main/tcptls.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 2007 - 2008, Digium, Inc.
   5  *
   6  * Luigi Rizzo (TCP and TLS server code)
   7  * Brett Bryant <brettbryant@gmail.com> (updated for client support)
   8  *
   9  * See http://www.asterisk.org for more information about
  10  * the Asterisk project. Please do not directly contact
  11  * any of the maintainers of this project for assistance;
  12  * the project provides a web site, mailing lists and IRC
  13  * channels for your use.
  14  *
  15  * This program is free software, distributed under the terms of
  16  * the GNU General Public License Version 2. See the LICENSE file
  17  * at the top of the source tree.
  18  */
  19
  20 /*!
  21  * \file
  22  * \brief Code to support TCP and TLS server/client
  23  *
  24  * \author Luigi Rizzo
  25  * \author Brett Bryant <brettbryant@gmail.com>
  26  */
  27
  28 #include "asterisk.h"
  29
  30 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  31
  32 #ifdef HAVE_FCNTL_H
  33 #include <fcntl.h>
  34 #endif
  35
  36 #include <sys/signal.h>
  37
  38 #include "asterisk/compat.h"
  39 #include "asterisk/tcptls.h"
  40 #include "asterisk/http.h"
  41 #include "asterisk/utils.h"
  42 #include "asterisk/strings.h"
  43 #include "asterisk/options.h"
  44 #include "asterisk/manager.h"
  45 #include "asterisk/astobj2.h"
  46
  47 /*! \brief
  48  * replacement read/write functions for SSL support.
  49  * We use wrappers rather than SSL_read/SSL_write directly so
  50  * we can put in some debugging.
  51  */
  52
  53 #ifdef DO_SSL
  54 static HOOK_T ssl_read(void *cookie, char *buf, LEN_T len)
  55 {
  56         int i = SSL_read(cookie, buf, len-1);
  57 #if 0
  58         if (i >= 0)
  59                 buf[i] = '\0';
  60         ast_verb(0, "ssl read size %d returns %d <%s>\n", (int)len, i, buf);
  61 #endif
  62         return i;
  63 }
  64
  65 static HOOK_T ssl_write(void *cookie, const char *buf, LEN_T len)
  66 {
  67 #if 0
  68         char *s = alloca(len+1);
  69         strncpy(s, buf, len);
  70         s[len] = '\0';
  71         ast_verb(0, "ssl write size %d <%s>\n", (int)len, s);
  72 #endif
  73         return SSL_write(cookie, buf, len);
  74 }
  75
  76 static int ssl_close(void *cookie)
  77 {
  78         close(SSL_get_fd(cookie));
  79         SSL_shutdown(cookie);
  80         SSL_free(cookie);
  81         return 0;
  82 }
  83 #endif  /* DO_SSL */
  84
  85 HOOK_T ast_tcptls_server_read(struct ast_tcptls_session_instance *tcptls_session, void *buf, size_t count)
  86 {
  87         if (tcptls_session->fd == -1) {
  88                 ast_log(LOG_ERROR, "server_read called with an fd of -1\n");
  89                 errno = EIO;
  90                 return -1;
  91         }
  92
  93 #ifdef DO_SSL
  94         if (tcptls_session->ssl)
  95                 return ssl_read(tcptls_session->ssl, buf, count);
  96 #endif
  97         return read(tcptls_session->fd, buf, count);
  98 }
  99
 100 HOOK_T ast_tcptls_server_write(struct ast_tcptls_session_instance *tcptls_session, const void *buf, size_t count)
 101 {
 102         if (tcptls_session->fd == -1) {
 103                 ast_log(LOG_ERROR, "server_write called with an fd of -1\n");
 104                 errno = EIO;
 105                 return -1;
 106         }
 107
 108 #ifdef DO_SSL
 109         if (tcptls_session->ssl)
 110                 return ssl_write(tcptls_session->ssl, buf, count);
 111 #endif
 112         return write(tcptls_session->fd, buf, count);
 113 }
 114
 115 static void session_instance_destructor(void *obj)
 116 {
 117         struct ast_tcptls_session_instance *i = obj;
 118         ast_mutex_destroy(&i->lock);
 119 }
 120
 121 /*! \brief
 122 * creates a FILE * from the fd passed by the accept thread.
