[linux.git] / net / ipv6 / ah6.c

/*
 * Copyright (C)2002 USAGI/WIDE Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Authors
 *
 *	Mitsuru KANDA @USAGI       : IPv6 Support
 * 	Kazunori MIYAZAWA @USAGI   :
 * 	Kunihiro Ishiguro <[email protected]>
 *
 * 	This file is derived from net/ipv4/ah.c.
 */

#include <linux/module.h>
#include <net/ip.h>
#include <net/ah.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <linux/string.h>
#include <net/icmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <asm/scatterlist.h>

static int zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
{
	u8 *opt = (u8 *)opthdr;
	int len = ipv6_optlen(opthdr);
	int off = 0;
	int optlen = 0;

	off += 2;
	len -= 2;

	while (len > 0) {

		switch (opt[off]) {

		case IPV6_TLV_PAD0:
			optlen = 1;
			break;
		default:
			if (len < 2)
				goto bad;
			optlen = opt[off+1]+2;
			if (len < optlen)
				goto bad;
			if (opt[off] & 0x20)
				memset(&opt[off+2], 0, opt[off+1]);
			break;
		}

		off += optlen;
		len -= optlen;
	}
	if (len == 0)
		return 1;

bad:
	return 0;
}

#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
/**
 *	ipv6_rearrange_destopt - rearrange IPv6 destination options header
 *	@iph: IPv6 header
 *	@destopt: destionation options header
 */
static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
{
	u8 *opt = (u8 *)destopt;
	int len = ipv6_optlen(destopt);
	int off = 0;
	int optlen = 0;

	off += 2;
	len -= 2;

	while (len > 0) {

		switch (opt[off]) {

		case IPV6_TLV_PAD0:
			optlen = 1;
			break;
		default:
			if (len < 2)
				goto bad;
			optlen = opt[off+1]+2;
			if (len < optlen)
				goto bad;

			/* Rearrange the source address in @iph and the
			 * addresses in home address option for final source.
			 * See 11.3.2 of RFC 3775 for details.
			 */
			if (opt[off] == IPV6_TLV_HAO) {
				struct in6_addr final_addr;
				struct ipv6_destopt_hao *hao;

				hao = (struct ipv6_destopt_hao *)&opt[off];
				if (hao->length != sizeof(hao->addr)) {
					if (net_ratelimit())
						printk(KERN_WARNING "destopt hao: invalid header length: %u\n", hao->length);
					goto bad;
				}
				ipv6_addr_copy(&final_addr, &hao->addr);
				ipv6_addr_copy(&hao->addr, &iph->saddr);
				ipv6_addr_copy(&iph->saddr, &final_addr);
			}
			break;
		}

		off += optlen;
		len -= optlen;
	}
	/* Note: ok if len == 0 */
bad:
	return;
}
#else
static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
#endif

/**
 *	ipv6_rearrange_rthdr - rearrange IPv6 routing header
 *	@iph: IPv6 header
 *	@rthdr: routing header
 *
 *	Rearrange the destination address in @iph and the addresses in @rthdr
 *	so that they appear in the order they will at the final destination.
 *	See Appendix A2 of RFC 2402 for details.
 */
static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
{
	int segments, segments_left;
	struct in6_addr *addrs;
	struct in6_addr final_addr;

	segments_left = rthdr->segments_left;
	if (segments_left == 0)
		return;
	rthdr->segments_left = 0;

	/* The value of rthdr->hdrlen has been verified either by the system
	 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
	 * packets.  So we can assume that it is even and that segments is
	 * greater than or equal to segments_left.
	 *
	 * For the same reason we can assume that this option is of type 0.
	 */
	segments = rthdr->hdrlen >> 1;

	addrs = ((struct rt0_hdr *)rthdr)->addr;
	ipv6_addr_copy(&final_addr, addrs + segments - 1);

	addrs += segments - segments_left;
	memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));

	ipv6_addr_copy(addrs, &iph->daddr);
	ipv6_addr_copy(&iph->daddr, &final_addr);
}

static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
{
	union {
		struct ipv6hdr *iph;
		struct ipv6_opt_hdr *opth;
		struct ipv6_rt_hdr *rth;
		char *raw;
	} exthdr = { .iph = iph };
	char *end = exthdr.raw + len;
	int nexthdr = iph->nexthdr;

