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_%1$s_input"),
  35         C(ANY, FILTER, UNSPEC,  "zone_%1$s_output"),
  36         C(ANY, FILTER, UNSPEC,  "zone_%1$s_forward"),
  37
  38         C(ANY, FILTER, ACCEPT,  "zone_%1$s_src_ACCEPT"),
  39         C(ANY, FILTER, REJECT,  "zone_%1$s_src_REJECT"),
  40         C(ANY, FILTER, DROP,    "zone_%1$s_src_DROP"),
  41 };
  42
  43 static const struct chain dst_chains[] = {
  44         C(ANY, FILTER, ACCEPT,  "zone_%1$s_dest_ACCEPT"),
  45         C(ANY, FILTER, REJECT,  "zone_%1$s_dest_REJECT"),
  46         C(ANY, FILTER, DROP,    "zone_%1$s_dest_DROP"),
  47
  48         C(V4,  NAT,    SNAT,    "zone_%1$s_postrouting"),
  49         C(V4,  NAT,    DNAT,    "zone_%1$s_prerouting"),
  50
  51         C(ANY, FILTER, CUSTOM_CNS_V4, "input_%1$s_rule"),
  52         C(ANY, FILTER, CUSTOM_CNS_V4, "output_%1$s_rule"),
  53         C(ANY, FILTER, CUSTOM_CNS_V4, "forwarding_%1$s_rule"),
  54         C(ANY, FILTER, CUSTOM_CNS_V6, "input_%1$s_rule"),
  55         C(ANY, FILTER, CUSTOM_CNS_V6, "output_%1$s_rule"),
  56         C(ANY, FILTER, CUSTOM_CNS_V6, "forwarding_%1$s_rule"),
  57
  58         C(V4,  NAT,    CUSTOM_CNS_V4, "prerouting_%1$s_rule"),
  59         C(V4,  NAT,    CUSTOM_CNS_V4, "postrouting_%1$s_rule"),
  60 };
  61
  62
  63 #define R(dir1, dir2) \
  64         "zone_%1$s_" #dir1 " -m comment --comment \"user chain for %1$s " \
  65         #dir2 "\" -j " #dir2 "_%1$s_rule"
  66
  67 static const struct chain def_rules[] = {
  68         C(ANY, FILTER, CUSTOM_CNS_V4, R(input, input)),
  69         C(ANY, FILTER, CUSTOM_CNS_V4, R(output, output)),
  70         C(ANY, FILTER, CUSTOM_CNS_V4, R(forward, forwarding)),
  71         C(ANY, FILTER, CUSTOM_CNS_V6, R(input, input)),
  72         C(ANY, FILTER, CUSTOM_CNS_V6, R(output, output)),
  73         C(ANY, FILTER, CUSTOM_CNS_V6, R(forward, forwarding)),
  74
  75         C(V4,  NAT,    CUSTOM_CNS_V4, R(prerouting, prerouting)),
  76         C(V4,  NAT,    CUSTOM_CNS_V4, R(postrouting, postrouting)),
  77 };
  78
  79 const struct fw3_option fw3_zone_opts[] = {
  80         FW3_OPT("enabled",             bool,     zone,     enabled),
  81
  82         FW3_OPT("name",                string,   zone,     name),
  83         FW3_OPT("family",              family,   zone,     family),
  84
  85         FW3_LIST("network",            device,   zone,     networks),
  86         FW3_LIST("device",             device,   zone,     devices),
  87         FW3_LIST("subnet",             address,  zone,     subnets),
  88
  89         FW3_OPT("input",               target,   zone,     policy_input),
  90         FW3_OPT("forward",             target,   zone,     policy_forward),
  91         FW3_OPT("output",              target,   zone,     policy_output),
  92
  93         FW3_OPT("masq",                bool,     zone,     masq),
  94         FW3_LIST("masq_src",           address,  zone,     masq_src),
  95         FW3_LIST("masq_dest",          address,  zone,     masq_dest),
  96
  97         FW3_OPT("extra",               string,   zone,     extra_src),
  98         FW3_OPT("extra_src",           string,   zone,     extra_src),
  99         FW3_OPT("extra_dest",          string,   zone,     extra_dest),
 100
 101         FW3_OPT("conntrack",           bool,     zone,     conntrack),
 102         FW3_OPT("mtu_fix",             bool,     zone,     mtu_fix),
 103         FW3_OPT("custom_chains",       bool,     zone,     custom_chains),
 104
 105         FW3_OPT("log",                 bool,     zone,     log),
 106         FW3_OPT("log_limit",           limit,    zone,     log_limit),
 107
 108         { }
 109 };
 110
 111
 112 static bool
 113 print_chains(enum fw3_table table, enum fw3_family family,
 114              const char *fmt, const char *name, uint32_t targets,
 115              const struct chain *chains, int n)
 116 {
 117         bool rv = false;
 118         char cn[256] = { 0 };
 119         const struct chain *c;
 120
 121         for (c = chains; n > 0; c++, n--)
 122         {
 123                 if (!fw3_is_family(c, family))
 124                         continue;
 125
 126                 if (c->table != table)
 127                         continue;
 128
 129                 if ((c->target != FW3_TARGET_UNSPEC) && !hasbit(targets, c->target))
 130                         continue;
 131
 132                 snprintf(cn, sizeof(cn), c->name, name);
 133                 fw3_pr(fmt, cn);
 134
 135                 rv = true;
 136         }
 137
 138         return rv;
 139 }
 140
 141 static void
 142 check_policy(struct uci_element *e, enum fw3_target *pol, enum fw3_target def,
 143              const char *name)
 144 {
 145         if (*pol == FW3_TARGET_UNSPEC)
 146         {
 147                 warn_elem(e, "has no %s policy specified, using default", name);
