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v3.15
 
  1/*
  2 * xfrm4_input.c
  3 *
  4 * Changes:
  5 *	YOSHIFUJI Hideaki @USAGI
  6 *		Split up af-specific portion
  7 *	Derek Atkins <derek@ihtfp.com>
  8 *		Add Encapsulation support
  9 *
 10 */
 11
 12#include <linux/slab.h>
 13#include <linux/module.h>
 14#include <linux/string.h>
 15#include <linux/netfilter.h>
 16#include <linux/netfilter_ipv4.h>
 17#include <net/ip.h>
 18#include <net/xfrm.h>
 19
 20int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
 21{
 22	return xfrm4_extract_header(skb);
 23}
 24
 25static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
 
 26{
 27	if (skb_dst(skb) == NULL) {
 
 
 
 
 
 
 28		const struct iphdr *iph = ip_hdr(skb);
 29
 30		if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
 31					 iph->tos, skb->dev))
 32			goto drop;
 33	}
 34	return dst_input(skb);
 
 
 
 
 35drop:
 36	kfree_skb(skb);
 37	return NET_RX_DROP;
 38}
 39
 40int xfrm4_transport_finish(struct sk_buff *skb, int async)
 41{
 
 42	struct iphdr *iph = ip_hdr(skb);
 43
 44	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
 45
 46#ifndef CONFIG_NETFILTER
 47	if (!async)
 48		return -iph->protocol;
 49#endif
 50
 51	__skb_push(skb, skb->data - skb_network_header(skb));
 52	iph->tot_len = htons(skb->len);
 53	ip_send_check(iph);
 54
 55	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
 
 
 
 
 
