// SPDX-License-Identifier: GPL-2.0 /* * xfrm6_input.c: based on net/ipv4/xfrm4_input.c * * Authors: * Mitsuru KANDA @USAGI * Kazunori MIYAZAWA @USAGI * Kunihiro Ishiguro * YOSHIFUJI Hideaki @USAGI * IPv6 support */ #include #include #include #include #include #include int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi, struct ip6_tnl *t) { XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t; XFRM_SPI_SKB_CB(skb)->family = AF_INET6; XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr); return xfrm_input(skb, nexthdr, spi, 0); } EXPORT_SYMBOL(xfrm6_rcv_spi); static int xfrm6_transport_finish2(struct net *net, struct sock *sk, struct sk_buff *skb) { if (xfrm_trans_queue(skb, ip6_rcv_finish)) { kfree_skb(skb); return NET_RX_DROP; } return 0; } int xfrm6_transport_finish(struct sk_buff *skb, int async) { struct xfrm_offload *xo = xfrm_offload(skb); int nhlen = skb->data - skb_network_header(skb); skb_network_header(skb)[IP6CB(skb)->nhoff] = XFRM_MODE_SKB_CB(skb)->protocol; #ifndef CONFIG_NETFILTER if (!async) return 1; #endif __skb_push(skb, nhlen); ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); skb_postpush_rcsum(skb, skb_network_header(skb), nhlen); if (xo && (xo->flags & XFRM_GRO)) { /* The full l2 header needs to be preserved so that re-injecting the packet at l2 * works correctly in the presence of vlan tags. */ skb_mac_header_rebuild_full(skb, xo->orig_mac_len); skb_reset_network_header(skb); skb_reset_transport_header(skb); return 0; } NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, dev_net(skb->dev), NULL, skb, skb->dev, NULL, xfrm6_transport_finish2); return 0; } /* If it's a keepalive packet, then just eat it. * If it's an encapsulated packet, then pass it to the * IPsec xfrm input. * Returns 0 if skb passed to xfrm or was dropped. * Returns >0 if skb should be passed to UDP. * Returns <0 if skb should be resubmitted (-ret is protocol) */ int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb) { struct udp_sock *up = udp_sk(sk); struct udphdr *uh; struct ipv6hdr *ip6h; int len; int ip6hlen = sizeof(struct ipv6hdr); __u8 *udpdata; __be32 *udpdata32; u16 encap_type; if (skb->protocol == htons(ETH_P_IP)) return xfrm4_udp_encap_rcv(sk, skb); encap_type = READ_ONCE(up->encap_type); /* if this is not encapsulated socket, then just return now */ if (!encap_type) return 1; /* If this is a paged skb, make sure we pull up * whatever data we need to look at. */ len = skb->len - sizeof(struct udphdr); if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8))) return 1; /* Now we can get the pointers */ uh = udp_hdr(skb); udpdata = (__u8 *)uh + sizeof(struct udphdr); udpdata32 = (__be32 *)udpdata; switch (encap_type) { default: case UDP_ENCAP_ESPINUDP: /* Check if this is a keepalive packet. If so, eat it. */ if (len == 1 && udpdata[0] == 0xff) { goto drop; } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) { /* ESP Packet without Non-ESP header */ len = sizeof(struct udphdr); } else /* Must be an IKE packet.. pass it through */ return 1; break; case UDP_ENCAP_ESPINUDP_NON_IKE: /* Check if this is a keepalive packet. If so, eat it. */ if (len == 1 && udpdata[0] == 0xff) { goto drop; } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) && udpdata32[0] == 0 && udpdata32[1] == 0) { /* ESP Packet with Non-IKE marker */ len = sizeof(struct udphdr) + 2 * sizeof(u32); } else /* Must be an IKE packet.. pass it through */ return 1; break; } /* At this point we are sure that this is an ESPinUDP packet, * so we need to remove 'len' bytes from the packet (the UDP * header and optional ESP marker bytes) and then modify the * protocol to ESP, and then call into the transform receiver. */ if (skb_unclone(skb, GFP_ATOMIC)) goto drop; /* Now we can update and verify the packet length... */ ip6h = ipv6_hdr(skb); ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len); if (skb->len < ip6hlen + len) { /* packet is too small!?! */ goto drop; } /* pull the data buffer up to the ESP header and set the * transport header to point to ESP. Keep UDP on the stack * for later. */ __skb_pull(skb, len); skb_reset_transport_header(skb); /* process ESP */ return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, encap_type); drop: kfree_skb(skb); return 0; } int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t) { return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff], 0, t); } EXPORT_SYMBOL(xfrm6_rcv_tnl); int xfrm6_rcv(struct sk_buff *skb) { return xfrm6_rcv_tnl(skb, NULL); } EXPORT_SYMBOL(xfrm6_rcv); int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr, xfrm_address_t *saddr, u8 proto) { struct net *net = dev_net(skb->dev); struct xfrm_state *x = NULL; struct sec_path *sp; int i = 0; sp = secpath_set(skb); if (!sp) { XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); goto drop; } if (1 + sp->len == XFRM_MAX_DEPTH) { XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR); goto drop; } for (i = 0; i < 3; i++) { xfrm_address_t *dst, *src; switch (i) { case 0: dst = daddr; src = saddr; break; case 1: /* lookup state with wild-card source address */ dst = daddr; src = (xfrm_address_t *)&in6addr_any; break; default: /* lookup state with wild-card addresses */ dst = (xfrm_address_t *)&in6addr_any; src = (xfrm_address_t *)&in6addr_any; break; } x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6); if (!x) continue; spin_lock(&x->lock); if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) && likely(x->km.state == XFRM_STATE_VALID) && !xfrm_state_check_expire(x)) { spin_unlock(&x->lock); if (x->type->input(x, skb) > 0) { /* found a valid state */ break; } } else spin_unlock(&x->lock); xfrm_state_put(x); x = NULL; } if (!x) { XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES); xfrm_audit_state_notfound_simple(skb, AF_INET6); goto drop; } sp->xvec[sp->len++] = x; spin_lock(&x->lock); x->curlft.bytes += skb->len; x->curlft.packets++; spin_unlock(&x->lock); return 1; drop: return -1; } EXPORT_SYMBOL(xfrm6_input_addr);