[mirror_ubuntu-bionic-kernel.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;

	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_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);

	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)
		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;
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
	273	work_iph = AH_SKB_CB(skb)->tmp;
	274	auth_data = ah_tmp_auth(work_iph, ihl);
	275	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
	276
	277	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
	278	if (err)
	279	goto out;
	280
b7ea81a5 NB	281	err = ah->nexthdr;
b7ea81a5 NB	282
dff3bb06 SK	283	skb->network_header += ah_hlen;
	284	memcpy(skb_network_header(skb), work_iph, ihl);
	285	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	286
	287	if (x->props.mode == XFRM_MODE_TUNNEL)
	288	skb_reset_transport_header(skb);
	289	else
	290	skb_set_transport_header(skb, -ihl);
dff3bb06 SK	291	out:
	292	kfree(AH_SKB_CB(skb)->tmp);
	293	xfrm_input_resume(skb, err);
	294	}
	295
e695633e	296	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	297	{
1da177e4 LT	298	int ah_hlen;
31a4ab93	299	int ihl;
631a6698	300	int nexthdr;
dff3bb06 SK	301	int nfrags;
	302	u8 *auth_data;
	303	u8 *icv;
	304	struct sk_buff *trailer;
	305	struct crypto_ahash *ahash;
	306	struct ahash_request *req;
	307	struct scatterlist *sg;
	308	struct iphdr iph, work_iph;
1da177e4 LT	309	struct ip_auth_hdr *ah;
1da177e4 LT	310	struct ah_data *ahp;
dff3bb06	311	int err = -ENOMEM;
1da177e4	312
87bdc48d	313	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	314	goto out;
1da177e4 LT	315
87bdc48d	316	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	317	ahp = x->data;
dff3bb06 SK	318	ahash = ahp->ahash;
dff3bb06 SK	319
631a6698	320	nexthdr = ah->nexthdr;
1da177e4	321	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	322
fa9921e4 ND	323	if (x->props.flags & XFRM_STATE_ALIGN4) {
	324	if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
	325	ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
	326	goto out;
	327	} else {
	328	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	329	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
	330	goto out;
	331	}
1da177e4 LT	332
	333	if (!pskb_may_pull(skb, ah_hlen))
	334	goto out;
	335
	336	/* We are going to _remove_ AH header to keep sockets happy,
	337	* so... Later this can change. */
14bbd6a5	338	if (skb_unclone(skb, GFP_ATOMIC))
1da177e4 LT	339	goto out;
	340
	341	skb->ip_summed = CHECKSUM_NONE;
	342
dff3bb06 SK	343
	344	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	345	goto out;
	346	nfrags = err;
	347
4b0ef1f2 DH	348	ah = (struct ip_auth_hdr *)skb->data;
	349	iph = ip_hdr(skb);
	350	ihl = ip_hdrlen(skb);
	351
dff3bb06 SK	352	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
	353	if (!work_iph)
	354	goto out;
	355
	356	auth_data = ah_tmp_auth(work_iph, ihl);
	357	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	358	req = ah_tmp_req(ahash, icv);
	359	sg = ah_req_sg(ahash, req);
1da177e4	360
dff3bb06 SK	361	memcpy(work_iph, iph, ihl);
	362	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	363	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	364
	365	iph->ttl = 0;
	366	iph->tos = 0;
	367	iph->frag_off = 0;
	368	iph->check = 0;
31a4ab93	369	if (ihl > sizeof(*iph)) {
d5a0a1e3	370	__be32 dummy;
dff3bb06 SK	371	err = ip_clear_mutable_options(iph, &dummy);
	372	if (err)
	373	goto out_free;
1da177e4	374	}
0ebea8ef	375
dff3bb06	376	skb_push(skb, ihl);
e905a9ed	377
dff3bb06 SK	378	sg_init_table(sg, nfrags);
	379	skb_to_sgvec(skb, sg, 0, skb->len);
	380
	381	ahash_request_set_crypt(req, sg, icv, skb->len);
	382	ahash_request_set_callback(req, 0, ah_input_done, skb);
	383
	384	AH_SKB_CB(skb)->tmp = work_iph;
	385
	386	err = crypto_ahash_digest(req);
	387	if (err) {
	388	if (err == -EINPROGRESS)
	389	goto out;
	390
dff3bb06	391	goto out_free;
1da177e4	392	}
0ebea8ef	393
dff3bb06	394	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
0ebea8ef	395	if (err)
dff3bb06	396	goto out_free;
0ebea8ef	397
b0e380b1	398	skb->network_header += ah_hlen;
dff3bb06	399	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	400	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	401	if (x->props.mode == XFRM_MODE_TUNNEL)
	402	skb_reset_transport_header(skb);
	403	else
	404	skb_set_transport_header(skb, -ihl);
1da177e4	405
dff3bb06	406	err = nexthdr;
1da177e4	407
dff3bb06 SK	408	out_free:
dff3bb06 SK	409	kfree (work_iph);
1da177e4	410	out:
07d4ee58	411	return err;
1da177e4 LT	412	}
	413
	414	static void ah4_err(struct sk_buff *skb, u32 info)
	415	{
4fb236ba	416	struct net *net = dev_net(skb->dev);
