[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]))

static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);

/*
 * 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 plen;
	int tfclen;
	int nfrags;

	/* skb is pure payload to encrypt */

	err = -ENOMEM;

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

	tfclen = 0;
	if (x->tfcpad) {
		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
		u32 padto;

		padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
		if (skb->len < padto)
			tfclen = padto - skb->len;
	}
	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
	clen = ALIGN(skb->len + 2 + tfclen, blksize);
	if (esp->padlen)
		clen = ALIGN(clen, esp->padlen);
	plen = clen - skb->len - tfclen;

	err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
	if (err < 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);
	if (tfclen) {
		memset(tail, 0, tfclen);
		tail += tfclen;
	}
	do {
		int i;
		for (i = 0; i < plen - 2; i++)
			tail[i] = i + 1;
	} while (0);
	tail[plen - 2] = plen - 2;
	tail[plen - 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
d979e20f MW	26	static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
d979e20f MW	27
38320c70 HX	28	/*
	29	* Allocate an AEAD request structure with extra space for SG and IV.
	30	*
	31	* For alignment considerations the IV is placed at the front, followed
	32	* by the request and finally the SG list.
	33	*
	34	* TODO: Use spare space in skb for this where possible.
	35	*/
	36	static void esp_alloc_tmp(struct crypto_aead aead, int nfrags)
	37	{
	38	unsigned int len;
	39
	40	len = crypto_aead_ivsize(aead);
	41	if (len) {
	42	len += crypto_aead_alignmask(aead) &
	43	~(crypto_tfm_ctx_alignment() - 1);
	44	len = ALIGN(len, crypto_tfm_ctx_alignment());
	45	}
	46
	47	len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
	48	len = ALIGN(len, __alignof__(struct scatterlist));
	49
	50	len += sizeof(struct scatterlist) * nfrags;
	51
	52	return kmalloc(len, GFP_ATOMIC);
	53	}
	54
	55	static inline u8 esp_tmp_iv(struct crypto_aead aead, void *tmp)
	56	{
	57	return crypto_aead_ivsize(aead) ?
	58	PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
	59	}
	60
	61	static inline struct aead_givcrypt_request *esp_tmp_givreq(
	62	struct crypto_aead aead, u8 iv)
	63	{
	64	struct aead_givcrypt_request *req;
	65
	66	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
	67	crypto_tfm_ctx_alignment());
	68	aead_givcrypt_set_tfm(req, aead);
	69	return req;
	70	}
	71
	72	static inline struct aead_request esp_tmp_req(struct crypto_aead aead, u8 *iv)
	73	{
	74	struct aead_request *req;
	75
	76	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
	77	crypto_tfm_ctx_alignment());
	78	aead_request_set_tfm(req, aead);
	79	return req;
	80	}
	81
	82	static inline struct scatterlist esp_req_sg(struct crypto_aead aead,
	83	struct aead_request *req)
	84	{
	85	return (void *)ALIGN((unsigned long)(req + 1) +
	86	crypto_aead_reqsize(aead),
	87	__alignof__(struct scatterlist));
	88	}
	89
	90	static inline struct scatterlist *esp_givreq_sg(
	91	struct crypto_aead aead, struct aead_givcrypt_request req)
92	{
93	return (void *)ALIGN((unsigned long)(req + 1) +
94	crypto_aead_reqsize(aead),
