net/netfilter/nf_conntrack_proto.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/types.h>
   4 #include <linux/netfilter.h>
   5 #include <linux/module.h>
   6 #include <linux/slab.h>
   7 #include <linux/mutex.h>
   8 #include <linux/vmalloc.h>
   9 #include <linux/stddef.h>
  10 #include <linux/err.h>
  11 #include <linux/percpu.h>
  12 #include <linux/notifier.h>
  13 #include <linux/kernel.h>
  14 #include <linux/netdevice.h>
  15
  16 #include <net/netfilter/nf_conntrack.h>
  17 #include <net/netfilter/nf_conntrack_l4proto.h>
  18 #include <net/netfilter/nf_conntrack_core.h>
  19 #include <net/netfilter/nf_log.h>
  20
  21 #include <linux/ip.h>
  22 #include <linux/icmp.h>
  23 #include <linux/sysctl.h>
  24 #include <net/route.h>
  25 #include <net/ip.h>
  26
  27 #include <linux/netfilter_ipv4.h>
  28 #include <linux/netfilter_ipv6.h>
  29 #include <linux/netfilter_ipv6/ip6_tables.h>
  30 #include <net/netfilter/nf_conntrack_helper.h>
  31 #include <net/netfilter/nf_conntrack_zones.h>
  32 #include <net/netfilter/nf_conntrack_seqadj.h>
  33 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  34 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  35 #include <net/netfilter/nf_nat_helper.h>
  36 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
  37 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  38
  39 #include <linux/ipv6.h>
  40 #include <linux/in6.h>
  41 #include <net/ipv6.h>
  42 #include <net/inet_frag.h>
  43
  44 extern unsigned int nf_conntrack_net_id;
  45
  46 static struct nf_conntrack_l4proto __rcu **nf_ct_protos[NFPROTO_NUMPROTO] __read_mostly;
  47
  48 static DEFINE_MUTEX(nf_ct_proto_mutex);
  49
  50 #ifdef CONFIG_SYSCTL
  51 static int
  52 nf_ct_register_sysctl(struct net *net,
  53                       struct ctl_table_header **header,
  54                       const char *path,
  55                       struct ctl_table *table)
  56 {
  57         if (*header == NULL) {
  58                 *header = register_net_sysctl(net, path, table);
  59                 if (*header == NULL)
  60                         return -ENOMEM;
  61         }
  62
  63         return 0;
  64 }
  65
  66 static void
  67 nf_ct_unregister_sysctl(struct ctl_table_header **header,
  68                         struct ctl_table **table,
  69                         unsigned int users)
  70 {
  71         if (users > 0)
  72                 return;
  73
  74         unregister_net_sysctl_table(*header);
  75         kfree(*table);
  76         *header = NULL;
  77         *table = NULL;
  78 }
  79
  80 __printf(5, 6)
  81 void nf_l4proto_log_invalid(const struct sk_buff *skb,
  82                             struct net *net,
  83                             u16 pf, u8 protonum,
  84                             const char *fmt, ...)
  85 {
  86         struct va_format vaf;
  87         va_list args;
  88
  89         if (net->ct.sysctl_log_invalid != protonum ||
  90             net->ct.sysctl_log_invalid != IPPROTO_RAW)
  91                 return;
  92
  93         va_start(args, fmt);
  94         vaf.fmt = fmt;
  95         vaf.va = &args;
  96
  97         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
  98                       "nf_ct_proto_%d: %pV ", protonum, &vaf);
  99         va_end(args);
 100 }
 101 EXPORT_SYMBOL_GPL(nf_l4proto_log_invalid);
 102
 103 __printf(3, 4)
 104 void nf_ct_l4proto_log_invalid(const struct sk_buff *skb,
 105                                const struct nf_conn *ct,
 106                                const char *fmt, ...)
