utils.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 "utils.h"
  20 #include "options.h"
  21
  22 #include "zones.h"
  23 #include "ipsets.h"
  24
  25
  26 static int lock_fd = -1;
  27 static pid_t pipe_pid = -1;
  28 static FILE *pipe_fd = NULL;
  29
  30 bool fw3_pr_debug = false;
  31
  32
  33 static void
  34 warn_elem_section_name(struct uci_section *s, bool find_name)
  35 {
  36         int i = 0;
  37         struct uci_option *o;
  38         struct uci_element *tmp;
  39
  40         if (s->anonymous)
  41         {
  42                 uci_foreach_element(&s->package->sections, tmp)
  43                 {
  44                         if (strcmp(uci_to_section(tmp)->type, s->type))
  45                                 continue;
  46
  47                         if (&s->e == tmp)
  48                                 break;
  49
  50                         i++;
  51                 }
  52
  53                 fprintf(stderr, "@%s[%d]", s->type, i);
  54
  55                 if (find_name)
  56                 {
  57                         uci_foreach_element(&s->options, tmp)
  58                         {
  59                                 o = uci_to_option(tmp);
  60
  61                                 if (!strcmp(tmp->name, "name") && (o->type == UCI_TYPE_STRING))
  62                                 {
  63                                         fprintf(stderr, " (%s)", o->v.string);
  64                                         break;
  65                                 }
  66                         }
  67                 }
  68         }
  69         else
  70         {
  71                 fprintf(stderr, "'%s'", s->e.name);
  72         }
  73
  74         if (find_name)
  75                 fprintf(stderr, " ");
  76 }
  77
  78 void
  79 warn_elem(struct uci_element *e, const char *format, ...)
  80 {
  81         if (e->type == UCI_TYPE_SECTION)
  82         {
  83                 fprintf(stderr, "Warning: Section ");
  84                 warn_elem_section_name(uci_to_section(e), true);
  85         }
  86         else if (e->type == UCI_TYPE_OPTION)
  87         {
  88                 fprintf(stderr, "Warning: Option ");
  89                 warn_elem_section_name(uci_to_option(e)->section, false);
  90                 fprintf(stderr, ".%s ", e->name);
  91         }
  92
  93     va_list argptr;
  94     va_start(argptr, format);
  95     vfprintf(stderr, format, argptr);
  96     va_end(argptr);
  97
  98         fprintf(stderr, "\n");
  99 }
 100
 101 void
 102 warn(const char* format, ...)
 103 {
 104         fprintf(stderr, "Warning: ");
 105     va_list argptr;
 106     va_start(argptr, format);
 107     vfprintf(stderr, format, argptr);
 108     va_end(argptr);
 109         fprintf(stderr, "\n");
 110 }
 111
 112 void
 113 error(const char* format, ...)
 114 {
 115         fprintf(stderr, "Error: ");
 116     va_list argptr;
 117     va_start(argptr, format);
 118     vfprintf(stderr, format, argptr);
 119     va_end(argptr);
 120         fprintf(stderr, "\n");
 121
 122         exit(1);
 123 }
 124
 125 void
 126 info(const char* format, ...)
 127 {
 128         va_list argptr;
 129     va_start(argptr, format);
 130     vfprintf(stderr, format, argptr);
 131     va_end(argptr);
 132         fprintf(stderr, "\n");
 133 }
 134
 135 const char *
 136 fw3_find_command(const char *cmd)
 137 {
 138         struct stat s;
 139         int plen = 0, clen = strlen(cmd) + 1;
 140         char *search, *p;
 141         static char path[PATH_MAX];
 142
 143         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 144                 return cmd;
 145
 146         search = getenv("PATH");
 147
 148         if (!search)
 149                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 150
 151         p = search;
 152
 153         do
 154         {
 155                 if (*p != ':' && *p != '\0')
 156                         continue;
 157
 158                 plen = p - search;
 159
 160                 if ((plen + clen) >= sizeof(path))
 161                         continue;
 162
 163                 strncpy(path, search, plen);
 164                 sprintf(path + plen, "/%s", cmd);
 165
 166                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 167                         return path;
 168
 169                 search = p + 1;
 170         }
 171         while (*p++);
 172
 173         return NULL;
 174 }
 175
 176 bool
 177 fw3_stdout_pipe(void)
 178 {
 179         pipe_fd = stdout;
 180         return true;
 181 }
 182
 183 bool
 184 __fw3_command_pipe(bool silent, const char *command, ...)
