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 zone_chains[] = {
  34         C(ANY, FILTER, UNSPEC,        "zone_%1$s_input"),
  35         C(ANY, FILTER, UNSPEC,        "zone_%1$s_output"),
  36         C(ANY, FILTER, UNSPEC,        "zone_%1$s_forward"),
  37
  38         C(ANY, FILTER, SRC_ACCEPT,    "zone_%1$s_src_ACCEPT"),
  39         C(ANY, FILTER, SRC_REJECT,    "zone_%1$s_src_REJECT"),
  40         C(ANY, FILTER, SRC_DROP,      "zone_%1$s_src_DROP"),
  41
  42         C(ANY, FILTER, ACCEPT,        "zone_%1$s_dest_ACCEPT"),
  43         C(ANY, FILTER, REJECT,        "zone_%1$s_dest_REJECT"),
  44         C(ANY, FILTER, DROP,          "zone_%1$s_dest_DROP"),
  45
  46         C(V4,  NAT,    SNAT,          "zone_%1$s_postrouting"),
  47         C(V4,  NAT,    DNAT,          "zone_%1$s_prerouting"),
  48
  49         C(ANY, FILTER, CUSTOM_CHAINS, "input_%1$s_rule"),
  50         C(ANY, FILTER, CUSTOM_CHAINS, "output_%1$s_rule"),
  51         C(ANY, FILTER, CUSTOM_CHAINS, "forwarding_%1$s_rule"),
  52
  53         C(V4,  NAT,    CUSTOM_CHAINS, "prerouting_%1$s_rule"),
  54         C(V4,  NAT,    CUSTOM_CHAINS, "postrouting_%1$s_rule"),
  55 };
  56
  57
  58 #define R(dir1, dir2) \
  59         "zone_%1$s_" #dir1 " -m comment --comment \"user chain for %1$s " \
  60         #dir2 "\" -j " #dir2 "_%1$s_rule"
  61
  62 static const struct chain zone_rules[] = {
  63         C(ANY, FILTER, CUSTOM_CHAINS, R(input, input)),
  64         C(ANY, FILTER, CUSTOM_CHAINS, R(output, output)),
  65         C(ANY, FILTER, CUSTOM_CHAINS, R(forward, forwarding)),
  66
  67         C(V4,  NAT,    CUSTOM_CHAINS, R(prerouting, prerouting)),
  68         C(V4,  NAT,    CUSTOM_CHAINS, R(postrouting, postrouting)),
  69 };
  70
  71 const struct fw3_option fw3_zone_opts[] = {
  72         FW3_OPT("enabled",             bool,     zone,     enabled),
  73
  74         FW3_OPT("name",                string,   zone,     name),
  75         FW3_OPT("family",              family,   zone,     family),
  76
  77         FW3_LIST("network",            device,   zone,     networks),
  78         FW3_LIST("device",             device,   zone,     devices),
  79         FW3_LIST("subnet",             address,  zone,     subnets),
  80
  81         FW3_OPT("input",               target,   zone,     policy_input),
  82         FW3_OPT("forward",             target,   zone,     policy_forward),
  83         FW3_OPT("output",              target,   zone,     policy_output),
  84
  85         FW3_OPT("masq",                bool,     zone,     masq),
  86         FW3_LIST("masq_src",           address,  zone,     masq_src),
  87         FW3_LIST("masq_dest",          address,  zone,     masq_dest),
  88
  89         FW3_OPT("extra",               string,   zone,     extra_src),
  90         FW3_OPT("extra_src",           string,   zone,     extra_src),
  91         FW3_OPT("extra_dest",          string,   zone,     extra_dest),
  92
  93         FW3_OPT("conntrack",           bool,     zone,     conntrack),
  94         FW3_OPT("mtu_fix",             bool,     zone,     mtu_fix),
  95         FW3_OPT("custom_chains",       bool,     zone,     custom_chains),
  96
  97         FW3_OPT("log",                 bool,     zone,     log),
  98         FW3_OPT("log_limit",           limit,    zone,     log_limit),
  99
 100         { }
 101 };
 102
 103
 104 static bool
 105 print_chains(enum fw3_table table, enum fw3_family family,
 106              const char *fmt, const char *name, uint32_t *targets, uint32_t mask,
 107              const struct chain *chains, int n)
 108 {
 109         bool rv = false;
 110         char cn[256] = { 0 };
 111         const struct chain *c;
 112         uint32_t t = targets ? targets[family == FW3_FAMILY_V6] : 0;
 113
 114         if (mask)
 115                 t &= mask;
 116
 117         for (c = chains; n > 0; c++, n--)
 118         {
 119                 if (!fw3_is_family(c, family))
 120                         continue;
 121
 122                 if (c->table != table)
 123                         continue;
 124
 125                 if ((c->target != FW3_TARGET_UNSPEC) && !hasbit(t, c->target))
 126                         continue;
 127
 128                 snprintf(cn, sizeof(cn), c->name, name);
 129                 fw3_pr(fmt, cn);
 130
 131                 rv = true;
