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 #define _GNU_SOURCE
  20 #include "utils.h"
  21 #include "options.h"
  22
  23 #include "zones.h"
  24 #include "ipsets.h"
  25
  26
  27 static int lock_fd = -1;
  28 static pid_t pipe_pid = -1;
  29 static FILE *pipe_fd = NULL;
  30
  31 bool fw3_pr_debug = false;
  32
  33
  34 static void
  35 warn_elem_section_name(struct uci_section *s, bool find_name)
  36 {
  37         int i = 0;
  38         struct uci_option *o;
  39         struct uci_element *tmp;
  40
  41         if (s->anonymous)
  42         {
  43                 uci_foreach_element(&s->package->sections, tmp)
  44                 {
  45                         if (strcmp(uci_to_section(tmp)->type, s->type))
  46                                 continue;
  47
  48                         if (&s->e == tmp)
  49                                 break;
  50
  51                         i++;
  52                 }
  53
  54                 fprintf(stderr, "@%s[%d]", s->type, i);
  55
  56                 if (find_name)
  57                 {
  58                         uci_foreach_element(&s->options, tmp)
  59                         {
  60                                 o = uci_to_option(tmp);
  61
  62                                 if (!strcmp(tmp->name, "name") && (o->type == UCI_TYPE_STRING))
  63                                 {
  64                                         fprintf(stderr, " (%s)", o->v.string);
  65                                         break;
  66                                 }
  67                         }
  68                 }
  69         }
  70         else
  71         {
  72                 fprintf(stderr, "'%s'", s->e.name);
  73         }
  74
  75         if (find_name)
  76                 fprintf(stderr, " ");
  77 }
  78
  79 void
  80 warn_elem(struct uci_element *e, const char *format, ...)
  81 {
  82         if (e->type == UCI_TYPE_SECTION)
  83         {
  84                 fprintf(stderr, "Warning: Section ");
  85                 warn_elem_section_name(uci_to_section(e), true);
  86         }
  87         else if (e->type == UCI_TYPE_OPTION)
  88         {
  89                 fprintf(stderr, "Warning: Option ");
  90                 warn_elem_section_name(uci_to_option(e)->section, false);
  91                 fprintf(stderr, ".%s ", e->name);
  92         }
  93
  94     va_list argptr;
  95     va_start(argptr, format);
  96     vfprintf(stderr, format, argptr);
  97     va_end(argptr);
  98
  99         fprintf(stderr, "\n");
 100 }
 101
 102 void
 103 warn(const char* format, ...)
 104 {
 105         fprintf(stderr, "Warning: ");
 106     va_list argptr;
 107     va_start(argptr, format);
 108     vfprintf(stderr, format, argptr);
 109     va_end(argptr);
 110         fprintf(stderr, "\n");
 111 }
 112
 113 void
 114 error(const char* format, ...)
 115 {
 116         fprintf(stderr, "Error: ");
 117     va_list argptr;
 118     va_start(argptr, format);
 119     vfprintf(stderr, format, argptr);
 120     va_end(argptr);
 121         fprintf(stderr, "\n");
 122
 123         exit(1);
 124 }
 125
 126 void
 127 info(const char* format, ...)
