[linux.git] / net / ipv4 / esp4.c

#include <crypto/aead.h>
#include <crypto/authenc.h>
#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/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/in6.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/udp.h>

struct esp_skb_cb {
	struct xfrm_skb_cb xfrm;
	void *tmp;
};

#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))

/*
 * Allocate an AEAD request structure with extra space for SG and IV.
 *
 * For alignment considerations the IV is placed at the front, followed
 * by the request and finally the SG list.
 *
 * TODO: Use spare space in skb for this where possible.
 */
static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags)
{
	unsigned int len;

	len = crypto_aead_ivsize(aead);
	if (len) {
		len += crypto_aead_alignmask(aead) &
		       ~(crypto_tfm_ctx_alignment() - 1);
		len = ALIGN(len, crypto_tfm_ctx_alignment());
	}

	len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
	len = ALIGN(len, __alignof__(struct scatterlist));

	len += sizeof(struct scatterlist) * nfrags;

	return kmalloc(len, GFP_ATOMIC);
}

static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp)
{
	return crypto_aead_ivsize(aead) ?
	       PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
}

static inline struct aead_givcrypt_request *esp_tmp_givreq(
	struct crypto_aead *aead, u8 *iv)
{
	struct aead_givcrypt_request *req;

	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
				crypto_tfm_ctx_alignment());
	aead_givcrypt_set_tfm(req, aead);
	return req;
}

static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
{
	struct aead_request *req;

	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
				crypto_tfm_ctx_alignment());
	aead_request_set_tfm(req, aead);
	return req;
}

static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
					     struct aead_request *req)
{
	return (void *)ALIGN((unsigned long)(req + 1) +
			     crypto_aead_reqsize(aead),
			     __alignof__(struct scatterlist));
}

static inline struct scatterlist *esp_givreq_sg(
	struct crypto_aead *aead, struct aead_givcrypt_request *req)
{
	return (void *)ALIGN((unsigned long)(req + 1) +
			     crypto_aead_reqsize(aead),
			     __alignof__(struct scatterlist));
}

static void esp_output_done(struct crypto_async_request *base, int err)
{
	struct sk_buff *skb = base->data;

	kfree(ESP_SKB_CB(skb)->tmp);
	xfrm_output_resume(skb, err);
}

static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct ip_esp_hdr *esph;
	struct crypto_aead *aead;
	struct aead_givcrypt_request *req;
	struct scatterlist *sg;
	struct scatterlist *asg;
	struct esp_data *esp;
	struct sk_buff *trailer;
	void *tmp;
	u8 *iv;
	u8 *tail;
	int blksize;
	int clen;
	int alen;
	int nfrags;

	/* skb is pure payload to encrypt */

	err = -ENOMEM;

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

	esp = x->data;
	aead = esp->aead;
	alen = crypto_aead_authsize(aead);

	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
	clen = ALIGN(clen + 2, blksize);
	if (esp->padlen)
		clen = ALIGN(clen, esp->padlen);

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

	tmp = esp_alloc_tmp(aead, nfrags + 1);
	if (!tmp)
		goto error;

	iv = esp_tmp_iv(aead, tmp);
	req = esp_tmp_givreq(aead, iv);
	asg = esp_givreq_sg(aead, req);
	sg = asg + 1;

	/* 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;
	tail[clen - skb->len - 1] = *skb_mac_header(skb);
	pskb_put(skb, trailer, clen - skb->len + alen);

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

	/* this is non-NULL only with UDP Encapsulation */
	if (x->encap) {
		struct xfrm_encap_tmpl *encap = x->encap;
		struct udphdr *uh;
		__be32 *udpdata32;
		__be16 sport, dport;
		int encap_type;

		spin_lock_bh(&x->lock);
		sport = encap->encap_sport;
		dport = encap->encap_dport;
		encap_type = encap->encap_type;
		spin_unlock_bh(&x->lock);

		uh = (struct udphdr *)esph;
		uh->source = sport;
		uh->dest = dport;
		uh->len = htons(skb->len - skb_transport_offset(skb));
		uh->check = 0;

		switch (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;
		}

		*skb_mac_header(skb) = IPPROTO_UDP;
	}

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

	sg_init_table(sg, nfrags);
	skb_to_sgvec(skb, sg,
		     esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
		     clen + alen);
	sg_init_one(asg, esph, sizeof(*esph));

	aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
	aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
	aead_givcrypt_set_assoc(req, asg, sizeof(*esph));
	aead_givcrypt_set_giv(req, esph->enc_data,
			      XFRM_SKB_CB(skb)->seq.output);

