[mirror_ubuntu-zesty-kernel.git] / net / ipv4 / esp4.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/protocol.h>
#include <net/udp.h>

static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct iphdr *top_iph;
	struct ip_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;

	/* Strip IP+ESP header. */
	__skb_pull(skb, skb->h.raw - skb->data);
	/* Now skb is pure payload to encrypt */

	err = -ENOMEM;

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

	esp = x->data;
	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);

	__skb_push(skb, skb->data - skb_network_header(skb));
	top_iph = skb->nh.iph;
	esph = (struct ip_esp_hdr *)(skb_network_header(skb) +
				     top_iph->ihl * 4);
	top_iph->tot_len = htons(skb->len + alen);
	*(u8*)(trailer->tail - 1) = top_iph->protocol;

	/* this is non-NULL only with UDP Encapsulation */
	if (x->encap) {
		struct xfrm_encap_tmpl *encap = x->encap;
		struct udphdr *uh;
		__be32 *udpdata32;

		uh = (struct udphdr *)esph;
		uh->source = encap->encap_sport;
		uh->dest = encap->encap_dport;
		uh->len = htons(skb->len + alen - top_iph->ihl*4);
		uh->check = 0;

		switch (encap->encap_type) {
		default:
		case UDP_ENCAP_ESPINUDP:
			esph = (struct ip_esp_hdr *)(uh + 1);
			break;
		case UDP_ENCAP_ESPINUDP_NON_IKE:
			udpdata32 = (__be32 *)(uh + 1);
			udpdata32[0] = udpdata32[1] = 0;
			esph = (struct ip_esp_hdr *)(udpdata32 + 2);
			break;
		}

		top_iph->protocol = IPPROTO_UDP;
	} else
		top_iph->protocol = 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);
	}

	ip_send_check(top_iph);

error:
	return err;
}

/*
 * Note: detecting truncated vs. non-truncated authentication data is very
 * expensive, so we only support truncated data, which is the recommended
 * and common case.
 */
static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
{
	struct iphdr *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(struct ip_esp_hdr) - esp->conf.ivlen - alen;
	int nfrags;
	int ihl;
	u8 nexthdr[2];
	struct scatterlist *sg;
	int padlen;
	int err;

	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
		goto out;

	if (elen <= 0 || (elen & (blksize-1)))
		goto out;

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

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

	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
		goto out;

	skb->ip_summed = CHECKSUM_NONE;

	esph = (struct ip_esp_hdr*)skb->data;

	/* 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);

	sg = &esp->sgbuf[0];

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

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

	padlen = nexthdr[0];
	if (padlen+2 >= elen)
		goto out;

	/* ... check padding bits here. Silly. :-) */

	iph = skb->nh.iph;
	ihl = iph->ihl * 4;

	if (x->encap) {
		struct xfrm_encap_tmpl *encap = x->encap;
		struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);

		/*
		 * 1) if the NAT-T peer's IP or port changed then
		 *    advertize the change to the keying daemon.
		 *    This is an inbound SA, so just compare
		 *    SRC ports.
		 */
		if (iph->saddr != x->props.saddr.a4 ||
		    uh->source != encap->encap_sport) {
			xfrm_address_t ipaddr;

			ipaddr.a4 = iph->saddr;
			km_new_mapping(x, &ipaddr, uh->source);

			/* XXX: perhaps add an extra
			 * policy check here, to see
			 * if we should allow or
			 * reject a packet from a
			 * different source
			 * address/port.
			 */
		}

		/*
		 * 2) ignore UDP/TCP checksums in case
		 *    of NAT-T in Transport Mode, or
		 *    perform other post-processing fixes
		 *    as per draft-ietf-ipsec-udp-encaps-06,
		 *    section 3.1.2
		 */
		if (x->props.mode == XFRM_MODE_TRANSPORT ||
		    x->props.mode == XFRM_MODE_BEET)
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	iph->protocol = nexthdr[1];
	pskb_trim(skb, skb->len - alen - padlen - 2);
	skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - ihl;

	return 0;

out:
	return -EINVAL;
}

static u32 esp4_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);
	int enclen = 0;

	switch (x->props.mode) {
	case XFRM_MODE_TUNNEL:
		mtu = ALIGN(mtu +2, blksize);
		break;
	default:
	case XFRM_MODE_TRANSPORT:
		/* The worst case */
		mtu = ALIGN(mtu + 2, 4) + blksize - 4;
		break;
	case XFRM_MODE_BEET:
		/* The worst case. */
		enclen = IPV4_BEET_PHMAXLEN;
		mtu = ALIGN(mtu + enclen + 2, blksize);
		break;
	}

	if (esp->conf.padlen)
		mtu = ALIGN(mtu, esp->conf.padlen);