 123 * This operation is potentially expensive (certificate verification),
 124 * so we do it in the child thread context.
 125 */
 126 static void *handle_tls_connection(void *data)
 127 {
 128         struct ast_tcptls_session_instance *tcptls_session = data;
 129 #ifdef DO_SSL
 130         int (*ssl_setup)(SSL *) = (tcptls_session->client) ? SSL_connect : SSL_accept;
 131         int ret;
 132         char err[256];
 133 #endif
 134
 135         /*
 136         * open a FILE * as appropriate.
 137         */
 138         if (!tcptls_session->parent->tls_cfg)
 139                 tcptls_session->f = fdopen(tcptls_session->fd, "w+");
 140 #ifdef DO_SSL
 141         else if ( (tcptls_session->ssl = SSL_new(tcptls_session->parent->tls_cfg->ssl_ctx)) ) {
 142                 SSL_set_fd(tcptls_session->ssl, tcptls_session->fd);
 143                 if ((ret = ssl_setup(tcptls_session->ssl)) <= 0) {
 144                         ast_verb(2, "Problem setting up ssl connection: %s\n", ERR_error_string(ERR_get_error(), err));
 145                 } else {
 146 #if defined(HAVE_FUNOPEN)       /* the BSD interface */
 147                         tcptls_session->f = funopen(tcptls_session->ssl, ssl_read, ssl_write, NULL, ssl_close);
 148
 149 #elif defined(HAVE_FOPENCOOKIE) /* the glibc/linux interface */
 150                         static const cookie_io_functions_t cookie_funcs = {
 151                                 ssl_read, ssl_write, NULL, ssl_close
 152                         };
 153                         tcptls_session->f = fopencookie(tcptls_session->ssl, "w+", cookie_funcs);
 154 #else
 155                         /* could add other methods here */
 156                         ast_debug(2, "no tcptls_session->f methods attempted!");
 157 #endif
 158                         if ((tcptls_session->client && !ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_DONT_VERIFY_SERVER))
 159                                 || (!tcptls_session->client && ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_VERIFY_CLIENT))) {
 160                                 X509 *peer;
 161                                 long res;
 162                                 peer = SSL_get_peer_certificate(tcptls_session->ssl);
 163                                 if (!peer)
 164                                         ast_log(LOG_WARNING, "No peer SSL certificate\n");
 165                                 res = SSL_get_verify_result(tcptls_session->ssl);
 166                                 if (res != X509_V_OK)
 167                                         ast_log(LOG_ERROR, "Certificate did not verify: %s\n", X509_verify_cert_error_string(res));
 168                                 if (!ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_IGNORE_COMMON_NAME)) {
 169                                         ASN1_STRING *str;
 170                                         unsigned char *str2;
 171                                         X509_NAME *name = X509_get_subject_name(peer);
 172                                         int pos = -1;
 173                                         int found = 0;
 174
 175                                         for (;;) {
 176                                                 /* Walk the certificate to check all available "Common Name" */
 177                                                 /* XXX Probably should do a gethostbyname on the hostname and compare that as well */
 178                                                 pos = X509_NAME_get_index_by_NID(name, NID_commonName, pos);
 179                                                 if (pos < 0)
 180                                                         break;
 181                                                 str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, pos));
 182                                                 ASN1_STRING_to_UTF8(&str2, str);
 183                                                 if (str2) {
 184                                                         if (!strcasecmp(tcptls_session->parent->hostname, (char *) str2))
 185                                                                 found = 1;
 186                                                         ast_debug(3, "SSL Common Name compare s1='%s' s2='%s'\n", tcptls_session->parent->hostname, str2);
 187                                                         OPENSSL_free(str2);
 188                                                 }
 189                                                 if (found)
 190                                                         break;
 191                                         }
 192                                         if (!found) {
