static struct sk_buff *__pfkey_xfrm_state2msg(const struct xfrm_state *x,
					      int add_keys, int hsc)
{
	struct sk_buff *skb;
	struct sadb_msg *hdr;
	struct sadb_sa *sa;
	struct sadb_lifetime *lifetime;
	struct sadb_address *addr;
	struct sadb_key *key;
	struct sadb_x_sa2 *sa2;
	struct sadb_x_sec_ctx *sec_ctx;
	struct xfrm_sec_ctx *xfrm_ctx;
	int ctx_size = 0;
	int size;
	int auth_key_size = 0;
	int encrypt_key_size = 0;
	int sockaddr_size;
	struct xfrm_encap_tmpl *natt = NULL;
	int mode;

	/* address family check */
	sockaddr_size = pfkey_sockaddr_size(x->props.family);
	if (!sockaddr_size)
		return ERR_PTR(-EINVAL);

	/* base, SA, (lifetime (HSC),) address(SD), (address(P),)
	   key(AE), (identity(SD),) (sensitivity)> */
	size = sizeof(struct sadb_msg) +sizeof(struct sadb_sa) +
		sizeof(struct sadb_lifetime) +
		((hsc & 1) ? sizeof(struct sadb_lifetime) : 0) +
		((hsc & 2) ? sizeof(struct sadb_lifetime) : 0) +
			sizeof(struct sadb_address)*2 +
				sockaddr_size*2 +
					sizeof(struct sadb_x_sa2);

	if ((xfrm_ctx = x->security)) {
		ctx_size = PFKEY_ALIGN8(xfrm_ctx->ctx_len);
		size += sizeof(struct sadb_x_sec_ctx) + ctx_size;
	}

	/* identity & sensitivity */
	if (!xfrm_addr_equal(&x->sel.saddr, &x->props.saddr, x->props.family))
		size += sizeof(struct sadb_address) + sockaddr_size;

	if (add_keys) {
		if (x->aalg && x->aalg->alg_key_len) {
			auth_key_size =
				PFKEY_ALIGN8((x->aalg->alg_key_len + 7) / 8);
			size += sizeof(struct sadb_key) + auth_key_size;
		}
		if (x->ealg && x->ealg->alg_key_len) {
			encrypt_key_size =
				PFKEY_ALIGN8((x->ealg->alg_key_len+7) / 8);
			size += sizeof(struct sadb_key) + encrypt_key_size;
		}
	}
	if (x->encap)
		natt = x->encap;

	if (natt && natt->encap_type) {
		size += sizeof(struct sadb_x_nat_t_type);
		size += sizeof(struct sadb_x_nat_t_port);
		size += sizeof(struct sadb_x_nat_t_port);
	}

	skb =  alloc_skb(size + 16, GFP_ATOMIC);
	if (skb == NULL)
		return ERR_PTR(-ENOBUFS);

	/* call should fill header later */
	hdr = (struct sadb_msg *) skb_put(skb, sizeof(struct sadb_msg));
	memset(hdr, 0, size);	/* XXX do we need this ? */
	hdr->sadb_msg_len = size / sizeof(uint64_t);

	/* sa */
	sa = (struct sadb_sa *)  skb_put(skb, sizeof(struct sadb_sa));
	sa->sadb_sa_len = sizeof(struct sadb_sa)/sizeof(uint64_t);
	sa->sadb_sa_exttype = SADB_EXT_SA;
	sa->sadb_sa_spi = x->id.spi;
	sa->sadb_sa_replay = x->props.replay_window;
	switch (x->km.state) {
	case XFRM_STATE_VALID:
		sa->sadb_sa_state = x->km.dying ?
			SADB_SASTATE_DYING : SADB_SASTATE_MATURE;
		break;
	case XFRM_STATE_ACQ:
		sa->sadb_sa_state = SADB_SASTATE_LARVAL;
		break;
	default:
		sa->sadb_sa_state = SADB_SASTATE_DEAD;
		break;
	}
	sa->sadb_sa_auth = 0;
	if (x->aalg) {
		struct xfrm_algo_desc *a = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
		sa->sadb_sa_auth = (a && a->pfkey_supported) ?
					a->desc.sadb_alg_id : 0;
	}
	sa->sadb_sa_encrypt = 0;
	BUG_ON(x->ealg && x->calg);
	if (x->ealg) {
		struct xfrm_algo_desc *a = xfrm_ealg_get_byname(x->ealg->alg_name, 0);
		sa->sadb_sa_encrypt = (a && a->pfkey_supported) ?
					a->desc.sadb_alg_id : 0;
	}
	/* KAME compatible: sadb_sa_encrypt is overloaded with calg id */
	if (x->calg) {
		struct xfrm_algo_desc *a = xfrm_calg_get_byname(x->calg->alg_name, 0);
		sa->sadb_sa_encrypt = (a && a->pfkey_supported) ?
					a->desc.sadb_alg_id : 0;
	}

	sa->sadb_sa_flags = 0;
	if (x->props.flags & XFRM_STATE_NOECN)
		sa->sadb_sa_flags |= SADB_SAFLAGS_NOECN;
	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
		sa->sadb_sa_flags |= SADB_SAFLAGS_DECAP_DSCP;
	if (x->props.flags & XFRM_STATE_NOPMTUDISC)
		sa->sadb_sa_flags |= SADB_SAFLAGS_NOPMTUDISC;