 185 {
 186         pid_t pid;
 187         va_list argp;
 188         int pfds[2];
 189         int argn;
 190         char *arg, **args, **tmp;
 191
 192         command = fw3_find_command(command);
 193
 194         if (!command)
 195                 return false;
 196
 197         if (pipe(pfds))
 198                 return false;
 199
 200         argn = 2;
 201         args = malloc(argn * sizeof(arg));
 202
 203         if (!args)
 204                 return false;
 205
 206         args[0] = (char *)command;
 207         args[1] = NULL;
 208
 209         va_start(argp, command);
 210
 211         while ((arg = va_arg(argp, char *)) != NULL)
 212         {
 213                 tmp = realloc(args, ++argn * sizeof(arg));
 214
 215                 if (!tmp)
 216                         break;
 217
 218                 args = tmp;
 219                 args[argn-2] = arg;
 220                 args[argn-1] = NULL;
 221         }
 222
 223         va_end(argp);
 224
 225         switch ((pid = fork()))
 226         {
 227         case -1:
 228                 return false;
 229
 230         case 0:
 231                 dup2(pfds[0], 0);
 232
 233                 close(pfds[0]);
 234                 close(pfds[1]);
 235
 236                 close(1);
 237
 238                 if (silent)
 239                         close(2);
 240
 241                 execv(command, args);
 242
 243         default:
 244                 signal(SIGPIPE, SIG_IGN);
 245                 pipe_pid = pid;
 246                 close(pfds[0]);
 247                 fcntl(pfds[1], F_SETFD, fcntl(pfds[1], F_GETFD) | FD_CLOEXEC);
 248         }
 249
 250         pipe_fd = fdopen(pfds[1], "w");
 251         return true;
 252 }
 253
 254 void
 255 fw3_pr(const char *fmt, ...)
 256 {
 257         va_list args;
 258
 259         if (fw3_pr_debug && pipe_fd != stdout)
 260         {
 261                 va_start(args, fmt);
 262                 vfprintf(stderr, fmt, args);
 263                 va_end(args);
 264         }
 265
 266         va_start(args, fmt);
 267         vfprintf(pipe_fd, fmt, args);
 268         va_end(args);
 269 }
 270
 271 void
 272 fw3_command_close(void)
 273 {
 274         if (pipe_fd && pipe_fd != stdout)
 275                 fclose(pipe_fd);
 276
 277         if (pipe_pid > -1)
 278                 waitpid(pipe_pid, NULL, 0);
 279
 280         signal(SIGPIPE, SIG_DFL);
 281
 282         pipe_fd = NULL;
 283         pipe_pid = -1;
 284 }
 285
 286 bool
 287 fw3_has_table(bool ipv6, const char *table)
 288 {
 289         FILE *f;
 290
 291         char line[12];
 292         bool seen = false;
 293
 294         const char *path = ipv6
 295                 ? "/proc/net/ip6_tables_names" : "/proc/net/ip_tables_names";
 296
 297         if (!(f = fopen(path, "r")))
 298                 return false;
 299
 300         while (fgets(line, sizeof(line), f))
 301         {
 302                 if (!strncmp(line, table, strlen(table)))
 303                 {
 304                         seen = true;
 305                         break;
 306                 }
 307         }
 308
 309         fclose(f);
 310
 311         return seen;
 312 }
 313
 314
 315 bool
 316 fw3_lock(void)
 317 {
 318         lock_fd = open(FW3_LOCKFILE, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 319
 320         if (lock_fd < 0)
 321         {
 322                 warn("Cannot create lock file %s: %s", FW3_LOCKFILE, strerror(errno));
 323                 return false;
 324         }
 325
 326         if (flock(lock_fd, LOCK_EX))
 327         {
 328                 warn("Cannot acquire exclusive lock: %s", strerror(errno));
 329                 return false;
 330         }
 331
 332         return true;
 333 }
 334
 335 void
 336 fw3_unlock(void)
