[mirror_ubuntu-bionic-kernel.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 <kunihiro@ipinfusion.com>
 *
 * 	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 <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/random.h>
#include <linux/spinlock.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 ip_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;

	/* 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);

	skb_push(skb, -skb_network_offset(skb));
	esph = ip_esp_hdr(skb);
	*(skb_tail_pointer(trailer) - 1) = *skb_mac_header(skb);
	*skb_mac_header(skb) = IPPROTO_ESP;

	esph->spi = x->id.spi;
	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);

	spin_lock_bh(&x->lock);

	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 unlock;
		}
		sg_init_table(sg, nfrags);
		sg_mark_end(sg, 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 unlock;

	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);
	}

unlock:
	spin_unlock_bh(&x->lock);

error:
	return err;
}

static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ipv6hdr *iph;
	struct ip_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(*esph) - esp->conf.ivlen - alen;
	int hdr_len = skb_network_header_len(skb);
	int nfrags;
	int ret = 0;

	if (!pskb_may_pull(skb, sizeof(*esph))) {
		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 ip_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;
			}
		}
		sg_init_table(sg, nfrags);
		sg_mark_end(sg, skb_to_sgvec(skb, sg,
					     sizeof(*esph) + 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 ip_esp_hdr *esph = (struct ip_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;

	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;