 148                 *pol = def;
 149         }
 150         else if (*pol > FW3_TARGET_DROP)
 151         {
 152                 warn_elem(e, "has invalid %s policy, using default", name);
 153                 *pol = def;
 154         }
 155 }
 156
 157 static void
 158 resolve_networks(struct uci_element *e, struct fw3_zone *zone)
 159 {
 160         struct fw3_device *net, *tmp;
 161
 162         list_for_each_entry(net, &zone->networks, list)
 163         {
 164                 tmp = fw3_ubus_device(net->name);
 165
 166                 if (!tmp)
 167                 {
 168                         warn_elem(e, "cannot resolve device of network '%s'", net->name);
 169                         continue;
 170                 }
 171
 172                 list_add_tail(&tmp->list, &zone->devices);
 173         }
 174 }
 175
 176 struct fw3_zone *
 177 fw3_alloc_zone(void)
 178 {
 179         struct fw3_zone *zone;
 180
 181         zone = malloc(sizeof(*zone));
 182
 183         if (!zone)
 184                 return NULL;
 185
 186         memset(zone, 0, sizeof(*zone));
 187
 188         INIT_LIST_HEAD(&zone->networks);
 189         INIT_LIST_HEAD(&zone->devices);
 190         INIT_LIST_HEAD(&zone->subnets);
 191         INIT_LIST_HEAD(&zone->masq_src);
 192         INIT_LIST_HEAD(&zone->masq_dest);
 193
 194         zone->enabled = true;
 195         zone->custom_chains = true;
 196         zone->log_limit.rate = 10;
 197
 198         return zone;
 199 }
 200
 201 void
 202 fw3_load_zones(struct fw3_state *state, struct uci_package *p)
 203 {
 204         struct uci_section *s;
 205         struct uci_element *e;
 206         struct fw3_zone *zone;
 207         struct fw3_defaults *defs = &state->defaults;
 208
 209         INIT_LIST_HEAD(&state->zones);
 210
 211         uci_foreach_element(&p->sections, e)
 212         {
 213                 s = uci_to_section(e);
 214
 215                 if (strcmp(s->type, "zone"))
 216                         continue;
 217
 218                 zone = fw3_alloc_zone();
 219
 220                 if (!zone)
 221                         continue;
 222
 223                 fw3_parse_options(zone, fw3_zone_opts, s);
 224
 225                 if (!zone->enabled)
 226                 {
 227                         fw3_free_zone(zone);
 228                         continue;
 229                 }
 230
 231                 if (!zone->extra_dest)
 232                         zone->extra_dest = zone->extra_src;
 233
 234                 if (!defs->custom_chains && zone->custom_chains)
 235                         zone->custom_chains = false;
 236
 237                 if (!zone->name || !*zone->name)
 238                 {
 239                         warn_elem(e, "has no name - ignoring");
 240                         fw3_free_zone(zone);
 241                         continue;
 242                 }
 243
 244                 if (list_empty(&zone->networks) && list_empty(&zone->devices) &&
 245                     list_empty(&zone->subnets) && !zone->extra_src)
 246                 {
 247                         warn_elem(e, "has no device, network, subnet or extra options");
 248                 }
 249
 250                 check_policy(e, &zone->policy_input, defs->policy_input, "input");
 251                 check_policy(e, &zone->policy_output, defs->policy_output, "output");
 252                 check_policy(e, &zone->policy_forward, defs->policy_forward, "forward");
 253
 254                 resolve_networks(e, zone);
 255
 256                 if (zone->masq)
 257                 {
 258                         setbit(zone->dst_flags, FW3_TARGET_SNAT);
 259                         zone->conntrack = true;
 260                 }
 261
 262                 if (zone->custom_chains)
 263                 {
 264                         setbit(zone->dst_flags, FW3_TARGET_SNAT);
 265                         setbit(zone->dst_flags, FW3_TARGET_DNAT);
 266                 }
 267
 268                 setbit(zone->src_flags, zone->policy_input);
 269                 setbit(zone->dst_flags, zone->policy_output);
 270                 setbit(zone->dst_flags, 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, struct fw3_state *state)
 280 {
 281         bool s, d, r;
 282         enum fw3_target f;
 283         uint32_t custom_mask = ~0;
 284
 285         if (!fw3_is_family(zone, family))
 286                 return;
 287
 288         setbit(zone->dst_flags, family);
 289
 290         /* user chains already loaded, don't create again */
 291         for (f = FW3_TARGET_CUSTOM_CNS_V4; f <= FW3_TARGET_CUSTOM_CNS_V6; f++)
 292                 if (hasbit(zone->running_dst_flags, f))
 293                         delbit(custom_mask, f);
 294
 295         if (zone->custom_chains)
 296                 setbit(zone->dst_flags, (family == FW3_FAMILY_V4) ?