 193                                                 ast_log(LOG_ERROR, "Certificate common name did not match (%s)\n", tcptls_session->parent->hostname);
 194                                                 if (peer)
 195                                                         X509_free(peer);
 196                                                 fclose(tcptls_session->f);
 197                                                 return NULL;
 198                                         }
 199                                 }
 200                                 if (peer)
 201                                         X509_free(peer);
 202                         }
 203                 }
 204                 if (!tcptls_session->f) /* no success opening descriptor stacking */
 205                         SSL_free(tcptls_session->ssl);
 206    }
 207 #endif /* DO_SSL */
 208
 209         if (!tcptls_session->f) {
 210                 close(tcptls_session->fd);
 211                 ast_log(LOG_WARNING, "FILE * open failed!\n");
 212                 ao2_ref(tcptls_session, -1);
 213                 return NULL;
 214         }
 215
 216         if (tcptls_session && tcptls_session->parent->worker_fn)
 217                 return tcptls_session->parent->worker_fn(tcptls_session);
 218         else
 219                 return tcptls_session;
 220 }
 221
 222 void *ast_tcptls_server_root(void *data)
 223 {
 224         struct ast_tcptls_session_args *desc = data;
 225         int fd;
 226         struct sockaddr_in sin;
 227         socklen_t sinlen;
 228         struct ast_tcptls_session_instance *tcptls_session;
 229         pthread_t launched;
 230
 231         for (;;) {
 232                 int i, flags;
 233
 234                 if (desc->periodic_fn)
 235                         desc->periodic_fn(desc);
 236                 i = ast_wait_for_input(desc->accept_fd, desc->poll_timeout);
 237                 if (i <= 0)
 238                         continue;
 239                 sinlen = sizeof(sin);
 240                 fd = accept(desc->accept_fd, (struct sockaddr *) &sin, &sinlen);
 241                 if (fd < 0) {
 242                         if ((errno != EAGAIN) && (errno != EINTR))
 243                                 ast_log(LOG_WARNING, "Accept failed: %s\n", strerror(errno));
 244                         continue;
 245                 }
 246                 tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor);
 247                 if (!tcptls_session) {
 248                         ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
 249                         close(fd);
 250                         continue;
 251                 }
 252
 253                 ast_mutex_init(&tcptls_session->lock);
 254
 255                 flags = fcntl(fd, F_GETFL);
 256                 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
 257                 tcptls_session->fd = fd;
 258                 tcptls_session->parent = desc;
 259                 memcpy(&tcptls_session->remote_address, &sin, sizeof(tcptls_session->remote_address));
 260
 261                 tcptls_session->client = 0;
 262
 263                 if (ast_pthread_create_detached_background(&launched, NULL, handle_tls_connection, tcptls_session)) {
 264                         ast_log(LOG_WARNING, "Unable to launch helper thread: %s\n", strerror(errno));
 265                         close(tcptls_session->fd);
 266                         ao2_ref(tcptls_session, -1);
 267                 }
 268         }
 269         return NULL;
 270 }
 271
 272 static int __ssl_setup(struct ast_tls_config *cfg, int client)
 273 {
 274 #ifndef DO_SSL
 275         cfg->enabled = 0;
 276         return 0;
 277 #else
 278         if (!cfg->enabled)
 279                 return 0;
 280
 281         SSL_load_error_strings();
 282         SSLeay_add_ssl_algorithms();
 283
 284         if (!(cfg->ssl_ctx = SSL_CTX_new( client ? SSLv23_client_method() : SSLv23_server_method() ))) {
 285                 ast_debug(1, "Sorry, SSL_CTX_new call returned null...\n");
 286                 cfg->enabled = 0;
 287                 return 0;
 288         }
 289         if (!ast_strlen_zero(cfg->certfile)) {
 290                 if (SSL_CTX_use_certificate_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
 291                     SSL_CTX_use_PrivateKey_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
 292                     SSL_CTX_check_private_key(cfg->ssl_ctx) == 0 ) {
 293                         if (!client) {
 294                                 /* Clients don't need a certificate, but if its setup we can use it */
 295                                 ast_verb(0, "SSL cert error <%s>", cfg->certfile);
 296                                 sleep(2);
 297                                 cfg->enabled = 0;