 337 {
 338         if (lock_fd < 0)
 339                 return;
 340
 341         if (flock(lock_fd, LOCK_UN))
 342                 warn("Cannot release exclusive lock: %s", strerror(errno));
 343
 344         close(lock_fd);
 345         unlink(FW3_LOCKFILE);
 346
 347         lock_fd = -1;
 348 }
 349
 350
 351 static void
 352 write_defaults_uci(struct uci_context *ctx, struct fw3_defaults *d,
 353                    struct uci_package *dest)
 354 {
 355         char buf[sizeof("0xffffffff\0")];
 356         struct uci_ptr ptr = { .p = dest };
 357
 358         uci_add_section(ctx, dest, "defaults", &ptr.s);
 359
 360         ptr.o      = NULL;
 361         ptr.option = "input";
 362         ptr.value  = fw3_flag_names[d->policy_input];
 363         uci_set(ctx, &ptr);
 364
 365         ptr.o      = NULL;
 366         ptr.option = "output";
 367         ptr.value  = fw3_flag_names[d->policy_output];
 368         uci_set(ctx, &ptr);
 369
 370         ptr.o      = NULL;
 371         ptr.option = "forward";
 372         ptr.value  = fw3_flag_names[d->policy_forward];
 373         uci_set(ctx, &ptr);
 374
 375         sprintf(buf, "0x%x", d->flags[0]);
 376         ptr.o      = NULL;
 377         ptr.option = "__flags_v4";
 378         ptr.value  = buf;
 379         uci_set(ctx, &ptr);
 380
 381         sprintf(buf, "0x%x", d->flags[1]);
 382         ptr.o      = NULL;
 383         ptr.option = "__flags_v6";
 384         ptr.value  = buf;
 385         uci_set(ctx, &ptr);
 386 }
 387
 388 static void
 389 write_zone_uci(struct uci_context *ctx, struct fw3_zone *z,
 390                struct uci_package *dest)
 391 {
 392         struct fw3_device *dev;
 393         struct fw3_address *sub;
 394         enum fw3_family fam = FW3_FAMILY_ANY;
 395
 396         char *p, buf[34];
 397
 398         struct uci_ptr ptr = { .p = dest };
 399
 400         if (!z->enabled)
 401                 return;
 402
 403         if (fw3_no_table(z->flags[0]) && !fw3_no_table(z->flags[1]))
 404                 fam = FW3_FAMILY_V6;
 405         else if (!fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 406                 fam = FW3_FAMILY_V4;
 407         else if (fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 408                 return;
 409
 410         uci_add_section(ctx, dest, "zone", &ptr.s);
 411
 412         ptr.o      = NULL;
 413         ptr.option = "name";
 414         ptr.value  = z->name;
 415         uci_set(ctx, &ptr);
 416
 417         ptr.o      = NULL;
 418         ptr.option = "input";
 419         ptr.value  = fw3_flag_names[z->policy_input];
 420         uci_set(ctx, &ptr);
 421
 422         ptr.o      = NULL;
 423         ptr.option = "output";
 424         ptr.value  = fw3_flag_names[z->policy_output];
 425         uci_set(ctx, &ptr);
 426
 427         ptr.o      = NULL;
 428         ptr.option = "forward";
 429         ptr.value  = fw3_flag_names[z->policy_forward];
 430         uci_set(ctx, &ptr);
 431
 432         ptr.o      = NULL;
 433         ptr.option = "masq";
 434         ptr.value  = z->masq ? "1" : "0";
 435         uci_set(ctx, &ptr);
 436
 437         ptr.o      = NULL;
 438         ptr.option = "conntrack";
 439         ptr.value  = z->conntrack ? "1" : "0";
 440         uci_set(ctx, &ptr);
 441
 442         ptr.o      = NULL;
 443         ptr.option = "mtu_fix";
 444         ptr.value  = z->mtu_fix ? "1" : "0";
 445         uci_set(ctx, &ptr);
 446
 447         ptr.o      = NULL;
 448         ptr.option = "custom_chains";
 449         ptr.value  = z->custom_chains ? "1" : "0";
 450         uci_set(ctx, &ptr);
 451
 452         if (fam != FW3_FAMILY_ANY)
 453         {
 454                 ptr.o      = NULL;
 455                 ptr.option = "family";
