[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;
	int hdr_len;
	struct ipv6hdr *top_iph;
	struct ipv6_esp_hdr *esph;
	struct crypto_blkcipher *tfm;
	struct blkcipher_desc desc;
	struct esp_data *esp;
	struct sk_buff *trailer;
	int blksize;
	int clen;
	int alen;
	int nfrags;

	esp = x->data;
	hdr_len = skb->h.raw - skb->data +
		  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->nh.raw;
	*skb->nh.raw = IPPROTO_ESP;

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

	if (esp->conf.ivlen)
		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 = skb->nh.ipv6h;

	/* 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, __u32 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;
		get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
	}
	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
};

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	/*
	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 <[email protected]>
	23	*
	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;
	45	int hdr_len;
	46	struct ipv6hdr *top_iph;
	47	struct ipv6_esp_hdr *esph;
6b7326c8 HX	48	struct crypto_blkcipher *tfm;
6b7326c8 HX	49	struct blkcipher_desc desc;
1da177e4 LT	50	struct esp_data *esp;
	51	struct sk_buff *trailer;
	52	int blksize;
	53	int clen;
	54	int alen;
	55	int nfrags;
	56
	57	esp = x->data;
	58	hdr_len = skb->h.raw - skb->data +
	59	sizeof(*esph) + esp->conf.ivlen;
	60
	61	/* Strip IP+ESP header. */
	62	__skb_pull(skb, hdr_len);
	63
	64	/* Now skb is pure payload to encrypt */
	65	err = -ENOMEM;
	66
	67	/* Round to block size */
	68	clen = skb->len;
	69
	70	alen = esp->auth.icv_trunc_len;
	71	tfm = esp->conf.tfm;
6b7326c8 HX	72	desc.tfm = tfm;
	73	desc.flags = 0;
	74	blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
a02a6422	75	clen = ALIGN(clen + 2, blksize);
1da177e4	76	if (esp->conf.padlen)
a02a6422	77	clen = ALIGN(clen, esp->conf.padlen);
1da177e4 LT	78
	79	if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
	80	goto error;
	81	}
	82
	83	/* Fill padding... */
	84	do {
	85	int i;
	86	for (i=0; i<clen-skb->len - 2; i++)
	87	(u8)(trailer->tail + i) = i+1;
	88	} while (0);
	89	(u8)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
	90	pskb_put(skb, trailer, clen - skb->len);
	91
	92	top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
	93	esph = (struct ipv6_esp_hdr *)skb->h.raw;
	94	top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
	95	(u8)(trailer->tail - 1) = *skb->nh.raw;
	96	*skb->nh.raw = IPPROTO_ESP;
	97
	98	esph->spi = x->id.spi;
	99	esph->seq_no = htonl(++x->replay.oseq);
9500e8a8	100	xfrm_aevent_doreplay(x);
1da177e4 LT	101
1da177e4 LT	102	if (esp->conf.ivlen)
6b7326c8	103	crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
1da177e4 LT	104
	105	do {
	106	struct scatterlist *sg = &esp->sgbuf[0];
	107
	108	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	109	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	110	if (!sg)
	111	goto error;
	112	}
	113	skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
6b7326c8	114	err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
1da177e4 LT	115	if (unlikely(sg != &esp->sgbuf[0]))
	116	kfree(sg);
	117	} while (0);
	118
6b7326c8 HX	119	if (unlikely(err))
	120	goto error;
	121
1da177e4	122	if (esp->conf.ivlen) {
6b7326c8 HX	123	memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
6b7326c8 HX	124	crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
1da177e4 LT	125	}
	126
	127	if (esp->auth.icv_full_len) {
07d4ee58 HX	128	err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
	129	sizeof(*esph) + esp->conf.ivlen + clen);
	130	memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
1da177e4 LT	131	}
1da177e4 LT	132
1da177e4 LT	133	error:
	134	return err;
	135	}
	136
e695633e	137	static int esp6_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	138	{
	139	struct ipv6hdr *iph;
	140	struct ipv6_esp_hdr *esph;
	141	struct esp_data *esp = x->data;
6b7326c8 HX	142	struct crypto_blkcipher *tfm = esp->conf.tfm;
6b7326c8 HX	143	struct blkcipher_desc desc = { .tfm = tfm };
1da177e4	144	struct sk_buff *trailer;
6b7326c8	145	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