	exthdr.iph++;

	while (exthdr.raw < end) {
		switch (nexthdr) {
		case NEXTHDR_DEST:
			if (dir == XFRM_POLICY_OUT)
				ipv6_rearrange_destopt(iph, exthdr.opth);
		case NEXTHDR_HOP:
			if (!zero_out_mutable_opts(exthdr.opth)) {
				LIMIT_NETDEBUG(
					KERN_WARNING "overrun %sopts\n",
					nexthdr == NEXTHDR_HOP ?
						"hop" : "dest");
				return -EINVAL;
			}
			break;

		case NEXTHDR_ROUTING:
			ipv6_rearrange_rthdr(iph, exthdr.rth);
			break;

		default :
			return 0;
		}

		nexthdr = exthdr.opth->nexthdr;
		exthdr.raw += ipv6_optlen(exthdr.opth);
	}

	return 0;
}

static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	int extlen;
	struct ipv6hdr *top_iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	u8 nexthdr;
	char tmp_base[8];
	struct {
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
		struct in6_addr saddr;
#endif
		struct in6_addr daddr;
		char hdrs[0];
	} *tmp_ext;

	top_iph = (struct ipv6hdr *)skb->data;
	top_iph->payload_len = htons(skb->len - sizeof(*top_iph));

	nexthdr = *skb_network_header(skb);
	*skb_network_header(skb) = IPPROTO_AH;

	/* When there are no extension headers, we only need to save the first
	 * 8 bytes of the base IP header.
	 */
	memcpy(tmp_base, top_iph, sizeof(tmp_base));

	tmp_ext = NULL;
	extlen = skb_transport_offset(skb) - sizeof(struct ipv6hdr);
	if (extlen) {
		extlen += sizeof(*tmp_ext);
		tmp_ext = kmalloc(extlen, GFP_ATOMIC);
		if (!tmp_ext) {
			err = -ENOMEM;
			goto error;
		}
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
		memcpy(tmp_ext, &top_iph->saddr, extlen);
#else
		memcpy(tmp_ext, &top_iph->daddr, extlen);
#endif
		err = ipv6_clear_mutable_options(top_iph,
						 extlen - sizeof(*tmp_ext) +
						 sizeof(*top_iph),
						 XFRM_POLICY_OUT);
		if (err)
			goto error_free_iph;
	}

	ah = (struct ip_auth_hdr *)skb_transport_header(skb);
	ah->nexthdr = nexthdr;

	top_iph->priority    = 0;
	top_iph->flow_lbl[0] = 0;
	top_iph->flow_lbl[1] = 0;
	top_iph->flow_lbl[2] = 0;
	top_iph->hop_limit   = 0;

	ahp = x->data;
	ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) +
				   ahp->icv_trunc_len) >> 2) - 2;

	ah->reserved = 0;
	ah->spi = x->id.spi;
	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
	err = ah_mac_digest(ahp, skb, ah->auth_data);
	if (err)
		goto error_free_iph;
	memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);

	err = 0;

	memcpy(top_iph, tmp_base, sizeof(tmp_base));
	if (tmp_ext) {
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
		memcpy(&top_iph->saddr, tmp_ext, extlen);
#else
		memcpy(&top_iph->daddr, tmp_ext, extlen);
#endif
error_free_iph:
		kfree(tmp_ext);
	}

error:
	return err;
}

static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
{
	/*
	 * Before process AH
	 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
	 * |<-------------->| hdr_len
	 *
	 * To erase AH:
	 * Keeping copy of cleared headers. After AH processing,
	 * Moving the pointer of skb->network_header by using skb_pull as long
	 * as AH header length. Then copy back the copy as long as hdr_len
	 * If destination header following AH exists, copy it into after [Ext2].
	 *
	 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
	 * There is offset of AH before IPv6 header after the process.
	 */

	struct ipv6_auth_hdr *ah;
	struct ipv6hdr *ip6h;
	struct ah_data *ahp;
	unsigned char *tmp_hdr = NULL;
	u16 hdr_len;
	u16 ah_hlen;
	int nexthdr;
	int err = -EINVAL;

