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 void *
 136 fw3_alloc(size_t size)
 137 {
 138         void *mem;
 139
 140         mem = calloc(1, size);
 141
 142         if (!mem)
 143                 error("Out of memory while allocating %d bytes", size);
 144
 145         return mem;
 146 }
 147
 148 char *
 149 fw3_strdup(const char *s)
 150 {
 151         char *ns;
 152
 153         ns = strdup(s);
 154
 155         if (!ns)
 156                 error("Out of memory while duplicating string '%s'", s);
 157
 158         return ns;
 159 }
 160
 161 const char *
 162 fw3_find_command(const char *cmd)
 163 {
 164         struct stat s;
 165         int plen = 0, clen = strlen(cmd) + 1;
 166         char *search, *p;
 167         static char path[PATH_MAX];
 168
 169         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 170                 return cmd;
 171
 172         search = getenv("PATH");
 173
 174         if (!search)
 175                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 176
 177         p = search;
 178
 179         do
 180         {
 181                 if (*p != ':' && *p != '\0')
 182                         continue;
 183
 184                 plen = p - search;
 185
 186                 if ((plen + clen) >= sizeof(path))
 187                         continue;
 188
 189                 strncpy(path, search, plen);
 190                 sprintf(path + plen, "/%s", cmd);
 191
 192                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 193                         return path;
 194
 195                 search = p + 1;
 196         }
 197         while (*p++);
 198
 199         return NULL;
 200 }
 201
 202 bool
 203 fw3_stdout_pipe(void)
 204 {
 205         pipe_fd = stdout;
 206         return true;
 207 }
 208
 209 bool
 210 __fw3_command_pipe(bool silent, const char *command, ...)
 211 {
 212         pid_t pid;
 213         va_list argp;
 214         int pfds[2];
 215         int argn;
 216         char *arg, **args, **tmp;
 217
 218         command = fw3_find_command(command);
 219
 220         if (!command)
 221                 return false;
 222
 223         if (pipe(pfds))
 224                 return false;
 225
 226         argn = 2;
 227         args = malloc(argn * sizeof(arg));
 228
 229         if (!args)
 230                 return false;
 231
 232         args[0] = (char *)command;
 233         args[1] = NULL;
 234
 235         va_start(argp, command);
 236
 237         while ((arg = va_arg(argp, char *)) != NULL)
 238         {
 239                 tmp = realloc(args, ++argn * sizeof(arg));
 240
 241                 if (!tmp)
 242                         break;
 243
 244                 args = tmp;
 245                 args[argn-2] = arg;
 246                 args[argn-1] = NULL;
 247         }
 248
 249         va_end(argp);
 250
 251         switch ((pid = fork()))
 252         {
 253         case -1:
 254                 return false;
 255
 256         case 0:
 257                 dup2(pfds[0], 0);
 258
 259                 close(pfds[0]);
 260                 close(pfds[1]);
 261
 262                 close(1);
 263
 264                 if (silent)
 265                         close(2);
 266
 267                 execv(command, args);
 268
 269         default:
 270                 signal(SIGPIPE, SIG_IGN);
 271                 pipe_pid = pid;
 272                 close(pfds[0]);
 273                 fcntl(pfds[1], F_SETFD, fcntl(pfds[1], F_GETFD) | FD_CLOEXEC);
 274         }
 275
 276         pipe_fd = fdopen(pfds[1], "w");
 277         return true;
 278 }
 279
 280 void
 281 fw3_pr(const char *fmt, ...)
