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

#include <crypto/hash.h>
#include <linux/err.h>
#include <linux/module.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(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));
	}

	err = ah->nexthdr;

	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;

	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);

	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;

	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 = ah->nexthdr;
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 (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;

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

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

	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;

		if (err == -EBUSY)
			err = NET_XMIT_DROP;
		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);
	struct iphdr *iph = (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, (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);

	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 LT	3	#include <linux/module.h>
	4	#include <net/ip.h>
	5	#include <net/xfrm.h>
	6	#include <net/ah.h>
	7	#include <linux/crypto.h>
	8	#include <linux/pfkeyv2.h>
dff3bb06	9	#include <linux/scatterlist.h>
1da177e4	10	#include <net/icmp.h>
14c85021	11	#include <net/protocol.h>
1da177e4	12
dff3bb06 SK	13	struct ah_skb_cb {
	14	struct xfrm_skb_cb xfrm;
	15	void *tmp;
	16	};
	17
	18	#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
	19
	20	static void ah_alloc_tmp(struct crypto_ahash ahash, int nfrags,
	21	unsigned int size)
	22	{
	23	unsigned int len;
	24
	25	len = size + crypto_ahash_digestsize(ahash) +
	26	(crypto_ahash_alignmask(ahash) &
	27	~(crypto_tfm_ctx_alignment() - 1));
	28
	29	len = ALIGN(len, crypto_tfm_ctx_alignment());
	30
	31	len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
	32	len = ALIGN(len, __alignof__(struct scatterlist));
	33
	34	len += sizeof(struct scatterlist) * nfrags;
	35
	36	return kmalloc(len, GFP_ATOMIC);
	37	}
	38
	39	static inline u8 ah_tmp_auth(void tmp, unsigned int offset)
	40	{
	41	return tmp + offset;
	42	}
	43
	44	static inline u8 ah_tmp_icv(struct crypto_ahash ahash, void *tmp,
	45	unsigned int offset)
	46	{
	47	return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
	48	}
	49
	50	static inline struct ahash_request ah_tmp_req(struct crypto_ahash ahash,
	51	u8 *icv)
	52	{
	53	struct ahash_request *req;
	54
	55	req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
	56	crypto_tfm_ctx_alignment());
	57
	58	ahash_request_set_tfm(req, ahash);
	59
	60	return req;
	61	}
	62
	63	static inline struct scatterlist ah_req_sg(struct crypto_ahash ahash,
	64	struct ahash_request *req)
	65	{
	66	return (void *)ALIGN((unsigned long)(req + 1) +
	67	crypto_ahash_reqsize(ahash),
	68	__alignof__(struct scatterlist));
	69	}
1da177e4 LT	70
	71	/* Clear mutable options and find final destination to substitute
	72	* into IP header for icv calculation. Options are already checked
	73	* for validity, so paranoia is not required. */
	74
d5a0a1e3	75	static int ip_clear_mutable_options(struct iphdr iph, __be32 daddr)
1da177e4 LT	76	{
	77	unsigned char * optptr = (unsigned char*)(iph+1);
	78	int l = iph->ihl*4 - sizeof(struct iphdr);
	79	int optlen;
	80
	81	while (l > 0) {
	82	switch (*optptr) {
	83	case IPOPT_END:
	84	return 0;
	85	case IPOPT_NOOP:
	86	l--;
	87	optptr++;
	88	continue;
	89	}
	90	optlen = optptr[1];
	91	if (optlen<2 \|\| optlen>l)
	92	return -EINVAL;
	93	switch (*optptr) {
	94	case IPOPT_SEC:
	95	case 0x85: /* Some "Extended Security" crap. */
11a03f78	96	case IPOPT_CIPSO:
1da177e4 LT	97	case IPOPT_RA:
	98	case 0x80\|21: /* RFC1770 */
	99	break;
	100	case IPOPT_LSRR:
	101	case IPOPT_SSRR:
	102	if (optlen < 6)
	103	return -EINVAL;
	104	memcpy(daddr, optptr+optlen-4, 4);
	105	/* Fall through */
	106	default:
96fe1c02	107	memset(optptr, 0, optlen);
1da177e4 LT	108	}
	109	l -= optlen;
	110	optptr += optlen;
	111	}
	112	return 0;
	113	}
	114
dff3bb06 SK	115	static void ah_output_done(struct crypto_async_request *base, int err)
