[mirror_ubuntu-hirsute-kernel.git] / net / ipv4 / ah4.c

// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) "IPsec: " fmt

#include <crypto/algapi.h>
#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);
	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	if (unlikely(err < 0))
		goto out_free;

	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 == -ENOSPC)
			err = NET_XMIT_DROP;
		goto out_free;
	}

	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);

	top_iph->tos = iph->tos;
	top_iph->ttl = iph->ttl;
	top_iph->frag_off = iph->frag_off;
	if (top_iph->ihl != 5) {
		top_iph->daddr = iph->daddr;
		memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	}

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

static void ah_input_done(struct crypto_async_request *base, int err)
{
	u8 *auth_data;
	u8 *icv;
	struct iphdr *work_iph;
	struct sk_buff *skb = base->data;
	struct xfrm_state *x = xfrm_input_state(skb);
	struct ah_data *ahp = x->data;
	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	int ihl = ip_hdrlen(skb);
	int ah_hlen = (ah->hdrlen + 2) << 2;

	if (err)
		goto out;

	work_iph = AH_SKB_CB(skb)->tmp;
	auth_data = ah_tmp_auth(work_iph, ihl);
	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);

	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
	if (err)
		goto out;

	err = ah->nexthdr;

	skb->network_header += ah_hlen;
	memcpy(skb_network_header(skb), work_iph, ihl);
	__skb_pull(skb, ah_hlen + ihl);

	if (x->props.mode == XFRM_MODE_TUNNEL)
		skb_reset_transport_header(skb);
	else
		skb_set_transport_header(skb, -ihl);
out:
	kfree(AH_SKB_CB(skb)->tmp);
	xfrm_input_resume(skb, err);
}

static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int ah_hlen;
	int ihl;
	int nexthdr;
	int nfrags;
	u8 *auth_data;
	u8 *icv;
	struct sk_buff *trailer;
	struct crypto_ahash *ahash;
	struct ahash_request *req;
	struct scatterlist *sg;
	struct iphdr *iph, *work_iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	int err = -ENOMEM;
	int seqhi_len = 0;
	__be32 *seqhi;
	int sglists = 0;
	struct scatterlist *seqhisg;

	if (!pskb_may_pull(skb, sizeof(*ah)))
		goto out;

	ah = (struct ip_auth_hdr *)skb->data;
	ahp = x->data;
	ahash = ahp->ahash;

	nexthdr = ah->nexthdr;
	ah_hlen = (ah->hdrlen + 2) << 2;

	if (x->props.flags & XFRM_STATE_ALIGN4) {
		if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
		    ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
			goto out;
	} else {
		if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
		    ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
			goto out;
	}

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_unclone(skb, GFP_ATOMIC))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;


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

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

	if (x->props.flags & XFRM_STATE_ESN) {
		sglists = 1;
		seqhi_len = sizeof(*seqhi);
	}

	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
				ahp->icv_trunc_len + seqhi_len);
	if (!work_iph) {
		err = -ENOMEM;
		goto out;
	}

	seqhi = (__be32 *)((char *)work_iph + ihl);
	auth_data = ah_tmp_auth(seqhi, seqhi_len);
	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	req = ah_tmp_req(ahash, icv);
	sg = ah_req_sg(ahash, req);
	seqhisg = sg + nfrags;

	memcpy(work_iph, iph, ihl);
	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	memset(ah->auth_data, 0, ahp->icv_trunc_len);

	iph->ttl = 0;
	iph->tos = 0;
	iph->frag_off = 0;
	iph->check = 0;
	if (ihl > sizeof(*iph)) {
		__be32 dummy;
		err = ip_clear_mutable_options(iph, &dummy);
		if (err)
			goto out_free;
	}

	skb_push(skb, ihl);

	sg_init_table(sg, nfrags + sglists);
	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	if (unlikely(err < 0))
		goto out_free;

	if (x->props.flags & XFRM_STATE_ESN) {
		/* Attach seqhi sg right after packet payload */
		*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
		sg_set_buf(seqhisg, seqhi, seqhi_len);
	}
	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
	ahash_request_set_callback(req, 0, ah_input_done, skb);