 107 {
 108         struct va_format vaf;
 109         struct net *net;
 110         va_list args;
 111
 112         net = nf_ct_net(ct);
 113         if (likely(net->ct.sysctl_log_invalid == 0))
 114                 return;
 115
 116         va_start(args, fmt);
 117         vaf.fmt = fmt;
 118         vaf.va = &args;
 119
 120         nf_l4proto_log_invalid(skb, net, nf_ct_l3num(ct),
 121                                nf_ct_protonum(ct), "%pV", &vaf);
 122         va_end(args);
 123 }
 124 EXPORT_SYMBOL_GPL(nf_ct_l4proto_log_invalid);
 125 #endif
 126
 127 const struct nf_conntrack_l4proto *
 128 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
 129 {
 130         if (unlikely(l3proto >= NFPROTO_NUMPROTO || nf_ct_protos[l3proto] == NULL))
 131                 return &nf_conntrack_l4proto_generic;
 132
 133         return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
 134 }
 135 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
 136
 137 const struct nf_conntrack_l4proto *
 138 nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num)
 139 {
 140         const struct nf_conntrack_l4proto *p;
 141
 142         rcu_read_lock();
 143         p = __nf_ct_l4proto_find(l3num, l4num);
 144         if (!try_module_get(p->me))
 145                 p = &nf_conntrack_l4proto_generic;
 146         rcu_read_unlock();
 147
 148         return p;
 149 }
 150 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
 151
 152 void nf_ct_l4proto_put(const struct nf_conntrack_l4proto *p)
 153 {
 154         module_put(p->me);
 155 }
 156 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
 157
 158 static int kill_l4proto(struct nf_conn *i, void *data)
 159 {
 160         const struct nf_conntrack_l4proto *l4proto;
 161         l4proto = data;
 162         return nf_ct_protonum(i) == l4proto->l4proto &&
 163                nf_ct_l3num(i) == l4proto->l3proto;
 164 }
 165
 166 static struct nf_proto_net *nf_ct_l4proto_net(struct net *net,
 167                                 const struct nf_conntrack_l4proto *l4proto)
 168 {
 169         if (l4proto->get_net_proto) {
 170                 /* statically built-in protocols use static per-net */
 171                 return l4proto->get_net_proto(net);
 172         } else if (l4proto->net_id) {
 173                 /* ... and loadable protocols use dynamic per-net */
 174                 return net_generic(net, *l4proto->net_id);
 175         }
 176         return NULL;
 177 }
 178
 179 static
 180 int nf_ct_l4proto_register_sysctl(struct net *net,
 181                                   struct nf_proto_net *pn,
 182                                   const struct nf_conntrack_l4proto *l4proto)
 183 {
 184         int err = 0;
 185
 186 #ifdef CONFIG_SYSCTL
 187         if (pn->ctl_table != NULL) {
 188                 err = nf_ct_register_sysctl(net,
 189                                             &pn->ctl_table_header,
 190                                             "net/netfilter",
 191                                             pn->ctl_table);
 192                 if (err < 0) {
 193                         if (!pn->users) {
 194                                 kfree(pn->ctl_table);
 195                                 pn->ctl_table = NULL;
 196                         }
 197                 }
 198         }
 199 #endif /* CONFIG_SYSCTL */
 200         return err;
 201 }
 202
 203 static
 204 void nf_ct_l4proto_unregister_sysctl(struct net *net,
 205                                 struct nf_proto_net *pn,
 206                                 const struct nf_conntrack_l4proto *l4proto)
 207 {
 208 #ifdef CONFIG_SYSCTL
 209         if (pn->ctl_table_header != NULL)
 210                 nf_ct_unregister_sysctl(&pn->ctl_table_header,
 211                                         &pn->ctl_table,
 212                                         pn->users);
 213 #endif /* CONFIG_SYSCTL */
 214 }
 215
 216 /* FIXME: Allow NULL functions and sub in pointers to generic for
 217    them. --RR */
 218 int nf_ct_l4proto_register_one(const struct nf_conntrack_l4proto *l4proto)
 219 {
 220         int ret = 0;
 221
 222         if (l4proto->l3proto >= ARRAY_SIZE(nf_ct_protos))
 223                 return -EBUSY;
 224
 225         if ((l4proto->to_nlattr && l4proto->nlattr_size == 0) ||
 226             (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
 227                 return -EINVAL;
 228
 229         mutex_lock(&nf_ct_proto_mutex);
 230         if (!nf_ct_protos[l4proto->l3proto]) {
 231                 /* l3proto may be loaded latter. */
 232                 struct nf_conntrack_l4proto __rcu **proto_array;
 233                 int i;
 234
 235                 proto_array =
 236                         kmalloc_array(MAX_NF_CT_PROTO,
 237                                       sizeof(struct nf_conntrack_l4proto *),
 238                                       GFP_KERNEL);
 239                 if (proto_array == NULL) {
 240                         ret = -ENOMEM;
 241                         goto out_unlock;
 242                 }
 243
 244                 for (i = 0; i < MAX_NF_CT_PROTO; i++)
 245                         RCU_INIT_POINTER(proto_array[i],
 246                                          &nf_conntrack_l4proto_generic);
 247
 248                 /* Before making proto_array visible to lockless readers,
 249                  * we must make sure its content is committed to memory.