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

static void esp4_err(struct sk_buff *skb, u32 info)
{
	struct iphdr *iph = (struct iphdr*)skb->data;
	struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
	    skb->h.icmph->code != ICMP_FRAG_NEEDED)
		return;

	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
	if (!x)
		return;
	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
		 ntohl(esph->spi), ntohl(iph->daddr));
	xfrm_state_put(x);
}

static void esp_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 esp_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;

	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 ip_esp_hdr) + esp->conf.ivlen;
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct iphdr);
	if (x->encap) {
		struct xfrm_encap_tmpl *encap = x->encap;

		switch (encap->encap_type) {
		default:
			goto error;
		case UDP_ENCAP_ESPINUDP:
			x->props.header_len += sizeof(struct udphdr);
			break;
		case UDP_ENCAP_ESPINUDP_NON_IKE:
			x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
			break;
		}
	}
	x->data = esp;
	x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
	return 0;

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

static struct xfrm_type esp_type =
{
	.description	= "ESP4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_ESP,
	.init_state	= esp_init_state,
	.destructor	= esp_destroy,
	.get_max_size	= esp4_get_max_size,
	.input		= esp_input,
	.output		= esp_output
};

static struct net_protocol esp4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	esp4_err,
	.no_policy	=	1,
};

static int __init esp4_init(void)
{
	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
		printk(KERN_INFO "ip esp init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
		printk(KERN_INFO "ip esp init: can't add protocol\n");
		xfrm_unregister_type(&esp_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit esp4_fini(void)
{
	if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
		printk(KERN_INFO "ip esp close: can't remove protocol\n");
	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
		printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
}

