rules.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013-2018 Jo-Philipp Wich <jo@mein.io>
   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 "rules.h"
  20
  21
  22 const struct fw3_option fw3_rule_opts[] = {
  23         FW3_OPT("enabled",             bool,      rule,     enabled),
  24
  25         FW3_OPT("name",                string,    rule,     name),
  26         FW3_OPT("family",              family,    rule,     family),
  27
  28         FW3_OPT("src",                 device,    rule,     src),
  29         FW3_OPT("dest",                device,    rule,     dest),
  30
  31         FW3_OPT("device",              string,    rule,     device),
  32         FW3_OPT("direction",           direction, rule,     direction_out),
  33
  34         FW3_OPT("ipset",               setmatch,  rule,     ipset),
  35         FW3_OPT("helper",              cthelper,  rule,     helper),
  36         FW3_OPT("set_helper",          cthelper,  rule,     set_helper),
  37
  38         FW3_LIST("proto",              protocol,  rule,     proto),
  39
  40         FW3_LIST("src_ip",             network,   rule,     ip_src),
  41         FW3_LIST("src_mac",            mac,       rule,     mac_src),
  42         FW3_LIST("src_port",           port,      rule,     port_src),
  43
  44         FW3_LIST("dest_ip",            network,   rule,     ip_dest),
  45         FW3_LIST("dest_port",          port,      rule,     port_dest),
  46
  47         FW3_LIST("icmp_type",          icmptype,  rule,     icmp_type),
  48         FW3_OPT("extra",               string,    rule,     extra),
  49
  50         FW3_OPT("limit",               limit,     rule,     limit),
  51         FW3_OPT("limit_burst",         int,       rule,     limit.burst),
  52
  53         FW3_OPT("utc_time",            bool,      rule,     time.utc),
  54         FW3_OPT("start_date",          date,      rule,     time.datestart),
  55         FW3_OPT("stop_date",           date,      rule,     time.datestop),
  56         FW3_OPT("start_time",          time,      rule,     time.timestart),
  57         FW3_OPT("stop_time",           time,      rule,     time.timestop),
  58         FW3_OPT("weekdays",            weekdays,  rule,     time.weekdays),
  59         FW3_OPT("monthdays",           monthdays, rule,     time.monthdays),
  60
  61         FW3_OPT("mark",                mark,      rule,     mark),
  62         FW3_OPT("set_mark",            mark,      rule,     set_mark),
  63         FW3_OPT("set_xmark",           mark,      rule,     set_xmark),
  64
  65         FW3_OPT("dscp",                dscp,      rule,     dscp),
  66         FW3_OPT("set_dscp",            dscp,      rule,     set_dscp),
  67
  68         FW3_OPT("target",              target,    rule,     target),
  69
  70         { }
  71 };
  72
  73
  74 static bool
  75 need_src_action_chain(struct fw3_rule *r)
  76 {
  77         return (r->_src && r->_src->log && (r->target > FW3_FLAG_ACCEPT));
  78 }
  79
  80 static struct fw3_rule*
  81 alloc_rule(struct fw3_state *state)
  82 {
  83         struct fw3_rule *rule = calloc(1, sizeof(*rule));
  84
  85         if (rule) {
  86                 INIT_LIST_HEAD(&rule->proto);
  87
  88                 INIT_LIST_HEAD(&rule->ip_src);
  89                 INIT_LIST_HEAD(&rule->mac_src);
  90                 INIT_LIST_HEAD(&rule->port_src);
  91
  92                 INIT_LIST_HEAD(&rule->ip_dest);
  93                 INIT_LIST_HEAD(&rule->port_dest);
  94
  95                 INIT_LIST_HEAD(&rule->icmp_type);
  96
  97                 list_add_tail(&rule->list, &state->rules);
  98                 rule->enabled = true;
  99         }
 100
 101         return rule;
 102 }
 103
 104 static bool
 105 check_rule(struct fw3_state *state, struct fw3_rule *r, struct uci_element *e)
 106 {
 107         if (!r->enabled)
 108                 return false;
 109
 110         if (r->src.invert || r->dest.invert)
 111         {
 112                 warn_section("rule", r, e, "must not have inverted 'src' or 'dest' options");
 113                 return false;