 128 {
 129         va_list argptr;
 130     va_start(argptr, format);
 131     vfprintf(stderr, format, argptr);
 132     va_end(argptr);
 133         fprintf(stderr, "\n");
 134 }
 135
 136 void *
 137 fw3_alloc(size_t size)
 138 {
 139         void *mem;
 140
 141         mem = calloc(1, size);
 142
 143         if (!mem)
 144                 error("Out of memory while allocating %d bytes", size);
 145
 146         return mem;
 147 }
 148
 149 char *
 150 fw3_strdup(const char *s)
 151 {
 152         char *ns;
 153
 154         ns = strdup(s);
 155
 156         if (!ns)
 157                 error("Out of memory while duplicating string '%s'", s);
 158
 159         return ns;
 160 }
 161
 162 const char *
 163 fw3_find_command(const char *cmd)
 164 {
 165         struct stat s;
 166         int plen = 0, clen = strlen(cmd) + 1;
 167         char *search, *p;
 168         static char path[PATH_MAX];
 169
 170         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 171                 return cmd;
 172
 173         search = getenv("PATH");
 174
 175         if (!search)
 176                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 177
 178         p = search;
 179
 180         do
 181         {
 182                 if (*p != ':' && *p != '\0')
 183                         continue;
 184
 185                 plen = p - search;
 186
 187                 if ((plen + clen) >= sizeof(path))
 188                         continue;
 189
 190                 strncpy(path, search, plen);
 191                 sprintf(path + plen, "/%s", cmd);
 192
 193                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 194                         return path;
 195
 196                 search = p + 1;
 197         }
 198         while (*p++);
 199
 200         return NULL;
 201 }
 202
 203 bool
 204 fw3_stdout_pipe(void)
 205 {
 206         pipe_fd = stdout;
 207         return true;
 208 }
 209
 210 bool
 211 __fw3_command_pipe(bool silent, const char *command, ...)
 212 {
 213         pid_t pid;
 214         va_list argp;
 215         int pfds[2];
 216         int argn;
 217         char *arg, **args, **tmp;
 218
 219         command = fw3_find_command(command);
 220
 221         if (!command)
 222                 return false;
 223
 224         if (pipe(pfds))
 225                 return false;
 226
 227         argn = 2;
 228         args = calloc(argn, sizeof(arg));
 229
 230         if (!args)
 231                 return false;
 232
 233         args[0] = (char *)command;
 234         args[1] = NULL;
 235
 236         va_start(argp, command);
 237
 238         while ((arg = va_arg(argp, char *)) != NULL)
 239         {
 240                 tmp = realloc(args, ++argn * sizeof(arg));
 241
 242                 if (!tmp)
 243                         break;
 244
 245                 args = tmp;
 246                 args[argn-2] = arg;
 247                 args[argn-1] = NULL;
 248         }
 249
 250         va_end(argp);
 251
 252         switch ((pid = fork()))
 253         {
 254         case -1:
 255                 return false;
 256
 257         case 0:
 258                 dup2(pfds[0], 0);
 259
 260                 close(pfds[0]);
 261                 close(pfds[1]);
 262
 263                 close(1);
 264
 265                 if (silent)
 266                         close(2);
 267
 268                 execv(command, args);
 269
 270         default:
 271                 signal(SIGPIPE, SIG_IGN);
 272                 pipe_pid = pid;
 273                 close(pfds[0]);
 274                 fcntl(pfds[1], F_SETFD, fcntl(pfds[1], F_GETFD) | FD_CLOEXEC);
 275         }
 276
 277         pipe_fd = fdopen(pfds[1], "w");
 278         return true;
 279 }
 280
 281 void
 282 fw3_pr(const char *fmt, ...)