95	__alignof__(struct scatterlist));
96	}
97
98	static void esp_output_done(struct crypto_async_request *base, int err)
99	{
100	struct sk_buff *skb = base->data;
101
102	kfree(ESP_SKB_CB(skb)->tmp);
103	xfrm_output_resume(skb, err);
104	}
105
1da177e4 LT	106	static int esp_output(struct xfrm_state x, struct sk_buff skb)
	107	{
	108	int err;
1da177e4	109	struct ip_esp_hdr *esph;
38320c70 HX	110	struct crypto_aead *aead;
	111	struct aead_givcrypt_request *req;
	112	struct scatterlist *sg;
	113	struct scatterlist *asg;
1da177e4 LT	114	struct esp_data *esp;
1da177e4 LT	115	struct sk_buff *trailer;
38320c70 HX	116	void *tmp;
38320c70 HX	117	u8 *iv;
27a884dc	118	u8 *tail;
1da177e4 LT	119	int blksize;
	120	int clen;
	121	int alen;
d979e20f MW	122	int plen;
d979e20f MW	123	int tfclen;
1da177e4 LT	124	int nfrags;
1da177e4 LT	125
7b277b1a	126	/* skb is pure payload to encrypt */
1da177e4 LT	127
	128	err = -ENOMEM;
	129
1da177e4	130	esp = x->data;
38320c70 HX	131	aead = esp->aead;
	132	alen = crypto_aead_authsize(aead);
	133
d979e20f MW	134	tfclen = 0;
	135	if (x->tfcpad) {
	136	struct xfrm_dst dst = (struct xfrm_dst )skb_dst(skb);
	137	u32 padto;
	138
	139	padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
	140	if (skb->len < padto)
	141	tfclen = padto - skb->len;
	142	}
38320c70	143	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
d979e20f	144	clen = ALIGN(skb->len + 2 + tfclen, blksize);
38320c70 HX	145	if (esp->padlen)
38320c70 HX	146	clen = ALIGN(clen, esp->padlen);
d979e20f	147	plen = clen - skb->len - tfclen;
38320c70	148
d979e20f MW	149	err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
d979e20f MW	150	if (err < 0)
38320c70 HX	151	goto error;
38320c70 HX	152	nfrags = err;
1da177e4	153
38320c70 HX	154	tmp = esp_alloc_tmp(aead, nfrags + 1);
38320c70 HX	155	if (!tmp)
1da177e4 LT	156	goto error;
1da177e4 LT	157
38320c70 HX	158	iv = esp_tmp_iv(aead, tmp);
	159	req = esp_tmp_givreq(aead, iv);
	160	asg = esp_givreq_sg(aead, req);
	161	sg = asg + 1;
	162
1da177e4	163	/* Fill padding... */
27a884dc	164	tail = skb_tail_pointer(trailer);
d979e20f MW	165	if (tfclen) {
	166	memset(tail, 0, tfclen);
	167	tail += tfclen;
	168	}
1da177e4 LT	169	do {
1da177e4 LT	170	int i;
d979e20f	171	for (i = 0; i < plen - 2; i++)
27a884dc	172	tail[i] = i + 1;
1da177e4	173	} while (0);
d979e20f MW	174	tail[plen - 2] = plen - 2;
d979e20f MW	175	tail[plen - 1] = *skb_mac_header(skb);
38320c70	176	pskb_put(skb, trailer, clen - skb->len + alen);
1da177e4	177
7b277b1a	178	skb_push(skb, -skb_network_offset(skb));
87bdc48d	179	esph = ip_esp_hdr(skb);
37fedd3a	180	*skb_mac_header(skb) = IPPROTO_ESP;
1da177e4 LT	181
	182	/* this is non-NULL only with UDP Encapsulation */
	183	if (x->encap) {
	184	struct xfrm_encap_tmpl *encap = x->encap;
	185	struct udphdr *uh;
d5a0a1e3	186	__be32 *udpdata32;
5e226e4d	187	__be16 sport, dport;
38320c70 HX	188	int encap_type;
	189
	190	spin_lock_bh(&x->lock);
	191	sport = encap->encap_sport;
	192	dport = encap->encap_dport;
	193	encap_type = encap->encap_type;
	194	spin_unlock_bh(&x->lock);
1da177e4 LT	195
1da177e4 LT	196	uh = (struct udphdr *)esph;
38320c70 HX	197	uh->source = sport;
	198	uh->dest = dport;
	199	uh->len = htons(skb->len - skb_transport_offset(skb));
