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 case UDP_ENCAP_ESPINUDP_NON_IKE: 117 /* Check if this is a keepalive packet. If so, eat it. */ 118 if (len == 1 && udpdata[0] == 0xff) { 119 return -EINVAL; 120 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && 121 udpdata32[0] == 0 && udpdata32[1] == 0) { 122 123 /* ESP Packet with Non-IKE marker */ 124 len = sizeof(struct udphdr) + 2 * sizeof(u32); 125 } else 126 /* Must be an IKE packet.. pass it through */ 127 return 1; 128 break; 129 } 130 131 /* At this point we are sure that this is an ESPinUDP packet, 132 * so we need to remove 'len' bytes from the packet (the UDP 133 * header and optional ESP marker bytes) and then modify the 134 * protocol to ESP, and then call into the transform receiver. 135 */ 136 if (skb_unclone(skb, GFP_ATOMIC)) 137 return -EINVAL; 138 139 /* Now we can update and verify the packet length... */ 140 ip6h = ipv6_hdr(skb); 141 ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len); 142 if (skb->len < ip6hlen + len) { 143 /* packet is too small!?! */ 144 return -EINVAL; 145 } 146 147 /* pull the data buffer up to the ESP header and set the 148 * transport header to point to ESP. Keep UDP on the stack 149 * for later. 150 */ 151 if (pull) { 152 __skb_pull(skb, len); 153 skb_reset_transport_header(skb); 154 } else { 155 skb_set_transport_header(skb, len); 156 } 157 158 /* process ESP */ 159 return 0; 160 } 161 162 /* If it's a keepalive packet, then just eat it. 163 * If it's an encapsulated packet, then pass it to the 164 * IPsec xfrm input. 165 * Returns 0 if skb passed to xfrm or was dropped. 166 * Returns >0 if skb should be passed to UDP. 167 * Returns <0 if skb should be resubmitted (-ret is protocol) 168 */ 169 int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) 170 { 171 int ret; 172 173 if (skb->protocol == htons(ETH_P_IP)) 174 return xfrm4_udp_encap_rcv(sk, skb); 175 176 ret = __xfrm6_udp_encap_rcv(sk, skb, true); 177 if (!ret) 178 return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, 179 udp_sk(sk)->encap_type); 180 181 if (ret < 0) { 182 kfree_skb(skb); 183 return 0; 184 } 185 186 return ret; 187 } 188 189 struct sk_buff *xfrm6_gro_udp_encap_rcv(struct sock *sk, struct list_head *head, 190 struct sk_buff *skb) 191 { 192 int offset = skb_gro_offset(skb); 193 const struct net_offload *ops; 194 struct sk_buff *pp = NULL; 195 int ret; 196 197 if (skb->protocol == htons(ETH_P_IP)) 198 return xfrm4_gro_udp_encap_rcv(sk, head, skb); 199 200 offset = offset - sizeof(struct udphdr); 201 202 if (!pskb_pull(skb, offset)) 203 return NULL; 204 205 rcu_read_lock(); 206 ops = rcu_dereference(inet6_offloads[IPPROTO_ESP]); 207 if (!ops || !ops->callbacks.gro_receive) 208 goto out; 209 210 ret = __xfrm6_udp_encap_rcv(sk, skb, false); 211 if (ret) 212 goto out; 213 214 skb_push(skb, offset); 215 NAPI_GRO_CB(skb)->proto = IPPROTO_UDP; 216 217 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); 218 rcu_read_unlock(); 219 220 return pp; 221 222 out: 223 rcu_read_unlock(); 224 skb_push(skb, offset); 225 NAPI_GRO_CB(skb)->same_flow = 0; 226 NAPI_GRO_CB(skb)->flush = 1; 227 228 return NULL; 229 } 230 231 int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t) 232 { 233 return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff], 234 0, t); 235 } 236 EXPORT_SYMBOL(xfrm6_rcv_tnl); 237 238 int xfrm6_rcv(struct sk_buff *skb) 239 { 240 return xfrm6_rcv_tnl(skb, NULL); 241 } 242 EXPORT_SYMBOL(xfrm6_rcv); 243 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr, 244 xfrm_address_t *saddr, u8 proto) 245 { 246 struct net *net = dev_net(skb->dev); 247 struct xfrm_state *x = NULL; 248 struct sec_path *sp; 249 int i = 0; 250 251 sp = secpath_set(skb); 252 if (!sp) { 253 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); 254 goto drop; 255 } 256 257 if (1 + sp->len == XFRM_MAX_DEPTH) { 258 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR); 259 goto drop; 260 } 261 262 for (i = 0; i < 3; i++) { 263 xfrm_address_t *dst, *src; 264 265 switch (i) { 266 case 0: 267 dst = daddr; 268 src = saddr; 269 break; 270 case 1: 271 /* lookup state with wild-card source address */ 272 dst = daddr; 273 src = (xfrm_address_t *)&in6addr_any; 274 break; 275 default: 276 /* lookup state with wild-card addresses */ 277 dst = (xfrm_address_t *)&in6addr_any; 278 src = (xfrm_address_t *)&in6addr_any; 279 break; 280 } 281 282 x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6); 283 if (!x) 284 continue; 285 286 spin_lock(&x->lock); 287 288 if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) && 289 likely(x->km.state == XFRM_STATE_VALID) && 290 !xfrm_state_check_expire(x)) { 291 spin_unlock(&x->lock); 292 if (x->type->input(x, skb) > 0) { 293 /* found a valid state */ 294 break; 295 } 296 } else 297 spin_unlock(&x->lock); 298 299 xfrm_state_put(x); 300 x = NULL; 301 } 302 303 if (!x) { 304 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES); 305 xfrm_audit_state_notfound_simple(skb, AF_INET6); 306 goto drop; 307 } 308 309 sp->xvec[sp->len++] = x; 310 311 spin_lock(&x->lock); 312 313 x->curlft.bytes += skb->len; 314 x->curlft.packets++; 315 316 spin_unlock(&x->lock); 317 318 return 1; 319 320 drop: 321 return -1; 322 } 323 EXPORT_SYMBOL(xfrm6_input_addr); 324