[linux-block.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 <kunihiro@ipinfusion.com>
 * 	
 * 	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;
}

#ifdef CONFIG_IPV6_MIP6
/**
 *	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;
}
#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:
#ifdef CONFIG_IPV6_MIP6
			if (dir == XFRM_POLICY_OUT)
				ipv6_rearrange_destopt(iph, exthdr.opth);
#endif
		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 {
#ifdef CONFIG_IPV6_MIP6
		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->nh.raw;
	*skb->nh.raw = 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->h.raw - (unsigned char *)(top_iph + 1);
	if (extlen) {
		extlen += sizeof(*tmp_ext);
		tmp_ext = kmalloc(extlen, GFP_ATOMIC);
		if (!tmp_ext) {
			err = -ENOMEM;
			goto error;
		}
#ifdef CONFIG_IPV6_MIP6
		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->h.raw;
	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(++x->replay.oseq);
	xfrm_aevent_doreplay(x);
	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) {
#ifdef CONFIG_IPV6_MIP6
		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->nh.raw 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 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->nh.raw;
	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->nh.raw, hdr_len, GFP_ATOMIC);
	if (!tmp_hdr)
		goto out;
	if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len, XFRM_POLICY_IN))
		goto free_out;
	skb->nh.ipv6h->priority    = 0;
	skb->nh.ipv6h->flow_lbl[0] = 0;
	skb->nh.ipv6h->flow_lbl[1] = 0;
	skb->nh.ipv6h->flow_lbl[2] = 0;
	skb->nh.ipv6h->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->h.raw = memcpy(skb->nh.raw += ah_hlen, tmp_hdr, hdr_len);
	__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;

	/* null auth can use a zero length key */
	if (x->aalg->alg_key_len > 512)
		goto error;

	if (x->encap)
		goto error;