	AH_SKB_CB(skb)->tmp = work_iph;

	err = crypto_ahash_digest(req);
	if (err) {
		if (err == -EINPROGRESS)
			goto out;

		goto out_free;
	}

	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
	if (err)
		goto out_free;

	skb->network_header += ah_hlen;
	memcpy(skb_network_header(skb), work_iph, ihl);
	__skb_pull(skb, ah_hlen + ihl);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		skb_reset_transport_header(skb);
	else
		skb_set_transport_header(skb, -ihl);

	err = nexthdr;

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

static int ah4_err(struct sk_buff *skb, u32 info)
{
	struct net *net = dev_net(skb->dev);
	const struct iphdr *iph = (const struct iphdr *)skb->data;
	struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	switch (icmp_hdr(skb)->type) {
	case ICMP_DEST_UNREACH:
		if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
			return 0;
	case ICMP_REDIRECT:
		break;
	default:
		return 0;
	}

	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
			      ah->spi, IPPROTO_AH, AF_INET);
	if (!x)
		return 0;

	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
		ipv4_update_pmtu(skb, net, info, 0, IPPROTO_AH);
	else
		ipv4_redirect(skb, net, 0, IPPROTO_AH);
	xfrm_state_put(x);

	return 0;
}

static int ah_init_state(struct xfrm_state *x)
{
	struct ah_data *ahp = NULL;
	struct xfrm_algo_desc *aalg_desc;
	struct crypto_ahash *ahash;

	if (!x->aalg)
		goto error;

	if (x->encap)
		goto error;

	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
	if (!ahp)
		return -ENOMEM;

	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
	if (IS_ERR(ahash))
		goto error;

	ahp->ahash = ahash;
	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
				(x->aalg->alg_key_len + 7) / 8))
		goto error;

	/*
	 * Lookup the algorithm description maintained by xfrm_algo,
	 * verify crypto transform properties, and store information
	 * we need for AH processing.  This lookup cannot fail here
	 * after a successful crypto_alloc_ahash().
	 */
	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	BUG_ON(!aalg_desc);

	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
	    crypto_ahash_digestsize(ahash)) {
		pr_info("%s: %s digestsize %u != %hu\n",
			__func__, x->aalg->alg_name,
			crypto_ahash_digestsize(ahash),
			aalg_desc->uinfo.auth.icv_fullbits / 8);
		goto error;
	}

	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;

	if (x->props.flags & XFRM_STATE_ALIGN4)
		x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
						  ahp->icv_trunc_len);
	else
		x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
						  ahp->icv_trunc_len);
	if (x->props.mode == XFRM_MODE_TUNNEL)
		x->props.header_len += sizeof(struct iphdr);
	x->data = ahp;

	return 0;

error:
	if (ahp) {
		crypto_free_ahash(ahp->ahash);
		kfree(ahp);
	}
	return -EINVAL;
}

static void ah_destroy(struct xfrm_state *x)
{
	struct ah_data *ahp = x->data;

	if (!ahp)
		return;

	crypto_free_ahash(ahp->ahash);
	kfree(ahp);
}

static int ah4_rcv_cb(struct sk_buff *skb, int err)
{
	return 0;
}

static const struct xfrm_type ah_type =
{
	.description	= "AH4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_AH,
	.flags		= XFRM_TYPE_REPLAY_PROT,
	.init_state	= ah_init_state,
	.destructor	= ah_destroy,
	.input		= ah_input,
	.output		= ah_output
};

static struct xfrm4_protocol ah4_protocol = {
	.handler	=	xfrm4_rcv,
	.input_handler	=	xfrm_input,
	.cb_handler	=	ah4_rcv_cb,
	.err_handler	=	ah4_err,
	.priority	=	0,
};

static int __init ah4_init(void)
{
	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
		pr_info("%s: can't add xfrm type\n", __func__);
		return -EAGAIN;
	}
	if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
		pr_info("%s: can't add protocol\n", __func__);
		xfrm_unregister_type(&ah_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ah4_fini(void)
{
	if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
		pr_info("%s: can't remove protocol\n", __func__);
	xfrm_unregister_type(&ah_type, AF_INET);
}