 297                        FW3_TARGET_CUSTOM_CNS_V4 : FW3_TARGET_CUSTOM_CNS_V6);
 298
 299         if (!zone->conntrack && !state->defaults.drop_invalid)
 300                 setbit(zone->dst_flags, FW3_TARGET_NOTRACK);
 301
 302         s = print_chains(table, family, ":%s - [0:0]\n", zone->name,
 303                          zone->src_flags,
 304                          src_chains, ARRAY_SIZE(src_chains));
 305
 306         d = print_chains(table, family, ":%s - [0:0]\n", zone->name,
 307                          zone->dst_flags & custom_mask,
 308                          dst_chains, ARRAY_SIZE(dst_chains));
 309
 310         r = print_chains(table, family, "-A %s\n", zone->name,
 311                          zone->dst_flags,
 312                          def_rules, ARRAY_SIZE(def_rules));
 313
 314         if (s || d || r)
 315         {
 316                 info("   * Zone '%s'", zone->name);
 317                 fw3_set_running(zone, &state->running_zones);
 318         }
 319 }
 320
 321 static void
 322 print_interface_rule(enum fw3_table table, enum fw3_family family,
 323                      struct fw3_zone *zone, struct fw3_device *dev,
 324                      struct fw3_address *sub, bool disable_notrack)
 325 {
 326         enum fw3_target t;
 327
 328 #define jump_target(t) \
 329         ((t == FW3_TARGET_REJECT) ? "reject" : fw3_flag_names[t])
 330
 331         if (table == FW3_TABLE_FILTER)
 332         {
 333                 for (t = FW3_TARGET_ACCEPT; t <= FW3_TARGET_DROP; t++)
 334                 {
 335                         if (hasbit(zone->src_flags, t))
 336                         {
 337                                 fw3_pr("-A zone_%s_src_%s", zone->name, fw3_flag_names[t]);
 338                                 fw3_format_in_out(dev, NULL);
 339                                 fw3_format_src_dest(sub, NULL);
 340                                 fw3_format_extra(zone->extra_src);
 341                                 fw3_pr(" -j %s\n", jump_target(t));
 342                         }
 343
 344                         if (hasbit(zone->dst_flags, t))
 345                         {
 346                                 fw3_pr("-A zone_%s_dest_%s", zone->name, fw3_flag_names[t]);
 347                                 fw3_format_in_out(NULL, dev);
 348                                 fw3_format_src_dest(NULL, sub);
 349                                 fw3_format_extra(zone->extra_dest);
 350                                 fw3_pr(" -j %s\n", jump_target(t));
 351                         }
 352                 }
 353
 354                 fw3_pr("-A delegate_input");
 355                 fw3_format_in_out(dev, NULL);
 356                 fw3_format_src_dest(sub, NULL);
 357                 fw3_format_extra(zone->extra_src);
 358                 fw3_pr(" -j zone_%s_input\n", zone->name);
 359
 360                 fw3_pr("-A delegate_forward");
 361                 fw3_format_in_out(dev, NULL);
 362                 fw3_format_src_dest(sub, NULL);
 363                 fw3_format_extra(zone->extra_src);
 364                 fw3_pr(" -j zone_%s_forward\n", zone->name);
 365
 366                 fw3_pr("-A delegate_output");
 367                 fw3_format_in_out(NULL, dev);
 368                 fw3_format_src_dest(NULL, sub);
 369                 fw3_format_extra(zone->extra_dest);
 370                 fw3_pr(" -j zone_%s_output\n", zone->name);
 371         }
 372         else if (table == FW3_TABLE_NAT)
 373         {
 374                 if (hasbit(zone->dst_flags, FW3_TARGET_DNAT))
 375                 {
 376                         fw3_pr("-A delegate_prerouting");
 377                         fw3_format_in_out(dev, NULL);
 378                         fw3_format_src_dest(sub, NULL);
 379                         fw3_format_extra(zone->extra_src);
 380                         fw3_pr(" -j zone_%s_prerouting\n", zone->name);
 381                 }
 382
 383                 if (hasbit(zone->dst_flags, FW3_TARGET_SNAT))
 384                 {
 385                         fw3_pr("-A delegate_postrouting");
 386                         fw3_format_in_out(NULL, dev);
 387                         fw3_format_src_dest(NULL, sub);