 456                 ptr.value  = fw3_flag_names[fam];
 457                 uci_set(ctx, &ptr);
 458         }
 459
 460         ptr.o      = NULL;
 461         ptr.option = "device";
 462
 463         fw3_foreach(dev, &z->devices)
 464         {
 465                 if (!dev)
 466                         continue;
 467
 468                 p = buf;
 469
 470                 if (dev->invert)
 471                         p += sprintf(p, "!");
 472
 473                 if (*dev->network)
 474                         p += sprintf(p, "%s@%s", dev->name, dev->network);
 475                 else
 476                         p += sprintf(p, "%s", dev->name);
 477
 478                 ptr.value = buf;
 479                 uci_add_list(ctx, &ptr);
 480         }
 481
 482         ptr.o      = NULL;
 483         ptr.option = "subnet";
 484
 485         fw3_foreach(sub, &z->subnets)
 486         {
 487                 if (!sub)
 488                         continue;
 489
 490                 ptr.value = fw3_address_to_string(sub, true);
 491                 uci_add_list(ctx, &ptr);
 492         }
 493
 494         sprintf(buf, "0x%x", z->flags[0]);
 495         ptr.o      = NULL;
 496         ptr.option = "__flags_v4";
 497         ptr.value  = buf;
 498         uci_set(ctx, &ptr);
 499
 500         sprintf(buf, "0x%x", z->flags[1]);
 501         ptr.o      = NULL;
 502         ptr.option = "__flags_v6";
 503         ptr.value  = buf;
 504         uci_set(ctx, &ptr);
 505 }
 506
 507 static void
 508 write_ipset_uci(struct uci_context *ctx, struct fw3_ipset *s,
 509                 struct uci_package *dest)
 510 {
 511         struct fw3_ipset_datatype *type;
 512
 513         char buf[sizeof("65535-65535\0")];
 514
 515         struct uci_ptr ptr = { .p = dest };
 516
 517         if (!s->enabled || (s->external && *s->external))
 518                 return;
 519
 520         uci_add_section(ctx, dest, "ipset", &ptr.s);
 521
 522         ptr.o      = NULL;
 523         ptr.option = "name";
 524         ptr.value  = s->name;
 525         uci_set(ctx, &ptr);
 526
 527         ptr.o      = NULL;
 528         ptr.option = "storage";
 529         ptr.value  = fw3_ipset_method_names[s->method];
 530         uci_set(ctx, &ptr);
 531
 532         list_for_each_entry(type, &s->datatypes, list)
 533         {
 534                 sprintf(buf, "%s_%s", type->dest ? "dst" : "src",
 535                                       fw3_ipset_type_names[type->type]);
 536
 537                 ptr.o      = NULL;
 538                 ptr.option = "match";
 539                 ptr.value  = buf;
 540                 uci_add_list(ctx, &ptr);
 541         }
 542
 543         if (s->iprange.set)
 544         {
 545                 ptr.o      = NULL;
 546                 ptr.option = "iprange";
 547                 ptr.value  = fw3_address_to_string(&s->iprange, false);
 548                 uci_set(ctx, &ptr);
 549         }
 550
 551         if (s->portrange.set)
 552         {
 553                 sprintf(buf, "%u-%u", s->portrange.port_min, s->portrange.port_max);
 554                 ptr.o      = NULL;
 555                 ptr.option = "portrange";
 556                 ptr.value  = buf;
 557                 uci_set(ctx, &ptr);
 558         }
 559 }
 560
 561 void
 562 fw3_write_statefile(void *state)
 563 {
 564         FILE *sf;
 565         struct fw3_state *s = state;
 566         struct fw3_zone *z;
 567         struct fw3_ipset *i;
 568
 569         struct uci_package *p;
 570
 571         if (fw3_no_family(s->defaults.flags[0]) &&
 572             fw3_no_family(s->defaults.flags[1]))
 573         {
 574                 unlink(FW3_STATEFILE);
 575         }
 576         else
 577         {
 578                 sf = fopen(FW3_STATEFILE, "w+");