	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_cloned(skb) &&
	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
		goto out;

	hdr_len = skb->data - skb_network_header(skb);
	ah = (struct ipv6_auth_hdr*)skb->data;
	ahp = x->data;
	nexthdr = ah->nexthdr;
	ah_hlen = (ah->hdrlen + 2) << 2;

	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_full_len) &&
	    ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len))
		goto out;

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	tmp_hdr = kmemdup(skb_network_header(skb), hdr_len, GFP_ATOMIC);
	if (!tmp_hdr)
		goto out;
	ip6h = ipv6_hdr(skb);
	if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
		goto free_out;
	ip6h->priority    = 0;
	ip6h->flow_lbl[0] = 0;
	ip6h->flow_lbl[1] = 0;
	ip6h->flow_lbl[2] = 0;
	ip6h->hop_limit   = 0;

	{
		u8 auth_data[MAX_AH_AUTH_LEN];

		memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
		memset(ah->auth_data, 0, ahp->icv_trunc_len);
		skb_push(skb, hdr_len);
		err = ah_mac_digest(ahp, skb, ah->auth_data);
		if (err)
			goto free_out;
		err = -EINVAL;
		if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
			LIMIT_NETDEBUG(KERN_WARNING "ipsec ah authentication error\n");
			x->stats.integrity_failed++;
			goto free_out;
		}
	}

	skb->network_header += ah_hlen;
	memcpy(skb_network_header(skb), tmp_hdr, hdr_len);
	skb->transport_header = skb->network_header;
	__skb_pull(skb, ah_hlen + hdr_len);

	kfree(tmp_hdr);

	return nexthdr;

free_out:
	kfree(tmp_hdr);
out:
	return err;
}

static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
		    int type, int code, int offset, __be32 info)
{
	struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
	struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
	struct xfrm_state *x;

	if (type != ICMPV6_DEST_UNREACH &&
	    type != ICMPV6_PKT_TOOBIG)
		return;

	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
	if (!x)
		return;

	NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/" NIP6_FMT "\n",
		 ntohl(ah->spi), NIP6(iph->daddr));

	xfrm_state_put(x);
}

static int ah6_init_state(struct xfrm_state *x)
{
	struct ah_data *ahp = NULL;
	struct xfrm_algo_desc *aalg_desc;
	struct crypto_hash *tfm;

	if (!x->aalg)
		goto error;

	if (x->encap)
		goto error;

	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
	if (ahp == NULL)
		return -ENOMEM;

	tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm))
		goto error;

	ahp->tfm = tfm;
	if (crypto_hash_setkey(tfm, x->aalg->alg_key,
			       (x->aalg->alg_key_len + 7) / 8))
		goto error;

	/*
	 * Lookup the algorithm description maintained by xfrm_algo,
	 * verify crypto transform properties, and store information
	 * we need for AH processing.  This lookup cannot fail here
	 * after a successful crypto_alloc_hash().
	 */
	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	BUG_ON(!aalg_desc);

	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
	    crypto_hash_digestsize(tfm)) {
		printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
		       x->aalg->alg_name, crypto_hash_digestsize(tfm),
		       aalg_desc->uinfo.auth.icv_fullbits/8);
		goto error;
	}

	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;

	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);

	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	if (!ahp->work_icv)
		goto error;

	x->props.header_len = XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct ipv6hdr);
	x->data = ahp;

	return 0;

error:
	if (ahp) {
		kfree(ahp->work_icv);
		crypto_free_hash(ahp->tfm);
		kfree(ahp);
	}
	return -EINVAL;
}

static void ah6_destroy(struct xfrm_state *x)
{
	struct ah_data *ahp = x->data;

	if (!ahp)
		return;

	kfree(ahp->work_icv);
	ahp->work_icv = NULL;
	crypto_free_hash(ahp->tfm);
	ahp->tfm = NULL;
	kfree(ahp);
}

static struct xfrm_type ah6_type =
{
	.description	= "AH6",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_AH,
	.flags		= XFRM_TYPE_REPLAY_PROT,
	.init_state	= ah6_init_state,
	.destructor	= ah6_destroy,
	.input		= ah6_input,
	.output		= ah6_output,
	.hdr_offset	= xfrm6_find_1stfragopt,
};

static struct inet6_protocol ah6_protocol = {
	.handler	=	xfrm6_rcv,
	.err_handler	=	ah6_err,
	.flags		=	INET6_PROTO_NOPOLICY,
};

static int __init ah6_init(void)
{
	if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
		printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
		return -EAGAIN;
	}

	if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
		printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
		xfrm_unregister_type(&ah6_type, AF_INET6);
		return -EAGAIN;
	}

	return 0;
}

static void __exit ah6_fini(void)
{
	if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
		printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");

	if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
		printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");

