[linux.git] / net / ipv4 / ah4.c

#define pr_fmt(fmt) "IPsec: " fmt

#include <crypto/algapi.h>
#include <crypto/hash.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/ah.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <linux/scatterlist.h>
#include <net/icmp.h>
#include <net/protocol.h>

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

#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))

static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
			  unsigned int size)
{
	unsigned int len;

	len = size + crypto_ahash_digestsize(ahash) +
	      (crypto_ahash_alignmask(ahash) &
	       ~(crypto_tfm_ctx_alignment() - 1));

	len = ALIGN(len, crypto_tfm_ctx_alignment());

	len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
	len = ALIGN(len, __alignof__(struct scatterlist));

	len += sizeof(struct scatterlist) * nfrags;

	return kmalloc(len, GFP_ATOMIC);
}

static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
{
	return tmp + offset;
}

static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
			     unsigned int offset)
{
	return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
}

static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
					       u8 *icv)
{
	struct ahash_request *req;

	req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
				crypto_tfm_ctx_alignment());

	ahash_request_set_tfm(req, ahash);

	return req;
}

static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
					     struct ahash_request *req)
{
	return (void *)ALIGN((unsigned long)(req + 1) +
			     crypto_ahash_reqsize(ahash),
			     __alignof__(struct scatterlist));
}

/* Clear mutable options and find final destination to substitute
 * into IP header for icv calculation. Options are already checked
 * for validity, so paranoia is not required. */

static int ip_clear_mutable_options(const struct iphdr *iph, __be32 *daddr)
{
	unsigned char *optptr = (unsigned char *)(iph+1);
	int  l = iph->ihl*4 - sizeof(struct iphdr);
	int  optlen;

	while (l > 0) {
		switch (*optptr) {
		case IPOPT_END:
			return 0;
		case IPOPT_NOOP:
			l--;
			optptr++;
			continue;
		}
		optlen = optptr[1];
		if (optlen<2 || optlen>l)
			return -EINVAL;
		switch (*optptr) {
		case IPOPT_SEC:
		case 0x85:	/* Some "Extended Security" crap. */
		case IPOPT_CIPSO:
		case IPOPT_RA:
		case 0x80|21:	/* RFC1770 */
			break;
		case IPOPT_LSRR:
		case IPOPT_SSRR:
			if (optlen < 6)
				return -EINVAL;
			memcpy(daddr, optptr+optlen-4, 4);
			/* Fall through */
		default:
			memset(optptr, 0, optlen);
		}
		l -= optlen;
		optptr += optlen;
	}
	return 0;
}

static void ah_output_done(struct crypto_async_request *base, int err)
{
	u8 *icv;
	struct iphdr *iph;
	struct sk_buff *skb = base->data;
	struct xfrm_state *x = skb_dst(skb)->xfrm;
	struct ah_data *ahp = x->data;
	struct iphdr *top_iph = ip_hdr(skb);
	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	int ihl = ip_hdrlen(skb);

	iph = AH_SKB_CB(skb)->tmp;
	icv = ah_tmp_icv(ahp->ahash, iph, ihl);
	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);

	top_iph->tos = iph->tos;
	top_iph->ttl = iph->ttl;
	top_iph->frag_off = iph->frag_off;
	if (top_iph->ihl != 5) {
		top_iph->daddr = iph->daddr;
		memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	}

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

static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	int nfrags;
	int ihl;
	u8 *icv;
	struct sk_buff *trailer;
	struct crypto_ahash *ahash;
	struct ahash_request *req;
	struct scatterlist *sg;
	struct iphdr *iph, *top_iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	int seqhi_len = 0;
	__be32 *seqhi;
	int sglists = 0;
	struct scatterlist *seqhisg;

	ahp = x->data;
	ahash = ahp->ahash;

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

	skb_push(skb, -skb_network_offset(skb));
	ah = ip_auth_hdr(skb);
	ihl = ip_hdrlen(skb);

	if (x->props.flags & XFRM_STATE_ESN) {
		sglists = 1;
		seqhi_len = sizeof(*seqhi);
	}
	err = -ENOMEM;
	iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
	if (!iph)
		goto out;
	seqhi = (__be32 *)((char *)iph + ihl);
	icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
	req = ah_tmp_req(ahash, icv);
	sg = ah_req_sg(ahash, req);
	seqhisg = sg + nfrags;

	memset(ah->auth_data, 0, ahp->icv_trunc_len);

	top_iph = ip_hdr(skb);

