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

#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;

	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);

	err = -ENOMEM;
	iph = ah_alloc_tmp(ahash, nfrags, ihl);
	if (!iph)
		goto out;

	icv = ah_tmp_icv(ahash, iph, ihl);
	req = ah_tmp_req(ahash, icv);
	sg = ah_req_sg(ahash, req);

	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);
	skb_to_sgvec(skb, sg, 0, skb->len);

	ahash_request_set_crypt(req, sg, icv, skb->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;

	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);
	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;

	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_cloned(skb) &&
	    pskb_expand_head(skb, 0, 0, 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);

	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
	if (!work_iph)
		goto out;

	auth_data = ah_tmp_auth(work_iph, ihl);
	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	req = ah_tmp_req(ahash, icv);
	sg = ah_req_sg(ahash, req);

	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);
	skb_to_sgvec(skb, sg, 0, skb->len);

	ahash_request_set_crypt(req, sg, icv, skb->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);
	skb_set_transport_header(skb, -ihl);

	err = nexthdr;

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

static void 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;

	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
	    icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
		return;

	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
			      ah->spi, IPPROTO_AH, AF_INET);
	if (!x)
		return;
	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	       ntohl(ah->spi), ntohl(iph->daddr));
	xfrm_state_put(x);
}

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)) {
		printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
		       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;

	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);

	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 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 const struct net_protocol ah4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	ah4_err,
	.no_policy	=	1,
	.netns_ok	=	1,
};

static int __init ah4_init(void)
{
	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
		printk(KERN_INFO "ip ah init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
		printk(KERN_INFO "ip ah init: can't add protocol\n");
		xfrm_unregister_type(&ah_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ah4_fini(void)
{
	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
		printk(KERN_INFO "ip ah close: can't remove protocol\n");
	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
		printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
}