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

	ahp->key = x->aalg->alg_key;
	ahp->key_len = (x->aalg->alg_key_len+7)/8;
	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, ahp->key, ahp->key_len))
		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,
	.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");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright (C)2002 USAGI/WIDE Project
	3	*
	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.
	8	*
	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.
	13	*
	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	*
	20	* Mitsuru KANDA @USAGI : IPv6 Support
	21	* Kazunori MIYAZAWA @USAGI :
	22	* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
	23	*
	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:
	57	if (len < 2)
	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
27637df9 MN	77	#ifdef CONFIG_IPV6_MIP6
	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	}
	135	#endif
	136
1da177e4 LT	137	/**
	138	* ipv6_rearrange_rthdr - rearrange IPv6 routing header
	139	* @iph: IPv6 header
	140	* @rthdr: routing header
	141	*
	142	* Rearrange the destination address in @iph and the addresses in @rthdr
	143	* so that they appear in the order they will at the final destination.
	144	* See Appendix A2 of RFC 2402 for details.
	145	*/
	146	static void ipv6_rearrange_rthdr(struct ipv6hdr iph, struct ipv6_rt_hdr rthdr)
	147	{
	148	int segments, segments_left;
	149	struct in6_addr *addrs;
	150	struct in6_addr final_addr;
	151
	152	segments_left = rthdr->segments_left;
	153	if (segments_left == 0)
	154	return;
	155	rthdr->segments_left = 0;
	156
	157	/* The value of rthdr->hdrlen has been verified either by the system
	158	* call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
	159	* packets. So we can assume that it is even and that segments is
	160	* greater than or equal to segments_left.
	161	*
	162	* For the same reason we can assume that this option is of type 0.
	163	*/
	164	segments = rthdr->hdrlen >> 1;
	165
	166	addrs = ((struct rt0_hdr *)rthdr)->addr;
	167	ipv6_addr_copy(&final_addr, addrs + segments - 1);
	168
	169	addrs += segments - segments_left;
	170	memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
	171
	172	ipv6_addr_copy(addrs, &iph->daddr);
	173	ipv6_addr_copy(&iph->daddr, &final_addr);
	174	}
	175
27637df9	176	static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
1da177e4 LT	177	{
	178	union {
	179	struct ipv6hdr *iph;
	180	struct ipv6_opt_hdr *opth;
	181	struct ipv6_rt_hdr *rth;
	182	char *raw;
	183	} exthdr = { .iph = iph };
	184	char *end = exthdr.raw + len;
	185	int nexthdr = iph->nexthdr;
	186
	187	exthdr.iph++;
	188
	189	while (exthdr.raw < end) {
	190	switch (nexthdr) {
27637df9	191	case NEXTHDR_DEST:
e731c248	192	#ifdef CONFIG_IPV6_MIP6
27637df9 MN	193	if (dir == XFRM_POLICY_OUT)
27637df9 MN	194	ipv6_rearrange_destopt(iph, exthdr.opth);
e731c248	195	#endif
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 {
27637df9 MN	231	#ifdef CONFIG_IPV6_MIP6
	232	struct in6_addr saddr;
	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
	241	nexthdr = *skb->nh.raw;
	242	*skb->nh.raw = IPPROTO_AH;
	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;
	250	extlen = skb->h.raw - (unsigned char *)(top_iph + 1);
	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	}
27637df9 MN	258	#ifdef CONFIG_IPV6_MIP6
27637df9 MN	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
	271	ah = (struct ip_auth_hdr *)skb->h.raw;
	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;
	281	ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) +
	282	ahp->icv_trunc_len) >> 2) - 2;
	283
	284	ah->reserved = 0;
	285	ah->spi = x->id.spi;
	286	ah->seq_no = htonl(++x->replay.oseq);
9500e8a8	287	xfrm_aevent_doreplay(x);
07d4ee58 HX	288	err = ah_mac_digest(ahp, skb, ah->auth_data);
	289	if (err)
	290	goto error_free_iph;
	291	memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
1da177e4 LT	292
	293	err = 0;
	294
	295	memcpy(top_iph, tmp_base, sizeof(tmp_base));
	296	if (tmp_ext) {
27637df9 MN	297	#ifdef CONFIG_IPV6_MIP6
	298	memcpy(&top_iph->saddr, tmp_ext, extlen);
	299	#else
1da177e4	300	memcpy(&top_iph->daddr, tmp_ext, extlen);
27637df9	301	#endif
1da177e4 LT	302	error_free_iph:
	303	kfree(tmp_ext);
	304	}
	305
	306	error:
	307	return err;
	308	}
	309
e695633e	310	static int ah6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	311	{
	312	/*
	313	* Before process AH
	314	* [IPv6][Ext1][Ext2][AH][Dest][Payload]
	315	* \|<-------------->\| hdr_len
	316	*
	317	* To erase AH:
	318	* Keeping copy of cleared headers. After AH processing,
	319	* Moving the pointer of skb->nh.raw by using skb_pull as long as AH
	320	* header length. Then copy back the copy as long as hdr_len
	321	* If destination header following AH exists, copy it into after [Ext2].
	322	*
	323	* \|<>\|[IPv6][Ext1][Ext2][Dest][Payload]
	324	* There is offset of AH before IPv6 header after the process.
	325	*/
	326
	327	struct ipv6_auth_hdr *ah;
	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
	344	hdr_len = skb->data - skb->nh.raw;
	345	ah = (struct ipv6_auth_hdr*)skb->data;
	346	ahp = x->data;
	347	nexthdr = ah->nexthdr;
	348	ah_hlen = (ah->hdrlen + 2) << 2;
	349
	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;
	353
	354	if (!pskb_may_pull(skb, ah_hlen))
	355	goto out;
	356
af879cc7	357	tmp_hdr = kmemdup(skb->nh.raw, hdr_len, GFP_ATOMIC);
1da177e4 LT	358	if (!tmp_hdr)
1da177e4 LT	359	goto out;
27637df9 MN	360	if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len, XFRM_POLICY_IN))
27637df9 MN	361	goto free_out;