 283 {
 284         va_list args;
 285
 286         if (fw3_pr_debug && pipe_fd != stdout)
 287         {
 288                 va_start(args, fmt);
 289                 vfprintf(stderr, fmt, args);
 290                 va_end(args);
 291         }
 292
 293         va_start(args, fmt);
 294         vfprintf(pipe_fd, fmt, args);
 295         va_end(args);
 296 }
 297
 298 void
 299 fw3_command_close(void)
 300 {
 301         if (pipe_fd && pipe_fd != stdout)
 302                 fclose(pipe_fd);
 303
 304         if (pipe_pid > -1)
 305                 waitpid(pipe_pid, NULL, 0);
 306
 307         signal(SIGPIPE, SIG_DFL);
 308
 309         pipe_fd = NULL;
 310         pipe_pid = -1;
 311 }
 312
 313 bool
 314 fw3_has_table(bool ipv6, const char *table)
 315 {
 316         FILE *f;
 317
 318         char line[12];
 319         bool seen = false;
 320
 321         const char *path = ipv6
 322                 ? "/proc/net/ip6_tables_names" : "/proc/net/ip_tables_names";
 323
 324         if (!(f = fopen(path, "r")))
 325                 return false;
 326
 327         while (fgets(line, sizeof(line), f))
 328         {
 329                 if (!strncmp(line, table, strlen(table)))
 330                 {
 331                         seen = true;
 332                         break;
 333                 }
 334         }
 335
 336         fclose(f);
 337
 338         return seen;
 339 }
 340
 341
 342 bool
 343 fw3_lock(void)
 344 {
 345         lock_fd = open(FW3_LOCKFILE, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 346
 347         if (lock_fd < 0)
 348         {
 349                 warn("Cannot create lock file %s: %s", FW3_LOCKFILE, strerror(errno));
 350                 return false;
 351         }
 352
 353         if (flock(lock_fd, LOCK_EX))
 354         {
 355                 warn("Cannot acquire exclusive lock: %s", strerror(errno));
 356                 return false;
 357         }
 358
 359         return true;
 360 }
 361
 362 void
 363 fw3_unlock(void)
 364 {
 365         if (lock_fd < 0)
 366                 return;
 367
 368         if (flock(lock_fd, LOCK_UN))
 369                 warn("Cannot release exclusive lock: %s", strerror(errno));
 370
 371         close(lock_fd);
 372         unlink(FW3_LOCKFILE);
 373
 374         lock_fd = -1;
 375 }
 376
 377
 378 static void
 379 write_defaults_uci(struct uci_context *ctx, struct fw3_defaults *d,
 380                    struct uci_package *dest)
 381 {
 382         char buf[sizeof("0xffffffff\0")];
 383         struct uci_ptr ptr = { .p = dest };
 384
 385         uci_add_section(ctx, dest, "defaults", &ptr.s);
 386
 387         ptr.o      = NULL;
 388         ptr.option = "input";
 389         ptr.value  = fw3_flag_names[d->policy_input];
 390         uci_set(ctx, &ptr);
 391
 392         ptr.o      = NULL;
 393         ptr.option = "output";
 394         ptr.value  = fw3_flag_names[d->policy_output];
 395         uci_set(ctx, &ptr);
 396
 397         ptr.o      = NULL;
 398         ptr.option = "forward";
 399         ptr.value  = fw3_flag_names[d->policy_forward];
 400         uci_set(ctx, &ptr);
 401
 402         sprintf(buf, "0x%x", d->flags[0]);
 403         ptr.o      = NULL;
 404         ptr.option = "__flags_v4";
 405         ptr.value  = buf;
 406         uci_set(ctx, &ptr);
 407
 408         sprintf(buf, "0x%x", d->flags[1]);
 409         ptr.o      = NULL;
 410         ptr.option = "__flags_v6";
 411         ptr.value  = buf;
 412         uci_set(ctx, &ptr);
 413 }
 414
 415 static void
 416 write_zone_uci(struct uci_context *ctx, struct fw3_zone *z,
 417                struct uci_package *dest)
 418 {
 419         struct fw3_device *dev;
 420         struct fw3_address *sub;
 421         enum fw3_family fam = FW3_FAMILY_ANY;
 422
 423         char *p, buf[34];
 424
 425         struct uci_ptr ptr = { .p = dest };
 426
 427         if (!z->enabled)
 428                 return;
 429
 430         if (fw3_no_table(z->flags[0]) && !fw3_no_table(z->flags[1]))
 431                 fam = FW3_FAMILY_V6;
 432         else if (!fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 433                 fam = FW3_FAMILY_V4;
