1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/* String matching match for iptables
*
* (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_string.h>
#include <linux/textsearch.h>
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
MODULE_DESCRIPTION("IP tables string match module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_string");
MODULE_ALIAS("ip6t_string");
static int match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
struct ts_state state;
struct xt_string_info *conf = (struct xt_string_info *) matchinfo;
memset(&state, 0, sizeof(struct ts_state));
return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
conf->to_offset, conf->config, &state)
!= UINT_MAX) && !conf->invert;
}
#define STRING_TEXT_PRIV(m) ((struct xt_string_info *) m)
static int checkentry(const char *tablename,
const void *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
struct xt_string_info *conf = matchinfo;
struct ts_config *ts_conf;
if (matchsize != XT_ALIGN(sizeof(struct xt_string_info)))
return 0;
/* Damn, can't handle this case properly with iptables... */
if (conf->from_offset > conf->to_offset)
return 0;
ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
GFP_KERNEL, TS_AUTOLOAD);
if (IS_ERR(ts_conf))
return 0;
conf->config = ts_conf;
return 1;
}
static void destroy(void *matchinfo, unsigned int matchsize)
{
textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);
}
static struct xt_match string_match = {
.name = "string",
.match = match,
.checkentry = checkentry,
.destroy = destroy,
.me = THIS_MODULE
};
static struct xt_match string6_match = {
.name = "string",
.match = match,
.checkentry = checkentry,
.destroy = destroy,
.me = THIS_MODULE
};
static int __init init(void)
{
int ret;
ret = xt_register_match(AF_INET, &string_match);
if (ret)
return ret;
ret = xt_register_match(AF_INET6, &string6_match);
if (ret)
xt_unregister_match(AF_INET, &string_match);
return ret;
}
static void __exit fini(void)
{
xt_unregister_match(AF_INET, &string_match);
xt_unregister_match(AF_INET6, &string6_match);
}
module_init(init);
module_exit(fini);
|
