diff options
| -rw-r--r-- | include/linux/netfilter_ipv4/ipt_string.h | 18 | ||||
| -rw-r--r-- | net/ipv4/netfilter/Kconfig | 12 | ||||
| -rw-r--r-- | net/ipv4/netfilter/Makefile | 1 | ||||
| -rw-r--r-- | net/ipv4/netfilter/ipt_string.c | 91 |
4 files changed, 122 insertions, 0 deletions
diff --git a/include/linux/netfilter_ipv4/ipt_string.h b/include/linux/netfilter_ipv4/ipt_string.h new file mode 100644 index 0000000..a265f6e --- /dev/null +++ b/include/linux/netfilter_ipv4/ipt_string.h @@ -0,0 +1,18 @@ +#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*/ diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig index 3f7e6e4..f2bea6e 100644 --- a/net/ipv4/netfilter/Kconfig +++ b/net/ipv4/netfilter/Kconfig @@ -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" diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile index 7c8ae85..89cae69 100644 --- a/net/ipv4/netfilter/Makefile +++ b/net/ipv4/netfilter/Makefile @@ -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 diff --git a/net/ipv4/netfilter/ipt_string.c b/net/ipv4/netfilter/ipt_string.c new file mode 100644 index 0000000..b5def20 --- /dev/null +++ b/net/ipv4/netfilter/ipt_string.c @@ -0,0 +1,91 @@ +/* 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); |