 250                  */
 251                 smp_wmb();
 252
 253                 nf_ct_protos[l4proto->l3proto] = proto_array;
 254         } else if (rcu_dereference_protected(
 255                         nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 256                         lockdep_is_held(&nf_ct_proto_mutex)
 257                         ) != &nf_conntrack_l4proto_generic) {
 258                 ret = -EBUSY;
 259                 goto out_unlock;
 260         }
 261
 262         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 263                            l4proto);
 264 out_unlock:
 265         mutex_unlock(&nf_ct_proto_mutex);
 266         return ret;
 267 }
 268 EXPORT_SYMBOL_GPL(nf_ct_l4proto_register_one);
 269
 270 int nf_ct_l4proto_pernet_register_one(struct net *net,
 271                                 const struct nf_conntrack_l4proto *l4proto)
 272 {
 273         int ret = 0;
 274         struct nf_proto_net *pn = NULL;
 275
 276         if (l4proto->init_net) {
 277                 ret = l4proto->init_net(net, l4proto->l3proto);
 278                 if (ret < 0)
 279                         goto out;
 280         }
 281
 282         pn = nf_ct_l4proto_net(net, l4proto);
 283         if (pn == NULL)
 284                 goto out;
 285
 286         ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto);
 287         if (ret < 0)
 288                 goto out;
 289
 290         pn->users++;
 291 out:
 292         return ret;
 293 }
 294 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register_one);
 295
 296 static void __nf_ct_l4proto_unregister_one(const struct nf_conntrack_l4proto *l4proto)
 297
 298 {
 299         BUG_ON(l4proto->l3proto >= ARRAY_SIZE(nf_ct_protos));
 300
 301         BUG_ON(rcu_dereference_protected(
 302                         nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 303                         lockdep_is_held(&nf_ct_proto_mutex)
 304                         ) != l4proto);
 305         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
 306                            &nf_conntrack_l4proto_generic);
 307 }
 308
 309 void nf_ct_l4proto_unregister_one(const struct nf_conntrack_l4proto *l4proto)
 310 {
 311         mutex_lock(&nf_ct_proto_mutex);
 312         __nf_ct_l4proto_unregister_one(l4proto);
 313         mutex_unlock(&nf_ct_proto_mutex);
 314
 315         synchronize_net();
 316         /* Remove all contrack entries for this protocol */
 317         nf_ct_iterate_destroy(kill_l4proto, (void *)l4proto);
 318 }
 319 EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister_one);
 320
 321 void nf_ct_l4proto_pernet_unregister_one(struct net *net,
 322                                 const struct nf_conntrack_l4proto *l4proto)
 323 {
 324         struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto);
 325
 326         if (pn == NULL)
 327                 return;
 328
 329         pn->users--;
 330         nf_ct_l4proto_unregister_sysctl(net, pn, l4proto);
 331 }
 332 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister_one);
 333
 334 static void
 335 nf_ct_l4proto_unregister(const struct nf_conntrack_l4proto * const l4proto[],
 336                          unsigned int num_proto)
 337 {
 338         int i;
 339
 340         mutex_lock(&nf_ct_proto_mutex);
 341         for (i = 0; i < num_proto; i++)
 342                 __nf_ct_l4proto_unregister_one(l4proto[i]);
 343         mutex_unlock(&nf_ct_proto_mutex);
 344
 345         synchronize_net();
 346
 347         for (i = 0; i < num_proto; i++)
 348                 nf_ct_iterate_destroy(kill_l4proto, (void *)l4proto[i]);
 349 }
 350
 351 static int
 352 nf_ct_l4proto_register(const struct nf_conntrack_l4proto * const l4proto[],
 353                        unsigned int num_proto)
 354 {
 355         int ret = -EINVAL, ver;
 356         unsigned int i;
 357
 358         for (i = 0; i < num_proto; i++) {
 359                 ret = nf_ct_l4proto_register_one(l4proto[i]);
 360                 if (ret < 0)
 361                         break;
 362         }
 363         if (i != num_proto) {
 364                 ver = l4proto[i]->l3proto == PF_INET6 ? 6 : 4;
 365                 pr_err("nf_conntrack_ipv%d: can't register l4 %d proto.\n",
 366                        ver, l4proto[i]->l4proto);
 367                 nf_ct_l4proto_unregister(l4proto, i);
 368         }
 369         return ret;
 370 }
 371
 372 int nf_ct_l4proto_pernet_register(struct net *net,
 373                                   const struct nf_conntrack_l4proto *const l4proto[],
 374                                   unsigned int num_proto)
 375 {
 376         int ret = -EINVAL;
 377         unsigned int i;
 378
 379         for (i = 0; i < num_proto; i++) {
 380                 ret = nf_ct_l4proto_pernet_register_one(net, l4proto[i]);
 381                 if (ret < 0)
 382                         break;
 383         }
 384         if (i != num_proto) {
 385                 pr_err("nf_conntrack_proto_%d %d: pernet registration failed\n",
 386                        l4proto[i]->l4proto,
 387                        l4proto[i]->l3proto == PF_INET6 ? 6 : 4);
 388                 nf_ct_l4proto_pernet_unregister(net, l4proto, i);
 389         }
 390         return ret;
 391 }
 392 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register);
 393
 394 void nf_ct_l4proto_pernet_unregister(struct net *net,
 395                                 const struct nf_conntrack_l4proto *const l4proto[],
