[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;

	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);

	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;

	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);
	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 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;

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

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

	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
		atomic_inc(&flow_cache_genid);
		rt_genid_bump(net);

		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);
}

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;

	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) {
		pr_info("%s: can't add xfrm type\n", __func__);
		return -EAGAIN;
	}
	if (inet_add_protocol(&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 (inet_del_protocol(&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;
dff3bb06 SK	158
	159	ahp = x->data;
	160	ahash = ahp->ahash;
	161
	162	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	163	goto out;
	164	nfrags = err;
1da177e4	165
7b277b1a	166	skb_push(skb, -skb_network_offset(skb));
dff3bb06 SK	167	ah = ip_auth_hdr(skb);
	168	ihl = ip_hdrlen(skb);
	169
	170	err = -ENOMEM;
	171	iph = ah_alloc_tmp(ahash, nfrags, ihl);
	172	if (!iph)
	173	goto out;
	174
	175	icv = ah_tmp_icv(ahash, iph, ihl);
	176	req = ah_tmp_req(ahash, icv);
	177	sg = ah_req_sg(ahash, req);
	178
	179	memset(ah->auth_data, 0, ahp->icv_trunc_len);
	180
eddc9ec5	181	top_iph = ip_hdr(skb);
1da177e4 LT	182
	183	iph->tos = top_iph->tos;
	184	iph->ttl = top_iph->ttl;
	185	iph->frag_off = top_iph->frag_off;
	186
	187	if (top_iph->ihl != 5) {
	188	iph->daddr = top_iph->daddr;
	189	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	190	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	191	if (err)
dff3bb06	192	goto out_free;
1da177e4 LT	193	}
1da177e4 LT	194
37fedd3a HX	195	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	196	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	197
	198	top_iph->tos = 0;
	199	top_iph->tot_len = htons(skb->len);
	200	top_iph->frag_off = 0;
	201	top_iph->ttl = 0;
1da177e4 LT	202	top_iph->check = 0;
1da177e4 LT	203
fa9921e4 ND	204	if (x->props.flags & XFRM_STATE_ALIGN4)
	205	ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
	206	else
	207	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	208
	209	ah->reserved = 0;
	210	ah->spi = x->id.spi;
1ce3644a	211	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
b7c6538c	212
dff3bb06 SK	213	sg_init_table(sg, nfrags);
dff3bb06 SK	214	skb_to_sgvec(skb, sg, 0, skb->len);
b7c6538c	215
dff3bb06 SK	216	ahash_request_set_crypt(req, sg, icv, skb->len);
	217	ahash_request_set_callback(req, 0, ah_output_done, skb);
	218
	219	AH_SKB_CB(skb)->tmp = iph;
	220
	221	err = crypto_ahash_digest(req);
	222	if (err) {
	223	if (err == -EINPROGRESS)
	224	goto out;
	225
	226	if (err == -EBUSY)
	227	err = NET_XMIT_DROP;
	228	goto out_free;
	229	}
	230
	231	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
1da177e4 LT	232
	233	top_iph->tos = iph->tos;
	234	top_iph->ttl = iph->ttl;
	235	top_iph->frag_off = iph->frag_off;
	236	if (top_iph->ihl != 5) {
	237	top_iph->daddr = iph->daddr;
	238	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	239	}
	240
dff3bb06 SK	241	out_free:
	242	kfree(iph);
	243	out:
1da177e4 LT	244	return err;
	245	}
	246
dff3bb06 SK	247	static void ah_input_done(struct crypto_async_request *base, int err)
	248	{
	249	u8 *auth_data;
	250	u8 *icv;
	251	struct iphdr *work_iph;
	252	struct sk_buff *skb = base->data;
	253	struct xfrm_state *x = xfrm_input_state(skb);
	254	struct ah_data *ahp = x->data;
	255	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	256	int ihl = ip_hdrlen(skb);
	257	int ah_hlen = (ah->hdrlen + 2) << 2;
	258
	259	work_iph = AH_SKB_CB(skb)->tmp;
	260	auth_data = ah_tmp_auth(work_iph, ihl);
	261	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
	262
	263	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
	264	if (err)
	265	goto out;
	266
b7ea81a5 NB	267	err = ah->nexthdr;
b7ea81a5 NB	268
dff3bb06 SK	269	skb->network_header += ah_hlen;
	270	memcpy(skb_network_header(skb), work_iph, ihl);
	271	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	272
	273	if (x->props.mode == XFRM_MODE_TUNNEL)