module_init(ah4_init);
module_exit(ah4_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
Commit	Line	Data
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
afd46503 JP	2	#define pr_fmt(fmt) "IPsec: " fmt
afd46503 JP	3
67df58a3	4	#include <crypto/algapi.h>
dff3bb06	5	#include <crypto/hash.h>
07d4ee58	6	#include <linux/err.h>
1da177e4	7	#include <linux/module.h>
5a0e3ad6	8	#include <linux/slab.h>
1da177e4 LT	9	#include <net/ip.h>
	10	#include <net/xfrm.h>
	11	#include <net/ah.h>
	12	#include <linux/crypto.h>
	13	#include <linux/pfkeyv2.h>
dff3bb06	14	#include <linux/scatterlist.h>
1da177e4	15	#include <net/icmp.h>
14c85021	16	#include <net/protocol.h>
1da177e4	17
dff3bb06 SK	18	struct ah_skb_cb {
	19	struct xfrm_skb_cb xfrm;
	20	void *tmp;
	21	};
	22
	23	#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
	24
	25	static void ah_alloc_tmp(struct crypto_ahash ahash, int nfrags,
	26	unsigned int size)
	27	{
	28	unsigned int len;
	29
	30	len = size + crypto_ahash_digestsize(ahash) +
	31	(crypto_ahash_alignmask(ahash) &
	32	~(crypto_tfm_ctx_alignment() - 1));
	33
	34	len = ALIGN(len, crypto_tfm_ctx_alignment());
	35
	36	len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
	37	len = ALIGN(len, __alignof__(struct scatterlist));
	38
	39	len += sizeof(struct scatterlist) * nfrags;
	40
	41	return kmalloc(len, GFP_ATOMIC);
	42	}
	43
	44	static inline u8 ah_tmp_auth(void tmp, unsigned int offset)
	45	{
	46	return tmp + offset;
	47	}
	48
	49	static inline u8 ah_tmp_icv(struct crypto_ahash ahash, void *tmp,
	50	unsigned int offset)
	51	{
	52	return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
	53	}
	54
	55	static inline struct ahash_request ah_tmp_req(struct crypto_ahash ahash,
	56	u8 *icv)
	57	{
	58	struct ahash_request *req;
	59
	60	req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
	61	crypto_tfm_ctx_alignment());
	62
	63	ahash_request_set_tfm(req, ahash);
	64
	65	return req;
	66	}
	67
	68	static inline struct scatterlist ah_req_sg(struct crypto_ahash ahash,
	69	struct ahash_request *req)
	70	{
	71	return (void *)ALIGN((unsigned long)(req + 1) +
	72	crypto_ahash_reqsize(ahash),
	73	__alignof__(struct scatterlist));
	74	}
1da177e4 LT	75
	76	/* Clear mutable options and find final destination to substitute
	77	* into IP header for icv calculation. Options are already checked
	78	* for validity, so paranoia is not required. */
	79
b71d1d42	80	static int ip_clear_mutable_options(const struct iphdr iph, __be32 daddr)
1da177e4	81	{
5e73ea1a	82	unsigned char optptr = (unsigned char )(iph+1);
1da177e4 LT	83	int l = iph->ihl*4 - sizeof(struct iphdr);
	84	int optlen;
	85
	86	while (l > 0) {
	87	switch (*optptr) {
	88	case IPOPT_END:
	89	return 0;
	90	case IPOPT_NOOP:
	91	l--;
	92	optptr++;
	93	continue;
	94	}
	95	optlen = optptr[1];
	96	if (optlen<2 \|\| optlen>l)
	97	return -EINVAL;
	98	switch (*optptr) {
	99	case IPOPT_SEC:
	100	case 0x85: /* Some "Extended Security" crap. */
11a03f78	101	case IPOPT_CIPSO:
1da177e4 LT	102	case IPOPT_RA:
	103	case 0x80\|21: /* RFC1770 */
	104	break;
	105	case IPOPT_LSRR:
	106	case IPOPT_SSRR:
	107	if (optlen < 6)
	108	return -EINVAL;
	109	memcpy(daddr, optptr+optlen-4, 4);
	110	/* Fall through */
	111	default:
96fe1c02	112	memset(optptr, 0, optlen);
1da177e4 LT	113	}
	114	l -= optlen;
	115	optptr += optlen;
	116	}
	117	return 0;
	118	}
	119
dff3bb06 SK	120	static void ah_output_done(struct crypto_async_request *base, int err)
	121	{
	122	u8 *icv;
	123	struct iphdr *iph;
	124	struct sk_buff *skb = base->data;
	125	struct xfrm_state *x = skb_dst(skb)->xfrm;
	126	struct ah_data *ahp = x->data;
	127	struct iphdr *top_iph = ip_hdr(skb);