1da177e4 LT	362	skb->nh.ipv6h->priority = 0;
	363	skb->nh.ipv6h->flow_lbl[0] = 0;
	364	skb->nh.ipv6h->flow_lbl[1] = 0;
	365	skb->nh.ipv6h->flow_lbl[2] = 0;
	366	skb->nh.ipv6h->hop_limit = 0;
	367
	368	{
	369	u8 auth_data[MAX_AH_AUTH_LEN];
	370
	371	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	372	memset(ah->auth_data, 0, ahp->icv_trunc_len);
31a4ab93	373	skb_push(skb, hdr_len);
07d4ee58 HX	374	err = ah_mac_digest(ahp, skb, ah->auth_data);
	375	if (err)
	376	goto free_out;
	377	err = -EINVAL;
	378	if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
64ce2073	379	LIMIT_NETDEBUG(KERN_WARNING "ipsec ah authentication error\n");
1da177e4 LT	380	x->stats.integrity_failed++;
	381	goto free_out;
	382	}
	383	}
	384
31a4ab93 HX	385	skb->h.raw = memcpy(skb->nh.raw += ah_hlen, tmp_hdr, hdr_len);
31a4ab93 HX	386	__skb_pull(skb, ah_hlen + hdr_len);
1da177e4 LT	387
	388	kfree(tmp_hdr);
	389
	390	return nexthdr;
	391
	392	free_out:
	393	kfree(tmp_hdr);
	394	out:
07d4ee58	395	return err;
1da177e4 LT	396	}
	397
	398	static void ah6_err(struct sk_buff skb, struct inet6_skb_parm opt,
04ce6909	399	int type, int code, int offset, __be32 info)
1da177e4 LT	400	{
	401	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	402	struct ip_auth_hdr ah = (struct ip_auth_hdr)(skb->data+offset);
	403	struct xfrm_state *x;
	404
	405	if (type != ICMPV6_DEST_UNREACH &&
	406	type != ICMPV6_PKT_TOOBIG)
	407	return;
	408
	409	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
	410	if (!x)
	411	return;
	412
46b86a2d	413	NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/" NIP6_FMT "\n",
64ce2073	414	ntohl(ah->spi), NIP6(iph->daddr));
1da177e4 LT	415
	416	xfrm_state_put(x);
	417	}
	418
72cb6962	419	static int ah6_init_state(struct xfrm_state *x)
1da177e4 LT	420	{
	421	struct ah_data *ahp = NULL;
	422	struct xfrm_algo_desc *aalg_desc;
07d4ee58	423	struct crypto_hash *tfm;
1da177e4 LT	424
	425	if (!x->aalg)
	426	goto error;
	427
	428	/* null auth can use a zero length key */
	429	if (x->aalg->alg_key_len > 512)
	430	goto error;
	431
	432	if (x->encap)
	433	goto error;
	434
0c600eda	435	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
1da177e4 LT	436	if (ahp == NULL)
	437	return -ENOMEM;
	438
1da177e4 LT	439	ahp->key = x->aalg->alg_key;
1da177e4 LT	440	ahp->key_len = (x->aalg->alg_key_len+7)/8;
07d4ee58 HX	441	tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
	442	if (IS_ERR(tfm))
	443	goto error;
	444
	445	ahp->tfm = tfm;
	446	if (crypto_hash_setkey(tfm, ahp->key, ahp->key_len))
1da177e4	447	goto error;
1da177e4 LT	448
	449	/*
	450	* Lookup the algorithm description maintained by xfrm_algo,
	451	* verify crypto transform properties, and store information
	452	* we need for AH processing. This lookup cannot fail here
07d4ee58	453	* after a successful crypto_alloc_hash().
1da177e4 LT	454	*/
	455	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	456	BUG_ON(!aalg_desc);
	457
	458	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58	459	crypto_hash_digestsize(tfm)) {
1da177e4	460	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
07d4ee58	461	x->aalg->alg_name, crypto_hash_digestsize(tfm),
1da177e4 LT	462	aalg_desc->uinfo.auth.icv_fullbits/8);
	463	goto error;
	464	}
	465
	466	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	467	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
	468
	469	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
	470
	471	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	472	if (!ahp->work_icv)
	473	goto error;
	474
	475	x->props.header_len = XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len);
7e49e6de	476	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	477	x->props.header_len += sizeof(struct ipv6hdr);
	478	x->data = ahp;
	479
	480	return 0;
	481
	482	error:
	483	if (ahp) {
573dbd95	484	kfree(ahp->work_icv);
07d4ee58	485	crypto_free_hash(ahp->tfm);
1da177e4 LT	486	kfree(ahp);
	487	}
	488	return -EINVAL;
	489	}
	490
	491	static void ah6_destroy(struct xfrm_state *x)
	492	{
	493	struct ah_data *ahp = x->data;
	494
	495	if (!ahp)
	496	return;
	497
573dbd95 JJ	498	kfree(ahp->work_icv);
573dbd95 JJ	499	ahp->work_icv = NULL;
07d4ee58	500	crypto_free_hash(ahp->tfm);
573dbd95	501	ahp->tfm = NULL;
1da177e4 LT	502	kfree(ahp);
	503	}
	504
	505	static struct xfrm_type ah6_type =
	506	{
	507	.description = "AH6",
	508	.owner = THIS_MODULE,
	509	.proto = IPPROTO_AH,
	510	.init_state = ah6_init_state,
	511	.destructor = ah6_destroy,
	512	.input = ah6_input,
aee5adb4 MN	513	.output = ah6_output,
aee5adb4 MN	514	.hdr_offset = xfrm6_find_1stfragopt,
1da177e4 LT	515	};
	516
	517	static struct inet6_protocol ah6_protocol = {
	518	.handler = xfrm6_rcv,
	519	.err_handler = ah6_err,
	520	.flags = INET6_PROTO_NOPOLICY,
	521	};
	522
	523	static int __init ah6_init(void)
	524	{
	525	if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
	526	printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
	527	return -EAGAIN;
	528	}
	529
	530	if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
	531	printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
	532	xfrm_unregister_type(&ah6_type, AF_INET6);
	533	return -EAGAIN;
	534	}
	535
	536	return 0;
	537	}
	538
	539	static void __exit ah6_fini(void)
	540	{
	541	if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
	542	printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");
	543
	544	if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
	545	printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");
	546
	547	}
	548
	549	module_init(ah6_init);
	550	module_exit(ah6_fini);
	551
	552	MODULE_LICENSE("GPL");