	116	{
	117	u8 *icv;
	118	struct iphdr *iph;
	119	struct sk_buff *skb = base->data;
	120	struct xfrm_state *x = skb_dst(skb)->xfrm;
	121	struct ah_data *ahp = x->data;
	122	struct iphdr *top_iph = ip_hdr(skb);
	123	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	124	int ihl = ip_hdrlen(skb);
	125
	126	iph = AH_SKB_CB(skb)->tmp;
	127	icv = ah_tmp_icv(ahp->ahash, iph, ihl);
	128	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
	129
	130	top_iph->tos = iph->tos;
	131	top_iph->ttl = iph->ttl;
	132	top_iph->frag_off = iph->frag_off;
	133	if (top_iph->ihl != 5) {
	134	top_iph->daddr = iph->daddr;
	135	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	136	}
	137
	138	err = ah->nexthdr;
	139
	140	kfree(AH_SKB_CB(skb)->tmp);
	141	xfrm_output_resume(skb, err);
	142	}
	143
1da177e4 LT	144	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	145	{
	146	int err;
dff3bb06 SK	147	int nfrags;
	148	int ihl;
	149	u8 *icv;
	150	struct sk_buff *trailer;
	151	struct crypto_ahash *ahash;
	152	struct ahash_request *req;
	153	struct scatterlist *sg;
1da177e4 LT	154	struct iphdr iph, top_iph;
	155	struct ip_auth_hdr *ah;
	156	struct ah_data *ahp;
dff3bb06 SK	157
	158	ahp = x->data;
	159	ahash = ahp->ahash;
	160
	161	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	162	goto out;
	163	nfrags = err;
1da177e4	164
7b277b1a	165	skb_push(skb, -skb_network_offset(skb));
dff3bb06 SK	166	ah = ip_auth_hdr(skb);
	167	ihl = ip_hdrlen(skb);
	168
	169	err = -ENOMEM;
	170	iph = ah_alloc_tmp(ahash, nfrags, ihl);
	171	if (!iph)
	172	goto out;
	173
	174	icv = ah_tmp_icv(ahash, iph, ihl);
	175	req = ah_tmp_req(ahash, icv);
	176	sg = ah_req_sg(ahash, req);
	177
	178	memset(ah->auth_data, 0, ahp->icv_trunc_len);
	179
eddc9ec5	180	top_iph = ip_hdr(skb);
1da177e4 LT	181
	182	iph->tos = top_iph->tos;
	183	iph->ttl = top_iph->ttl;
	184	iph->frag_off = top_iph->frag_off;
	185
	186	if (top_iph->ihl != 5) {
	187	iph->daddr = top_iph->daddr;
	188	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	189	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	190	if (err)
dff3bb06	191	goto out_free;
1da177e4 LT	192	}
1da177e4 LT	193
37fedd3a HX	194	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	195	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	196
	197	top_iph->tos = 0;
	198	top_iph->tot_len = htons(skb->len);
	199	top_iph->frag_off = 0;
	200	top_iph->ttl = 0;
1da177e4 LT	201	top_iph->check = 0;
1da177e4 LT	202
87bdc48d	203	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	204
	205	ah->reserved = 0;
	206	ah->spi = x->id.spi;
b318e0e4	207	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
b7c6538c	208
dff3bb06 SK	209	sg_init_table(sg, nfrags);
dff3bb06 SK	210	skb_to_sgvec(skb, sg, 0, skb->len);
b7c6538c	211
dff3bb06 SK	212	ahash_request_set_crypt(req, sg, icv, skb->len);
	213	ahash_request_set_callback(req, 0, ah_output_done, skb);
	214
	215	AH_SKB_CB(skb)->tmp = iph;
	216
	217	err = crypto_ahash_digest(req);
	218	if (err) {
	219	if (err == -EINPROGRESS)
	220	goto out;
	221
	222	if (err == -EBUSY)
	223	err = NET_XMIT_DROP;
	224	goto out_free;
	225	}
	226
	227	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
1da177e4 LT	228
	229	top_iph->tos = iph->tos;
	230	top_iph->ttl = iph->ttl;
	231	top_iph->frag_off = iph->frag_off;
	232	if (top_iph->ihl != 5) {
	233	top_iph->daddr = iph->daddr;
	234	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	235	}
	236
dff3bb06 SK	237	out_free:
	238	kfree(iph);
	239	out:
1da177e4 LT	240	return err;
	241	}
	242
dff3bb06 SK	243	static void ah_input_done(struct crypto_async_request *base, int err)
	244	{
	245	u8 *auth_data;
	246	u8 *icv;
	247	struct iphdr *work_iph;
	248	struct sk_buff *skb = base->data;
	249	struct xfrm_state *x = xfrm_input_state(skb);
	250	struct ah_data *ahp = x->data;
	251	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	252	int ihl = ip_hdrlen(skb);
	253	int ah_hlen = (ah->hdrlen + 2) << 2;
	254
	255	work_iph = AH_SKB_CB(skb)->tmp;
	256	auth_data = ah_tmp_auth(work_iph, ihl);