module_init(ah4_init);
module_exit(ah4_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
Commit	Line	Data
dff3bb06	1	#include <crypto/hash.h>
07d4ee58	2	#include <linux/err.h>
1da177e4	3	#include <linux/module.h>
5a0e3ad6	4	#include <linux/slab.h>
1da177e4 LT	5	#include <net/ip.h>
	6	#include <net/xfrm.h>
	7	#include <net/ah.h>
	8	#include <linux/crypto.h>
	9	#include <linux/pfkeyv2.h>
dff3bb06	10	#include <linux/scatterlist.h>
1da177e4	11	#include <net/icmp.h>
14c85021	12	#include <net/protocol.h>
1da177e4	13
dff3bb06 SK	14	struct ah_skb_cb {
	15	struct xfrm_skb_cb xfrm;
	16	void *tmp;
	17	};
	18
	19	#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
	20
	21	static void ah_alloc_tmp(struct crypto_ahash ahash, int nfrags,
	22	unsigned int size)
	23	{
	24	unsigned int len;
	25
	26	len = size + crypto_ahash_digestsize(ahash) +
	27	(crypto_ahash_alignmask(ahash) &
	28	~(crypto_tfm_ctx_alignment() - 1));
	29
	30	len = ALIGN(len, crypto_tfm_ctx_alignment());
	31
	32	len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
	33	len = ALIGN(len, __alignof__(struct scatterlist));
	34
	35	len += sizeof(struct scatterlist) * nfrags;
	36
	37	return kmalloc(len, GFP_ATOMIC);
	38	}
	39
	40	static inline u8 ah_tmp_auth(void tmp, unsigned int offset)
	41	{
	42	return tmp + offset;
	43	}
	44
	45	static inline u8 ah_tmp_icv(struct crypto_ahash ahash, void *tmp,
	46	unsigned int offset)
	47	{
	48	return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
	49	}
	50
	51	static inline struct ahash_request ah_tmp_req(struct crypto_ahash ahash,
	52	u8 *icv)
	53	{
	54	struct ahash_request *req;
	55
	56	req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
	57	crypto_tfm_ctx_alignment());
	58
	59	ahash_request_set_tfm(req, ahash);
	60
	61	return req;
	62	}
	63
	64	static inline struct scatterlist ah_req_sg(struct crypto_ahash ahash,
	65	struct ahash_request *req)
	66	{
	67	return (void *)ALIGN((unsigned long)(req + 1) +
	68	crypto_ahash_reqsize(ahash),
	69	__alignof__(struct scatterlist));
	70	}
1da177e4 LT	71
	72	/* Clear mutable options and find final destination to substitute
	73	* into IP header for icv calculation. Options are already checked
	74	* for validity, so paranoia is not required. */
	75
b71d1d42	76	static int ip_clear_mutable_options(const struct iphdr iph, __be32 daddr)
1da177e4 LT	77	{
	78	unsigned char * optptr = (unsigned char*)(iph+1);
	79	int l = iph->ihl*4 - sizeof(struct iphdr);
	80	int optlen;
	81
	82	while (l > 0) {
	83	switch (*optptr) {
	84	case IPOPT_END:
	85	return 0;
	86	case IPOPT_NOOP:
	87	l--;
	88	optptr++;
	89	continue;
	90	}
	91	optlen = optptr[1];
	92	if (optlen<2 \|\| optlen>l)
	93	return -EINVAL;
	94	switch (*optptr) {
	95	case IPOPT_SEC:
	96	case 0x85: /* Some "Extended Security" crap. */
11a03f78	97	case IPOPT_CIPSO:
1da177e4 LT	98	case IPOPT_RA:
	99	case 0x80\|21: /* RFC1770 */
	100	break;
	101	case IPOPT_LSRR:
	102	case IPOPT_SSRR:
	103	if (optlen < 6)
	104	return -EINVAL;
	105	memcpy(daddr, optptr+optlen-4, 4);
	106	/* Fall through */
	107	default:
96fe1c02	108	memset(optptr, 0, optlen);
1da177e4 LT	109	}
	110	l -= optlen;
	111	optptr += optlen;
	112	}
	113	return 0;
	114	}
	115
dff3bb06 SK	116	static void ah_output_done(struct crypto_async_request *base, int err)
	117	{
	118	u8 *icv;
	119	struct iphdr *iph;
	120	struct sk_buff *skb = base->data;
	121	struct xfrm_state *x = skb_dst(skb)->xfrm;
	122	struct ah_data *ahp = x->data;
	123	struct iphdr *top_iph = ip_hdr(skb);
	124	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	125	int ihl = ip_hdrlen(skb);
	126
	127	iph = AH_SKB_CB(skb)->tmp;
	128	icv = ah_tmp_icv(ahp->ahash, iph, ihl);
	129	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
	130
	131	top_iph->tos = iph->tos;
	132	top_iph->ttl = iph->ttl;
	133	top_iph->frag_off = iph->frag_off;
	134	if (top_iph->ihl != 5) {
	135	top_iph->daddr = iph->daddr;
	136	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	137	}
	138
dff3bb06 SK	139	kfree(AH_SKB_CB(skb)->tmp);