	128	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	129	int ihl = ip_hdrlen(skb);
	130
	131	iph = AH_SKB_CB(skb)->tmp;
	132	icv = ah_tmp_icv(ahp->ahash, iph, ihl);
	133	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
	134
	135	top_iph->tos = iph->tos;
	136	top_iph->ttl = iph->ttl;
	137	top_iph->frag_off = iph->frag_off;
	138	if (top_iph->ihl != 5) {
	139	top_iph->daddr = iph->daddr;
	140	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	141	}
	142
dff3bb06 SK	143	kfree(AH_SKB_CB(skb)->tmp);
	144	xfrm_output_resume(skb, err);
	145	}
	146
1da177e4 LT	147	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	148	{
	149	int err;
dff3bb06 SK	150	int nfrags;
	151	int ihl;
	152	u8 *icv;
	153	struct sk_buff *trailer;
	154	struct crypto_ahash *ahash;
	155	struct ahash_request *req;
	156	struct scatterlist *sg;
1da177e4 LT	157	struct iphdr iph, top_iph;
	158	struct ip_auth_hdr *ah;
	159	struct ah_data *ahp;
d4d573d0 FD	160	int seqhi_len = 0;
	161	__be32 *seqhi;
	162	int sglists = 0;
	163	struct scatterlist *seqhisg;
dff3bb06 SK	164
	165	ahp = x->data;
	166	ahash = ahp->ahash;
	167
	168	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	169	goto out;
	170	nfrags = err;
1da177e4	171
7b277b1a	172	skb_push(skb, -skb_network_offset(skb));
dff3bb06 SK	173	ah = ip_auth_hdr(skb);
	174	ihl = ip_hdrlen(skb);
	175
d4d573d0 FD	176	if (x->props.flags & XFRM_STATE_ESN) {
	177	sglists = 1;
	178	seqhi_len = sizeof(*seqhi);
	179	}
dff3bb06	180	err = -ENOMEM;
d4d573d0	181	iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
dff3bb06 SK	182	if (!iph)
dff3bb06 SK	183	goto out;
d4d573d0 FD	184	seqhi = (__be32 )((char )iph + ihl);
d4d573d0 FD	185	icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
dff3bb06 SK	186	req = ah_tmp_req(ahash, icv);
dff3bb06 SK	187	sg = ah_req_sg(ahash, req);
d4d573d0	188	seqhisg = sg + nfrags;
dff3bb06 SK	189
	190	memset(ah->auth_data, 0, ahp->icv_trunc_len);
	191
eddc9ec5	192	top_iph = ip_hdr(skb);
1da177e4 LT	193
	194	iph->tos = top_iph->tos;
	195	iph->ttl = top_iph->ttl;
	196	iph->frag_off = top_iph->frag_off;
	197
	198	if (top_iph->ihl != 5) {
	199	iph->daddr = top_iph->daddr;
	200	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	201	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	202	if (err)
dff3bb06	203	goto out_free;
1da177e4 LT	204	}
1da177e4 LT	205
37fedd3a HX	206	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	207	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	208
	209	top_iph->tos = 0;
	210	top_iph->tot_len = htons(skb->len);
	211	top_iph->frag_off = 0;
	212	top_iph->ttl = 0;
1da177e4 LT	213	top_iph->check = 0;
1da177e4 LT	214
fa9921e4 ND	215	if (x->props.flags & XFRM_STATE_ALIGN4)
	216	ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
	217	else
	218	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	219
	220	ah->reserved = 0;
	221	ah->spi = x->id.spi;
1ce3644a	222	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
b7c6538c	223
d4d573d0	224	sg_init_table(sg, nfrags + sglists);
3f297707 JD	225	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	226	if (unlikely(err < 0))
	227	goto out_free;
b7c6538c	228
d4d573d0 FD	229	if (x->props.flags & XFRM_STATE_ESN) {
	230	/* Attach seqhi sg right after packet payload */
	231	*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
	232	sg_set_buf(seqhisg, seqhi, seqhi_len);
	233	}
	234	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
dff3bb06 SK	235	ahash_request_set_callback(req, 0, ah_output_done, skb);
	236
	237	AH_SKB_CB(skb)->tmp = iph;
	238
	239	err = crypto_ahash_digest(req);
	240	if (err) {
	241	if (err == -EINPROGRESS)
	242	goto out;
	243
068c2e70	244	if (err == -ENOSPC)
