[linux.git] / net / ipv6 / esp6.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/esp.c
 */

#include <linux/err.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/esp.h>
#include <asm/scatterlist.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/random.h>
#include <net/icmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <linux/icmpv6.h>

static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct ipv6hdr *top_iph;
	struct ipv6_esp_hdr *esph;
	struct crypto_blkcipher *tfm;
	struct blkcipher_desc desc;
	struct sk_buff *trailer;
	int blksize;
	int clen;
	int alen;
	int nfrags;
	u8 *tail;
	struct esp_data *esp = x->data;
	int hdr_len = (skb_transport_offset(skb) +
		       sizeof(*esph) + esp->conf.ivlen);

	/* Strip IP+ESP header. */
	__skb_pull(skb, hdr_len);

	/* Now skb is pure payload to encrypt */
	err = -ENOMEM;

	/* Round to block size */
	clen = skb->len;

	alen = esp->auth.icv_trunc_len;
	tfm = esp->conf.tfm;
	desc.tfm = tfm;
	desc.flags = 0;
	blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
	clen = ALIGN(clen + 2, blksize);
	if (esp->conf.padlen)
		clen = ALIGN(clen, esp->conf.padlen);

	if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
		goto error;
	}

	/* Fill padding... */
	tail = skb_tail_pointer(trailer);
	do {
		int i;
		for (i=0; i<clen-skb->len - 2; i++)
			tail[i] = i + 1;
	} while (0);
	tail[clen-skb->len - 2] = (clen - skb->len) - 2;
	pskb_put(skb, trailer, clen - skb->len);

	top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
	esph = (struct ipv6_esp_hdr *)skb_transport_header(skb);
	top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
	*(skb_tail_pointer(trailer) - 1) = *skb_network_header(skb);
	*skb_network_header(skb) = IPPROTO_ESP;

	esph->spi = x->id.spi;
	esph->seq_no = htonl(++x->replay.oseq);
	xfrm_aevent_doreplay(x);

	if (esp->conf.ivlen) {
		if (unlikely(!esp->conf.ivinitted)) {
			get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
			esp->conf.ivinitted = 1;
		}
		crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
	}

	do {
		struct scatterlist *sg = &esp->sgbuf[0];

		if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
			sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
			if (!sg)
				goto error;
		}
		skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
		err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
		if (unlikely(sg != &esp->sgbuf[0]))
			kfree(sg);
	} while (0);

	if (unlikely(err))
		goto error;

	if (esp->conf.ivlen) {
		memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
		crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
	}

	if (esp->auth.icv_full_len) {
		err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
				     sizeof(*esph) + esp->conf.ivlen + clen);
		memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
	}

error:
	return err;
}

static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ipv6hdr *iph;
	struct ipv6_esp_hdr *esph;
	struct esp_data *esp = x->data;
	struct crypto_blkcipher *tfm = esp->conf.tfm;
	struct blkcipher_desc desc = { .tfm = tfm };
	struct sk_buff *trailer;
	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
	int alen = esp->auth.icv_trunc_len;
	int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
	int hdr_len = skb_network_header_len(skb);
	int nfrags;
	int ret = 0;

	if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
		ret = -EINVAL;
		goto out;
	}

	if (elen <= 0 || (elen & (blksize-1))) {
		ret = -EINVAL;
		goto out;
	}

	/* If integrity check is required, do this. */
	if (esp->auth.icv_full_len) {
		u8 sum[alen];

		ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
		if (ret)
			goto out;

		if (skb_copy_bits(skb, skb->len - alen, sum, alen))
			BUG();

		if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
			x->stats.integrity_failed++;
			ret = -EINVAL;
			goto out;
		}
	}

	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
		ret = -EINVAL;
		goto out;
	}

	skb->ip_summed = CHECKSUM_NONE;

	esph = (struct ipv6_esp_hdr*)skb->data;
	iph = ipv6_hdr(skb);