	ESP_SKB_CB(skb)->tmp = tmp;
	err = crypto_aead_givencrypt(req);
	if (err == -EINPROGRESS)
		goto error;

	if (err == -EBUSY)
		err = NET_XMIT_DROP;

	kfree(tmp);

error:
	return err;
}

static int esp_input_done2(struct sk_buff *skb, int err)
{
	struct iphdr *iph;
	struct xfrm_state *x = xfrm_input_state(skb);
	struct esp_data *esp = x->data;
	struct crypto_aead *aead = esp->aead;
	int alen = crypto_aead_authsize(aead);
	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
	int elen = skb->len - hlen;
	int ihl;
	u8 nexthdr[2];
	int padlen;

	kfree(ESP_SKB_CB(skb)->tmp);

	if (unlikely(err))
		goto out;

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

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

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

	iph = ip_hdr(skb);
	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)
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	pskb_trim(skb, skb->len - alen - padlen - 2);
	__skb_pull(skb, hlen);
	skb_set_transport_header(skb, -ihl);

	err = nexthdr[1];

	/* RFC4303: Drop dummy packets without any error */
	if (err == IPPROTO_NONE)
		err = -EINVAL;

out:
	return err;
}

static void esp_input_done(struct crypto_async_request *base, int err)
{
	struct sk_buff *skb = base->data;

	xfrm_input_resume(skb, esp_input_done2(skb, 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 ip_esp_hdr *esph;
	struct esp_data *esp = x->data;
	struct crypto_aead *aead = esp->aead;
	struct aead_request *req;
	struct sk_buff *trailer;
	int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
	int nfrags;
	void *tmp;
	u8 *iv;
	struct scatterlist *sg;
	struct scatterlist *asg;
	int err = -EINVAL;

	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
		goto out;

	if (elen <= 0)
		goto out;

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

	err = -ENOMEM;
	tmp = esp_alloc_tmp(aead, nfrags + 1);
	if (!tmp)
		goto out;

	ESP_SKB_CB(skb)->tmp = tmp;
	iv = esp_tmp_iv(aead, tmp);
	req = esp_tmp_req(aead, iv);
	asg = esp_req_sg(aead, req);
	sg = asg + 1;

	skb->ip_summed = CHECKSUM_NONE;

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

	/* Get ivec. This can be wrong, check against another impls. */
	iv = esph->enc_data;

	sg_init_table(sg, nfrags);
	skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
	sg_init_one(asg, esph, sizeof(*esph));

	aead_request_set_callback(req, 0, esp_input_done, skb);
	aead_request_set_crypt(req, sg, sg, elen, iv);
	aead_request_set_assoc(req, asg, sizeof(*esph));

	err = crypto_aead_decrypt(req);
	if (err == -EINPROGRESS)
		goto out;

	err = esp_input_done2(skb, err);

out:
	return err;
}

static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
{
	struct esp_data *esp = x->data;
	u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
	u32 align = max_t(u32, blksize, esp->padlen);
	u32 rem;

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

	switch (x->props.mode) {
	case XFRM_MODE_TUNNEL:
		break;
	default:
	case XFRM_MODE_TRANSPORT:
		/* The worst case */
		mtu -= blksize - 4;
		mtu += min_t(u32, blksize - 4, rem);
		break;
	case XFRM_MODE_BEET:
		/* The worst case. */
		mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
		break;
	}

	return mtu - 2;
}

static void esp4_err(struct sk_buff *skb, u32 info)
{
	struct net *net = dev_net(skb->dev);
	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 (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
	    icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
		return;

	x = xfrm_state_lookup(net, skb->mark, (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_aead(esp->aead);
	kfree(esp);
}

static int esp_init_aead(struct xfrm_state *x)
{
	struct esp_data *esp = x->data;
	struct crypto_aead *aead;
	int err;

	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
	err = PTR_ERR(aead);
	if (IS_ERR(aead))
		goto error;

	esp->aead = aead;

	err = crypto_aead_setkey(aead, x->aead->alg_key,
				 (x->aead->alg_key_len + 7) / 8);
	if (err)
		goto error;

