[deliverable/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 <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 <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;
	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... */
	do {
		int i;
		for (i=0; i<clen-skb->len - 2; i++)
			*(u8*)(trailer->tail + i) = i+1;
	} while (0);
	*(u8*)(trailer->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->h.raw;
	top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
	*(u8 *)(trailer->tail - 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->h.raw - skb->nh.raw;
	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->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;

out:
	return ret;
}

static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
{
	struct esp_data *esp = x->data;
	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);

	if (x->props.mode == XFRM_MODE_TUNNEL) {
		mtu = ALIGN(mtu + 2, blksize);
	} else {
		/* The worst case. */
		u32 padsize = ((blksize - 1) & 7) + 1;
		mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
	}
	if (esp->conf.padlen)
		mtu = ALIGN(mtu, esp->conf.padlen);

	return mtu + x->props.header_len + esp->auth.icv_trunc_len;
}

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_max_size	= esp6_get_max_size,
	.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");
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>
	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;
ea2ae17d ACM	54	struct esp_data *esp = x->data;
	55	int hdr_len = (skb_transport_offset(skb) +
	56	sizeof(*esph) + esp->conf.ivlen);
1da177e4 LT	57
	58	/* Strip IP+ESP header. */
	59	__skb_pull(skb, hdr_len);
	60
	61	/* Now skb is pure payload to encrypt */
	62	err = -ENOMEM;
	63
	64	/* Round to block size */
	65	clen = skb->len;
	66
	67	alen = esp->auth.icv_trunc_len;
	68	tfm = esp->conf.tfm;
6b7326c8 HX	69	desc.tfm = tfm;
	70	desc.flags = 0;
	71	blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
a02a6422	72	clen = ALIGN(clen + 2, blksize);
1da177e4	73	if (esp->conf.padlen)
a02a6422	74	clen = ALIGN(clen, esp->conf.padlen);
1da177e4 LT	75
	76	if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
	77	goto error;
	78	}
	79
	80	/* Fill padding... */
	81	do {
	82	int i;
	83	for (i=0; i<clen-skb->len - 2; i++)
	84	(u8)(trailer->tail + i) = i+1;
	85	} while (0);
	86	(u8)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
	87	pskb_put(skb, trailer, clen - skb->len);
	88
	89	top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
	90	esph = (struct ipv6_esp_hdr *)skb->h.raw;
	91	top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
d56f90a7 ACM	92	(u8 )(trailer->tail - 1) = *skb_network_header(skb);
d56f90a7 ACM	93	*skb_network_header(skb) = IPPROTO_ESP;
1da177e4 LT	94
	95	esph->spi = x->id.spi;
	96	esph->seq_no = htonl(++x->replay.oseq);
9500e8a8	97	xfrm_aevent_doreplay(x);
1da177e4	98
e4bec827 DM	99	if (esp->conf.ivlen) {
	100	if (unlikely(!esp->conf.ivinitted)) {
	101	get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
	102	esp->conf.ivinitted = 1;
	103	}
6b7326c8	104	crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
e4bec827	105	}
1da177e4 LT	106
	107	do {
	108	struct scatterlist *sg = &esp->sgbuf[0];
	109
	110	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	111	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	112	if (!sg)
	113	goto error;
	114	}
	115	skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-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 HX	121	if (unlikely(err))
	122	goto error;
	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
1da177e4 LT	135	error:
	136	return err;
	137	}
	138
e695633e	139	static int esp6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	140	{
	141	struct ipv6hdr *iph;
	142	struct ipv6_esp_hdr *esph;
	143	struct esp_data *esp = x->data;
6b7326c8 HX	144	struct crypto_blkcipher *tfm = esp->conf.tfm;
6b7326c8 HX	145	struct blkcipher_desc desc = { .tfm = tfm };
1da177e4	146	struct sk_buff *trailer;
6b7326c8	147	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
1da177e4 LT	148	int alen = esp->auth.icv_trunc_len;
	149	int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
