Pileus Git - ~andy/linux/blob - net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c

   1 /*
   2  * Copyright (C)2004 USAGI/WIDE Project
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Author:
   9  *      Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/ipv6.h>
  14 #include <linux/in6.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/icmp.h>
  19 #include <net/ipv6.h>
  20 #include <net/inet_frag.h>
  21
  22 #include <linux/netfilter_bridge.h>
  23 #include <linux/netfilter_ipv6.h>
  24 #include <linux/netfilter_ipv6/ip6_tables.h>
  25 #include <net/netfilter/nf_conntrack.h>
  26 #include <net/netfilter/nf_conntrack_helper.h>
  27 #include <net/netfilter/nf_conntrack_l4proto.h>
  28 #include <net/netfilter/nf_conntrack_l3proto.h>
  29 #include <net/netfilter/nf_conntrack_core.h>
  30 #include <net/netfilter/nf_conntrack_zones.h>
  31 #include <net/netfilter/nf_conntrack_seqadj.h>
  32 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  33 #include <net/netfilter/nf_nat_helper.h>
  34 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  35 #include <net/netfilter/nf_log.h>
  36
  37 static bool ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
  38                               struct nf_conntrack_tuple *tuple)
  39 {
  40         const u_int32_t *ap;
  41         u_int32_t _addrs[8];
  42
  43         ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr),
  44                                 sizeof(_addrs), _addrs);
  45         if (ap == NULL)
  46                 return false;
  47
  48         memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
  49         memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
  50
  51         return true;
  52 }
  53
  54 static bool ipv6_invert_tuple(struct nf_conntrack_tuple *tuple,
  55                               const struct nf_conntrack_tuple *orig)
  56 {
  57         memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6));
  58         memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6));
  59
  60         return true;
  61 }
  62
  63 static int ipv6_print_tuple(struct seq_file *s,
  64                             const struct nf_conntrack_tuple *tuple)
  65 {
  66         return seq_printf(s, "src=%pI6 dst=%pI6 ",
  67                           tuple->src.u3.ip6, tuple->dst.u3.ip6);
  68 }
  69
  70 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
  71                             unsigned int *dataoff, u_int8_t *protonum)
  72 {
  73         unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
  74         __be16 frag_off;
  75         int protoff;
  76         u8 nexthdr;
  77
  78         if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
  79                           &nexthdr, sizeof(nexthdr)) != 0) {
  80                 pr_debug("ip6_conntrack_core: can't get nexthdr\n");
  81                 return -NF_ACCEPT;
  82         }
  83         protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
  84         /*
  85          * (protoff == skb->len) means the packet has not data, just
  86          * IPv6 and possibly extensions headers, but it is tracked anyway
  87          */
  88         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
  89                 pr_debug("ip6_conntrack_core: can't find proto in pkt\n");
  90                 return -NF_ACCEPT;
  91         }
  92
  93         *dataoff = protoff;
  94         *protonum = nexthdr;
  95         return NF_ACCEPT;
  96 }
  97
  98 static unsigned int ipv6_helper(const struct nf_hook_ops *ops,
  99                                 struct sk_buff *skb,
 100                                 const struct net_device *in,
 101                                 const struct net_device *out,
 102                                 int (*okfn)(struct sk_buff *))
 103 {
 104         struct nf_conn *ct;
 105         const struct nf_conn_help *help;
 106         const struct nf_conntrack_helper *helper;
 107         enum ip_conntrack_info ctinfo;
 108         __be16 frag_off;
 109         int protoff;
 110         u8 nexthdr;
 111
 112         /* This is where we call the helper: as the packet goes out. */
 113         ct = nf_ct_get(skb, &ctinfo);
 114         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 115                 return NF_ACCEPT;
 116
 117         help = nfct_help(ct);
 118         if (!help)
 119                 return NF_ACCEPT;
 120         /* rcu_read_lock()ed by nf_hook_slow */
 121         helper = rcu_dereference(help->helper);
 122         if (!helper)
 123                 return NF_ACCEPT;
 124
 125         nexthdr = ipv6_hdr(skb)->nexthdr;
 126         protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
 127                                    &frag_off);
 128         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 129                 pr_debug("proto header not found\n");