	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
	if (err)
		goto error;

error:
	return err;
}

static int esp_init_authenc(struct xfrm_state *x)
{
	struct esp_data *esp = x->data;
	struct crypto_aead *aead;
	struct crypto_authenc_key_param *param;
	struct rtattr *rta;
	char *key;
	char *p;
	char authenc_name[CRYPTO_MAX_ALG_NAME];
	unsigned int keylen;
	int err;

	err = -EINVAL;
	if (x->ealg == NULL)
		goto error;

	err = -ENAMETOOLONG;
	if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
		     x->aalg ? x->aalg->alg_name : "digest_null",
		     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
		goto error;

	aead = crypto_alloc_aead(authenc_name, 0, 0);
	err = PTR_ERR(aead);
	if (IS_ERR(aead))
		goto error;

	esp->aead = aead;

	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
	err = -ENOMEM;
	key = kmalloc(keylen, GFP_KERNEL);
	if (!key)
		goto error;

	p = key;
	rta = (void *)p;
	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
	rta->rta_len = RTA_LENGTH(sizeof(*param));
	param = RTA_DATA(rta);
	p += RTA_SPACE(sizeof(*param));

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

		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
		p += (x->aalg->alg_key_len + 7) / 8;

		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
		BUG_ON(!aalg_desc);

		err = -EINVAL;
		if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
		    crypto_aead_authsize(aead)) {
			NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
				 x->aalg->alg_name,
				 crypto_aead_authsize(aead),
				 aalg_desc->uinfo.auth.icv_fullbits/8);
			goto free_key;
		}

		err = crypto_aead_setauthsize(
			aead, x->aalg->alg_trunc_len / 8);
		if (err)
			goto free_key;
	}

	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);

	err = crypto_aead_setkey(aead, key, keylen);

free_key:
	kfree(key);

error:
	return err;
}

static int esp_init_state(struct xfrm_state *x)
{
	struct esp_data *esp;
	struct crypto_aead *aead;
	u32 align;
	int err;

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

	x->data = esp;

	if (x->aead)
		err = esp_init_aead(x);
	else
		err = esp_init_authenc(x);

	if (err)
		goto error;

	aead = esp->aead;

	esp->padlen = 0;

	x->props.header_len = sizeof(struct ip_esp_hdr) +
			      crypto_aead_ivsize(aead);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct iphdr);
	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
		x->props.header_len += IPV4_BEET_PHMAXLEN;
	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;
		}
	}

	align = ALIGN(crypto_aead_blocksize(aead), 4);
	if (esp->padlen)
		align = max_t(u32, align, esp->padlen);
	x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);

error:
	return err;
}

static const struct xfrm_type esp_type =
{
	.description	= "ESP4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_ESP,
	.flags		= XFRM_TYPE_REPLAY_PROT,
	.init_state	= esp_init_state,
	.destructor	= esp_destroy,
	.get_mtu	= esp4_get_mtu,
	.input		= esp_input,
	.output		= esp_output
};

