net/ipv6/xfrm6_input.c - linux - Git at Google

 // 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 ret;

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

 	offset = offset - sizeof(struct udphdr);

 	if (!pskb_pull(skb, offset))
 		return NULL;

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

 	ret = __xfrm6_udp_encap_rcv(sk, skb, false);
 	if (ret)
 		goto out;

 	skb_push(skb, offset);
 	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();
 	skb_push(skb, offset);
 	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);
	// 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 ret;

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

	offset = offset - sizeof(struct udphdr);

	if (!pskb_pull(skb, offset))
	return NULL;

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

	ret = __xfrm6_udp_encap_rcv(sk, skb, false);
	if (ret)
	goto out;

	skb_push(skb, offset);
	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();
	skb_push(skb, offset);
	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);