 579
 580                 if (!sf)
 581                 {
 582                         warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 583                         return;
 584                 }
 585
 586                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 587                         uci_unload(s->uci, p);
 588
 589                 uci_import(s->uci, sf, "fw3_state", NULL, true);
 590
 591                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 592                 {
 593                         write_defaults_uci(s->uci, &s->defaults, p);
 594
 595                         list_for_each_entry(z, &s->zones, list)
 596                                 write_zone_uci(s->uci, z, p);
 597
 598                         list_for_each_entry(i, &s->ipsets, list)
 599                                 write_ipset_uci(s->uci, i, p);
 600
 601                         uci_export(s->uci, sf, p, true);
 602                         uci_unload(s->uci, p);
 603                 }
 604
 605                 fclose(sf);
 606         }
 607 }
 608
 609
 610 void
 611 fw3_free_object(void *obj, const void *opts)
 612 {
 613         const struct fw3_option *ol;
 614         struct list_head *list, *cur, *tmp;
 615
 616         for (ol = opts; ol->name; ol++)
 617         {
 618                 if (!ol->elem_size)
 619                         continue;
 620
 621                 list = (struct list_head *)((char *)obj + ol->offset);
 622                 list_for_each_safe(cur, tmp, list)
 623                 {
 624                         list_del(cur);
 625                         free(cur);
 626                 }
 627         }
 628
 629         free(obj);
 630 }
 631
 632
 633 bool
 634 fw3_pr_rulespec(int table, int family, uint32_t *flags, uint32_t mask,
 635                 const struct fw3_rule_spec *r, const char *fmt, ...)
 636 {
 637         char buf[256];
 638         bool rv = false;
 639
 640         va_list ap;
 641         uint32_t f = flags ? flags[family == FW3_FAMILY_V6] : 0;
 642
 643         if (mask)
 644                 f &= mask;
 645
 646         for (; r->format; r++)
 647         {
 648                 if (!fw3_is_family(r, family))
 649                         continue;
 650
 651                 if (r->table != table)
 652                         continue;
 653
 654                 if ((r->flag != 0) && !hasbit(f, r->flag))
 655                         continue;
 656
 657                 va_start(ap, fmt);
 658                 vsnprintf(buf, sizeof(buf), r->format, ap);
 659                 va_end(ap);
 660
 661                 fw3_pr(fmt, buf);
 662
 663                 rv = true;
 664         }
 665
 666         return rv;
 667 }
 668
 669
 670 bool
 671 fw3_hotplug(bool add, void *zone, void *device)
 672 {
 673         struct fw3_zone *z = zone;
 674         struct fw3_device *d = device;
 675
 676         if (!*d->network)
 677                 return false;
 678
 679         switch (fork())
 680         {
 681         case -1:
 682                 warn("Unable to fork(): %s\n", strerror(errno));
 683                 return false;
 684
 685         case 0:
 686                 break;
 687
 688         default:
 689                 return true;
 690         }
 691
 692         close(0);
 693         close(1);
 694         close(2);
 695         chdir("/");
 696
 697         clearenv();
 698         setenv("ACTION",    add ? "add" : "remove", 1);
 699         setenv("ZONE",      z->name,                1);
 700         setenv("INTERFACE", d->network,             1);
 701         setenv("DEVICE",    d->name,                1);
 702
 703         execl(FW3_HOTPLUG, FW3_HOTPLUG, "firewall", NULL);
 704
 705         /* unreached */
 706         return false;
 707 }