1da177e4 LT	200	uh->check = 0;
1da177e4 LT	201
38320c70	202	switch (encap_type) {
1da177e4 LT	203	default:
	204	case UDP_ENCAP_ESPINUDP:
	205	esph = (struct ip_esp_hdr *)(uh + 1);
	206	break;
	207	case UDP_ENCAP_ESPINUDP_NON_IKE:
d5a0a1e3	208	udpdata32 = (__be32 *)(uh + 1);
1da177e4 LT	209	udpdata32[0] = udpdata32[1] = 0;
	210	esph = (struct ip_esp_hdr *)(udpdata32 + 2);
	211	break;
	212	}
	213
37fedd3a HX	214	*skb_mac_header(skb) = IPPROTO_UDP;
37fedd3a HX	215	}
1da177e4 LT	216
1da177e4 LT	217	esph->spi = x->id.spi;
b318e0e4	218	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
1da177e4	219
38320c70 HX	220	sg_init_table(sg, nfrags);
	221	skb_to_sgvec(skb, sg,
	222	esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
	223	clen + alen);
	224	sg_init_one(asg, esph, sizeof(*esph));
	225
	226	aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
	227	aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
	228	aead_givcrypt_set_assoc(req, asg, sizeof(*esph));
b318e0e4 HX	229	aead_givcrypt_set_giv(req, esph->enc_data,
b318e0e4 HX	230	XFRM_SKB_CB(skb)->seq.output);
38320c70 HX	231
	232	ESP_SKB_CB(skb)->tmp = tmp;
	233	err = crypto_aead_givencrypt(req);
	234	if (err == -EINPROGRESS)
	235	goto error;
1da177e4	236
38320c70 HX	237	if (err == -EBUSY)
38320c70 HX	238	err = NET_XMIT_DROP;
1da177e4	239
38320c70	240	kfree(tmp);
b7c6538c	241
1da177e4 LT	242	error:
	243	return err;
	244	}
	245
38320c70	246	static int esp_input_done2(struct sk_buff *skb, int err)
1da177e4 LT	247	{
1da177e4 LT	248	struct iphdr *iph;
38320c70	249	struct xfrm_state *x = xfrm_input_state(skb);
1da177e4	250	struct esp_data *esp = x->data;
38320c70 HX	251	struct crypto_aead *aead = esp->aead;
	252	int alen = crypto_aead_authsize(aead);
	253	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
	254	int elen = skb->len - hlen;
31a4ab93	255	int ihl;
4bf05ece	256	u8 nexthdr[2];
4bf05ece	257	int padlen;
1da177e4	258
38320c70	259	kfree(ESP_SKB_CB(skb)->tmp);
0ebea8ef	260
6b7326c8	261	if (unlikely(err))
668dc8af	262	goto out;
1da177e4	263
4bf05ece HX	264	if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
4bf05ece HX	265	BUG();
1da177e4	266
668dc8af	267	err = -EINVAL;
4bf05ece	268	padlen = nexthdr[0];
38320c70	269	if (padlen + 2 + alen >= elen)
4bf05ece	270	goto out;
1da177e4	271
e905a9ed	272	/* ... check padding bits here. Silly. :-) */
1da177e4	273
eddc9ec5	274	iph = ip_hdr(skb);
31a4ab93 HX	275	ihl = iph->ihl * 4;
31a4ab93 HX	276
752c1f4c HX	277	if (x->encap) {
752c1f4c HX	278	struct xfrm_encap_tmpl *encap = x->encap;
d56f90a7	279	struct udphdr uh = (void )(skb_network_header(skb) + ihl);
752c1f4c HX	280
	281	/*
	282	* 1) if the NAT-T peer's IP or port changed then
	283	* advertize the change to the keying daemon.
	284	* This is an inbound SA, so just compare
	285	* SRC ports.
	286	*/
	287	if (iph->saddr != x->props.saddr.a4 \|\|
	288	uh->source != encap->encap_sport) {
	289	xfrm_address_t ipaddr;
	290
	291	ipaddr.a4 = iph->saddr;
	292	km_new_mapping(x, &ipaddr, uh->source);
e905a9ed	293
752c1f4c HX	294	/* XXX: perhaps add an extra
	295	* policy check here, to see
	296	* if we should allow or
	297	* reject a packet from a
	298	* different source
	299	* address/port.