	iph->tos = top_iph->tos;
	iph->ttl = top_iph->ttl;
	iph->frag_off = top_iph->frag_off;

	if (top_iph->ihl != 5) {
		iph->daddr = top_iph->daddr;
		memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
		err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
		if (err)
			goto out_free;
	}

	ah->nexthdr = *skb_mac_header(skb);
	*skb_mac_header(skb) = IPPROTO_AH;

	top_iph->tos = 0;
	top_iph->tot_len = htons(skb->len);
	top_iph->frag_off = 0;
	top_iph->ttl = 0;
	top_iph->check = 0;

	if (x->props.flags & XFRM_STATE_ALIGN4)
		ah->hdrlen  = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
	else
		ah->hdrlen  = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;

	ah->reserved = 0;
	ah->spi = x->id.spi;
	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);

	sg_init_table(sg, nfrags + sglists);
	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	if (unlikely(err < 0))
		goto out_free;

	if (x->props.flags & XFRM_STATE_ESN) {
		/* Attach seqhi sg right after packet payload */
		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
		sg_set_buf(seqhisg, seqhi, seqhi_len);
	}
	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
	ahash_request_set_callback(req, 0, ah_output_done, skb);

	AH_SKB_CB(skb)->tmp = iph;

	err = crypto_ahash_digest(req);
	if (err) {
		if (err == -EINPROGRESS)
			goto out;

		if (err == -ENOSPC)
			err = NET_XMIT_DROP;
		goto out_free;
	}

	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);

	top_iph->tos = iph->tos;
	top_iph->ttl = iph->ttl;
	top_iph->frag_off = iph->frag_off;
	if (top_iph->ihl != 5) {
		top_iph->daddr = iph->daddr;
		memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	}

out_free:
	kfree(iph);
out:
	return err;
}

static void ah_input_done(struct crypto_async_request *base, int err)
{
	u8 *auth_data;
	u8 *icv;
	struct iphdr *work_iph;
	struct sk_buff *skb = base->data;
	struct xfrm_state *x = xfrm_input_state(skb);
	struct ah_data *ahp = x->data;
	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	int ihl = ip_hdrlen(skb);
	int ah_hlen = (ah->hdrlen + 2) << 2;

	if (err)
		goto out;

	work_iph = AH_SKB_CB(skb)->tmp;
	auth_data = ah_tmp_auth(work_iph, ihl);
	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);

	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
	if (err)
		goto out;

	err = ah->nexthdr;

	skb->network_header += ah_hlen;
	memcpy(skb_network_header(skb), work_iph, ihl);
	__skb_pull(skb, ah_hlen + ihl);

	if (x->props.mode == XFRM_MODE_TUNNEL)
		skb_reset_transport_header(skb);
	else
		skb_set_transport_header(skb, -ihl);
out:
	kfree(AH_SKB_CB(skb)->tmp);
	xfrm_input_resume(skb, err);
}

static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int ah_hlen;
	int ihl;
	int nexthdr;
	int nfrags;
	u8 *auth_data;
	u8 *icv;
	struct sk_buff *trailer;
	struct crypto_ahash *ahash;
	struct ahash_request *req;
	struct scatterlist *sg;
	struct iphdr *iph, *work_iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	int err = -ENOMEM;
	int seqhi_len = 0;
	__be32 *seqhi;
	int sglists = 0;
	struct scatterlist *seqhisg;

	if (!pskb_may_pull(skb, sizeof(*ah)))
		goto out;

	ah = (struct ip_auth_hdr *)skb->data;
	ahp = x->data;
	ahash = ahp->ahash;

	nexthdr = ah->nexthdr;
	ah_hlen = (ah->hdrlen + 2) << 2;

	if (x->props.flags & XFRM_STATE_ALIGN4) {
		if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
		    ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
			goto out;
	} else {
		if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
		    ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
			goto out;
	}

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_unclone(skb, GFP_ATOMIC))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;


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

	ah = (struct ip_auth_hdr *)skb->data;
	iph = ip_hdr(skb);
	ihl = ip_hdrlen(skb);

	if (x->props.flags & XFRM_STATE_ESN) {
		sglists = 1;
		seqhi_len = sizeof(*seqhi);
	}

