Commit 7567662b authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso Committed by David S. Miller
Browse files

[NETFILTER]: Add string match


Signed-off-by: default avatarPablo Neira Ayuso <pablo@eurodev.net>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 24117727
#ifndef _IPT_STRING_H
#define _IPT_STRING_H
#define IPT_STRING_MAX_PATTERN_SIZE 128
#define IPT_STRING_MAX_ALGO_NAME_SIZE 16
struct ipt_string_info
{
u_int16_t from_offset;
u_int16_t to_offset;
char algo[IPT_STRING_MAX_ALGO_NAME_SIZE];
char pattern[IPT_STRING_MAX_PATTERN_SIZE];
u_int8_t patlen;
u_int8_t invert;
struct ts_config __attribute__((aligned(8))) *config;
};
#endif /*_IPT_STRING_H*/
......@@ -410,6 +410,18 @@ config IP_NF_MATCH_HASHLIMIT
destination IP' or `500pps from any given source IP' with a single
IPtables rule.
config IP_NF_MATCH_STRING
tristate 'string match support'
depends on IP_NF_IPTABLES
select TEXTSEARCH
select TEXTSEARCH_KMP
select TEXTSEARCH_FSM
help
This option adds a `string' match, which allows you to look for
pattern matchings in packets.
To compile it as a module, choose M here. If unsure, say N.
# `filter', generic and specific targets
config IP_NF_FILTER
tristate "Packet filtering"
......
......@@ -65,6 +65,7 @@ obj-$(CONFIG_IP_NF_MATCH_REALM) += ipt_realm.o
obj-$(CONFIG_IP_NF_MATCH_ADDRTYPE) += ipt_addrtype.o
obj-$(CONFIG_IP_NF_MATCH_PHYSDEV) += ipt_physdev.o
obj-$(CONFIG_IP_NF_MATCH_COMMENT) += ipt_comment.o
obj-$(CONFIG_IP_NF_MATCH_STRING) += ipt_string.o
# targets
obj-$(CONFIG_IP_NF_TARGET_REJECT) += ipt_REJECT.o
......
/* 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_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_string.h>
#include <linux/textsearch.h>
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
MODULE_DESCRIPTION("IP tables string match module");
MODULE_LICENSE("GPL");
static int match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
int *hotdrop)
{
struct ts_state state;
struct ipt_string_info *conf = (struct ipt_string_info *) matchinfo;
memset(&state, 0, sizeof(struct ts_state));
return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
conf->to_offset, conf->config, &state)
!= UINT_MAX) && !conf->invert;
}
#define STRING_TEXT_PRIV(m) ((struct ipt_string_info *) m)
static int checkentry(const char *tablename,
const struct ipt_ip *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
struct ipt_string_info *conf = matchinfo;
struct ts_config *ts_conf;
if (matchsize != IPT_ALIGN(sizeof(struct ipt_string_info)))
return 0;
/* Damn, can't handle this case properly with iptables... */
if (conf->from_offset > conf->to_offset)
return 0;
ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
GFP_KERNEL, TS_AUTOLOAD);
if (IS_ERR(ts_conf))
return 0;
conf->config = ts_conf;
return 1;
}
static void destroy(void *matchinfo, unsigned int matchsize)
{
textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);
}
static struct ipt_match string_match = {
.name = "string",
.match = match,
.checkentry = checkentry,
.destroy = destroy,
.me = THIS_MODULE
};
static int __init init(void)
{
return ipt_register_match(&string_match);
}
static void __exit fini(void)
{
ipt_unregister_match(&string_match);
}
module_init(init);
module_exit(fini);
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