[linux.git] / net / ipv6 / netfilter / ip6t_ah.c

/* Kernel module to match AH parameters. */

/* (C) 2001-2002 Andras Kis-Szabo <[email protected]>
 *
 * 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.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/types.h>
#include <net/checksum.h>
#include <net/ipv6.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_ipv6/ip6t_ah.h>

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Xtables: IPv6 IPsec-AH match");
MODULE_AUTHOR("Andras Kis-Szabo <[email protected]>");

/* Returns 1 if the spi is matched by the range, 0 otherwise */
static inline bool
spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
{
	bool r;

	pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n",
		 invert ? '!' : ' ', min, spi, max);
	r = (spi >= min && spi <= max) ^ invert;
	pr_debug(" result %s\n", r ? "PASS" : "FAILED");
	return r;
}

static bool ah_mt6(const struct sk_buff *skb, struct xt_action_param *par)
{
	struct ip_auth_hdr _ah;
	const struct ip_auth_hdr *ah;
	const struct ip6t_ah *ahinfo = par->matchinfo;
	unsigned int ptr;
	unsigned int hdrlen = 0;
	int err;

	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
	if (err < 0) {
		if (err != -ENOENT)
			par->hotdrop = true;
		return false;
	}

	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
	if (ah == NULL) {
		par->hotdrop = true;
		return false;
	}

	hdrlen = (ah->hdrlen + 2) << 2;

	pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
	pr_debug("RES %04X ", ah->reserved);
	pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));

	pr_debug("IPv6 AH spi %02X ",
		 spi_match(ahinfo->spis[0], ahinfo->spis[1],
			   ntohl(ah->spi),
			   !!(ahinfo->invflags & IP6T_AH_INV_SPI)));
	pr_debug("len %02X %04X %02X ",
		 ahinfo->hdrlen, hdrlen,
		 (!ahinfo->hdrlen ||
		  (ahinfo->hdrlen == hdrlen) ^
		  !!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	pr_debug("res %02X %04X %02X\n",
		 ahinfo->hdrres, ah->reserved,
		 !(ahinfo->hdrres && ah->reserved));

	return (ah != NULL) &&
		spi_match(ahinfo->spis[0], ahinfo->spis[1],
			  ntohl(ah->spi),
			  !!(ahinfo->invflags & IP6T_AH_INV_SPI)) &&
		(!ahinfo->hdrlen ||
		 (ahinfo->hdrlen == hdrlen) ^
		 !!(ahinfo->invflags & IP6T_AH_INV_LEN)) &&
		!(ahinfo->hdrres && ah->reserved);
}

static int ah_mt6_check(const struct xt_mtchk_param *par)
{
	const struct ip6t_ah *ahinfo = par->matchinfo;

	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
		pr_debug("unknown flags %X\n", ahinfo->invflags);
		return -EINVAL;
	}
	return 0;
}

static struct xt_match ah_mt6_reg __read_mostly = {
	.name		= "ah",
	.family		= NFPROTO_IPV6,
	.match		= ah_mt6,
	.matchsize	= sizeof(struct ip6t_ah),
	.checkentry	= ah_mt6_check,
	.me		= THIS_MODULE,
};

