[mirror_ubuntu-bionic-kernel.git] / net / ipv6 / netfilter / ip6t_ah.c

/* Kernel module to match AH parameters. */

/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
 *
 * 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/module.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <linux/types.h>
#include <net/checksum.h>
#include <net/ipv6.h>

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

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IPv6 AH match");
MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

/* Returns 1 if the spi is matched by the range, 0 otherwise */
static inline int
spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
{
	int r=0;
	DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
	       min,spi,max);
	r = (spi >= min && spi <= max) ^ invert;
	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
	return r;
}

static int
match(const struct sk_buff *skb,
      const struct net_device *in,
      const struct net_device *out,
      const void *matchinfo,
      int offset,
      unsigned int protoff,
      int *hotdrop)
{
	struct ip_auth_hdr *ah, _ah;
	const struct ip6t_ah *ahinfo = matchinfo;
	unsigned int ptr;
	unsigned int hdrlen = 0;

	if (ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH) < 0)
		return 0;

	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
	if (ah == NULL) {
		*hotdrop = 1;
		return 0;
	}

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

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

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

/* Called when user tries to insert an entry of this type. */
static int
checkentry(const char *tablename,
          const struct ip6t_ip6 *ip,
          void *matchinfo,
          unsigned int matchinfosize,
          unsigned int hook_mask)
{
	const struct ip6t_ah *ahinfo = matchinfo;

	if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_ah))) {
		DEBUGP("ip6t_ah: matchsize %u != %u\n",
		       matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_ah)));
		return 0;
	}
	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
		DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
		return 0;
	}
	return 1;
}

static struct ip6t_match ah_match = {
	.name		= "ah",
	.match		= &match,
	.checkentry	= &checkentry,
	.me		= THIS_MODULE,
};

static int __init init(void)
{
	return ip6t_register_match(&ah_match);
}

static void __exit cleanup(void)
{
	ip6t_unregister_match(&ah_match);
}

module_init(init);
module_exit(cleanup);
Commit	Line	Data
1da177e4 LT	1	/* Kernel module to match AH parameters. */
	2
	3	/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
	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	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/skbuff.h>
	12	#include <linux/ipv6.h>
	13	#include <linux/types.h>
	14	#include <net/checksum.h>
	15	#include <net/ipv6.h>
	16
	17	#include <linux/netfilter_ipv6/ip6_tables.h>
	18	#include <linux/netfilter_ipv6/ip6t_ah.h>
	19
	20	MODULE_LICENSE("GPL");
	21	MODULE_DESCRIPTION("IPv6 AH match");
	22	MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
	23
	24	#if 0
	25	#define DEBUGP printk
	26	#else
	27	#define DEBUGP(format, args...)
	28	#endif
	29
	30	/* Returns 1 if the spi is matched by the range, 0 otherwise */
	31	static inline int
	32	spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
	33	{
	34	int r=0;
	35	DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
	36	min,spi,max);
	37	r = (spi >= min && spi <= max) ^ invert;
	38	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
	39	return r;
	40	}
	41
	42	static int
	43	match(const struct sk_buff *skb,
	44	const struct net_device *in,
	45	const struct net_device *out,
	46	const void *matchinfo,
	47	int offset,
	48	unsigned int protoff,
	49	int *hotdrop)
	50	{
e674d0f3	51	struct ip_auth_hdr *ah, _ah;
1da177e4	52	const struct ip6t_ah *ahinfo = matchinfo;
1da177e4 LT	53	unsigned int ptr;
	54	unsigned int hdrlen = 0;
	55
e674d0f3	56	if (ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH) < 0)
1da177e4 LT	57	return 0;
1da177e4 LT	58
e674d0f3 YK	59	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
e674d0f3 YK	60	if (ah == NULL) {
1da177e4 LT	61	*hotdrop = 1;
	62	return 0;
	63	}
	64
e674d0f3	65	hdrlen = (ah->hdrlen + 2) << 2;
1da177e4 LT	66
	67	DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
	68	DEBUGP("RES %04X ", ah->reserved);
	69	DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
	70
	71	DEBUGP("IPv6 AH spi %02X ",
	72	(spi_match(ahinfo->spis[0], ahinfo->spis[1],
	73	ntohl(ah->spi),
	74	!!(ahinfo->invflags & IP6T_AH_INV_SPI))));
	75	DEBUGP("len %02X %04X %02X ",
	76	ahinfo->hdrlen, hdrlen,
	77	(!ahinfo->hdrlen \|\|
	78	(ahinfo->hdrlen == hdrlen) ^
	79	!!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	80	DEBUGP("res %02X %04X %02X\n",
	81	ahinfo->hdrres, ah->reserved,
	82	!(ahinfo->hdrres && ah->reserved));
	83
	84	return (ah != NULL)
	85	&&
	86	(spi_match(ahinfo->spis[0], ahinfo->spis[1],
	87	ntohl(ah->spi),
	88	!!(ahinfo->invflags & IP6T_AH_INV_SPI)))
	89	&&
	90	(!ahinfo->hdrlen \|\|
	91	(ahinfo->hdrlen == hdrlen) ^
	92	!!(ahinfo->invflags & IP6T_AH_INV_LEN))
	93	&&
	94	!(ahinfo->hdrres && ah->reserved);
	95	}
	96
	97	/* Called when user tries to insert an entry of this type. */
	98	static int
	99	checkentry(const char *tablename,
	100	const struct ip6t_ip6 *ip,
	101	void *matchinfo,
	102	unsigned int matchinfosize,
	103	unsigned int hook_mask)
	104	{
	105	const struct ip6t_ah *ahinfo = matchinfo;
	106
	107	if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_ah))) {
	108	DEBUGP("ip6t_ah: matchsize %u != %u\n",
	109	matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_ah)));
	110	return 0;
	111	}
	112	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
	113	DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
	114	return 0;
	115	}
	116	return 1;
	117	}
	118
	119	static struct ip6t_match ah_match = {
	120	.name = "ah",
	121	.match = &match,
	122	.checkentry = &checkentry,
	123	.me = THIS_MODULE,
	124	};
	125
	126	static int __init init(void)
	127	{
	128	return ip6t_register_match(&ah_match);
	129	}
130
131	static void __exit cleanup(void)
132	{
133	ip6t_unregister_match(&ah_match);
134	}
135
136	module_init(init);
137	module_exit(cleanup);