 434         else if (fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 435                 return;
 436
 437         uci_add_section(ctx, dest, "zone", &ptr.s);
 438
 439         ptr.o      = NULL;
 440         ptr.option = "name";
 441         ptr.value  = z->name;
 442         uci_set(ctx, &ptr);
 443
 444         ptr.o      = NULL;
 445         ptr.option = "input";
 446         ptr.value  = fw3_flag_names[z->policy_input];
 447         uci_set(ctx, &ptr);
 448
 449         ptr.o      = NULL;
 450         ptr.option = "output";
 451         ptr.value  = fw3_flag_names[z->policy_output];
 452         uci_set(ctx, &ptr);
 453
 454         ptr.o      = NULL;
 455         ptr.option = "forward";
 456         ptr.value  = fw3_flag_names[z->policy_forward];
 457         uci_set(ctx, &ptr);
 458
 459         ptr.o      = NULL;
 460         ptr.option = "masq";
 461         ptr.value  = z->masq ? "1" : "0";
 462         uci_set(ctx, &ptr);
 463
 464         ptr.o      = NULL;
 465         ptr.option = "conntrack";
 466         ptr.value  = z->conntrack ? "1" : "0";
 467         uci_set(ctx, &ptr);
 468
 469         ptr.o      = NULL;
 470         ptr.option = "mtu_fix";
 471         ptr.value  = z->mtu_fix ? "1" : "0";
 472         uci_set(ctx, &ptr);
 473
 474         ptr.o      = NULL;
 475         ptr.option = "custom_chains";
 476         ptr.value  = z->custom_chains ? "1" : "0";
 477         uci_set(ctx, &ptr);
 478
 479         if (fam != FW3_FAMILY_ANY)
 480         {
 481                 ptr.o      = NULL;
 482                 ptr.option = "family";
 483                 ptr.value  = fw3_flag_names[fam];
 484                 uci_set(ctx, &ptr);
 485         }
 486
 487         ptr.o      = NULL;
 488         ptr.option = "device";
 489
 490         fw3_foreach(dev, &z->devices)
 491         {
 492                 if (!dev)
 493                         continue;
 494
 495                 p = buf;
 496
 497                 if (dev->invert)
 498                         p += sprintf(p, "!");
 499
 500                 if (*dev->network)
 501                         p += sprintf(p, "%s@%s", dev->name, dev->network);
 502                 else
 503                         p += sprintf(p, "%s", dev->name);
 504
 505                 ptr.value = buf;
 506                 uci_add_list(ctx, &ptr);
 507         }
 508
 509         ptr.o      = NULL;
 510         ptr.option = "subnet";
 511
 512         fw3_foreach(sub, &z->subnets)
 513         {
 514                 if (!sub)
 515                         continue;
 516
 517                 ptr.value = fw3_address_to_string(sub, true);
 518                 uci_add_list(ctx, &ptr);
 519         }
 520
 521         sprintf(buf, "0x%x", z->flags[0]);
 522         ptr.o      = NULL;
 523         ptr.option = "__flags_v4";
 524         ptr.value  = buf;
 525         uci_set(ctx, &ptr);
 526
 527         sprintf(buf, "0x%x", z->flags[1]);
 528         ptr.o      = NULL;
 529         ptr.option = "__flags_v6";
 530         ptr.value  = buf;
 531         uci_set(ctx, &ptr);
 532 }
 533
 534 static void
 535 write_ipset_uci(struct uci_context *ctx, struct fw3_ipset *s,
 536                 struct uci_package *dest)
 537 {
 538         struct fw3_ipset_datatype *type;
 539
 540         char buf[sizeof("65535-65535\0")];
 541
 542         struct uci_ptr ptr = { .p = dest };
 543
 544         if (!s->enabled || s->external)
 545                 return;
 546
 547         uci_add_section(ctx, dest, "ipset", &ptr.s);
 548
 549         ptr.o      = NULL;
 550         ptr.option = "name";
 551         ptr.value  = s->name;
 552         uci_set(ctx, &ptr);
 553
 554         ptr.o      = NULL;
 555         ptr.option = "storage";
 556         ptr.value  = fw3_ipset_method_names[s->method];
 557         uci_set(ctx, &ptr);
 558
 559         list_for_each_entry(type, &s->datatypes, list)
 560         {
 561                 sprintf(buf, "%s_%s", type->dir, fw3_ipset_type_names[type->type]);
 562                 ptr.o      = NULL;
 563                 ptr.option = "match";
 564                 ptr.value  = buf;
 565                 uci_add_list(ctx, &ptr);
 566         }
 567
 568         if (s->iprange.set)
 569         {