static int __init ah_mt6_init(void)
{
	return xt_register_match(&ah_mt6_reg);
}

static void __exit ah_mt6_exit(void)
{
	xt_unregister_match(&ah_mt6_reg);
}

module_init(ah_mt6_init);
module_exit(ah_mt6_exit);
Commit	Line	Data
1da177e4 LT	1	/* Kernel module to match AH parameters. */
	2
	3	/* (C) 2001-2002 Andras Kis-Szabo <[email protected]>
	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	*/
ff67e4e4	9	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
1da177e4 LT	10	#include <linux/module.h>
1da177e4 LT	11	#include <linux/skbuff.h>
14c85021	12	#include <linux/ip.h>
1da177e4 LT	13	#include <linux/ipv6.h>
	14	#include <linux/types.h>
	15	#include <net/checksum.h>
	16	#include <net/ipv6.h>
	17
6709dbbb	18	#include <linux/netfilter/x_tables.h>
1da177e4 LT	19	#include <linux/netfilter_ipv6/ip6_tables.h>
	20	#include <linux/netfilter_ipv6/ip6t_ah.h>
	21
	22	MODULE_LICENSE("GPL");
2ae15b64	23	MODULE_DESCRIPTION("Xtables: IPv6 IPsec-AH match");
1da177e4 LT	24	MODULE_AUTHOR("Andras Kis-Szabo <[email protected]>");
1da177e4 LT	25
1da177e4	26	/* Returns 1 if the spi is matched by the range, 0 otherwise */
1d93a9cb JE	27	static inline bool
1d93a9cb JE	28	spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
1da177e4	29	{
1d93a9cb	30	bool r;
0d53778e	31
ff67e4e4	32	pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n",
0d53778e	33	invert ? '!' : ' ', min, spi, max);
1da177e4	34	r = (spi >= min && spi <= max) ^ invert;
0d53778e	35	pr_debug(" result %s\n", r ? "PASS" : "FAILED");
1da177e4 LT	36	return r;
	37	}
	38
62fc8051	39	static bool ah_mt6(const struct sk_buff skb, struct xt_action_param par)
1da177e4	40	{
a47362a2 JE	41	struct ip_auth_hdr _ah;
a47362a2 JE	42	const struct ip_auth_hdr *ah;
f7108a20	43	const struct ip6t_ah *ahinfo = par->matchinfo;
1da177e4 LT	44	unsigned int ptr;
1da177e4 LT	45	unsigned int hdrlen = 0;
6d381634	46	int err;
1da177e4	47
6d381634 PM	48	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
	49	if (err < 0) {
	50	if (err != -ENOENT)
b4ba2611	51	par->hotdrop = true;
1d93a9cb	52	return false;
6d381634	53	}
1da177e4	54
e674d0f3 YK	55	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
e674d0f3 YK	56	if (ah == NULL) {
b4ba2611	57	par->hotdrop = true;
1d93a9cb	58	return false;
1da177e4 LT	59	}
1da177e4 LT	60
e674d0f3	61	hdrlen = (ah->hdrlen + 2) << 2;
1da177e4	62
0d53778e PM	63	pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
	64	pr_debug("RES %04X ", ah->reserved);
	65	pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
	66
	67	pr_debug("IPv6 AH spi %02X ",
	68	spi_match(ahinfo->spis[0], ahinfo->spis[1],
	69	ntohl(ah->spi),
	70	!!(ahinfo->invflags & IP6T_AH_INV_SPI)));
	71	pr_debug("len %02X %04X %02X ",
	72	ahinfo->hdrlen, hdrlen,
	73	(!ahinfo->hdrlen \|\|
	74	(ahinfo->hdrlen == hdrlen) ^
	75	!!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	76	pr_debug("res %02X %04X %02X\n",
	77	ahinfo->hdrres, ah->reserved,
	78	!(ahinfo->hdrres && ah->reserved));
1da177e4	79
3666ed1c JP	80	return (ah != NULL) &&
	81	spi_match(ahinfo->spis[0], ahinfo->spis[1],
	82	ntohl(ah->spi),
	83	!!(ahinfo->invflags & IP6T_AH_INV_SPI)) &&
	84	(!ahinfo->hdrlen \|\|
	85	(ahinfo->hdrlen == hdrlen) ^
	86	!!(ahinfo->invflags & IP6T_AH_INV_LEN)) &&
	87	!(ahinfo->hdrres && ah->reserved);
1da177e4 LT	88	}
1da177e4 LT	89
b0f38452	90	static int ah_mt6_check(const struct xt_mtchk_param *par)
1da177e4	91	{
9b4fce7a	92	const struct ip6t_ah *ahinfo = par->matchinfo;
1da177e4	93
1da177e4	94	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
ff67e4e4	95	pr_debug("unknown flags %X\n", ahinfo->invflags);
bd414ee6	96	return -EINVAL;
1da177e4	97	}
bd414ee6	98	return 0;
1da177e4 LT	99	}
1da177e4 LT	100
d3c5ee6d	101	static struct xt_match ah_mt6_reg __read_mostly = {
1da177e4	102	.name = "ah",
ee999d8b	103	.family = NFPROTO_IPV6,
d3c5ee6d	104	.match = ah_mt6,
7f939713	105	.matchsize = sizeof(struct ip6t_ah),
d3c5ee6d	106	.checkentry = ah_mt6_check,
1da177e4 LT	107	.me = THIS_MODULE,
	108	};
	109
d3c5ee6d	110	static int __init ah_mt6_init(void)
1da177e4	111	{
d3c5ee6d	112	return xt_register_match(&ah_mt6_reg);
1da177e4 LT	113	}
1da177e4 LT	114
d3c5ee6d	115	static void __exit ah_mt6_exit(void)
1da177e4	116	{
d3c5ee6d	117	xt_unregister_match(&ah_mt6_reg);
1da177e4 LT	118	}
1da177e4 LT	119
d3c5ee6d JE	120	module_init(ah_mt6_init);
d3c5ee6d JE	121	module_exit(ah_mt6_exit);