 282 {
 283         va_list args;
 284
 285         if (fw3_pr_debug && pipe_fd != stdout)
 286         {
 287                 va_start(args, fmt);
 288                 vfprintf(stderr, fmt, args);
 289                 va_end(args);
 290         }
 291
 292         va_start(args, fmt);
 293         vfprintf(pipe_fd, fmt, args);
 294         va_end(args);
 295 }
 296
 297 void
 298 fw3_command_close(void)
 299 {
 300         if (pipe_fd && pipe_fd != stdout)
 301                 fclose(pipe_fd);
 302
 303         if (pipe_pid > -1)
 304                 waitpid(pipe_pid, NULL, 0);
 305
 306         signal(SIGPIPE, SIG_DFL);
 307
 308         pipe_fd = NULL;
 309         pipe_pid = -1;
 310 }
 311
 312 bool
 313 fw3_has_table(bool ipv6, const char *table)
 314 {
 315         FILE *f;
 316
 317         char line[12];
 318         bool seen = false;
 319
 320         const char *path = ipv6
 321                 ? "/proc/net/ip6_tables_names" : "/proc/net/ip_tables_names";
 322
 323         if (!(f = fopen(path, "r")))
 324                 return false;
 325
 326         while (fgets(line, sizeof(line), f))
 327         {
 328                 if (!strncmp(line, table, strlen(table)))
 329                 {
 330                         seen = true;
 331                         break;
 332                 }
 333         }
 334
 335         fclose(f);
 336
 337         return seen;
 338 }
 339
 340
 341 bool
 342 fw3_lock(void)
 343 {
 344         lock_fd = open(FW3_LOCKFILE, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 345
 346         if (lock_fd < 0)
 347         {
 348                 warn("Cannot create lock file %s: %s", FW3_LOCKFILE, strerror(errno));
 349                 return false;
 350         }
 351
 352         if (flock(lock_fd, LOCK_EX))
 353         {
 354                 warn("Cannot acquire exclusive lock: %s", strerror(errno));
 355                 return false;
 356         }
 357
 358         return true;
 359 }
 360
 361 void
 362 fw3_unlock(void)
 363 {
 364         if (lock_fd < 0)
 365                 return;
 366
 367         if (flock(lock_fd, LOCK_UN))
 368                 warn("Cannot release exclusive lock: %s", strerror(errno));
 369
 370         close(lock_fd);
 371         unlink(FW3_LOCKFILE);
 372
 373         lock_fd = -1;
 374 }
 375
 376
 377 static void
 378 write_defaults_uci(struct uci_context *ctx, struct fw3_defaults *d,
 379                    struct uci_package *dest)
 380 {
 381         char buf[sizeof("0xffffffff\0")];
 382         struct uci_ptr ptr = { .p = dest };
 383
 384         uci_add_section(ctx, dest, "defaults", &ptr.s);
 385
 386         ptr.o      = NULL;
 387         ptr.option = "input";
 388         ptr.value  = fw3_flag_names[d->policy_input];
 389         uci_set(ctx, &ptr);
 390
 391         ptr.o      = NULL;
 392         ptr.option = "output";
 393         ptr.value  = fw3_flag_names[d->policy_output];
 394         uci_set(ctx, &ptr);
 395
 396         ptr.o      = NULL;
 397         ptr.option = "forward";
 398         ptr.value  = fw3_flag_names[d->policy_forward];
 399         uci_set(ctx, &ptr);
 400
 401         sprintf(buf, "0x%x", d->flags[0]);
 402         ptr.o      = NULL;
 403         ptr.option = "__flags_v4";
 404         ptr.value  = buf;
 405         uci_set(ctx, &ptr);
 406
 407         sprintf(buf, "0x%x", d->flags[1]);
 408         ptr.o      = NULL;
 409         ptr.option = "__flags_v6";
 410         ptr.value  = buf;
 411         uci_set(ctx, &ptr);
 412 }
 413
 414 static void
 415 write_zone_uci(struct uci_context *ctx, struct fw3_zone *z,
 416                struct uci_package *dest)
 417 {
 418         struct fw3_device *dev;
 419         struct fw3_address *sub;
 420         enum fw3_family fam = FW3_FAMILY_ANY;
 421
 422         char *p, buf[34];
 423
 424         struct uci_ptr ptr = { .p = dest };
 425
 426         if (!z->enabled)
 427                 return;
 428
 429         if (fw3_no_table(z->flags[0]) && !fw3_no_table(z->flags[1]))
 430                 fam = FW3_FAMILY_V6;