}

module_init(ah6_init);
module_exit(ah6_fini);

MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* Copyright (C)2002 USAGI/WIDE Project
1ab1457c	3	*
1da177e4 LT	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
1ab1457c	8	*
1da177e4 LT	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1ab1457c	13	*
1da177e4 LT	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	17	*
	18	* Authors
	19	*
1ab1457c	20	* Mitsuru KANDA @USAGI : IPv6 Support
1da177e4 LT	21	* Kazunori MIYAZAWA @USAGI :
1da177e4 LT	22	* Kunihiro Ishiguro <[email protected]>
1ab1457c	23	*
1da177e4 LT	24	* This file is derived from net/ipv4/ah.c.
	25	*/
	26
1da177e4 LT	27	#include <linux/module.h>
	28	#include <net/ip.h>
	29	#include <net/ah.h>
	30	#include <linux/crypto.h>
	31	#include <linux/pfkeyv2.h>
	32	#include <linux/string.h>
	33	#include <net/icmp.h>
	34	#include <net/ipv6.h>
14c85021	35	#include <net/protocol.h>
1da177e4 LT	36	#include <net/xfrm.h>
	37	#include <asm/scatterlist.h>
	38
	39	static int zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
	40	{
	41	u8 opt = (u8 )opthdr;
	42	int len = ipv6_optlen(opthdr);
	43	int off = 0;
	44	int optlen = 0;
	45
	46	off += 2;
	47	len -= 2;
	48
	49	while (len > 0) {
	50
	51	switch (opt[off]) {
	52
	53	case IPV6_TLV_PAD0:
	54	optlen = 1;
	55	break;
	56	default:
1ab1457c	57	if (len < 2)
1da177e4 LT	58	goto bad;
	59	optlen = opt[off+1]+2;
	60	if (len < optlen)
	61	goto bad;
	62	if (opt[off] & 0x20)
	63	memset(&opt[off+2], 0, opt[off+1]);
	64	break;
	65	}
	66
	67	off += optlen;
	68	len -= optlen;
	69	}
	70	if (len == 0)
	71	return 1;
	72
	73	bad:
	74	return 0;
	75	}
	76
59fbb3a6	77	#if defined(CONFIG_IPV6_MIP6) \|\| defined(CONFIG_IPV6_MIP6_MODULE)
27637df9 MN	78	/**
	79	* ipv6_rearrange_destopt - rearrange IPv6 destination options header
	80	* @iph: IPv6 header
	81	* @destopt: destionation options header
	82	*/
	83	static void ipv6_rearrange_destopt(struct ipv6hdr iph, struct ipv6_opt_hdr destopt)
	84	{
	85	u8 opt = (u8 )destopt;
	86	int len = ipv6_optlen(destopt);
	87	int off = 0;
	88	int optlen = 0;
	89
	90	off += 2;
	91	len -= 2;
	92
	93	while (len > 0) {
	94
	95	switch (opt[off]) {
	96
	97	case IPV6_TLV_PAD0:
	98	optlen = 1;
	99	break;
	100	default:
	101	if (len < 2)
	102	goto bad;
	103	optlen = opt[off+1]+2;
	104	if (len < optlen)
	105	goto bad;
	106
	107	/* Rearrange the source address in @iph and the
	108	* addresses in home address option for final source.
	109	* See 11.3.2 of RFC 3775 for details.
	110	*/
	111	if (opt[off] == IPV6_TLV_HAO) {
	112	struct in6_addr final_addr;
	113	struct ipv6_destopt_hao *hao;
	114
	115	hao = (struct ipv6_destopt_hao *)&opt[off];
	116	if (hao->length != sizeof(hao->addr)) {
	117	if (net_ratelimit())
	118	printk(KERN_WARNING "destopt hao: invalid header length: %u\n", hao->length);
	119	goto bad;
	120	}
	121	ipv6_addr_copy(&final_addr, &hao->addr);
	122	ipv6_addr_copy(&hao->addr, &iph->saddr);
	123	ipv6_addr_copy(&iph->saddr, &final_addr);
	124	}
	125	break;
	126	}
	127
	128	off += optlen;
	129	len -= optlen;
	130	}
e731c248	131	/* Note: ok if len == 0 */
27637df9 MN	132	bad:
	133	return;
	134	}
136ebf08 MN	135	#else
136ebf08 MN	136	static void ipv6_rearrange_destopt(struct ipv6hdr iph, struct ipv6_opt_hdr destopt) {}
