main/acl.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2006, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief Various sorts of access control
  22  *
  23  * \author Mark Spencer <markster@digium.com>
  24  */
  25
  26 #include "asterisk.h"
  27
  28 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  29
  30 #include "asterisk/network.h"
  31
  32 #if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__Darwin__)
  33 #include <fcntl.h>
  34 #include <net/route.h>
  35 #endif
  36
  37 #if defined(SOLARIS)
  38 #include <sys/sockio.h>
  39 #include <net/if.h>
  40 #elif defined(HAVE_GETIFADDRS)
  41 #include <ifaddrs.h>
  42 #endif
  43
  44 #include "asterisk/acl.h"
  45 #include "asterisk/channel.h"
  46 #include "asterisk/utils.h"
  47 #include "asterisk/lock.h"
  48 #include "asterisk/srv.h"
  49
  50 #if (!defined(SOLARIS) && !defined(HAVE_GETIFADDRS))
  51 static int get_local_address(struct in_addr *ourip)
  52 {
  53         return -1;
  54 }
  55 #else
  56 static void score_address(const struct sockaddr_in *sin, struct in_addr *best_addr, int *best_score)
  57 {
  58         const char *address;
  59         int score;
  60
  61         address = ast_inet_ntoa(sin->sin_addr);
  62
  63         /* RFC 1700 alias for the local network */
  64         if (address[0] == '0')
  65                 score = -25;
  66         /* RFC 1700 localnet */
  67         else if (strncmp(address, "127", 3) == 0)
  68                 score = -20;
  69         /* RFC 1918 non-public address space */
  70         else if (strncmp(address, "10.", 3) == 0)
  71                 score = -5;
  72         /* RFC 1918 non-public address space */
  73         else if (strncmp(address, "172", 3) == 0) {
  74                 /* 172.16.0.0 - 172.19.255.255, but not 172.160.0.0 - 172.169.255.255 */
  75                 if (address[4] == '1' && address[5] >= '6' && address[6] == '.')
  76                         score = -5;
  77                 /* 172.20.0.0 - 172.29.255.255, but not 172.200.0.0 - 172.255.255.255 nor 172.2.0.0 - 172.2.255.255 */
  78                 else if (address[4] == '2' && address[6] == '.')
  79                         score = -5;
  80                 /* 172.30.0.0 - 172.31.255.255 */
  81                 else if (address[4] == '3' && address[5] <= '1')
  82                         score = -5;
  83                 /* All other 172 addresses are public */
  84                 else
  85                         score = 0;
  86         /* RFC 2544 Benchmark test range */
  87         } else if (strncmp(address, "198.1", 5) == 0 && address[5] >= '8' && address[6] == '.')
  88                 score = -10;
  89         /* RFC 1918 non-public address space */
  90         else if (strncmp(address, "192.168", 7) == 0)
  91                 score = -5;
  92         /* RFC 3330 Zeroconf network */
  93         else if (strncmp(address, "169.254", 7) == 0)
  94                 /*!\note Better score than a test network, but not quite as good as RFC 1918
  95                  * address space.  The reason is that some Linux distributions automatically
  96                  * configure a Zeroconf address before trying DHCP, so we want to prefer a
  97                  * DHCP lease to a Zeroconf address.
