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->data - skb_network_header(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 skb_mac_header_rebuild(skb); 62 skb_reset_transport_header(skb); 63 return 0; 64 } 65 66 NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, 67 dev_net(skb->dev), NULL, skb, skb->dev, NULL, 68 xfrm6_transport_finish2); 69 return 0; 70 } 71 72 static int __xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull) 73 { 74 struct udp_sock *up = udp_sk(sk); 75 struct udphdr *uh; 76 struct ipv6hdr *ip6h; 77 int len; 78 int ip6hlen = sizeof(struct ipv6hdr); 79 __u8 *udpdata; 80 __be32 *udpdata32; 81 u16 encap_type; 82 83 encap_type = READ_ONCE(up->encap_type); 84 /* if this is not encapsulated socket, then just return now */ 85 if (!encap_type) 86 return 1; 87 88 /* If this is a paged skb, make sure we pull up 89 * whatever data we need to look at. */ 90 len = skb->len - sizeof(struct udphdr); 91 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) 92 return 1; 93 94 /* Now we can get the pointers */ 95 uh = udp_hdr(skb); 96 udpdata = (__u8 *)uh + sizeof(struct udphdr); 97 udpdata32 = (__be32 *)udpdata; 98 99 switch (encap_type) { 100 default: 101 case UDP_ENCAP_ESPINUDP: 102 /* Check if this is a keepalive packet. If so, eat it. */ 103 if (len == 1 && udpdata[0] == 0xff) { 104 return -EINVAL; 105 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { 106 /* ESP Packet without Non-ESP header */ 107 len = sizeof(struct udphdr); 108 } else 109 /* Must be an IKE packet.. pass it through */ 110 return 1; 111 break; 112 case UDP_ENCAP_ESPINUDP_NON_IKE: 113 /* Check if this is a keepalive packet. If so, eat it. */ 114 if (len == 1 && udpdata[0] == 0xff) { 115 return -EINVAL; 116 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && 117 udpdata32[0] == 0 && udpdata32[1] == 0) { 118 119 /* ESP Packet with Non-IKE marker */ 120 len = sizeof(struct udphdr) + 2 * sizeof(u32); 121 } else 122 /* Must be an IKE packet.. pass it through */ 123 return 1; 124 break; 125 } 126 127 /* At this point we are sure that this is an ESPinUDP packet, 128 * so we need to remove 'len' bytes from the packet (the UDP 129 * header and optional ESP marker bytes) and then modify the 130 * protocol to ESP, and then call into the transform receiver. 131 */ 132 if (skb_unclone(skb, GFP_ATOMIC)) 133 return -EINVAL; 134 135 /* Now we can update and verify the packet length... */ 136 ip6h = ipv6_hdr(skb); 137 ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len); 138 if (skb->len < ip6hlen + len) { 139 /* packet is too small!?! */ 140 return -EINVAL; 141 } 142 143 /* pull the data buffer up to the ESP header and set the 144 * transport header to point to ESP. Keep UDP on the stack 145 * for later. 146 */ 147 if (pull) { 148 __skb_pull(skb, len); 149 skb_reset_transport_header(skb); 150 } else { 151 skb_set_transport_header(skb, len); 152 } 153 154 /* process ESP */ 155 return 0; 156 } 157 158 /* If it's a keepalive packet, then just eat it. 159 * If it's an encapsulated packet, then pass it to the 160 * IPsec xfrm input. 161 * Returns 0 if skb passed to xfrm or was dropped. 