 132         }
 133
 134         return rv;
 135 }
 136
 137 static void
 138 check_policy(struct uci_element *e, enum fw3_target *pol, enum fw3_target def,
 139              const char *name)
 140 {
 141         if (*pol == FW3_TARGET_UNSPEC)
 142         {
 143                 warn_elem(e, "has no %s policy specified, using default", name);
 144                 *pol = def;
 145         }
 146         else if (*pol > FW3_TARGET_DROP)
 147         {
 148                 warn_elem(e, "has invalid %s policy, using default", name);
 149                 *pol = def;
 150         }
 151 }
 152
 153 static void
 154 resolve_networks(struct uci_element *e, struct fw3_zone *zone)
 155 {
 156         struct fw3_device *net, *tmp;
 157
 158         list_for_each_entry(net, &zone->networks, list)
 159         {
 160                 tmp = fw3_ubus_device(net->name);
 161
 162                 if (!tmp)
 163                 {
 164                         warn_elem(e, "cannot resolve device of network '%s'", net->name);
 165                         continue;
 166                 }
 167
 168                 list_add_tail(&tmp->list, &zone->devices);
 169         }
 170 }
 171
 172 struct fw3_zone *
 173 fw3_alloc_zone(void)
 174 {
 175         struct fw3_zone *zone;
 176
 177         zone = malloc(sizeof(*zone));
 178
 179         if (!zone)
 180                 return NULL;
 181
 182         memset(zone, 0, sizeof(*zone));
 183
 184         INIT_LIST_HEAD(&zone->networks);
 185         INIT_LIST_HEAD(&zone->devices);
 186         INIT_LIST_HEAD(&zone->subnets);
 187         INIT_LIST_HEAD(&zone->masq_src);
 188         INIT_LIST_HEAD(&zone->masq_dest);
 189
 190         zone->enabled = true;
 191         zone->custom_chains = true;
 192         zone->log_limit.rate = 10;
 193
 194         return zone;
 195 }
 196
 197 void
 198 fw3_load_zones(struct fw3_state *state, struct uci_package *p)
 199 {
 200         struct uci_section *s;
 201         struct uci_element *e;
 202         struct fw3_zone *zone;
 203         struct fw3_defaults *defs = &state->defaults;
 204
 205         INIT_LIST_HEAD(&state->zones);
 206
 207         uci_foreach_element(&p->sections, e)
 208         {
 209                 s = uci_to_section(e);
 210
 211                 if (strcmp(s->type, "zone"))
 212                         continue;
 213
 214                 zone = fw3_alloc_zone();
 215
 216                 if (!zone)
 217                         continue;
 218
 219                 fw3_parse_options(zone, fw3_zone_opts, s);
 220
 221                 if (!zone->enabled)
 222                 {
 223                         fw3_free_zone(zone);
 224                         continue;
 225                 }
 226
 227                 if (!zone->extra_dest)
 228                         zone->extra_dest = zone->extra_src;
 229
 230                 if (!defs->custom_chains && zone->custom_chains)
 231                         zone->custom_chains = false;
 232
 233                 if (!zone->name || !*zone->name)
 234                 {
 235                         warn_elem(e, "has no name - ignoring");
 236                         fw3_free_zone(zone);
 237                         continue;
 238                 }
 239
 240                 if (list_empty(&zone->networks) && list_empty(&zone->devices) &&
 241                     list_empty(&zone->subnets) && !zone->extra_src)
 242                 {
 243                         warn_elem(e, "has no device, network, subnet or extra options");
 244                 }
 245
 246                 check_policy(e, &zone->policy_input, defs->policy_input, "input");
 247                 check_policy(e, &zone->policy_output, defs->policy_output, "output");
 248                 check_policy(e, &zone->policy_forward, defs->policy_forward, "forward");
 249
 250                 resolve_networks(e, zone);
 251
 252                 if (zone->masq)
 253                 {
 254                         setbit(zone->flags[0], FW3_TARGET_SNAT);
 255                         zone->conntrack = true;
 256                 }
 257
 258                 if (zone->custom_chains)
 259                 {
 260                         setbit(zone->flags[0], FW3_TARGET_SNAT);
 261                         setbit(zone->flags[0], FW3_TARGET_DNAT);
 262                 }
 263
