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

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

#include <crypto/hash.h>
#include <crypto/utils.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);

	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(void *tmp, unsigned int offset)
{
	return tmp + offset;
}

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);
			fallthrough;
		default:
			memset(optptr, 0, optlen);
		}
		l -= optlen;
		optptr += optlen;
	}
	return 0;
}

static void ah_output_done(void *data, int err)
{
	u8 *icv;
	struct iphdr *iph;
	struct sk_buff *skb = 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(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->sk, 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(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(void *data, int err)
{
	u8 *auth_data;
	u8 *icv;
	struct iphdr *work_iph;
	struct sk_buff *skb = 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(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(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;
		break;
	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 netlink_ext_ack *extack)
{
	struct ah_data *ahp = NULL;
	struct xfrm_algo_desc *aalg_desc;
	struct crypto_ahash *ahash;

	if (!x->aalg) {
		NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
		goto error;
	}

	if (x->encap) {
		NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
		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)) {
		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
		goto error;
	}

	ahp->ahash = ahash;
	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
				(x->aalg->alg_key_len + 7) / 8)) {
		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
		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)) {
		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
		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 =
{
	.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_DESCRIPTION("IPv4 AH transformation library");
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
dff3bb06	4	#include <crypto/hash.h>
c66218cc	5	#include <crypto/utils.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
e77f5dd7	30	len = size + crypto_ahash_digestsize(ahash);
dff3bb06 SK	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
e77f5dd7	47	static inline u8 ah_tmp_icv(void tmp, unsigned int offset)
dff3bb06	48	{
e77f5dd7	49	return tmp + offset;
dff3bb06 SK	50	}
	51
	52	static inline struct ahash_request ah_tmp_req(struct crypto_ahash ahash,
	53	u8 *icv)
	54	{
	55	struct ahash_request *req;
	56
	57	req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
	58	crypto_tfm_ctx_alignment());
	59
	60	ahash_request_set_tfm(req, ahash);
	61
	62	return req;
	63	}
	64
	65	static inline struct scatterlist ah_req_sg(struct crypto_ahash ahash,
	66	struct ahash_request *req)
	67	{
	68	return (void *)ALIGN((unsigned long)(req + 1) +
	69	crypto_ahash_reqsize(ahash),
	70	__alignof__(struct scatterlist));
	71	}
1da177e4 LT	72
	73	/* Clear mutable options and find final destination to substitute
	74	* into IP header for icv calculation. Options are already checked
	75	* for validity, so paranoia is not required. */
	76
b71d1d42	77	static int ip_clear_mutable_options(const struct iphdr iph, __be32 daddr)