 396                                 unsigned int num_proto)
 397 {
 398         while (num_proto-- != 0)
 399                 nf_ct_l4proto_pernet_unregister_one(net, l4proto[num_proto]);
 400 }
 401 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister);
 402
 403 static unsigned int ipv4_helper(void *priv,
 404                                 struct sk_buff *skb,
 405                                 const struct nf_hook_state *state)
 406 {
 407         struct nf_conn *ct;
 408         enum ip_conntrack_info ctinfo;
 409         const struct nf_conn_help *help;
 410         const struct nf_conntrack_helper *helper;
 411
 412         /* This is where we call the helper: as the packet goes out. */
 413         ct = nf_ct_get(skb, &ctinfo);
 414         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 415                 return NF_ACCEPT;
 416
 417         help = nfct_help(ct);
 418         if (!help)
 419                 return NF_ACCEPT;
 420
 421         /* rcu_read_lock()ed by nf_hook_thresh */
 422         helper = rcu_dereference(help->helper);
 423         if (!helper)
 424                 return NF_ACCEPT;
 425
 426         return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
 427                             ct, ctinfo);
 428 }
 429
 430 static unsigned int ipv4_confirm(void *priv,
 431                                  struct sk_buff *skb,
 432                                  const struct nf_hook_state *state)
 433 {
 434         struct nf_conn *ct;
 435         enum ip_conntrack_info ctinfo;
 436
 437         ct = nf_ct_get(skb, &ctinfo);
 438         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 439                 goto out;
 440
 441         /* adjust seqs for loopback traffic only in outgoing direction */
 442         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
 443             !nf_is_loopback_packet(skb)) {
 444                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
 445                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
 446                         return NF_DROP;
 447                 }
 448         }
 449 out:
 450         /* We've seen it coming out the other side: confirm it */
 451         return nf_conntrack_confirm(skb);
 452 }
 453
 454 static unsigned int ipv4_conntrack_in(void *priv,
 455                                       struct sk_buff *skb,
 456                                       const struct nf_hook_state *state)
 457 {
 458         return nf_conntrack_in(state->net, PF_INET, state->hook, skb);
 459 }
 460
 461 static unsigned int ipv4_conntrack_local(void *priv,
 462                                          struct sk_buff *skb,
 463                                          const struct nf_hook_state *state)
 464 {
 465         if (ip_is_fragment(ip_hdr(skb))) { /* IP_NODEFRAG setsockopt set */
 466                 enum ip_conntrack_info ctinfo;
 467                 struct nf_conn *tmpl;
 468
 469                 tmpl = nf_ct_get(skb, &ctinfo);
 470                 if (tmpl && nf_ct_is_template(tmpl)) {
 471                         /* when skipping ct, clear templates to avoid fooling
 472                          * later targets/matches
 473                          */
 474                         skb->_nfct = 0;
 475                         nf_ct_put(tmpl);
 476                 }
 477                 return NF_ACCEPT;
 478         }
 479
 480         return nf_conntrack_in(state->net, PF_INET, state->hook, skb);
 481 }
 482
 483 /* Connection tracking may drop packets, but never alters them, so
 484  * make it the first hook.
 485  */
 486 static const struct nf_hook_ops ipv4_conntrack_ops[] = {
 487         {
 488                 .hook           = ipv4_conntrack_in,
 489                 .pf             = NFPROTO_IPV4,
 490                 .hooknum        = NF_INET_PRE_ROUTING,
 491                 .priority       = NF_IP_PRI_CONNTRACK,
 492         },
 493         {
 494                 .hook           = ipv4_conntrack_local,
 495                 .pf             = NFPROTO_IPV4,
 496                 .hooknum        = NF_INET_LOCAL_OUT,
 497                 .priority       = NF_IP_PRI_CONNTRACK,
 498         },
 499         {
 500                 .hook           = ipv4_helper,
 501                 .pf             = NFPROTO_IPV4,
 502                 .hooknum        = NF_INET_POST_ROUTING,
 503                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
 504         },
 505         {
 506                 .hook           = ipv4_confirm,
 507                 .pf             = NFPROTO_IPV4,
 508                 .hooknum        = NF_INET_POST_ROUTING,
 509                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
 510         },
 511         {
 512                 .hook           = ipv4_helper,
 513                 .pf             = NFPROTO_IPV4,
 514                 .hooknum        = NF_INET_LOCAL_IN,
 515                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
 516         },
 517         {
 518                 .hook           = ipv4_confirm,
 519                 .pf             = NFPROTO_IPV4,
 520                 .hooknum        = NF_INET_LOCAL_IN,
 521                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
 522         },
 523 };
 524
 525 /* Fast function for those who don't want to parse /proc (and I don't
 526  * blame them).
 527  * Reversing the socket's dst/src point of view gives us the reply
 528  * mapping.
