]>
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 | ||
5a0e3ad6 | 10 | #include <linux/gfp.h> |
7567662b PNA |
11 | #include <linux/init.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/skbuff.h> | |
2e4e6a17 HW |
15 | #include <linux/netfilter/x_tables.h> |
16 | #include <linux/netfilter/xt_string.h> | |
7567662b PNA |
17 | #include <linux/textsearch.h> |
18 | ||
19 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>"); | |
2ae15b64 | 20 | MODULE_DESCRIPTION("Xtables: string-based matching"); |
7567662b | 21 | MODULE_LICENSE("GPL"); |
2e4e6a17 HW |
22 | MODULE_ALIAS("ipt_string"); |
23 | MODULE_ALIAS("ip6t_string"); | |
7567662b | 24 | |
d3c5ee6d | 25 | static bool |
f7108a20 | 26 | string_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
7567662b | 27 | { |
f7108a20 | 28 | const struct xt_string_info *conf = par->matchinfo; |
7567662b | 29 | struct ts_state state; |
4ad3f261 | 30 | int invert; |
7567662b PNA |
31 | |
32 | memset(&state, 0, sizeof(struct ts_state)); | |
33 | ||
f7108a20 | 34 | invert = (par->match->revision == 0 ? conf->u.v0.invert : |
4ad3f261 JP |
35 | conf->u.v1.flags & XT_STRING_FLAG_INVERT); |
36 | ||
601e68e1 YH |
37 | return (skb_find_text((struct sk_buff *)skb, conf->from_offset, |
38 | conf->to_offset, conf->config, &state) | |
4ad3f261 | 39 | != UINT_MAX) ^ invert; |
7567662b PNA |
40 | } |
41 | ||
e79ec50b | 42 | #define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m)) |
7567662b | 43 | |
9b4fce7a | 44 | static bool string_mt_check(const struct xt_mtchk_param *par) |
7567662b | 45 | { |
9b4fce7a | 46 | struct xt_string_info *conf = par->matchinfo; |
7567662b | 47 | struct ts_config *ts_conf; |
4ad3f261 | 48 | int flags = TS_AUTOLOAD; |
7567662b | 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; |
9b4fce7a | 57 | if (par->match->revision == 1) { |
4ad3f261 JP |
58 | if (conf->u.v1.flags & |
59 | ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT)) | |
60 | return false; | |
61 | if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE) | |
62 | flags |= TS_IGNORECASE; | |
63 | } | |
7567662b | 64 | ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen, |
4ad3f261 | 65 | GFP_KERNEL, flags); |
7567662b | 66 | if (IS_ERR(ts_conf)) |
ccb79bdc | 67 | return false; |
7567662b PNA |
68 | |
69 | conf->config = ts_conf; | |
70 | ||
ccb79bdc | 71 | return true; |
7567662b PNA |
72 | } |
73 | ||
6be3d859 | 74 | static void string_mt_destroy(const struct xt_mtdtor_param *par) |
7567662b | 75 | { |
6be3d859 | 76 | textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config); |
7567662b PNA |
77 | } |
78 | ||
55b69e91 | 79 | static struct xt_match xt_string_mt_reg[] __read_mostly = { |
4470bbc7 PM |
80 | { |
81 | .name = "string", | |
4ad3f261 | 82 | .revision = 0, |
55b69e91 | 83 | .family = NFPROTO_UNSPEC, |
4ad3f261 JP |
84 | .checkentry = string_mt_check, |
85 | .match = string_mt, | |
86 | .destroy = string_mt_destroy, | |
87 | .matchsize = sizeof(struct xt_string_info), | |
88 | .me = THIS_MODULE | |
89 | }, | |
90 | { | |
91 | .name = "string", | |
92 | .revision = 1, | |
55b69e91 | 93 | .family = NFPROTO_UNSPEC, |
d3c5ee6d JE |
94 | .checkentry = string_mt_check, |
95 | .match = string_mt, | |
96 | .destroy = string_mt_destroy, | |
4470bbc7 PM |
97 | .matchsize = sizeof(struct xt_string_info), |
98 | .me = THIS_MODULE | |
99 | }, | |
7567662b PNA |
100 | }; |
101 | ||
d3c5ee6d | 102 | static int __init string_mt_init(void) |
7567662b | 103 | { |
55b69e91 JE |
104 | return xt_register_matches(xt_string_mt_reg, |
105 | ARRAY_SIZE(xt_string_mt_reg)); | |
7567662b PNA |
106 | } |
107 | ||
d3c5ee6d | 108 | static void __exit string_mt_exit(void) |
7567662b | 109 | { |
55b69e91 | 110 | xt_unregister_matches(xt_string_mt_reg, ARRAY_SIZE(xt_string_mt_reg)); |
7567662b PNA |
111 | } |
112 | ||
d3c5ee6d JE |
113 | module_init(string_mt_init); |
114 | module_exit(string_mt_exit); |