1da177e4 LT	146	int alen = esp->auth.icv_trunc_len;
	147	int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
	148
	149	int hdr_len = skb->h.raw - skb->nh.raw;
	150	int nfrags;
1da177e4 LT	151	int ret = 0;
	152
	153	if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
	154	ret = -EINVAL;
31a4ab93	155	goto out;
1da177e4 LT	156	}
	157
	158	if (elen <= 0 \|\| (elen & (blksize-1))) {
	159	ret = -EINVAL;
31a4ab93	160	goto out;
1da177e4	161	}
1da177e4 LT	162
	163	/* If integrity check is required, do this. */
	164	if (esp->auth.icv_full_len) {
07d4ee58	165	u8 sum[alen];
1da177e4	166
07d4ee58 HX	167	ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
	168	if (ret)
	169	goto out;
1da177e4	170
07d4ee58	171	if (skb_copy_bits(skb, skb->len - alen, sum, alen))
1da177e4 LT	172	BUG();
1da177e4 LT	173
07d4ee58	174	if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
1da177e4 LT	175	x->stats.integrity_failed++;
	176	ret = -EINVAL;
	177	goto out;
	178	}
	179	}
	180
	181	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
	182	ret = -EINVAL;
	183	goto out;
	184	}
	185
	186	skb->ip_summed = CHECKSUM_NONE;
	187
	188	esph = (struct ipv6_esp_hdr*)skb->data;
	189	iph = skb->nh.ipv6h;
	190
	191	/* Get ivec. This can be wrong, check against another impls. */
	192	if (esp->conf.ivlen)
6b7326c8	193	crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
1da177e4 LT	194
	195	{
	196	u8 nexthdr[2];
	197	struct scatterlist *sg = &esp->sgbuf[0];
	198	u8 padlen;
	199
	200	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	201	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	202	if (!sg) {
	203	ret = -ENOMEM;
	204	goto out;
	205	}
	206	}
	207	skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
6b7326c8	208	ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
1da177e4 LT	209	if (unlikely(sg != &esp->sgbuf[0]))
1da177e4 LT	210	kfree(sg);
6b7326c8 HX	211	if (unlikely(ret))
6b7326c8 HX	212	goto out;
1da177e4 LT	213
	214	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
	215	BUG();
	216
	217	padlen = nexthdr[0];
	218	if (padlen+2 >= elen) {
64ce2073	219	LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
1da177e4 LT	220	ret = -EINVAL;
	221	goto out;
	222	}
	223	/* ... check padding bits here. Silly. :-) */
	224
	225	pskb_trim(skb, skb->len - alen - padlen - 2);
1da177e4 LT	226	ret = nexthdr[1];
	227	}
	228
31a4ab93 HX	229	skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
31a4ab93 HX	230
1da177e4	231	out:
1da177e4 LT	232	return ret;
	233	}
	234
	235	static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
	236	{
	237	struct esp_data *esp = x->data;
6b7326c8	238	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
1da177e4	239
7e49e6de	240	if (x->props.mode == XFRM_MODE_TUNNEL) {
a02a6422	241	mtu = ALIGN(mtu + 2, blksize);
1da177e4 LT	242	} else {
1da177e4 LT	243	/* The worst case. */
d4875b04 HX	244	u32 padsize = ((blksize - 1) & 7) + 1;
d4875b04 HX	245	mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
1da177e4 LT	246	}
1da177e4 LT	247	if (esp->conf.padlen)
a02a6422	248	mtu = ALIGN(mtu, esp->conf.padlen);
1da177e4	249
73d4f84f	250	return mtu + x->props.header_len + esp->auth.icv_trunc_len;
1da177e4 LT	251	}
	252
	253	static void esp6_err(struct sk_buff skb, struct inet6_skb_parm opt,
	254	int type, int code, int offset, __u32 info)
	255	{
	256	struct ipv6hdr iph = (struct ipv6hdr)skb->data;
	257	struct ipv6_esp_hdr esph = (struct ipv6_esp_hdr)(skb->data+offset);
	258	struct xfrm_state *x;
	259
	260	if (type != ICMPV6_DEST_UNREACH &&
	261	type != ICMPV6_PKT_TOOBIG)
	262	return;
	263
	264	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
	265	if (!x)
	266	return;
46b86a2d	267	printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
1da177e4 LT	268	ntohl(esph->spi), NIP6(iph->daddr));
	269	xfrm_state_put(x);
	270	}
	271
	272	static void esp6_destroy(struct xfrm_state *x)
	273	{
	274	struct esp_data *esp = x->data;
	275
	276	if (!esp)
	277	return;
	278
6b7326c8	279	crypto_free_blkcipher(esp->conf.tfm);
573dbd95 JJ	280	esp->conf.tfm = NULL;
	281	kfree(esp->conf.ivec);
	282	esp->conf.ivec = NULL;
07d4ee58	283	crypto_free_hash(esp->auth.tfm);