 529  */
 530 static int
 531 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
 532 {
 533         const struct inet_sock *inet = inet_sk(sk);
 534         const struct nf_conntrack_tuple_hash *h;
 535         struct nf_conntrack_tuple tuple;
 536
 537         memset(&tuple, 0, sizeof(tuple));
 538
 539         lock_sock(sk);
 540         tuple.src.u3.ip = inet->inet_rcv_saddr;
 541         tuple.src.u.tcp.port = inet->inet_sport;
 542         tuple.dst.u3.ip = inet->inet_daddr;
 543         tuple.dst.u.tcp.port = inet->inet_dport;
 544         tuple.src.l3num = PF_INET;
 545         tuple.dst.protonum = sk->sk_protocol;
 546         release_sock(sk);
 547
 548         /* We only do TCP and SCTP at the moment: is there a better way? */
 549         if (tuple.dst.protonum != IPPROTO_TCP &&
 550             tuple.dst.protonum != IPPROTO_SCTP) {
 551                 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
 552                 return -ENOPROTOOPT;
 553         }
 554
 555         if ((unsigned int)*len < sizeof(struct sockaddr_in)) {
 556                 pr_debug("SO_ORIGINAL_DST: len %d not %zu\n",
 557                          *len, sizeof(struct sockaddr_in));
 558                 return -EINVAL;
 559         }
 560
 561         h = nf_conntrack_find_get(sock_net(sk), &nf_ct_zone_dflt, &tuple);
 562         if (h) {
 563                 struct sockaddr_in sin;
 564                 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 565
 566                 sin.sin_family = AF_INET;
 567                 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
 568                         .tuple.dst.u.tcp.port;
 569                 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
 570                         .tuple.dst.u3.ip;
 571                 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
 572
 573                 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
 574                          &sin.sin_addr.s_addr, ntohs(sin.sin_port));
 575                 nf_ct_put(ct);
 576                 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
 577                         return -EFAULT;
 578                 else
 579                         return 0;
 580         }
 581         pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
 582                  &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
 583                  &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
 584         return -ENOENT;
 585 }
 586
 587 static struct nf_sockopt_ops so_getorigdst = {
 588         .pf             = PF_INET,
 589         .get_optmin     = SO_ORIGINAL_DST,
 590         .get_optmax     = SO_ORIGINAL_DST + 1,
 591         .get            = getorigdst,
 592         .owner          = THIS_MODULE,
 593 };
 594
 595 #if IS_ENABLED(CONFIG_IPV6)
 596 static int
 597 ipv6_getorigdst(struct sock *sk, int optval, void __user *user, int *len)
 598 {
 599         struct nf_conntrack_tuple tuple = { .src.l3num = NFPROTO_IPV6 };
 600         const struct ipv6_pinfo *inet6 = inet6_sk(sk);
 601         const struct inet_sock *inet = inet_sk(sk);
 602         const struct nf_conntrack_tuple_hash *h;
 603         struct sockaddr_in6 sin6;
 604         struct nf_conn *ct;
 605         __be32 flow_label;
 606         int bound_dev_if;
 607
 608         lock_sock(sk);
 609         tuple.src.u3.in6 = sk->sk_v6_rcv_saddr;
 610         tuple.src.u.tcp.port = inet->inet_sport;
 611         tuple.dst.u3.in6 = sk->sk_v6_daddr;
 612         tuple.dst.u.tcp.port = inet->inet_dport;
 613         tuple.dst.protonum = sk->sk_protocol;
 614         bound_dev_if = sk->sk_bound_dev_if;
 615         flow_label = inet6->flow_label;
 616         release_sock(sk);
 617
 618         if (tuple.dst.protonum != IPPROTO_TCP &&
 619             tuple.dst.protonum != IPPROTO_SCTP)
 620                 return -ENOPROTOOPT;
 621
 622         if (*len < 0 || (unsigned int)*len < sizeof(sin6))
 623                 return -EINVAL;
 624
 625         h = nf_conntrack_find_get(sock_net(sk), &nf_ct_zone_dflt, &tuple);
 626         if (!h) {
 627                 pr_debug("IP6T_SO_ORIGINAL_DST: Can't find %pI6c/%u-%pI6c/%u.\n",
 628                          &tuple.src.u3.ip6, ntohs(tuple.src.u.tcp.port),
 629                          &tuple.dst.u3.ip6, ntohs(tuple.dst.u.tcp.port));
 630                 return -ENOENT;
 631         }
 632
 633         ct = nf_ct_tuplehash_to_ctrack(h);
 634
 635         sin6.sin6_family = AF_INET6;
 636         sin6.sin6_port = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.tcp.port;
 637         sin6.sin6_flowinfo = flow_label & IPV6_FLOWINFO_MASK;
 638         memcpy(&sin6.sin6_addr,
 639                &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.in6,
 640                sizeof(sin6.sin6_addr));
 641
 642         nf_ct_put(ct);
