[thirdparty/kernel/linux.git] / net / ipv6 / xfrm6_input.c

// SPDX-License-Identifier: GPL-2.0
/*
 * xfrm6_input.c: based on net/ipv4/xfrm4_input.c
 *
 * Authors:
 *	Mitsuru KANDA @USAGI
 *	Kazunori MIYAZAWA @USAGI
 *	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
 *	YOSHIFUJI Hideaki @USAGI
 *		IPv6 support
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <net/ipv6.h>
#include <net/xfrm.h>
#include <net/protocol.h>
#include <net/gro.h>

int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi,
		  struct ip6_tnl *t)
{
	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
	return xfrm_input(skb, nexthdr, spi, 0);
}
EXPORT_SYMBOL(xfrm6_rcv_spi);

static int xfrm6_transport_finish2(struct net *net, struct sock *sk,
				   struct sk_buff *skb)
{
	if (xfrm_trans_queue(skb, ip6_rcv_finish)) {
		kfree_skb(skb);
		return NET_RX_DROP;
	}

	return 0;
}

int xfrm6_transport_finish(struct sk_buff *skb, int async)
{
	struct xfrm_offload *xo = xfrm_offload(skb);
	int nhlen = -skb_network_offset(skb);

	skb_network_header(skb)[IP6CB(skb)->nhoff] =
		XFRM_MODE_SKB_CB(skb)->protocol;

#ifndef CONFIG_NETFILTER
	if (!async)
		return 1;
#endif

	__skb_push(skb, nhlen);
	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	skb_postpush_rcsum(skb, skb_network_header(skb), nhlen);

	if (xo && (xo->flags & XFRM_GRO)) {
		/* The full l2 header needs to be preserved so that re-injecting the packet at l2
		 * works correctly in the presence of vlan tags.
		 */
		skb_mac_header_rebuild_full(skb, xo->orig_mac_len);
		skb_reset_network_header(skb);
		skb_reset_transport_header(skb);
		return 0;
	}

	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
		xfrm6_transport_finish2);
	return 0;
}

static int __xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
{
	struct udp_sock *up = udp_sk(sk);
	struct udphdr *uh;
	struct ipv6hdr *ip6h;
	int len;
	int ip6hlen = sizeof(struct ipv6hdr);
	__u8 *udpdata;
	__be32 *udpdata32;
	u16 encap_type;

	encap_type = READ_ONCE(up->encap_type);
	/* if this is not encapsulated socket, then just return now */
	if (!encap_type)
		return 1;

	/* If this is a paged skb, make sure we pull up
	 * whatever data we need to look at. */
	len = skb->len - sizeof(struct udphdr);
	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
		return 1;

	/* Now we can get the pointers */
	uh = udp_hdr(skb);
	udpdata = (__u8 *)uh + sizeof(struct udphdr);
	udpdata32 = (__be32 *)udpdata;

	switch (encap_type) {
	default:
	case UDP_ENCAP_ESPINUDP:
		/* Check if this is a keepalive packet.  If so, eat it. */
		if (len == 1 && udpdata[0] == 0xff) {
			return -EINVAL;
		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
			/* ESP Packet without Non-ESP header */
			len = sizeof(struct udphdr);
		} else
			/* Must be an IKE packet.. pass it through */
			return 1;
		break;
	}

	/* At this point we are sure that this is an ESPinUDP packet,
	 * so we need to remove 'len' bytes from the packet (the UDP
	 * header and optional ESP marker bytes) and then modify the
	 * protocol to ESP, and then call into the transform receiver.
	 */
	if (skb_unclone(skb, GFP_ATOMIC))
		return -EINVAL;

	/* Now we can update and verify the packet length... */
	ip6h = ipv6_hdr(skb);
	ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len);
	if (skb->len < ip6hlen + len) {
		/* packet is too small!?! */
		return -EINVAL;
	}

	/* pull the data buffer up to the ESP header and set the
	 * transport header to point to ESP.  Keep UDP on the stack
	 * for later.
	 */
	if (pull) {
		__skb_pull(skb, len);
		skb_reset_transport_header(skb);
	} else {
		skb_set_transport_header(skb, len);
	}