573dbd95 JJ	284	esp->auth.tfm = NULL;
	285	kfree(esp->auth.work_icv);
	286	esp->auth.work_icv = NULL;
1da177e4 LT	287	kfree(esp);
	288	}
	289
72cb6962	290	static int esp6_init_state(struct xfrm_state *x)
1da177e4 LT	291	{
1da177e4 LT	292	struct esp_data *esp = NULL;
6b7326c8	293	struct crypto_blkcipher *tfm;
1da177e4 LT	294
	295	/* null auth and encryption can have zero length keys */
	296	if (x->aalg) {
	297	if (x->aalg->alg_key_len > 512)
	298	goto error;
	299	}
	300	if (x->ealg == NULL)
	301	goto error;
	302
	303	if (x->encap)
	304	goto error;
	305
0c600eda	306	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
1da177e4 LT	307	if (esp == NULL)
	308	return -ENOMEM;
	309
1da177e4 LT	310	if (x->aalg) {
1da177e4 LT	311	struct xfrm_algo_desc *aalg_desc;
07d4ee58	312	struct crypto_hash *hash;
1da177e4 LT	313
	314	esp->auth.key = x->aalg->alg_key;
	315	esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
07d4ee58 HX	316	hash = crypto_alloc_hash(x->aalg->alg_name, 0,
	317	CRYPTO_ALG_ASYNC);
	318	if (IS_ERR(hash))
	319	goto error;
	320
	321	esp->auth.tfm = hash;
	322	if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
1da177e4	323	goto error;
1da177e4 LT	324
	325	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	326	BUG_ON(!aalg_desc);
	327
	328	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58 HX	329	crypto_hash_digestsize(hash)) {
	330	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
	331	x->aalg->alg_name,
	332	crypto_hash_digestsize(hash),
	333	aalg_desc->uinfo.auth.icv_fullbits/8);
	334	goto error;
1da177e4 LT	335	}
	336
	337	esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	338	esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
	339
	340	esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
	341	if (!esp->auth.work_icv)
	342	goto error;
	343	}
	344	esp->conf.key = x->ealg->alg_key;
	345	esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
6b7326c8 HX	346	tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
6b7326c8 HX	347	if (IS_ERR(tfm))
1da177e4	348	goto error;
6b7326c8 HX	349	esp->conf.tfm = tfm;
6b7326c8 HX	350	esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
1da177e4 LT	351	esp->conf.padlen = 0;
	352	if (esp->conf.ivlen) {
	353	esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
	354	if (unlikely(esp->conf.ivec == NULL))
	355	goto error;
	356	get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
	357	}
6b7326c8	358	if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
1da177e4 LT	359	goto error;
1da177e4 LT	360	x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
7e49e6de	361	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	362	x->props.header_len += sizeof(struct ipv6hdr);
	363	x->data = esp;
	364	return 0;
	365
	366	error:
	367	x->data = esp;
	368	esp6_destroy(x);
	369	x->data = NULL;
	370	return -EINVAL;
	371	}
	372
	373	static struct xfrm_type esp6_type =
	374	{
	375	.description = "ESP6",
	376	.owner = THIS_MODULE,
	377	.proto = IPPROTO_ESP,
	378	.init_state = esp6_init_state,
	379	.destructor = esp6_destroy,
	380	.get_max_size = esp6_get_max_size,
	381	.input = esp6_input,
	382	.output = esp6_output
	383	};
	384
	385	static struct inet6_protocol esp6_protocol = {
	386	.handler = xfrm6_rcv,
	387	.err_handler = esp6_err,
	388	.flags = INET6_PROTO_NOPOLICY,
	389	};
	390
	391	static int __init esp6_init(void)
	392	{
	393	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
	394	printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
	395	return -EAGAIN;
	396	}
	397	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
	398	printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
	399	xfrm_unregister_type(&esp6_type, AF_INET6);
	400	return -EAGAIN;
	401	}
	402
	403	return 0;
	404	}
	405
	406	static void __exit esp6_fini(void)
	407	{
	408	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
	409	printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
	410	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
	411	printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
	412	}
	413
	414	module_init(esp6_init);
	415	module_exit(esp6_fini);
	416
	417	MODULE_LICENSE("GPL");