static const struct net_protocol esp4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	esp4_err,
	.no_policy	=	1,
	.netns_ok	=	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");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
Commit	Line	Data
38320c70 HX	1	#include <crypto/aead.h>
38320c70 HX	2	#include <crypto/authenc.h>
6b7326c8	3	#include <linux/err.h>
1da177e4 LT	4	#include <linux/module.h>
	5	#include <net/ip.h>
	6	#include <net/xfrm.h>
	7	#include <net/esp.h>
72998d8c	8	#include <linux/scatterlist.h>
a02a6422	9	#include <linux/kernel.h>
1da177e4	10	#include <linux/pfkeyv2.h>
38320c70 HX	11	#include <linux/rtnetlink.h>
38320c70 HX	12	#include <linux/slab.h>
b7c6538c	13	#include <linux/spinlock.h>
2017a72c	14	#include <linux/in6.h>
1da177e4	15	#include <net/icmp.h>
14c85021	16	#include <net/protocol.h>
1da177e4 LT	17	#include <net/udp.h>
1da177e4 LT	18
38320c70 HX	19	struct esp_skb_cb {
	20	struct xfrm_skb_cb xfrm;
	21	void *tmp;
	22	};
	23
	24	#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
	25
	26	/*
	27	* Allocate an AEAD request structure with extra space for SG and IV.
	28	*
	29	* For alignment considerations the IV is placed at the front, followed
	30	* by the request and finally the SG list.
	31	*
	32	* TODO: Use spare space in skb for this where possible.
	33	*/
	34	static void esp_alloc_tmp(struct crypto_aead aead, int nfrags)
	35	{
	36	unsigned int len;
	37
	38	len = crypto_aead_ivsize(aead);
	39	if (len) {
	40	len += crypto_aead_alignmask(aead) &
	41	~(crypto_tfm_ctx_alignment() - 1);
	42	len = ALIGN(len, crypto_tfm_ctx_alignment());
	43	}
	44
	45	len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
	46	len = ALIGN(len, __alignof__(struct scatterlist));
	47
	48	len += sizeof(struct scatterlist) * nfrags;
	49
	50	return kmalloc(len, GFP_ATOMIC);
	51	}
	52
	53	static inline u8 esp_tmp_iv(struct crypto_aead aead, void *tmp)
	54	{
	55	return crypto_aead_ivsize(aead) ?
	56	PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
	57	}
	58
	59	static inline struct aead_givcrypt_request *esp_tmp_givreq(
	60	struct crypto_aead aead, u8 iv)
	61	{
	62	struct aead_givcrypt_request *req;
	63
	64	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
	65	crypto_tfm_ctx_alignment());
	66	aead_givcrypt_set_tfm(req, aead);
	67	return req;
	68	}
	69
	70	static inline struct aead_request esp_tmp_req(struct crypto_aead aead, u8 *iv)
	71	{
	72	struct aead_request *req;
	73
	74	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
	75	crypto_tfm_ctx_alignment());
	76	aead_request_set_tfm(req, aead);
	77	return req;
	78	}
	79
	80	static inline struct scatterlist esp_req_sg(struct crypto_aead aead,
	81	struct aead_request *req)
	82	{
83	return (void *)ALIGN((unsigned long)(req + 1) +
84	crypto_aead_reqsize(aead),
85	__alignof__(struct scatterlist));
86	}
87
88	static inline struct scatterlist *esp_givreq_sg(
89	struct crypto_aead aead, struct aead_givcrypt_request req)
90	{
91	return (void *)ALIGN((unsigned long)(req + 1) +
92	crypto_aead_reqsize(aead),
93	__alignof__(struct scatterlist));
94	}
95
96	static void esp_output_done(struct crypto_async_request *base, int err)
97	{
98	struct sk_buff *skb = base->data;
99
100	kfree(ESP_SKB_CB(skb)->tmp);
101	xfrm_output_resume(skb, err);
102	}
103
1da177e4 LT	104	static int esp_output(struct xfrm_state x, struct sk_buff skb)
	105	{
	106	int err;
1da177e4	107	struct ip_esp_hdr *esph;
38320c70 HX	108	struct crypto_aead *aead;
	109	struct aead_givcrypt_request *req;
	110	struct scatterlist *sg;
	111	struct scatterlist *asg;
1da177e4 LT	112	struct esp_data *esp;
1da177e4 LT	113	struct sk_buff *trailer;
38320c70 HX	114	void *tmp;
38320c70 HX	115	u8 *iv;
27a884dc	116	u8 *tail;
1da177e4 LT	117	int blksize;
	118	int clen;
	119	int alen;
	120	int nfrags;
	121
7b277b1a	122	/* skb is pure payload to encrypt */
1da177e4 LT	123
	124	err = -ENOMEM;
	125
	126	/* Round to block size */
	127	clen = skb->len;
	128
	129	esp = x->data;