	140	xfrm_output_resume(skb, err);
	141	}
	142
1da177e4 LT	143	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	144	{
	145	int err;
dff3bb06 SK	146	int nfrags;
	147	int ihl;
	148	u8 *icv;
	149	struct sk_buff *trailer;
	150	struct crypto_ahash *ahash;
	151	struct ahash_request *req;
	152	struct scatterlist *sg;
1da177e4 LT	153	struct iphdr iph, top_iph;
	154	struct ip_auth_hdr *ah;
	155	struct ah_data *ahp;
dff3bb06 SK	156
	157	ahp = x->data;
	158	ahash = ahp->ahash;
	159
	160	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	161	goto out;
	162	nfrags = err;
1da177e4	163
7b277b1a	164	skb_push(skb, -skb_network_offset(skb));
dff3bb06 SK	165	ah = ip_auth_hdr(skb);
	166	ihl = ip_hdrlen(skb);
	167
	168	err = -ENOMEM;
	169	iph = ah_alloc_tmp(ahash, nfrags, ihl);
	170	if (!iph)
	171	goto out;
	172
	173	icv = ah_tmp_icv(ahash, iph, ihl);
	174	req = ah_tmp_req(ahash, icv);
	175	sg = ah_req_sg(ahash, req);
	176
	177	memset(ah->auth_data, 0, ahp->icv_trunc_len);
	178
eddc9ec5	179	top_iph = ip_hdr(skb);
1da177e4 LT	180
	181	iph->tos = top_iph->tos;
	182	iph->ttl = top_iph->ttl;
	183	iph->frag_off = top_iph->frag_off;
	184
	185	if (top_iph->ihl != 5) {
	186	iph->daddr = top_iph->daddr;
	187	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	188	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	189	if (err)
dff3bb06	190	goto out_free;
1da177e4 LT	191	}
1da177e4 LT	192
37fedd3a HX	193	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	194	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	195
	196	top_iph->tos = 0;
	197	top_iph->tot_len = htons(skb->len);
	198	top_iph->frag_off = 0;
	199	top_iph->ttl = 0;
1da177e4 LT	200	top_iph->check = 0;
1da177e4 LT	201
fa9921e4 ND	202	if (x->props.flags & XFRM_STATE_ALIGN4)
	203	ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
	204	else
	205	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	206
	207	ah->reserved = 0;
	208	ah->spi = x->id.spi;
1ce3644a	209	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
b7c6538c	210
dff3bb06 SK	211	sg_init_table(sg, nfrags);
dff3bb06 SK	212	skb_to_sgvec(skb, sg, 0, skb->len);
b7c6538c	213
dff3bb06 SK	214	ahash_request_set_crypt(req, sg, icv, skb->len);
	215	ahash_request_set_callback(req, 0, ah_output_done, skb);
	216
	217	AH_SKB_CB(skb)->tmp = iph;
	218
	219	err = crypto_ahash_digest(req);
	220	if (err) {
	221	if (err == -EINPROGRESS)
	222	goto out;
	223
	224	if (err == -EBUSY)
	225	err = NET_XMIT_DROP;
	226	goto out_free;
	227	}
	228
	229	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
1da177e4 LT	230
	231	top_iph->tos = iph->tos;
	232	top_iph->ttl = iph->ttl;
	233	top_iph->frag_off = iph->frag_off;
	234	if (top_iph->ihl != 5) {
	235	top_iph->daddr = iph->daddr;
	236	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	237	}
	238
dff3bb06 SK	239	out_free:
	240	kfree(iph);
	241	out:
1da177e4 LT	242	return err;
	243	}
	244
dff3bb06 SK	245	static void ah_input_done(struct crypto_async_request *base, int err)
	246	{
	247	u8 *auth_data;
	248	u8 *icv;
	249	struct iphdr *work_iph;
	250	struct sk_buff *skb = base->data;
	251	struct xfrm_state *x = xfrm_input_state(skb);
	252	struct ah_data *ahp = x->data;
	253	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	254	int ihl = ip_hdrlen(skb);
	255	int ah_hlen = (ah->hdrlen + 2) << 2;
	256
	257	work_iph = AH_SKB_CB(skb)->tmp;
	258	auth_data = ah_tmp_auth(work_iph, ihl);
	259	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
	260
	261	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
	262	if (err)
	263	goto out;
	264
b7ea81a5 NB	265	err = ah->nexthdr;
b7ea81a5 NB	266
dff3bb06 SK	267	skb->network_header += ah_hlen;
	268	memcpy(skb_network_header(skb), work_iph, ihl);
	269	__skb_pull(skb, ah_hlen + ihl);
	270	skb_set_transport_header(skb, -ihl);
dff3bb06 SK	271	out:
	272	kfree(AH_SKB_CB(skb)->tmp);
	273	xfrm_input_resume(skb, err);
	274	}
	275
e695633e	276	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	277	{