1da177e4	78	{
5e73ea1a	79	unsigned char optptr = (unsigned char )(iph+1);
1da177e4 LT	80	int l = iph->ihl*4 - sizeof(struct iphdr);
	81	int optlen;
	82
	83	while (l > 0) {
	84	switch (*optptr) {
	85	case IPOPT_END:
	86	return 0;
	87	case IPOPT_NOOP:
	88	l--;
	89	optptr++;
	90	continue;
	91	}
	92	optlen = optptr[1];
	93	if (optlen<2 \|\| optlen>l)
	94	return -EINVAL;
	95	switch (*optptr) {
	96	case IPOPT_SEC:
	97	case 0x85: /* Some "Extended Security" crap. */
11a03f78	98	case IPOPT_CIPSO:
1da177e4 LT	99	case IPOPT_RA:
	100	case 0x80\|21: /* RFC1770 */
	101	break;
	102	case IPOPT_LSRR:
	103	case IPOPT_SSRR:
	104	if (optlen < 6)
	105	return -EINVAL;
	106	memcpy(daddr, optptr+optlen-4, 4);
a8eceea8	107	fallthrough;
1da177e4	108	default:
96fe1c02	109	memset(optptr, 0, optlen);
1da177e4 LT	110	}
	111	l -= optlen;
	112	optptr += optlen;
	113	}
	114	return 0;
	115	}
	116
fd5dabf7	117	static void ah_output_done(void *data, int err)
dff3bb06 SK	118	{
	119	u8 *icv;
	120	struct iphdr *iph;
fd5dabf7	121	struct sk_buff *skb = data;
dff3bb06 SK	122	struct xfrm_state *x = skb_dst(skb)->xfrm;
	123	struct ah_data *ahp = x->data;
	124	struct iphdr *top_iph = ip_hdr(skb);
	125	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	126	int ihl = ip_hdrlen(skb);
	127
	128	iph = AH_SKB_CB(skb)->tmp;
e77f5dd7	129	icv = ah_tmp_icv(iph, ihl);
dff3bb06 SK	130	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
	131
	132	top_iph->tos = iph->tos;
	133	top_iph->ttl = iph->ttl;
	134	top_iph->frag_off = iph->frag_off;
	135	if (top_iph->ihl != 5) {
	136	top_iph->daddr = iph->daddr;
	137	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	138	}
	139
dff3bb06	140	kfree(AH_SKB_CB(skb)->tmp);
9ab1265d	141	xfrm_output_resume(skb->sk, skb, err);
dff3bb06 SK	142	}
dff3bb06 SK	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;
d4d573d0 FD	157	int seqhi_len = 0;
	158	__be32 *seqhi;
	159	int sglists = 0;
	160	struct scatterlist *seqhisg;
dff3bb06 SK	161
	162	ahp = x->data;
	163	ahash = ahp->ahash;
	164
	165	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	166	goto out;
	167	nfrags = err;
1da177e4	168
7b277b1a	169	skb_push(skb, -skb_network_offset(skb));
dff3bb06 SK	170	ah = ip_auth_hdr(skb);
	171	ihl = ip_hdrlen(skb);
	172
d4d573d0 FD	173	if (x->props.flags & XFRM_STATE_ESN) {
	174	sglists = 1;
	175	seqhi_len = sizeof(*seqhi);
	176	}
dff3bb06	177	err = -ENOMEM;
d4d573d0	178	iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
dff3bb06 SK	179	if (!iph)
dff3bb06 SK	180	goto out;
d4d573d0	181	seqhi = (__be32 )((char )iph + ihl);
e77f5dd7	182	icv = ah_tmp_icv(seqhi, seqhi_len);
dff3bb06 SK	183	req = ah_tmp_req(ahash, icv);
dff3bb06 SK	184	sg = ah_req_sg(ahash, req);
d4d573d0	185	seqhisg = sg + nfrags;
dff3bb06 SK	186
	187	memset(ah->auth_data, 0, ahp->icv_trunc_len);
	188
eddc9ec5	189	top_iph = ip_hdr(skb);
1da177e4 LT	190
	191	iph->tos = top_iph->tos;
	192	iph->ttl = top_iph->ttl;
	193	iph->frag_off = top_iph->frag_off;
	194
	195	if (top_iph->ihl != 5) {
	196	iph->daddr = top_iph->daddr;
	197	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	198	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
	199	if (err)
dff3bb06	200	goto out_free;
1da177e4 LT	201	}
1da177e4 LT	202
37fedd3a HX	203	ah->nexthdr = *skb_mac_header(skb);