 298                                 return 0;
 299                         }
 300                 }
 301         }
 302         if (!ast_strlen_zero(cfg->cipher)) {
 303                 if (SSL_CTX_set_cipher_list(cfg->ssl_ctx, cfg->cipher) == 0 ) {
 304                         if (!client) {
 305                                 ast_verb(0, "SSL cipher error <%s>", cfg->cipher);
 306                                 sleep(2);
 307                                 cfg->enabled = 0;
 308                                 return 0;
 309                         }
 310                 }
 311         }
 312         if (!ast_strlen_zero(cfg->cafile) || !ast_strlen_zero(cfg->capath)) {
 313                 if (SSL_CTX_load_verify_locations(cfg->ssl_ctx, S_OR(cfg->cafile, NULL), S_OR(cfg->capath,NULL)) == 0)
 314                         ast_verb(0, "SSL CA file(%s)/path(%s) error\n", cfg->cafile, cfg->capath);
 315         }
 316
 317         ast_verb(0, "SSL certificate ok\n");
 318         return 1;
 319 #endif
 320 }
 321
 322 int ast_ssl_setup(struct ast_tls_config *cfg)
 323 {
 324         return __ssl_setup(cfg, 0);
 325 }
 326
 327 /*! \brief A generic client routine for a TCP client
 328  *  and starts a thread for handling accept()
 329  */
 330 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct ast_tcptls_session_args *desc)
 331 {
 332         int flags;
 333         int x = 1;
 334         struct ast_tcptls_session_instance *tcptls_session = NULL;
 335
 336         /* Do nothing if nothing has changed */
 337         if (!memcmp(&desc->old_address, &desc->remote_address, sizeof(desc->old_address))) {
 338                 ast_debug(1, "Nothing changed in %s\n", desc->name);
 339                 return NULL;
 340         }
 341
 342         desc->old_address = desc->remote_address;
 343
 344         if (desc->accept_fd != -1)
 345                 close(desc->accept_fd);
 346
 347         desc->accept_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 348         if (desc->accept_fd < 0) {
 349                 ast_log(LOG_WARNING, "Unable to allocate socket for %s: %s\n",
 350                         desc->name, strerror(errno));
 351                 return NULL;
 352         }
 353
 354         /* if a local address was specified, bind to it so the connection will
 355            originate from the desired address */
 356         if (desc->local_address.sin_family != 0) {
 357                 setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
 358                 if (bind(desc->accept_fd, (struct sockaddr *) &desc->local_address, sizeof(desc->local_address))) {
 359                         ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
 360                         desc->name,
 361                                 ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
 362                                 strerror(errno));
 363                         goto error;
 364                 }
 365         }
 366
 367         if (connect(desc->accept_fd, (const struct sockaddr *) &desc->remote_address, sizeof(desc->remote_address))) {
 368                 ast_log(LOG_ERROR, "Unable to connect %s to %s:%d: %s\n",
 369                         desc->name,
 370                         ast_inet_ntoa(desc->remote_address.sin_addr), ntohs(desc->remote_address.sin_port),
 371                         strerror(errno));
 372                 goto error;
 373         }
 374
 375         if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor)))
 376                 goto error;
 377
 378         ast_mutex_init(&tcptls_session->lock);
 379
 380         flags = fcntl(desc->accept_fd, F_GETFL);
 381         fcntl(desc->accept_fd, F_SETFL, flags & ~O_NONBLOCK);
 382
 383         tcptls_session->fd = desc->accept_fd;
 384         tcptls_session->parent = desc;
 385         tcptls_session->parent->worker_fn = NULL;
 386         memcpy(&tcptls_session->remote_address, &desc->remote_address, sizeof(tcptls_session->remote_address));
 387
 388         tcptls_session->client = 1;
 389
 390         if (desc->tls_cfg) {
 391                 desc->tls_cfg->enabled = 1;
 392                 __ssl_setup(desc->tls_cfg, 1);
 393         }
 394
 395         ao2_ref(tcptls_session, +1);
 396         if (!handle_tls_connection(tcptls_session))
 397                 goto error;
 398
 399         return tcptls_session;
 400
 401 error:
 402         close(desc->accept_fd);
 403         desc->accept_fd = -1;
 404         if (tcptls_session)
 405                 ao2_ref(tcptls_session, -1);
 406         return NULL;
 407 }
 408
 409 /*! \brief
 410  * This is a generic (re)start routine for a TCP server,
 411  * which does the socket/bind/listen and starts a thread for handling
 412  * accept().
