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