27637df9 MN	137	#endif
27637df9 MN	138
1da177e4 LT	139	/**
	140	* ipv6_rearrange_rthdr - rearrange IPv6 routing header
	141	* @iph: IPv6 header
	142	* @rthdr: routing header
	143	*
	144	* Rearrange the destination address in @iph and the addresses in @rthdr
	145	* so that they appear in the order they will at the final destination.
	146	* See Appendix A2 of RFC 2402 for details.
	147	*/
	148	static void ipv6_rearrange_rthdr(struct ipv6hdr iph, struct ipv6_rt_hdr rthdr)
	149	{
	150	int segments, segments_left;
	151	struct in6_addr *addrs;
	152	struct in6_addr final_addr;
	153
	154	segments_left = rthdr->segments_left;
	155	if (segments_left == 0)
	156	return;
1ab1457c	157	rthdr->segments_left = 0;
1da177e4 LT	158
	159	/* The value of rthdr->hdrlen has been verified either by the system
	160	* call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
	161	* packets. So we can assume that it is even and that segments is
	162	* greater than or equal to segments_left.
	163	*
	164	* For the same reason we can assume that this option is of type 0.
	165	*/
	166	segments = rthdr->hdrlen >> 1;
	167
	168	addrs = ((struct rt0_hdr *)rthdr)->addr;
	169	ipv6_addr_copy(&final_addr, addrs + segments - 1);
	170
	171	addrs += segments - segments_left;
	172	memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
	173
	174	ipv6_addr_copy(addrs, &iph->daddr);
	175	ipv6_addr_copy(&iph->daddr, &final_addr);
	176	}
	177
27637df9	178	static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
1da177e4 LT	179	{
	180	union {
	181	struct ipv6hdr *iph;
	182	struct ipv6_opt_hdr *opth;
	183	struct ipv6_rt_hdr *rth;
	184	char *raw;
	185	} exthdr = { .iph = iph };
	186	char *end = exthdr.raw + len;
	187	int nexthdr = iph->nexthdr;
	188
	189	exthdr.iph++;
	190
	191	while (exthdr.raw < end) {
	192	switch (nexthdr) {
27637df9 MN	193	case NEXTHDR_DEST:
	194	if (dir == XFRM_POLICY_OUT)
	195	ipv6_rearrange_destopt(iph, exthdr.opth);
1da177e4	196	case NEXTHDR_HOP:
1da177e4	197	if (!zero_out_mutable_opts(exthdr.opth)) {
64ce2073	198	LIMIT_NETDEBUG(
1da177e4 LT	199	KERN_WARNING "overrun %sopts\n",
1da177e4 LT	200	nexthdr == NEXTHDR_HOP ?
64ce2073	201	"hop" : "dest");
1da177e4 LT	202	return -EINVAL;
	203	}
	204	break;
	205
	206	case NEXTHDR_ROUTING:
	207	ipv6_rearrange_rthdr(iph, exthdr.rth);
	208	break;
	209
	210	default :
	211	return 0;
	212	}
	213
	214	nexthdr = exthdr.opth->nexthdr;
	215	exthdr.raw += ipv6_optlen(exthdr.opth);
	216	}
	217
	218	return 0;
	219	}
	220
	221	static int ah6_output(struct xfrm_state x, struct sk_buff skb)
	222	{
	223	int err;
	224	int extlen;
	225	struct ipv6hdr *top_iph;
	226	struct ip_auth_hdr *ah;
	227	struct ah_data *ahp;
	228	u8 nexthdr;
	229	char tmp_base[8];
	230	struct {
59fbb3a6	231	#if defined(CONFIG_IPV6_MIP6) \|\| defined(CONFIG_IPV6_MIP6_MODULE)
27637df9 MN	232	struct in6_addr saddr;
27637df9 MN	233	#endif
1da177e4 LT	234	struct in6_addr daddr;
	235	char hdrs[0];
	236	} *tmp_ext;
	237
	238	top_iph = (struct ipv6hdr *)skb->data;
	239	top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
	240
d56f90a7 ACM	241	nexthdr = *skb_network_header(skb);
d56f90a7 ACM	242	*skb_network_header(skb) = IPPROTO_AH;
1da177e4 LT	243
	244	/* When there are no extension headers, we only need to save the first
