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

#define pr_fmt(fmt) "IPsec: " fmt

#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);
	skb_to_sgvec_nomark(skb, sg, 0, skb->len);

	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 == -EBUSY)
			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 = memcmp(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);
	skb_to_sgvec_nomark(skb, sg, 0, skb->len);

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