b71d1d42	417	const struct iphdr iph = (const struct iphdr )skb->data;
d9319100	418	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	419	struct xfrm_state *x;
1da177e4 LT	420
55be7a9c DM	421	switch (icmp_hdr(skb)->type) {
	422	case ICMP_DEST_UNREACH:
	423	if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
	424	return;
	425	case ICMP_REDIRECT:
	426	break;
	427	default:
1da177e4	428	return;
55be7a9c	429	}
1da177e4	430
b71d1d42 ED	431	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
b71d1d42 ED	432	ah->spi, IPPROTO_AH, AF_INET);
1da177e4 LT	433	if (!x)
1da177e4 LT	434	return;
55be7a9c	435
387aa65a	436	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
55be7a9c	437	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
387aa65a	438	else
55be7a9c	439	ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
1da177e4 LT	440	xfrm_state_put(x);
	441	}
	442
72cb6962	443	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	444	{
	445	struct ah_data *ahp = NULL;
	446	struct xfrm_algo_desc *aalg_desc;
dff3bb06	447	struct crypto_ahash *ahash;
1da177e4 LT	448
	449	if (!x->aalg)
	450	goto error;
	451
1da177e4 LT	452	if (x->encap)
	453	goto error;
	454
0da974f4	455	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	456	if (!ahp)
1da177e4 LT	457	return -ENOMEM;
1da177e4 LT	458
dff3bb06 SK	459	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
dff3bb06 SK	460	if (IS_ERR(ahash))
07d4ee58 HX	461	goto error;
07d4ee58 HX	462
dff3bb06 SK	463	ahp->ahash = ahash;
	464	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
	465	(x->aalg->alg_key_len + 7) / 8))
1da177e4	466	goto error;
e905a9ed	467
1da177e4 LT	468	/*
	469	* Lookup the algorithm description maintained by xfrm_algo,
	470	* verify crypto transform properties, and store information
	471	* we need for AH processing. This lookup cannot fail here
dff3bb06	472	* after a successful crypto_alloc_ahash().
1da177e4 LT	473	*/
	474	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	475	BUG_ON(!aalg_desc);
	476
	477	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	478	crypto_ahash_digestsize(ahash)) {
afd46503 JP	479	pr_info("%s: %s digestsize %u != %hu\n",
	480	__func__, x->aalg->alg_name,
	481	crypto_ahash_digestsize(ahash),
	482	aalg_desc->uinfo.auth.icv_fullbits / 8);
1da177e4 LT	483	goto error;
1da177e4 LT	484	}
e905a9ed	485
1da177e4	486	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	487	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	488
1da177e4	489	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
e905a9ed	490
fa9921e4 ND	491	if (x->props.flags & XFRM_STATE_ALIGN4)
	492	x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
	493	ahp->icv_trunc_len);
	494	else
	495	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
	496	ahp->icv_trunc_len);
7e49e6de	497	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	498	x->props.header_len += sizeof(struct iphdr);
	499	x->data = ahp;
	500
	501	return 0;
	502
	503	error:
	504	if (ahp) {
dff3bb06	505	crypto_free_ahash(ahp->ahash);
1da177e4 LT	506	kfree(ahp);
	507	}
	508	return -EINVAL;
	509	}
	510
	511	static void ah_destroy(struct xfrm_state *x)
	512	{
	513	struct ah_data *ahp = x->data;
	514
	515	if (!ahp)
	516	return;
	517
dff3bb06	518	crypto_free_ahash(ahp->ahash);
1da177e4 LT	519	kfree(ahp);
	520	}
	521
	522
533cb5b0	523	static const struct xfrm_type ah_type =
1da177e4 LT	524	{
	525	.description = "AH4",
	526	.owner = THIS_MODULE,
	527	.proto = IPPROTO_AH,
436a0a40	528	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	529	.init_state = ah_init_state,
	530	.destructor = ah_destroy,
	531	.input = ah_input,
	532	.output = ah_output
	533	};
	534
32613090	535	static const struct net_protocol ah4_protocol = {
1da177e4 LT	536	.handler = xfrm4_rcv,
	537	.err_handler = ah4_err,
	538	.no_policy = 1,
4fb236ba	539	.netns_ok = 1,
1da177e4 LT	540	};
	541
	542	static int __init ah4_init(void)
	543	{
	544	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
058bd4d2	545	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	546	return -EAGAIN;
	547	}
	548	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
058bd4d2	549	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	550	xfrm_unregister_type(&ah_type, AF_INET);
	551	return -EAGAIN;
	552	}
	553	return 0;
	554	}
	555
	556	static void __exit ah4_fini(void)
	557	{
	558	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
058bd4d2	559	pr_info("%s: can't remove protocol\n", __func__);
1da177e4	560	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
058bd4d2	561	pr_info("%s: can't remove xfrm type\n", __func__);
1da177e4 LT	562	}
	563
	564	module_init(ah4_init);
	565	module_exit(ah4_fini);
	566	MODULE_LICENSE("GPL");
d3d6dd3a	567	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);