	/* process ESP */
	return 0;
}

/* If it's a keepalive packet, then just eat it.
 * If it's an encapsulated packet, then pass it to the
 * IPsec xfrm input.
 * Returns 0 if skb passed to xfrm or was dropped.
 * Returns >0 if skb should be passed to UDP.
 * Returns <0 if skb should be resubmitted (-ret is protocol)
 */
int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
{
	int ret;

	if (skb->protocol == htons(ETH_P_IP))
		return xfrm4_udp_encap_rcv(sk, skb);

	ret = __xfrm6_udp_encap_rcv(sk, skb, true);
	if (!ret)
		return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0,
				       udp_sk(sk)->encap_type);

	if (ret < 0) {
		kfree_skb(skb);
		return 0;
	}

	return ret;
}

struct sk_buff *xfrm6_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
					struct sk_buff *skb)
{
	int offset = skb_gro_offset(skb);
	const struct net_offload *ops;
	struct sk_buff *pp = NULL;
	int len, dlen;
	__u8 *udpdata;
	__be32 *udpdata32;

	if (skb->protocol == htons(ETH_P_IP))
		return xfrm4_gro_udp_encap_rcv(sk, head, skb);

	len = skb->len - offset;
	dlen = offset + min(len, 8);
	udpdata = skb_gro_header(skb, dlen, offset);
	udpdata32 = (__be32 *)udpdata;
	if (unlikely(!udpdata))
		return NULL;

	rcu_read_lock();
	ops = rcu_dereference(inet6_offloads[IPPROTO_ESP]);
	if (!ops || !ops->callbacks.gro_receive)
		goto out;

	/* check if it is a keepalive or IKE packet */
	if (len <= sizeof(struct ip_esp_hdr) || udpdata32[0] == 0)
		goto out;

	NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;

	pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
	rcu_read_unlock();

	return pp;

out:
	rcu_read_unlock();
	NAPI_GRO_CB(skb)->same_flow = 0;
	NAPI_GRO_CB(skb)->flush = 1;

	return NULL;
}

int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t)
{
	return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
			     0, t);
}
EXPORT_SYMBOL(xfrm6_rcv_tnl);

int xfrm6_rcv(struct sk_buff *skb)
{
	return xfrm6_rcv_tnl(skb, NULL);
}
EXPORT_SYMBOL(xfrm6_rcv);
int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
		     xfrm_address_t *saddr, u8 proto)
{
	struct net *net = dev_net(skb->dev);
	struct xfrm_state *x = NULL;
	struct sec_path *sp;
	int i = 0;

	sp = secpath_set(skb);
	if (!sp) {
		XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
		goto drop;
	}

	if (1 + sp->len == XFRM_MAX_DEPTH) {
		XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
		goto drop;
	}

	for (i = 0; i < 3; i++) {
		xfrm_address_t *dst, *src;

		switch (i) {
		case 0:
			dst = daddr;
			src = saddr;
			break;
		case 1:
			/* lookup state with wild-card source address */
			dst = daddr;
			src = (xfrm_address_t *)&in6addr_any;
			break;
		default:
			/* lookup state with wild-card addresses */
			dst = (xfrm_address_t *)&in6addr_any;
			src = (xfrm_address_t *)&in6addr_any;
			break;
		}

		x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
		if (!x)
			continue;

		if (unlikely(x->dir && x->dir != XFRM_SA_DIR_IN)) {
			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEDIRERROR);
			xfrm_state_put(x);
			x = NULL;
			continue;
		}

		spin_lock(&x->lock);

		if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
		    likely(x->km.state == XFRM_STATE_VALID) &&
		    !xfrm_state_check_expire(x)) {
			spin_unlock(&x->lock);
			if (x->type->input(x, skb) > 0) {
				/* found a valid state */
				break;
			}
		} else
			spin_unlock(&x->lock);

		xfrm_state_put(x);
		x = NULL;
	}

	if (!x) {
		XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
		xfrm_audit_state_notfound_simple(skb, AF_INET6);
		goto drop;
	}

	sp->xvec[sp->len++] = x;

	spin_lock(&x->lock);

	x->curlft.bytes += skb->len;
	x->curlft.packets++;

	spin_unlock(&x->lock);

	return 1;