 130                 return NF_ACCEPT;
 131         }
 132
 133         return helper->help(skb, protoff, ct, ctinfo);
 134 }
 135
 136 static unsigned int ipv6_confirm(const struct nf_hook_ops *ops,
 137                                  struct sk_buff *skb,
 138                                  const struct net_device *in,
 139                                  const struct net_device *out,
 140                                  int (*okfn)(struct sk_buff *))
 141 {
 142         struct nf_conn *ct;
 143         enum ip_conntrack_info ctinfo;
 144         unsigned char pnum = ipv6_hdr(skb)->nexthdr;
 145         int protoff;
 146         __be16 frag_off;
 147
 148         ct = nf_ct_get(skb, &ctinfo);
 149         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 150                 goto out;
 151
 152         protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
 153                                    &frag_off);
 154         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 155                 pr_debug("proto header not found\n");
 156                 goto out;
 157         }
 158
 159         /* adjust seqs for loopback traffic only in outgoing direction */
 160         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
 161             !nf_is_loopback_packet(skb)) {
 162                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
 163                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
 164                         return NF_DROP;
 165                 }
 166         }
 167 out:
 168         /* We've seen it coming out the other side: confirm it */
 169         return nf_conntrack_confirm(skb);
 170 }
 171
 172 static unsigned int ipv6_conntrack_in(const struct nf_hook_ops *ops,
 173                                       struct sk_buff *skb,
 174                                       const struct net_device *in,
 175                                       const struct net_device *out,
 176                                       int (*okfn)(struct sk_buff *))
 177 {
 178         return nf_conntrack_in(dev_net(in), PF_INET6, ops->hooknum, skb);
 179 }
 180
 181 static unsigned int ipv6_conntrack_local(const struct nf_hook_ops *ops,
 182                                          struct sk_buff *skb,
 183                                          const struct net_device *in,
 184                                          const struct net_device *out,
 185                                          int (*okfn)(struct sk_buff *))
 186 {
 187         /* root is playing with raw sockets. */
 188         if (skb->len < sizeof(struct ipv6hdr)) {
 189                 net_notice_ratelimited("ipv6_conntrack_local: packet too short\n");
 190                 return NF_ACCEPT;
 191         }
 192         return nf_conntrack_in(dev_net(out), PF_INET6, ops->hooknum, skb);
 193 }
 194
 195 static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = {
 196         {
 197                 .hook           = ipv6_conntrack_in,
 198                 .owner          = THIS_MODULE,
 199                 .pf             = NFPROTO_IPV6,
 200                 .hooknum        = NF_INET_PRE_ROUTING,
 201                 .priority       = NF_IP6_PRI_CONNTRACK,
 202         },
 203         {
 204                 .hook           = ipv6_conntrack_local,
 205                 .owner          = THIS_MODULE,
 206                 .pf             = NFPROTO_IPV6,
 207                 .hooknum        = NF_INET_LOCAL_OUT,
 208                 .priority       = NF_IP6_PRI_CONNTRACK,
 209         },
 210         {
 211                 .hook           = ipv6_helper,
 212                 .owner          = THIS_MODULE,
 213                 .pf             = NFPROTO_IPV6,
 214                 .hooknum        = NF_INET_POST_ROUTING,
 215                 .priority       = NF_IP6_PRI_CONNTRACK_HELPER,
 216         },
 217         {
 218                 .hook           = ipv6_confirm,
 219                 .owner          = THIS_MODULE,
 220                 .pf             = NFPROTO_IPV6,
 221                 .hooknum        = NF_INET_POST_ROUTING,
 222                 .priority       = NF_IP6_PRI_LAST,
 223         },
 224         {
 225                 .hook           = ipv6_helper,
 226                 .owner          = THIS_MODULE,
 227                 .pf             = NFPROTO_IPV6,
 228                 .hooknum        = NF_INET_LOCAL_IN,
 229                 .priority       = NF_IP6_PRI_CONNTRACK_HELPER,
 230         },
 231         {
 232                 .hook           = ipv6_confirm,
 233                 .owner          = THIS_MODULE,
 234                 .pf             = NFPROTO_IPV6,
 235                 .hooknum        = NF_INET_LOCAL_IN,
 236                 .priority       = NF_IP6_PRI_LAST-1,
 237         },
 238 };
 239
 240 static int
 241 ipv6_getorigdst(struct sock *sk, int optval, void __user *user, int *len)