	300	*/
1da177e4	301	}
e905a9ed	302
752c1f4c HX	303	/*
	304	* 2) ignore UDP/TCP checksums in case
	305	* of NAT-T in Transport Mode, or
	306	* perform other post-processing fixes
	307	* as per draft-ietf-ipsec-udp-encaps-06,
	308	* section 3.1.2
	309	*/
8bd17075	310	if (x->props.mode == XFRM_MODE_TRANSPORT)
752c1f4c	311	skb->ip_summed = CHECKSUM_UNNECESSARY;
1da177e4 LT	312	}
1da177e4 LT	313
4bf05ece	314	pskb_trim(skb, skb->len - alen - padlen - 2);
38320c70	315	__skb_pull(skb, hlen);
967b05f6	316	skb_set_transport_header(skb, -ihl);
4bf05ece	317
38320c70 HX	318	err = nexthdr[1];
	319
	320	/* RFC4303: Drop dummy packets without any error */
	321	if (err == IPPROTO_NONE)
	322	err = -EINVAL;
	323
	324	out:
	325	return err;
	326	}
	327
	328	static void esp_input_done(struct crypto_async_request *base, int err)
	329	{
	330	struct sk_buff *skb = base->data;
	331
	332	xfrm_input_resume(skb, esp_input_done2(skb, err));
	333	}
	334
	335	/*
	336	* Note: detecting truncated vs. non-truncated authentication data is very
	337	* expensive, so we only support truncated data, which is the recommended
	338	* and common case.
	339	*/
	340	static int esp_input(struct xfrm_state x, struct sk_buff skb)
	341	{
	342	struct ip_esp_hdr *esph;
	343	struct esp_data *esp = x->data;
	344	struct crypto_aead *aead = esp->aead;
	345	struct aead_request *req;
	346	struct sk_buff *trailer;
	347	int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
	348	int nfrags;
	349	void *tmp;
	350	u8 *iv;
	351	struct scatterlist *sg;
	352	struct scatterlist *asg;
	353	int err = -EINVAL;
	354
920fc941	355	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
38320c70 HX	356	goto out;
	357
	358	if (elen <= 0)
	359	goto out;
	360
	361	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	362	goto out;
	363	nfrags = err;
	364
	365	err = -ENOMEM;
	366	tmp = esp_alloc_tmp(aead, nfrags + 1);
	367	if (!tmp)
	368	goto out;
	369
	370	ESP_SKB_CB(skb)->tmp = tmp;
	371	iv = esp_tmp_iv(aead, tmp);
	372	req = esp_tmp_req(aead, iv);
	373	asg = esp_req_sg(aead, req);
	374	sg = asg + 1;
	375
	376	skb->ip_summed = CHECKSUM_NONE;
	377
	378	esph = (struct ip_esp_hdr *)skb->data;
	379
	380	/* Get ivec. This can be wrong, check against another impls. */
	381	iv = esph->enc_data;
	382
	383	sg_init_table(sg, nfrags);
	384	skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
	385	sg_init_one(asg, esph, sizeof(*esph));
	386
	387	aead_request_set_callback(req, 0, esp_input_done, skb);
	388	aead_request_set_crypt(req, sg, sg, elen, iv);
	389	aead_request_set_assoc(req, asg, sizeof(*esph));
	390
	391	err = crypto_aead_decrypt(req);
	392	if (err == -EINPROGRESS)
	393	goto out;
	394
	395	err = esp_input_done2(skb, err);
1da177e4 LT	396
1da177e4 LT	397	out:
668dc8af	398	return err;
1da177e4 LT	399	}
1da177e4 LT	400
c5c25238	401	static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
1da177e4 LT	402	{
1da177e4 LT	403	struct esp_data *esp = x->data;
38320c70 HX	404	u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
38320c70 HX	405	u32 align = max_t(u32, blksize, esp->padlen);
c5c25238 PM	406	u32 rem;
c5c25238 PM	407
38320c70	408	mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
c5c25238 PM	409	rem = mtu & (align - 1);
c5c25238 PM	410	mtu &= ~(align - 1);
0a69452c DB	411
	412	switch (x->props.mode) {
	413	case XFRM_MODE_TUNNEL:
0a69452c DB	414	break;
	415	default:
	416	case XFRM_MODE_TRANSPORT:
	417	/* The worst case */
c5c25238 PM	418	mtu -= blksize - 4;
c5c25238 PM	419	mtu += min_t(u32, blksize - 4, rem);
0a69452c DB	420	break;
0a69452c DB	421	case XFRM_MODE_BEET:
e905a9ed	422	/* The worst case. */