	150
	151	int hdr_len = skb->h.raw - skb->nh.raw;
	152	int nfrags;
1da177e4 LT	153	int ret = 0;
	154
	155	if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
	156	ret = -EINVAL;
31a4ab93	157	goto out;
1da177e4 LT	158	}
	159
	160	if (elen <= 0 \|\| (elen & (blksize-1))) {
	161	ret = -EINVAL;
31a4ab93	162	goto out;
1da177e4	163	}
1da177e4 LT	164
1da177e4 LT	165	/* If integrity check is required, do this. */
1ab1457c	166	if (esp->auth.icv_full_len) {
07d4ee58	167	u8 sum[alen];
1da177e4	168
07d4ee58 HX	169	ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
	170	if (ret)
	171	goto out;
1da177e4	172
07d4ee58	173	if (skb_copy_bits(skb, skb->len - alen, sum, alen))
1da177e4 LT	174	BUG();
1da177e4 LT	175
07d4ee58	176	if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
1da177e4 LT	177	x->stats.integrity_failed++;
	178	ret = -EINVAL;
	179	goto out;
	180	}
	181	}
	182
	183	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
	184	ret = -EINVAL;
	185	goto out;
	186	}
	187
	188	skb->ip_summed = CHECKSUM_NONE;
	189
	190	esph = (struct ipv6_esp_hdr*)skb->data;
0660e03f	191	iph = ipv6_hdr(skb);
1da177e4 LT	192
	193	/* Get ivec. This can be wrong, check against another impls. */
	194	if (esp->conf.ivlen)
6b7326c8	195	crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
1da177e4	196
1ab1457c	197	{
1da177e4 LT	198	u8 nexthdr[2];
	199	struct scatterlist *sg = &esp->sgbuf[0];
	200	u8 padlen;
	201
	202	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	203	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	204	if (!sg) {
	205	ret = -ENOMEM;
	206	goto out;
	207	}
	208	}
	209	skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
6b7326c8	210	ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
1da177e4 LT	211	if (unlikely(sg != &esp->sgbuf[0]))
1da177e4 LT	212	kfree(sg);
6b7326c8 HX	213	if (unlikely(ret))
6b7326c8 HX	214	goto out;
1da177e4 LT	215
	216	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
	217	BUG();
	218
	219	padlen = nexthdr[0];
	220	if (padlen+2 >= elen) {
64ce2073	221	LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
1da177e4 LT	222	ret = -EINVAL;
	223	goto out;
	224	}
1ab1457c	225	/* ... check padding bits here. Silly. :-) */
1da177e4 LT	226
1da177e4 LT	227	pskb_trim(skb, skb->len - alen - padlen - 2);
1da177e4 LT	228	ret = nexthdr[1];
	229	}
	230
31a4ab93 HX	231	skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
31a4ab93 HX	232
1da177e4	233	out:
1da177e4 LT	234	return ret;
	235	}
	236
	237	static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
	238	{
	239	struct esp_data *esp = x->data;
6b7326c8	240	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
1da177e4	241
7e49e6de	242	if (x->props.mode == XFRM_MODE_TUNNEL) {
a02a6422	243	mtu = ALIGN(mtu + 2, blksize);
1da177e4 LT	244	} else {
1da177e4 LT	245	/* The worst case. */
d4875b04 HX	246	u32 padsize = ((blksize - 1) & 7) + 1;
d4875b04 HX	247	mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
1da177e4 LT	248	}
1da177e4 LT	249	if (esp->conf.padlen)
a02a6422	250	mtu = ALIGN(mtu, esp->conf.padlen);
1da177e4	251
73d4f84f	252	return mtu + x->props.header_len + esp->auth.icv_trunc_len;
1da177e4 LT	253	}
	254
	255	static void esp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
1ab1457c	256	int type, int code, int offset, __be32 info)
1da177e4 LT	257	{
	258	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	259	struct ipv6_esp_hdr esph = (struct ipv6_esp_hdr)(skb->data+offset);
	260	struct xfrm_state *x;
	261
1ab1457c	262	if (type != ICMPV6_DEST_UNREACH &&
1da177e4 LT	263	type != ICMPV6_PKT_TOOBIG)
	264	return;
	265
	266	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
	267	if (!x)
	268	return;
1ab1457c	269	printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
1da177e4 LT	270	ntohl(esph->spi), NIP6(iph->daddr));
	271	xfrm_state_put(x);
	272	}
	273
	274	static void esp6_destroy(struct xfrm_state *x)
	275	{
	276	struct esp_data *esp = x->data;
	277
	278	if (!esp)
	279	return;
	280
6b7326c8	281	crypto_free_blkcipher(esp->conf.tfm);
573dbd95 JJ	282	esp->conf.tfm = NULL;
	283	kfree(esp->conf.ivec);
	284	esp->conf.ivec = NULL;
07d4ee58	285	crypto_free_hash(esp->auth.tfm);