		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, x->aalg->alg_key,
				       (x->aalg->alg_key_len + 7) / 8))
			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;
	}
	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, x->ealg->alg_key,
				    (x->ealg->alg_key_len + 7) / 8))
		goto error;
	x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
	switch (x->props.mode) {
	case XFRM_MODE_BEET:
	case XFRM_MODE_TRANSPORT:
		break;
	case XFRM_MODE_TUNNEL:
		x->props.header_len += sizeof(struct ipv6hdr);
		break;
	default:
		goto error;
	}
	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,
	.flags		= XFRM_TYPE_REPLAY_PROT,
	.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 <kunihiro@ipinfusion.com>
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>
72998d8c	32	#include <linux/scatterlist.h>
1da177e4	33	#include <linux/crypto.h>
a02a6422	34	#include <linux/kernel.h>
1da177e4 LT	35	#include <linux/pfkeyv2.h>
1da177e4 LT	36	#include <linux/random.h>
b7c6538c	37	#include <linux/spinlock.h>
1da177e4 LT	38	#include <net/icmp.h>
1da177e4 LT	39	#include <net/ipv6.h>
14c85021	40	#include <net/protocol.h>
1da177e4 LT	41	#include <linux/icmpv6.h>
	42
	43	static int esp6_output(struct xfrm_state x, struct sk_buff skb)
	44	{
	45	int err;
87bdc48d	46	struct ip_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	55	struct esp_data *esp = x->data;
1da177e4	56
7b277b1a	57	/* skb is pure payload to encrypt */
1da177e4 LT	58	err = -ENOMEM;
	59
	60	/* Round to block size */
	61	clen = skb->len;
	62
	63	alen = esp->auth.icv_trunc_len;
	64	tfm = esp->conf.tfm;
6b7326c8 HX	65	desc.tfm = tfm;
	66	desc.flags = 0;
	67	blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
a02a6422	68	clen = ALIGN(clen + 2, blksize);
1da177e4	69	if (esp->conf.padlen)
a02a6422	70	clen = ALIGN(clen, esp->conf.padlen);
1da177e4 LT	71
	72	if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
	73	goto error;
	74	}
	75
	76	/* Fill padding... */
27a884dc	77	tail = skb_tail_pointer(trailer);
1da177e4 LT	78	do {
	79	int i;
	80	for (i=0; i<clen-skb->len - 2; i++)
27a884dc	81	tail[i] = i + 1;
1da177e4	82	} while (0);
27a884dc	83	tail[clen-skb->len - 2] = (clen - skb->len) - 2;
1da177e4 LT	84	pskb_put(skb, trailer, clen - skb->len);
1da177e4 LT	85
7b277b1a	86	skb_push(skb, -skb_network_offset(skb));
87bdc48d	87	esph = ip_esp_hdr(skb);
007f0211 HX	88	(skb_tail_pointer(trailer) - 1) = skb_mac_header(skb);
007f0211 HX	89	*skb_mac_header(skb) = IPPROTO_ESP;
1da177e4 LT	90
1da177e4 LT	91	esph->spi = x->id.spi;
436a0a40	92	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
1da177e4	93
b7c6538c HX	94	spin_lock_bh(&x->lock);
b7c6538c HX	95
e4bec827 DM	96	if (esp->conf.ivlen) {
	97	if (unlikely(!esp->conf.ivinitted)) {
	98	get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
	99	esp->conf.ivinitted = 1;
	100	}
6b7326c8	101	crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
e4bec827	102	}
1da177e4 LT	103
	104	do {
	105	struct scatterlist *sg = &esp->sgbuf[0];
	106
	107	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	108	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	109	if (!sg)
b7c6538c	110	goto unlock;
1da177e4	111	}
ed0e7e0c	112	sg_init_table(sg, nfrags);
68e3f5dd HX	113	sg_mark_end(sg, skb_to_sgvec(skb, sg, esph->enc_data +
	114	esp->conf.ivlen -
	115	skb->data, clen));
6b7326c8	116	err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
1da177e4 LT	117	if (unlikely(sg != &esp->sgbuf[0]))
	118	kfree(sg);
	119	} while (0);
	120
6b7326c8	121	if (unlikely(err))
b7c6538c	122	goto unlock;
6b7326c8	123
1da177e4	124	if (esp->conf.ivlen) {
6b7326c8 HX	125	memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
6b7326c8 HX	126	crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
1da177e4 LT	127	}
	128
	129	if (esp->auth.icv_full_len) {
07d4ee58 HX	130	err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
	131	sizeof(*esph) + esp->conf.ivlen + clen);
	132	memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
1da177e4 LT	133	}
1da177e4 LT	134
b7c6538c HX	135	unlock:
	136	spin_unlock_bh(&x->lock);
	137
1da177e4 LT	138	error:
	139	return err;
	140	}
	141
e695633e	142	static int esp6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	143	{
1da177e4 LT	144	struct ipv6hdr *iph;
87bdc48d	145	struct ip_esp_hdr *esph;
1da177e4	146	struct esp_data *esp = x->data;
6b7326c8 HX	147	struct crypto_blkcipher *tfm = esp->conf.tfm;
6b7326c8 HX	148	struct blkcipher_desc desc = { .tfm = tfm };