 114         }
 115         else if (r->src.set && !r->src.any &&
 116                  !(r->_src = fw3_lookup_zone(state, r->src.name)))
 117         {
 118                 warn_section("rule", r, e, "refers to not existing zone '%s'", r->src.name);
 119                 return false;
 120         }
 121         else if (r->dest.set && !r->dest.any &&
 122                  !(r->_dest = fw3_lookup_zone(state, r->dest.name)))
 123         {
 124                 warn_section("rule", r, e, "refers to not existing zone '%s'", r->dest.name);
 125                 return false;
 126         }
 127         else if (r->ipset.set && state->disable_ipsets)
 128         {
 129                 warn_section("rule", r, e, "skipped due to disabled ipset support");
 130                 return false;
 131         }
 132         else if (r->ipset.set &&
 133                  !(r->ipset.ptr = fw3_lookup_ipset(state, r->ipset.name)))
 134         {
 135                 warn_section("rule", r, e, "refers to unknown ipset '%s'", r->ipset.name);
 136                 return false;
 137         }
 138         else if (r->helper.set &&
 139                  !(r->helper.ptr = fw3_lookup_cthelper(state, r->helper.name)))
 140         {
 141                 warn_section("rule", r, e, "refers to unknown CT helper '%s'", r->helper.name);
 142                 return false;
 143         }
 144         else if (r->set_helper.set &&
 145                  !(r->set_helper.ptr = fw3_lookup_cthelper(state, r->set_helper.name)))
 146         {
 147                 warn_section("rule", r, e, "refers to unknown CT helper '%s'", r->set_helper.name);
 148                 return false;
 149         }
 150
 151         if (!r->_src && (r->target == FW3_FLAG_NOTRACK || r->target == FW3_FLAG_HELPER))
 152         {
 153                 warn_section("rule", r, e, "is set to target %s but has no source assigned",
 154                              fw3_flag_names[r->target]);
 155                 return false;
 156         }
 157
 158         if (!r->set_mark.set && !r->set_xmark.set &&
 159             r->target == FW3_FLAG_MARK)
 160         {
 161                 warn_section("rule", r, e, "is set to target MARK but specifies neither "
 162                                            "'set_mark' nor 'set_xmark' option");
 163                 return false;
 164         }
 165
 166         if (!r->set_dscp.set && r->target == FW3_FLAG_DSCP)
 167         {
 168                 warn_section("rule", r, e, "is set to target DSCP but specifies no "
 169                                            "'set_dscp' option");
 170                 return false;
 171         }
 172
 173         if (r->set_mark.invert || r->set_xmark.invert || r->set_dscp.invert)
 174         {
 175                 warn_section("rule", r, e, "must not have inverted 'set_mark', "
 176                                            "'set_xmark' or 'set_dscp'");
 177                 return false;
 178         }
 179
 180         if (!r->set_helper.set && r->target == FW3_FLAG_HELPER)
 181         {
 182                 warn_section("rule", r, e, "is set to target HELPER but specifies "
 183                                            "no 'set_helper' option");
 184                 return false;
 185         }
 186
 187         if (r->set_helper.invert && r->target == FW3_FLAG_HELPER)
 188         {
 189                 warn_section("rule", r, e, "must not have inverted 'set_helper' option");
 190                 return false;
 191         }
 192
 193         if (!r->_src && !r->_dest && !r->src.any && !r->dest.any)
 194         {
 195                 warn_section("rule", r, e, "has neither a source nor a destination zone assigned "
 196                                 "- assuming an output rule");
 197         }
 198
 199         if (list_empty(&r->proto))
 200         {
 201                 warn_section("rule", r, e, "does not specify a protocol, assuming TCP+UDP");
 202                 fw3_parse_protocol(&r->proto, "tcpudp", true);
 203         }
 204
 205         if (r->target == FW3_FLAG_UNSPEC)