 264                 setbit(zone->flags[0], fw3_to_src_target(zone->policy_input));
 265                 setbit(zone->flags[0], zone->policy_output);
 266                 setbit(zone->flags[0], zone->policy_forward);
 267
 268                 setbit(zone->flags[1], fw3_to_src_target(zone->policy_input));
 269                 setbit(zone->flags[1], zone->policy_output);
 270                 setbit(zone->flags[1], zone->policy_forward);
 271
 272                 list_add_tail(&zone->list, &state->zones);
 273         }
 274 }
 275
 276
 277 static void
 278 print_zone_chain(enum fw3_table table, enum fw3_family family,
 279                  struct fw3_zone *zone, bool reload, struct fw3_state *state)
 280 {
 281         bool c, r;
 282         uint32_t custom_mask = ~0;
 283
 284         if (!fw3_is_family(zone, family))
 285                 return;
 286
 287         set(zone->flags, family, table);
 288
 289         /* Don't touch user chains on reload */
 290         if (reload)
 291                 delbit(custom_mask, FW3_TARGET_CUSTOM_CHAINS);
 292
 293         if (zone->custom_chains)
 294                 set(zone->flags, family, FW3_TARGET_CUSTOM_CHAINS);
 295
 296         if (!zone->conntrack && !state->defaults.drop_invalid)
 297                 set(zone->flags, family, FW3_TARGET_NOTRACK);
 298
 299         c = print_chains(table, family, ":%s - [0:0]\n", zone->name,
 300                          zone->flags, custom_mask,
 301                          zone_chains, ARRAY_SIZE(zone_chains));
 302
 303         r = print_chains(table, family, "-A %s\n", zone->name,
 304                          zone->flags, 0,
 305                          zone_rules, ARRAY_SIZE(zone_rules));
 306
 307         if (c || r)
 308         {
 309                 info("   * Zone '%s'", zone->name);
 310                 fw3_set_running(zone, &state->running_zones);
 311
 312                 set(zone->flags, family, table);
 313         }
 314 }
 315
 316 static void
 317 print_interface_rule(enum fw3_table table, enum fw3_family family,
 318                      struct fw3_zone *zone, struct fw3_device *dev,
 319                      struct fw3_address *sub, bool reload, bool disable_notrack)
 320 {
 321         enum fw3_target t;
 322
 323 #define jump_target(t) \
 324         ((t == FW3_TARGET_REJECT) ? "reject" : fw3_flag_names[t])
 325
 326         if (table == FW3_TABLE_FILTER)
 327         {
 328                 for (t = FW3_TARGET_ACCEPT; t <= FW3_TARGET_DROP; t++)
 329                 {
 330                         if (has(zone->flags, family, fw3_to_src_target(t)))
 331                         {
 332                                 fw3_pr("-A zone_%s_src_%s", zone->name, fw3_flag_names[t]);
 333                                 fw3_format_in_out(dev, NULL);
 334                                 fw3_format_src_dest(sub, NULL);
 335                                 fw3_format_extra(zone->extra_src);
 336                                 fw3_pr(" -j %s\n", jump_target(t));
 337                         }
 338
 339                         if (has(zone->flags, family, t))
 340                         {
 341                                 fw3_pr("-A zone_%s_dest_%s", zone->name, fw3_flag_names[t]);
 342                                 fw3_format_in_out(NULL, dev);
 343                                 fw3_format_src_dest(NULL, sub);
 344                                 fw3_format_extra(zone->extra_dest);
 345                                 fw3_pr(" -j %s\n", jump_target(t));
 346                         }
 347                 }
 348
 349                 fw3_pr("-A delegate_input");
 350                 fw3_format_in_out(dev, NULL);
 351                 fw3_format_src_dest(sub, NULL);
 352                 fw3_format_extra(zone->extra_src);
 353                 fw3_pr(" -j zone_%s_input\n", zone->name);
 354
 355                 fw3_pr("-A delegate_forward");
 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_forward\n", zone->name);
 360
 361                 fw3_pr("-A delegate_output");
 362                 fw3_format_in_out(NULL, dev);
 363                 fw3_format_src_dest(NULL, sub);
 364                 fw3_format_extra(zone->extra_dest);
 365                 fw3_pr(" -j zone_%s_output\n", zone->name);
 366         }
 367         else if (table == FW3_TABLE_NAT)
 368         {
