[linux-block.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>

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->data - skb_network_header(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)) {
		skb_mac_header_rebuild(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;
}

/* 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)
{
	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 = 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) {
			goto drop;
		} 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;
	case UDP_ENCAP_ESPINUDP_NON_IKE:
		/* Check if this is a keepalive packet.  If so, eat it. */
		if (len == 1 && udpdata[0] == 0xff) {
			goto drop;
		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
			   udpdata32[0] == 0 && udpdata32[1] == 0) {

			/* ESP Packet with Non-IKE marker */
			len = sizeof(struct udphdr) + 2 * sizeof(u32);
		} 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))
		goto drop;

	/* 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!?! */
		goto drop;
	}

	/* 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.
	 */
	__skb_pull(skb, len);
	skb_reset_transport_header(skb);

	/* process ESP */
	return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);

drop:
	kfree_skb(skb);
	return 0;
}

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;

		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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* xfrm6_input.c: based on net/ipv4/xfrm4_input.c
	4	*
	5	* Authors:
	6	* Mitsuru KANDA @USAGI
67ba4152 IM	7	* Kazunori MIYAZAWA @USAGI
67ba4152 IM	8	* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
1da177e4 LT	9	* YOSHIFUJI Hideaki @USAGI
	10	* IPv6 support
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/string.h>
b05e1066 PM	15	#include <linux/netfilter.h>
b05e1066 PM	16	#include <linux/netfilter_ipv6.h>
1da177e4 LT	17	#include <net/ipv6.h>
	18	#include <net/xfrm.h>
	19
63c43787 ND	20	int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi,
63c43787 ND	21	struct ip6_tnl *t)
1da177e4	22	{
63c43787	23	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
2fcb45b6	24	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
716062fd HX	25	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
	26	return xfrm_input(skb, nexthdr, spi, 0);
	27	}
	28	EXPORT_SYMBOL(xfrm6_rcv_spi);
b05e1066	29
acf568ee HX	30	static int xfrm6_transport_finish2(struct net net, struct sock sk,
	31	struct sk_buff *skb)
	32	{
0146dca7 SD	33	if (xfrm_trans_queue(skb, ip6_rcv_finish)) {
	34	kfree_skb(skb);
	35	return NET_RX_DROP;
	36	}
	37
	38	return 0;
acf568ee HX	39	}
acf568ee HX	40
716062fd HX	41	int xfrm6_transport_finish(struct sk_buff *skb, int async)
716062fd HX	42	{
7785bba2	43	struct xfrm_offload *xo = xfrm_offload(skb);
e9cba694	44	int nhlen = skb->data - skb_network_header(skb);
7785bba2	45
60d5fcfb HX	46	skb_network_header(skb)[IP6CB(skb)->nhoff] =
	47	XFRM_MODE_SKB_CB(skb)->protocol;
	48
0883ae0e HX	49	#ifndef CONFIG_NETFILTER
	50	if (!async)
	51	return 1;
	52	#endif
	53
e9cba694	54	__skb_push(skb, nhlen);
7c88e21a	55	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
e9cba694	56	skb_postpush_rcsum(skb, skb_network_header(skb), nhlen);
b05e1066	57
7785bba2 SK	58	if (xo && (xo->flags & XFRM_GRO)) {
7785bba2 SK	59	skb_mac_header_rebuild(skb);
bfc0698b	60	skb_reset_transport_header(skb);
0146dca7	61	return 0;
7785bba2 SK	62	}
7785bba2 SK	63
29a26a56 EB	64	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
29a26a56 EB	65	dev_net(skb->dev), NULL, skb, skb->dev, NULL,
acf568ee	66	xfrm6_transport_finish2);
0146dca7 SD	67	return 0;
	68	}
	69
	70	/* If it's a keepalive packet, then just eat it.
	71	* If it's an encapsulated packet, then pass it to the
	72	* IPsec xfrm input.
	73	* Returns 0 if skb passed to xfrm or was dropped.
	74	* Returns >0 if skb should be passed to UDP.
	75	* Returns <0 if skb should be resubmitted (-ret is protocol)
	76	*/
	77	int xfrm6_udp_encap_rcv(struct sock sk, struct sk_buff skb)
	78	{
	79	struct udp_sock *up = udp_sk(sk);
	80	struct udphdr *uh;
	81	struct ipv6hdr *ip6h;
	82	int len;
	83	int ip6hlen = sizeof(struct ipv6hdr);
	84
	85	__u8 *udpdata;
	86	__be32 *udpdata32;
	87	__u16 encap_type = up->encap_type;
	88
	89	/* if this is not encapsulated socket, then just return now */
	90	if (!encap_type)
	91	return 1;
	92
	93	/* If this is a paged skb, make sure we pull up
	94	* whatever data we need to look at. */
	95	len = skb->len - sizeof(struct udphdr);
	96	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
	97	return 1;
	98
	99	/* Now we can get the pointers */
	100	uh = udp_hdr(skb);
	101	udpdata = (__u8 *)uh + sizeof(struct udphdr);