1da177e4 LT	278	int ah_hlen;
31a4ab93	279	int ihl;
631a6698	280	int nexthdr;
dff3bb06 SK	281	int nfrags;
	282	u8 *auth_data;
	283	u8 *icv;
	284	struct sk_buff *trailer;
	285	struct crypto_ahash *ahash;
	286	struct ahash_request *req;
	287	struct scatterlist *sg;
	288	struct iphdr iph, work_iph;
1da177e4 LT	289	struct ip_auth_hdr *ah;
1da177e4 LT	290	struct ah_data *ahp;
dff3bb06	291	int err = -ENOMEM;
1da177e4	292
87bdc48d	293	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	294	goto out;
1da177e4 LT	295
87bdc48d	296	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	297	ahp = x->data;
dff3bb06 SK	298	ahash = ahp->ahash;
dff3bb06 SK	299
631a6698	300	nexthdr = ah->nexthdr;
1da177e4	301	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	302
fa9921e4 ND	303	if (x->props.flags & XFRM_STATE_ALIGN4) {
	304	if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
	305	ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
	306	goto out;
	307	} else {
	308	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	309	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
	310	goto out;
	311	}
1da177e4 LT	312
	313	if (!pskb_may_pull(skb, ah_hlen))
	314	goto out;
	315
	316	/* We are going to _remove_ AH header to keep sockets happy,
	317	* so... Later this can change. */
	318	if (skb_cloned(skb) &&
	319	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	320	goto out;
	321
	322	skb->ip_summed = CHECKSUM_NONE;
	323
dff3bb06 SK	324
	325	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	326	goto out;
	327	nfrags = err;
	328
4b0ef1f2 DH	329	ah = (struct ip_auth_hdr *)skb->data;
	330	iph = ip_hdr(skb);
	331	ihl = ip_hdrlen(skb);
	332
dff3bb06 SK	333	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
	334	if (!work_iph)
	335	goto out;
	336
	337	auth_data = ah_tmp_auth(work_iph, ihl);
	338	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	339	req = ah_tmp_req(ahash, icv);
	340	sg = ah_req_sg(ahash, req);
1da177e4	341
dff3bb06 SK	342	memcpy(work_iph, iph, ihl);
	343	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	344	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	345
	346	iph->ttl = 0;
	347	iph->tos = 0;
	348	iph->frag_off = 0;
	349	iph->check = 0;
31a4ab93	350	if (ihl > sizeof(*iph)) {
d5a0a1e3	351	__be32 dummy;
dff3bb06 SK	352	err = ip_clear_mutable_options(iph, &dummy);
	353	if (err)
	354	goto out_free;
1da177e4	355	}
0ebea8ef	356
dff3bb06	357	skb_push(skb, ihl);
e905a9ed	358
dff3bb06 SK	359	sg_init_table(sg, nfrags);
	360	skb_to_sgvec(skb, sg, 0, skb->len);
	361
	362	ahash_request_set_crypt(req, sg, icv, skb->len);
	363	ahash_request_set_callback(req, 0, ah_input_done, skb);
	364
	365	AH_SKB_CB(skb)->tmp = work_iph;
	366
	367	err = crypto_ahash_digest(req);
	368	if (err) {
	369	if (err == -EINPROGRESS)
	370	goto out;
	371
dff3bb06	372	goto out_free;
1da177e4	373	}
0ebea8ef	374
dff3bb06	375	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
0ebea8ef	376	if (err)
dff3bb06	377	goto out_free;
0ebea8ef	378
b0e380b1	379	skb->network_header += ah_hlen;
dff3bb06	380	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	381	__skb_pull(skb, ah_hlen + ihl);
dff3bb06	382	skb_set_transport_header(skb, -ihl);
1da177e4	383
dff3bb06	384	err = nexthdr;
1da177e4	385
dff3bb06 SK	386	out_free:
dff3bb06 SK	387	kfree (work_iph);
1da177e4	388	out:
07d4ee58	389	return err;
1da177e4 LT	390	}
	391
	392	static void ah4_err(struct sk_buff *skb, u32 info)
	393	{
4fb236ba	394	struct net *net = dev_net(skb->dev);
b71d1d42	395	const struct iphdr iph = (const struct iphdr )skb->data;
d9319100	396	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	397	struct xfrm_state *x;
1da177e4 LT	398
88c7664f ACM	399	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	400	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	401	return;
1da177e4 LT	402
b71d1d42 ED	403	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
b71d1d42 ED	404	ah->spi, IPPROTO_AH, AF_INET);
1da177e4 LT	405	if (!x)
	406	return;