 369                 if (has(zone->flags, family, FW3_TARGET_DNAT))
 370                 {
 371                         fw3_pr("-A delegate_prerouting");
 372                         fw3_format_in_out(dev, NULL);
 373                         fw3_format_src_dest(sub, NULL);
 374                         fw3_format_extra(zone->extra_src);
 375                         fw3_pr(" -j zone_%s_prerouting\n", zone->name);
 376                 }
 377
 378                 if (has(zone->flags, family, FW3_TARGET_SNAT))
 379                 {
 380                         fw3_pr("-A delegate_postrouting");
 381                         fw3_format_in_out(NULL, dev);
 382                         fw3_format_src_dest(NULL, sub);
 383                         fw3_format_extra(zone->extra_dest);
 384                         fw3_pr(" -j zone_%s_postrouting\n", zone->name);
 385                 }
 386         }
 387         else if (table == FW3_TABLE_MANGLE)
 388         {
 389                 if (zone->mtu_fix)
 390                 {
 391                         if (zone->log)
 392                         {
 393                                 fw3_pr("-A mssfix");
 394                                 fw3_format_in_out(NULL, dev);
 395                                 fw3_format_src_dest(NULL, sub);
 396                                 fw3_pr(" -p tcp --tcp-flags SYN,RST SYN");
 397                                 fw3_format_limit(&zone->log_limit);
 398                                 fw3_format_comment(zone->name, " (mtu_fix logging)");
 399                                 fw3_pr(" -j LOG --log-prefix \"MSSFIX(%s): \"\n", zone->name);
 400                         }
 401
 402                         fw3_pr("-A mssfix");
 403                         fw3_format_in_out(NULL, dev);
 404                         fw3_format_src_dest(NULL, sub);
 405                         fw3_pr(" -p tcp --tcp-flags SYN,RST SYN");
 406                         fw3_format_comment(zone->name, " (mtu_fix)");
 407                         fw3_pr(" -j TCPMSS --clamp-mss-to-pmtu\n");
 408                 }
 409         }
 410         else if (table == FW3_TABLE_RAW)
 411         {
 412                 if (!zone->conntrack && !disable_notrack)
 413                 {
 414                         fw3_pr("-A notrack");
 415                         fw3_format_in_out(dev, NULL);
 416                         fw3_format_src_dest(sub, NULL);
 417                         fw3_format_extra(zone->extra_src);
 418                         fw3_format_comment(zone->name, " (notrack)");
 419                         fw3_pr(" -j CT --notrack\n", zone->name);
 420                 }
 421         }
 422 }
 423
 424 static void
 425 print_interface_rules(enum fw3_table table, enum fw3_family family,
 426                       struct fw3_zone *zone, bool reload, bool disable_notrack)
 427 {
 428         struct fw3_device *dev;
 429         struct fw3_address *sub;
 430
 431         fw3_foreach(dev, &zone->devices)
 432         fw3_foreach(sub, &zone->subnets)
 433         {
 434                 if (!fw3_is_family(sub, family))
 435                         continue;
 436
 437                 if (!dev && !sub)
 438                         continue;
 439
 440                 print_interface_rule(table, family, zone, dev, sub, reload, disable_notrack);
 441         }
 442 }
 443
 444 static void
 445 print_zone_rule(enum fw3_table table, enum fw3_family family,
 446                 struct fw3_zone *zone, bool reload, bool disable_notrack)
 447 {
 448         struct fw3_address *msrc;
 449         struct fw3_address *mdest;
 450
 451         enum fw3_target t;
 452
 453         if (!fw3_is_family(zone, family))
 454                 return;
 455
 456         switch (table)
 457         {
 458         case FW3_TABLE_FILTER:
 459                 fw3_pr("-A zone_%s_input -j zone_%s_src_%s\n",
 460                            zone->name, zone->name, fw3_flag_names[zone->policy_input]);
 461
 462                 fw3_pr("-A zone_%s_forward -j zone_%s_dest_%s\n",
 463                            zone->name, zone->name, fw3_flag_names[zone->policy_forward]);
 464
 465                 fw3_pr("-A zone_%s_output -j zone_%s_dest_%s\n",
 466                            zone->name, zone->name, fw3_flag_names[zone->policy_output]);
 467
 468                 if (zone->log)
 469                 {