	257	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
	258
	259	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
	260	if (err)
	261	goto out;
	262
	263	skb->network_header += ah_hlen;
	264	memcpy(skb_network_header(skb), work_iph, ihl);
	265	__skb_pull(skb, ah_hlen + ihl);
	266	skb_set_transport_header(skb, -ihl);
	267
	268	err = ah->nexthdr;
	269	out:
	270	kfree(AH_SKB_CB(skb)->tmp);
	271	xfrm_input_resume(skb, err);
	272	}
	273
e695633e	274	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	275	{
1da177e4 LT	276	int ah_hlen;
31a4ab93	277	int ihl;
631a6698	278	int nexthdr;
dff3bb06 SK	279	int nfrags;
	280	u8 *auth_data;
	281	u8 *icv;
	282	struct sk_buff *trailer;
	283	struct crypto_ahash *ahash;
	284	struct ahash_request *req;
	285	struct scatterlist *sg;
	286	struct iphdr iph, work_iph;
1da177e4 LT	287	struct ip_auth_hdr *ah;
1da177e4 LT	288	struct ah_data *ahp;
dff3bb06	289	int err = -ENOMEM;
1da177e4	290
87bdc48d	291	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	292	goto out;
1da177e4 LT	293
87bdc48d	294	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	295	ahp = x->data;
dff3bb06 SK	296	ahash = ahp->ahash;
dff3bb06 SK	297
631a6698	298	nexthdr = ah->nexthdr;
1da177e4	299	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	300
87bdc48d HX	301	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
87bdc48d HX	302	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
1da177e4 LT	303	goto out;
	304
	305	if (!pskb_may_pull(skb, ah_hlen))
	306	goto out;
	307
	308	/* We are going to _remove_ AH header to keep sockets happy,
	309	* so... Later this can change. */
	310	if (skb_cloned(skb) &&
	311	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	312	goto out;
	313
	314	skb->ip_summed = CHECKSUM_NONE;
	315
87bdc48d	316	ah = (struct ip_auth_hdr *)skb->data;
eddc9ec5	317	iph = ip_hdr(skb);
dff3bb06 SK	318	ihl = ip_hdrlen(skb);
	319
	320	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	321	goto out;
	322	nfrags = err;
	323
	324	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
	325	if (!work_iph)
	326	goto out;
	327
	328	auth_data = ah_tmp_auth(work_iph, ihl);
	329	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	330	req = ah_tmp_req(ahash, icv);
	331	sg = ah_req_sg(ahash, req);
1da177e4	332
dff3bb06 SK	333	memcpy(work_iph, iph, ihl);
	334	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	335	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	336
	337	iph->ttl = 0;
	338	iph->tos = 0;
	339	iph->frag_off = 0;
	340	iph->check = 0;
31a4ab93	341	if (ihl > sizeof(*iph)) {
d5a0a1e3	342	__be32 dummy;
dff3bb06 SK	343	err = ip_clear_mutable_options(iph, &dummy);
	344	if (err)
	345	goto out_free;
1da177e4	346	}
0ebea8ef	347
dff3bb06	348	skb_push(skb, ihl);
e905a9ed	349
dff3bb06 SK	350	sg_init_table(sg, nfrags);
	351	skb_to_sgvec(skb, sg, 0, skb->len);
	352
	353	ahash_request_set_crypt(req, sg, icv, skb->len);
	354	ahash_request_set_callback(req, 0, ah_input_done, skb);
	355
	356	AH_SKB_CB(skb)->tmp = work_iph;
	357
	358	err = crypto_ahash_digest(req);
	359	if (err) {
	360	if (err == -EINPROGRESS)
	361	goto out;
	362
	363	if (err == -EBUSY)
	364	err = NET_XMIT_DROP;
	365	goto out_free;
1da177e4	366	}
0ebea8ef	367
dff3bb06	368	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
0ebea8ef	369	if (err)
dff3bb06	370	goto out_free;
0ebea8ef	371
b0e380b1	372	skb->network_header += ah_hlen;
dff3bb06	373	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	374	__skb_pull(skb, ah_hlen + ihl);
dff3bb06	375	skb_set_transport_header(skb, -ihl);
1da177e4	376
dff3bb06	377	err = nexthdr;
1da177e4	378
dff3bb06 SK	379	out_free:
dff3bb06 SK	380	kfree (work_iph);
1da177e4	381	out:
07d4ee58	382	return err;
1da177e4 LT	383	}
	384
	385	static void ah4_err(struct sk_buff *skb, u32 info)
	386	{
4fb236ba	387	struct net *net = dev_net(skb->dev);
d9319100 JK	388	struct iphdr iph = (struct iphdr )skb->data;
d9319100 JK	389	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	390	struct xfrm_state *x;
1da177e4 LT	391