	/* Get ivec. This can be wrong, check against another impls. */
	if (esp->conf.ivlen)
		crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);

	{
		u8 nexthdr[2];
		struct scatterlist *sg = &esp->sgbuf[0];
		u8 padlen;

		if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
			sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
			if (!sg) {
				ret = -ENOMEM;
				goto out;
			}
		}
		skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
		ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
		if (unlikely(sg != &esp->sgbuf[0]))
			kfree(sg);
		if (unlikely(ret))
			goto out;

		if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
			BUG();

		padlen = nexthdr[0];
		if (padlen+2 >= elen) {
			LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
			ret = -EINVAL;
			goto out;
		}
		/* ... check padding bits here. Silly. :-) */

		pskb_trim(skb, skb->len - alen - padlen - 2);
		ret = nexthdr[1];
	}

	__skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
	skb_set_transport_header(skb, -hdr_len);
out:
	return ret;
}

static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
{
	struct esp_data *esp = x->data;
	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
	u32 align = max_t(u32, blksize, esp->conf.padlen);
	u32 rem;

	mtu -= x->props.header_len + esp->auth.icv_trunc_len;
	rem = mtu & (align - 1);
	mtu &= ~(align - 1);

	if (x->props.mode != XFRM_MODE_TUNNEL) {
		u32 padsize = ((blksize - 1) & 7) + 1;
		mtu -= blksize - padsize;
		mtu += min_t(u32, blksize - padsize, rem);
	}

	return mtu - 2;
}

static void esp6_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 ipv6_esp_hdr *esph = (struct ipv6_esp_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, esph->spi, IPPROTO_ESP, AF_INET6);
	if (!x)
		return;
	printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
			ntohl(esph->spi), NIP6(iph->daddr));
	xfrm_state_put(x);
}

static void esp6_destroy(struct xfrm_state *x)
{
	struct esp_data *esp = x->data;

	if (!esp)
		return;

	crypto_free_blkcipher(esp->conf.tfm);
	esp->conf.tfm = NULL;
	kfree(esp->conf.ivec);
	esp->conf.ivec = NULL;
	crypto_free_hash(esp->auth.tfm);
	esp->auth.tfm = NULL;
	kfree(esp->auth.work_icv);
	esp->auth.work_icv = NULL;
	kfree(esp);
}

static int esp6_init_state(struct xfrm_state *x)
{
	struct esp_data *esp = NULL;
	struct crypto_blkcipher *tfm;

	/* null auth and encryption can have zero length keys */
	if (x->aalg) {
		if (x->aalg->alg_key_len > 512)
			goto error;
	}
	if (x->ealg == NULL)
		goto error;

	if (x->encap)
		goto error;

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

	if (x->aalg) {
		struct xfrm_algo_desc *aalg_desc;
		struct crypto_hash *hash;

		esp->auth.key = x->aalg->alg_key;
		esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
		hash = crypto_alloc_hash(x->aalg->alg_name, 0,
					 CRYPTO_ALG_ASYNC);
		if (IS_ERR(hash))
			goto error;

		esp->auth.tfm = hash;
		if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
			goto error;

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

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

		esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
		if (!esp->auth.work_icv)
			goto error;
	}
	esp->conf.key = x->ealg->alg_key;
	esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
	tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm))
		goto error;
	esp->conf.tfm = tfm;
	esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
	esp->conf.padlen = 0;
	if (esp->conf.ivlen) {
		esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
		if (unlikely(esp->conf.ivec == NULL))
			goto error;
		esp->conf.ivinitted = 0;
	}
	if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
		goto error;
	x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct ipv6hdr);
	x->data = esp;
	return 0;