c5c25238	423	mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
0a69452c	424	break;
1da177e4	425	}
0a69452c	426
c5c25238	427	return mtu - 2;
1da177e4 LT	428	}
	429
	430	static void esp4_err(struct sk_buff *skb, u32 info)
	431	{
4fb236ba	432	struct net *net = dev_net(skb->dev);
d9319100 JK	433	struct iphdr iph = (struct iphdr )skb->data;
d9319100 JK	434	struct ip_esp_hdr esph = (struct ip_esp_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	435	struct xfrm_state *x;
1da177e4 LT	436
88c7664f ACM	437	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	438	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	439	return;
1da177e4 LT	440
bd55775c	441	x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
1da177e4 LT	442	if (!x)
1da177e4 LT	443	return;
64ce2073 PM	444	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
64ce2073 PM	445	ntohl(esph->spi), ntohl(iph->daddr));
1da177e4 LT	446	xfrm_state_put(x);
	447	}
	448
	449	static void esp_destroy(struct xfrm_state *x)
	450	{
	451	struct esp_data *esp = x->data;
	452
	453	if (!esp)
	454	return;
	455
38320c70	456	crypto_free_aead(esp->aead);
1da177e4 LT	457	kfree(esp);
	458	}
	459
1a6509d9	460	static int esp_init_aead(struct xfrm_state *x)
1da177e4	461	{
1a6509d9 HX	462	struct esp_data *esp = x->data;
	463	struct crypto_aead *aead;
	464	int err;
	465
	466	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
	467	err = PTR_ERR(aead);
	468	if (IS_ERR(aead))
	469	goto error;
	470
	471	esp->aead = aead;
	472
	473	err = crypto_aead_setkey(aead, x->aead->alg_key,
	474	(x->aead->alg_key_len + 7) / 8);
	475	if (err)
	476	goto error;
	477
	478	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
	479	if (err)
	480	goto error;
	481
	482	error:
	483	return err;
	484	}
	485
	486	static int esp_init_authenc(struct xfrm_state *x)
	487	{
	488	struct esp_data *esp = x->data;
38320c70 HX	489	struct crypto_aead *aead;
	490	struct crypto_authenc_key_param *param;
	491	struct rtattr *rta;
	492	char *key;
	493	char *p;
	494	char authenc_name[CRYPTO_MAX_ALG_NAME];
38320c70 HX	495	unsigned int keylen;
38320c70 HX	496	int err;
1da177e4	497
1a6509d9	498	err = -EINVAL;
1da177e4	499	if (x->ealg == NULL)
1a6509d9	500	goto error;
38320c70	501
1a6509d9	502	err = -ENAMETOOLONG;
38320c70 HX	503	if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
	504	x->aalg ? x->aalg->alg_name : "digest_null",
	505	x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
1a6509d9	506	goto error;
38320c70 HX	507
	508	aead = crypto_alloc_aead(authenc_name, 0, 0);
	509	err = PTR_ERR(aead);
	510	if (IS_ERR(aead))
	511	goto error;
	512
	513	esp->aead = aead;
	514
	515	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
	516	(x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
	517	err = -ENOMEM;
	518	key = kmalloc(keylen, GFP_KERNEL);
	519	if (!key)
	520	goto error;
	521
	522	p = key;
	523	rta = (void *)p;
	524	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
	525	rta->rta_len = RTA_LENGTH(sizeof(*param));
	526	param = RTA_DATA(rta);
	527	p += RTA_SPACE(sizeof(*param));
	528
1da177e4 LT	529	if (x->aalg) {
	530	struct xfrm_algo_desc *aalg_desc;
	531
38320c70 HX	532	memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
38320c70 HX	533	p += (x->aalg->alg_key_len + 7) / 8;
1da177e4 LT	534
	535	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	536	BUG_ON(!aalg_desc);
	537
38320c70	538	err = -EINVAL;
1da177e4	539	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
38320c70	540	crypto_aead_authsize(aead)) {
64ce2073 PM	541	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
64ce2073 PM	542	x->aalg->alg_name,
38320c70	543	crypto_aead_authsize(aead),