 206         {
 207                 warn_section("rule", r, e, "has no target specified, defaulting to REJECT");
 208                 r->target = FW3_FLAG_REJECT;
 209         }
 210         else if (r->target > FW3_FLAG_DSCP)
 211         {
 212                 warn_section("rule", r, e, "has invalid target specified, defaulting to REJECT");
 213                 r->target = FW3_FLAG_REJECT;
 214         }
 215
 216         /* NB: r family... */
 217         if (r->_dest)
 218         {
 219                 fw3_setbit(r->_dest->flags[0], r->target);
 220                 fw3_setbit(r->_dest->flags[1], r->target);
 221         }
 222         else if (need_src_action_chain(r))
 223         {
 224                 fw3_setbit(r->_src->flags[0], fw3_to_src_target(r->target));
 225                 fw3_setbit(r->_src->flags[1], fw3_to_src_target(r->target));
 226         }
 227
 228         return true;
 229 }
 230
 231 void
 232 fw3_load_rules(struct fw3_state *state, struct uci_package *p,
 233                 struct blob_attr *a)
 234 {
 235         struct uci_section *s;
 236         struct uci_element *e;
 237         struct fw3_rule *rule;
 238         struct blob_attr *entry;
 239         unsigned rem;
 240
 241         INIT_LIST_HEAD(&state->rules);
 242
 243         blob_for_each_attr(entry, a, rem) {
 244                 const char *type;
 245                 const char *name = "ubus rule";
 246
 247                 if (!fw3_attr_parse_name_type(entry, &name, &type))
 248                         continue;
 249
 250                 if (strcmp(type, "rule"))
 251                         continue;
 252
 253                 if (!(rule = alloc_rule(state)))
 254                         continue;
 255
 256                 if (!fw3_parse_blob_options(rule, fw3_rule_opts, entry, name))
 257                 {
 258                         warn_section("rule", rule, NULL, "skipped due to invalid options");
 259                         fw3_free_rule(rule);
 260                         continue;
 261                 }
 262
 263                 if (!check_rule(state, rule, NULL))
 264                         fw3_free_rule(rule);
 265         }
 266
 267         uci_foreach_element(&p->sections, e)
 268         {
 269                 s = uci_to_section(e);
 270
 271                 if (strcmp(s->type, "rule"))
 272                         continue;
 273
 274                 if (!(rule = alloc_rule(state)))
 275                         continue;
 276
 277                 if (!fw3_parse_options(rule, fw3_rule_opts, s))
 278                 {
 279                         warn_elem(e, "skipped due to invalid options");
 280                         fw3_free_rule(rule);
 281                         continue;
 282                 }
 283
 284                 if (!check_rule(state, rule, e))
 285                         fw3_free_rule(rule);
 286         }
 287 }
 288
 289
 290 static void
 291 append_chain(struct fw3_ipt_rule *r, struct fw3_rule *rule)
 292 {
 293         char chain[32];
 294
 295         snprintf(chain, sizeof(chain), "OUTPUT");
 296
 297         if (rule->target == FW3_FLAG_NOTRACK)
 298         {
 299                 snprintf(chain, sizeof(chain), "zone_%s_notrack", rule->src.name);
 300         }
 301         else if (rule->target == FW3_FLAG_HELPER)
 302         {
 303                 snprintf(chain, sizeof(chain), "zone_%s_helper", rule->src.name);
 304         }
 305         else if (rule->target == FW3_FLAG_MARK || rule->target == FW3_FLAG_DSCP)
 306         {
 307                 if ((rule->_dest && rule->_src) ||
 308                     (rule->dest.any && rule->src.any))
 309                         snprintf(chain, sizeof(chain), "FORWARD");
 310                 else if (rule->src.any && rule->_dest)
 311                         snprintf(chain, sizeof(chain), "POSTROUTING");
 312                 else if (rule->dest.any && rule->_src)
 313                         snprintf(chain, sizeof(chain), "PREROUTING");
 314                 else if (!rule->dest.set && rule->src.set)
 315                         snprintf(chain, sizeof(chain), "INPUT");