 
 56		xfrm4_rcv_encap_finish);
 57	return 0;
 58}
 59
 60/* If it's a keepalive packet, then just eat it.
 61 * If it's an encapsulated packet, then pass it to the
 62 * IPsec xfrm input.
 63 * Returns 0 if skb passed to xfrm or was dropped.
 64 * Returns >0 if skb should be passed to UDP.
 65 * Returns <0 if skb should be resubmitted (-ret is protocol)
 66 */
 67int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 68{
 69	struct udp_sock *up = udp_sk(sk);
 70	struct udphdr *uh;
 71	struct iphdr *iph;
 72	int iphlen, len;
 73
 74	__u8 *udpdata;
 75	__be32 *udpdata32;
 76	__u16 encap_type = up->encap_type;
 77
 78	/* if this is not encapsulated socket, then just return now */
 79	if (!encap_type)
 80		return 1;
 81
 82	/* If this is a paged skb, make sure we pull up
 83	 * whatever data we need to look at. */
 84	len = skb->len - sizeof(struct udphdr);
 85	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
 86		return 1;
 87
 88	/* Now we can get the pointers */
 89	uh = udp_hdr(skb);
 90	udpdata = (__u8 *)uh + sizeof(struct udphdr);
 91	udpdata32 = (__be32 *)udpdata;
 92
 93	switch (encap_type) {
 94	default:
 95	case UDP_ENCAP_ESPINUDP:
 96		/* Check if this is a keepalive packet.  If so, eat it. */
 97		if (len == 1 && udpdata[0] == 0xff) {
 98			goto drop;
 99		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
100			/* ESP Packet without Non-ESP header */
101			len = sizeof(struct udphdr);
102		} else
103			/* Must be an IKE packet.. pass it through */
104			return 1;
105		break;
106	case UDP_ENCAP_ESPINUDP_NON_IKE:
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 > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
111			   udpdata32[0] == 0 && udpdata32[1] == 0) {
112
113			/* ESP Packet with Non-IKE marker */
114			len = sizeof(struct udphdr) + 2 * sizeof(u32);
115		} else
116			/* Must be an IKE packet.. pass it through */
117			return 1;
118		break;
119	}
120
121	/* At this point we are sure that this is an ESPinUDP packet,
122	 * so we need to remove 'len' bytes from the packet (the UDP
123	 * header and optional ESP marker bytes) and then modify the
124	 * protocol to ESP, and then call into the transform receiver.
125	 */
126	if (skb_unclone(skb, GFP_ATOMIC))
127		goto drop;
128
129	/* Now we can update and verify the packet length... */
130	iph = ip_hdr(skb);
131	iphlen = iph->ihl << 2;
132	iph->tot_len = htons(ntohs(iph->tot_len) - len);
133	if (skb->len < iphlen + len) {
134		/* packet is too small!?! */
135		goto drop;
136	}
137
138	/* pull the data buffer up to the ESP header and set the
139	 * transport header to point to ESP.  Keep UDP on the stack
140	 * for later.
141	 */
142	__skb_pull(skb, len);
143	skb_reset_transport_header(skb);
144
145	/* process ESP */
146	return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
147
148drop:
149	kfree_skb(skb);
150	return 0;
151}
152
153int xfrm4_rcv(struct sk_buff *skb)
154{
155	return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
156}
157EXPORT_SYMBOL(xfrm4_rcv);
v4.17
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * xfrm4_input.c
  4 *
  5 * Changes:
  6 *	YOSHIFUJI Hideaki @USAGI
  7 *		Split up af-specific portion
  8 *	Derek Atkins <derek@ihtfp.com>
  9 *		Add Encapsulation support
 10 *
 11 */
 12
 13#include <linux/slab.h>
 14#include <linux/module.h>
 15#include <linux/string.h>
 16#include <linux/netfilter.h>
 17#include <linux/netfilter_ipv4.h>
 18#include <net/ip.h>
 19#include <net/xfrm.h>
 20
 21int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
 22{
 23	return xfrm4_extract_header(skb);
 24}
 25
 26static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
 27				   struct sk_buff *skb)
 28{
 29	return dst_input(skb);
 30}
 31
 32static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
 33					 struct sk_buff *skb)
 34{
 35	if (!skb_dst(skb)) {
 36		const struct iphdr *iph = ip_hdr(skb);
 37
 38		if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
 39					 iph->tos, skb->dev))
 40			goto drop;
 41	}
 42
 43	if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
 44		goto drop;
 45
 46	return 0;
 47drop:
 48	kfree_skb(skb);
 49	return NET_RX_DROP;
 50}
 51
 52int xfrm4_transport_finish(struct sk_buff *skb, int async)
 53{
 54	struct xfrm_offload *xo = xfrm_offload(skb);
 55	struct iphdr *iph = ip_hdr(skb);
 56
 57	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
 58
 59#ifndef CONFIG_NETFILTER
 60	if (!async)
 61		return -iph->protocol;
 62#endif
 63
 64	__skb_push(skb, skb->data - skb_network_header(skb));
 65	iph->tot_len = htons(skb->len);
 66	ip_send_check(iph);
 67
 68	if (xo && (xo->flags & XFRM_GRO)) {
 69		skb_mac_header_rebuild(skb);
 70		return 0;
 71	}
 72
 73	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
 74		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
 75		xfrm4_rcv_encap_finish);
 76	return 0;
 77}
 78
 79/* If it's a keepalive packet, then just eat it.
 80 * If it's an encapsulated packet, then pass it to the
 81 * IPsec xfrm input.
 82 * Returns 0 if skb passed to xfrm or was dropped.
 83 * Returns >0 if skb should be passed to UDP.
 84 * Returns <0 if skb should be resubmitted (-ret is protocol)
 85 */
 86int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 87{
 88	struct udp_sock *up = udp_sk(sk);
 89	struct udphdr *uh;
 90	struct iphdr *iph;
 91	int iphlen, len;
 92
 93	__u8 *udpdata;
 94	__be32 *udpdata32;
 95	__u16 encap_type = up->encap_type;
 96
 97	/* if this is not encapsulated socket, then just return now */
 98	if (!encap_type)
 99		return 1;
100
101	/* If this is a paged skb, make sure we pull up
102	 * whatever data we need to look at. */
103	len = skb->len - sizeof(struct udphdr);
104	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
105		return 1;
106
107	/* Now we can get the pointers */
108	uh = udp_hdr(skb);
109	udpdata = (__u8 *)uh + sizeof(struct udphdr);
110	udpdata32 = (__be32 *)udpdata;
111
112	switch (encap_type) {
113	default:
114	case UDP_ENCAP_ESPINUDP:
115		/* Check if this is a keepalive packet.  If so, eat it. */
116		if (len == 1 && udpdata[0] == 0xff) {
117			goto drop;
118		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
119			/* ESP Packet without Non-ESP header */
120			len = sizeof(struct udphdr);
121		} else
122			/* Must be an IKE packet.. pass it through */
123			return 1;
124		break;
125	case UDP_ENCAP_ESPINUDP_NON_IKE:
126		/* Check if this is a keepalive packet.  If so, eat it. */
127		if (len == 1 && udpdata[0] == 0xff) {
128			goto drop;
129		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
130			   udpdata32[0] == 0 && udpdata32[1] == 0) {
131
132			/* ESP Packet with Non-IKE marker */
133			len = sizeof(struct udphdr) + 2 * sizeof(u32);
134		} else
135			/* Must be an IKE packet.. pass it through */
136			return 1;
137		break;
138	}
139
140	/* At this point we are sure that this is an ESPinUDP packet,
141	 * so we need to remove 'len' bytes from the packet (the UDP
142	 * header and optional ESP marker bytes) and then modify the
143	 * protocol to ESP, and then call into the transform receiver.
144	 */
145	if (skb_unclone(skb, GFP_ATOMIC))
146		goto drop;
147
148	/* Now we can update and verify the packet length... */
149	iph = ip_hdr(skb);
150	iphlen = iph->ihl << 2;
151	iph->tot_len = htons(ntohs(iph->tot_len) - len);
152	if (skb->len < iphlen + len) {
153		/* packet is too small!?! */
154		goto drop;
155	}
156
157	/* pull the data buffer up to the ESP header and set the
158	 * transport header to point to ESP.  Keep UDP on the stack
159	 * for later.
160	 */
161	__skb_pull(skb, len);
162	skb_reset_transport_header(skb);
163
164	/* process ESP */
165	return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
166
167drop:
168	kfree_skb(skb);
169	return 0;
170}
171
172int xfrm4_rcv(struct sk_buff *skb)
173{
174	return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
175}
176EXPORT_SYMBOL(xfrm4_rcv);