 388                         fw3_format_extra(zone->extra_dest);
 389                         fw3_pr(" -j zone_%s_postrouting\n", zone->name);
 390                 }
 391         }
 392         else if (table == FW3_TABLE_MANGLE)
 393         {
 394                 if (zone->mtu_fix)
 395                 {
 396                         if (zone->log)
 397                         {
 398                                 fw3_pr("-A mssfix");
 399                                 fw3_format_in_out(NULL, dev);
 400                                 fw3_format_src_dest(NULL, sub);
 401                                 fw3_pr(" -p tcp --tcp-flags SYN,RST SYN");
 402                                 fw3_format_limit(&zone->log_limit);
 403                                 fw3_format_comment(zone->name, " (mtu_fix logging)");
 404                                 fw3_pr(" -j LOG --log-prefix \"MSSFIX(%s): \"\n", zone->name);
 405                         }
 406
 407                         fw3_pr("-A mssfix");
 408                         fw3_format_in_out(NULL, dev);
 409                         fw3_format_src_dest(NULL, sub);
 410                         fw3_pr(" -p tcp --tcp-flags SYN,RST SYN");
 411                         fw3_format_comment(zone->name, " (mtu_fix)");
 412                         fw3_pr(" -j TCPMSS --clamp-mss-to-pmtu\n");
 413                 }
 414         }
 415         else if (table == FW3_TABLE_RAW)
 416         {
 417                 if (!zone->conntrack && !disable_notrack)
 418                 {
 419                         fw3_pr("-A notrack");
 420                         fw3_format_in_out(dev, NULL);
 421                         fw3_format_src_dest(sub, NULL);
 422                         fw3_format_extra(zone->extra_src);
 423                         fw3_format_comment(zone->name, " (notrack)");
 424                         fw3_pr(" -j CT --notrack\n", zone->name);
 425                 }
 426         }
 427 }
 428
 429 static void
 430 print_interface_rules(enum fw3_table table, enum fw3_family family,
 431                       struct fw3_zone *zone, bool disable_notrack)
 432 {
 433         struct fw3_device *dev;
 434         struct fw3_address *sub;
 435
 436         fw3_foreach(dev, &zone->devices)
 437         fw3_foreach(sub, &zone->subnets)
 438         {
 439                 if (!fw3_is_family(sub, family))
 440                         continue;
 441
 442                 if (!dev && !sub)
 443                         continue;
 444
 445                 print_interface_rule(table, family, zone, dev, sub, disable_notrack);
 446         }
 447 }
 448
 449 static void
 450 print_zone_rule(enum fw3_table table, enum fw3_family family,
 451                 struct fw3_zone *zone, bool disable_notrack)
 452 {
 453         struct fw3_address *msrc;
 454         struct fw3_address *mdest;
 455
 456         enum fw3_target t;
 457
 458         if (!fw3_is_family(zone, family))
 459                 return;
 460
 461         switch (table)
 462         {
 463         case FW3_TABLE_FILTER:
 464                 fw3_pr("-A zone_%s_input -j zone_%s_src_%s\n",
 465                            zone->name, zone->name, fw3_flag_names[zone->policy_input]);
 466
 467                 fw3_pr("-A zone_%s_forward -j zone_%s_dest_%s\n",
 468                            zone->name, zone->name, fw3_flag_names[zone->policy_forward]);
 469
 470                 fw3_pr("-A zone_%s_output -j zone_%s_dest_%s\n",
 471                            zone->name, zone->name, fw3_flag_names[zone->policy_output]);
 472
 473                 if (zone->log)
 474                 {
 475                         for (t = FW3_TARGET_REJECT; t <= FW3_TARGET_DROP; t++)
 476                         {
 477                                 if (hasbit(zone->src_flags, t))
 478                                 {
 479                                         fw3_pr("-A zone_%s_src_%s", zone->name, fw3_flag_names[t]);
 480                                         fw3_format_limit(&zone->log_limit);
 481                                         fw3_pr(" -j LOG --log-prefix \"%s(src %s)\"\n",
 482                                                    fw3_flag_names[t], zone->name);
