1 /* 2 * Copyright (C) 2007-2008 BalaBit IT Ltd. 3 * Author: Krisztian Kovacs 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 */ 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 #include <linux/module.h> 12 #include <linux/skbuff.h> 13 #include <net/tcp.h> 14 #include <net/udp.h> 15 #include <net/icmp.h> 16 #include <net/sock.h> 17 #include <net/inet_sock.h> 18 #include <net/inet6_hashtables.h> 19 #include <net/netfilter/ipv6/nf_defrag_ipv6.h> 20 #include <net/netfilter/nf_socket.h> 21 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 22 #include <net/netfilter/nf_conntrack.h> 23 #endif 24 25 static int 26 extract_icmp6_fields(const struct sk_buff *skb, 27 unsigned int outside_hdrlen, 28 int *protocol, 29 const struct in6_addr **raddr, 30 const struct in6_addr **laddr, 31 __be16 *rport, 32 __be16 *lport, 33 struct ipv6hdr *ipv6_var) 34 { 35 const struct ipv6hdr *inside_iph; 36 struct icmp6hdr *icmph, _icmph; 37 __be16 *ports, _ports[2]; 38 u8 inside_nexthdr; 39 __be16 inside_fragoff; 40 int inside_hdrlen; 41 42 icmph = skb_header_pointer(skb, outside_hdrlen, 43 sizeof(_icmph), &_icmph); 44 if (icmph == NULL) 45 return 1; 46 47 if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK) 48 return 1; 49 50 inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), 51 sizeof(*ipv6_var), ipv6_var); 52 if (inside_iph == NULL) 53 return 1; 54 inside_nexthdr = inside_iph->nexthdr; 55 56 inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + 57 sizeof(*ipv6_var), 58 &inside_nexthdr, &inside_fragoff); 59 if (inside_hdrlen < 0) 60 return 1; /* hjm: Packet has no/incomplete transport layer headers. */ 61 62 if (inside_nexthdr != IPPROTO_TCP && 63 inside_nexthdr != IPPROTO_UDP) 64 return 1; 65 66 ports = skb_header_pointer(skb, inside_hdrlen, 67 sizeof(_ports), &_ports); 68 if (ports == NULL) 69 return 1; 70 71 /* the inside IP packet is the one quoted from our side, thus 72 * its saddr is the local address */ 73 *protocol = inside_nexthdr; 74 *laddr = &inside_iph->saddr; 75 *lport = ports[0]; 76 *raddr = &inside_iph->daddr; 77 *rport = ports[1]; 78 79 return 0; 80 } 81 82 static struct sock * 83 nf_socket_get_sock_v6(struct net *net, struct sk_buff *skb, int doff, 84 const u8 protocol, 85 const struct in6_addr *saddr, const struct in6_addr *daddr, 86 const __be16 sport, const __be16 dport, 87 const struct net_device *in) 88 { 89 switch (protocol) { 90 case IPPROTO_TCP: 91 return inet6_lookup(net, &tcp_hashinfo, skb, doff, 92 saddr, sport, daddr, dport, 93 in->ifindex); 94 case IPPROTO_UDP: 95 return udp6_lib_lookup(net, saddr, sport, daddr, dport, 96 in->ifindex); 97 } 98 99 return NULL; 100 } 101 102 struct sock *nf_sk_lookup_slow_v6(struct net *net, const struct sk_buff *skb, 103 const struct net_device *indev) 104 { 105 __be16 uninitialized_var(dport), uninitialized_var(sport); 106 const struct in6_addr *daddr = NULL, *saddr = NULL; 107 struct ipv6hdr *iph = ipv6_hdr(skb); 108 struct sk_buff *data_skb = NULL; 109 int doff = 0; 110 int thoff = 0, tproto; 111 112 tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL); 113 if (tproto < 0) { 114 pr_debug("unable to find transport header in IPv6 packet, dropping\n"); 115 return NULL; 116 } 117 118 if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) { 119 struct udphdr _hdr, *hp; 120 121 hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr); 122 if (hp == NULL) 123 return NULL; 124 125 saddr = &iph->saddr; 126 sport = hp->source; 127 daddr = &iph->daddr; 128 dport = hp->dest; 129 data_skb = (struct sk_buff *)skb; 130 doff = tproto == IPPROTO_TCP ? 131 thoff + __tcp_hdrlen((struct tcphdr *)hp) : 132 thoff + sizeof(*hp); 133 134 } else if (tproto == IPPROTO_ICMPV6) { 135 struct ipv6hdr ipv6_var; 136 137 if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr, 138 &sport, &dport, &ipv6_var)) 139 return NULL; 140 } else { 141 return NULL; 142 } 143 144 return nf_socket_get_sock_v6(net, data_skb, doff, tproto, saddr, daddr, 145 sport, dport, indev); 146 } 147 EXPORT_SYMBOL_GPL(nf_sk_lookup_slow_v6); 148 149 MODULE_LICENSE("GPL"); 150 MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler"); 151 MODULE_DESCRIPTION("Netfilter IPv6 socket lookup infrastructure"); 152