module_init(esp4_init);
module_exit(esp4_fini);
MODULE_LICENSE("GPL");
Commit	Line	Data
6b7326c8	1	#include <linux/err.h>
1da177e4 LT	2	#include <linux/module.h>
	3	#include <net/ip.h>
	4	#include <net/xfrm.h>
	5	#include <net/esp.h>
	6	#include <asm/scatterlist.h>
	7	#include <linux/crypto.h>
a02a6422	8	#include <linux/kernel.h>
1da177e4 LT	9	#include <linux/pfkeyv2.h>
	10	#include <linux/random.h>
	11	#include <net/icmp.h>
14c85021	12	#include <net/protocol.h>
1da177e4 LT	13	#include <net/udp.h>
1da177e4 LT	14
1da177e4 LT	15	static int esp_output(struct xfrm_state x, struct sk_buff skb)
	16	{
	17	int err;
	18	struct iphdr *top_iph;
	19	struct ip_esp_hdr *esph;
6b7326c8 HX	20	struct crypto_blkcipher *tfm;
6b7326c8 HX	21	struct blkcipher_desc desc;
1da177e4 LT	22	struct esp_data *esp;
	23	struct sk_buff *trailer;
	24	int blksize;
	25	int clen;
	26	int alen;
	27	int nfrags;
	28
	29	/* Strip IP+ESP header. */
	30	__skb_pull(skb, skb->h.raw - skb->data);
	31	/* Now skb is pure payload to encrypt */
	32
	33	err = -ENOMEM;
	34
	35	/* Round to block size */
	36	clen = skb->len;
	37
	38	esp = x->data;
	39	alen = esp->auth.icv_trunc_len;
	40	tfm = esp->conf.tfm;
6b7326c8 HX	41	desc.tfm = tfm;
	42	desc.flags = 0;
	43	blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
a02a6422	44	clen = ALIGN(clen + 2, blksize);
1da177e4	45	if (esp->conf.padlen)
a02a6422	46	clen = ALIGN(clen, esp->conf.padlen);
1da177e4 LT	47
	48	if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0)
	49	goto error;
	50
	51	/* Fill padding... */
	52	do {
	53	int i;
	54	for (i=0; i<clen-skb->len - 2; i++)
	55	(u8)(trailer->tail + i) = i+1;
	56	} while (0);
	57	(u8)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
	58	pskb_put(skb, trailer, clen - skb->len);
	59
d56f90a7	60	__skb_push(skb, skb->data - skb_network_header(skb));
1da177e4	61	top_iph = skb->nh.iph;
d56f90a7 ACM	62	esph = (struct ip_esp_hdr *)(skb_network_header(skb) +
d56f90a7 ACM	63	top_iph->ihl * 4);
1da177e4 LT	64	top_iph->tot_len = htons(skb->len + alen);
	65	(u8)(trailer->tail - 1) = top_iph->protocol;
	66
	67	/* this is non-NULL only with UDP Encapsulation */
	68	if (x->encap) {
	69	struct xfrm_encap_tmpl *encap = x->encap;
	70	struct udphdr *uh;
d5a0a1e3	71	__be32 *udpdata32;
1da177e4 LT	72
	73	uh = (struct udphdr *)esph;
	74	uh->source = encap->encap_sport;
	75	uh->dest = encap->encap_dport;
	76	uh->len = htons(skb->len + alen - top_iph->ihl*4);
	77	uh->check = 0;
	78
	79	switch (encap->encap_type) {
	80	default:
	81	case UDP_ENCAP_ESPINUDP:
	82	esph = (struct ip_esp_hdr *)(uh + 1);
	83	break;
	84	case UDP_ENCAP_ESPINUDP_NON_IKE:
d5a0a1e3	85	udpdata32 = (__be32 *)(uh + 1);
1da177e4 LT	86	udpdata32[0] = udpdata32[1] = 0;
	87	esph = (struct ip_esp_hdr *)(udpdata32 + 2);
	88	break;
	89	}
	90
	91	top_iph->protocol = IPPROTO_UDP;
	92	} else
	93	top_iph->protocol = IPPROTO_ESP;
	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	}
	134
	135	ip_send_check(top_iph);
	136
1da177e4 LT	137	error:
	138	return err;
	139	}
	140
	141	/*
	142	* Note: detecting truncated vs. non-truncated authentication data is very
	143	* expensive, so we only support truncated data, which is the recommended
	144	* and common case.
	145	*/
e695633e	146	static int esp_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	147	{
	148	struct iphdr *iph;
	149	struct ip_esp_hdr *esph;
	150	struct esp_data *esp = x->data;
6b7326c8 HX	151	struct crypto_blkcipher *tfm = esp->conf.tfm;
6b7326c8 HX	152	struct blkcipher_desc desc = { .tfm = tfm };
1da177e4	153	struct sk_buff *trailer;
6b7326c8	154	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
1da177e4 LT	155	int alen = esp->auth.icv_trunc_len;
	156	int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
	157	int nfrags;
31a4ab93	158	int ihl;
4bf05ece HX	159	u8 nexthdr[2];
4bf05ece HX	160	struct scatterlist *sg;
4bf05ece	161	int padlen;
6b7326c8	162	int err;
1da177e4 LT	163
	164	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
	165	goto out;
	166
	167	if (elen <= 0 \|\| (elen & (blksize-1)))
	168	goto out;
	169
	170	/* If integrity check is required, do this. */
	171	if (esp->auth.icv_full_len) {
07d4ee58	172	u8 sum[alen];
1da177e4	173
07d4ee58 HX	174	err = esp_mac_digest(esp, skb, 0, skb->len - alen);
	175	if (err)
	176	goto out;
	177
	178	if (skb_copy_bits(skb, skb->len - alen, sum, alen))
1da177e4 LT	179	BUG();
1da177e4 LT	180
07d4ee58	181	if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