	245	* 8 bytes of the base IP header.
	246	*/
	247	memcpy(tmp_base, top_iph, sizeof(tmp_base));
	248
	249	tmp_ext = NULL;
144466bd	250	extlen = skb_transport_offset(skb) - sizeof(struct ipv6hdr);
1da177e4 LT	251	if (extlen) {
	252	extlen += sizeof(*tmp_ext);
	253	tmp_ext = kmalloc(extlen, GFP_ATOMIC);
	254	if (!tmp_ext) {
	255	err = -ENOMEM;
	256	goto error;
	257	}
59fbb3a6	258	#if defined(CONFIG_IPV6_MIP6) \|\| defined(CONFIG_IPV6_MIP6_MODULE)
27637df9	259	memcpy(tmp_ext, &top_iph->saddr, extlen);
27637df9	260	#else
1da177e4	261	memcpy(tmp_ext, &top_iph->daddr, extlen);
e731c248	262	#endif
1da177e4 LT	263	err = ipv6_clear_mutable_options(top_iph,
1da177e4 LT	264	extlen - sizeof(*tmp_ext) +
e731c248 YH	265	sizeof(*top_iph),
e731c248 YH	266	XFRM_POLICY_OUT);
1da177e4 LT	267	if (err)
	268	goto error_free_iph;
	269	}
	270
9c70220b	271	ah = (struct ip_auth_hdr *)skb_transport_header(skb);
1da177e4 LT	272	ah->nexthdr = nexthdr;
	273
	274	top_iph->priority = 0;
	275	top_iph->flow_lbl[0] = 0;
	276	top_iph->flow_lbl[1] = 0;
	277	top_iph->flow_lbl[2] = 0;
	278	top_iph->hop_limit = 0;
	279
	280	ahp = x->data;
1ab1457c	281	ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) +
1da177e4 LT	282	ahp->icv_trunc_len) >> 2) - 2;
	283
	284	ah->reserved = 0;
	285	ah->spi = x->id.spi;
436a0a40	286	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
07d4ee58 HX	287	err = ah_mac_digest(ahp, skb, ah->auth_data);
	288	if (err)
	289	goto error_free_iph;
	290	memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
1da177e4 LT	291
	292	err = 0;
	293
	294	memcpy(top_iph, tmp_base, sizeof(tmp_base));
	295	if (tmp_ext) {
59fbb3a6	296	#if defined(CONFIG_IPV6_MIP6) \|\| defined(CONFIG_IPV6_MIP6_MODULE)
27637df9 MN	297	memcpy(&top_iph->saddr, tmp_ext, extlen);
27637df9 MN	298	#else
1da177e4	299	memcpy(&top_iph->daddr, tmp_ext, extlen);
27637df9	300	#endif
1da177e4 LT	301	error_free_iph:
	302	kfree(tmp_ext);
	303	}
	304
	305	error:
	306	return err;
	307	}
	308
e695633e	309	static int ah6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	310	{
	311	/*
	312	* Before process AH
	313	* [IPv6][Ext1][Ext2][AH][Dest][Payload]
	314	* \|<-------------->\| hdr_len
	315	*
	316	* To erase AH:
	317	* Keeping copy of cleared headers. After AH processing,
b0e380b1 ACM	318	* Moving the pointer of skb->network_header by using skb_pull as long
b0e380b1 ACM	319	* as AH header length. Then copy back the copy as long as hdr_len
1da177e4	320	* If destination header following AH exists, copy it into after [Ext2].
1ab1457c	321	*
1da177e4 LT	322	* \|<>\|[IPv6][Ext1][Ext2][Dest][Payload]
	323	* There is offset of AH before IPv6 header after the process.
	324	*/
	325
	326	struct ipv6_auth_hdr *ah;
0660e03f	327	struct ipv6hdr *ip6h;
1da177e4 LT	328	struct ah_data *ahp;
	329	unsigned char *tmp_hdr = NULL;
	330	u16 hdr_len;
	331	u16 ah_hlen;
	332	int nexthdr;
07d4ee58	333	int err = -EINVAL;
1da177e4 LT	334
	335	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
	336	goto out;
	337
	338	/* We are going to _remove_ AH header to keep sockets happy,
	339	* so... Later this can change. */
	340	if (skb_cloned(skb) &&
	341	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	342	goto out;
	343