 643         sin6.sin6_scope_id = ipv6_iface_scope_id(&sin6.sin6_addr, bound_dev_if);
 644         return copy_to_user(user, &sin6, sizeof(sin6)) ? -EFAULT : 0;
 645 }
 646
 647 static struct nf_sockopt_ops so_getorigdst6 = {
 648         .pf             = NFPROTO_IPV6,
 649         .get_optmin     = IP6T_SO_ORIGINAL_DST,
 650         .get_optmax     = IP6T_SO_ORIGINAL_DST + 1,
 651         .get            = ipv6_getorigdst,
 652         .owner          = THIS_MODULE,
 653 };
 654
 655 static unsigned int ipv6_confirm(void *priv,
 656                                  struct sk_buff *skb,
 657                                  const struct nf_hook_state *state)
 658 {
 659         struct nf_conn *ct;
 660         enum ip_conntrack_info ctinfo;
 661         unsigned char pnum = ipv6_hdr(skb)->nexthdr;
 662         int protoff;
 663         __be16 frag_off;
 664
 665         ct = nf_ct_get(skb, &ctinfo);
 666         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 667                 goto out;
 668
 669         protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
 670                                    &frag_off);
 671         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 672                 pr_debug("proto header not found\n");
 673                 goto out;
 674         }
 675
 676         /* adjust seqs for loopback traffic only in outgoing direction */
 677         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
 678             !nf_is_loopback_packet(skb)) {
 679                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
 680                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
 681                         return NF_DROP;
 682                 }
 683         }
 684 out:
 685         /* We've seen it coming out the other side: confirm it */
 686         return nf_conntrack_confirm(skb);
 687 }
 688
 689 static unsigned int ipv6_conntrack_in(void *priv,
 690                                       struct sk_buff *skb,
 691                                       const struct nf_hook_state *state)
 692 {
 693         return nf_conntrack_in(state->net, PF_INET6, state->hook, skb);
 694 }
 695
 696 static unsigned int ipv6_conntrack_local(void *priv,
 697                                          struct sk_buff *skb,
 698                                          const struct nf_hook_state *state)
 699 {
 700         return nf_conntrack_in(state->net, PF_INET6, state->hook, skb);
 701 }
 702
 703 static unsigned int ipv6_helper(void *priv,
 704                                 struct sk_buff *skb,
 705                                 const struct nf_hook_state *state)
 706 {
 707         struct nf_conn *ct;
 708         const struct nf_conn_help *help;
 709         const struct nf_conntrack_helper *helper;
 710         enum ip_conntrack_info ctinfo;
 711         __be16 frag_off;
 712         int protoff;
 713         u8 nexthdr;
 714
 715         /* This is where we call the helper: as the packet goes out. */
 716         ct = nf_ct_get(skb, &ctinfo);
 717         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 718                 return NF_ACCEPT;
 719
 720         help = nfct_help(ct);
 721         if (!help)
 722                 return NF_ACCEPT;
 723         /* rcu_read_lock()ed by nf_hook_thresh */
 724         helper = rcu_dereference(help->helper);
 725         if (!helper)
 726                 return NF_ACCEPT;
 727
 728         nexthdr = ipv6_hdr(skb)->nexthdr;
 729         protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
 730                                    &frag_off);
 731         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 732                 pr_debug("proto header not found\n");
 733                 return NF_ACCEPT;
 734         }
 735
 736         return helper->help(skb, protoff, ct, ctinfo);
 737 }
 738
 739 static const struct nf_hook_ops ipv6_conntrack_ops[] = {
 740         {
 741                 .hook           = ipv6_conntrack_in,
 742                 .pf             = NFPROTO_IPV6,
 743                 .hooknum        = NF_INET_PRE_ROUTING,
 744                 .priority       = NF_IP6_PRI_CONNTRACK,
 745         },
 746         {
 747                 .hook           = ipv6_conntrack_local,
 748                 .pf             = NFPROTO_IPV6,
 749                 .hooknum        = NF_INET_LOCAL_OUT,
 750                 .priority       = NF_IP6_PRI_CONNTRACK,
 751         },
 752         {
 753                 .hook           = ipv6_helper,
 754                 .pf             = NFPROTO_IPV6,
 755                 .hooknum        = NF_INET_POST_ROUTING,
 756                 .priority       = NF_IP6_PRI_CONNTRACK_HELPER,
 757         },
 758         {
 759                 .hook           = ipv6_confirm,
 760                 .pf             = NFPROTO_IPV6,