drop:
	return -1;
}
EXPORT_SYMBOL(xfrm6_input_addr);
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* xfrm6_input.c: based on net/ipv4/xfrm4_input.c
	4	*
	5	* Authors:
	6	* Mitsuru KANDA @USAGI
	7	* Kazunori MIYAZAWA @USAGI
	8	* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
	9	* YOSHIFUJI Hideaki @USAGI
	10	* IPv6 support
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/string.h>
	15	#include <linux/netfilter.h>
	16	#include <linux/netfilter_ipv6.h>
	17	#include <net/ipv6.h>
	18	#include <net/xfrm.h>
	19	#include <net/protocol.h>
	20	#include <net/gro.h>
	21
	22	int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi,
	23	struct ip6_tnl *t)
	24	{
	25	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
	26	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
	27	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
	28	return xfrm_input(skb, nexthdr, spi, 0);
	29	}
	30	EXPORT_SYMBOL(xfrm6_rcv_spi);
	31
	32	static int xfrm6_transport_finish2(struct net net, struct sock sk,
	33	struct sk_buff *skb)
	34	{
	35	if (xfrm_trans_queue(skb, ip6_rcv_finish)) {
	36	kfree_skb(skb);
	37	return NET_RX_DROP;
	38	}
	39
	40	return 0;
	41	}
	42
	43	int xfrm6_transport_finish(struct sk_buff *skb, int async)
	44	{
	45	struct xfrm_offload *xo = xfrm_offload(skb);
	46	int nhlen = -skb_network_offset(skb);
	47
	48	skb_network_header(skb)[IP6CB(skb)->nhoff] =
	49	XFRM_MODE_SKB_CB(skb)->protocol;
	50
	51	#ifndef CONFIG_NETFILTER
	52	if (!async)
	53	return 1;
	54	#endif
	55
	56	__skb_push(skb, nhlen);
	57	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	58	skb_postpush_rcsum(skb, skb_network_header(skb), nhlen);
	59
	60	if (xo && (xo->flags & XFRM_GRO)) {
	61	/* The full l2 header needs to be preserved so that re-injecting the packet at l2
	62	* works correctly in the presence of vlan tags.
	63	*/
	64	skb_mac_header_rebuild_full(skb, xo->orig_mac_len);
	65	skb_reset_network_header(skb);
	66	skb_reset_transport_header(skb);
	67	return 0;
	68	}
	69
	70	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
	71	dev_net(skb->dev), NULL, skb, skb->dev, NULL,
	72	xfrm6_transport_finish2);
	73	return 0;
	74	}
	75
	76	static int __xfrm6_udp_encap_rcv(struct sock sk, struct sk_buff skb, bool pull)
	77	{
	78	struct udp_sock *up = udp_sk(sk);
	79	struct udphdr *uh;
	80	struct ipv6hdr *ip6h;
	81	int len;
	82	int ip6hlen = sizeof(struct ipv6hdr);
	83	__u8 *udpdata;
	84	__be32 *udpdata32;
	85	u16 encap_type;
	86
	87	encap_type = READ_ONCE(up->encap_type);
	88	/* if this is not encapsulated socket, then just return now */
	89	if (!encap_type)
	90	return 1;
	91
	92	/* If this is a paged skb, make sure we pull up
	93	* whatever data we need to look at. */
	94	len = skb->len - sizeof(struct udphdr);
	95	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
	96	return 1;
	97
	98	/* Now we can get the pointers */
	99	uh = udp_hdr(skb);
	100	udpdata = (__u8 *)uh + sizeof(struct udphdr);
	101	udpdata32 = (__be32 *)udpdata;
	102
	103	switch (encap_type) {
	104	default:
	105	case UDP_ENCAP_ESPINUDP:
	106	/* Check if this is a keepalive packet. If so, eat it. */
	107	if (len == 1 && udpdata[0] == 0xff) {
	108	return -EINVAL;
	109	} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
	110	/* ESP Packet without Non-ESP header */
	111	len = sizeof(struct udphdr);
	112	} else
	113	/* Must be an IKE packet.. pass it through */
	114	return 1;
	115	break;
	116	}
	117
	118	/* At this point we are sure that this is an ESPinUDP packet,
	119	* so we need to remove 'len' bytes from the packet (the UDP
	120	* header and optional ESP marker bytes) and then modify the
	121	* protocol to ESP, and then call into the transform receiver.
	122	*/
	123	if (skb_unclone(skb, GFP_ATOMIC))
	124	return -EINVAL;
	125
	126	/* Now we can update and verify the packet length... */
	127	ip6h = ipv6_hdr(skb);
	128	ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len);
	129	if (skb->len < ip6hlen + len) {
	130	/* packet is too small!?! */
	131	return -EINVAL;
	132	}
	133
	134	/* pull the data buffer up to the ESP header and set the
	135	* transport header to point to ESP. Keep UDP on the stack
	136	* for later.
	137	*/
	138	if (pull) {
	139	__skb_pull(skb, len);
	140	skb_reset_transport_header(skb);
	141	} else {
	142	skb_set_transport_header(skb, len);
	143	}
	144
	145	/* process ESP */
	146	return 0;