1da177e4	149	struct sk_buff *trailer;
6b7326c8	150	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
1da177e4	151	int alen = esp->auth.icv_trunc_len;
87bdc48d	152	int elen = skb->len - sizeof(*esph) - esp->conf.ivlen - alen;
cfe1fc77	153	int hdr_len = skb_network_header_len(skb);
1da177e4	154	int nfrags;
1da177e4 LT	155	int ret = 0;
1da177e4 LT	156
87bdc48d	157	if (!pskb_may_pull(skb, sizeof(*esph))) {
1da177e4	158	ret = -EINVAL;
31a4ab93	159	goto out;
1da177e4 LT	160	}
	161
	162	if (elen <= 0 \|\| (elen & (blksize-1))) {
	163	ret = -EINVAL;
31a4ab93	164	goto out;
1da177e4	165	}
1da177e4 LT	166
1da177e4 LT	167	/* If integrity check is required, do this. */
1ab1457c	168	if (esp->auth.icv_full_len) {
07d4ee58	169	u8 sum[alen];
1da177e4	170
07d4ee58 HX	171	ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
	172	if (ret)
	173	goto out;
1da177e4	174
07d4ee58	175	if (skb_copy_bits(skb, skb->len - alen, sum, alen))
1da177e4 LT	176	BUG();
1da177e4 LT	177
07d4ee58	178	if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
1da177e4 LT	179	x->stats.integrity_failed++;
	180	ret = -EINVAL;
	181	goto out;
	182	}
	183	}
	184
	185	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
	186	ret = -EINVAL;
	187	goto out;
	188	}
	189
	190	skb->ip_summed = CHECKSUM_NONE;
	191
87bdc48d	192	esph = (struct ip_esp_hdr *)skb->data;
0660e03f	193	iph = ipv6_hdr(skb);
1da177e4 LT	194
	195	/* Get ivec. This can be wrong, check against another impls. */
	196	if (esp->conf.ivlen)
6b7326c8	197	crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
1da177e4	198
1ab1457c	199	{
1da177e4 LT	200	u8 nexthdr[2];
	201	struct scatterlist *sg = &esp->sgbuf[0];
	202	u8 padlen;
	203
	204	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	205	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	206	if (!sg) {
	207	ret = -ENOMEM;
	208	goto out;
	209	}
	210	}
ed0e7e0c	211	sg_init_table(sg, nfrags);
68e3f5dd HX	212	sg_mark_end(sg, skb_to_sgvec(skb, sg,
	213	sizeof(*esph) + esp->conf.ivlen,
	214	elen));
6b7326c8	215	ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
1da177e4 LT	216	if (unlikely(sg != &esp->sgbuf[0]))
1da177e4 LT	217	kfree(sg);
6b7326c8 HX	218	if (unlikely(ret))
6b7326c8 HX	219	goto out;
1da177e4 LT	220
	221	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
	222	BUG();
	223
	224	padlen = nexthdr[0];
	225	if (padlen+2 >= elen) {
64ce2073	226	LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
1da177e4 LT	227	ret = -EINVAL;
	228	goto out;
	229	}
1ab1457c	230	/* ... check padding bits here. Silly. :-) */
1da177e4 LT	231
1da177e4 LT	232	pskb_trim(skb, skb->len - alen - padlen - 2);
1da177e4 LT	233	ret = nexthdr[1];
	234	}
	235
967b05f6 ACM	236	__skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
967b05f6 ACM	237	skb_set_transport_header(skb, -hdr_len);
1da177e4	238	out:
1da177e4 LT	239	return ret;
	240	}
	241
c5c25238	242	static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
1da177e4 LT	243	{
1da177e4 LT	244	struct esp_data *esp = x->data;
6b7326c8	245	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
c5c25238 PM	246	u32 align = max_t(u32, blksize, esp->conf.padlen);
c5c25238 PM	247	u32 rem;
1da177e4	248
c5c25238 PM	249	mtu -= x->props.header_len + esp->auth.icv_trunc_len;
	250	rem = mtu & (align - 1);
	251	mtu &= ~(align - 1);
	252
	253	if (x->props.mode != XFRM_MODE_TUNNEL) {
d4875b04	254	u32 padsize = ((blksize - 1) & 7) + 1;
c5c25238 PM	255	mtu -= blksize - padsize;
c5c25238 PM	256	mtu += min_t(u32, blksize - padsize, rem);
1da177e4	257	}
1da177e4	258
c5c25238	259	return mtu - 2;
1da177e4 LT	260	}
	261
	262	static void esp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
1ab1457c	263	int type, int code, int offset, __be32 info)
1da177e4 LT	264	{
1da177e4 LT	265	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
87bdc48d	266	struct ip_esp_hdr esph = (struct ip_esp_hdr )(skb->data + offset);
1da177e4 LT	267	struct xfrm_state *x;
1da177e4 LT	268
1ab1457c	269	if (type != ICMPV6_DEST_UNREACH &&
1da177e4 LT	270	type != ICMPV6_PKT_TOOBIG)
	271	return;
	272
	273	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
	274	if (!x)
	275	return;
1ab1457c	276	printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
1da177e4 LT	277	ntohl(esph->spi), NIP6(iph->daddr));
	278	xfrm_state_put(x);
	279	}
	280
	281	static void esp6_destroy(struct xfrm_state *x)
	282	{
	283	struct esp_data *esp = x->data;
	284
	285	if (!esp)
	286	return;
	287
6b7326c8	288	crypto_free_blkcipher(esp->conf.tfm);