dff3bb06 SK	245	err = NET_XMIT_DROP;
	246	goto out_free;
	247	}
	248
	249	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
1da177e4 LT	250
	251	top_iph->tos = iph->tos;
	252	top_iph->ttl = iph->ttl;
	253	top_iph->frag_off = iph->frag_off;
	254	if (top_iph->ihl != 5) {
	255	top_iph->daddr = iph->daddr;
	256	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	257	}
	258
dff3bb06 SK	259	out_free:
	260	kfree(iph);
	261	out:
1da177e4 LT	262	return err;
	263	}
	264
dff3bb06 SK	265	static void ah_input_done(struct crypto_async_request *base, int err)
	266	{
	267	u8 *auth_data;
	268	u8 *icv;
	269	struct iphdr *work_iph;
	270	struct sk_buff *skb = base->data;
	271	struct xfrm_state *x = xfrm_input_state(skb);
	272	struct ah_data *ahp = x->data;
	273	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	274	int ihl = ip_hdrlen(skb);
	275	int ah_hlen = (ah->hdrlen + 2) << 2;
	276
ebd89a2d GBY	277	if (err)
	278	goto out;
	279
dff3bb06 SK	280	work_iph = AH_SKB_CB(skb)->tmp;
	281	auth_data = ah_tmp_auth(work_iph, ihl);
	282	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
	283
67df58a3	284	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
dff3bb06 SK	285	if (err)
	286	goto out;
	287
b7ea81a5 NB	288	err = ah->nexthdr;
b7ea81a5 NB	289
dff3bb06 SK	290	skb->network_header += ah_hlen;
	291	memcpy(skb_network_header(skb), work_iph, ihl);
	292	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	293
	294	if (x->props.mode == XFRM_MODE_TUNNEL)
	295	skb_reset_transport_header(skb);
	296	else
	297	skb_set_transport_header(skb, -ihl);
dff3bb06 SK	298	out:
	299	kfree(AH_SKB_CB(skb)->tmp);
	300	xfrm_input_resume(skb, err);
	301	}
	302
e695633e	303	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	304	{
1da177e4 LT	305	int ah_hlen;
31a4ab93	306	int ihl;
631a6698	307	int nexthdr;
dff3bb06 SK	308	int nfrags;
	309	u8 *auth_data;
	310	u8 *icv;
	311	struct sk_buff *trailer;
	312	struct crypto_ahash *ahash;
	313	struct ahash_request *req;
	314	struct scatterlist *sg;
	315	struct iphdr iph, work_iph;
1da177e4 LT	316	struct ip_auth_hdr *ah;
1da177e4 LT	317	struct ah_data *ahp;
dff3bb06	318	int err = -ENOMEM;
d8b2a860 FD	319	int seqhi_len = 0;
	320	__be32 *seqhi;
	321	int sglists = 0;
	322	struct scatterlist *seqhisg;
1da177e4	323
87bdc48d	324	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	325	goto out;
1da177e4 LT	326
87bdc48d	327	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	328	ahp = x->data;
dff3bb06 SK	329	ahash = ahp->ahash;
dff3bb06 SK	330
631a6698	331	nexthdr = ah->nexthdr;
1da177e4	332	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	333
fa9921e4 ND	334	if (x->props.flags & XFRM_STATE_ALIGN4) {
	335	if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
	336	ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
	337	goto out;
	338	} else {
	339	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	340	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
	341	goto out;
	342	}
1da177e4 LT	343
	344	if (!pskb_may_pull(skb, ah_hlen))
	345	goto out;
	346
	347	/* We are going to _remove_ AH header to keep sockets happy,
	348	* so... Later this can change. */
14bbd6a5	349	if (skb_unclone(skb, GFP_ATOMIC))
1da177e4 LT	350	goto out;
	351
	352	skb->ip_summed = CHECKSUM_NONE;
	353
dff3bb06 SK	354
	355	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	356	goto out;
	357	nfrags = err;
	358
4b0ef1f2 DH	359	ah = (struct ip_auth_hdr *)skb->data;
	360	iph = ip_hdr(skb);
	361	ihl = ip_hdrlen(skb);
	362
d8b2a860 FD	363	if (x->props.flags & XFRM_STATE_ESN) {
	364	sglists = 1;
	365	seqhi_len = sizeof(*seqhi);
	366	}
	367
	368	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