	147	}
	148
	149	/* If it's a keepalive packet, then just eat it.
	150	* If it's an encapsulated packet, then pass it to the
	151	* IPsec xfrm input.
	152	* Returns 0 if skb passed to xfrm or was dropped.
	153	* Returns >0 if skb should be passed to UDP.
	154	* Returns <0 if skb should be resubmitted (-ret is protocol)
	155	*/
	156	int xfrm6_udp_encap_rcv(struct sock sk, struct sk_buff skb)
	157	{
	158	int ret;
	159
	160	if (skb->protocol == htons(ETH_P_IP))
	161	return xfrm4_udp_encap_rcv(sk, skb);
	162
	163	ret = __xfrm6_udp_encap_rcv(sk, skb, true);
	164	if (!ret)
	165	return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0,
	166	udp_sk(sk)->encap_type);
	167
	168	if (ret < 0) {
	169	kfree_skb(skb);
	170	return 0;
	171	}
	172
	173	return ret;
	174	}
	175
	176	struct sk_buff xfrm6_gro_udp_encap_rcv(struct sock sk, struct list_head *head,
	177	struct sk_buff *skb)
	178	{
	179	int offset = skb_gro_offset(skb);
	180	const struct net_offload *ops;
	181	struct sk_buff *pp = NULL;
	182	int len, dlen;
	183	__u8 *udpdata;
	184	__be32 *udpdata32;
	185
	186	if (skb->protocol == htons(ETH_P_IP))
	187	return xfrm4_gro_udp_encap_rcv(sk, head, skb);
	188
	189	len = skb->len - offset;
	190	dlen = offset + min(len, 8);
	191	udpdata = skb_gro_header(skb, dlen, offset);
	192	udpdata32 = (__be32 *)udpdata;
	193	if (unlikely(!udpdata))
	194	return NULL;
	195
	196	rcu_read_lock();
	197	ops = rcu_dereference(inet6_offloads[IPPROTO_ESP]);
	198	if (!ops \|\| !ops->callbacks.gro_receive)
	199	goto out;
	200
	201	/* check if it is a keepalive or IKE packet */
	202	if (len <= sizeof(struct ip_esp_hdr) \|\| udpdata32[0] == 0)
	203	goto out;
	204
	205	NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
	206
	207	pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
	208	rcu_read_unlock();
	209
	210	return pp;
	211
	212	out:
	213	rcu_read_unlock();
	214	NAPI_GRO_CB(skb)->same_flow = 0;
	215	NAPI_GRO_CB(skb)->flush = 1;
	216
	217	return NULL;
	218	}
	219
	220	int xfrm6_rcv_tnl(struct sk_buff skb, struct ip6_tnl t)
	221	{
	222	return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
	223	0, t);
	224	}
	225	EXPORT_SYMBOL(xfrm6_rcv_tnl);
	226
	227	int xfrm6_rcv(struct sk_buff *skb)
	228	{
	229	return xfrm6_rcv_tnl(skb, NULL);
	230	}
	231	EXPORT_SYMBOL(xfrm6_rcv);
	232	int xfrm6_input_addr(struct sk_buff skb, xfrm_address_t daddr,
	233	xfrm_address_t *saddr, u8 proto)
	234	{
	235	struct net *net = dev_net(skb->dev);
	236	struct xfrm_state *x = NULL;
	237	struct sec_path *sp;
	238	int i = 0;
	239
	240	sp = secpath_set(skb);
	241	if (!sp) {
	242	XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
	243	goto drop;
	244	}
	245
	246	if (1 + sp->len == XFRM_MAX_DEPTH) {
	247	XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
	248	goto drop;
	249	}
	250
	251	for (i = 0; i < 3; i++) {
	252	xfrm_address_t dst, src;
	253
	254	switch (i) {
	255	case 0:
	256	dst = daddr;
	257	src = saddr;
	258	break;
	259	case 1:
	260	/* lookup state with wild-card source address */
	261	dst = daddr;
	262	src = (xfrm_address_t *)&in6addr_any;
	263	break;
	264	default:
	265	/* lookup state with wild-card addresses */
	266	dst = (xfrm_address_t *)&in6addr_any;
	267	src = (xfrm_address_t *)&in6addr_any;
	268	break;
	269	}
	270
	271	x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
	272	if (!x)
	273	continue;
	274
	275	if (unlikely(x->dir && x->dir != XFRM_SA_DIR_IN)) {
	276	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEDIRERROR);
	277	xfrm_state_put(x);
	278	x = NULL;
	279	continue;
	280	}
	281
	282	spin_lock(&x->lock);
	283
	284	if ((!i \|\| (x->props.flags & XFRM_STATE_WILDRECV)) &&
	285	likely(x->km.state == XFRM_STATE_VALID) &&
	286	!xfrm_state_check_expire(x)) {
	287	spin_unlock(&x->lock);
	288	if (x->type->input(x, skb) > 0) {
	289	/* found a valid state */
	290	break;
	291	}
	292	} else
	293	spin_unlock(&x->lock);
	294
	295	xfrm_state_put(x);
	296	x = NULL;
	297	}
	298
	299	if (!x) {
	300	XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
	301	xfrm_audit_state_notfound_simple(skb, AF_INET6);
	302	goto drop;
	303	}
	304
	305	sp->xvec[sp->len++] = x;
	306
	307	spin_lock(&x->lock);
	308
	309	x->curlft.bytes += skb->len;
	310	x->curlft.packets++;
	311
	312	spin_unlock(&x->lock);
	313
	314	return 1;
	315
	316	drop:
	317	return -1;
	318	}
	319	EXPORT_SYMBOL(xfrm6_input_addr);