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 bool
 352 fw3_read_statefile(void *state)
 353 {
 354         FILE *sf;
 355
 356         int type;
 357         char line[128];
 358         const char *p, *name;
 359
 360         uint32_t flags[2];
 361
 362         struct fw3_state *s = state;
 363         struct fw3_zone *zone;
 364         struct fw3_ipset *ipset;
 365         struct fw3_device *net, *dev;
 366
 367         sf = fopen(FW3_STATEFILE, "r");
 368
 369         if (!sf)
 370                 return false;
 371
 372         while (fgets(line, sizeof(line), sf))
 373         {
 374                 p = strtok(line, " \t\n");
 375
 376                 if (!p)
 377                         continue;
 378
 379                 type = strtoul(p, NULL, 16);
 380                 name = strtok(NULL, " \t\n");
 381
 382                 if (!name)
 383                         continue;
 384
 385                 if (!(p = strtok(NULL, " \t\n")))
 386                         continue;
 387
 388                 flags[0] = strtoul(p, NULL, 16);
 389
 390                 if (!(p = strtok(NULL, " \t\n")))
 391                         continue;
 392
 393                 flags[1] = strtoul(p, NULL, 16);
 394
 395                 switch (type)
 396                 {
 397                 case FW3_TYPE_DEFAULTS:
 398                         s->defaults.flags[0] = flags[0];
 399                         s->defaults.flags[1] = flags[1];
 400                         break;
 401
 402                 case FW3_TYPE_ZONE:
 403                         if (!(zone = fw3_lookup_zone(state, name, false)))
 404                         {
 405                                 zone = fw3_alloc_zone();
 406
 407                                 if (!zone)
 408                                         continue;
 409
 410                                 zone->name = strdup(name);
 411                                 list_add_tail(&zone->list, &s->zones);
 412
 413                                 setbit(flags[0], FW3_FLAG_DELETED);
 414                         }
 415
 416                         zone->flags[0] = flags[0];
 417                         zone->flags[1] = flags[1];
 418                         list_add_tail(&zone->running_list, &s->running_zones);
 419                         break;
 420
 421                 case FW3_TYPE_IPSET:
 422                         if (!(ipset = fw3_lookup_ipset(state, name, false)))
 423                         {
 424                                 ipset = fw3_alloc_ipset();
 425
 426                                 if (!ipset)
 427                                         continue;
 428
 429                                 ipset->name = strdup(name);
 430                                 list_add_tail(&ipset->list, &s->ipsets);
 431
 432                                 setbit(flags[0], FW3_FLAG_DELETED);
 433                         }
 434
 435                         ipset->flags[0] = flags[0];
 436                         ipset->flags[1] = flags[1];
 437                         list_add_tail(&ipset->running_list, &s->running_ipsets);
 438                         break;
 439
 440                 case FW3_TYPE_NETWORK:
 441                         if (!(zone = fw3_lookup_zone(state, name, false)))
 442                                 continue;
 443
 444                         if (!(p = strtok(NULL, " \t\n")) || !(name = strtok(NULL, " \t\n")))
 445                                 continue;
 446
 447                         if (!(net = malloc(sizeof(*net))))
 448                                 continue;
 449
 450                         memset(net, 0, sizeof(*net));
 451                         snprintf(net->name, sizeof(net->name), "%s", p);
 452                         list_add_tail(&net->list, &zone->running_networks);
 453
 454                         if (!(dev = malloc(sizeof(*dev))))
 455                                 continue;
 456
 457                         memset(dev, 0, sizeof(*dev));
 458                         dev->network = net;
 459                         snprintf(dev->name, sizeof(dev->name), "%s", name);
 460                         list_add_tail(&dev->list, &zone->running_devices);
 461                 }
 462         }
 463
 464         fclose(sf);
 465
 466         return true;
 467 }
 468
 469 void
 470 fw3_write_statefile(void *state)
 471 {
 472         FILE *sf;
 473         struct fw3_state *s = state;
 474         struct fw3_defaults *defs = &s->defaults;
 475         struct fw3_zone *z;
 476         struct fw3_ipset *i;
 477         struct fw3_device *d;
 478
 479         if (fw3_no_table(defs->flags[0]) && fw3_no_table(defs->flags[1]))
 480         {
 481                 if (unlink(FW3_STATEFILE))
 482                         warn("Unable to remove state %s: %s",
 483                              FW3_STATEFILE, strerror(errno));
 484
 485                 return;