	274	skb_reset_transport_header(skb);
	275	else
	276	skb_set_transport_header(skb, -ihl);
dff3bb06 SK	277	out:
	278	kfree(AH_SKB_CB(skb)->tmp);
	279	xfrm_input_resume(skb, err);
	280	}
	281
e695633e	282	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	283	{
1da177e4 LT	284	int ah_hlen;
31a4ab93	285	int ihl;
631a6698	286	int nexthdr;
dff3bb06 SK	287	int nfrags;
	288	u8 *auth_data;
	289	u8 *icv;
	290	struct sk_buff *trailer;
	291	struct crypto_ahash *ahash;
	292	struct ahash_request *req;
	293	struct scatterlist *sg;
	294	struct iphdr iph, work_iph;
1da177e4 LT	295	struct ip_auth_hdr *ah;
1da177e4 LT	296	struct ah_data *ahp;
dff3bb06	297	int err = -ENOMEM;
1da177e4	298
87bdc48d	299	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	300	goto out;
1da177e4 LT	301
87bdc48d	302	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	303	ahp = x->data;
dff3bb06 SK	304	ahash = ahp->ahash;
dff3bb06 SK	305
631a6698	306	nexthdr = ah->nexthdr;
1da177e4	307	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	308
fa9921e4 ND	309	if (x->props.flags & XFRM_STATE_ALIGN4) {
	310	if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
	311	ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
	312	goto out;
	313	} else {
	314	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	315	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
	316	goto out;
	317	}
1da177e4 LT	318
	319	if (!pskb_may_pull(skb, ah_hlen))
	320	goto out;
	321
	322	/* We are going to _remove_ AH header to keep sockets happy,
	323	* so... Later this can change. */
	324	if (skb_cloned(skb) &&
	325	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	326	goto out;
	327
	328	skb->ip_summed = CHECKSUM_NONE;
	329
dff3bb06 SK	330
	331	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	332	goto out;
	333	nfrags = err;
	334
4b0ef1f2 DH	335	ah = (struct ip_auth_hdr *)skb->data;
	336	iph = ip_hdr(skb);
	337	ihl = ip_hdrlen(skb);
	338
dff3bb06 SK	339	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
	340	if (!work_iph)
	341	goto out;
	342
	343	auth_data = ah_tmp_auth(work_iph, ihl);
	344	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	345	req = ah_tmp_req(ahash, icv);
	346	sg = ah_req_sg(ahash, req);
1da177e4	347
dff3bb06 SK	348	memcpy(work_iph, iph, ihl);
	349	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	350	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	351
	352	iph->ttl = 0;
	353	iph->tos = 0;
	354	iph->frag_off = 0;
	355	iph->check = 0;
31a4ab93	356	if (ihl > sizeof(*iph)) {
d5a0a1e3	357	__be32 dummy;
dff3bb06 SK	358	err = ip_clear_mutable_options(iph, &dummy);
	359	if (err)
	360	goto out_free;
1da177e4	361	}
0ebea8ef	362
dff3bb06	363	skb_push(skb, ihl);
e905a9ed	364
dff3bb06 SK	365	sg_init_table(sg, nfrags);
	366	skb_to_sgvec(skb, sg, 0, skb->len);
	367
	368	ahash_request_set_crypt(req, sg, icv, skb->len);
	369	ahash_request_set_callback(req, 0, ah_input_done, skb);
	370
	371	AH_SKB_CB(skb)->tmp = work_iph;
	372
	373	err = crypto_ahash_digest(req);
	374	if (err) {
	375	if (err == -EINPROGRESS)
	376	goto out;
	377
dff3bb06	378	goto out_free;
1da177e4	379	}
0ebea8ef	380
dff3bb06	381	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
0ebea8ef	382	if (err)
dff3bb06	383	goto out_free;
0ebea8ef	384
b0e380b1	385	skb->network_header += ah_hlen;
dff3bb06	386	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	387	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	388	if (x->props.mode == XFRM_MODE_TUNNEL)
	389	skb_reset_transport_header(skb);
	390	else
	391	skb_set_transport_header(skb, -ihl);
1da177e4	392
dff3bb06	393	err = nexthdr;
1da177e4	394
dff3bb06 SK	395	out_free:
dff3bb06 SK	396	kfree (work_iph);
1da177e4	397	out:
07d4ee58	398	return err;
1da177e4 LT	399	}
	400
	401	static void ah4_err(struct sk_buff *skb, u32 info)
	402	{
4fb236ba	403	struct net *net = dev_net(skb->dev);
b71d1d42	404	const struct iphdr iph = (const struct iphdr )skb->data;
d9319100	405	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	406	struct xfrm_state *x;
1da177e4 LT	407
55be7a9c DM	408	switch (icmp_hdr(skb)->type) {
	409	case ICMP_DEST_UNREACH:
	410	if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
	411	return;
	412	case ICMP_REDIRECT:
	413	break;
	414	default:
1da177e4	415	return;
55be7a9c	416	}
1da177e4	417
b71d1d42 ED	418	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
