zones.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "zones.h"
  20 #include "ubus.h"
  21
  22
  23 #define C(f, tbl, tgt, name) \
  24         { FW3_FAMILY_##f, FW3_TABLE_##tbl, FW3_TARGET_##tgt, name }
  25
  26 struct chain {
  27         enum fw3_family family;
  28         enum fw3_table table;
  29         enum fw3_target target;
  30         const char *name;
  31 };
  32
  33 static const struct chain src_chains[] = {
  34         C(ANY, FILTER, UNSPEC,  "zone_%s_input"),
  35         C(ANY, FILTER, UNSPEC,  "zone_%s_output"),
  36         C(ANY, FILTER, UNSPEC,  "zone_%s_forward"),
  37
  38         C(ANY, FILTER, ACCEPT,  "zone_%s_src_ACCEPT"),
  39         C(ANY, FILTER, REJECT,  "zone_%s_src_REJECT"),
  40         C(ANY, FILTER, DROP,    "zone_%s_src_DROP"),
  41 };
  42
  43 static const struct chain dst_chains[] = {
  44         C(ANY, FILTER, ACCEPT,  "zone_%s_dest_ACCEPT"),
  45         C(ANY, FILTER, REJECT,  "zone_%s_dest_REJECT"),
  46         C(ANY, FILTER, DROP,    "zone_%s_dest_DROP"),
  47
  48         C(V4,  NAT,    SNAT,    "zone_%s_postrouting"),
  49         C(V4,  NAT,    DNAT,    "zone_%s_prerouting"),
  50
  51         C(ANY, FILTER, CUSTOM_CHAINS, "input_%s_rule"),
  52         C(ANY, FILTER, CUSTOM_CHAINS, "output_%s_rule"),
  53         C(ANY, FILTER, CUSTOM_CHAINS, "forwarding_%s_rule"),
  54
  55         C(V4,  NAT,    CUSTOM_CHAINS, "prerouting_%s_rule"),
  56         C(V4,  NAT,    CUSTOM_CHAINS, "postrouting_%s_rule"),
  57 };
  58
  59 const struct fw3_option fw3_zone_opts[] = {
  60         FW3_OPT("enabled",             bool,     zone,     enabled),
  61
  62         FW3_OPT("name",                string,   zone,     name),
  63         FW3_OPT("family",              family,   zone,     family),
  64
  65         FW3_LIST("network",            device,   zone,     networks),
  66         FW3_LIST("device",             device,   zone,     devices),
  67         FW3_LIST("subnet",             address,  zone,     subnets),
  68
  69         FW3_OPT("input",               target,   zone,     policy_input),
  70         FW3_OPT("forward",             target,   zone,     policy_forward),
  71         FW3_OPT("output",              target,   zone,     policy_output),
  72
  73         FW3_OPT("masq",                bool,     zone,     masq),
  74         FW3_LIST("masq_src",           address,  zone,     masq_src),
  75         FW3_LIST("masq_dest",          address,  zone,     masq_dest),
  76
  77         FW3_OPT("extra",               string,   zone,     extra_src),
  78         FW3_OPT("extra_src",           string,   zone,     extra_src),
  79         FW3_OPT("extra_dest",          string,   zone,     extra_dest),
  80
  81         FW3_OPT("conntrack",           bool,     zone,     conntrack),
  82         FW3_OPT("mtu_fix",             bool,     zone,     mtu_fix),
  83         FW3_OPT("custom_chains",       bool,     zone,     custom_chains),
  84
  85         FW3_OPT("log",                 bool,     zone,     log),
  86         FW3_OPT("log_limit",           limit,    zone,     log_limit),
  87
  88         { }
  89 };
  90
  91
  92 static bool
  93 print_chains(enum fw3_table table, enum fw3_family family,
  94              const char *fmt, const char *name, uint16_t targets,
  95              const struct chain *chains, int n)
  96 {
  97         bool rv = false;
  98         char cn[128] = { 0 };
  99         const struct chain *c;
 100
 101         for (c = chains; n > 0; c++, n--)
 102         {
 103                 if (!fw3_is_family(c, family))
 104                         continue;
 105
 106                 if (c->table != table)
 107                         continue;
 108
 109                 if ((c->target != FW3_TARGET_UNSPEC) && !hasbit(targets, c->target))
 110                         continue;
 111
 112                 snprintf(cn, sizeof(cn), c->name, name);
 113                 fw3_pr(fmt, cn);
 114
 115                 rv = true;
 116         }
 117
 118         return rv;
 119 }
 120
 121 static void
 122 check_policy(struct uci_element *e, enum fw3_target *pol, enum fw3_target def,
 123              const char *name)
 124 {
 125         if (*pol == FW3_TARGET_UNSPEC)
 126         {
 127                 warn_elem(e, "has no %s policy specified, using default", name);
 128                 *pol = def;
 129         }
 130         else if (*pol > FW3_TARGET_DROP)
 131         {
 132                 warn_elem(e, "has invalid %s policy, using default", name);
 133                 *pol = def;
 134         }
 135 }
 136
 137 static void