 486         }
 487
 488         sf = fopen(FW3_STATEFILE, "w");
 489
 490         if (!sf)
 491         {
 492                 warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 493                 return;
 494         }
 495
 496         fprintf(sf, "%x - %x %x\n",
 497                 FW3_TYPE_DEFAULTS, defs->flags[0], defs->flags[1]);
 498
 499         list_for_each_entry(z, &s->running_zones, running_list)
 500         {
 501                 if (hasbit(z->flags[0], FW3_FLAG_DELETED))
 502                         continue;
 503
 504                 if (fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 505                         continue;
 506
 507                 fprintf(sf, "%x %s %x %x\n",
 508                         FW3_TYPE_ZONE, z->name, z->flags[0], z->flags[1]);
 509
 510                 list_for_each_entry(d, &z->devices, list)
 511                 {
 512                         if (!d->network)
 513                                 continue;
 514
 515                         fprintf(sf, "%x %s 0 0 %s %s\n",
 516                                 FW3_TYPE_NETWORK, z->name, d->network->name, d->name);
 517                 }
 518         }
 519
 520         list_for_each_entry(i, &s->running_ipsets, running_list)
 521         {
 522                 if (hasbit(z->flags[0], FW3_FLAG_DELETED))
 523                         continue;
 524
 525                 if (!fw3_no_family(i->flags[0]) || !fw3_no_family(i->flags[1]))
 526                 {
 527                         fprintf(sf, "%x %s %x %x\n",
 528                                         FW3_TYPE_IPSET, i->name, i->flags[0], i->flags[1]);
 529                 }
 530         }
 531
 532         fclose(sf);
 533 }
 534
 535
 536 struct object_list_heads
 537 {
 538         struct list_head list;
 539         struct list_head running_list;
 540 };
 541
 542 void
 543 fw3_set_running(void *object, struct list_head *dest)
 544 {
 545         struct object_list_heads *o = object;
 546
 547         if (dest && !o->running_list.next)
 548                 list_add_tail(&o->running_list, dest);
 549         else if (!dest && o->running_list.next)
 550                 list_del(&o->running_list);
 551 }
 552
 553 void
 554 fw3_free_object(void *obj, const void *opts)
 555 {
 556         const struct fw3_option *ol;
 557         struct list_head *list, *cur, *tmp;
 558
 559         for (ol = opts; ol->name; ol++)
 560         {
 561                 if (!ol->elem_size)
 562                         continue;
 563
 564                 list = (struct list_head *)((char *)obj + ol->offset);
 565                 list_for_each_safe(cur, tmp, list)
 566                 {
 567                         list_del(cur);
 568                         free(cur);
 569                 }
 570         }
 571
 572         free(obj);
 573 }
 574
 575
 576 bool
 577 fw3_pr_rulespec(int table, int family, uint32_t *flags, uint32_t mask,
 578                 const struct fw3_rule_spec *r, const char *fmt, ...)
 579 {
 580         char buf[256];
 581         bool rv = false;
 582
 583         va_list ap;
 584         uint32_t f = flags ? flags[family == FW3_FAMILY_V6] : 0;
 585
 586         if (mask)
 587                 f &= mask;
 588
 589         for (; r->format; r++)
 590         {
 591                 if (!fw3_is_family(r, family))
 592                         continue;
 593
 594                 if (r->table != table)
 595                         continue;
 596
 597                 if ((r->flag != 0) && !hasbit(f, r->flag))
 598                         continue;
 599
 600                 va_start(ap, fmt);
 601                 vsnprintf(buf, sizeof(buf), r->format, ap);
 602                 va_end(ap);
 603
 604                 fw3_pr(fmt, buf);
 605
 606                 rv = true;
 607         }
 608
 609         return rv;
 610 }
 611
 612
 613 bool
 614 fw3_hotplug(bool add, void *zone, void *device)
 615 {
 616         struct fw3_zone *z = zone;
 617         struct fw3_device *d = device;
 618
 619         if (!d->network)
 620                 return false;
 621
 622         switch (fork())
 623         {
 624         case -1:
 625                 warn("Unable to fork(): %s\n", strerror(errno));
 626                 return false;
 627
 628         case 0:
 629                 break;
 630
 631         default:
 632                 return true;
 633         }
 634
 635         close(0);
 636         close(1);
 637         close(2);
 638         chdir("/");
 639
 640         clearenv();
 641         setenv("ACTION",    add ? "add" : "remove", 1);
 642         setenv("ZONE",      z->name,                1);
 643         setenv("INTERFACE", d->network->name,       1);
 644         setenv("DEVICE",    d->name,                1);
 645
 646         execl(FW3_HOTPLUG, FW3_HOTPLUG, "firewall", NULL);
 647
 648         /* unreached */
 649         return false;
 650 }