error:
	x->data = esp;
	esp6_destroy(x);
	x->data = NULL;
	return -EINVAL;
}

static struct xfrm_type esp6_type =
{
	.description	= "ESP6",
	.owner	     	= THIS_MODULE,
	.proto	     	= IPPROTO_ESP,
	.init_state	= esp6_init_state,
	.destructor	= esp6_destroy,
	.get_mtu	= esp6_get_mtu,
	.input		= esp6_input,
	.output		= esp6_output,
	.hdr_offset	= xfrm6_find_1stfragopt,
};

static struct inet6_protocol esp6_protocol = {
	.handler 	=	xfrm6_rcv,
	.err_handler	=	esp6_err,
	.flags		=	INET6_PROTO_NOPOLICY,
};

static int __init esp6_init(void)
{
	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
		printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
		printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
		xfrm_unregister_type(&esp6_type, AF_INET6);
		return -EAGAIN;
	}

	return 0;
}

static void __exit esp6_fini(void)
{
	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
		printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
		printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
}

module_init(esp6_init);
module_exit(esp6_fini);

MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
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/esp.c
	25	*/
	26
6b7326c8	27	#include <linux/err.h>
1da177e4 LT	28	#include <linux/module.h>
	29	#include <net/ip.h>
	30	#include <net/xfrm.h>
	31	#include <net/esp.h>
	32	#include <asm/scatterlist.h>
	33	#include <linux/crypto.h>
a02a6422	34	#include <linux/kernel.h>
1da177e4 LT	35	#include <linux/pfkeyv2.h>
	36	#include <linux/random.h>
	37	#include <net/icmp.h>
	38	#include <net/ipv6.h>
14c85021	39	#include <net/protocol.h>
1da177e4 LT	40	#include <linux/icmpv6.h>
	41
	42	static int esp6_output(struct xfrm_state x, struct sk_buff skb)
	43	{
	44	int err;
1da177e4 LT	45	struct ipv6hdr *top_iph;
1da177e4 LT	46	struct ipv6_esp_hdr *esph;
6b7326c8 HX	47	struct crypto_blkcipher *tfm;
6b7326c8 HX	48	struct blkcipher_desc desc;
1da177e4 LT	49	struct sk_buff *trailer;
	50	int blksize;
	51	int clen;
	52	int alen;
	53	int nfrags;
27a884dc	54	u8 *tail;
ea2ae17d ACM	55	struct esp_data *esp = x->data;
	56	int hdr_len = (skb_transport_offset(skb) +
	57	sizeof(*esph) + esp->conf.ivlen);
1da177e4 LT	58
	59	/* Strip IP+ESP header. */
	60	__skb_pull(skb, hdr_len);
	61
	62	/* Now skb is pure payload to encrypt */
	63	err = -ENOMEM;
	64
	65	/* Round to block size */
	66	clen = skb->len;
	67
	68	alen = esp->auth.icv_trunc_len;
	69	tfm = esp->conf.tfm;
6b7326c8 HX	70	desc.tfm = tfm;
	71	desc.flags = 0;
	72	blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
a02a6422	73	clen = ALIGN(clen + 2, blksize);
1da177e4	74	if (esp->conf.padlen)
a02a6422	75	clen = ALIGN(clen, esp->conf.padlen);
1da177e4 LT	76
	77	if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
	78	goto error;
	79	}
	80
	81	/* Fill padding... */
27a884dc	82	tail = skb_tail_pointer(trailer);
1da177e4 LT	83	do {
	84	int i;
	85	for (i=0; i<clen-skb->len - 2; i++)
27a884dc	86	tail[i] = i + 1;
1da177e4	87	} while (0);
27a884dc	88	tail[clen-skb->len - 2] = (clen - skb->len) - 2;
1da177e4 LT	89	pskb_put(skb, trailer, clen - skb->len);
	90
	91	top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
9c70220b	92	esph = (struct ipv6_esp_hdr *)skb_transport_header(skb);
1da177e4	93	top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
55792258	94	(skb_tail_pointer(trailer) - 1) = skb_network_header(skb);
d56f90a7	95	*skb_network_header(skb) = IPPROTO_ESP;
1da177e4 LT	96
	97	esph->spi = x->id.spi;
	98	esph->seq_no = htonl(++x->replay.oseq);