b71d1d42 ED	419	ah->spi, IPPROTO_AH, AF_INET);
1da177e4 LT	420	if (!x)
1da177e4 LT	421	return;
55be7a9c	422
05ab86c5 SK	423	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
	424	atomic_inc(&flow_cache_genid);
	425	rt_genid_bump(net);
	426
55be7a9c	427	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
05ab86c5	428	} else
55be7a9c	429	ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
1da177e4 LT	430	xfrm_state_put(x);
	431	}
	432
72cb6962	433	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	434	{
	435	struct ah_data *ahp = NULL;
	436	struct xfrm_algo_desc *aalg_desc;
dff3bb06	437	struct crypto_ahash *ahash;
1da177e4 LT	438
	439	if (!x->aalg)
	440	goto error;
	441
1da177e4 LT	442	if (x->encap)
	443	goto error;
	444
0da974f4	445	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	446	if (!ahp)
1da177e4 LT	447	return -ENOMEM;
1da177e4 LT	448
dff3bb06 SK	449	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
dff3bb06 SK	450	if (IS_ERR(ahash))
07d4ee58 HX	451	goto error;
07d4ee58 HX	452
dff3bb06 SK	453	ahp->ahash = ahash;
	454	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
	455	(x->aalg->alg_key_len + 7) / 8))
1da177e4	456	goto error;
e905a9ed	457
1da177e4 LT	458	/*
	459	* Lookup the algorithm description maintained by xfrm_algo,
	460	* verify crypto transform properties, and store information
	461	* we need for AH processing. This lookup cannot fail here
dff3bb06	462	* after a successful crypto_alloc_ahash().
1da177e4 LT	463	*/
	464	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	465	BUG_ON(!aalg_desc);
	466
	467	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	468	crypto_ahash_digestsize(ahash)) {
afd46503 JP	469	pr_info("%s: %s digestsize %u != %hu\n",
	470	__func__, x->aalg->alg_name,
	471	crypto_ahash_digestsize(ahash),
	472	aalg_desc->uinfo.auth.icv_fullbits / 8);
1da177e4 LT	473	goto error;
1da177e4 LT	474	}
e905a9ed	475
1da177e4	476	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	477	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	478
1da177e4	479	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
e905a9ed	480
fa9921e4 ND	481	if (x->props.flags & XFRM_STATE_ALIGN4)
	482	x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
	483	ahp->icv_trunc_len);
	484	else
	485	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
	486	ahp->icv_trunc_len);
7e49e6de	487	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	488	x->props.header_len += sizeof(struct iphdr);
	489	x->data = ahp;
	490
	491	return 0;
	492
	493	error:
	494	if (ahp) {
dff3bb06	495	crypto_free_ahash(ahp->ahash);
1da177e4 LT	496	kfree(ahp);
	497	}
	498	return -EINVAL;
	499	}
	500
	501	static void ah_destroy(struct xfrm_state *x)
	502	{
	503	struct ah_data *ahp = x->data;
	504
	505	if (!ahp)
	506	return;
	507
dff3bb06	508	crypto_free_ahash(ahp->ahash);
1da177e4 LT	509	kfree(ahp);
	510	}
	511
	512
533cb5b0	513	static const struct xfrm_type ah_type =
1da177e4 LT	514	{
	515	.description = "AH4",
	516	.owner = THIS_MODULE,
	517	.proto = IPPROTO_AH,
436a0a40	518	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	519	.init_state = ah_init_state,
	520	.destructor = ah_destroy,
	521	.input = ah_input,
	522	.output = ah_output
	523	};
	524
32613090	525	static const struct net_protocol ah4_protocol = {
1da177e4 LT	526	.handler = xfrm4_rcv,
	527	.err_handler = ah4_err,
	528	.no_policy = 1,
4fb236ba	529	.netns_ok = 1,
1da177e4 LT	530	};
	531
	532	static int __init ah4_init(void)
	533	{
	534	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
058bd4d2	535	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	536	return -EAGAIN;
	537	}
	538	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
058bd4d2	539	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	540	xfrm_unregister_type(&ah_type, AF_INET);
	541	return -EAGAIN;
	542	}
	543	return 0;
	544	}
	545
	546	static void __exit ah4_fini(void)
	547	{
	548	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
058bd4d2	549	pr_info("%s: can't remove protocol\n", __func__);
1da177e4	550	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
058bd4d2	551	pr_info("%s: can't remove xfrm type\n", __func__);
1da177e4 LT	552	}
	553
	554	module_init(ah4_init);
	555	module_exit(ah4_fini);
	556	MODULE_LICENSE("GPL");
d3d6dd3a	557	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);