	/* hard time */
	if (hsc & 2) {
		lifetime = (struct sadb_lifetime *)  skb_put(skb,
							     sizeof(struct sadb_lifetime));
		lifetime->sadb_lifetime_len =
			sizeof(struct sadb_lifetime)/sizeof(uint64_t);
		lifetime->sadb_lifetime_exttype = SADB_EXT_LIFETIME_HARD;
		lifetime->sadb_lifetime_allocations =  _X2KEY(x->lft.hard_packet_limit);
		lifetime->sadb_lifetime_bytes = _X2KEY(x->lft.hard_byte_limit);
		lifetime->sadb_lifetime_addtime = x->lft.hard_add_expires_seconds;
		lifetime->sadb_lifetime_usetime = x->lft.hard_use_expires_seconds;
	}
	/* soft time */
	if (hsc & 1) {
		lifetime = (struct sadb_lifetime *)  skb_put(skb,
							     sizeof(struct sadb_lifetime));
		lifetime->sadb_lifetime_len =
			sizeof(struct sadb_lifetime)/sizeof(uint64_t);
		lifetime->sadb_lifetime_exttype = SADB_EXT_LIFETIME_SOFT;
		lifetime->sadb_lifetime_allocations =  _X2KEY(x->lft.soft_packet_limit);
		lifetime->sadb_lifetime_bytes = _X2KEY(x->lft.soft_byte_limit);
		lifetime->sadb_lifetime_addtime = x->lft.soft_add_expires_seconds;
		lifetime->sadb_lifetime_usetime = x->lft.soft_use_expires_seconds;
	}
	/* current time */
	lifetime = (struct sadb_lifetime *)  skb_put(skb,
						     sizeof(struct sadb_lifetime));
	lifetime->sadb_lifetime_len =
		sizeof(struct sadb_lifetime)/sizeof(uint64_t);
	lifetime->sadb_lifetime_exttype = SADB_EXT_LIFETIME_CURRENT;
	lifetime->sadb_lifetime_allocations = x->curlft.packets;
	lifetime->sadb_lifetime_bytes = x->curlft.bytes;
	lifetime->sadb_lifetime_addtime = x->curlft.add_time;
	lifetime->sadb_lifetime_usetime = x->curlft.use_time;
	/* src address */
	addr = (struct sadb_address*) skb_put(skb,
					      sizeof(struct sadb_address)+sockaddr_size);
	addr->sadb_address_len =
		(sizeof(struct sadb_address)+sockaddr_size)/
			sizeof(uint64_t);
	addr->sadb_address_exttype = SADB_EXT_ADDRESS_SRC;
	/* "if the ports are non-zero, then the sadb_address_proto field,
	   normally zero, MUST be filled in with the transport
	   protocol's number." - RFC2367 */
	addr->sadb_address_proto = 0;
	addr->sadb_address_reserved = 0;

	addr->sadb_address_prefixlen =
		pfkey_sockaddr_fill(&x->props.saddr, 0,
				    (struct sockaddr *) (addr + 1),
				    x->props.family);
	if (!addr->sadb_address_prefixlen)
		BUG();

	/* dst address */
	addr = (struct sadb_address*) skb_put(skb,
					      sizeof(struct sadb_address)+sockaddr_size);
	addr->sadb_address_len =
		(sizeof(struct sadb_address)+sockaddr_size)/
			sizeof(uint64_t);
	addr->sadb_address_exttype = SADB_EXT_ADDRESS_DST;
	addr->sadb_address_proto = 0;
	addr->sadb_address_reserved = 0;

	addr->sadb_address_prefixlen =
		pfkey_sockaddr_fill(&x->id.daddr, 0,
				    (struct sockaddr *) (addr + 1),
				    x->props.family);
	if (!addr->sadb_address_prefixlen)
		BUG();

	if (!xfrm_addr_equal(&x->sel.saddr, &x->props.saddr,
			     x->props.family)) {
		addr = (struct sadb_address*) skb_put(skb,
			sizeof(struct sadb_address)+sockaddr_size);
		addr->sadb_address_len =
			(sizeof(struct sadb_address)+sockaddr_size)/
			sizeof(uint64_t);
		addr->sadb_address_exttype = SADB_EXT_ADDRESS_PROXY;
		addr->sadb_address_proto =
			pfkey_proto_from_xfrm(x->sel.proto);
		addr->sadb_address_prefixlen = x->sel.prefixlen_s;
		addr->sadb_address_reserved = 0;

		pfkey_sockaddr_fill(&x->sel.saddr, x->sel.sport,
				    (struct sockaddr *) (addr + 1),
				    x->props.family);
	}