162 * Returns >0 if skb should be passed to UDP. 163 * Returns <0 if skb should be resubmitted (-ret is protocol) 164 */ 165 int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) 166 { 167 int ret; 168 169 if (skb->protocol == htons(ETH_P_IP)) 170 return xfrm4_udp_encap_rcv(sk, skb); 171 172 ret = __xfrm6_udp_encap_rcv(sk, skb, true); 173 if (!ret) 174 return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, 175 udp_sk(sk)->encap_type); 176 177 if (ret < 0) { 178 kfree_skb(skb); 179 return 0; 180 } 181 182 return ret; 183 } 184 185 struct sk_buff *xfrm6_gro_udp_encap_rcv(struct sock *sk, struct list_head *head, 186 struct sk_buff *skb) 187 { 188 int offset = skb_gro_offset(skb); 189 const struct net_offload *ops; 190 struct sk_buff *pp = NULL; 191 int ret; 192 193 if (skb->protocol == htons(ETH_P_IP)) 194 return xfrm4_gro_udp_encap_rcv(sk, head, skb); 195 196 offset = offset - sizeof(struct udphdr); 197 198 if (!pskb_pull(skb, offset)) 199 return NULL; 200 201 rcu_read_lock(); 202 ops = rcu_dereference(inet6_offloads[IPPROTO_ESP]); 203 if (!ops || !ops->callbacks.gro_receive) 204 goto out; 205 206 ret = __xfrm6_udp_encap_rcv(sk, skb, false); 207 if (ret) 208 goto out; 209 210 skb_push(skb, offset); 211 NAPI_GRO_CB(skb)->proto = IPPROTO_UDP; 212 213 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); 214 rcu_read_unlock(); 215 216 return pp; 217 218 out: 219 rcu_read_unlock(); 220 skb_push(skb, offset); 221 NAPI_GRO_CB(skb)->same_flow = 0; 222 NAPI_GRO_CB(skb)->flush = 1; 223 224 return NULL; 225 } 226 227 int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t) 228 { 229 return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff], 230 0, t); 231 } 232 EXPORT_SYMBOL(xfrm6_rcv_tnl); 233 234 int xfrm6_rcv(struct sk_buff *skb) 235 { 236 return xfrm6_rcv_tnl(skb, NULL); 237 } 238 EXPORT_SYMBOL(xfrm6_rcv); 239 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr, 240 xfrm_address_t *saddr, u8 proto) 241 { 242 struct net *net = dev_net(skb->dev); 243 struct xfrm_state *x = NULL; 244 struct sec_path *sp; 245 int i = 0; 246 247 sp = secpath_set(skb); 248 if (!sp) { 249 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); 250 goto drop; 251 } 252 253 if (1 + sp->len == XFRM_MAX_DEPTH) { 254 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR); 255 goto drop; 256 } 257 258 for (i = 0; i < 3; i++) { 259 xfrm_address_t *dst, *src; 260 261 switch (i) { 262 case 0: 263 dst = daddr; 264 src = saddr; 265 break; 266 case 1: 267 /* lookup state with wild-card source address */ 268 dst = daddr; 269 src = (xfrm_address_t *)&in6addr_any; 270 break; 271 default: 272 /* lookup state with wild-card addresses */ 273 dst = (xfrm_address_t *)&in6addr_any; 274 src = (xfrm_address_t *)&in6addr_any; 275 break; 276 } 277 278 x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6); 279 if (!x) 280 continue; 281 282 spin_lock(&x->lock); 283 284 if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) && 285 likely(x->km.state == XFRM_STATE_VALID) && 286 !xfrm_state_check_expire(x)) { 287 spin_unlock(&x->lock); 288 if (x->type->input(x, skb) > 0) { 289 /* found a valid state */ 290 break; 291 } 292 } else 293 spin_unlock(&x->lock); 294 295 xfrm_state_put(x); 296 x = NULL; 297 } 298 299 if (!x) { 300 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES); 301 xfrm_audit_state_notfound_simple(skb, AF_INET6); 302 goto drop; 303 } 304 305 sp->xvec[sp->len++] = x; 306 307 spin_lock(&x->lock); 308 309 x->curlft.bytes += skb->len; 310 x->curlft.packets++; 311 312 spin_unlock(&x->lock); 313 314 return 1; 315 316 drop: 317 return -1; 318 } 319 EXPORT_SYMBOL(xfrm6_input_addr); 320