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         }
 248
 249         pipe_fd = fdopen(pfds[1], "w");
 250         return true;
 251 }
 252
 253 void
 254 fw3_pr(const char *fmt, ...)
 255 {
 256         va_list args;
 257
 258         if (fw3_pr_debug && pipe_fd != stdout)
 259         {
 260                 va_start(args, fmt);
 261                 vfprintf(stderr, fmt, args);
 262                 va_end(args);
 263         }
 264
 265         va_start(args, fmt);
 266         vfprintf(pipe_fd, fmt, args);
 267         va_end(args);
 268 }
 269
 270 void
 271 fw3_command_close(void)
 272 {
 273         if (pipe_fd && pipe_fd != stdout)
 274                 fclose(pipe_fd);
 275
 276         if (pipe_pid > -1)
 277                 waitpid(pipe_pid, NULL, 0);
 278
 279         signal(SIGPIPE, SIG_DFL);
 280
 281         pipe_fd = NULL;
 282         pipe_pid = -1;
 283 }
 284
 285 bool
 286 fw3_has_table(bool ipv6, const char *table)
 287 {
 288         FILE *f;
 289
 290         char line[12];
 291         bool seen = false;
 292
 293         const char *path = ipv6
 294                 ? "/proc/net/ip6_tables_names" : "/proc/net/ip_tables_names";
 295
 296         if (!(f = fopen(path, "r")))
 297                 return false;
 298
 299         while (fgets(line, sizeof(line), f))
 300         {
 301                 if (!strncmp(line, table, strlen(table)))
 302                 {
 303                         seen = true;
 304                         break;
 305                 }
 306         }
 307
 308         fclose(f);
 309
 310         return seen;
 311 }
 312
 313
 314 bool
 315 fw3_lock(void)
 316 {
 317         lock_fd = open(FW3_LOCKFILE, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 318
 319         if (lock_fd < 0)
 320         {
 321                 warn("Cannot create lock file %s: %s", FW3_LOCKFILE, strerror(errno));
 322                 return false;
 323         }
 324
 325         if (flock(lock_fd, LOCK_EX))
 326         {
 327                 warn("Cannot acquire exclusive lock: %s", strerror(errno));
 328                 return false;
 329         }
 330
 331         return true;
 332 }
 333
 334 void
 335 fw3_unlock(void)
 336 {
 337         if (lock_fd < 0)
 338                 return;
 339
 340         if (flock(lock_fd, LOCK_UN))
 341                 warn("Cannot release exclusive lock: %s", strerror(errno));
 342
 343         close(lock_fd);
 344         unlink(FW3_LOCKFILE);
 345
 346         lock_fd = -1;
 347 }
 348
 349
 350 bool
 351 fw3_read_statefile(void *state)
 352 {
 353         FILE *sf;
 354
 355         int type;
 356         char line[128];
 357         const char *p, *name;
 358
 359         uint32_t flags[2];
 360
 361         struct fw3_state *s = state;
 362         struct fw3_zone *zone;
 363         struct fw3_ipset *ipset;
 364
 365         sf = fopen(FW3_STATEFILE, "r");
 366
 367         if (!sf)
 368                 return false;
 369
 370         while (fgets(line, sizeof(line), sf))
 371         {
 372                 p = strtok(line, " \t\n");
 373
 374                 if (!p)
 375                         continue;
 376
 377                 type = strtoul(p, NULL, 16);
 378                 name = strtok(NULL, " \t\n");
 379
 380                 if (!name)
 381                         continue;
 382
 383                 if (!(p = strtok(NULL, " \t\n")))
 384                         continue;
 385
 386                 flags[0] = strtoul(p, NULL, 16);
 387
 388                 if (!(p = strtok(NULL, " \t\n")))
 389                         continue;
 390
 391                 flags[1] = strtoul(p, NULL, 16);
 392
 393                 switch (type)
 394                 {
 395                 case FW3_TYPE_DEFAULTS:
 396                         s->defaults.flags[0] = flags[0];
 397                         s->defaults.flags[1] = flags[1];
 398                         break;
 399
 400                 case FW3_TYPE_ZONE:
 401                         if (!(zone = fw3_lookup_zone(state, name, false)))
 402                         {
 403                                 zone = fw3_alloc_zone();
 404
 405                                 if (!zone)
 406                                         continue;
 407
 408                                 zone->name = strdup(name);
 409                                 list_add_tail(&zone->list, &s->zones);
 410                         }
 411
 412                         zone->flags[0] = flags[0];
 413                         zone->flags[1] = flags[1];
 414                         list_add_tail(&zone->running_list, &s->running_zones);
 415                         break;
 416