	/* auth key */
	if (add_keys && auth_key_size) {
		key = (struct sadb_key *) skb_put(skb,
						  sizeof(struct sadb_key)+auth_key_size);
		key->sadb_key_len = (sizeof(struct sadb_key) + auth_key_size) /
			sizeof(uint64_t);
		key->sadb_key_exttype = SADB_EXT_KEY_AUTH;
		key->sadb_key_bits = x->aalg->alg_key_len;
		key->sadb_key_reserved = 0;
		memcpy(key + 1, x->aalg->alg_key, (x->aalg->alg_key_len+7)/8);
	}
	/* encrypt key */
	if (add_keys && encrypt_key_size) {
		key = (struct sadb_key *) skb_put(skb,
						  sizeof(struct sadb_key)+encrypt_key_size);
		key->sadb_key_len = (sizeof(struct sadb_key) +
				     encrypt_key_size) / sizeof(uint64_t);
		key->sadb_key_exttype = SADB_EXT_KEY_ENCRYPT;
		key->sadb_key_bits = x->ealg->alg_key_len;
		key->sadb_key_reserved = 0;
		memcpy(key + 1, x->ealg->alg_key,
		       (x->ealg->alg_key_len+7)/8);
	}

	/* sa */
	sa2 = (struct sadb_x_sa2 *)  skb_put(skb, sizeof(struct sadb_x_sa2));
	sa2->sadb_x_sa2_len = sizeof(struct sadb_x_sa2)/sizeof(uint64_t);
	sa2->sadb_x_sa2_exttype = SADB_X_EXT_SA2;
	if ((mode = pfkey_mode_from_xfrm(x->props.mode)) < 0) {
		kfree_skb(skb);
		return ERR_PTR(-EINVAL);
	}
	sa2->sadb_x_sa2_mode = mode;
	sa2->sadb_x_sa2_reserved1 = 0;
	sa2->sadb_x_sa2_reserved2 = 0;
	sa2->sadb_x_sa2_sequence = 0;
	sa2->sadb_x_sa2_reqid = x->props.reqid;

	if (natt && natt->encap_type) {
		struct sadb_x_nat_t_type *n_type;
		struct sadb_x_nat_t_port *n_port;

		/* type */
		n_type = (struct sadb_x_nat_t_type*) skb_put(skb, sizeof(*n_type));
		n_type->sadb_x_nat_t_type_len = sizeof(*n_type)/sizeof(uint64_t);
		n_type->sadb_x_nat_t_type_exttype = SADB_X_EXT_NAT_T_TYPE;
		n_type->sadb_x_nat_t_type_type = natt->encap_type;
		n_type->sadb_x_nat_t_type_reserved[0] = 0;
		n_type->sadb_x_nat_t_type_reserved[1] = 0;
		n_type->sadb_x_nat_t_type_reserved[2] = 0;

		/* source port */
		n_port = (struct sadb_x_nat_t_port*) skb_put(skb, sizeof (*n_port));
		n_port->sadb_x_nat_t_port_len = sizeof(*n_port)/sizeof(uint64_t);
		n_port->sadb_x_nat_t_port_exttype = SADB_X_EXT_NAT_T_SPORT;
		n_port->sadb_x_nat_t_port_port = natt->encap_sport;
		n_port->sadb_x_nat_t_port_reserved = 0;

		/* dest port */
		n_port = (struct sadb_x_nat_t_port*) skb_put(skb, sizeof (*n_port));
		n_port->sadb_x_nat_t_port_len = sizeof(*n_port)/sizeof(uint64_t);
		n_port->sadb_x_nat_t_port_exttype = SADB_X_EXT_NAT_T_DPORT;
		n_port->sadb_x_nat_t_port_port = natt->encap_dport;
		n_port->sadb_x_nat_t_port_reserved = 0;
	}

	/* security context */
	if (xfrm_ctx) {
		sec_ctx = (struct sadb_x_sec_ctx *) skb_put(skb,
				sizeof(struct sadb_x_sec_ctx) + ctx_size);
		sec_ctx->sadb_x_sec_len =
		  (sizeof(struct sadb_x_sec_ctx) + ctx_size) / sizeof(uint64_t);
		sec_ctx->sadb_x_sec_exttype = SADB_X_EXT_SEC_CTX;
		sec_ctx->sadb_x_ctx_doi = xfrm_ctx->ctx_doi;
		sec_ctx->sadb_x_ctx_alg = xfrm_ctx->ctx_alg;
		sec_ctx->sadb_x_ctx_len = xfrm_ctx->ctx_len;
		memcpy(sec_ctx + 1, xfrm_ctx->ctx_str,
		       xfrm_ctx->ctx_len);
	}

	return skb;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.