	369	ahp->icv_trunc_len + seqhi_len);
94c10f0e DM	370	if (!work_iph) {
94c10f0e DM	371	err = -ENOMEM;
dff3bb06	372	goto out;
94c10f0e	373	}
dff3bb06	374
d8b2a860 FD	375	seqhi = (__be32 )((char )work_iph + ihl);
d8b2a860 FD	376	auth_data = ah_tmp_auth(seqhi, seqhi_len);
dff3bb06 SK	377	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
	378	req = ah_tmp_req(ahash, icv);
	379	sg = ah_req_sg(ahash, req);
d8b2a860	380	seqhisg = sg + nfrags;
1da177e4	381
dff3bb06 SK	382	memcpy(work_iph, iph, ihl);
	383	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	384	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	385
	386	iph->ttl = 0;
	387	iph->tos = 0;
	388	iph->frag_off = 0;
	389	iph->check = 0;
31a4ab93	390	if (ihl > sizeof(*iph)) {
d5a0a1e3	391	__be32 dummy;
dff3bb06 SK	392	err = ip_clear_mutable_options(iph, &dummy);
	393	if (err)
	394	goto out_free;
1da177e4	395	}
0ebea8ef	396
dff3bb06	397	skb_push(skb, ihl);
e905a9ed	398
d8b2a860	399	sg_init_table(sg, nfrags + sglists);
3f297707 JD	400	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	401	if (unlikely(err < 0))
	402	goto out_free;
dff3bb06	403
d8b2a860 FD	404	if (x->props.flags & XFRM_STATE_ESN) {
	405	/* Attach seqhi sg right after packet payload */
	406	*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
	407	sg_set_buf(seqhisg, seqhi, seqhi_len);
	408	}
	409	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
dff3bb06 SK	410	ahash_request_set_callback(req, 0, ah_input_done, skb);
	411
	412	AH_SKB_CB(skb)->tmp = work_iph;
	413
	414	err = crypto_ahash_digest(req);
	415	if (err) {
	416	if (err == -EINPROGRESS)
	417	goto out;
	418
dff3bb06	419	goto out_free;
1da177e4	420	}
0ebea8ef	421
67df58a3	422	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
0ebea8ef	423	if (err)
dff3bb06	424	goto out_free;
0ebea8ef	425
b0e380b1	426	skb->network_header += ah_hlen;
dff3bb06	427	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	428	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	429	if (x->props.mode == XFRM_MODE_TUNNEL)
	430	skb_reset_transport_header(skb);
	431	else
	432	skb_set_transport_header(skb, -ihl);
1da177e4	433
dff3bb06	434	err = nexthdr;
1da177e4	435
dff3bb06 SK	436	out_free:
dff3bb06 SK	437	kfree (work_iph);
1da177e4	438	out:
07d4ee58	439	return err;
1da177e4 LT	440	}
1da177e4 LT	441
e5b56454	442	static int ah4_err(struct sk_buff *skb, u32 info)
1da177e4	443	{
4fb236ba	444	struct net *net = dev_net(skb->dev);
b71d1d42	445	const struct iphdr iph = (const struct iphdr )skb->data;
d9319100	446	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	447	struct xfrm_state *x;
1da177e4 LT	448
55be7a9c DM	449	switch (icmp_hdr(skb)->type) {
	450	case ICMP_DEST_UNREACH:
	451	if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
e5b56454	452	return 0;
55be7a9c DM	453	case ICMP_REDIRECT:
	454	break;
	455	default:
e5b56454	456	return 0;
55be7a9c	457	}
1da177e4	458
b71d1d42 ED	459	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
b71d1d42 ED	460	ah->spi, IPPROTO_AH, AF_INET);
1da177e4	461	if (!x)
e5b56454	462	return 0;
55be7a9c	463
387aa65a	464	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
d888f396	465	ipv4_update_pmtu(skb, net, info, 0, IPPROTO_AH);
387aa65a	466	else
1042caa7	467	ipv4_redirect(skb, net, 0, IPPROTO_AH);
1da177e4	468	xfrm_state_put(x);
e5b56454 SK	469
e5b56454 SK	470	return 0;
1da177e4 LT	471	}
1da177e4 LT	472
72cb6962	473	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	474	{
	475	struct ah_data *ahp = NULL;
	476	struct xfrm_algo_desc *aalg_desc;
dff3bb06	477	struct crypto_ahash *ahash;
1da177e4 LT	478
	479	if (!x->aalg)
	480	goto error;
	481
1da177e4 LT	482	if (x->encap)