573dbd95 JJ	289	esp->conf.tfm = NULL;
	290	kfree(esp->conf.ivec);
	291	esp->conf.ivec = NULL;
07d4ee58	292	crypto_free_hash(esp->auth.tfm);
573dbd95 JJ	293	esp->auth.tfm = NULL;
	294	kfree(esp->auth.work_icv);
	295	esp->auth.work_icv = NULL;
1da177e4 LT	296	kfree(esp);
	297	}
	298
72cb6962	299	static int esp6_init_state(struct xfrm_state *x)
1da177e4 LT	300	{
1da177e4 LT	301	struct esp_data *esp = NULL;
6b7326c8	302	struct crypto_blkcipher *tfm;
1da177e4	303
1da177e4 LT	304	if (x->ealg == NULL)
	305	goto error;
	306
	307	if (x->encap)
	308	goto error;
	309
0c600eda	310	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
1da177e4 LT	311	if (esp == NULL)
	312	return -ENOMEM;
	313
1da177e4 LT	314	if (x->aalg) {
1da177e4 LT	315	struct xfrm_algo_desc *aalg_desc;
07d4ee58	316	struct crypto_hash *hash;
1da177e4	317
07d4ee58 HX	318	hash = crypto_alloc_hash(x->aalg->alg_name, 0,
	319	CRYPTO_ALG_ASYNC);
	320	if (IS_ERR(hash))
	321	goto error;
	322
	323	esp->auth.tfm = hash;
4b7137ff HX	324	if (crypto_hash_setkey(hash, x->aalg->alg_key,
4b7137ff HX	325	(x->aalg->alg_key_len + 7) / 8))
1da177e4	326	goto error;
1ab1457c	327
1da177e4 LT	328	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1da177e4 LT	329	BUG_ON(!aalg_desc);
1ab1457c	330
1da177e4	331	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58 HX	332	crypto_hash_digestsize(hash)) {
	333	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
	334	x->aalg->alg_name,
	335	crypto_hash_digestsize(hash),
	336	aalg_desc->uinfo.auth.icv_fullbits/8);
	337	goto error;
1da177e4	338	}
1ab1457c	339
1da177e4 LT	340	esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
1da177e4 LT	341	esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
1ab1457c	342
1da177e4 LT	343	esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
	344	if (!esp->auth.work_icv)
	345	goto error;
	346	}
6b7326c8 HX	347	tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
6b7326c8 HX	348	if (IS_ERR(tfm))
1da177e4	349	goto error;
6b7326c8 HX	350	esp->conf.tfm = tfm;
6b7326c8 HX	351	esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
1da177e4 LT	352	esp->conf.padlen = 0;
	353	if (esp->conf.ivlen) {
	354	esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
	355	if (unlikely(esp->conf.ivec == NULL))
	356	goto error;
e4bec827	357	esp->conf.ivinitted = 0;
1da177e4	358	}
4b7137ff HX	359	if (crypto_blkcipher_setkey(tfm, x->ealg->alg_key,
4b7137ff HX	360	(x->ealg->alg_key_len + 7) / 8))
1da177e4	361	goto error;
87bdc48d	362	x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
ca68145f HX	363	switch (x->props.mode) {
	364	case XFRM_MODE_BEET:
	365	case XFRM_MODE_TRANSPORT:
	366	break;
	367	case XFRM_MODE_TUNNEL:
1da177e4	368	x->props.header_len += sizeof(struct ipv6hdr);
ea2c47b4	369	break;
ca68145f HX	370	default:
	371	goto error;
	372	}
1da177e4 LT	373	x->data = esp;
	374	return 0;
	375
	376	error:
	377	x->data = esp;
	378	esp6_destroy(x);
	379	x->data = NULL;
	380	return -EINVAL;
	381	}
	382
	383	static struct xfrm_type esp6_type =
	384	{
	385	.description = "ESP6",
	386	.owner = THIS_MODULE,
	387	.proto = IPPROTO_ESP,
436a0a40	388	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	389	.init_state = esp6_init_state,
1da177e4 LT	390	.destructor = esp6_destroy,
c5c25238	391	.get_mtu = esp6_get_mtu,
1da177e4	392	.input = esp6_input,
aee5adb4 MN	393	.output = esp6_output,
aee5adb4 MN	394	.hdr_offset = xfrm6_find_1stfragopt,
1da177e4 LT	395	};
	396
	397	static struct inet6_protocol esp6_protocol = {
	398	.handler = xfrm6_rcv,
	399	.err_handler = esp6_err,
	400	.flags = INET6_PROTO_NOPOLICY,
	401	};
	402
	403	static int __init esp6_init(void)
	404	{
	405	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
	406	printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
	407	return -EAGAIN;
	408	}
	409	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
	410	printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
	411	xfrm_unregister_type(&esp6_type, AF_INET6);
	412	return -EAGAIN;
	413	}
	414
	415	return 0;
	416	}
	417
	418	static void __exit esp6_fini(void)
	419	{
	420	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
	421	printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
	422	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
	423	printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
	424	}
	425
	426	module_init(esp6_init);
	427	module_exit(esp6_fini);
	428
	429	MODULE_LICENSE("GPL");
d3d6dd3a	430	MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);