 138 resolve_networks(struct uci_element *e, struct fw3_zone *zone)
 139 {
 140         struct fw3_device *net, *tmp;
 141
 142         list_for_each_entry(net, &zone->networks, list)
 143         {
 144                 tmp = fw3_ubus_device(net->name);
 145
 146                 if (!tmp)
 147                 {
 148                         warn_elem(e, "cannot resolve device of network '%s'", net->name);
 149                         continue;
 150                 }
 151
 152                 list_add_tail(&tmp->list, &zone->devices);
 153         }
 154 }
 155
 156 struct fw3_zone *
 157 fw3_alloc_zone(void)
 158 {
 159         struct fw3_zone *zone;
 160
 161         zone = malloc(sizeof(*zone));
 162
 163         if (!zone)
 164                 return NULL;
 165
 166         memset(zone, 0, sizeof(*zone));
 167
 168         INIT_LIST_HEAD(&zone->networks);
 169         INIT_LIST_HEAD(&zone->devices);
 170         INIT_LIST_HEAD(&zone->subnets);
 171         INIT_LIST_HEAD(&zone->masq_src);
 172         INIT_LIST_HEAD(&zone->masq_dest);
 173
 174         zone->enabled = true;
 175         zone->custom_chains = true;
 176         zone->log_limit.rate = 10;
 177
 178         return zone;
 179 }
 180
 181 void
 182 fw3_load_zones(struct fw3_state *state, struct uci_package *p)
 183 {
 184         struct uci_section *s;
 185         struct uci_element *e;
 186         struct fw3_zone *zone;
 187         struct fw3_defaults *defs = &state->defaults;
 188
 189         INIT_LIST_HEAD(&state->zones);
 190
 191         uci_foreach_element(&p->sections, e)
 192         {
 193                 s = uci_to_section(e);
 194
 195                 if (strcmp(s->type, "zone"))
 196                         continue;
 197
 198                 zone = fw3_alloc_zone();
 199
 200                 if (!zone)
 201                         continue;
 202
 203                 fw3_parse_options(zone, fw3_zone_opts, s);
 204
 205                 if (!zone->enabled)
 206                 {
 207                         fw3_free_zone(zone);
 208                         continue;
 209                 }
 210
 211                 if (!zone->extra_dest)
 212                         zone->extra_dest = zone->extra_src;
 213
 214                 if (!defs->custom_chains && zone->custom_chains)
 215                         zone->custom_chains = false;
 216
 217                 if (!zone->name || !*zone->name)
 218                 {
 219                         warn_elem(e, "has no name - ignoring");
 220                         fw3_free_zone(zone);
 221                         continue;
 222                 }
 223
 224                 if (list_empty(&zone->networks) && list_empty(&zone->devices) &&
 225                     list_empty(&zone->subnets) && !zone->extra_src)
 226                 {
 227                         warn_elem(e, "has no device, network, subnet or extra options");
 228                 }
 229
 230                 check_policy(e, &zone->policy_input, defs->policy_input, "input");
 231                 check_policy(e, &zone->policy_output, defs->policy_output, "output");
 232                 check_policy(e, &zone->policy_forward, defs->policy_forward, "forward");
 233
 234                 resolve_networks(e, zone);
 235
 236                 if (zone->masq)
 237                 {
 238                         setbit(zone->dst_flags, FW3_TARGET_SNAT);
 239                         zone->conntrack = true;
 240                 }
 241
 242                 if (zone->custom_chains)
 243                 {
 244                         setbit(zone->dst_flags, FW3_TARGET_SNAT);
 245                         setbit(zone->dst_flags, FW3_TARGET_DNAT);
 246                 }
 247
 248                 setbit(zone->src_flags, zone->policy_input);
 249                 setbit(zone->dst_flags, zone->policy_output);
 250                 setbit(zone->dst_flags, zone->policy_forward);
 251
 252                 list_add_tail(&zone->list, &state->zones);
 253         }
 254 }
 255
 256
 257 static void
 258 print_zone_chain(enum fw3_table table, enum fw3_family family,
 259                  struct fw3_zone *zone, struct fw3_state *state)
 260 {
 261         bool s, d;
 262         uint16_t mask = ~0;
 263
 264         if (!fw3_is_family(zone, family))
 265                 return;
 266
 267         setbit(zone->dst_flags, family);
 268
 269         /* user chains already loaded, don't create again */
 270         if (hasbit(zone->dst_flags, FW3_TARGET_CUSTOM_CHAINS))
 271                 delbit(mask, FW3_TARGET_CUSTOM_CHAINS);
 272
 273         if (zone->custom_chains)