	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
				ahp->icv_trunc_len + seqhi_len);
	if (!work_iph) {
		err = -ENOMEM;
		goto out;
	}

	seqhi = (__be32 *)((char *)work_iph + ihl);
	auth_data = ah_tmp_auth(seqhi, seqhi_len);
	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	req = ah_tmp_req(ahash, icv);
	sg = ah_req_sg(ahash, req);
	seqhisg = sg + nfrags;

	memcpy(work_iph, iph, ihl);
	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	memset(ah->auth_data, 0, ahp->icv_trunc_len);

	iph->ttl = 0;
	iph->tos = 0;
	iph->frag_off = 0;
	iph->check = 0;
	if (ihl > sizeof(*iph)) {
		__be32 dummy;
		err = ip_clear_mutable_options(iph, &dummy);
		if (err)
			goto out_free;
	}

	skb_push(skb, ihl);

	sg_init_table(sg, nfrags + sglists);
	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	if (unlikely(err < 0))
		goto out_free;

	if (x->props.flags & XFRM_STATE_ESN) {
		/* Attach seqhi sg right after packet payload */
		*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
		sg_set_buf(seqhisg, seqhi, seqhi_len);
	}
	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
	ahash_request_set_callback(req, 0, ah_input_done, skb);

	AH_SKB_CB(skb)->tmp = work_iph;

	err = crypto_ahash_digest(req);
	if (err) {
		if (err == -EINPROGRESS)
			goto out;

		goto out_free;
	}

	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
	if (err)
		goto out_free;

	skb->network_header += ah_hlen;
	memcpy(skb_network_header(skb), work_iph, ihl);
	__skb_pull(skb, ah_hlen + ihl);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		skb_reset_transport_header(skb);
	else
		skb_set_transport_header(skb, -ihl);

	err = nexthdr;

out_free:
	kfree (work_iph);
out:
	return err;
}

static int ah4_err(struct sk_buff *skb, u32 info)
{
	struct net *net = dev_net(skb->dev);
	const struct iphdr *iph = (const struct iphdr *)skb->data;
	struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	switch (icmp_hdr(skb)->type) {
	case ICMP_DEST_UNREACH:
		if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
			return 0;
	case ICMP_REDIRECT:
		break;
	default:
		return 0;
	}

	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
			      ah->spi, IPPROTO_AH, AF_INET);
	if (!x)
		return 0;

	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
		ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
	else
		ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
	xfrm_state_put(x);

	return 0;
}

static int ah_init_state(struct xfrm_state *x)
{
	struct ah_data *ahp = NULL;
	struct xfrm_algo_desc *aalg_desc;
	struct crypto_ahash *ahash;

	if (!x->aalg)
		goto error;

	if (x->encap)
		goto error;

	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
	if (!ahp)
		return -ENOMEM;

	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
	if (IS_ERR(ahash))
		goto error;

	ahp->ahash = ahash;
	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
				(x->aalg->alg_key_len + 7) / 8))
		goto error;

	/*
	 * Lookup the algorithm description maintained by xfrm_algo,
	 * verify crypto transform properties, and store information
	 * we need for AH processing.  This lookup cannot fail here
	 * after a successful crypto_alloc_ahash().
	 */
	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	BUG_ON(!aalg_desc);

	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
	    crypto_ahash_digestsize(ahash)) {
		pr_info("%s: %s digestsize %u != %hu\n",
			__func__, x->aalg->alg_name,
			crypto_ahash_digestsize(ahash),
			aalg_desc->uinfo.auth.icv_fullbits / 8);
		goto error;
	}

	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;

	if (x->props.flags & XFRM_STATE_ALIGN4)
		x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
						  ahp->icv_trunc_len);
	else
		x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
						  ahp->icv_trunc_len);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct iphdr);
	x->data = ahp;

	return 0;

error:
	if (ahp) {
		crypto_free_ahash(ahp->ahash);
		kfree(ahp);
	}
	return -EINVAL;
}

static void ah_destroy(struct xfrm_state *x)
{
	struct ah_data *ahp = x->data;

	if (!ahp)
		return;

	crypto_free_ahash(ahp->ahash);
	kfree(ahp);
}

static int ah4_rcv_cb(struct sk_buff *skb, int err)
{
	return 0;
}

static const struct xfrm_type ah_type =
{
	.description	= "AH4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_AH,
	.flags		= XFRM_TYPE_REPLAY_PROT,
	.init_state	= ah_init_state,
	.destructor	= ah_destroy,
	.input		= ah_input,
	.output		= ah_output
};

static struct xfrm4_protocol ah4_protocol = {
	.handler	=	xfrm4_rcv,
	.input_handler	=	xfrm_input,
	.cb_handler	=	ah4_rcv_cb,
	.err_handler	=	ah4_err,
	.priority	=	0,
};