d56f90a7	344	hdr_len = skb->data - skb_network_header(skb);
1da177e4 LT	345	ah = (struct ipv6_auth_hdr*)skb->data;
	346	ahp = x->data;
	347	nexthdr = ah->nexthdr;
	348	ah_hlen = (ah->hdrlen + 2) << 2;
	349
1ab1457c YH	350	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_full_len) &&
	351	ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len))
	352	goto out;
1da177e4 LT	353
	354	if (!pskb_may_pull(skb, ah_hlen))
	355	goto out;
	356
d56f90a7	357	tmp_hdr = kmemdup(skb_network_header(skb), hdr_len, GFP_ATOMIC);
1da177e4 LT	358	if (!tmp_hdr)
1da177e4 LT	359	goto out;
0660e03f ACM	360	ip6h = ipv6_hdr(skb);
0660e03f ACM	361	if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
27637df9	362	goto free_out;
0660e03f ACM	363	ip6h->priority = 0;
	364	ip6h->flow_lbl[0] = 0;
	365	ip6h->flow_lbl[1] = 0;
	366	ip6h->flow_lbl[2] = 0;
	367	ip6h->hop_limit = 0;
1da177e4	368
1ab1457c	369	{
1da177e4 LT	370	u8 auth_data[MAX_AH_AUTH_LEN];
	371
	372	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	373	memset(ah->auth_data, 0, ahp->icv_trunc_len);
31a4ab93	374	skb_push(skb, hdr_len);
07d4ee58 HX	375	err = ah_mac_digest(ahp, skb, ah->auth_data);
	376	if (err)
	377	goto free_out;
	378	err = -EINVAL;
	379	if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
64ce2073	380	LIMIT_NETDEBUG(KERN_WARNING "ipsec ah authentication error\n");
1da177e4 LT	381	x->stats.integrity_failed++;
	382	goto free_out;
	383	}
	384	}
	385
b0e380b1	386	skb->network_header += ah_hlen;
d56f90a7	387	memcpy(skb_network_header(skb), tmp_hdr, hdr_len);
b0e380b1	388	skb->transport_header = skb->network_header;
31a4ab93	389	__skb_pull(skb, ah_hlen + hdr_len);
1da177e4 LT	390
	391	kfree(tmp_hdr);
	392
	393	return nexthdr;
	394
	395	free_out:
	396	kfree(tmp_hdr);
	397	out:
07d4ee58	398	return err;
1da177e4 LT	399	}
1da177e4 LT	400
1ab1457c YH	401	static void ah6_err(struct sk_buff skb, struct inet6_skb_parm opt,
1ab1457c YH	402	int type, int code, int offset, __be32 info)
1da177e4 LT	403	{
	404	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	405	struct ip_auth_hdr ah = (struct ip_auth_hdr)(skb->data+offset);
	406	struct xfrm_state *x;
	407
	408	if (type != ICMPV6_DEST_UNREACH &&
	409	type != ICMPV6_PKT_TOOBIG)
	410	return;
	411
	412	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
	413	if (!x)
	414	return;
	415
46b86a2d	416	NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/" NIP6_FMT "\n",
64ce2073	417	ntohl(ah->spi), NIP6(iph->daddr));
1da177e4 LT	418
	419	xfrm_state_put(x);
	420	}
	421
72cb6962	422	static int ah6_init_state(struct xfrm_state *x)
1da177e4 LT	423	{
	424	struct ah_data *ahp = NULL;
	425	struct xfrm_algo_desc *aalg_desc;
07d4ee58	426	struct crypto_hash *tfm;
1da177e4 LT	427
	428	if (!x->aalg)
	429	goto error;
	430
1da177e4 LT	431	if (x->encap)
	432	goto error;
	433
0c600eda	434	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
1da177e4 LT	435	if (ahp == NULL)
	436	return -ENOMEM;
	437
07d4ee58 HX	438	tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
	439	if (IS_ERR(tfm))
	440	goto error;
	441
	442	ahp->tfm = tfm;
bc31d3b2 HX	443	if (crypto_hash_setkey(tfm, x->aalg->alg_key,
bc31d3b2 HX	444	(x->aalg->alg_key_len + 7) / 8))
1da177e4	445	goto error;
1ab1457c	446
1da177e4 LT	447	/*