 274                 setbit(zone->dst_flags, FW3_TARGET_CUSTOM_CHAINS);
 275
 276         if (!zone->conntrack && !state->defaults.drop_invalid)
 277                 setbit(zone->dst_flags, FW3_TARGET_NOTRACK);
 278
 279         s = print_chains(table, family, ":%s - [0:0]\n", zone->name,
 280                          zone->src_flags & mask,
 281                          src_chains, ARRAY_SIZE(src_chains));
 282
 283         d = print_chains(table, family, ":%s - [0:0]\n", zone->name,
 284                          zone->dst_flags & mask,
 285                          dst_chains, ARRAY_SIZE(dst_chains));
 286
 287         if (zone->custom_chains)
 288         {
 289                 if (table == FW3_TABLE_FILTER)
 290                 {
 291                         fw3_pr("-A zone_%s_input -j input_%s_rule "
 292                                    "-m comment --comment \"user chain for %s input\"\n",
 293                                zone->name, zone->name, zone->name);
 294
 295                         fw3_pr("-A zone_%s_output -j output_%s_rule "
 296                                    "-m comment --comment \"user chain for %s output\"\n",
 297                                zone->name, zone->name, zone->name);
 298
 299                         fw3_pr("-A zone_%s_forward -j forwarding_%s_rule "
 300                                    "-m comment --comment \"user chain for %s forwarding\"\n",
 301                                zone->name, zone->name, zone->name);
 302                 }
 303                 else if (table == FW3_TABLE_NAT)
 304                 {
 305                         fw3_pr("-A zone_%s_prerouting -j prerouting_%s_rule "
 306                                "-m comment --comment \"user chain for %s prerouting\"\n",
 307                                zone->name, zone->name, zone->name);
 308
 309                         fw3_pr("-A zone_%s_postrouting -j postrouting_%s_rule "
 310                                "-m comment --comment \"user chain for %s postrouting\"\n",
 311                                zone->name, zone->name, zone->name);
 312                 }
 313         }
 314
 315         if (s || d)
 316         {
 317                 info("   * Zone '%s'", zone->name);
 318                 fw3_set_running(zone, &state->running_zones);
 319         }
 320 }
 321
 322 static void
 323 print_interface_rule(enum fw3_table table, enum fw3_family family,
 324                      struct fw3_zone *zone, struct fw3_device *dev,
 325                      struct fw3_address *sub, bool disable_notrack)
 326 {
 327         enum fw3_target t;
 328
 329 #define jump_target(t) \
 330         ((t == FW3_TARGET_REJECT) ? "reject" : fw3_flag_names[t])
 331
 332         if (table == FW3_TABLE_FILTER)
 333         {
 334                 for (t = FW3_TARGET_ACCEPT; t <= FW3_TARGET_DROP; t++)
 335                 {
 336                         if (hasbit(zone->src_flags, t))
 337                         {
 338                                 fw3_pr("-A zone_%s_src_%s", zone->name, fw3_flag_names[t]);
 339                                 fw3_format_in_out(dev, NULL);
 340                                 fw3_format_src_dest(sub, NULL);
 341                                 fw3_format_extra(zone->extra_src);
 342                                 fw3_pr(" -j %s\n", jump_target(t));
 343                         }
 344
 345                         if (hasbit(zone->dst_flags, t))
 346                         {
 347                                 fw3_pr("-A zone_%s_dest_%s", zone->name, fw3_flag_names[t]);
 348                                 fw3_format_in_out(NULL, dev);
 349                                 fw3_format_src_dest(NULL, sub);
 350                                 fw3_format_extra(zone->extra_dest);
 351                                 fw3_pr(" -j %s\n", jump_target(t));
 352                         }
 353                 }
 354
 355                 fw3_pr("-A delegate_input");
 356                 fw3_format_in_out(dev, NULL);
 357                 fw3_format_src_dest(sub, NULL);
 358                 fw3_format_extra(zone->extra_src);
 359                 fw3_pr(" -j zone_%s_input\n", zone->name);
 360
 361                 fw3_pr("-A delegate_forward");
 362                 fw3_format_in_out(dev, NULL);
 363                 fw3_format_src_dest(sub, NULL);
 364                 fw3_format_extra(zone->extra_src);
 365                 fw3_pr(" -j zone_%s_forward\n", zone->name);
 366
 367                 fw3_pr("-A delegate_output");
 368                 fw3_format_in_out(NULL, dev);
 369                 fw3_format_src_dest(NULL, sub);