 417                 case FW3_TYPE_IPSET:
 418                         if (!(ipset = fw3_lookup_ipset(state, name, false)))
 419                         {
 420                                 ipset = fw3_alloc_ipset();
 421
 422                                 if (!ipset)
 423                                         continue;
 424
 425                                 ipset->name = strdup(name);
 426                                 list_add_tail(&ipset->list, &s->ipsets);
 427                         }
 428
 429                         ipset->flags[0] = flags[0];
 430                         ipset->flags[1] = flags[1];
 431                         list_add_tail(&ipset->running_list, &s->running_ipsets);
 432                         break;
 433                 }
 434         }
 435
 436         fclose(sf);
 437
 438         return true;
 439 }
 440
 441 void
 442 fw3_write_statefile(void *state)
 443 {
 444         FILE *sf;
 445         struct fw3_state *s = state;
 446         struct fw3_defaults *d = &s->defaults;
 447         struct fw3_zone *z;
 448         struct fw3_ipset *i;
 449
 450         if (fw3_no_table(d->flags[0]) && fw3_no_table(d->flags[1]))
 451         {
 452                 if (unlink(FW3_STATEFILE))
 453                         warn("Unable to remove state %s: %s",
 454                              FW3_STATEFILE, strerror(errno));
 455
 456                 return;
 457         }
 458
 459         sf = fopen(FW3_STATEFILE, "w");
 460
 461         if (!sf)
 462         {
 463                 warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 464                 return;
 465         }
 466
 467         fprintf(sf, "%x - %x %x\n", FW3_TYPE_DEFAULTS, d->flags[0], d->flags[1]);
 468
 469         list_for_each_entry(z, &s->running_zones, running_list)
 470         {
 471                 if (!fw3_no_table(z->flags[0]) || !fw3_no_table(z->flags[1]))
 472                 {
 473                         fprintf(sf, "%x %s %x %x\n",
 474                                         FW3_TYPE_ZONE, z->name, z->flags[0], z->flags[1]);
 475                 }
 476         }
 477
 478         list_for_each_entry(i, &s->running_ipsets, running_list)
 479         {
 480                 if (!fw3_no_family(i->flags[0]) || !fw3_no_family(i->flags[1]))
 481                 {
 482                         fprintf(sf, "%x %s %x %x\n",
 483                                         FW3_TYPE_IPSET, i->name, i->flags[0], i->flags[1]);
 484                 }
 485         }
 486
 487         fclose(sf);
 488 }
 489
 490
 491 struct object_list_heads
 492 {
 493         struct list_head list;
 494         struct list_head running_list;
 495 };
 496
 497 void
 498 fw3_set_running(void *object, struct list_head *dest)
 499 {
 500         struct object_list_heads *o = object;
 501
 502         if (dest && !o->running_list.next)
 503                 list_add_tail(&o->running_list, dest);
 504         else if (!dest && o->running_list.next)
 505                 list_del(&o->running_list);
 506 }
 507
 508 void
 509 fw3_free_object(void *obj, const void *opts)
 510 {
 511         const struct fw3_option *ol;
 512         struct list_head *list, *cur, *tmp;
 513
 514         for (ol = opts; ol->name; ol++)
 515         {
 516                 if (!ol->elem_size)
 517                         continue;
 518
 519                 list = (struct list_head *)((char *)obj + ol->offset);
 520                 list_for_each_safe(cur, tmp, list)
 521                 {
 522                         list_del(cur);
 523                         free(cur);
 524                 }
 525         }
 526
 527         free(obj);
 528 }
 529
 530
 531 bool
 532 fw3_pr_rulespec(int table, int family, uint32_t *flags, uint32_t mask,
 533                 const struct fw3_rule_spec *r, const char *fmt, ...)
 534 {
 535         char buf[256];
 536         bool rv = false;
 537
 538         va_list ap;
 539         uint32_t f = flags ? flags[family == FW3_FAMILY_V6] : 0;
 540
 541         if (mask)
 542                 f &= mask;
 543
 544         for (; r->format; r++)
 545         {
 546                 if (!fw3_is_family(r, family))
 547                         continue;
 548
 549                 if (r->table != table)
 550                         continue;
 551
 552                 if ((r->flag != 0) && !hasbit(f, r->flag))
 553                         continue;
 554
 555                 va_start(ap, fmt);
 556                 vsnprintf(buf, sizeof(buf), r->format, ap);
 557                 va_end(ap);
 558
 559                 fw3_pr(fmt, buf);
 560
 561                 rv = true;
 562         }
 563
 564         return rv;
 565 }