Commit | Line | Data |
---|---|---|
7567662b | 1 | /* String matching match for iptables |
601e68e1 | 2 | * |
7567662b PNA |
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/init.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/skbuff.h> | |
2e4e6a17 HW |
14 | #include <linux/netfilter/x_tables.h> |
15 | #include <linux/netfilter/xt_string.h> | |
7567662b PNA |
16 | #include <linux/textsearch.h> |
17 | ||
18 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>"); | |
2ae15b64 | 19 | MODULE_DESCRIPTION("Xtables: string-based matching"); |
7567662b | 20 | MODULE_LICENSE("GPL"); |
2e4e6a17 HW |
21 | MODULE_ALIAS("ipt_string"); |
22 | MODULE_ALIAS("ip6t_string"); | |
7567662b | 23 | |
d3c5ee6d JE |
24 | static bool |
25 | string_mt(const struct sk_buff *skb, const struct net_device *in, | |
26 | const struct net_device *out, const struct xt_match *match, | |
27 | const void *matchinfo, int offset, unsigned int protoff, | |
28 | bool *hotdrop) | |
7567662b | 29 | { |
3e72b2fe | 30 | const struct xt_string_info *conf = matchinfo; |
7567662b | 31 | struct ts_state state; |
7567662b PNA |
32 | |
33 | memset(&state, 0, sizeof(struct ts_state)); | |
34 | ||
601e68e1 YH |
35 | return (skb_find_text((struct sk_buff *)skb, conf->from_offset, |
36 | conf->to_offset, conf->config, &state) | |
97c802a1 | 37 | != UINT_MAX) ^ conf->invert; |
7567662b PNA |
38 | } |
39 | ||
e79ec50b | 40 | #define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m)) |
7567662b | 41 | |
d3c5ee6d JE |
42 | static bool |
43 | string_mt_check(const char *tablename, const void *ip, | |
44 | const struct xt_match *match, void *matchinfo, | |
45 | unsigned int hook_mask) | |
7567662b | 46 | { |
2e4e6a17 | 47 | struct xt_string_info *conf = matchinfo; |
7567662b PNA |
48 | struct ts_config *ts_conf; |
49 | ||
7567662b PNA |
50 | /* Damn, can't handle this case properly with iptables... */ |
51 | if (conf->from_offset > conf->to_offset) | |
ccb79bdc | 52 | return false; |
3ab72088 | 53 | if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0') |
ccb79bdc | 54 | return false; |
3ab72088 | 55 | if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE) |
ccb79bdc | 56 | return false; |
7567662b PNA |
57 | ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen, |
58 | GFP_KERNEL, TS_AUTOLOAD); | |
59 | if (IS_ERR(ts_conf)) | |
ccb79bdc | 60 | return false; |
7567662b PNA |
61 | |
62 | conf->config = ts_conf; | |
63 | ||
ccb79bdc | 64 | return true; |
7567662b PNA |
65 | } |
66 | ||
d3c5ee6d | 67 | static void string_mt_destroy(const struct xt_match *match, void *matchinfo) |
7567662b PNA |
68 | { |
69 | textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config); | |
70 | } | |
71 | ||
d3c5ee6d | 72 | static struct xt_match string_mt_reg[] __read_mostly = { |
4470bbc7 PM |
73 | { |
74 | .name = "string", | |
75 | .family = AF_INET, | |
d3c5ee6d JE |
76 | .checkentry = string_mt_check, |
77 | .match = string_mt, | |
78 | .destroy = string_mt_destroy, | |
4470bbc7 PM |
79 | .matchsize = sizeof(struct xt_string_info), |
80 | .me = THIS_MODULE | |
81 | }, | |
82 | { | |
83 | .name = "string", | |
84 | .family = AF_INET6, | |
d3c5ee6d JE |
85 | .checkentry = string_mt_check, |
86 | .match = string_mt, | |
87 | .destroy = string_mt_destroy, | |
4470bbc7 PM |
88 | .matchsize = sizeof(struct xt_string_info), |
89 | .me = THIS_MODULE | |
90 | }, | |
7567662b PNA |
91 | }; |
92 | ||
d3c5ee6d | 93 | static int __init string_mt_init(void) |
7567662b | 94 | { |
d3c5ee6d | 95 | return xt_register_matches(string_mt_reg, ARRAY_SIZE(string_mt_reg)); |
7567662b PNA |
96 | } |
97 | ||
d3c5ee6d | 98 | static void __exit string_mt_exit(void) |
7567662b | 99 | { |
d3c5ee6d | 100 | xt_unregister_matches(string_mt_reg, ARRAY_SIZE(string_mt_reg)); |
7567662b PNA |
101 | } |
102 | ||
d3c5ee6d JE |
103 | module_init(string_mt_init); |
104 | module_exit(string_mt_exit); |