 370                 fw3_format_extra(zone->extra_dest);
 371                 fw3_pr(" -j zone_%s_output\n", zone->name);
 372         }
 373         else if (table == FW3_TABLE_NAT)
 374         {
 375                 if (hasbit(zone->dst_flags, FW3_TARGET_DNAT))
 376                 {
 377                         fw3_pr("-A delegate_prerouting");
 378                         fw3_format_in_out(dev, NULL);
 379                         fw3_format_src_dest(sub, NULL);
 380                         fw3_format_extra(zone->extra_src);
 381                         fw3_pr(" -j zone_%s_prerouting\n", zone->name);
 382                 }
 383
 384                 if (hasbit(zone->dst_flags, FW3_TARGET_SNAT))
 385                 {
 386                         fw3_pr("-A delegate_postrouting");
 387                         fw3_format_in_out(NULL, dev);
 388                         fw3_format_src_dest(NULL, sub);
 389                         fw3_format_extra(zone->extra_dest);
 390                         fw3_pr(" -j zone_%s_postrouting\n", zone->name);
 391                 }
 392         }
 393         else if (table == FW3_TABLE_MANGLE)
 394         {
 395                 if (zone->mtu_fix)
 396                 {
 397                         if (zone->log)
 398                         {
 399                                 fw3_pr("-A mssfix");
 400                                 fw3_format_in_out(NULL, dev);
 401                                 fw3_format_src_dest(NULL, sub);
 402                                 fw3_pr(" -p tcp --tcp-flags SYN,RST SYN");
 403                                 fw3_format_limit(&zone->log_limit);
 404                                 fw3_format_comment(zone->name, " (mtu_fix logging)");
 405                                 fw3_pr(" -j LOG --log-prefix \"MSSFIX(%s): \"\n", zone->name);
 406                         }
 407
 408                         fw3_pr("-A mssfix");
 409                         fw3_format_in_out(NULL, dev);
 410                         fw3_format_src_dest(NULL, sub);
 411                         fw3_pr(" -p tcp --tcp-flags SYN,RST SYN");
 412                         fw3_format_comment(zone->name, " (mtu_fix)");
 413                         fw3_pr(" -j TCPMSS --clamp-mss-to-pmtu\n");
 414                 }
 415         }
 416         else if (table == FW3_TABLE_RAW)
 417         {
 418                 if (!zone->conntrack && !disable_notrack)
 419                 {
 420                         fw3_pr("-A notrack");
 421                         fw3_format_in_out(dev, NULL);
 422                         fw3_format_src_dest(sub, NULL);
 423                         fw3_format_extra(zone->extra_src);
 424                         fw3_format_comment(zone->name, " (notrack)");
 425                         fw3_pr(" -j CT --notrack\n", zone->name);
 426                 }
 427         }
 428 }
 429
 430 static void
 431 print_interface_rules(enum fw3_table table, enum fw3_family family,
 432                       struct fw3_zone *zone, bool disable_notrack)
 433 {
 434         struct fw3_device *dev;
 435         struct fw3_address *sub;
 436
 437         fw3_foreach(dev, &zone->devices)
 438         fw3_foreach(sub, &zone->subnets)
 439         {
 440                 if (!fw3_is_family(sub, family))
 441                         continue;
 442
 443                 if (!dev && !sub)
 444                         continue;
 445
 446                 print_interface_rule(table, family, zone, dev, sub, disable_notrack);
 447         }
 448 }
 449
 450 static void
 451 print_zone_rule(enum fw3_table table, enum fw3_family family,
 452                 struct fw3_zone *zone, bool disable_notrack)
 453 {
 454         struct fw3_address *msrc;
 455         struct fw3_address *mdest;
 456
 457         enum fw3_target t;
 458
 459         if (!fw3_is_family(zone, family))
 460                 return;
 461
 462         switch (table)
 463         {
 464         case FW3_TABLE_FILTER:
 465                 fw3_pr("-A zone_%s_input -j zone_%s_src_%s\n",
 466                            zone->name, zone->name, fw3_flag_names[zone->policy_input]);
 467
 468                 fw3_pr("-A zone_%s_forward -j zone_%s_dest_%s\n",
 469                            zone->name, zone->name, fw3_flag_names[zone->policy_forward]);
 470
 471                 fw3_pr("-A zone_%s_output -j zone_%s_dest_%s\n",
 472                            zone->name, zone->name, fw3_flag_names[zone->policy_output]);
 473
 474                 if (zone->log)
 475                 {
 476                         for (t = FW3_TARGET_REJECT; t <= FW3_TARGET_DROP; t++)