 431         else if (!fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 432                 fam = FW3_FAMILY_V4;
 433         else if (fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 434                 return;
 435
 436         uci_add_section(ctx, dest, "zone", &ptr.s);
 437
 438         ptr.o      = NULL;
 439         ptr.option = "name";
 440         ptr.value  = z->name;
 441         uci_set(ctx, &ptr);
 442
 443         ptr.o      = NULL;
 444         ptr.option = "input";
 445         ptr.value  = fw3_flag_names[z->policy_input];
 446         uci_set(ctx, &ptr);
 447
 448         ptr.o      = NULL;
 449         ptr.option = "output";
 450         ptr.value  = fw3_flag_names[z->policy_output];
 451         uci_set(ctx, &ptr);
 452
 453         ptr.o      = NULL;
 454         ptr.option = "forward";
 455         ptr.value  = fw3_flag_names[z->policy_forward];
 456         uci_set(ctx, &ptr);
 457
 458         ptr.o      = NULL;
 459         ptr.option = "masq";
 460         ptr.value  = z->masq ? "1" : "0";
 461         uci_set(ctx, &ptr);
 462
 463         ptr.o      = NULL;
 464         ptr.option = "conntrack";
 465         ptr.value  = z->conntrack ? "1" : "0";
 466         uci_set(ctx, &ptr);
 467
 468         ptr.o      = NULL;
 469         ptr.option = "mtu_fix";
 470         ptr.value  = z->mtu_fix ? "1" : "0";
 471         uci_set(ctx, &ptr);
 472
 473         ptr.o      = NULL;
 474         ptr.option = "custom_chains";
 475         ptr.value  = z->custom_chains ? "1" : "0";
 476         uci_set(ctx, &ptr);
 477
 478         if (fam != FW3_FAMILY_ANY)
 479         {
 480                 ptr.o      = NULL;
 481                 ptr.option = "family";
 482                 ptr.value  = fw3_flag_names[fam];
 483                 uci_set(ctx, &ptr);
 484         }
 485
 486         ptr.o      = NULL;
 487         ptr.option = "device";
 488
 489         fw3_foreach(dev, &z->devices)
 490         {
 491                 if (!dev)
 492                         continue;
 493
 494                 p = buf;
 495
 496                 if (dev->invert)
 497                         p += sprintf(p, "!");
 498
 499                 if (*dev->network)
 500                         p += sprintf(p, "%s@%s", dev->name, dev->network);
 501                 else
 502                         p += sprintf(p, "%s", dev->name);
 503
 504                 ptr.value = buf;
 505                 uci_add_list(ctx, &ptr);
 506         }
 507
 508         ptr.o      = NULL;
 509         ptr.option = "subnet";
 510
 511         fw3_foreach(sub, &z->subnets)
 512         {
 513                 if (!sub)
 514                         continue;
 515
 516                 ptr.value = fw3_address_to_string(sub, true);
 517                 uci_add_list(ctx, &ptr);
 518         }
 519
 520         sprintf(buf, "0x%x", z->flags[0]);
 521         ptr.o      = NULL;
 522         ptr.option = "__flags_v4";
 523         ptr.value  = buf;
 524         uci_set(ctx, &ptr);
 525
 526         sprintf(buf, "0x%x", z->flags[1]);
 527         ptr.o      = NULL;
 528         ptr.option = "__flags_v6";
 529         ptr.value  = buf;
 530         uci_set(ctx, &ptr);
 531 }
 532
 533 static void
 534 write_ipset_uci(struct uci_context *ctx, struct fw3_ipset *s,
 535                 struct uci_package *dest)
 536 {
 537         struct fw3_ipset_datatype *type;
 538
 539         char buf[sizeof("65535-65535\0")];
 540
 541         struct uci_ptr ptr = { .p = dest };
 542
 543         if (!s->enabled || s->external)
 544                 return;
 545
 546         uci_add_section(ctx, dest, "ipset", &ptr.s);
 547
 548         ptr.o      = NULL;
 549         ptr.option = "name";
 550         ptr.value  = s->name;
 551         uci_set(ctx, &ptr);
 552
 553         ptr.o      = NULL;
 554         ptr.option = "storage";
 555         ptr.value  = fw3_ipset_method_names[s->method];
 556         uci_set(ctx, &ptr);
 557
 558         list_for_each_entry(type, &s->datatypes, list)
 559         {
 560                 sprintf(buf, "%s_%s", type->dest ? "dst" : "src",
 561                                       fw3_ipset_type_names[type->type]);