  98                  */
  99                 score = -10;
 100         /* RFC 3330 Test network */
 101         else if (strncmp(address, "192.0.2.", 8) == 0)
 102                 score = -15;
 103         /* Every other address should be publically routable */
 104         else
 105                 score = 0;
 106
 107         if (score > *best_score) {
 108                 *best_score = score;
 109                 memcpy(best_addr, &sin->sin_addr, sizeof(*best_addr));
 110         }
 111 }
 112
 113 static int get_local_address(struct in_addr *ourip)
 114 {
 115         int s, res = -1;
 116 #ifdef SOLARIS
 117         struct lifreq *ifr = NULL;
 118         struct lifnum ifn;
 119         struct lifconf ifc;
 120         struct sockaddr_in *sa;
 121         char *buf = NULL;
 122         int bufsz, x;
 123 #endif /* SOLARIS */
 124 #if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
 125         struct ifaddrs *ifap, *ifaphead;
 126         int rtnerr;
 127         const struct sockaddr_in *sin;
 128 #endif /* BSD_OR_LINUX */
 129         struct in_addr best_addr;
 130         int best_score = -100;
 131         memset(&best_addr, 0, sizeof(best_addr));
 132
 133 #if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
 134         rtnerr = getifaddrs(&ifaphead);
 135         if (rtnerr) {
 136                 perror(NULL);
 137                 return -1;
 138         }
 139 #endif /* BSD_OR_LINUX */
 140
 141         s = socket(AF_INET, SOCK_STREAM, 0);
 142
 143         if (s > 0) {
 144 #if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
 145                 for (ifap = ifaphead; ifap; ifap = ifap->ifa_next) {
 146
 147                         if (ifap->ifa_addr && ifap->ifa_addr->sa_family == AF_INET) {
 148                                 sin = (const struct sockaddr_in *) ifap->ifa_addr;
 149                                 score_address(sin, &best_addr, &best_score);
 150                                 res = 0;
 151
 152                                 if (best_score == 0)
 153                                         break;
 154                         }
 155                 }
 156 #endif /* BSD_OR_LINUX */
 157
 158                 /* There is no reason whatsoever that this shouldn't work on Linux or BSD also. */
 159 #ifdef SOLARIS
 160                 /* Get a count of interfaces on the machine */
 161                 ifn.lifn_family = AF_INET;
 162                 ifn.lifn_flags = 0;
 163                 ifn.lifn_count = 0;
 164                 if (ioctl(s, SIOCGLIFNUM, &ifn) < 0) {
 165                         close(s);
 166                         return -1;
 167                 }
 168
 169                 bufsz = ifn.lifn_count * sizeof(struct lifreq);
 170                 if (!(buf = malloc(bufsz))) {
 171                         close(s);
 172                         return -1;
 173                 }
 174                 memset(buf, 0, bufsz);
 175
 176                 /* Get a list of interfaces on the machine */
 177                 ifc.lifc_len = bufsz;
 178                 ifc.lifc_buf = buf;
 179                 ifc.lifc_family = AF_INET;
 180                 ifc.lifc_flags = 0;
 181                 if (ioctl(s, SIOCGLIFCONF, &ifc) < 0) {
 182                         close(s);
 183                         free(buf);
 184                         return -1;
 185                 }
 186
 187                 for (ifr = (struct lifreq *)buf, x = 0; x < ifn.lifn_count; ifr++, x++) {
 188                         sa = (struct sockaddr_in *)&(ifr->lifr_addr);
 189                         score_address(sa, &best_addr, &best_score);
 190                         res = 0;
 191
 192                         if (best_score == 0)
 193                                 break;
 194                 }
 195
 196                 free(buf);
 197 #endif /* SOLARIS */
 198
 199                 close(s);