38320c70 HX	130	aead = esp->aead;
	131	alen = crypto_aead_authsize(aead);
	132
	133	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
a02a6422	134	clen = ALIGN(clen + 2, blksize);
38320c70 HX	135	if (esp->padlen)
	136	clen = ALIGN(clen, esp->padlen);
	137
	138	if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
	139	goto error;
	140	nfrags = err;
1da177e4	141
38320c70 HX	142	tmp = esp_alloc_tmp(aead, nfrags + 1);
38320c70 HX	143	if (!tmp)
1da177e4 LT	144	goto error;
1da177e4 LT	145
38320c70 HX	146	iv = esp_tmp_iv(aead, tmp);
	147	req = esp_tmp_givreq(aead, iv);
	148	asg = esp_givreq_sg(aead, req);
	149	sg = asg + 1;
	150
1da177e4	151	/* Fill padding... */
27a884dc	152	tail = skb_tail_pointer(trailer);
1da177e4 LT	153	do {
	154	int i;
	155	for (i=0; i<clen-skb->len - 2; i++)
27a884dc	156	tail[i] = i + 1;
1da177e4	157	} while (0);
27a884dc	158	tail[clen - skb->len - 2] = (clen - skb->len) - 2;
38320c70 HX	159	tail[clen - skb->len - 1] = *skb_mac_header(skb);
38320c70 HX	160	pskb_put(skb, trailer, clen - skb->len + alen);
1da177e4	161
7b277b1a	162	skb_push(skb, -skb_network_offset(skb));
87bdc48d	163	esph = ip_esp_hdr(skb);
37fedd3a	164	*skb_mac_header(skb) = IPPROTO_ESP;
1da177e4 LT	165
	166	/* this is non-NULL only with UDP Encapsulation */
	167	if (x->encap) {
	168	struct xfrm_encap_tmpl *encap = x->encap;
	169	struct udphdr *uh;
d5a0a1e3	170	__be32 *udpdata32;
5e226e4d	171	__be16 sport, dport;
38320c70 HX	172	int encap_type;
	173
	174	spin_lock_bh(&x->lock);
	175	sport = encap->encap_sport;
	176	dport = encap->encap_dport;
	177	encap_type = encap->encap_type;
	178	spin_unlock_bh(&x->lock);
1da177e4 LT	179
1da177e4 LT	180	uh = (struct udphdr *)esph;
38320c70 HX	181	uh->source = sport;
	182	uh->dest = dport;
	183	uh->len = htons(skb->len - skb_transport_offset(skb));
1da177e4 LT	184	uh->check = 0;
1da177e4 LT	185
38320c70	186	switch (encap_type) {
1da177e4 LT	187	default:
	188	case UDP_ENCAP_ESPINUDP:
	189	esph = (struct ip_esp_hdr *)(uh + 1);
	190	break;
	191	case UDP_ENCAP_ESPINUDP_NON_IKE:
d5a0a1e3	192	udpdata32 = (__be32 *)(uh + 1);
1da177e4 LT	193	udpdata32[0] = udpdata32[1] = 0;
	194	esph = (struct ip_esp_hdr *)(udpdata32 + 2);
	195	break;
	196	}
	197
37fedd3a HX	198	*skb_mac_header(skb) = IPPROTO_UDP;
37fedd3a HX	199	}
1da177e4 LT	200
1da177e4 LT	201	esph->spi = x->id.spi;
b318e0e4	202	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
1da177e4	203
38320c70 HX	204	sg_init_table(sg, nfrags);
	205	skb_to_sgvec(skb, sg,
	206	esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
	207	clen + alen);
	208	sg_init_one(asg, esph, sizeof(*esph));
	209
	210	aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
	211	aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
	212	aead_givcrypt_set_assoc(req, asg, sizeof(*esph));
b318e0e4 HX	213	aead_givcrypt_set_giv(req, esph->enc_data,
b318e0e4 HX	214	XFRM_SKB_CB(skb)->seq.output);
38320c70 HX	215
	216	ESP_SKB_CB(skb)->tmp = tmp;
	217	err = crypto_aead_givencrypt(req);
	218	if (err == -EINPROGRESS)
	219	goto error;
1da177e4	220
38320c70 HX	221	if (err == -EBUSY)
38320c70 HX	222	err = NET_XMIT_DROP;
1da177e4	223
38320c70	224	kfree(tmp);
b7c6538c	225
1da177e4 LT	226	error:
	227	return err;
	228	}
	229
38320c70	230	static int esp_input_done2(struct sk_buff *skb, int err)
1da177e4 LT	231	{
1da177e4 LT	232	struct iphdr *iph;
38320c70	233	struct xfrm_state *x = xfrm_input_state(skb);
1da177e4	234	struct esp_data *esp = x->data;
38320c70 HX	235	struct crypto_aead *aead = esp->aead;
	236	int alen = crypto_aead_authsize(aead);
	237	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
	238	int elen = skb->len - hlen;
31a4ab93	239	int ihl;
4bf05ece	240	u8 nexthdr[2];
4bf05ece	241	int padlen;
1da177e4	242
38320c70	243	kfree(ESP_SKB_CB(skb)->tmp);
0ebea8ef	244
6b7326c8	245	if (unlikely(err))
668dc8af	246	goto out;
1da177e4	247
4bf05ece HX	248	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
4bf05ece HX	249	BUG();
1da177e4	250
668dc8af	251	err = -EINVAL;