9500e8a8	99	xfrm_aevent_doreplay(x);
1da177e4	100
e4bec827 DM	101	if (esp->conf.ivlen) {
	102	if (unlikely(!esp->conf.ivinitted)) {
	103	get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
	104	esp->conf.ivinitted = 1;
	105	}
6b7326c8	106	crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
e4bec827	107	}
1da177e4 LT	108
	109	do {
	110	struct scatterlist *sg = &esp->sgbuf[0];
	111
	112	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	113	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	114	if (!sg)
	115	goto error;
	116	}
	117	skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
6b7326c8	118	err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
1da177e4 LT	119	if (unlikely(sg != &esp->sgbuf[0]))
	120	kfree(sg);
	121	} while (0);
	122
6b7326c8 HX	123	if (unlikely(err))
	124	goto error;
	125
1da177e4	126	if (esp->conf.ivlen) {
6b7326c8 HX	127	memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
6b7326c8 HX	128	crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
1da177e4 LT	129	}
	130
	131	if (esp->auth.icv_full_len) {
07d4ee58 HX	132	err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
	133	sizeof(*esph) + esp->conf.ivlen + clen);
	134	memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
1da177e4 LT	135	}
1da177e4 LT	136
1da177e4 LT	137	error:
	138	return err;
	139	}
	140
e695633e	141	static int esp6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	142	{
	143	struct ipv6hdr *iph;
	144	struct ipv6_esp_hdr *esph;
	145	struct esp_data *esp = x->data;
6b7326c8 HX	146	struct crypto_blkcipher *tfm = esp->conf.tfm;
6b7326c8 HX	147	struct blkcipher_desc desc = { .tfm = tfm };
1da177e4	148	struct sk_buff *trailer;
6b7326c8	149	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
1da177e4 LT	150	int alen = esp->auth.icv_trunc_len;
1da177e4 LT	151	int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
cfe1fc77	152	int hdr_len = skb_network_header_len(skb);
1da177e4	153	int nfrags;
1da177e4 LT	154	int ret = 0;
	155
	156	if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
	157	ret = -EINVAL;
31a4ab93	158	goto out;
1da177e4 LT	159	}
	160
	161	if (elen <= 0 \|\| (elen & (blksize-1))) {
	162	ret = -EINVAL;
31a4ab93	163	goto out;
1da177e4	164	}
1da177e4 LT	165
1da177e4 LT	166	/* If integrity check is required, do this. */
1ab1457c	167	if (esp->auth.icv_full_len) {
07d4ee58	168	u8 sum[alen];
1da177e4	169
07d4ee58 HX	170	ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
	171	if (ret)
	172	goto out;
1da177e4	173
07d4ee58	174	if (skb_copy_bits(skb, skb->len - alen, sum, alen))
1da177e4 LT	175	BUG();
1da177e4 LT	176
07d4ee58	177	if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
1da177e4 LT	178	x->stats.integrity_failed++;
	179	ret = -EINVAL;
	180	goto out;
	181	}
	182	}
	183
	184	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
	185	ret = -EINVAL;
	186	goto out;
	187	}
	188
	189	skb->ip_summed = CHECKSUM_NONE;
	190
	191	esph = (struct ipv6_esp_hdr*)skb->data;
0660e03f	192	iph = ipv6_hdr(skb);
1da177e4 LT	193
	194	/* Get ivec. This can be wrong, check against another impls. */
	195	if (esp->conf.ivlen)
6b7326c8	196	crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
1da177e4	197
1ab1457c	198	{
1da177e4 LT	199	u8 nexthdr[2];
	200	struct scatterlist *sg = &esp->sgbuf[0];
	201	u8 padlen;
	202
	203	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	204	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	205	if (!sg) {
	206	ret = -ENOMEM;
	207	goto out;
	208	}
	209	}