 316                 else /* if (!rule->src.set) */
 317                         snprintf(chain, sizeof(chain), "OUTPUT");
 318         }
 319         else
 320         {
 321                 if (rule->src.set)
 322                 {
 323                         if (!rule->src.any)
 324                         {
 325                                 if (rule->dest.set)
 326                                         snprintf(chain, sizeof(chain), "zone_%s_forward",
 327                                                  rule->src.name);
 328                                 else
 329                                         snprintf(chain, sizeof(chain), "zone_%s_input",
 330                                                  rule->src.name);
 331                         }
 332                         else
 333                         {
 334                                 if (rule->dest.set)
 335                                         snprintf(chain, sizeof(chain), "FORWARD");
 336                                 else
 337                                         snprintf(chain, sizeof(chain), "INPUT");
 338                         }
 339                 }
 340
 341                 if (rule->dest.set && !rule->src.set)
 342                 {
 343                         if (rule->dest.any)
 344                                 snprintf(chain, sizeof(chain), "OUTPUT");
 345                         else
 346                                 snprintf(chain, sizeof(chain), "zone_%s_output",
 347                                          rule->dest.name);
 348                 }
 349         }
 350
 351         fw3_ipt_rule_append(r, chain);
 352 }
 353
 354 static void set_target(struct fw3_ipt_rule *r, struct fw3_rule *rule)
 355 {
 356         const char *name;
 357         struct fw3_mark *mark;
 358         char buf[sizeof("0xFFFFFFFF/0xFFFFFFFF")];
 359
 360         switch(rule->target)
 361         {
 362         case FW3_FLAG_MARK:
 363                 name = rule->set_mark.set ? "--set-mark" : "--set-xmark";
 364                 mark = rule->set_mark.set ? &rule->set_mark : &rule->set_xmark;
 365                 snprintf(buf, sizeof(buf), "0x%x/0x%x", mark->mark, mark->mask);
 366
 367                 fw3_ipt_rule_target(r, "MARK");
 368                 fw3_ipt_rule_addarg(r, false, name, buf);
 369                 return;
 370
 371         case FW3_FLAG_DSCP:
 372                 snprintf(buf, sizeof(buf), "0x%x", rule->set_dscp.dscp);
 373
 374                 fw3_ipt_rule_target(r, "DSCP");
 375                 fw3_ipt_rule_addarg(r, false, "--set-dscp", buf);
 376                 return;
 377
 378         case FW3_FLAG_NOTRACK:
 379                 fw3_ipt_rule_target(r, "CT");
 380                 fw3_ipt_rule_addarg(r, false, "--notrack", NULL);
 381                 return;
 382
 383         case FW3_FLAG_HELPER:
 384                 fw3_ipt_rule_target(r, "CT");
 385                 fw3_ipt_rule_addarg(r, false, "--helper", rule->set_helper.ptr->name);
 386                 return;
 387
 388         case FW3_FLAG_ACCEPT:
 389         case FW3_FLAG_DROP:
 390                 name = fw3_flag_names[rule->target];
 391                 break;
 392
 393         default:
 394                 name = fw3_flag_names[FW3_FLAG_REJECT];
 395                 break;
 396         }
 397
 398         if (rule->dest.set && !rule->dest.any)
 399                 fw3_ipt_rule_target(r, "zone_%s_dest_%s", rule->dest.name, name);
 400         else if (need_src_action_chain(rule))
 401                 fw3_ipt_rule_target(r, "zone_%s_src_%s", rule->src.name, name);
 402         else if (strcmp(name, "REJECT"))
 403                 fw3_ipt_rule_target(r, name);
 404         else
 405                 fw3_ipt_rule_target(r, "reject");
 406 }
 407
 408 static void
 409 set_comment(struct fw3_ipt_rule *r, const char *name, int num)
 410 {
 411         if (name)
 412                 fw3_ipt_rule_comment(r, name);
 413         else
 414                 fw3_ipt_rule_comment(r, "@rule[%u]", num);
 415 }
 416
 417 static void