37fedd3a HX	204	*skb_mac_header(skb) = IPPROTO_AH;
1da177e4 LT	205
	206	top_iph->tos = 0;
	207	top_iph->tot_len = htons(skb->len);
	208	top_iph->frag_off = 0;
	209	top_iph->ttl = 0;
1da177e4 LT	210	top_iph->check = 0;
1da177e4 LT	211
fa9921e4 ND	212	if (x->props.flags & XFRM_STATE_ALIGN4)
	213	ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
	214	else
	215	ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
1da177e4 LT	216
	217	ah->reserved = 0;
	218	ah->spi = x->id.spi;
1ce3644a	219	ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
b7c6538c	220
d4d573d0	221	sg_init_table(sg, nfrags + sglists);
3f297707 JD	222	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	223	if (unlikely(err < 0))
	224	goto out_free;
b7c6538c	225
d4d573d0 FD	226	if (x->props.flags & XFRM_STATE_ESN) {
	227	/* Attach seqhi sg right after packet payload */
	228	*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
	229	sg_set_buf(seqhisg, seqhi, seqhi_len);
	230	}
	231	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
dff3bb06 SK	232	ahash_request_set_callback(req, 0, ah_output_done, skb);
	233
	234	AH_SKB_CB(skb)->tmp = iph;
	235
	236	err = crypto_ahash_digest(req);
	237	if (err) {
	238	if (err == -EINPROGRESS)
	239	goto out;
	240
068c2e70	241	if (err == -ENOSPC)
dff3bb06 SK	242	err = NET_XMIT_DROP;
	243	goto out_free;
	244	}
	245
	246	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
1da177e4 LT	247
	248	top_iph->tos = iph->tos;
	249	top_iph->ttl = iph->ttl;
	250	top_iph->frag_off = iph->frag_off;
	251	if (top_iph->ihl != 5) {
	252	top_iph->daddr = iph->daddr;
	253	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	254	}
	255
dff3bb06 SK	256	out_free:
	257	kfree(iph);
	258	out:
1da177e4 LT	259	return err;
	260	}
	261
fd5dabf7	262	static void ah_input_done(void *data, int err)
dff3bb06 SK	263	{
	264	u8 *auth_data;
	265	u8 *icv;
	266	struct iphdr *work_iph;
fd5dabf7	267	struct sk_buff *skb = data;
dff3bb06 SK	268	struct xfrm_state *x = xfrm_input_state(skb);
	269	struct ah_data *ahp = x->data;
	270	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
	271	int ihl = ip_hdrlen(skb);
	272	int ah_hlen = (ah->hdrlen + 2) << 2;
	273
ebd89a2d GBY	274	if (err)
	275	goto out;
	276
dff3bb06 SK	277	work_iph = AH_SKB_CB(skb)->tmp;
dff3bb06 SK	278	auth_data = ah_tmp_auth(work_iph, ihl);
e77f5dd7	279	icv = ah_tmp_icv(auth_data, ahp->icv_trunc_len);
dff3bb06	280
67df58a3	281	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
dff3bb06 SK	282	if (err)
	283	goto out;
	284
b7ea81a5 NB	285	err = ah->nexthdr;
b7ea81a5 NB	286
dff3bb06 SK	287	skb->network_header += ah_hlen;
	288	memcpy(skb_network_header(skb), work_iph, ihl);
	289	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	290
	291	if (x->props.mode == XFRM_MODE_TUNNEL)
	292	skb_reset_transport_header(skb);
	293	else
	294	skb_set_transport_header(skb, -ihl);
dff3bb06 SK	295	out:
	296	kfree(AH_SKB_CB(skb)->tmp);
	297	xfrm_input_resume(skb, err);
	298	}
	299
e695633e	300	static int ah_input(struct xfrm_state x, struct sk_buff skb)
1da177e4 LT	301	{
1da177e4 LT	302	int ah_hlen;
31a4ab93	303	int ihl;
631a6698	304	int nexthdr;
dff3bb06 SK	305	int nfrags;
	306	u8 *auth_data;
	307	u8 *icv;
	308	struct sk_buff *trailer;
	309	struct crypto_ahash *ahash;
	310	struct ahash_request *req;