 483                                 }
 484
 485                                 if (hasbit(zone->dst_flags, t))
 486                                 {
 487                                         fw3_pr("-A zone_%s_dest_%s", zone->name, fw3_flag_names[t]);
 488                                         fw3_format_limit(&zone->log_limit);
 489                                         fw3_pr(" -j LOG --log-prefix \"%s(dest %s)\"\n",
 490                                                    fw3_flag_names[t], zone->name);
 491                                 }
 492                         }
 493                 }
 494                 break;
 495
 496         case FW3_TABLE_NAT:
 497                 if (zone->masq && family == FW3_FAMILY_V4)
 498                 {
 499                         fw3_foreach(msrc, &zone->masq_src)
 500                         fw3_foreach(mdest, &zone->masq_dest)
 501                         {
 502                                 fw3_pr("-A zone_%s_postrouting ", zone->name);
 503                                 fw3_format_src_dest(msrc, mdest);
 504                                 fw3_pr("-j MASQUERADE\n");
 505                         }
 506                 }
 507                 break;
 508
 509         case FW3_TABLE_RAW:
 510         case FW3_TABLE_MANGLE:
 511                 break;
 512         }
 513
 514         print_interface_rules(table, family, zone, disable_notrack);
 515 }
 516
 517 void
 518 fw3_print_zone_chains(enum fw3_table table, enum fw3_family family,
 519                       struct fw3_state *state)
 520 {
 521         struct fw3_zone *zone;
 522
 523         list_for_each_entry(zone, &state->zones, list)
 524                 print_zone_chain(table, family, zone, state);
 525 }
 526
 527 void
 528 fw3_print_zone_rules(enum fw3_table table, enum fw3_family family,
 529                      struct fw3_state *state)
 530 {
 531         struct fw3_zone *zone;
 532
 533         list_for_each_entry(zone, &state->zones, list)
 534                 print_zone_rule(table, family, zone, state->defaults.drop_invalid);
 535 }
 536
 537 void
 538 fw3_flush_zones(enum fw3_table table, enum fw3_family family,
 539                             bool pass2, bool reload, struct fw3_state *state)
 540 {
 541         struct fw3_zone *z, *tmp;
 542         uint32_t custom_mask = ~0;
 543         uint32_t family_mask = (1 << FW3_FAMILY_V4) | (1 << FW3_FAMILY_V6);
 544
 545         /* don't touch user chains on selective stop */
 546         if (reload)
 547         {
 548                 delbit(custom_mask, FW3_TARGET_CUSTOM_CNS_V4);
 549                 delbit(custom_mask, FW3_TARGET_CUSTOM_CNS_V6);
 550         }
 551
 552         list_for_each_entry_safe(z, tmp, &state->running_zones, running_list)
 553         {
 554                 if (!hasbit(z->dst_flags, family))
 555                         continue;
 556
 557                 print_chains(table, family, pass2 ? "-X %s\n" : "-F %s\n",
 558                              z->name, z->running_src_flags,
 559                              src_chains, ARRAY_SIZE(src_chains));
 560
 561                 print_chains(table, family, pass2 ? "-X %s\n" : "-F %s\n",
 562                              z->name, z->running_dst_flags & custom_mask,
 563                              dst_chains, ARRAY_SIZE(dst_chains));
 564
 565                 if (pass2)
 566                 {
 567                         delbit(z->dst_flags, family);
 568
 569                         if (!(z->dst_flags & family_mask))
 570                                 fw3_set_running(z, NULL);
 571                 }
 572         }
 573 }
 574
 575 struct fw3_zone *
 576 fw3_lookup_zone(struct fw3_state *state, const char *name, bool running)
 577 {
 578         struct fw3_zone *z;
 579
 580         if (list_empty(&state->zones))
 581                 return NULL;
 582
 583         list_for_each_entry(z, &state->zones, list)
 584         {
 585                 if (strcmp(z->name, name))
 586                         continue;
 587
 588                 if (!running || z->running_list.next)
 589                         return z;
 590
 591                 break;
 592         }
 593
 594         return NULL;
 595 }