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 /* The full l2 header needs to be preserved so that re-injecting the packet at l2 60 * works correctly in the presence of vlan tags. 61 */ 62 skb_mac_header_rebuild_full(skb, xo->orig_mac_len); 63 skb_reset_network_header(skb); 64 skb_reset_transport_header(skb); 65 return 0; 66 } 67 68 NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, 69 dev_net(skb->dev), NULL, skb, skb->dev, NULL, 70 xfrm6_transport_finish2); 71 return 0; 72 } 73 74 /* If it's a keepalive packet, then just eat it. 75 * If it's an encapsulated packet, then pass it to the 76 * IPsec xfrm input. 77 * Returns 0 if skb passed to xfrm or was dropped. 78 * Returns >0 if skb should be passed to UDP. 79 * Returns <0 if skb should be resubmitted (-ret is protocol) 80 */ 81 int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) 82 { 83 struct udp_sock *up = udp_sk(sk); 84 struct udphdr *uh; 85 struct ipv6hdr *ip6h; 86 int len; 87 int ip6hlen = sizeof(struct ipv6hdr); 88 __u8 *udpdata; 89 __be32 *udpdata32; 90 u16 encap_type; 91 92 if (skb->protocol == htons(ETH_P_IP)) 93 return xfrm4_udp_encap_rcv(sk, skb); 94 95 encap_type = READ_ONCE(up->encap_type); 96 /* if this is not encapsulated socket, then just return now */ 97 if (!encap_type) 98 return 1; 99 100 /* If this is a paged skb, make sure we pull up 101 * whatever data we need to look at. */ 102 len = skb->len - sizeof(struct udphdr); 103 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) 104 return 1; 105 106 /* Now we can get the pointers */ 107 uh = udp_hdr(skb); 108 udpdata = (__u8 *)uh + sizeof(struct udphdr); 109 udpdata32 = (__be32 *)udpdata; 110 111 switch (encap_type) { 112 default: 113 case UDP_ENCAP_ESPINUDP: 114 /* Check if this is a keepalive packet. If so, eat it. */ 115 if (len == 1 && udpdata[0] == 0xff) { 116 goto drop; 117 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { 118 /* ESP Packet without Non-ESP header */ 119 len = sizeof(struct udphdr); 120 } else 121 /* Must be an IKE packet.. pass it through */ 122 return 1; 123 break; 124 case UDP_ENCAP_ESPINUDP_NON_IKE: 125 /* Check if this is a keepalive packet. If so, eat it. */ 126 if (len == 1 && udpdata[0] == 0xff) { 127 goto drop; 128 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && 129 udpdata32[0] == 0 && udpdata32[1] == 0) { 130 131 /* ESP Packet with Non-IKE marker */ 132 len = sizeof(struct udphdr) + 2 * sizeof(u32); 133 } else 134 /* Must be an IKE packet.. pass it through */ 135 return 1; 136 break; 137 } 138 139 /* At this point we are sure that this is an ESPinUDP packet, 140 * so we need to remove 'len' bytes from the packet (the UDP 141 * header and optional ESP marker bytes) and then modify the 142 * protocol to ESP, and then call into the transform receiver. 143 */ 144 if (skb_unclone(skb, GFP_ATOMIC)) 145 goto drop; 146 147 /* Now we can update and verify the packet length... */ 148 ip6h = ipv6_hdr(skb); 149 ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len); 150 if (skb->len < ip6hlen + len) { 151 /* packet is too small!?! */ 152 goto drop; 153 } 154 155 /* pull the data buffer up to the ESP header and set the 156 * transport header to point to ESP. Keep UDP on the stack 157 * for later. 158 */ 159 __skb_pull(skb, len); 160 skb_reset_transport_header(skb); 161 162 /* process ESP */ 163 return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); 164 165 drop: 166 kfree_skb(skb); 167 return 0; 168 } 169 170 int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t) 171 { 172 return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff], 173 0, t); 174 } 175 EXPORT_SYMBOL(xfrm6_rcv_tnl); 176 177 int xfrm6_rcv(struct sk_buff *skb) 178 { 179 return xfrm6_rcv_tnl(skb, NULL); 180 } 181 EXPORT_SYMBOL(xfrm6_rcv); 182 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr, 183 xfrm_address_t *saddr, u8 proto) 184 { 185 struct net *net = dev_net(skb->dev); 186 struct xfrm_state *x = NULL; 187 struct sec_path *sp; 188 int i = 0; 189 190 sp = secpath_set(skb); 191 if (!sp) { 192 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); 193 goto drop; 194 } 195 196 if (1 + sp->len == XFRM_MAX_DEPTH) { 197 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR); 198 goto drop; 199 } 200 201 for (i = 0; i < 3; i++) { 202 xfrm_address_t *dst, *src; 203 204 switch (i) { 205 case 0: 206 dst = daddr; 207 src = saddr; 208 break; 209 case 1: 210 /* lookup state with wild-card source address */ 211 dst = daddr; 212 src = (xfrm_address_t *)&in6addr_any; 213 break; 214 default: 215 /* lookup state with wild-card addresses */ 216 dst = (xfrm_address_t *)&in6addr_any; 217 src = (xfrm_address_t *)&in6addr_any; 218 break; 219 } 220 221 x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6); 222 if (!x) 223 continue; 224 225 spin_lock(&x->lock); 226 227 if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) && 228 likely(x->km.state == XFRM_STATE_VALID) && 229 !xfrm_state_check_expire(x)) { 230 spin_unlock(&x->lock); 231 if (x->type->input(x, skb) > 0) { 232 /* found a valid state */ 233 break; 234 } 235 } else 236 spin_unlock(&x->lock); 237 238 xfrm_state_put(x); 239 x = NULL; 240 } 241 242 if (!x) { 243 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES); 244 xfrm_audit_state_notfound_simple(skb, AF_INET6); 245 goto drop; 246 } 247 248 sp->xvec[sp->len++] = x; 249 250 spin_lock(&x->lock); 251 252 x->curlft.bytes += skb->len; 253 x->curlft.packets++; 254 255 spin_unlock(&x->lock); 256 257 return 1; 258 259 drop: 260 return -1; 261 } 262 EXPORT_SYMBOL(xfrm6_input_addr); 263