 242 {
 243         const struct inet_sock *inet = inet_sk(sk);
 244         const struct ipv6_pinfo *inet6 = inet6_sk(sk);
 245         const struct nf_conntrack_tuple_hash *h;
 246         struct sockaddr_in6 sin6;
 247         struct nf_conntrack_tuple tuple = { .src.l3num = NFPROTO_IPV6 };
 248         struct nf_conn *ct;
 249
 250         tuple.src.u3.in6 = sk->sk_v6_rcv_saddr;
 251         tuple.src.u.tcp.port = inet->inet_sport;
 252         tuple.dst.u3.in6 = sk->sk_v6_daddr;
 253         tuple.dst.u.tcp.port = inet->inet_dport;
 254         tuple.dst.protonum = sk->sk_protocol;
 255
 256         if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP)
 257                 return -ENOPROTOOPT;
 258
 259         if (*len < 0 || (unsigned int) *len < sizeof(sin6))
 260                 return -EINVAL;
 261
 262         h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
 263         if (!h) {
 264                 pr_debug("IP6T_SO_ORIGINAL_DST: Can't find %pI6c/%u-%pI6c/%u.\n",
 265                          &tuple.src.u3.ip6, ntohs(tuple.src.u.tcp.port),
 266                          &tuple.dst.u3.ip6, ntohs(tuple.dst.u.tcp.port));
 267                 return -ENOENT;
 268         }
 269
 270         ct = nf_ct_tuplehash_to_ctrack(h);
 271
 272         sin6.sin6_family = AF_INET6;
 273         sin6.sin6_port = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.tcp.port;
 274         sin6.sin6_flowinfo = inet6->flow_label & IPV6_FLOWINFO_MASK;
 275         memcpy(&sin6.sin6_addr,
 276                 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in6,
 277                                         sizeof(sin6.sin6_addr));
 278
 279         nf_ct_put(ct);
 280         sin6.sin6_scope_id = ipv6_iface_scope_id(&sin6.sin6_addr,
 281                                                  sk->sk_bound_dev_if);
 282         return copy_to_user(user, &sin6, sizeof(sin6)) ? -EFAULT : 0;
 283 }
 284
 285 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 286
 287 #include <linux/netfilter/nfnetlink.h>
 288 #include <linux/netfilter/nfnetlink_conntrack.h>
 289
 290 static int ipv6_tuple_to_nlattr(struct sk_buff *skb,
 291                                 const struct nf_conntrack_tuple *tuple)
 292 {
 293         if (nla_put(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4,
 294                     &tuple->src.u3.ip6) ||
 295             nla_put(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4,
 296                     &tuple->dst.u3.ip6))
 297                 goto nla_put_failure;
 298         return 0;
 299
 300 nla_put_failure:
 301         return -1;
 302 }
 303
 304 static const struct nla_policy ipv6_nla_policy[CTA_IP_MAX+1] = {
 305         [CTA_IP_V6_SRC] = { .len = sizeof(u_int32_t)*4 },
 306         [CTA_IP_V6_DST] = { .len = sizeof(u_int32_t)*4 },
 307 };
 308
 309 static int ipv6_nlattr_to_tuple(struct nlattr *tb[],
 310                                 struct nf_conntrack_tuple *t)
 311 {
 312         if (!tb[CTA_IP_V6_SRC] || !tb[CTA_IP_V6_DST])
 313                 return -EINVAL;
 314
 315         memcpy(&t->src.u3.ip6, nla_data(tb[CTA_IP_V6_SRC]),
 316                sizeof(u_int32_t) * 4);
 317         memcpy(&t->dst.u3.ip6, nla_data(tb[CTA_IP_V6_DST]),
 318                sizeof(u_int32_t) * 4);
 319
 320         return 0;
 321 }
 322
 323 static int ipv6_nlattr_tuple_size(void)
 324 {
 325         return nla_policy_len(ipv6_nla_policy, CTA_IP_MAX + 1);
 326 }
 327 #endif
 328
 329 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 __read_mostly = {
 330         .l3proto                = PF_INET6,
 331         .name                   = "ipv6",
 332         .pkt_to_tuple           = ipv6_pkt_to_tuple,
 333         .invert_tuple           = ipv6_invert_tuple,
 334         .print_tuple            = ipv6_print_tuple,
 335         .get_l4proto            = ipv6_get_l4proto,
 336 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 337         .tuple_to_nlattr        = ipv6_tuple_to_nlattr,
 338         .nlattr_tuple_size      = ipv6_nlattr_tuple_size,
 339         .nlattr_to_tuple        = ipv6_nlattr_to_tuple,
 340         .nla_policy             = ipv6_nla_policy,
 341 #endif
 342         .me                     = THIS_MODULE,
 343 };
 344
 345 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6));
 346 MODULE_LICENSE("GPL");
 347 MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>");
 348
 349 static struct nf_sockopt_ops so_getorigdst6 = {
 350         .pf             = NFPROTO_IPV6,
 351         .get_optmin     = IP6T_SO_ORIGINAL_DST,
 352         .get_optmax     = IP6T_SO_ORIGINAL_DST + 1,
 353         .get            = ipv6_getorigdst,
 354         .owner          = THIS_MODULE,
 355 };
 356
 357 static int ipv6_net_init(struct net *net)
 358 {
 359         int ret = 0;
 360