 200         }
 201 #if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__linux__) || defined(__Darwin__)
 202         freeifaddrs(ifaphead);
 203 #endif /* BSD_OR_LINUX */
 204
 205         if (res == 0 && ourip)
 206                 memcpy(ourip, &best_addr, sizeof(*ourip));
 207         return res;
 208 }
 209 #endif /* HAVE_GETIFADDRS */
 210
 211 /* Free HA structure */
 212 void ast_free_ha(struct ast_ha *ha)
 213 {
 214         struct ast_ha *hal;
 215         while (ha) {
 216                 hal = ha;
 217                 ha = ha->next;
 218                 ast_free(hal);
 219         }
 220 }
 221
 222 /* Copy HA structure */
 223 static void ast_copy_ha(struct ast_ha *from, struct ast_ha *to)
 224 {
 225         memcpy(&to->netaddr, &from->netaddr, sizeof(from->netaddr));
 226         memcpy(&to->netmask, &from->netmask, sizeof(from->netmask));
 227         to->sense = from->sense;
 228 }
 229
 230 /* Create duplicate of ha structure */
 231 static struct ast_ha *ast_duplicate_ha(struct ast_ha *original)
 232 {
 233         struct ast_ha *new_ha;
 234
 235         if ((new_ha = ast_malloc(sizeof(*new_ha)))) {
 236                 /* Copy from original to new object */
 237                 ast_copy_ha(original, new_ha);
 238         }
 239
 240         return new_ha;
 241 }
 242
 243 /* Create duplicate HA link list */
 244 /*  Used in chan_sip2 templates */
 245 struct ast_ha *ast_duplicate_ha_list(struct ast_ha *original)
 246 {
 247         struct ast_ha *start = original;
 248         struct ast_ha *ret = NULL;
 249         struct ast_ha *link, *prev = NULL;
 250
 251         while (start) {
 252                 link = ast_duplicate_ha(start);  /* Create copy of this object */
 253                 if (prev)
 254                         prev->next = link;              /* Link previous to this object */
 255
 256                 if (!ret)
 257                         ret = link;             /* Save starting point */
 258
 259                 start = start->next;            /* Go to next object */
 260                 prev = link;                    /* Save pointer to this object */
 261         }
 262         return ret;                     /* Return start of list */
 263 }
 264
 265 struct ast_ha *ast_append_ha(const char *sense, const char *stuff, struct ast_ha *path, int *error)
 266 {
 267         struct ast_ha *ha;
 268         char *nm;
 269         struct ast_ha *prev = NULL;
 270         struct ast_ha *ret;
 271         int x;
 272         char *tmp = ast_strdupa(stuff);
 273
 274         ret = path;
 275         while (path) {
 276                 prev = path;
 277                 path = path->next;
 278         }
 279
 280         ha = ast_malloc(sizeof(*ha));
 281         if (!ha)
 282                 return ret;
 283
 284         nm = strchr(tmp, '/');
 285         if (!nm) {
 286                 /* assume /32. Yes, htonl does not do anything for this particular mask
 287                    but we better use it to show we remember about byte order */
 288                 ha->netmask.s_addr = htonl(0xFFFFFFFF);
 289         } else {
 290                 *nm = '\0';
 291                 nm++;
 292
 293                 if (!strchr(nm, '.')) {
 294                         if ((sscanf(nm, "%d", &x) == 1) && (x >= 0) && (x <= 32))
 295                                 ha->netmask.s_addr = htonl(0xFFFFFFFF << (32 - x));
 296                         else {
 297                                 ast_log(LOG_WARNING, "Invalid CIDR in %s\n", stuff);
 298                                 ast_free(ha);
 299                                 if (error)
 300                                         *error = 1;
 301                                 return ret;
 302                         }
 303                 } else if (!inet_aton(nm, &ha->netmask)) {