	311	struct scatterlist *sg;
	312	struct iphdr iph, work_iph;
1da177e4 LT	313	struct ip_auth_hdr *ah;
1da177e4 LT	314	struct ah_data *ahp;
dff3bb06	315	int err = -ENOMEM;
d8b2a860 FD	316	int seqhi_len = 0;
	317	__be32 *seqhi;
	318	int sglists = 0;
	319	struct scatterlist *seqhisg;
1da177e4	320
87bdc48d	321	if (!pskb_may_pull(skb, sizeof(*ah)))
1da177e4 LT	322	goto out;
1da177e4 LT	323
87bdc48d	324	ah = (struct ip_auth_hdr *)skb->data;
1da177e4	325	ahp = x->data;
dff3bb06 SK	326	ahash = ahp->ahash;
dff3bb06 SK	327
631a6698	328	nexthdr = ah->nexthdr;
1da177e4	329	ah_hlen = (ah->hdrlen + 2) << 2;
e905a9ed	330
fa9921e4 ND	331	if (x->props.flags & XFRM_STATE_ALIGN4) {
	332	if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
	333	ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
	334	goto out;
	335	} else {
	336	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
	337	ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
	338	goto out;
	339	}
1da177e4 LT	340
	341	if (!pskb_may_pull(skb, ah_hlen))
	342	goto out;
	343
	344	/* We are going to _remove_ AH header to keep sockets happy,
	345	* so... Later this can change. */
14bbd6a5	346	if (skb_unclone(skb, GFP_ATOMIC))
1da177e4 LT	347	goto out;
	348
	349	skb->ip_summed = CHECKSUM_NONE;
	350
dff3bb06 SK	351
	352	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
	353	goto out;
	354	nfrags = err;
	355
4b0ef1f2 DH	356	ah = (struct ip_auth_hdr *)skb->data;
	357	iph = ip_hdr(skb);
	358	ihl = ip_hdrlen(skb);
	359
d8b2a860 FD	360	if (x->props.flags & XFRM_STATE_ESN) {
	361	sglists = 1;
	362	seqhi_len = sizeof(*seqhi);
	363	}
	364
	365	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
	366	ahp->icv_trunc_len + seqhi_len);
94c10f0e DM	367	if (!work_iph) {
94c10f0e DM	368	err = -ENOMEM;
dff3bb06	369	goto out;
94c10f0e	370	}
dff3bb06	371
d8b2a860 FD	372	seqhi = (__be32 )((char )work_iph + ihl);
d8b2a860 FD	373	auth_data = ah_tmp_auth(seqhi, seqhi_len);
e77f5dd7	374	icv = ah_tmp_icv(auth_data, ahp->icv_trunc_len);
dff3bb06 SK	375	req = ah_tmp_req(ahash, icv);
dff3bb06 SK	376	sg = ah_req_sg(ahash, req);
d8b2a860	377	seqhisg = sg + nfrags;
1da177e4	378
dff3bb06 SK	379	memcpy(work_iph, iph, ihl);
	380	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
	381	memset(ah->auth_data, 0, ahp->icv_trunc_len);
1da177e4 LT	382
	383	iph->ttl = 0;
	384	iph->tos = 0;
	385	iph->frag_off = 0;
	386	iph->check = 0;
31a4ab93	387	if (ihl > sizeof(*iph)) {
d5a0a1e3	388	__be32 dummy;
dff3bb06 SK	389	err = ip_clear_mutable_options(iph, &dummy);
	390	if (err)
	391	goto out_free;
1da177e4	392	}
0ebea8ef	393
dff3bb06	394	skb_push(skb, ihl);
e905a9ed	395
d8b2a860	396	sg_init_table(sg, nfrags + sglists);
3f297707 JD	397	err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
	398	if (unlikely(err < 0))
	399	goto out_free;
dff3bb06	400
d8b2a860 FD	401	if (x->props.flags & XFRM_STATE_ESN) {
	402	/* Attach seqhi sg right after packet payload */
	403	*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
	404	sg_set_buf(seqhisg, seqhi, seqhi_len);
	405	}
	406	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
dff3bb06 SK	407	ahash_request_set_callback(req, 0, ah_input_done, skb);
	408
	409	AH_SKB_CB(skb)->tmp = work_iph;
	410
	411	err = crypto_ahash_digest(req);
	412	if (err) {
	413	if (err == -EINPROGRESS)