573dbd95 JJ	286	esp->auth.tfm = NULL;
	287	kfree(esp->auth.work_icv);
	288	esp->auth.work_icv = NULL;
1da177e4 LT	289	kfree(esp);
	290	}
	291
72cb6962	292	static int esp6_init_state(struct xfrm_state *x)
1da177e4 LT	293	{
1da177e4 LT	294	struct esp_data *esp = NULL;
6b7326c8	295	struct crypto_blkcipher *tfm;
1da177e4 LT	296
	297	/* null auth and encryption can have zero length keys */
	298	if (x->aalg) {
	299	if (x->aalg->alg_key_len > 512)
	300	goto error;
	301	}
	302	if (x->ealg == NULL)
	303	goto error;
	304
	305	if (x->encap)
	306	goto error;
	307
0c600eda	308	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
1da177e4 LT	309	if (esp == NULL)
	310	return -ENOMEM;
	311
1da177e4 LT	312	if (x->aalg) {
1da177e4 LT	313	struct xfrm_algo_desc *aalg_desc;
07d4ee58	314	struct crypto_hash *hash;
1da177e4 LT	315
	316	esp->auth.key = x->aalg->alg_key;
	317	esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
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;
	324	if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
1da177e4	325	goto error;
1ab1457c	326
1da177e4 LT	327	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1da177e4 LT	328	BUG_ON(!aalg_desc);
1ab1457c	329
1da177e4	330	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58 HX	331	crypto_hash_digestsize(hash)) {
	332	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
	333	x->aalg->alg_name,
	334	crypto_hash_digestsize(hash),
	335	aalg_desc->uinfo.auth.icv_fullbits/8);
	336	goto error;
1da177e4	337	}
1ab1457c	338
1da177e4 LT	339	esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
1da177e4 LT	340	esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
1ab1457c	341
1da177e4 LT	342	esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
	343	if (!esp->auth.work_icv)
	344	goto error;
	345	}
	346	esp->conf.key = x->ealg->alg_key;
	347	esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
6b7326c8 HX	348	tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
6b7326c8 HX	349	if (IS_ERR(tfm))
1da177e4	350	goto error;
6b7326c8 HX	351	esp->conf.tfm = tfm;
6b7326c8 HX	352	esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
1da177e4 LT	353	esp->conf.padlen = 0;
	354	if (esp->conf.ivlen) {
	355	esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
	356	if (unlikely(esp->conf.ivec == NULL))
	357	goto error;
e4bec827	358	esp->conf.ivinitted = 0;
1da177e4	359	}
6b7326c8	360	if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
1da177e4 LT	361	goto error;
1da177e4 LT	362	x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
7e49e6de	363	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	364	x->props.header_len += sizeof(struct ipv6hdr);
	365	x->data = esp;
	366	return 0;
	367
	368	error:
	369	x->data = esp;
	370	esp6_destroy(x);
	371	x->data = NULL;
	372	return -EINVAL;
	373	}
	374
	375	static struct xfrm_type esp6_type =
	376	{
	377	.description = "ESP6",
	378	.owner = THIS_MODULE,
	379	.proto = IPPROTO_ESP,
	380	.init_state = esp6_init_state,
	381	.destructor = esp6_destroy,
	382	.get_max_size = esp6_get_max_size,
	383	.input = esp6_input,
aee5adb4 MN	384	.output = esp6_output,
aee5adb4 MN	385	.hdr_offset = xfrm6_find_1stfragopt,
1da177e4 LT	386	};
	387
	388	static struct inet6_protocol esp6_protocol = {
	389	.handler = xfrm6_rcv,
	390	.err_handler = esp6_err,
	391	.flags = INET6_PROTO_NOPOLICY,
	392	};
	393
	394	static int __init esp6_init(void)
	395	{
	396	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
	397	printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
	398	return -EAGAIN;
	399	}
	400	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
	401	printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
	402	xfrm_unregister_type(&esp6_type, AF_INET6);
	403	return -EAGAIN;
	404	}
	405
	406	return 0;
	407	}
	408
	409	static void __exit esp6_fini(void)
	410	{
	411	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
	412	printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
	413	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
	414	printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
	415	}
	416
	417	module_init(esp6_init);
	418	module_exit(esp6_fini);
	419
	420	MODULE_LICENSE("GPL");