 304                         ast_log(LOG_WARNING, "Invalid mask in %s\n", stuff);
 305                         ast_free(ha);
 306                         if (error)
 307                                 *error = 1;
 308                         return ret;
 309                 }
 310         }
 311
 312         if (!inet_aton(tmp, &ha->netaddr)) {
 313                 ast_log(LOG_WARNING, "Invalid IP address in %s\n", stuff);
 314                 ast_free(ha);
 315                 if (error)
 316                         *error = 1;
 317                 return ret;
 318         }
 319
 320         ha->netaddr.s_addr &= ha->netmask.s_addr;
 321
 322         ha->sense = strncasecmp(sense, "p", 1) ? AST_SENSE_DENY : AST_SENSE_ALLOW;
 323
 324         ha->next = NULL;
 325         if (prev) {
 326                 prev->next = ha;
 327         } else {
 328                 ret = ha;
 329         }
 330
 331         ast_debug(1, "%s/%s sense %d appended to acl for peer\n", ast_strdupa(ast_inet_ntoa(ha->netaddr)), ast_strdupa(ast_inet_ntoa(ha->netmask)), ha->sense);
 332
 333         return ret;
 334 }
 335
 336 int ast_apply_ha(struct ast_ha *ha, struct sockaddr_in *sin)
 337 {
 338         /* Start optimistic */
 339         int res = AST_SENSE_ALLOW;
 340         while (ha) {
 341 #if 0   /* debugging code */
 342                 char iabuf[INET_ADDRSTRLEN];
 343                 char iabuf2[INET_ADDRSTRLEN];
 344                 /* DEBUG */
 345                 ast_copy_string(iabuf, ast_inet_ntoa(sin->sin_addr), sizeof(iabuf));
 346                 ast_copy_string(iabuf2, ast_inet_ntoa(ha->netaddr), sizeof(iabuf2));
 347                 ast_debug(1, "##### Testing %s with %s\n", iabuf, iabuf2);
 348 #endif
 349                 /* For each rule, if this address and the netmask = the net address
 350                    apply the current rule */
 351                 if ((sin->sin_addr.s_addr & ha->netmask.s_addr) == ha->netaddr.s_addr)
 352                         res = ha->sense;
 353                 ha = ha->next;
 354         }
 355         return res;
 356 }
 357
 358 int ast_get_ip_or_srv(struct sockaddr_in *sin, const char *value, const char *service)
 359 {
 360         struct hostent *hp;
 361         struct ast_hostent ahp;
 362         char srv[256];
 363         char host[256];
 364         int tportno = ntohs(sin->sin_port);
 365         if (service) {
 366                 snprintf(srv, sizeof(srv), "%s.%s", service, value);
 367                 if (ast_get_srv(NULL, host, sizeof(host), &tportno, srv) > 0) {
 368                         sin->sin_port = htons(tportno);
 369                         value = host;
 370                 }
 371         }
 372         hp = ast_gethostbyname(value, &ahp);
 373         if (hp) {
 374                 memcpy(&sin->sin_addr, hp->h_addr, sizeof(sin->sin_addr));
 375         } else {
 376                 ast_log(LOG_WARNING, "Unable to lookup '%s'\n", value);
 377                 return -1;
 378         }
 379         return 0;
 380 }
 381
 382 struct dscp_codepoint {
 383         char *name;
 384         unsigned int space;
 385 };
 386
 387 /* IANA registered DSCP codepoints */
 388
 389 static const struct dscp_codepoint dscp_pool1[] = {
 390         { "CS0", 0x00 },
 391         { "CS1", 0x08 },
 392         { "CS2", 0x10 },
 393         { "CS3", 0x18 },
 394         { "CS4", 0x20 },
 395         { "CS5", 0x28 },
 396         { "CS6", 0x30 },
 397         { "CS7", 0x38 },
 398         { "AF11", 0x0A },
 399         { "AF12", 0x0C },
 400         { "AF13", 0x0E },
 401         { "AF21", 0x12 },
 402         { "AF22", 0x14 },
 403         { "AF23", 0x16 },
 404         { "AF31", 0x1A },
 405         { "AF32", 0x1C },
 406         { "AF33", 0x1E },
 407         { "AF41", 0x22 },
 408         { "AF42", 0x24 },
 409         { "AF43", 0x26 },
 410         { "EF", 0x2E },
 411 };
 412