	448	* Lookup the algorithm description maintained by xfrm_algo,
	449	* verify crypto transform properties, and store information
	450	* we need for AH processing. This lookup cannot fail here
07d4ee58	451	* after a successful crypto_alloc_hash().
1da177e4 LT	452	*/
	453	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	454	BUG_ON(!aalg_desc);
	455
	456	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58	457	crypto_hash_digestsize(tfm)) {
1da177e4	458	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
07d4ee58	459	x->aalg->alg_name, crypto_hash_digestsize(tfm),
1da177e4 LT	460	aalg_desc->uinfo.auth.icv_fullbits/8);
	461	goto error;
	462	}
1ab1457c	463
1da177e4 LT	464	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
1da177e4 LT	465	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
1ab1457c	466
1da177e4	467	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
1ab1457c	468
1da177e4 LT	469	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	470	if (!ahp->work_icv)
	471	goto error;
1ab1457c	472
1da177e4	473	x->props.header_len = XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len);
7e49e6de	474	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	475	x->props.header_len += sizeof(struct ipv6hdr);
	476	x->data = ahp;
	477
	478	return 0;
	479
	480	error:
	481	if (ahp) {
573dbd95	482	kfree(ahp->work_icv);
07d4ee58	483	crypto_free_hash(ahp->tfm);
1da177e4 LT	484	kfree(ahp);
	485	}
	486	return -EINVAL;
	487	}
	488
	489	static void ah6_destroy(struct xfrm_state *x)
	490	{
	491	struct ah_data *ahp = x->data;
	492
	493	if (!ahp)
	494	return;
	495
573dbd95 JJ	496	kfree(ahp->work_icv);
573dbd95 JJ	497	ahp->work_icv = NULL;
07d4ee58	498	crypto_free_hash(ahp->tfm);
573dbd95	499	ahp->tfm = NULL;
1da177e4 LT	500	kfree(ahp);
	501	}
	502
	503	static struct xfrm_type ah6_type =
	504	{
	505	.description = "AH6",
	506	.owner = THIS_MODULE,
	507	.proto = IPPROTO_AH,
436a0a40	508	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	509	.init_state = ah6_init_state,
	510	.destructor = ah6_destroy,
	511	.input = ah6_input,
aee5adb4 MN	512	.output = ah6_output,
aee5adb4 MN	513	.hdr_offset = xfrm6_find_1stfragopt,
1da177e4 LT	514	};
	515
	516	static struct inet6_protocol ah6_protocol = {
	517	.handler = xfrm6_rcv,
	518	.err_handler = ah6_err,
	519	.flags = INET6_PROTO_NOPOLICY,
	520	};
	521
	522	static int __init ah6_init(void)
	523	{
	524	if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
	525	printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
	526	return -EAGAIN;
	527	}
	528
	529	if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
	530	printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
	531	xfrm_unregister_type(&ah6_type, AF_INET6);
	532	return -EAGAIN;
	533	}
	534
	535	return 0;
	536	}
	537
	538	static void __exit ah6_fini(void)
	539	{
	540	if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
	541	printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");
	542
	543	if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
	544	printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");
	545
	546	}
	547
	548	module_init(ah6_init);
	549	module_exit(ah6_fini);
	550
	551	MODULE_LICENSE("GPL");
d3d6dd3a	552	MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);