static int __init ah4_init(void)
{
	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
		pr_info("%s: can't add xfrm type\n", __func__);
		return -EAGAIN;
	}
	if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
		pr_info("%s: can't add protocol\n", __func__);
		xfrm_unregister_type(&ah_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ah4_fini(void)
{
	if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
		pr_info("%s: can't remove protocol\n", __func__);
	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
		pr_info("%s: can't remove xfrm type\n", __func__);
}

module_init(ah4_init);
module_exit(ah4_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
Commit	Line	Data
afd46503 JP	1	#define pr_fmt(fmt) "IPsec: " fmt
afd46503 JP	2
67df58a3	3	#include <crypto/algapi.h>
dff3bb06	4	#include <crypto/hash.h>
07d4ee58	5	#include <linux/err.h>
1da177e4	6	#include <linux/module.h>
5a0e3ad6	7	#include <linux/slab.h>
1da177e4 LT	8	#include <net/ip.h>
	9	#include <net/xfrm.h>
	10	#include <net/ah.h>
	11	#include <linux/crypto.h>
	12	#include <linux/pfkeyv2.h>
dff3bb06	13	#include <linux/scatterlist.h>
1da177e4	14	#include <net/icmp.h>
14c85021	15	#include <net/protocol.h>
1da177e4	16
dff3bb06 SK	17	struct ah_skb_cb {
	18	struct xfrm_skb_cb xfrm;
	19	void *tmp;
	20	};
	21
	22	#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
	23
	24	static void ah_alloc_tmp(struct crypto_ahash ahash, int nfrags,
	25	unsigned int size)
	26	{
	27	unsigned int len;
	28
	29	len = size + crypto_ahash_digestsize(ahash) +
	30	(crypto_ahash_alignmask(ahash) &
	31	~(crypto_tfm_ctx_alignment() - 1));
	32
	33	len = ALIGN(len, crypto_tfm_ctx_alignment());
	34
	35	len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
	36	len = ALIGN(len, __alignof__(struct scatterlist));
	37
	38	len += sizeof(struct scatterlist) * nfrags;
	39
	40	return kmalloc(len, GFP_ATOMIC);
	41	}
	42
	43	static inline u8 ah_tmp_auth(void tmp, unsigned int offset)
	44	{
	45	return tmp + offset;
	46	}
	47
	48	static inline u8 ah_tmp_icv(struct crypto_ahash ahash, void *tmp,
	49	unsigned int offset)
	50	{
	51	return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
	52	}
	53
	54	static inline struct ahash_request ah_tmp_req(struct crypto_ahash ahash,
	55	u8 *icv)
	56	{
	57	struct ahash_request *req;
	58
	59	req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
	60	crypto_tfm_ctx_alignment());
	61
	62	ahash_request_set_tfm(req, ahash);
	63
	64	return req;
	65	}
	66
	67	static inline struct scatterlist ah_req_sg(struct crypto_ahash ahash,
	68	struct ahash_request *req)
	69	{
	70	return (void *)ALIGN((unsigned long)(req + 1) +
	71	crypto_ahash_reqsize(ahash),
	72	__alignof__(struct scatterlist));
	73	}
1da177e4 LT	74
	75	/* Clear mutable options and find final destination to substitute
	76	* into IP header for icv calculation. Options are already checked
	77	* for validity, so paranoia is not required. */
	78
b71d1d42	79	static int ip_clear_mutable_options(const struct iphdr iph, __be32 daddr)
1da177e4	80	{
5e73ea1a	81	unsigned char optptr = (unsigned char )(iph+1);
1da177e4 LT	82	int l = iph->ihl*4 - sizeof(struct iphdr);
	83	int optlen;
	84
	85	while (l > 0) {
	86	switch (*optptr) {
	87	case IPOPT_END:
	88	return 0;
	89	case IPOPT_NOOP:
	90	l--;
	91	optptr++;
	92	continue;
	93	}
	94	optlen = optptr[1];
	95	if (optlen<2 \|\| optlen>l)
	96	return -EINVAL;
	97	switch (*optptr) {
	98	case IPOPT_SEC:
	99	case 0x85: /* Some "Extended Security" crap. */
11a03f78	100	case IPOPT_CIPSO:
1da177e4 LT	101	case IPOPT_RA:
	102	case 0x80\|21: /* RFC1770 */
	103	break;
	104	case IPOPT_LSRR:
	105	case IPOPT_SSRR:
	106	if (optlen < 6)
	107	return -EINVAL;
	108	memcpy(daddr, optptr+optlen-4, 4);
	109	/* Fall through */
	110	default:
96fe1c02	111	memset(optptr, 0, optlen);
