNORECASE;
59	ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
60				     GFP_KERNEL, flags);
61	if (IS_ERR(ts_conf))
62		return PTR_ERR(ts_conf);
63
64	conf->config = ts_conf;
65	return 0;
66}
67
68static void string_mt_destroy(const struct xt_mtdtor_param *par)
69{
70	textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config);
71}
72
73static struct xt_match xt_string_mt_reg __read_mostly = {
74	.name       = "string",
75	.revision   = 1,
76	.family     = NFPROTO_UNSPEC,
77	.checkentry = string_mt_check,
78	.match      = string_mt,
79	.destroy    = string_mt_destroy,
80	.matchsize  = sizeof(struct xt_string_info),
81	.usersize   = offsetof(struct xt_string_info, config),
82	.me         = THIS_MODULE,
83};
84
85static int __init string_mt_init(void)
86{
87	return xt_register_match(&xt_string_mt_reg);
88}
89
90static void __exit string_mt_exit(void)
91{
92	xt_unregister_match(&xt_string_mt_reg);
93}
94
95module_init(string_mt_init);
96module_exit(string_mt_exit);