1da177e4 LT	182	x->stats.integrity_failed++;
	183	goto out;
	184	}
	185	}
	186
	187	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
	188	goto out;
	189
	190	skb->ip_summed = CHECKSUM_NONE;
	191
	192	esph = (struct ip_esp_hdr*)skb->data;
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
4bf05ece	198	sg = &esp->sgbuf[0];
1da177e4	199
4bf05ece HX	200	if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
	201	sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
	202	if (!sg)
	203	goto out;
	204	}
	205	skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
6b7326c8	206	err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
4bf05ece HX	207	if (unlikely(sg != &esp->sgbuf[0]))
4bf05ece HX	208	kfree(sg);
6b7326c8 HX	209	if (unlikely(err))
6b7326c8 HX	210	return err;
1da177e4	211
4bf05ece HX	212	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
4bf05ece HX	213	BUG();
1da177e4	214
4bf05ece HX	215	padlen = nexthdr[0];
	216	if (padlen+2 >= elen)
	217	goto out;
1da177e4	218
e905a9ed	219	/* ... check padding bits here. Silly. :-) */
1da177e4	220
31a4ab93 HX	221	iph = skb->nh.iph;
	222	ihl = iph->ihl * 4;
	223
752c1f4c HX	224	if (x->encap) {
752c1f4c HX	225	struct xfrm_encap_tmpl *encap = x->encap;
d56f90a7	226	struct udphdr uh = (void )(skb_network_header(skb) + ihl);
752c1f4c HX	227
	228	/*
	229	* 1) if the NAT-T peer's IP or port changed then
	230	* advertize the change to the keying daemon.
	231	* This is an inbound SA, so just compare
	232	* SRC ports.
	233	*/
	234	if (iph->saddr != x->props.saddr.a4 \|\|
	235	uh->source != encap->encap_sport) {
	236	xfrm_address_t ipaddr;
	237
	238	ipaddr.a4 = iph->saddr;
	239	km_new_mapping(x, &ipaddr, uh->source);
e905a9ed	240
752c1f4c HX	241	/* XXX: perhaps add an extra
	242	* policy check here, to see
	243	* if we should allow or
	244	* reject a packet from a
	245	* different source
	246	* address/port.
	247	*/
1da177e4	248	}
e905a9ed	249
752c1f4c HX	250	/*
	251	* 2) ignore UDP/TCP checksums in case
	252	* of NAT-T in Transport Mode, or
	253	* perform other post-processing fixes
	254	* as per draft-ietf-ipsec-udp-encaps-06,
	255	* section 3.1.2
	256	*/
0a69452c DB	257	if (x->props.mode == XFRM_MODE_TRANSPORT \|\|
0a69452c DB	258	x->props.mode == XFRM_MODE_BEET)
752c1f4c	259	skb->ip_summed = CHECKSUM_UNNECESSARY;
1da177e4 LT	260	}
1da177e4 LT	261
4bf05ece HX	262	iph->protocol = nexthdr[1];
4bf05ece HX	263	pskb_trim(skb, skb->len - alen - padlen - 2);
31a4ab93	264	skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - ihl;
4bf05ece	265
1da177e4 LT	266	return 0;
	267
	268	out:
	269	return -EINVAL;
	270	}
	271
1da177e4 LT	272	static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
	273	{
	274	struct esp_data *esp = x->data;
6b7326c8	275	u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
0a69452c DB	276	int enclen = 0;
	277
	278	switch (x->props.mode) {
	279	case XFRM_MODE_TUNNEL:
	280	mtu = ALIGN(mtu +2, blksize);
	281	break;
	282	default:
	283	case XFRM_MODE_TRANSPORT:
	284	/* The worst case */
d4875b04	285	mtu = ALIGN(mtu + 2, 4) + blksize - 4;
0a69452c DB	286	break;
0a69452c DB	287	case XFRM_MODE_BEET:
e905a9ed	288	/* The worst case. */
0a69452c DB	289	enclen = IPV4_BEET_PHMAXLEN;
	290	mtu = ALIGN(mtu + enclen + 2, blksize);
	291	break;
1da177e4	292	}
0a69452c	293
1da177e4	294	if (esp->conf.padlen)
a02a6422	295	mtu = ALIGN(mtu, esp->conf.padlen);
1da177e4	296
0a69452c	297	return mtu + x->props.header_len + esp->auth.icv_trunc_len - enclen;
1da177e4 LT	298	}
	299
	300	static void esp4_err(struct sk_buff *skb, u32 info)
	301	{
	302	struct iphdr iph = (struct iphdr)skb->data;
	303	struct ip_esp_hdr esph = (struct ip_esp_hdr)(skb->data+(iph->ihl<<2));
	304	struct xfrm_state *x;
	305
	306	if (skb->h.icmph->type != ICMP_DEST_UNREACH \|\|
	307	skb->h.icmph->code != ICMP_FRAG_NEEDED)
	308	return;
	309
	310	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
	311	if (!x)
	312	return;
64ce2073 PM	313	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
64ce2073 PM	314	ntohl(esph->spi), ntohl(iph->daddr));
1da177e4 LT	315	xfrm_state_put(x);
	316	}
	317
	318	static void esp_destroy(struct xfrm_state *x)
	319	{
	320	struct esp_data *esp = x->data;
	321
	322	if (!esp)
	323	return;
	324
6b7326c8	325	crypto_free_blkcipher(esp->conf.tfm);
573dbd95 JJ	326	esp->conf.tfm = NULL;
	327	kfree(esp->conf.ivec);
	328	esp->conf.ivec = NULL;
07d4ee58	329	crypto_free_hash(esp->auth.tfm);
573dbd95 JJ	330	esp->auth.tfm = NULL;
	331	kfree(esp->auth.work_icv);