1da177e4 LT	112	}
	113	l -= optlen;
	114	optptr += optlen;
	115	}
	116	return 0;
	117	}
	118
dff3bb06 SK	119	static void ah_output_done(struct crypto_async_request *base, int err)
	120	{
	121	u8 *icv;
	122	struct iphdr *iph;
	123	struct sk_buff *skb = base->data;
	124	struct xfrm_state *x = skb_dst(skb)->xfrm;
	125	struct ah_data *ahp = x->data;
	126	struct iphdr *top_iph = ip_hdr(skb);
	127	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	128	int ihl = ip_hdrlen(skb);
	129
	130	iph = AH_SKB_CB(skb)->tmp;
	131	icv = ah_tmp_icv(ahp->ahash, iph, ihl);
	132	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
	133
	134	top_iph->tos = iph->tos;
	135	top_iph->ttl = iph->ttl;
	136	top_iph->frag_off = iph->frag_off;
	137	if (top_iph->ihl != 5) {
	138	top_iph->daddr = iph->daddr;
	139	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	140	}
	141
dff3bb06 SK	142	kfree(AH_SKB_CB(skb)->tmp);
	143	xfrm_output_resume(skb, err);
	144	}
	145
1da177e4 LT	146	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	147	{
	148	int err;
dff3bb06 SK	149	int nfrags;
	150	int ihl;
	151	u8 *icv;
	152	struct sk_buff *trailer;
	153	struct crypto_ahash *ahash;
	154	struct ahash_request *req;
	155	struct scatterlist *sg;
1da177e4 LT	156	struct iphdr iph, top_iph;
	157	struct ip_auth_hdr *ah;
	158	struct ah_data *ahp;
d4d573d0 FD	159	int seqhi_len = 0;
	160	__be32 *seqhi;
	161	int sglists = 0;
	162	struct scatterlist *seqhisg;
dff3bb06 SK	163
	164	ahp = x->data;
	165	ahash = ahp->ahash;
	166
	167	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	168	goto out;
	169	nfrags = err;
1da177e4	170
7b277b1a	171	skb_push(skb, -skb_network_offset(skb));
dff3bb06 SK	172	ah = ip_auth_hdr(skb);
	173	ihl = ip_hdrlen(skb);
	174
d4d573d0 FD	175	if (x->props.flags & XFRM_STATE_ESN) {
	176	sglists = 1;
	177	seqhi_len = sizeof(*seqhi);
	178	}
dff3bb06	179	err = -ENOMEM;
d4d573d0	180	iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
dff3bb06 SK	181	if (!iph)
dff3bb06 SK	182	goto out;
d4d573d0 FD	183	seqhi = (__be32 )((char )iph + ihl);
d4d573d0 FD	184	icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
dff3bb06 SK	185	req = ah_tmp_req(ahash, icv);
dff3bb06 SK	186	sg = ah_req_sg(ahash, req);
d4d573d0	187	seqhisg = sg + nfrags;
dff3bb06 SK	188
	189	memset(ah->auth_data, 0, ahp->icv_trunc_len);
	190
eddc9ec5	191	top_iph = ip_hdr(skb);
1da177e4 LT	192
	193	iph->tos = top_iph->tos;
	194	iph->ttl = top_iph->ttl;
	195	iph->frag_off = top_iph->frag_off;
	196
	197	if (top_iph->ihl != 5) {
	198	iph->daddr = top_iph->daddr;
	199	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	200	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	201	if (err)
dff3bb06	202	goto out_free;
1da177e4 LT	203	}
1da177e4 LT	204
37fedd3a HX	205	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	206	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	207
	208	top_iph->tos = 0;
	209	top_iph->tot_len = htons(skb->len);
	210	top_iph->frag_off = 0;
	211	top_iph->ttl = 0;
1da177e4 LT	212	top_iph->check = 0;
1da177e4 LT	213
fa9921e4 ND	214	if (x->props.flags & XFRM_STATE_ALIGN4)
	215	ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
	216	else
	217	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	218
	219	ah->reserved = 0;
	220	ah->spi = x->id.spi;
1ce3644a	221	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
b7c6538c	222
d4d573d0	223	sg_init_table(sg, nfrags + sglists);
3f297707 JD	224	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	225	if (unlikely(err < 0))
	226	goto out_free;
b7c6538c	227
d4d573d0 FD	228	if (x->props.flags & XFRM_STATE_ESN) {
	229	/* Attach seqhi sg right after packet payload */
	230	*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
	231	sg_set_buf(seqhisg, seqhi, seqhi_len);
	232	}