 418 print_rule(struct fw3_ipt_handle *handle, struct fw3_state *state,
 419            struct fw3_rule *rule, int num, struct fw3_protocol *proto,
 420            struct fw3_address *sip, struct fw3_address *dip,
 421            struct fw3_port *sport, struct fw3_port *dport,
 422            struct fw3_mac *mac, struct fw3_icmptype *icmptype)
 423 {
 424         struct fw3_ipt_rule *r;
 425         struct fw3_device *idev, *odev;
 426         struct list_head empty, *idevices, *odevices;
 427         INIT_LIST_HEAD(&empty);
 428         idevices = odevices = &empty;
 429
 430         if (!fw3_is_family(sip, handle->family) ||
 431             !fw3_is_family(dip, handle->family))
 432         {
 433                 if ((sip && !sip->resolved) || (dip && !dip->resolved))
 434                         info("     ! Skipping due to different family of ip address");
 435
 436                 return;
 437         }
 438
 439         if (!fw3_is_family(sip, handle->family) ||
 440             !fw3_is_family(dip, handle->family))
 441         {
 442                 if ((sip && !sip->resolved) || (dip && !dip->resolved))
 443                         info("     ! Skipping due to different family of ip address");
 444
 445                 return;
 446         }
 447
 448         if (!fw3_is_family(sip, handle->family) ||
 449             !fw3_is_family(dip, handle->family))
 450         {
 451                 if ((sip && !sip->resolved) || (dip && !dip->resolved))
 452                         info("     ! Skipping due to different family of ip address");
 453
 454                 return;
 455         }
 456
 457         if (proto->protocol == 58 && handle->family == FW3_FAMILY_V4)
 458         {
 459                 info("     ! Skipping protocol %s due to different family",
 460                      fw3_protoname(proto));
 461                 return;
 462         }
 463
 464         if (rule->helper.ptr &&
 465             !fw3_cthelper_check_proto(rule->helper.ptr, proto))
 466         {
 467                 info("     ! Skipping protocol %s since helper '%s' does not support it",
 468                      fw3_protoname(proto), rule->helper.ptr->name);
 469                 return;
 470         }
 471
 472         if (rule->set_helper.ptr &&
 473             !fw3_cthelper_check_proto(rule->set_helper.ptr, proto))
 474         {
 475                 info("     ! Skipping protocol %s since helper '%s' does not support it",
 476                      fw3_protoname(proto), rule->helper.ptr->name);
 477                 return;
 478         }
 479
 480         if (rule->target == FW3_FLAG_DSCP || rule->target == FW3_FLAG_MARK)
 481         {
 482                 if (rule->_src)
 483                         idevices = &rule->_src->devices;
 484                 if (rule->_dest)
 485                         odevices = &rule->_dest->devices;
 486         }
 487
 488         fw3_foreach(idev, idevices)
 489         fw3_foreach(odev, odevices)
 490         {
 491                 r = fw3_ipt_rule_create(handle, proto, idev, odev, sip, dip);
 492                 fw3_ipt_rule_sport_dport(r, sport, dport);
 493                 fw3_ipt_rule_device(r, rule->device, rule->direction_out);
 494                 fw3_ipt_rule_icmptype(r, icmptype);
 495                 fw3_ipt_rule_mac(r, mac);
 496                 fw3_ipt_rule_ipset(r, &rule->ipset);
 497                 fw3_ipt_rule_helper(r, &rule->helper);
 498                 fw3_ipt_rule_limit(r, &rule->limit);
 499                 fw3_ipt_rule_time(r, &rule->time);
 500                 fw3_ipt_rule_mark(r, &rule->mark);
 501                 fw3_ipt_rule_dscp(r, &rule->dscp);
 502                 set_target(r, rule);
 503                 fw3_ipt_rule_extra(r, rule->extra);
 504                 set_comment(r, rule->name, num);
 505                 append_chain(r, rule);
 506         }
 507 }
 508
 509 static void
 510 expand_rule(struct fw3_ipt_handle *handle, struct fw3_state *state,
 511             struct fw3_rule *rule, int num)
 512 {
 513         struct fw3_protocol *proto;
 514         struct fw3_address *sip;
