Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 1 | /* String matching match for iptables |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 2 | * |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 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> |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 14 | #include <linux/netfilter/x_tables.h> |
| 15 | #include <linux/netfilter/xt_string.h> |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 16 | #include <linux/textsearch.h> |
| 17 | |
| 18 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 19 | MODULE_DESCRIPTION("Xtables: string-based matching"); |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 20 | MODULE_LICENSE("GPL"); |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 21 | MODULE_ALIAS("ipt_string"); |
| 22 | MODULE_ALIAS("ip6t_string"); |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 23 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 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) |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 29 | { |
Patrick McHardy | 3e72b2f | 2006-05-29 18:19:19 -0700 | [diff] [blame] | 30 | const struct xt_string_info *conf = matchinfo; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 31 | struct ts_state state; |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 32 | int invert; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 33 | |
| 34 | memset(&state, 0, sizeof(struct ts_state)); |
| 35 | |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 36 | invert = (match->revision == 0 ? conf->u.v0.invert : |
| 37 | conf->u.v1.flags & XT_STRING_FLAG_INVERT); |
| 38 | |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 39 | return (skb_find_text((struct sk_buff *)skb, conf->from_offset, |
| 40 | conf->to_offset, conf->config, &state) |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 41 | != UINT_MAX) ^ invert; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 42 | } |
| 43 | |
Jan Engelhardt | e79ec50 | 2007-12-17 22:44:06 -0800 | [diff] [blame] | 44 | #define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m)) |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 45 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 46 | static bool |
| 47 | string_mt_check(const char *tablename, const void *ip, |
| 48 | const struct xt_match *match, void *matchinfo, |
| 49 | unsigned int hook_mask) |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 50 | { |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 51 | struct xt_string_info *conf = matchinfo; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 52 | struct ts_config *ts_conf; |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 53 | int flags = TS_AUTOLOAD; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 54 | |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 55 | /* Damn, can't handle this case properly with iptables... */ |
| 56 | if (conf->from_offset > conf->to_offset) |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 57 | return false; |
Patrick McHardy | 3ab7208 | 2006-07-31 23:47:31 -0700 | [diff] [blame] | 58 | if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0') |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 59 | return false; |
Patrick McHardy | 3ab7208 | 2006-07-31 23:47:31 -0700 | [diff] [blame] | 60 | if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE) |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 61 | return false; |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 62 | if (match->revision == 1) { |
| 63 | if (conf->u.v1.flags & |
| 64 | ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT)) |
| 65 | return false; |
| 66 | if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE) |
| 67 | flags |= TS_IGNORECASE; |
| 68 | } |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 69 | ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen, |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 70 | GFP_KERNEL, flags); |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 71 | if (IS_ERR(ts_conf)) |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 72 | return false; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 73 | |
| 74 | conf->config = ts_conf; |
| 75 | |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 76 | return true; |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 77 | } |
| 78 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 79 | static void string_mt_destroy(const struct xt_match *match, void *matchinfo) |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 80 | { |
| 81 | textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config); |
| 82 | } |
| 83 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 84 | static struct xt_match string_mt_reg[] __read_mostly = { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 85 | { |
| 86 | .name = "string", |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 87 | .revision = 0, |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 88 | .family = AF_INET, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 89 | .checkentry = string_mt_check, |
| 90 | .match = string_mt, |
| 91 | .destroy = string_mt_destroy, |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 92 | .matchsize = sizeof(struct xt_string_info), |
| 93 | .me = THIS_MODULE |
| 94 | }, |
| 95 | { |
| 96 | .name = "string", |
Joonwoo Park | 4ad3f26 | 2008-07-08 02:38:56 -0700 | [diff] [blame] | 97 | .revision = 1, |
| 98 | .family = AF_INET, |
| 99 | .checkentry = string_mt_check, |
| 100 | .match = string_mt, |
| 101 | .destroy = string_mt_destroy, |
| 102 | .matchsize = sizeof(struct xt_string_info), |
| 103 | .me = THIS_MODULE |
| 104 | }, |
| 105 | { |
| 106 | .name = "string", |
| 107 | .revision = 0, |
| 108 | .family = AF_INET6, |
| 109 | .checkentry = string_mt_check, |
| 110 | .match = string_mt, |
| 111 | .destroy = string_mt_destroy, |
| 112 | .matchsize = sizeof(struct xt_string_info), |
| 113 | .me = THIS_MODULE |
| 114 | }, |
| 115 | { |
| 116 | .name = "string", |
| 117 | .revision = 1, |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 118 | .family = AF_INET6, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 119 | .checkentry = string_mt_check, |
| 120 | .match = string_mt, |
| 121 | .destroy = string_mt_destroy, |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 122 | .matchsize = sizeof(struct xt_string_info), |
| 123 | .me = THIS_MODULE |
| 124 | }, |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 125 | }; |
| 126 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 127 | static int __init string_mt_init(void) |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 128 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 129 | return xt_register_matches(string_mt_reg, ARRAY_SIZE(string_mt_reg)); |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 130 | } |
| 131 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 132 | static void __exit string_mt_exit(void) |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 133 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 134 | xt_unregister_matches(string_mt_reg, ARRAY_SIZE(string_mt_reg)); |
Pablo Neira Ayuso | 7567662 | 2005-08-21 23:30:34 -0700 | [diff] [blame] | 135 | } |
| 136 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 137 | module_init(string_mt_init); |
| 138 | module_exit(string_mt_exit); |