	210	skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
6b7326c8	211	ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
1da177e4 LT	212	if (unlikely(sg != &esp->sgbuf[0]))
1da177e4 LT	213	kfree(sg);
6b7326c8 HX	214	if (unlikely(ret))
6b7326c8 HX	215	goto out;
1da177e4 LT	216
	217	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
	218	BUG();
	219
	220	padlen = nexthdr[0];
	221	if (padlen+2 >= elen) {
64ce2073	222	LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
1da177e4 LT	223	ret = -EINVAL;
	224	goto out;
	225	}
1ab1457c	226	/* ... check padding bits here. Silly. :-) */
1da177e4 LT	227
1da177e4 LT	228	pskb_trim(skb, skb->len - alen - padlen - 2);
1da177e4 LT	229	ret = nexthdr[1];
	230	}
	231
967b05f6 ACM	232	__skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
967b05f6 ACM	233	skb_set_transport_header(skb, -hdr_len);
1da177e4	234	out:
1da177e4 LT	235	return ret;
	236	}
	237
c5c25238	238	static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
1da177e4 LT	239	{
1da177e4 LT	240	struct esp_data *esp = x->data;
6b7326c8	241	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
c5c25238 PM	242	u32 align = max_t(u32, blksize, esp->conf.padlen);
c5c25238 PM	243	u32 rem;
1da177e4	244
c5c25238 PM	245	mtu -= x->props.header_len + esp->auth.icv_trunc_len;
	246	rem = mtu & (align - 1);
	247	mtu &= ~(align - 1);
	248
	249	if (x->props.mode != XFRM_MODE_TUNNEL) {
d4875b04	250	u32 padsize = ((blksize - 1) & 7) + 1;
c5c25238 PM	251	mtu -= blksize - padsize;
c5c25238 PM	252	mtu += min_t(u32, blksize - padsize, rem);
1da177e4	253	}
1da177e4	254
c5c25238	255	return mtu - 2;
1da177e4 LT	256	}
	257
	258	static void esp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
1ab1457c	259	int type, int code, int offset, __be32 info)
1da177e4 LT	260	{
	261	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	262	struct ipv6_esp_hdr esph = (struct ipv6_esp_hdr)(skb->data+offset);
	263	struct xfrm_state *x;
	264
1ab1457c	265	if (type != ICMPV6_DEST_UNREACH &&
1da177e4 LT	266	type != ICMPV6_PKT_TOOBIG)
	267	return;
	268
	269	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
	270	if (!x)
	271	return;
1ab1457c	272	printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
1da177e4 LT	273	ntohl(esph->spi), NIP6(iph->daddr));
	274	xfrm_state_put(x);
	275	}
	276
	277	static void esp6_destroy(struct xfrm_state *x)
	278	{
	279	struct esp_data *esp = x->data;
	280
	281	if (!esp)
	282	return;
	283
6b7326c8	284	crypto_free_blkcipher(esp->conf.tfm);
573dbd95 JJ	285	esp->conf.tfm = NULL;
	286	kfree(esp->conf.ivec);
	287	esp->conf.ivec = NULL;
07d4ee58	288	crypto_free_hash(esp->auth.tfm);
573dbd95 JJ	289	esp->auth.tfm = NULL;
	290	kfree(esp->auth.work_icv);
	291	esp->auth.work_icv = NULL;
1da177e4 LT	292	kfree(esp);
	293	}
	294
72cb6962	295	static int esp6_init_state(struct xfrm_state *x)
1da177e4 LT	296	{
1da177e4 LT	297	struct esp_data *esp = NULL;
6b7326c8	298	struct crypto_blkcipher *tfm;
1da177e4 LT	299
	300	/* null auth and encryption can have zero length keys */
	301	if (x->aalg) {
	302	if (x->aalg->alg_key_len > 512)
	303	goto error;
	304	}
	305	if (x->ealg == NULL)
	306	goto error;
	307
	308	if (x->encap)
	309	goto error;
	310
0c600eda	311	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
1da177e4 LT	312	if (esp == NULL)
	313	return -ENOMEM;
	314
1da177e4 LT	315	if (x->aalg) {
1da177e4 LT	316	struct xfrm_algo_desc *aalg_desc;
07d4ee58	317	struct crypto_hash *hash;
1da177e4 LT	318
	319	esp->auth.key = x->aalg->alg_key;