88c7664f ACM	392	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	393	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	394	return;
1da177e4 LT	395
4fb236ba	396	x = xfrm_state_lookup(net, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
1da177e4 LT	397	if (!x)
	398	return;
	399	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	400	ntohl(ah->spi), ntohl(iph->daddr));
	401	xfrm_state_put(x);
	402	}
	403
72cb6962	404	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	405	{
	406	struct ah_data *ahp = NULL;
	407	struct xfrm_algo_desc *aalg_desc;
dff3bb06	408	struct crypto_ahash *ahash;
1da177e4 LT	409
	410	if (!x->aalg)
	411	goto error;
	412
1da177e4 LT	413	if (x->encap)
	414	goto error;
	415
0da974f4	416	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	417	if (!ahp)
1da177e4 LT	418	return -ENOMEM;
1da177e4 LT	419
dff3bb06 SK	420	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
dff3bb06 SK	421	if (IS_ERR(ahash))
07d4ee58 HX	422	goto error;
07d4ee58 HX	423
dff3bb06 SK	424	ahp->ahash = ahash;
	425	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
	426	(x->aalg->alg_key_len + 7) / 8))
1da177e4	427	goto error;
e905a9ed	428
1da177e4 LT	429	/*
	430	* Lookup the algorithm description maintained by xfrm_algo,
	431	* verify crypto transform properties, and store information
	432	* we need for AH processing. This lookup cannot fail here
dff3bb06	433	* after a successful crypto_alloc_ahash().
1da177e4 LT	434	*/
	435	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	436	BUG_ON(!aalg_desc);
	437
	438	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	439	crypto_ahash_digestsize(ahash)) {
1da177e4	440	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
dff3bb06	441	x->aalg->alg_name, crypto_ahash_digestsize(ahash),
1da177e4 LT	442	aalg_desc->uinfo.auth.icv_fullbits/8);
	443	goto error;
	444	}
e905a9ed	445
1da177e4	446	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	447	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	448
1da177e4	449	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
e905a9ed	450
87bdc48d HX	451	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
87bdc48d HX	452	ahp->icv_trunc_len);
7e49e6de	453	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	454	x->props.header_len += sizeof(struct iphdr);
	455	x->data = ahp;
	456
	457	return 0;
	458
	459	error:
	460	if (ahp) {
dff3bb06	461	crypto_free_ahash(ahp->ahash);
1da177e4 LT	462	kfree(ahp);
	463	}
	464	return -EINVAL;
	465	}
	466
	467	static void ah_destroy(struct xfrm_state *x)
	468	{
	469	struct ah_data *ahp = x->data;
	470
	471	if (!ahp)
	472	return;
	473
dff3bb06	474	crypto_free_ahash(ahp->ahash);
1da177e4 LT	475	kfree(ahp);
	476	}
	477
	478
533cb5b0	479	static const struct xfrm_type ah_type =
1da177e4 LT	480	{
	481	.description = "AH4",
	482	.owner = THIS_MODULE,
	483	.proto = IPPROTO_AH,
436a0a40	484	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	485	.init_state = ah_init_state,
	486	.destructor = ah_destroy,
	487	.input = ah_input,
	488	.output = ah_output
	489	};
	490
32613090	491	static const struct net_protocol ah4_protocol = {
1da177e4 LT	492	.handler = xfrm4_rcv,
	493	.err_handler = ah4_err,
	494	.no_policy = 1,
4fb236ba	495	.netns_ok = 1,
1da177e4 LT	496	};
	497
	498	static int __init ah4_init(void)
	499	{
	500	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
	501	printk(KERN_INFO "ip ah init: can't add xfrm type\n");
	502	return -EAGAIN;
	503	}
	504	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
	505	printk(KERN_INFO "ip ah init: can't add protocol\n");
	506	xfrm_unregister_type(&ah_type, AF_INET);
	507	return -EAGAIN;
	508	}
	509	return 0;
	510	}
	511
	512	static void __exit ah4_fini(void)
	513	{
	514	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
	515	printk(KERN_INFO "ip ah close: can't remove protocol\n");
	516	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
	517	printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
	518	}
	519
	520	module_init(ah4_init);
	521	module_exit(ah4_fini);
	522	MODULE_LICENSE("GPL");
d3d6dd3a	523	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);