 761                 .hooknum        = NF_INET_POST_ROUTING,
 762                 .priority       = NF_IP6_PRI_LAST,
 763         },
 764         {
 765                 .hook           = ipv6_helper,
 766                 .pf             = NFPROTO_IPV6,
 767                 .hooknum        = NF_INET_LOCAL_IN,
 768                 .priority       = NF_IP6_PRI_CONNTRACK_HELPER,
 769         },
 770         {
 771                 .hook           = ipv6_confirm,
 772                 .pf             = NFPROTO_IPV6,
 773                 .hooknum        = NF_INET_LOCAL_IN,
 774                 .priority       = NF_IP6_PRI_LAST - 1,
 775         },
 776 };
 777 #endif
 778
 779 static int nf_ct_tcp_fixup(struct nf_conn *ct, void *_nfproto)
 780 {
 781         u8 nfproto = (unsigned long)_nfproto;
 782
 783         if (nf_ct_l3num(ct) != nfproto)
 784                 return 0;
 785
 786         if (nf_ct_protonum(ct) == IPPROTO_TCP &&
 787             ct->proto.tcp.state == TCP_CONNTRACK_ESTABLISHED) {
 788                 ct->proto.tcp.seen[0].td_maxwin = 0;
 789                 ct->proto.tcp.seen[1].td_maxwin = 0;
 790         }
 791
 792         return 0;
 793 }
 794
 795 static int nf_ct_netns_do_get(struct net *net, u8 nfproto)
 796 {
 797         struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
 798         bool fixup_needed = false;
 799         int err = 0;
 800
 801         mutex_lock(&nf_ct_proto_mutex);
 802
 803         switch (nfproto) {
 804         case NFPROTO_IPV4:
 805                 cnet->users4++;
 806                 if (cnet->users4 > 1)
 807                         goto out_unlock;
 808                 err = nf_defrag_ipv4_enable(net);
 809                 if (err) {
 810                         cnet->users4 = 0;
 811                         goto out_unlock;
 812                 }
 813
 814                 err = nf_register_net_hooks(net, ipv4_conntrack_ops,
 815                                             ARRAY_SIZE(ipv4_conntrack_ops));
 816                 if (err)
 817                         cnet->users4 = 0;
 818                 else
 819                         fixup_needed = true;
 820                 break;
 821 #if IS_ENABLED(CONFIG_IPV6)
 822         case NFPROTO_IPV6:
 823                 cnet->users6++;
 824                 if (cnet->users6 > 1)
 825                         goto out_unlock;
 826                 err = nf_defrag_ipv6_enable(net);
 827                 if (err < 0) {
 828                         cnet->users6 = 0;
 829                         goto out_unlock;
 830                 }
 831
 832                 err = nf_register_net_hooks(net, ipv6_conntrack_ops,
 833                                             ARRAY_SIZE(ipv6_conntrack_ops));
 834                 if (err)
 835                         cnet->users6 = 0;
 836                 else
 837                         fixup_needed = true;
 838                 break;
 839 #endif
 840         default:
 841                 err = -EPROTO;
 842                 break;
 843         }
 844  out_unlock:
 845         mutex_unlock(&nf_ct_proto_mutex);
 846
 847         if (fixup_needed)
 848                 nf_ct_iterate_cleanup_net(net, nf_ct_tcp_fixup,
 849                                           (void *)(unsigned long)nfproto, 0, 0);
 850
 851         return err;
 852 }
 853
 854 static void nf_ct_netns_do_put(struct net *net, u8 nfproto)
 855 {
 856         struct nf_conntrack_net *cnet = net_generic(net, nf_conntrack_net_id);
 857
 858         mutex_lock(&nf_ct_proto_mutex);
 859         switch (nfproto) {
 860         case NFPROTO_IPV4:
 861                 if (cnet->users4 && (--cnet->users4 == 0))
 862                         nf_unregister_net_hooks(net, ipv4_conntrack_ops,
 863                                                 ARRAY_SIZE(ipv4_conntrack_ops));
 864                 break;
 865 #if IS_ENABLED(CONFIG_IPV6)
 866         case NFPROTO_IPV6:
 867                 if (cnet->users6 && (--cnet->users6 == 0))
 868                         nf_unregister_net_hooks(net, ipv6_conntrack_ops,
 869                                                 ARRAY_SIZE(ipv6_conntrack_ops));
 870                 break;
 871 #endif
 872         }
 873
 874         mutex_unlock(&nf_ct_proto_mutex);
 875 }
 876
 877 int nf_ct_netns_get(struct net *net, u8 nfproto)
 878 {
 879         int err;
 880
 881         if (nfproto == NFPROTO_INET) {
 882                 err = nf_ct_netns_do_get(net, NFPROTO_IPV4);
 883                 if (err < 0)
 884                         goto err1;
 885                 err = nf_ct_netns_do_get(net, NFPROTO_IPV6);
 886                 if (err < 0)
 887                         goto err2;
 888         } else {
 889                 err = nf_ct_netns_do_get(net, nfproto);
 890                 if (err < 0)
 891                         goto err1;
 892         }
 893         return 0;