 515         struct fw3_address *dip;
 516         struct fw3_port *sport;
 517         struct fw3_port *dport;
 518         struct fw3_mac *mac;
 519         struct fw3_icmptype *icmptype;
 520
 521         struct list_head *sports = NULL;
 522         struct list_head *dports = NULL;
 523         struct list_head *icmptypes = NULL;
 524
 525         struct list_head empty;
 526         INIT_LIST_HEAD(&empty);
 527
 528         if (!fw3_is_family(rule, handle->family))
 529                 return;
 530
 531         if ((rule->target == FW3_FLAG_NOTRACK && handle->table != FW3_TABLE_RAW) ||
 532             (rule->target == FW3_FLAG_HELPER && handle->table != FW3_TABLE_RAW)  ||
 533             (rule->target == FW3_FLAG_MARK && handle->table != FW3_TABLE_MANGLE) ||
 534             (rule->target == FW3_FLAG_DSCP && handle->table != FW3_TABLE_MANGLE) ||
 535                 (rule->target < FW3_FLAG_NOTRACK && handle->table != FW3_TABLE_FILTER))
 536                 return;
 537
 538         if (rule->name)
 539                 info("   * Rule '%s'", rule->name);
 540         else
 541                 info("   * Rule #%u", num);
 542
 543         if (!fw3_is_family(rule->_src, handle->family) ||
 544             !fw3_is_family(rule->_dest, handle->family))
 545         {
 546                 info("     ! Skipping due to different family of zone");
 547                 return;
 548         }
 549
 550         if (rule->ipset.ptr)
 551         {
 552                 if (!fw3_is_family(rule->ipset.ptr, handle->family))
 553                 {
 554                         info("     ! Skipping due to different family in ipset");
 555                         return;
 556                 }
 557
 558                 if (!fw3_check_ipset(rule->ipset.ptr))
 559                 {
 560                         info("     ! Skipping due to missing ipset '%s'",
 561                              rule->ipset.ptr->external
 562                                         ? rule->ipset.ptr->external : rule->ipset.ptr->name);
 563                         return;
 564                 }
 565
 566                 set(rule->ipset.ptr->flags, handle->family, handle->family);
 567         }
 568
 569         if (rule->helper.ptr && !fw3_is_family(rule->helper.ptr, handle->family))
 570         {
 571                 info("     ! Skipping due to unsupported family of CT helper");
 572                 return;
 573         }
 574
 575         if (rule->set_helper.ptr && !fw3_is_family(rule->set_helper.ptr, handle->family))
 576         {
 577                 info("     ! Skipping due to unsupported family of CT helper");
 578                 return;
 579         }
 580
 581         list_for_each_entry(proto, &rule->proto, list)
 582         {
 583                 /* icmp / ipv6-icmp */
 584                 if (proto->protocol == 1 || proto->protocol == 58)
 585                 {
 586                         sports = &empty;
 587                         dports = &empty;
 588                         icmptypes = &rule->icmp_type;
 589                 }
 590                 else
 591                 {
 592                         sports = &rule->port_src;
 593                         dports = &rule->port_dest;
 594                         icmptypes = &empty;
 595                 }
 596
 597                 fw3_foreach(sip, &rule->ip_src)
 598                 fw3_foreach(dip, &rule->ip_dest)
 599                 fw3_foreach(sport, sports)
 600                 fw3_foreach(dport, dports)
 601                 fw3_foreach(mac, &rule->mac_src)
 602                 fw3_foreach(icmptype, icmptypes)
 603                         print_rule(handle, state, rule, num, proto, sip, dip,
 604                                    sport, dport, mac, icmptype);
 605         }
 606 }
 607
 608 void
 609 fw3_print_rules(struct fw3_ipt_handle *handle, struct fw3_state *state)
 610 {
 611         int num = 0;
 612         struct fw3_rule *rule;
 613
 614         list_for_each_entry(rule, &state->rules, list)
 615                 expand_rule(handle, state, rule, num++);
 616 }