	233	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
dff3bb06 SK	234	ahash_request_set_callback(req, 0, ah_output_done, skb);
	235
	236	AH_SKB_CB(skb)->tmp = iph;
	237
	238	err = crypto_ahash_digest(req);
	239	if (err) {
	240	if (err == -EINPROGRESS)
	241	goto out;
	242
068c2e70	243	if (err == -ENOSPC)
dff3bb06 SK	244	err = NET_XMIT_DROP;
	245	goto out_free;
	246	}
	247
	248	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
1da177e4 LT	249
	250	top_iph->tos = iph->tos;
	251	top_iph->ttl = iph->ttl;
	252	top_iph->frag_off = iph->frag_off;
	253	if (top_iph->ihl != 5) {
	254	top_iph->daddr = iph->daddr;
	255	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	256	}
	257
dff3bb06 SK	258	out_free:
	259	kfree(iph);
	260	out:
1da177e4 LT	261	return err;
	262	}
	263
dff3bb06 SK	264	static void ah_input_done(struct crypto_async_request *base, int err)
	265	{
	266	u8 *auth_data;
	267	u8 *icv;
	268	struct iphdr *work_iph;
	269	struct sk_buff *skb = base->data;
	270	struct xfrm_state *x = xfrm_input_state(skb);
	271	struct ah_data *ahp = x->data;
	272	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	273	int ihl = ip_hdrlen(skb);
	274	int ah_hlen = (ah->hdrlen + 2) << 2;
	275
ebd89a2d GBY	276	if (err)
	277	goto out;
	278
dff3bb06 SK	279	work_iph = AH_SKB_CB(skb)->tmp;
	280	auth_data = ah_tmp_auth(work_iph, ihl);
	281	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
	282
67df58a3	283	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
dff3bb06 SK	284	if (err)
	285	goto out;
	286
b7ea81a5 NB	287	err = ah->nexthdr;
b7ea81a5 NB	288
dff3bb06 SK	289	skb->network_header += ah_hlen;
	290	memcpy(skb_network_header(skb), work_iph, ihl);
	291	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	292
	293	if (x->props.mode == XFRM_MODE_TUNNEL)
	294	skb_reset_transport_header(skb);
	295	else
	296	skb_set_transport_header(skb, -ihl);
dff3bb06 SK	297	out:
	298	kfree(AH_SKB_CB(skb)->tmp);
	299	xfrm_input_resume(skb, err);
	300	}
	301
e695633e	302	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	303	{
1da177e4 LT	304	int ah_hlen;
31a4ab93	305	int ihl;
631a6698	306	int nexthdr;
dff3bb06 SK	307	int nfrags;
	308	u8 *auth_data;
	309	u8 *icv;
	310	struct sk_buff *trailer;
	311	struct crypto_ahash *ahash;
	312	struct ahash_request *req;
	313	struct scatterlist *sg;
	314	struct iphdr iph, work_iph;
1da177e4 LT	315	struct ip_auth_hdr *ah;
1da177e4 LT	316	struct ah_data *ahp;
dff3bb06	317	int err = -ENOMEM;
d8b2a860 FD	318	int seqhi_len = 0;
	319	__be32 *seqhi;
	320	int sglists = 0;
	321	struct scatterlist *seqhisg;
1da177e4	322
87bdc48d	323	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	324	goto out;
1da177e4 LT	325
87bdc48d	326	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	327	ahp = x->data;
dff3bb06 SK	328	ahash = ahp->ahash;
dff3bb06 SK	329
631a6698	330	nexthdr = ah->nexthdr;
1da177e4	331	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	332
fa9921e4 ND	333	if (x->props.flags & XFRM_STATE_ALIGN4) {
	334	if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
	335	ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
	336	goto out;
	337	} else {
	338	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	339	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
	340	goto out;
	341	}
1da177e4 LT	342
	343	if (!pskb_may_pull(skb, ah_hlen))
	344	goto out;
	345
	346	/* We are going to _remove_ AH header to keep sockets happy,
	347	* so... Later this can change. */
14bbd6a5	348	if (skb_unclone(skb, GFP_ATOMIC))
1da177e4 LT	349	goto out;
	350
	351	skb->ip_summed = CHECKSUM_NONE;
	352
dff3bb06 SK	353
	354	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	355	goto out;
	356	nfrags = err;
	357
4b0ef1f2 DH	358	ah = (struct ip_auth_hdr *)skb->data;
	359	iph = ip_hdr(skb);
	360	ihl = ip_hdrlen(skb);
	361
