1 files changed, 113 insertions, 0 deletions
diff --git a/net/netfilter/xt_string.c b/net/netfilter/xt_string.c
new file mode 100644
index 0000000..b4d7741
--- /dev/null
+++ b/net/netfilter/xt_string.c
@@ -0,0 +1,113 @@
+/* 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/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");
+
+static bool
+string_mt(const struct sk_buff *skb, const struct xt_match_param *par)
+{
+	const struct xt_string_info *conf = par->matchinfo;
+	struct ts_state state;
+	int invert;
+
+	memset(&state, 0, sizeof(struct ts_state));
+
+	invert = (par->match->revision == 0 ? conf->u.v0.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, &state)
+			     != UINT_MAX) ^ invert;
+}
+
+#define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m))
+
+static bool 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 false;
+	if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')
+		return false;
+	if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)
+		return false;
+	if (par->match->revision == 1) {
+		if (conf->u.v1.flags &
+		    ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT))
+			return false;
+		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 false;
+
+	conf->config = ts_conf;
+
+	return true;
+}
+
+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	= 0,
+		.family		= NFPROTO_UNSPEC,
+		.checkentry	= string_mt_check,
+		.match 		= string_mt,
+		.destroy 	= string_mt_destroy,
+		.matchsize	= sizeof(struct xt_string_info),
+		.me 		= THIS_MODULE
+	},
+	{
+		.name 		= "string",
+		.revision	= 1,
+		.family		= NFPROTO_UNSPEC,
+		.checkentry	= string_mt_check,
+		.match 		= string_mt,
+		.destroy 	= string_mt_destroy,
+		.matchsize	= sizeof(struct xt_string_info),
+		.me 		= THIS_MODULE
+	},
+};
+
+static int __init string_mt_init(void)
+{
+	return xt_register_matches(xt_string_mt_reg,
+				   ARRAY_SIZE(xt_string_mt_reg));
+}
+
+static void __exit string_mt_exit(void)
+{
+	xt_unregister_matches(xt_string_mt_reg, ARRAY_SIZE(xt_string_mt_reg));
+}
+
+module_init(string_mt_init);
+module_exit(string_mt_exit);