	407	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	408	ntohl(ah->spi), ntohl(iph->daddr));
	409	xfrm_state_put(x);
	410	}
	411
72cb6962	412	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	413	{
	414	struct ah_data *ahp = NULL;
	415	struct xfrm_algo_desc *aalg_desc;
dff3bb06	416	struct crypto_ahash *ahash;
1da177e4 LT	417
	418	if (!x->aalg)
	419	goto error;
	420
1da177e4 LT	421	if (x->encap)
	422	goto error;
	423
0da974f4	424	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	425	if (!ahp)
1da177e4 LT	426	return -ENOMEM;
1da177e4 LT	427
dff3bb06 SK	428	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
dff3bb06 SK	429	if (IS_ERR(ahash))
07d4ee58 HX	430	goto error;
07d4ee58 HX	431
dff3bb06 SK	432	ahp->ahash = ahash;
	433	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
	434	(x->aalg->alg_key_len + 7) / 8))
1da177e4	435	goto error;
e905a9ed	436
1da177e4 LT	437	/*
	438	* Lookup the algorithm description maintained by xfrm_algo,
	439	* verify crypto transform properties, and store information
	440	* we need for AH processing. This lookup cannot fail here
dff3bb06	441	* after a successful crypto_alloc_ahash().
1da177e4 LT	442	*/
	443	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	444	BUG_ON(!aalg_desc);
	445
	446	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	447	crypto_ahash_digestsize(ahash)) {
1da177e4	448	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
dff3bb06	449	x->aalg->alg_name, crypto_ahash_digestsize(ahash),
1da177e4 LT	450	aalg_desc->uinfo.auth.icv_fullbits/8);
	451	goto error;
	452	}
e905a9ed	453
1da177e4	454	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	455	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	456
1da177e4	457	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
e905a9ed	458
fa9921e4 ND	459	if (x->props.flags & XFRM_STATE_ALIGN4)
	460	x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
	461	ahp->icv_trunc_len);
	462	else
	463	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
	464	ahp->icv_trunc_len);
7e49e6de	465	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	466	x->props.header_len += sizeof(struct iphdr);
	467	x->data = ahp;
	468
	469	return 0;
	470
	471	error:
	472	if (ahp) {
dff3bb06	473	crypto_free_ahash(ahp->ahash);
1da177e4 LT	474	kfree(ahp);
	475	}
	476	return -EINVAL;
	477	}
	478
	479	static void ah_destroy(struct xfrm_state *x)
	480	{
	481	struct ah_data *ahp = x->data;
	482
	483	if (!ahp)
	484	return;
	485
dff3bb06	486	crypto_free_ahash(ahp->ahash);
1da177e4 LT	487	kfree(ahp);
	488	}
	489
	490
533cb5b0	491	static const struct xfrm_type ah_type =
1da177e4 LT	492	{
	493	.description = "AH4",
	494	.owner = THIS_MODULE,
	495	.proto = IPPROTO_AH,
436a0a40	496	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	497	.init_state = ah_init_state,
	498	.destructor = ah_destroy,
	499	.input = ah_input,
	500	.output = ah_output
	501	};
	502
32613090	503	static const struct net_protocol ah4_protocol = {
1da177e4 LT	504	.handler = xfrm4_rcv,
	505	.err_handler = ah4_err,
	506	.no_policy = 1,
4fb236ba	507	.netns_ok = 1,
1da177e4 LT	508	};
	509
	510	static int __init ah4_init(void)
	511	{
	512	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
	513	printk(KERN_INFO "ip ah init: can't add xfrm type\n");
	514	return -EAGAIN;
	515	}
	516	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
	517	printk(KERN_INFO "ip ah init: can't add protocol\n");
	518	xfrm_unregister_type(&ah_type, AF_INET);
	519	return -EAGAIN;
	520	}
	521	return 0;
	522	}
	523
	524	static void __exit ah4_fini(void)
	525	{
	526	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
	527	printk(KERN_INFO "ip ah close: can't remove protocol\n");
	528	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
	529	printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
	530	}
	531
	532	module_init(ah4_init);
	533	module_exit(ah4_fini);
	534	MODULE_LICENSE("GPL");
d3d6dd3a	535	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);