	483	goto error;
	484
0da974f4	485	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	486	if (!ahp)
1da177e4 LT	487	return -ENOMEM;
1da177e4 LT	488
dff3bb06 SK	489	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
dff3bb06 SK	490	if (IS_ERR(ahash))
07d4ee58 HX	491	goto error;
07d4ee58 HX	492
dff3bb06 SK	493	ahp->ahash = ahash;
	494	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
	495	(x->aalg->alg_key_len + 7) / 8))
1da177e4	496	goto error;
e905a9ed	497
1da177e4 LT	498	/*
	499	* Lookup the algorithm description maintained by xfrm_algo,
	500	* verify crypto transform properties, and store information
	501	* we need for AH processing. This lookup cannot fail here
dff3bb06	502	* after a successful crypto_alloc_ahash().
1da177e4 LT	503	*/
	504	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	505	BUG_ON(!aalg_desc);
	506
	507	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	508	crypto_ahash_digestsize(ahash)) {
afd46503 JP	509	pr_info("%s: %s digestsize %u != %hu\n",
	510	__func__, x->aalg->alg_name,
	511	crypto_ahash_digestsize(ahash),
	512	aalg_desc->uinfo.auth.icv_fullbits / 8);
1da177e4 LT	513	goto error;
1da177e4 LT	514	}
e905a9ed	515
1da177e4	516	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	517	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	518
fa9921e4 ND	519	if (x->props.flags & XFRM_STATE_ALIGN4)
	520	x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
	521	ahp->icv_trunc_len);
	522	else
	523	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
	524	ahp->icv_trunc_len);
7e49e6de	525	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	526	x->props.header_len += sizeof(struct iphdr);
	527	x->data = ahp;
	528
	529	return 0;
	530
	531	error:
	532	if (ahp) {
dff3bb06	533	crypto_free_ahash(ahp->ahash);
1da177e4 LT	534	kfree(ahp);
	535	}
	536	return -EINVAL;
	537	}
	538
	539	static void ah_destroy(struct xfrm_state *x)
	540	{
	541	struct ah_data *ahp = x->data;
	542
	543	if (!ahp)
	544	return;
	545
dff3bb06	546	crypto_free_ahash(ahp->ahash);
1da177e4 LT	547	kfree(ahp);
	548	}
	549
e5b56454 SK	550	static int ah4_rcv_cb(struct sk_buff *skb, int err)
	551	{
	552	return 0;
	553	}
1da177e4	554
533cb5b0	555	static const struct xfrm_type ah_type =
1da177e4 LT	556	{
	557	.description = "AH4",
	558	.owner = THIS_MODULE,
	559	.proto = IPPROTO_AH,
436a0a40	560	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	561	.init_state = ah_init_state,
	562	.destructor = ah_destroy,
	563	.input = ah_input,
	564	.output = ah_output
	565	};
	566
e5b56454	567	static struct xfrm4_protocol ah4_protocol = {
1da177e4	568	.handler = xfrm4_rcv,
e5b56454 SK	569	.input_handler = xfrm_input,
e5b56454 SK	570	.cb_handler = ah4_rcv_cb,
1da177e4	571	.err_handler = ah4_err,
e5b56454	572	.priority = 0,
1da177e4 LT	573	};
	574
	575	static int __init ah4_init(void)
	576	{
	577	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
058bd4d2	578	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	579	return -EAGAIN;
1da177e4 LT	580	}
e5b56454	581	if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
058bd4d2	582	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	583	xfrm_unregister_type(&ah_type, AF_INET);
	584	return -EAGAIN;
	585	}
	586	return 0;
	587	}
	588
	589	static void __exit ah4_fini(void)
	590	{
e5b56454	591	if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
058bd4d2	592	pr_info("%s: can't remove protocol\n", __func__);
4f518e80	593	xfrm_unregister_type(&ah_type, AF_INET);
1da177e4 LT	594	}
	595
	596	module_init(ah4_init);
	597	module_exit(ah4_fini);
	598	MODULE_LICENSE("GPL");
d3d6dd3a	599	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);