	414	goto out;
	415
dff3bb06	416	goto out_free;
1da177e4	417	}
0ebea8ef	418
67df58a3	419	err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
0ebea8ef	420	if (err)
dff3bb06	421	goto out_free;
0ebea8ef	422
b0e380b1	423	skb->network_header += ah_hlen;
dff3bb06	424	memcpy(skb_network_header(skb), work_iph, ihl);
31a4ab93	425	__skb_pull(skb, ah_hlen + ihl);
7143dfac LR	426	if (x->props.mode == XFRM_MODE_TUNNEL)
	427	skb_reset_transport_header(skb);
	428	else
	429	skb_set_transport_header(skb, -ihl);
1da177e4	430
dff3bb06	431	err = nexthdr;
1da177e4	432
dff3bb06 SK	433	out_free:
dff3bb06 SK	434	kfree (work_iph);
1da177e4	435	out:
07d4ee58	436	return err;
1da177e4 LT	437	}
1da177e4 LT	438
e5b56454	439	static int ah4_err(struct sk_buff *skb, u32 info)
1da177e4	440	{
4fb236ba	441	struct net *net = dev_net(skb->dev);
b71d1d42	442	const struct iphdr iph = (const struct iphdr )skb->data;
d9319100	443	struct ip_auth_hdr ah = (struct ip_auth_hdr )(skb->data+(iph->ihl<<2));
1da177e4 LT	444	struct xfrm_state *x;
1da177e4 LT	445
55be7a9c DM	446	switch (icmp_hdr(skb)->type) {
	447	case ICMP_DEST_UNREACH:
	448	if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
e5b56454	449	return 0;
79121184	450	break;
55be7a9c DM	451	case ICMP_REDIRECT:
	452	break;
	453	default:
e5b56454	454	return 0;
55be7a9c	455	}
1da177e4	456
b71d1d42 ED	457	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
b71d1d42 ED	458	ah->spi, IPPROTO_AH, AF_INET);
1da177e4	459	if (!x)
e5b56454	460	return 0;
55be7a9c	461
387aa65a	462	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
d888f396	463	ipv4_update_pmtu(skb, net, info, 0, IPPROTO_AH);
387aa65a	464	else
1042caa7	465	ipv4_redirect(skb, net, 0, IPPROTO_AH);
1da177e4	466	xfrm_state_put(x);
e5b56454 SK	467
e5b56454 SK	468	return 0;
1da177e4 LT	469	}
1da177e4 LT	470
e1e10b44	471	static int ah_init_state(struct xfrm_state x, struct netlink_ext_ack extack)
1da177e4 LT	472	{
	473	struct ah_data *ahp = NULL;
	474	struct xfrm_algo_desc *aalg_desc;
dff3bb06	475	struct crypto_ahash *ahash;
1da177e4	476
ef87a4f8 SD	477	if (!x->aalg) {
ef87a4f8 SD	478	NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
1da177e4	479	goto error;
ef87a4f8	480	}
1da177e4	481
ef87a4f8 SD	482	if (x->encap) {
ef87a4f8 SD	483	NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
1da177e4	484	goto error;
ef87a4f8	485	}
1da177e4	486
0da974f4	487	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
dff3bb06	488	if (!ahp)
1da177e4 LT	489	return -ENOMEM;
1da177e4 LT	490
dff3bb06	491	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
ef87a4f8 SD	492	if (IS_ERR(ahash)) {
ef87a4f8 SD	493	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
07d4ee58	494	goto error;
ef87a4f8	495	}
07d4ee58	496
dff3bb06 SK	497	ahp->ahash = ahash;
dff3bb06 SK	498	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
ef87a4f8 SD	499	(x->aalg->alg_key_len + 7) / 8)) {
ef87a4f8 SD	500	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1da177e4	501	goto error;
ef87a4f8	502	}
e905a9ed	503
1da177e4 LT	504	/*
	505	* Lookup the algorithm description maintained by xfrm_algo,
	506	* verify crypto transform properties, and store information
	507	* we need for AH processing. This lookup cannot fail here
dff3bb06	508	* after a successful crypto_alloc_ahash().