4bf05ece	252	padlen = nexthdr[0];
38320c70	253	if (padlen + 2 + alen >= elen)
4bf05ece	254	goto out;
1da177e4	255
e905a9ed	256	/* ... check padding bits here. Silly. :-) */
1da177e4	257
eddc9ec5	258	iph = ip_hdr(skb);
31a4ab93 HX	259	ihl = iph->ihl * 4;
31a4ab93 HX	260
752c1f4c HX	261	if (x->encap) {
752c1f4c HX	262	struct xfrm_encap_tmpl *encap = x->encap;
d56f90a7	263	struct udphdr uh = (void )(skb_network_header(skb) + ihl);
752c1f4c HX	264
	265	/*
	266	* 1) if the NAT-T peer's IP or port changed then
	267	* advertize the change to the keying daemon.
	268	* This is an inbound SA, so just compare
	269	* SRC ports.
	270	*/
	271	if (iph->saddr != x->props.saddr.a4 \|\|
	272	uh->source != encap->encap_sport) {
	273	xfrm_address_t ipaddr;
	274
	275	ipaddr.a4 = iph->saddr;
	276	km_new_mapping(x, &ipaddr, uh->source);
e905a9ed	277
752c1f4c HX	278	/* XXX: perhaps add an extra
	279	* policy check here, to see
	280	* if we should allow or
	281	* reject a packet from a
	282	* different source
	283	* address/port.
	284	*/
1da177e4	285	}
e905a9ed	286
752c1f4c HX	287	/*
	288	* 2) ignore UDP/TCP checksums in case
	289	* of NAT-T in Transport Mode, or
	290	* perform other post-processing fixes
	291	* as per draft-ietf-ipsec-udp-encaps-06,
	292	* section 3.1.2
	293	*/
8bd17075	294	if (x->props.mode == XFRM_MODE_TRANSPORT)
752c1f4c	295	skb->ip_summed = CHECKSUM_UNNECESSARY;
1da177e4 LT	296	}
1da177e4 LT	297
4bf05ece	298	pskb_trim(skb, skb->len - alen - padlen - 2);
38320c70	299	__skb_pull(skb, hlen);
967b05f6	300	skb_set_transport_header(skb, -ihl);
4bf05ece	301
38320c70 HX	302	err = nexthdr[1];
	303
	304	/* RFC4303: Drop dummy packets without any error */
	305	if (err == IPPROTO_NONE)
	306	err = -EINVAL;
	307
	308	out:
	309	return err;
	310	}
	311
	312	static void esp_input_done(struct crypto_async_request *base, int err)
	313	{
	314	struct sk_buff *skb = base->data;
	315
	316	xfrm_input_resume(skb, esp_input_done2(skb, err));
	317	}
	318
	319	/*
	320	* Note: detecting truncated vs. non-truncated authentication data is very
	321	* expensive, so we only support truncated data, which is the recommended
	322	* and common case.
	323	*/
	324	static int esp_input(struct xfrm_state x, struct sk_buff skb)
	325	{
	326	struct ip_esp_hdr *esph;
	327	struct esp_data *esp = x->data;
	328	struct crypto_aead *aead = esp->aead;
	329	struct aead_request *req;
	330	struct sk_buff *trailer;
	331	int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
	332	int nfrags;
	333	void *tmp;
	334	u8 *iv;
	335	struct scatterlist *sg;
	336	struct scatterlist *asg;
	337	int err = -EINVAL;
	338
920fc941	339	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
38320c70 HX	340	goto out;
	341
	342	if (elen <= 0)
	343	goto out;
	344
	345	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	346	goto out;
	347	nfrags = err;
	348
	349	err = -ENOMEM;
	350	tmp = esp_alloc_tmp(aead, nfrags + 1);
	351	if (!tmp)
	352	goto out;
	353
	354	ESP_SKB_CB(skb)->tmp = tmp;
	355	iv = esp_tmp_iv(aead, tmp);
	356	req = esp_tmp_req(aead, iv);
	357	asg = esp_req_sg(aead, req);
	358	sg = asg + 1;
	359
	360	skb->ip_summed = CHECKSUM_NONE;
	361
	362	esph = (struct ip_esp_hdr *)skb->data;
	363
	364	/* Get ivec. This can be wrong, check against another impls. */
	365	iv = esph->enc_data;
	366
	367	sg_init_table(sg, nfrags);
	368	skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
	369	sg_init_one(asg, esph, sizeof(*esph));
	370
	371	aead_request_set_callback(req, 0, esp_input_done, skb);
	372	aead_request_set_crypt(req, sg, sg, elen, iv);
	373	aead_request_set_assoc(req, asg, sizeof(*esph));
	374
	375	err = crypto_aead_decrypt(req);
	376	if (err == -EINPROGRESS)
	377	goto out;
	378
	379	err = esp_input_done2(skb, err);
1da177e4 LT	380
1da177e4 LT	381	out:
668dc8af	382	return err;
1da177e4 LT	383	}
1da177e4 LT	384
c5c25238	385	static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
1da177e4 LT	386	{
1da177e4 LT	387	struct esp_data *esp = x->data;