	320	esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
07d4ee58 HX	321	hash = crypto_alloc_hash(x->aalg->alg_name, 0,
	322	CRYPTO_ALG_ASYNC);
	323	if (IS_ERR(hash))
	324	goto error;
	325
	326	esp->auth.tfm = hash;
	327	if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
1da177e4	328	goto error;
1ab1457c	329
1da177e4 LT	330	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1da177e4 LT	331	BUG_ON(!aalg_desc);
1ab1457c	332
1da177e4	333	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58 HX	334	crypto_hash_digestsize(hash)) {
	335	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
	336	x->aalg->alg_name,
	337	crypto_hash_digestsize(hash),
	338	aalg_desc->uinfo.auth.icv_fullbits/8);
	339	goto error;
1da177e4	340	}
1ab1457c	341
1da177e4 LT	342	esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
1da177e4 LT	343	esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
1ab1457c	344
1da177e4 LT	345	esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
	346	if (!esp->auth.work_icv)
	347	goto error;
	348	}
	349	esp->conf.key = x->ealg->alg_key;
	350	esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
6b7326c8 HX	351	tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
6b7326c8 HX	352	if (IS_ERR(tfm))
1da177e4	353	goto error;
6b7326c8 HX	354	esp->conf.tfm = tfm;
6b7326c8 HX	355	esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
1da177e4 LT	356	esp->conf.padlen = 0;
	357	if (esp->conf.ivlen) {
	358	esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
	359	if (unlikely(esp->conf.ivec == NULL))
	360	goto error;
e4bec827	361	esp->conf.ivinitted = 0;
1da177e4	362	}
6b7326c8	363	if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
1da177e4 LT	364	goto error;
1da177e4 LT	365	x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
7e49e6de	366	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	367	x->props.header_len += sizeof(struct ipv6hdr);
	368	x->data = esp;
	369	return 0;
	370
	371	error:
	372	x->data = esp;
	373	esp6_destroy(x);
	374	x->data = NULL;
	375	return -EINVAL;
	376	}
	377
	378	static struct xfrm_type esp6_type =
	379	{
	380	.description = "ESP6",
	381	.owner = THIS_MODULE,
	382	.proto = IPPROTO_ESP,
	383	.init_state = esp6_init_state,
	384	.destructor = esp6_destroy,
c5c25238	385	.get_mtu = esp6_get_mtu,
1da177e4	386	.input = esp6_input,
aee5adb4 MN	387	.output = esp6_output,
aee5adb4 MN	388	.hdr_offset = xfrm6_find_1stfragopt,
1da177e4 LT	389	};
	390
	391	static struct inet6_protocol esp6_protocol = {
	392	.handler = xfrm6_rcv,
	393	.err_handler = esp6_err,
	394	.flags = INET6_PROTO_NOPOLICY,
	395	};
	396
	397	static int __init esp6_init(void)
	398	{
	399	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
	400	printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
	401	return -EAGAIN;
	402	}
	403	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
	404	printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
	405	xfrm_unregister_type(&esp6_type, AF_INET6);
	406	return -EAGAIN;
	407	}
	408
	409	return 0;
	410	}
	411
	412	static void __exit esp6_fini(void)
	413	{
	414	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
	415	printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
	416	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
	417	printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
	418	}
	419
	420	module_init(esp6_init);
	421	module_exit(esp6_fini);
	422
	423	MODULE_LICENSE("GPL");
d3d6dd3a	424	MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);