 894
 895 err2:
 896         nf_ct_netns_put(net, NFPROTO_IPV4);
 897 err1:
 898         return err;
 899 }
 900 EXPORT_SYMBOL_GPL(nf_ct_netns_get);
 901
 902 void nf_ct_netns_put(struct net *net, uint8_t nfproto)
 903 {
 904         if (nfproto == NFPROTO_INET) {
 905                 nf_ct_netns_do_put(net, NFPROTO_IPV4);
 906                 nf_ct_netns_do_put(net, NFPROTO_IPV6);
 907         } else {
 908                 nf_ct_netns_do_put(net, nfproto);
 909         }
 910 }
 911 EXPORT_SYMBOL_GPL(nf_ct_netns_put);
 912
 913 static const struct nf_conntrack_l4proto * const builtin_l4proto[] = {
 914         &nf_conntrack_l4proto_tcp4,
 915         &nf_conntrack_l4proto_udp4,
 916         &nf_conntrack_l4proto_icmp,
 917 #ifdef CONFIG_NF_CT_PROTO_DCCP
 918         &nf_conntrack_l4proto_dccp4,
 919 #endif
 920 #ifdef CONFIG_NF_CT_PROTO_SCTP
 921         &nf_conntrack_l4proto_sctp4,
 922 #endif
 923 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
 924         &nf_conntrack_l4proto_udplite4,
 925 #endif
 926 #if IS_ENABLED(CONFIG_IPV6)
 927         &nf_conntrack_l4proto_tcp6,
 928         &nf_conntrack_l4proto_udp6,
 929         &nf_conntrack_l4proto_icmpv6,
 930 #ifdef CONFIG_NF_CT_PROTO_DCCP
 931         &nf_conntrack_l4proto_dccp6,
 932 #endif
 933 #ifdef CONFIG_NF_CT_PROTO_SCTP
 934         &nf_conntrack_l4proto_sctp6,
 935 #endif
 936 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
 937         &nf_conntrack_l4proto_udplite6,
 938 #endif
 939 #endif /* CONFIG_IPV6 */
 940 };
 941
 942 int nf_conntrack_proto_init(void)
 943 {
 944         int ret = 0;
 945
 946         ret = nf_register_sockopt(&so_getorigdst);
 947         if (ret < 0)
 948                 return ret;
 949
 950 #if IS_ENABLED(CONFIG_IPV6)
 951         ret = nf_register_sockopt(&so_getorigdst6);
 952         if (ret < 0)
 953                 goto cleanup_sockopt;
 954 #endif
 955         ret = nf_ct_l4proto_register(builtin_l4proto,
 956                                      ARRAY_SIZE(builtin_l4proto));
 957         if (ret < 0)
 958                 goto cleanup_sockopt2;
 959
 960         return ret;
 961 cleanup_sockopt2:
 962         nf_unregister_sockopt(&so_getorigdst);
 963 #if IS_ENABLED(CONFIG_IPV6)
 964 cleanup_sockopt:
 965         nf_unregister_sockopt(&so_getorigdst6);
 966 #endif
 967         return ret;
 968 }
 969
 970 void nf_conntrack_proto_fini(void)
 971 {
 972         unsigned int i;
 973
 974         nf_unregister_sockopt(&so_getorigdst);
 975 #if IS_ENABLED(CONFIG_IPV6)
 976         nf_unregister_sockopt(&so_getorigdst6);
 977 #endif
 978         /* No need to call nf_ct_l4proto_unregister(), the register
 979          * tables are free'd here anyway.
 980          */
 981         for (i = 0; i < ARRAY_SIZE(nf_ct_protos); i++)
 982                 kfree(nf_ct_protos[i]);
 983 }
 984
 985 int nf_conntrack_proto_pernet_init(struct net *net)
 986 {
 987         int err;
 988         struct nf_proto_net *pn = nf_ct_l4proto_net(net,
 989                                         &nf_conntrack_l4proto_generic);
 990
 991         err = nf_conntrack_l4proto_generic.init_net(net,
 992                                         nf_conntrack_l4proto_generic.l3proto);
 993         if (err < 0)
 994                 return err;
 995         err = nf_ct_l4proto_register_sysctl(net,
 996                                             pn,
 997                                             &nf_conntrack_l4proto_generic);
 998         if (err < 0)
 999                 return err;
1000
1001         err = nf_ct_l4proto_pernet_register(net, builtin_l4proto,
1002                                             ARRAY_SIZE(builtin_l4proto));
1003         if (err < 0) {
1004                 nf_ct_l4proto_unregister_sysctl(net, pn,
1005                                                 &nf_conntrack_l4proto_generic);
1006                 return err;
1007         }
1008
1009         pn->users++;
1010         return 0;
1011 }
1012
1013 void nf_conntrack_proto_pernet_fini(struct net *net)
1014 {
1015         struct nf_proto_net *pn = nf_ct_l4proto_net(net,
1016                                         &nf_conntrack_l4proto_generic);
1017
1018         nf_ct_l4proto_pernet_unregister(net, builtin_l4proto,
1019                                         ARRAY_SIZE(builtin_l4proto));
1020         pn->users--;
1021         nf_ct_l4proto_unregister_sysctl(net,
1022                                         pn,
1023                                         &nf_conntrack_l4proto_generic);
1024 }
1025
1026
1027 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1028                   &nf_conntrack_htable_size, 0600);
1029
1030 MODULE_ALIAS("ip_conntrack");
1031 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
1032 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6));
1033 MODULE_LICENSE("GPL");