38320c70 HX	388	u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
38320c70 HX	389	u32 align = max_t(u32, blksize, esp->padlen);
c5c25238 PM	390	u32 rem;
c5c25238 PM	391
38320c70	392	mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
c5c25238 PM	393	rem = mtu & (align - 1);
c5c25238 PM	394	mtu &= ~(align - 1);
0a69452c DB	395
	396	switch (x->props.mode) {
	397	case XFRM_MODE_TUNNEL:
0a69452c DB	398	break;
	399	default:
	400	case XFRM_MODE_TRANSPORT:
	401	/* The worst case */
c5c25238 PM	402	mtu -= blksize - 4;
c5c25238 PM	403	mtu += min_t(u32, blksize - 4, rem);
0a69452c DB	404	break;
0a69452c DB	405	case XFRM_MODE_BEET:
e905a9ed	406	/* The worst case. */
c5c25238	407	mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
0a69452c	408	break;
1da177e4	409	}
0a69452c	410
c5c25238	411	return mtu - 2;
1da177e4 LT	412	}
	413
	414	static void esp4_err(struct sk_buff *skb, u32 info)
	415	{
4fb236ba	416	struct net *net = dev_net(skb->dev);
d9319100 JK	417	struct iphdr iph = (struct iphdr )skb->data;
d9319100 JK	418	struct ip_esp_hdr esph = (struct ip_esp_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	419	struct xfrm_state *x;
1da177e4 LT	420
88c7664f ACM	421	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	422	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	423	return;
1da177e4 LT	424
bd55775c	425	x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
1da177e4 LT	426	if (!x)
1da177e4 LT	427	return;
64ce2073 PM	428	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
64ce2073 PM	429	ntohl(esph->spi), ntohl(iph->daddr));
1da177e4 LT	430	xfrm_state_put(x);
	431	}
	432
	433	static void esp_destroy(struct xfrm_state *x)
	434	{
	435	struct esp_data *esp = x->data;
	436
	437	if (!esp)
	438	return;
	439
38320c70	440	crypto_free_aead(esp->aead);
1da177e4 LT	441	kfree(esp);
	442	}
	443
1a6509d9	444	static int esp_init_aead(struct xfrm_state *x)
1da177e4	445	{
1a6509d9 HX	446	struct esp_data *esp = x->data;
	447	struct crypto_aead *aead;
	448	int err;
	449
	450	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
	451	err = PTR_ERR(aead);
	452	if (IS_ERR(aead))
	453	goto error;
	454
	455	esp->aead = aead;
	456
	457	err = crypto_aead_setkey(aead, x->aead->alg_key,
	458	(x->aead->alg_key_len + 7) / 8);
	459	if (err)
	460	goto error;
	461
	462	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
	463	if (err)
	464	goto error;
	465
	466	error:
	467	return err;
	468	}
	469
	470	static int esp_init_authenc(struct xfrm_state *x)
	471	{
	472	struct esp_data *esp = x->data;
38320c70 HX	473	struct crypto_aead *aead;
	474	struct crypto_authenc_key_param *param;
	475	struct rtattr *rta;
	476	char *key;
	477	char *p;
	478	char authenc_name[CRYPTO_MAX_ALG_NAME];
38320c70 HX	479	unsigned int keylen;
38320c70 HX	480	int err;
1da177e4	481
1a6509d9	482	err = -EINVAL;
1da177e4	483	if (x->ealg == NULL)
1a6509d9	484	goto error;
38320c70	485
1a6509d9	486	err = -ENAMETOOLONG;
38320c70 HX	487	if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
	488	x->aalg ? x->aalg->alg_name : "digest_null",
	489	x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
1a6509d9	490	goto error;
38320c70 HX	491
	492	aead = crypto_alloc_aead(authenc_name, 0, 0);
	493	err = PTR_ERR(aead);
	494	if (IS_ERR(aead))
	495	goto error;
	496
	497	esp->aead = aead;
	498
	499	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
	500	(x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
	501	err = -ENOMEM;
	502	key = kmalloc(keylen, GFP_KERNEL);
	503	if (!key)
	504	goto error;
	505
	506	p = key;
	507	rta = (void *)p;
	508	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
	509	rta->rta_len = RTA_LENGTH(sizeof(*param));
	510	param = RTA_DATA(rta);
	511	p += RTA_SPACE(sizeof(*param));
	512
1da177e4 LT	513	if (x->aalg) {
	514	struct xfrm_algo_desc *aalg_desc;
	515
38320c70 HX	516	memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
38320c70 HX	517	p += (x->aalg->alg_key_len + 7) / 8;
1da177e4 LT	518
