/* 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/gfp.h>#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("Xtables: string-based matching");MODULE_LICENSE("GPL");MODULE_ALIAS("ipt_string");MODULE_ALIAS("ip6t_string");MODULE_ALIAS("ebt_string"); static boolstring_mt(const struct sk_buff *skb, struct xt_action_param *par){	const struct xt_string_info *conf = par->matchinfo;	bool invert; 	invert = conf->u.v1.flags & XT_STRING_FLAG_INVERT; 	return (skb_find_text((struct sk_buff *)skb, conf->from_offset,			     conf->to_offset, conf->config)			     != UINT_MAX) ^ invert;} #define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m)) static int string_mt_check(const struct xt_mtchk_param *par){	struct xt_string_info *conf = par->matchinfo;	struct ts_config *ts_conf;	int flags = TS_AUTOLOAD; 	/* Damn, can't handle this case properly with iptables... */	if (conf->from_offset > conf->to_offset)		return -EINVAL;	if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')		return -EINVAL;	if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)		return -EINVAL;	if (conf->u.v1.flags &	    ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT))		return -EINVAL;	if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE)		flags |= TS_IGNORECASE;	ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,				     GFP_KERNEL, flags);	if (IS_ERR(ts_conf))		return PTR_ERR(ts_conf); 	conf->config = ts_conf;	return 0;} static void string_mt_destroy(const struct xt_mtdtor_param *par){	textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config);} static struct xt_match xt_string_mt_reg __read_mostly = {	.name       = "string",	.revision   = 1,	.family     = NFPROTO_UNSPEC,	.checkentry = string_mt_check,	.match      = string_mt,	.destroy    = string_mt_destroy,	.matchsize  = sizeof(struct xt_string_info),	.usersize   = offsetof(struct xt_string_info, config),	.me         = THIS_MODULE,}; static int __init string_mt_init(void){	return xt_register_match(&xt_string_mt_reg);} static void __exit string_mt_exit(void){	xt_unregister_match(&xt_string_mt_reg);} module_init(string_mt_init);module_exit(string_mt_exit);