 562
 563                 ptr.o      = NULL;
 564                 ptr.option = "match";
 565                 ptr.value  = buf;
 566                 uci_add_list(ctx, &ptr);
 567         }
 568
 569         if (s->iprange.set)
 570         {
 571                 ptr.o      = NULL;
 572                 ptr.option = "iprange";
 573                 ptr.value  = fw3_address_to_string(&s->iprange, false);
 574                 uci_set(ctx, &ptr);
 575         }
 576
 577         if (s->portrange.set)
 578         {
 579                 sprintf(buf, "%u-%u", s->portrange.port_min, s->portrange.port_max);
 580                 ptr.o      = NULL;
 581                 ptr.option = "portrange";
 582                 ptr.value  = buf;
 583                 uci_set(ctx, &ptr);
 584         }
 585 }
 586
 587 void
 588 fw3_write_statefile(void *state)
 589 {
 590         FILE *sf;
 591         struct fw3_state *s = state;
 592         struct fw3_zone *z;
 593         struct fw3_ipset *i;
 594
 595         struct uci_package *p;
 596
 597         if (fw3_no_family(s->defaults.flags[0]) &&
 598             fw3_no_family(s->defaults.flags[1]))
 599         {
 600                 unlink(FW3_STATEFILE);
 601         }
 602         else
 603         {
 604                 sf = fopen(FW3_STATEFILE, "w+");
 605
 606                 if (!sf)
 607                 {
 608                         warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 609                         return;
 610                 }
 611
 612                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 613                         uci_unload(s->uci, p);
 614
 615                 uci_import(s->uci, sf, "fw3_state", NULL, true);
 616
 617                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 618                 {
 619                         write_defaults_uci(s->uci, &s->defaults, p);
 620
 621                         list_for_each_entry(z, &s->zones, list)
 622                                 write_zone_uci(s->uci, z, p);
 623
 624                         list_for_each_entry(i, &s->ipsets, list)
 625                                 write_ipset_uci(s->uci, i, p);
 626
 627                         uci_export(s->uci, sf, p, true);
 628                         uci_unload(s->uci, p);
 629                 }
 630
 631                 fsync(fileno(sf));
 632                 fclose(sf);
 633         }
 634 }
 635
 636
 637 void
 638 fw3_free_object(void *obj, const void *opts)
 639 {
 640         const struct fw3_option *ol;
 641         struct list_head *list, *cur, *tmp;
 642
 643         for (ol = opts; ol->name; ol++)
 644         {
 645                 if (!ol->elem_size)
 646                         continue;
 647
 648                 list = (struct list_head *)((char *)obj + ol->offset);
 649                 list_for_each_safe(cur, tmp, list)
 650                 {
 651                         list_del(cur);
 652                         free(cur);
 653                 }
 654         }
 655
 656         free(obj);
 657 }
 658
 659
 660 bool
 661 fw3_hotplug(bool add, void *zone, void *device)
 662 {
 663         struct fw3_zone *z = zone;
 664         struct fw3_device *d = device;
 665
 666         if (!*d->network)
 667                 return false;
 668
 669         switch (fork())
 670         {
 671         case -1:
 672                 warn("Unable to fork(): %s\n", strerror(errno));
 673                 return false;
 674
 675         case 0:
 676                 break;
 677
 678         default:
 679                 return true;
 680         }
 681
 682         close(0);
 683         close(1);
 684         close(2);
 685         chdir("/");
 686
 687         clearenv();
 688         setenv("ACTION",    add ? "add" : "remove", 1);
 689         setenv("ZONE",      z->name,                1);
 690         setenv("INTERFACE", d->network,             1);
 691         setenv("DEVICE",    d->name,                1);
 692
 693         execl(FW3_HOTPLUG, FW3_HOTPLUG, "firewall", NULL);
 694
 695         /* unreached */
 696         return false;
 697 }