d8b2a860 FD	362	if (x->props.flags & XFRM_STATE_ESN) {
	363	sglists = 1;
	364	seqhi_len = sizeof(*seqhi);
	365	}
	366
	367	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
	368	ahp->icv_trunc_len + seqhi_len);
94c10f0e DM	369	if (!work_iph) {
94c10f0e DM	370	err = -ENOMEM;
dff3bb06	371	goto out;
94c10f0e	372	}
dff3bb06	373
d8b2a860 FD	374	seqhi = (__be32 )((char )work_iph + ihl);
d8b2a860 FD	375	auth_data = ah_tmp_auth(seqhi, seqhi_len);
dff3bb06 SK	376	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	377	req = ah_tmp_req(ahash, icv);
	378	sg = ah_req_sg(ahash, req);
d8b2a860	379	seqhisg = sg + nfrags;
1da177e4	380
dff3bb06 SK	381	memcpy(work_iph, iph, ihl);
	382	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	383	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	384
	385	iph->ttl = 0;
	386	iph->tos = 0;
	387	iph->frag_off = 0;
	388	iph->check = 0;
31a4ab93	389	if (ihl > sizeof(*iph)) {
d5a0a1e3	390	__be32 dummy;
dff3bb06 SK	391	err = ip_clear_mutable_options(iph, &dummy);
	392	if (err)
	393	goto out_free;
1da177e4	394	}
0ebea8ef	395
dff3bb06	396	skb_push(skb, ihl);
e905a9ed	397
d8b2a860	398	sg_init_table(sg, nfrags + sglists);
3f297707 JD	399	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	400	if (unlikely(err < 0))
	401	goto out_free;
dff3bb06	402
d8b2a860 FD	403	if (x->props.flags & XFRM_STATE_ESN) {
	404	/* Attach seqhi sg right after packet payload */
	405	*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
	406	sg_set_buf(seqhisg, seqhi, seqhi_len);
	407	}
	408	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
dff3bb06 SK	409	ahash_request_set_callback(req, 0, ah_input_done, skb);
	410
	411	AH_SKB_CB(skb)->tmp = work_iph;
	412
	413	err = crypto_ahash_digest(req);
	414	if (err) {
	415	if (err == -EINPROGRESS)
	416	goto out;
	417
dff3bb06	418	goto out_free;
1da177e4	419	}
0ebea8ef	420
67df58a3	421	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
0ebea8ef	422	if (err)
dff3bb06	423	goto out_free;
0ebea8ef	424
b0e380b1	425	skb->network_header += ah_hlen;
dff3bb06	426	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	427	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	428	if (x->props.mode == XFRM_MODE_TUNNEL)
	429	skb_reset_transport_header(skb);
	430	else
	431	skb_set_transport_header(skb, -ihl);
1da177e4	432
dff3bb06	433	err = nexthdr;
1da177e4	434
dff3bb06 SK	435	out_free:
dff3bb06 SK	436	kfree (work_iph);
1da177e4	437	out:
07d4ee58	438	return err;
1da177e4 LT	439	}
1da177e4 LT	440
e5b56454	441	static int ah4_err(struct sk_buff *skb, u32 info)
1da177e4	442	{
4fb236ba	443	struct net *net = dev_net(skb->dev);
b71d1d42	444	const struct iphdr iph = (const struct iphdr )skb->data;
d9319100	445	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	446	struct xfrm_state *x;
1da177e4 LT	447
55be7a9c DM	448	switch (icmp_hdr(skb)->type) {
	449	case ICMP_DEST_UNREACH:
	450	if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
e5b56454	451	return 0;
55be7a9c DM	452	case ICMP_REDIRECT:
	453	break;
	454	default:
e5b56454	455	return 0;
55be7a9c	456	}
1da177e4	457
b71d1d42 ED	458	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
b71d1d42 ED	459	ah->spi, IPPROTO_AH, AF_INET);
1da177e4	460	if (!x)
e5b56454	461	return 0;
55be7a9c	462
387aa65a	463	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
55be7a9c	464	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
387aa65a	465	else
55be7a9c	466	ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
1da177e4	467	xfrm_state_put(x);
e5b56454 SK	468
e5b56454 SK	469	return 0;
1da177e4 LT	470	}
1da177e4 LT	471
72cb6962	472	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	473	{
	474	struct ah_data *ahp = NULL;
	475	struct xfrm_algo_desc *aalg_desc;
dff3bb06	476	struct crypto_ahash *ahash;
1da177e4 LT	477
	478	if (!x->aalg)