 477                         {
 478                                 if (hasbit(zone->src_flags, t))
 479                                 {
 480                                         fw3_pr("-A zone_%s_src_%s", zone->name, fw3_flag_names[t]);
 481                                         fw3_format_limit(&zone->log_limit);
 482                                         fw3_pr(" -j LOG --log-prefix \"%s(src %s)\"\n",
 483                                                    fw3_flag_names[t], zone->name);
 484                                 }
 485
 486                                 if (hasbit(zone->dst_flags, t))
 487                                 {
 488                                         fw3_pr("-A zone_%s_dest_%s", zone->name, fw3_flag_names[t]);
 489                                         fw3_format_limit(&zone->log_limit);
 490                                         fw3_pr(" -j LOG --log-prefix \"%s(dest %s)\"\n",
 491                                                    fw3_flag_names[t], zone->name);
 492                                 }
 493                         }
 494                 }
 495                 break;
 496
 497         case FW3_TABLE_NAT:
 498                 if (zone->masq && family == FW3_FAMILY_V4)
 499                 {
 500                         fw3_foreach(msrc, &zone->masq_src)
 501                         fw3_foreach(mdest, &zone->masq_dest)
 502                         {
 503                                 fw3_pr("-A zone_%s_postrouting ", zone->name);
 504                                 fw3_format_src_dest(msrc, mdest);
 505                                 fw3_pr("-j MASQUERADE\n");
 506                         }
 507                 }
 508                 break;
 509
 510         case FW3_TABLE_RAW:
 511         case FW3_TABLE_MANGLE:
 512                 break;
 513         }
 514
 515         print_interface_rules(table, family, zone, disable_notrack);
 516 }
 517
 518 void
 519 fw3_print_zone_chains(enum fw3_table table, enum fw3_family family,
 520                       struct fw3_state *state)
 521 {
 522         struct fw3_zone *zone;
 523
 524         list_for_each_entry(zone, &state->zones, list)
 525                 print_zone_chain(table, family, zone, state);
 526 }
 527
 528 void
 529 fw3_print_zone_rules(enum fw3_table table, enum fw3_family family,
 530                      struct fw3_state *state)
 531 {
 532         struct fw3_zone *zone;
 533
 534         list_for_each_entry(zone, &state->zones, list)
 535                 print_zone_rule(table, family, zone, state->defaults.drop_invalid);
 536 }
 537
 538 void
 539 fw3_flush_zones(enum fw3_table table, enum fw3_family family,
 540                             bool pass2, bool reload, struct fw3_state *state)
 541 {
 542         struct fw3_zone *z, *tmp;
 543         uint16_t mask = ~0;
 544         uint16_t families = (1 << FW3_FAMILY_V4) | (1 << FW3_FAMILY_V6);
 545
 546         /* don't touch user chains on selective stop */
 547         if (reload)
 548                 delbit(mask, FW3_DEFAULT_CUSTOM_CHAINS);
 549
 550         list_for_each_entry_safe(z, tmp, &state->running_zones, running_list)
 551         {
 552                 if (!hasbit(z->dst_flags, family))
 553                         continue;
 554
 555                 print_chains(table, family, pass2 ? "-X %s\n" : "-F %s\n",
 556                              z->name, z->src_flags & mask,
 557                              src_chains, ARRAY_SIZE(src_chains));
 558
 559                 print_chains(table, family, pass2 ? "-X %s\n" : "-F %s\n",
 560                              z->name, z->dst_flags & mask,
 561                              dst_chains, ARRAY_SIZE(dst_chains));
 562
 563                 if (pass2)
 564                 {
 565                         delbit(z->dst_flags, family);
 566
 567                         if (!(z->dst_flags & families))
 568                                 fw3_set_running(z, NULL);
 569                 }
 570         }
 571 }
 572
 573 struct fw3_zone *
 574 fw3_lookup_zone(struct fw3_state *state, const char *name, bool running)
 575 {
 576         struct fw3_zone *z;
 577
 578         if (list_empty(&state->zones))
 579                 return NULL;
 580
 581         list_for_each_entry(z, &state->zones, list)
 582         {
 583                 if (strcmp(z->name, name))
 584                         continue;
 585
 586                 if (!running || z->running_list.next)
 587                         return z;
 588
 589                 break;
 590         }
 591
 592         return NULL;
 593 }