1da177e4 LT	509	*/
	510	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	511	BUG_ON(!aalg_desc);
	512
	513	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
dff3bb06	514	crypto_ahash_digestsize(ahash)) {
ef87a4f8	515	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1da177e4 LT	516	goto error;
1da177e4 LT	517	}
e905a9ed	518
1da177e4	519	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
8f8a088c	520	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
e905a9ed	521
fa9921e4 ND	522	if (x->props.flags & XFRM_STATE_ALIGN4)
	523	x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
	524	ahp->icv_trunc_len);
	525	else
	526	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
	527	ahp->icv_trunc_len);
7e49e6de	528	if (x->props.mode == XFRM_MODE_TUNNEL)
1da177e4 LT	529	x->props.header_len += sizeof(struct iphdr);
	530	x->data = ahp;
	531
	532	return 0;
	533
	534	error:
	535	if (ahp) {
dff3bb06	536	crypto_free_ahash(ahp->ahash);
1da177e4 LT	537	kfree(ahp);
	538	}
	539	return -EINVAL;
	540	}
	541
	542	static void ah_destroy(struct xfrm_state *x)
	543	{
	544	struct ah_data *ahp = x->data;
	545
	546	if (!ahp)
	547	return;
	548
dff3bb06	549	crypto_free_ahash(ahp->ahash);
1da177e4 LT	550	kfree(ahp);
	551	}
	552
e5b56454 SK	553	static int ah4_rcv_cb(struct sk_buff *skb, int err)
	554	{
	555	return 0;
	556	}
1da177e4	557
533cb5b0	558	static const struct xfrm_type ah_type =
1da177e4	559	{
1da177e4 LT	560	.owner = THIS_MODULE,
1da177e4 LT	561	.proto = IPPROTO_AH,
436a0a40	562	.flags = XFRM_TYPE_REPLAY_PROT,
1da177e4 LT	563	.init_state = ah_init_state,
	564	.destructor = ah_destroy,
	565	.input = ah_input,
	566	.output = ah_output
	567	};
	568
e5b56454	569	static struct xfrm4_protocol ah4_protocol = {
1da177e4	570	.handler = xfrm4_rcv,
e5b56454 SK	571	.input_handler = xfrm_input,
e5b56454 SK	572	.cb_handler = ah4_rcv_cb,
1da177e4	573	.err_handler = ah4_err,
e5b56454	574	.priority = 0,
1da177e4 LT	575	};
	576
	577	static int __init ah4_init(void)
	578	{
	579	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
058bd4d2	580	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	581	return -EAGAIN;
1da177e4 LT	582	}
e5b56454	583	if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
058bd4d2	584	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	585	xfrm_unregister_type(&ah_type, AF_INET);
	586	return -EAGAIN;
	587	}
	588	return 0;
	589	}
	590
	591	static void __exit ah4_fini(void)
	592	{
e5b56454	593	if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
058bd4d2	594	pr_info("%s: can't remove protocol\n", __func__);
4f518e80	595	xfrm_unregister_type(&ah_type, AF_INET);
1da177e4 LT	596	}
	597
	598	module_init(ah4_init);
	599	module_exit(ah4_fini);
b058a5d2	600	MODULE_DESCRIPTION("IPv4 AH transformation library");
1da177e4	601	MODULE_LICENSE("GPL");
d3d6dd3a	602	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);