	479	goto error;
	480
1da177e4 LT	481	if (x->encap)
	482	goto error;
	483
0da974f4	484	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	485	if (!ahp)
1da177e4 LT	486	return -ENOMEM;
1da177e4 LT	487
dff3bb06 SK	488	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
dff3bb06 SK	489	if (IS_ERR(ahash))
07d4ee58 HX	490	goto error;
07d4ee58 HX	491
dff3bb06 SK	492	ahp->ahash = ahash;
	493	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
	494	(x->aalg->alg_key_len + 7) / 8))
1da177e4	495	goto error;
e905a9ed	496
1da177e4 LT	497	/*
	498	* Lookup the algorithm description maintained by xfrm_algo,
	499	* verify crypto transform properties, and store information
	500	* we need for AH processing. This lookup cannot fail here
dff3bb06	501	* after a successful crypto_alloc_ahash().
1da177e4 LT	502	*/
	503	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	504	BUG_ON(!aalg_desc);
	505
	506	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	507	crypto_ahash_digestsize(ahash)) {
afd46503 JP	508	pr_info("%s: %s digestsize %u != %hu\n",
	509	__func__, x->aalg->alg_name,
	510	crypto_ahash_digestsize(ahash),
	511	aalg_desc->uinfo.auth.icv_fullbits / 8);
1da177e4 LT	512	goto error;
1da177e4 LT	513	}
e905a9ed	514
1da177e4	515	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	516	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	517
fa9921e4 ND	518	if (x->props.flags & XFRM_STATE_ALIGN4)
	519	x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
	520	ahp->icv_trunc_len);
	521	else
	522	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
	523	ahp->icv_trunc_len);
7e49e6de	524	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	525	x->props.header_len += sizeof(struct iphdr);
	526	x->data = ahp;
	527
	528	return 0;
	529
	530	error:
	531	if (ahp) {
dff3bb06	532	crypto_free_ahash(ahp->ahash);
1da177e4 LT	533	kfree(ahp);
	534	}
	535	return -EINVAL;
	536	}
	537
	538	static void ah_destroy(struct xfrm_state *x)
	539	{
	540	struct ah_data *ahp = x->data;
	541
	542	if (!ahp)
	543	return;
	544
dff3bb06	545	crypto_free_ahash(ahp->ahash);
1da177e4 LT	546	kfree(ahp);
	547	}
	548
e5b56454 SK	549	static int ah4_rcv_cb(struct sk_buff *skb, int err)
	550	{
	551	return 0;
	552	}
1da177e4	553
533cb5b0	554	static const struct xfrm_type ah_type =
1da177e4 LT	555	{
	556	.description = "AH4",
	557	.owner = THIS_MODULE,
	558	.proto = IPPROTO_AH,
436a0a40	559	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	560	.init_state = ah_init_state,
	561	.destructor = ah_destroy,
	562	.input = ah_input,
	563	.output = ah_output
	564	};
	565
e5b56454	566	static struct xfrm4_protocol ah4_protocol = {
1da177e4	567	.handler = xfrm4_rcv,
e5b56454 SK	568	.input_handler = xfrm_input,
e5b56454 SK	569	.cb_handler = ah4_rcv_cb,
1da177e4	570	.err_handler = ah4_err,
e5b56454	571	.priority = 0,
1da177e4 LT	572	};
	573
	574	static int __init ah4_init(void)
	575	{
	576	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
058bd4d2	577	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	578	return -EAGAIN;
1da177e4 LT	579	}
e5b56454	580	if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
058bd4d2	581	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	582	xfrm_unregister_type(&ah_type, AF_INET);
	583	return -EAGAIN;
	584	}
	585	return 0;
	586	}
	587
	588	static void __exit ah4_fini(void)
	589	{
e5b56454	590	if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
058bd4d2	591	pr_info("%s: can't remove protocol\n", __func__);
1da177e4	592	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
058bd4d2	593	pr_info("%s: can't remove xfrm type\n", __func__);
1da177e4 LT	594	}
	595
	596	module_init(ah4_init);
	597	module_exit(ah4_fini);
	598	MODULE_LICENSE("GPL");
d3d6dd3a	599	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);