 470                         for (t = FW3_TARGET_REJECT; t <= FW3_TARGET_DROP; t++)
 471                         {
 472                                 if (has(zone->flags, family, fw3_to_src_target(t)))
 473                                 {
 474                                         fw3_pr("-A zone_%s_src_%s", zone->name, fw3_flag_names[t]);
 475                                         fw3_format_limit(&zone->log_limit);
 476                                         fw3_pr(" -j LOG --log-prefix \"%s(src %s)\"\n",
 477                                                    fw3_flag_names[t], zone->name);
 478                                 }
 479
 480                                 if (has(zone->flags, family, t))
 481                                 {
 482                                         fw3_pr("-A zone_%s_dest_%s", zone->name, fw3_flag_names[t]);
 483                                         fw3_format_limit(&zone->log_limit);
 484                                         fw3_pr(" -j LOG --log-prefix \"%s(dest %s)\"\n",
 485                                                    fw3_flag_names[t], zone->name);
 486                                 }
 487                         }
 488                 }
 489                 break;
 490
 491         case FW3_TABLE_NAT:
 492                 if (zone->masq && family == FW3_FAMILY_V4)
 493                 {
 494                         fw3_foreach(msrc, &zone->masq_src)
 495                         fw3_foreach(mdest, &zone->masq_dest)
 496                         {
 497                                 fw3_pr("-A zone_%s_postrouting ", zone->name);
 498                                 fw3_format_src_dest(msrc, mdest);
 499                                 fw3_pr("-j MASQUERADE\n");
 500                         }
 501                 }
 502                 break;
 503
 504         case FW3_TABLE_RAW:
 505         case FW3_TABLE_MANGLE:
 506                 break;
 507         }
 508
 509         print_interface_rules(table, family, zone, reload, disable_notrack);
 510 }
 511
 512 void
 513 fw3_print_zone_chains(enum fw3_table table, enum fw3_family family,
 514                       bool reload, struct fw3_state *state)
 515 {
 516         struct fw3_zone *zone;
 517
 518         list_for_each_entry(zone, &state->zones, list)
 519                 print_zone_chain(table, family, zone, reload, state);
 520 }
 521
 522 void
 523 fw3_print_zone_rules(enum fw3_table table, enum fw3_family family,
 524                      bool reload, struct fw3_state *state)
 525 {
 526         struct fw3_zone *zone;
 527
 528         list_for_each_entry(zone, &state->zones, list)
 529                 print_zone_rule(table, family, zone, reload, state->defaults.drop_invalid);
 530 }
 531
 532 void
 533 fw3_flush_zones(enum fw3_table table, enum fw3_family family,
 534                             bool pass2, bool reload, struct fw3_state *state)
 535 {
 536         struct fw3_zone *z, *tmp;
 537         uint32_t custom_mask = ~0;
 538
 539         /* don't touch user chains on selective stop */
 540         if (reload)
 541                 delbit(custom_mask, FW3_TARGET_CUSTOM_CHAINS);
 542
 543         list_for_each_entry_safe(z, tmp, &state->running_zones, running_list)
 544         {
 545                 if (!has(z->flags, family, table))
 546                         continue;
 547
 548                 print_chains(table, family, pass2 ? "-X %s\n" : "-F %s\n",
 549                              z->name, z->flags, custom_mask,
 550                              zone_chains, ARRAY_SIZE(zone_chains));
 551
 552                 if (pass2)
 553                 {
 554                         del(z->flags, family, table);
 555                 }
 556         }
 557 }
 558
 559 struct fw3_zone *
 560 fw3_lookup_zone(struct fw3_state *state, const char *name, bool running)
 561 {
 562         struct fw3_zone *z;
 563
 564         if (list_empty(&state->zones))
 565                 return NULL;
 566
 567         list_for_each_entry(z, &state->zones, list)
 568         {
 569                 if (strcmp(z->name, name))
 570                         continue;
 571
 572                 if (!running || z->running_list.next)
 573                         return z;
 574
 575                 break;
 576         }
 577
 578         return NULL;
 579 }