 570                 ptr.o      = NULL;
 571                 ptr.option = "iprange";
 572                 ptr.value  = fw3_address_to_string(&s->iprange, false);
 573                 uci_set(ctx, &ptr);
 574         }
 575
 576         if (s->portrange.set)
 577         {
 578                 sprintf(buf, "%u-%u", s->portrange.port_min, s->portrange.port_max);
 579                 ptr.o      = NULL;
 580                 ptr.option = "portrange";
 581                 ptr.value  = buf;
 582                 uci_set(ctx, &ptr);
 583         }
 584 }
 585
 586 void
 587 fw3_write_statefile(void *state)
 588 {
 589         FILE *sf;
 590         struct fw3_state *s = state;
 591         struct fw3_zone *z;
 592         struct fw3_ipset *i;
 593
 594         struct uci_package *p;
 595
 596         if (fw3_no_family(s->defaults.flags[0]) &&
 597             fw3_no_family(s->defaults.flags[1]))
 598         {
 599                 unlink(FW3_STATEFILE);
 600         }
 601         else
 602         {
 603                 sf = fopen(FW3_STATEFILE, "w+");
 604
 605                 if (!sf)
 606                 {
 607                         warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 608                         return;
 609                 }
 610
 611                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 612                         uci_unload(s->uci, p);
 613
 614                 uci_import(s->uci, sf, "fw3_state", NULL, true);
 615
 616                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 617                 {
 618                         write_defaults_uci(s->uci, &s->defaults, p);
 619
 620                         list_for_each_entry(z, &s->zones, list)
 621                                 write_zone_uci(s->uci, z, p);
 622
 623                         list_for_each_entry(i, &s->ipsets, list)
 624                                 write_ipset_uci(s->uci, i, p);
 625
 626                         uci_export(s->uci, sf, p, true);
 627                         uci_unload(s->uci, p);
 628                 }
 629
 630                 fsync(fileno(sf));
 631                 fclose(sf);
 632         }
 633 }
 634
 635
 636 void
 637 fw3_free_object(void *obj, const void *opts)
 638 {
 639         const struct fw3_option *ol;
 640         struct list_head *list, *cur, *tmp;
 641
 642         for (ol = opts; ol->name; ol++)
 643         {
 644                 if (!ol->elem_size)
 645                         continue;
 646
 647                 list = (struct list_head *)((char *)obj + ol->offset);
 648                 list_for_each_safe(cur, tmp, list)
 649                 {
 650                         list_del(cur);
 651                         free(cur);
 652                 }
 653         }
 654
 655         free(obj);
 656 }
 657
 658 void
 659 fw3_free_list(struct list_head *head)
 660 {
 661         struct list_head *entry, *tmp;
 662
 663         if (!head)
 664                 return;
 665
 666         list_for_each_safe(entry, tmp, head)
 667         {
 668                 list_del(entry);
 669                 free(entry);
 670         }
 671
 672         free(head);
 673 }
 674
 675 bool
 676 fw3_hotplug(bool add, void *zone, void *device)
 677 {
 678         struct fw3_zone *z = zone;
 679         struct fw3_device *d = device;
 680
 681         if (!*d->network)
 682                 return false;
 683
 684         switch (fork())
 685         {
 686         case -1:
 687                 warn("Unable to fork(): %s\n", strerror(errno));
 688                 return false;
 689
 690         case 0:
 691                 break;
 692
 693         default:
 694                 return true;
 695         }
 696
 697         close(0);
 698         close(1);
 699         close(2);
 700         if (chdir("/")) {};
 701
 702         clearenv();
 703         setenv("ACTION",    add ? "add" : "remove", 1);
 704         setenv("ZONE",      z->name,                1);
 705         setenv("INTERFACE", d->network,             1);
 706         setenv("DEVICE",    d->name,                1);
 707
 708         execl(FW3_HOTPLUG, FW3_HOTPLUG, "firewall", NULL);
 709
 710         /* unreached */
 711         return false;
 712 }