64ce2073	544	aalg_desc->uinfo.auth.icv_fullbits/8);
38320c70	545	goto free_key;
1da177e4 LT	546	}
1da177e4 LT	547
38320c70	548	err = crypto_aead_setauthsize(
8f8a088c	549	aead, x->aalg->alg_trunc_len / 8);
38320c70 HX	550	if (err)
38320c70 HX	551	goto free_key;
1da177e4	552	}
4b7137ff	553
38320c70 HX	554	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
	555	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
	556
	557	err = crypto_aead_setkey(aead, key, keylen);
	558
	559	free_key:
	560	kfree(key);
	561
1a6509d9 HX	562	error:
	563	return err;
	564	}
	565
	566	static int esp_init_state(struct xfrm_state *x)
	567	{
	568	struct esp_data *esp;
	569	struct crypto_aead *aead;
	570	u32 align;
	571	int err;
	572
	573	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
	574	if (esp == NULL)
	575	return -ENOMEM;
	576
	577	x->data = esp;
	578
	579	if (x->aead)
	580	err = esp_init_aead(x);
	581	else
	582	err = esp_init_authenc(x);
	583
38320c70	584	if (err)
1da177e4	585	goto error;
38320c70	586
1a6509d9 HX	587	aead = esp->aead;
	588
	589	esp->padlen = 0;
	590
38320c70 HX	591	x->props.header_len = sizeof(struct ip_esp_hdr) +
38320c70 HX	592	crypto_aead_ivsize(aead);
7e49e6de	593	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4	594	x->props.header_len += sizeof(struct iphdr);
eb49e630	595	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
ac758e3c	596	x->props.header_len += IPV4_BEET_PHMAXLEN;
1da177e4 LT	597	if (x->encap) {
	598	struct xfrm_encap_tmpl *encap = x->encap;
	599
	600	switch (encap->encap_type) {
	601	default:
	602	goto error;
	603	case UDP_ENCAP_ESPINUDP:
	604	x->props.header_len += sizeof(struct udphdr);
	605	break;
	606	case UDP_ENCAP_ESPINUDP_NON_IKE:
	607	x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
	608	break;
	609	}
	610	}
38320c70 HX	611
	612	align = ALIGN(crypto_aead_blocksize(aead), 4);
	613	if (esp->padlen)
	614	align = max_t(u32, align, esp->padlen);
	615	x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
1da177e4 LT	616
1da177e4 LT	617	error:
38320c70	618	return err;
1da177e4 LT	619	}
1da177e4 LT	620
533cb5b0	621	static const struct xfrm_type esp_type =
1da177e4 LT	622	{
	623	.description = "ESP4",
	624	.owner = THIS_MODULE,
	625	.proto = IPPROTO_ESP,
436a0a40	626	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	627	.init_state = esp_init_state,
1da177e4 LT	628	.destructor = esp_destroy,
c5c25238	629	.get_mtu = esp4_get_mtu,
1da177e4	630	.input = esp_input,
1da177e4 LT	631	.output = esp_output
	632	};
	633
32613090	634	static const struct net_protocol esp4_protocol = {
1da177e4 LT	635	.handler = xfrm4_rcv,
	636	.err_handler = esp4_err,
	637	.no_policy = 1,
4fb236ba	638	.netns_ok = 1,
1da177e4 LT	639	};
	640
	641	static int __init esp4_init(void)
	642	{
1da177e4 LT	643	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
	644	printk(KERN_INFO "ip esp init: can't add xfrm type\n");
	645	return -EAGAIN;
	646	}
	647	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
	648	printk(KERN_INFO "ip esp init: can't add protocol\n");
	649	xfrm_unregister_type(&esp_type, AF_INET);
	650	return -EAGAIN;
	651	}
	652	return 0;
	653	}
	654
	655	static void __exit esp4_fini(void)
	656	{
	657	if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
	658	printk(KERN_INFO "ip esp close: can't remove protocol\n");
	659	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
	660	printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
	661	}
	662
	663	module_init(esp4_init);
	664	module_exit(esp4_fini);
	665	MODULE_LICENSE("GPL");
d3d6dd3a	666	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);