 361         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_tcp6);
 362         if (ret < 0) {
 363                 pr_err("nf_conntrack_tcp6: pernet registration failed\n");
 364                 goto out;
 365         }
 366         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udp6);
 367         if (ret < 0) {
 368                 pr_err("nf_conntrack_udp6: pernet registration failed\n");
 369                 goto cleanup_tcp6;
 370         }
 371         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_icmpv6);
 372         if (ret < 0) {
 373                 pr_err("nf_conntrack_icmp6: pernet registration failed\n");
 374                 goto cleanup_udp6;
 375         }
 376         ret = nf_ct_l3proto_pernet_register(net, &nf_conntrack_l3proto_ipv6);
 377         if (ret < 0) {
 378                 pr_err("nf_conntrack_ipv6: pernet registration failed.\n");
 379                 goto cleanup_icmpv6;
 380         }
 381         return 0;
 382  cleanup_icmpv6:
 383         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmpv6);
 384  cleanup_udp6:
 385         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp6);
 386  cleanup_tcp6:
 387         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp6);
 388  out:
 389         return ret;
 390 }
 391
 392 static void ipv6_net_exit(struct net *net)
 393 {
 394         nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv6);
 395         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmpv6);
 396         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp6);
 397         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp6);
 398 }
 399
 400 static struct pernet_operations ipv6_net_ops = {
 401         .init = ipv6_net_init,
 402         .exit = ipv6_net_exit,
 403 };
 404
 405 static int __init nf_conntrack_l3proto_ipv6_init(void)
 406 {
 407         int ret = 0;
 408
 409         need_conntrack();
 410         nf_defrag_ipv6_enable();
 411
 412         ret = nf_register_sockopt(&so_getorigdst6);
 413         if (ret < 0) {
 414                 pr_err("Unable to register netfilter socket option\n");
 415                 return ret;
 416         }
 417
 418         ret = register_pernet_subsys(&ipv6_net_ops);
 419         if (ret < 0)
 420                 goto cleanup_sockopt;
 421
 422         ret = nf_register_hooks(ipv6_conntrack_ops,
 423                                 ARRAY_SIZE(ipv6_conntrack_ops));
 424         if (ret < 0) {
 425                 pr_err("nf_conntrack_ipv6: can't register pre-routing defrag "
 426                        "hook.\n");
 427                 goto cleanup_pernet;
 428         }
 429
 430         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_tcp6);
 431         if (ret < 0) {
 432                 pr_err("nf_conntrack_ipv6: can't register tcp6 proto.\n");
 433                 goto cleanup_hooks;
 434         }
 435
 436         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udp6);
 437         if (ret < 0) {
 438                 pr_err("nf_conntrack_ipv6: can't register udp6 proto.\n");
 439                 goto cleanup_tcp6;
 440         }
 441
 442         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_icmpv6);
 443         if (ret < 0) {
 444                 pr_err("nf_conntrack_ipv6: can't register icmpv6 proto.\n");
 445                 goto cleanup_udp6;
 446         }
 447
 448         ret = nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv6);
 449         if (ret < 0) {
 450                 pr_err("nf_conntrack_ipv6: can't register ipv6 proto.\n");
 451                 goto cleanup_icmpv6;
 452         }
 453         return ret;
 454
 455  cleanup_icmpv6:
 456         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmpv6);
 457  cleanup_udp6:
 458         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp6);
 459  cleanup_tcp6:
 460         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp6);
 461  cleanup_hooks:
 462         nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops));
 463  cleanup_pernet:
 464         unregister_pernet_subsys(&ipv6_net_ops);
 465  cleanup_sockopt:
 466         nf_unregister_sockopt(&so_getorigdst6);
 467         return ret;
 468 }
 469
 470 static void __exit nf_conntrack_l3proto_ipv6_fini(void)
 471 {
 472         synchronize_net();
 473         nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv6);
 474         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp6);
 475         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp6);
 476         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmpv6);
 477         nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops));
 478         unregister_pernet_subsys(&ipv6_net_ops);
 479         nf_unregister_sockopt(&so_getorigdst6);
 480 }
 481
 482 module_init(nf_conntrack_l3proto_ipv6_init);
 483 module_exit(nf_conntrack_l3proto_ipv6_fini);