 413 int ast_str2cos(const char *value, unsigned int *cos)
 414 {
 415         int fval;
 416
 417         if (sscanf(value, "%d", &fval) == 1) {
 418                 if (fval < 8) {
 419                     *cos = fval;
 420                     return 0;
 421                 }
 422         }
 423
 424         return -1;
 425 }
 426
 427 int ast_str2tos(const char *value, unsigned int *tos)
 428 {
 429         int fval;
 430         unsigned int x;
 431
 432         if (sscanf(value, "%i", &fval) == 1) {
 433                 *tos = fval & 0xFF;
 434                 return 0;
 435         }
 436
 437         for (x = 0; x < sizeof(dscp_pool1) / sizeof(dscp_pool1[0]); x++) {
 438                 if (!strcasecmp(value, dscp_pool1[x].name)) {
 439                         *tos = dscp_pool1[x].space << 2;
 440                         return 0;
 441                 }
 442         }
 443
 444         return -1;
 445 }
 446
 447 const char *ast_tos2str(unsigned int tos)
 448 {
 449         unsigned int x;
 450
 451         for (x = 0; x < sizeof(dscp_pool1) / sizeof(dscp_pool1[0]); x++) {
 452                 if (dscp_pool1[x].space == (tos >> 2))
 453                         return dscp_pool1[x].name;
 454         }
 455
 456         return "unknown";
 457 }
 458
 459 int ast_get_ip(struct sockaddr_in *sin, const char *value)
 460 {
 461         return ast_get_ip_or_srv(sin, value, NULL);
 462 }
 463
 464 int ast_ouraddrfor(struct in_addr *them, struct in_addr *us)
 465 {
 466         int s;
 467         struct sockaddr_in sin;
 468         socklen_t slen;
 469
 470         s = socket(PF_INET, SOCK_DGRAM, 0);
 471         if (s < 0) {
 472                 ast_log(LOG_ERROR, "Cannot create socket\n");
 473                 return -1;
 474         }
 475         sin.sin_family = AF_INET;
 476         sin.sin_port = 5060;
 477         sin.sin_addr = *them;
 478         if (connect(s, (struct sockaddr *)&sin, sizeof(sin))) {
 479                 ast_log(LOG_WARNING, "Cannot connect\n");
 480                 close(s);
 481                 return -1;
 482         }
 483         slen = sizeof(sin);
 484         if (getsockname(s, (struct sockaddr *)&sin, &slen)) {
 485                 ast_log(LOG_WARNING, "Cannot get socket name\n");
 486                 close(s);
 487                 return -1;
 488         }
 489         close(s);
 490         ast_debug(3, "Found IP address for this socket\n");
 491         *us = sin.sin_addr;
 492         return 0;
 493 }
 494
 495 int ast_find_ourip(struct in_addr *ourip, struct sockaddr_in bindaddr)
 496 {
 497         char ourhost[MAXHOSTNAMELEN] = "";
 498         struct ast_hostent ahp;
 499         struct hostent *hp;
 500         struct in_addr saddr;
 501
 502         /* just use the bind address if it is nonzero */
 503         if (ntohl(bindaddr.sin_addr.s_addr)) {
 504                 memcpy(ourip, &bindaddr.sin_addr, sizeof(*ourip));
 505                 ast_debug(3, "Attached to given IP address\n");
 506                 return 0;
 507         }
 508         /* try to use our hostname */
 509         if (gethostname(ourhost, sizeof(ourhost) - 1)) {
 510                 ast_log(LOG_WARNING, "Unable to get hostname\n");
 511         } else {
 512                 hp = ast_gethostbyname(ourhost, &ahp);
 513                 if (hp) {
 514                         memcpy(ourip, hp->h_addr, sizeof(*ourip));
 515                         ast_debug(3, "Found one IP address based on local hostname %s.\n", ourhost);
 516                         return 0;
 517                 }
 518         }
 519         ast_debug(3, "Trying to check A.ROOT-SERVERS.NET and get our IP address for that connection\n");
 520         /* A.ROOT-SERVERS.NET. */
 521         if (inet_aton("198.41.0.4", &saddr) && !ast_ouraddrfor(&saddr, ourip))
 522                 return 0;
 523         return get_local_address(ourip);
 524 }
 525