	102	udpdata32 = (__be32 *)udpdata;
	103
	104	switch (encap_type) {
	105	default:
	106	case UDP_ENCAP_ESPINUDP:
	107	/* Check if this is a keepalive packet. If so, eat it. */
	108	if (len == 1 && udpdata[0] == 0xff) {
	109	goto drop;
	110	} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
	111	/* ESP Packet without Non-ESP header */
	112	len = sizeof(struct udphdr);
	113	} else
	114	/* Must be an IKE packet.. pass it through */
	115	return 1;
	116	break;
	117	case UDP_ENCAP_ESPINUDP_NON_IKE:
	118	/* Check if this is a keepalive packet. If so, eat it. */
	119	if (len == 1 && udpdata[0] == 0xff) {
	120	goto drop;
	121	} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
	122	udpdata32[0] == 0 && udpdata32[1] == 0) {
	123
	124	/* ESP Packet with Non-IKE marker */
	125	len = sizeof(struct udphdr) + 2 * sizeof(u32);
	126	} else
	127	/* Must be an IKE packet.. pass it through */
	128	return 1;
	129	break;
	130	}
131
132	/* At this point we are sure that this is an ESPinUDP packet,
133	* so we need to remove 'len' bytes from the packet (the UDP
134	* header and optional ESP marker bytes) and then modify the
135	* protocol to ESP, and then call into the transform receiver.
136	*/
137	if (skb_unclone(skb, GFP_ATOMIC))
138	goto drop;
139
140	/* Now we can update and verify the packet length... */
141	ip6h = ipv6_hdr(skb);
142	ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len);
143	if (skb->len < ip6hlen + len) {
144	/* packet is too small!?! */
145	goto drop;
146	}
147
148	/* pull the data buffer up to the ESP header and set the
149	* transport header to point to ESP. Keep UDP on the stack
150	* for later.
151	*/
152	__skb_pull(skb, len);
153	skb_reset_transport_header(skb);
154
155	/* process ESP */
156	return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
157
158	drop:
159	kfree_skb(skb);
160	return 0;
1da177e4 LT	161	}
1da177e4 LT	162
63c43787	163	int xfrm6_rcv_tnl(struct sk_buff skb, struct ip6_tnl t)
1da177e4	164	{
33b5ecb8	165	return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
63c43787	166	0, t);
1da177e4	167	}
63c43787	168	EXPORT_SYMBOL(xfrm6_rcv_tnl);
7159039a	169
63c43787 ND	170	int xfrm6_rcv(struct sk_buff *skb)
	171	{
	172	return xfrm6_rcv_tnl(skb, NULL);
	173	}
	174	EXPORT_SYMBOL(xfrm6_rcv);
fbd9a5b4 MN	175	int xfrm6_input_addr(struct sk_buff skb, xfrm_address_t daddr,
	176	xfrm_address_t *saddr, u8 proto)
	177	{
59c9940e	178	struct net *net = dev_net(skb->dev);
1ab1457c	179	struct xfrm_state *x = NULL;
0ca64da1	180	struct sec_path *sp;
fbd9a5b4 MN	181	int i = 0;
fbd9a5b4 MN	182
0ca64da1 FW	183	sp = secpath_set(skb);
0ca64da1 FW	184	if (!sp) {
b0fcee82 SK	185	XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
b0fcee82 SK	186	goto drop;
9473e1f6 MN	187	}
9473e1f6 MN	188
0ca64da1	189	if (1 + sp->len == XFRM_MAX_DEPTH) {
59c9940e	190	XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
9473e1f6 MN	191	goto drop;
	192	}
	193
fbd9a5b4 MN	194	for (i = 0; i < 3; i++) {
fbd9a5b4 MN	195	xfrm_address_t dst, src;
a002c6fd	196
fbd9a5b4 MN	197	switch (i) {
	198	case 0:
	199	dst = daddr;
	200	src = saddr;
	201	break;
	202	case 1:
	203	/* lookup state with wild-card source address */
fbd9a5b4	204	dst = daddr;
a002c6fd	205	src = (xfrm_address_t *)&in6addr_any;
fbd9a5b4	206	break;
fbd9a5b4	207	default:
1ab1457c	208	/* lookup state with wild-card addresses */
a002c6fd YH	209	dst = (xfrm_address_t *)&in6addr_any;
a002c6fd YH	210	src = (xfrm_address_t *)&in6addr_any;
fbd9a5b4	211	break;
1ab1457c	212	}
fbd9a5b4	213
bd55775c	214	x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
fbd9a5b4 MN	215	if (!x)
	216	continue;
	217
	218	spin_lock(&x->lock);
	219
a002c6fd YH	220	if ((!i \|\| (x->props.flags & XFRM_STATE_WILDRECV)) &&
	221	likely(x->km.state == XFRM_STATE_VALID) &&
	222	!xfrm_state_check_expire(x)) {
fbd9a5b4	223	spin_unlock(&x->lock);
a002c6fd YH	224	if (x->type->input(x, skb) > 0) {
	225	/* found a valid state */
	226	break;
	227	}
	228	} else
fbd9a5b4	229	spin_unlock(&x->lock);
fbd9a5b4	230
a002c6fd YH	231	xfrm_state_put(x);
a002c6fd YH	232	x = NULL;
fbd9a5b4 MN	233	}
fbd9a5b4 MN	234
9473e1f6	235	if (!x) {
59c9940e	236	XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
afeb14b4	237	xfrm_audit_state_notfound_simple(skb, AF_INET6);
fbd9a5b4	238	goto drop;
fbd9a5b4 MN	239	}
fbd9a5b4 MN	240
2294be0f	241	sp->xvec[sp->len++] = x;
9473e1f6 MN	242
9473e1f6 MN	243	spin_lock(&x->lock);
fbd9a5b4	244
9473e1f6 MN	245	x->curlft.bytes += skb->len;
	246	x->curlft.packets++;
	247
	248	spin_unlock(&x->lock);
fbd9a5b4 MN	249
fbd9a5b4 MN	250	return 1;
9473e1f6	251
fbd9a5b4	252	drop:
fbd9a5b4 MN	253	return -1;
fbd9a5b4 MN	254	}
7159039a	255	EXPORT_SYMBOL(xfrm6_input_addr);