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 20 int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi, 21 struct ip6_tnl *t) 22 { 23 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t; 24 XFRM_SPI_SKB_CB(skb)->family = AF_INET6; 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); 29 30 static int xfrm6_transport_finish2(struct net *net, struct sock *sk, 31 struct sk_buff *skb) 32 { 33 if (xfrm_trans_queue(skb, ip6_rcv_finish)) { 34 kfree_skb(skb); 35 return NET_RX_DROP; 36 } 37 38 return 0; 39 } 40 41 int xfrm6_transport_finish(struct sk_buff *skb, int async) 42 { 43 struct xfrm_offload *xo = xfrm_offload(skb); 44 int nhlen = skb->data - skb_network_header(skb); 45 46 skb_network_header(skb)[IP6CB(skb)->nhoff] = 47 XFRM_MODE_SKB_CB(skb)->protocol; 48 49 #ifndef CONFIG_NETFILTER 50 if (!async) 51 return 1; 52 #endif 53 54 __skb_push(skb, nhlen); 55 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 56 skb_postpush_rcsum(skb, skb_network_header(skb), nhlen); 57 58 if (xo && (xo->flags & XFRM_GRO)) { 59 skb_mac_header_rebuild(skb); 60 skb_reset_transport_header(skb); 61 return 0; 62 } 63 64 NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, 65 dev_net(skb->dev), NULL, skb, skb->dev, NULL, 66 xfrm6_transport_finish2); 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; 161 } 162 163 int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t) 164 { 165 return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff], 166 0, t); 167 } 168 EXPORT_SYMBOL(xfrm6_rcv_tnl); 169 170 int xfrm6_rcv(struct sk_buff *skb) 171 { 172 return xfrm6_rcv_tnl(skb, NULL); 173 } 174 EXPORT_SYMBOL(xfrm6_rcv); 175 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr, 176 xfrm_address_t *saddr, u8 proto) 177 { 178 struct net *net = dev_net(skb->dev); 179 struct xfrm_state *x = NULL; 180 struct sec_path *sp; 181 int i = 0; 182 183 sp = secpath_set(skb); 184 if (!sp) { 185 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); 186 goto drop; 187 } 188 189 if (1 + sp->len == XFRM_MAX_DEPTH) { 190 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR); 191 goto drop; 192 } 193 194 for (i = 0; i < 3; i++) { 195 xfrm_address_t *dst, *src; 196 197 switch (i) { 198 case 0: 199 dst = daddr; 200 src = saddr; 201 break; 202 case 1: 203 /* lookup state with wild-card source address */ 204 dst = daddr; 205 src = (xfrm_address_t *)&in6addr_any; 206 break; 207 default: 208 /* lookup state with wild-card addresses */ 209 dst = (xfrm_address_t *)&in6addr_any; 210 src = (xfrm_address_t *)&in6addr_any; 211 break; 212 } 213 214 x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6); 215 if (!x) 216 continue; 217 218 spin_lock(&x->lock); 219 220 if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) && 221 likely(x->km.state == XFRM_STATE_VALID) && 222 !xfrm_state_check_expire(x)) { 223 spin_unlock(&x->lock); 224 if (x->type->input(x, skb) > 0) { 225 /* found a valid state */ 226 break; 227 } 228 } else 229 spin_unlock(&x->lock); 230 231 xfrm_state_put(x); 232 x = NULL; 233 } 234 235 if (!x) { 236 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES); 237 xfrm_audit_state_notfound_simple(skb, AF_INET6); 238 goto drop; 239 } 240 241 sp->xvec[sp->len++] = x; 242 243 spin_lock(&x->lock); 244 245 x->curlft.bytes += skb->len; 246 x->curlft.packets++; 247 248 spin_unlock(&x->lock); 249 250 return 1; 251 252 drop: 253 return -1; 254 } 255 EXPORT_SYMBOL(xfrm6_input_addr); 256