	332	esp->auth.work_icv = NULL;
1da177e4 LT	333	kfree(esp);
	334	}
	335
72cb6962	336	static int esp_init_state(struct xfrm_state *x)
1da177e4 LT	337	{
1da177e4 LT	338	struct esp_data *esp = NULL;
6b7326c8	339	struct crypto_blkcipher *tfm;
1da177e4 LT	340
	341	/* null auth and encryption can have zero length keys */
	342	if (x->aalg) {
	343	if (x->aalg->alg_key_len > 512)
	344	goto error;
	345	}
	346	if (x->ealg == NULL)
	347	goto error;
	348
0da974f4	349	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
1da177e4 LT	350	if (esp == NULL)
	351	return -ENOMEM;
	352
1da177e4 LT	353	if (x->aalg) {
1da177e4 LT	354	struct xfrm_algo_desc *aalg_desc;
07d4ee58	355	struct crypto_hash *hash;
1da177e4 LT	356
	357	esp->auth.key = x->aalg->alg_key;
	358	esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
07d4ee58 HX	359	hash = crypto_alloc_hash(x->aalg->alg_name, 0,
	360	CRYPTO_ALG_ASYNC);
	361	if (IS_ERR(hash))
	362	goto error;
	363
	364	esp->auth.tfm = hash;
	365	if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
1da177e4	366	goto error;
1da177e4 LT	367
	368	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	369	BUG_ON(!aalg_desc);
	370
	371	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
07d4ee58	372	crypto_hash_digestsize(hash)) {
64ce2073 PM	373	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
64ce2073 PM	374	x->aalg->alg_name,
07d4ee58	375	crypto_hash_digestsize(hash),
64ce2073	376	aalg_desc->uinfo.auth.icv_fullbits/8);
1da177e4 LT	377	goto error;
	378	}
	379
	380	esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	381	esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
	382
	383	esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
	384	if (!esp->auth.work_icv)
	385	goto error;
	386	}
	387	esp->conf.key = x->ealg->alg_key;
	388	esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
6b7326c8 HX	389	tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
6b7326c8 HX	390	if (IS_ERR(tfm))
1da177e4	391	goto error;
6b7326c8 HX	392	esp->conf.tfm = tfm;
6b7326c8 HX	393	esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
1da177e4 LT	394	esp->conf.padlen = 0;
	395	if (esp->conf.ivlen) {
	396	esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
	397	if (unlikely(esp->conf.ivec == NULL))
	398	goto error;
e4bec827	399	esp->conf.ivinitted = 0;
1da177e4	400	}
6b7326c8	401	if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
1da177e4 LT	402	goto error;
1da177e4 LT	403	x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
7e49e6de	404	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	405	x->props.header_len += sizeof(struct iphdr);
	406	if (x->encap) {
	407	struct xfrm_encap_tmpl *encap = x->encap;
	408
	409	switch (encap->encap_type) {
	410	default:
	411	goto error;
	412	case UDP_ENCAP_ESPINUDP:
	413	x->props.header_len += sizeof(struct udphdr);
	414	break;
	415	case UDP_ENCAP_ESPINUDP_NON_IKE:
	416	x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
	417	break;
	418	}
	419	}
	420	x->data = esp;
	421	x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
	422	return 0;
	423
	424	error:
	425	x->data = esp;
	426	esp_destroy(x);
	427	x->data = NULL;
	428	return -EINVAL;
	429	}
	430
	431	static struct xfrm_type esp_type =
	432	{
	433	.description = "ESP4",
	434	.owner = THIS_MODULE,
	435	.proto = IPPROTO_ESP,
	436	.init_state = esp_init_state,
	437	.destructor = esp_destroy,
	438	.get_max_size = esp4_get_max_size,
	439	.input = esp_input,
1da177e4 LT	440	.output = esp_output
	441	};
	442
	443	static struct net_protocol esp4_protocol = {
	444	.handler = xfrm4_rcv,
	445	.err_handler = esp4_err,
	446	.no_policy = 1,
	447	};
	448
	449	static int __init esp4_init(void)
	450	{
1da177e4 LT	451	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
	452	printk(KERN_INFO "ip esp init: can't add xfrm type\n");
	453	return -EAGAIN;
	454	}
	455	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
	456	printk(KERN_INFO "ip esp init: can't add protocol\n");
	457	xfrm_unregister_type(&esp_type, AF_INET);
	458	return -EAGAIN;
	459	}
	460	return 0;
	461	}
	462
	463	static void __exit esp4_fini(void)
	464	{
	465	if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
	466	printk(KERN_INFO "ip esp close: can't remove protocol\n");
	467	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
	468	printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
	469	}
	470
	471	module_init(esp4_init);
	472	module_exit(esp4_fini);
	473	MODULE_LICENSE("GPL");