	519	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	520	BUG_ON(!aalg_desc);
	521
38320c70	522	err = -EINVAL;
1da177e4	523	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
38320c70	524	crypto_aead_authsize(aead)) {
64ce2073 PM	525	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
64ce2073 PM	526	x->aalg->alg_name,
38320c70	527	crypto_aead_authsize(aead),
64ce2073	528	aalg_desc->uinfo.auth.icv_fullbits/8);
38320c70	529	goto free_key;
1da177e4 LT	530	}
1da177e4 LT	531
38320c70	532	err = crypto_aead_setauthsize(
8f8a088c	533	aead, x->aalg->alg_trunc_len / 8);
38320c70 HX	534	if (err)
38320c70 HX	535	goto free_key;
1da177e4	536	}
4b7137ff	537
38320c70 HX	538	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
	539	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
	540
	541	err = crypto_aead_setkey(aead, key, keylen);
	542
	543	free_key:
	544	kfree(key);
	545
1a6509d9 HX	546	error:
	547	return err;
	548	}
	549
	550	static int esp_init_state(struct xfrm_state *x)
	551	{
	552	struct esp_data *esp;
	553	struct crypto_aead *aead;
	554	u32 align;
	555	int err;
	556
	557	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
	558	if (esp == NULL)
	559	return -ENOMEM;
	560
	561	x->data = esp;
	562
	563	if (x->aead)
	564	err = esp_init_aead(x);
	565	else
	566	err = esp_init_authenc(x);
	567
38320c70	568	if (err)
1da177e4	569	goto error;
38320c70	570
1a6509d9 HX	571	aead = esp->aead;
	572
	573	esp->padlen = 0;
	574
38320c70 HX	575	x->props.header_len = sizeof(struct ip_esp_hdr) +
38320c70 HX	576	crypto_aead_ivsize(aead);
7e49e6de	577	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4	578	x->props.header_len += sizeof(struct iphdr);
eb49e630	579	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
ac758e3c	580	x->props.header_len += IPV4_BEET_PHMAXLEN;
1da177e4 LT	581	if (x->encap) {
	582	struct xfrm_encap_tmpl *encap = x->encap;
	583
	584	switch (encap->encap_type) {
	585	default:
	586	goto error;
	587	case UDP_ENCAP_ESPINUDP:
	588	x->props.header_len += sizeof(struct udphdr);
	589	break;
	590	case UDP_ENCAP_ESPINUDP_NON_IKE:
	591	x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
	592	break;
	593	}
	594	}
38320c70 HX	595
	596	align = ALIGN(crypto_aead_blocksize(aead), 4);
	597	if (esp->padlen)
	598	align = max_t(u32, align, esp->padlen);
	599	x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
1da177e4 LT	600
1da177e4 LT	601	error:
38320c70	602	return err;
1da177e4 LT	603	}
1da177e4 LT	604
533cb5b0	605	static const struct xfrm_type esp_type =
1da177e4 LT	606	{
	607	.description = "ESP4",
	608	.owner = THIS_MODULE,
	609	.proto = IPPROTO_ESP,
436a0a40	610	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	611	.init_state = esp_init_state,
1da177e4 LT	612	.destructor = esp_destroy,
c5c25238	613	.get_mtu = esp4_get_mtu,
1da177e4	614	.input = esp_input,
1da177e4 LT	615	.output = esp_output
	616	};
	617
32613090	618	static const struct net_protocol esp4_protocol = {
1da177e4 LT	619	.handler = xfrm4_rcv,
	620	.err_handler = esp4_err,
	621	.no_policy = 1,
4fb236ba	622	.netns_ok = 1,
1da177e4 LT	623	};
	624
	625	static int __init esp4_init(void)
	626	{
1da177e4 LT	627	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
	628	printk(KERN_INFO "ip esp init: can't add xfrm type\n");
	629	return -EAGAIN;
	630	}
	631	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
	632	printk(KERN_INFO "ip esp init: can't add protocol\n");
	633	xfrm_unregister_type(&esp_type, AF_INET);
	634	return -EAGAIN;
	635	}
	636	return 0;
	637	}
	638
	639	static void __exit esp4_fini(void)
	640	{
	641	if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
	642	printk(KERN_INFO "ip esp close: can't remove protocol\n");
	643	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
	644	printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
	645	}
	646
	647	module_init(esp4_init);
	648	module_exit(esp4_fini);
	649	MODULE_LICENSE("GPL");
d3d6dd3a	650	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);