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 |
62fc8051 | 26 | string_mt(const struct sk_buff *skb, struct xt_action_param *par) |
7567662b | 27 | { |
f7108a20 | 28 | const struct xt_string_info *conf = par->matchinfo; |
d879e19e | 29 | bool invert; |
7567662b | 30 | |
d879e19e | 31 | invert = conf->u.v1.flags & XT_STRING_FLAG_INVERT; |
4ad3f261 | 32 | |
601e68e1 | 33 | return (skb_find_text((struct sk_buff *)skb, conf->from_offset, |
059a2440 | 34 | conf->to_offset, conf->config) |
4ad3f261 | 35 | != UINT_MAX) ^ invert; |
7567662b PNA |
36 | } |
37 | ||
e79ec50b | 38 | #define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m)) |
7567662b | 39 | |
b0f38452 | 40 | static int string_mt_check(const struct xt_mtchk_param *par) |
7567662b | 41 | { |
9b4fce7a | 42 | struct xt_string_info *conf = par->matchinfo; |
7567662b | 43 | struct ts_config *ts_conf; |
4ad3f261 | 44 | int flags = TS_AUTOLOAD; |
7567662b | 45 | |
7567662b PNA |
46 | /* Damn, can't handle this case properly with iptables... */ |
47 | if (conf->from_offset > conf->to_offset) | |
bd414ee6 | 48 | return -EINVAL; |
3ab72088 | 49 | if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0') |
bd414ee6 | 50 | return -EINVAL; |
3ab72088 | 51 | if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE) |
bd414ee6 | 52 | return -EINVAL; |
d879e19e JE |
53 | if (conf->u.v1.flags & |
54 | ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT)) | |
55 | return -EINVAL; | |
56 | if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE) | |
57 | flags |= TS_IGNORECASE; | |
7567662b | 58 | ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen, |
4ad3f261 | 59 | GFP_KERNEL, flags); |
7567662b | 60 | if (IS_ERR(ts_conf)) |
4a5a5c73 | 61 | return PTR_ERR(ts_conf); |
7567662b PNA |
62 | |
63 | conf->config = ts_conf; | |
bd414ee6 | 64 | return 0; |
7567662b PNA |
65 | } |
66 | ||
6be3d859 | 67 | static void string_mt_destroy(const struct xt_mtdtor_param *par) |
7567662b | 68 | { |
6be3d859 | 69 | textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config); |
7567662b PNA |
70 | } |
71 | ||
d879e19e JE |
72 | static struct xt_match xt_string_mt_reg __read_mostly = { |
73 | .name = "string", | |
74 | .revision = 1, | |
75 | .family = NFPROTO_UNSPEC, | |
76 | .checkentry = string_mt_check, | |
77 | .match = string_mt, | |
78 | .destroy = string_mt_destroy, | |
79 | .matchsize = sizeof(struct xt_string_info), | |
80 | .me = THIS_MODULE, | |
7567662b PNA |
81 | }; |
82 | ||
d3c5ee6d | 83 | static int __init string_mt_init(void) |
7567662b | 84 | { |
d879e19e | 85 | return xt_register_match(&xt_string_mt_reg); |
7567662b PNA |
86 | } |
87 | ||
d3c5ee6d | 88 | static void __exit string_mt_exit(void) |
7567662b | 89 | { |
d879e19e | 90 | xt_unregister_match(&xt_string_mt_reg); |
7567662b PNA |
91 | } |
92 | ||
d3c5ee6d JE |
93 | module_init(string_mt_init); |
94 | module_exit(string_mt_exit); |