 413  */
 414 void ast_tcptls_server_start(struct ast_tcptls_session_args *desc)
 415 {
 416         int flags;
 417         int x = 1;
 418
 419         /* Do nothing if nothing has changed */
 420         if (!memcmp(&desc->old_address, &desc->local_address, sizeof(desc->old_address))) {
 421                 ast_debug(1, "Nothing changed in %s\n", desc->name);
 422                 return;
 423         }
 424
 425         desc->old_address = desc->local_address;
 426
 427         /* Shutdown a running server if there is one */
 428         if (desc->master != AST_PTHREADT_NULL) {
 429                 pthread_cancel(desc->master);
 430                 pthread_kill(desc->master, SIGURG);
 431                 pthread_join(desc->master, NULL);
 432         }
 433
 434         if (desc->accept_fd != -1)
 435                 close(desc->accept_fd);
 436
 437         /* If there's no new server, stop here */
 438         if (desc->local_address.sin_family == 0) {
 439                 ast_debug(2, "Server disabled:  %s\n", desc->name);
 440                 return;
 441         }
 442
 443         desc->accept_fd = socket(AF_INET, SOCK_STREAM, 0);
 444         if (desc->accept_fd < 0) {
 445                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n", desc->name, strerror(errno));
 446                 return;
 447         }
 448
 449         setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
 450         if (bind(desc->accept_fd, (struct sockaddr *) &desc->local_address, sizeof(desc->local_address))) {
 451                 ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
 452                         desc->name,
 453                         ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
 454                         strerror(errno));
 455                 goto error;
 456         }
 457         if (listen(desc->accept_fd, 10)) {
 458                 ast_log(LOG_ERROR, "Unable to listen for %s!\n", desc->name);
 459                 goto error;
 460         }
 461         flags = fcntl(desc->accept_fd, F_GETFL);
 462         fcntl(desc->accept_fd, F_SETFL, flags | O_NONBLOCK);
 463         if (ast_pthread_create_background(&desc->master, NULL, desc->accept_fn, desc)) {
 464                 ast_log(LOG_ERROR, "Unable to launch thread for %s on %s:%d: %s\n",
 465                         desc->name,
 466                         ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
 467                         strerror(errno));
 468                 goto error;
 469         }
 470         return;
 471
 472 error:
 473         close(desc->accept_fd);
 474         desc->accept_fd = -1;
 475 }
 476
 477 /*! \brief Shutdown a running server if there is one */
 478 void ast_tcptls_server_stop(struct ast_tcptls_session_args *desc)
 479 {
 480         if (desc->master != AST_PTHREADT_NULL) {
 481                 pthread_cancel(desc->master);
 482                 pthread_kill(desc->master, SIGURG);
 483                 pthread_join(desc->master, NULL);
 484         }
 485         if (desc->accept_fd != -1)
 486                 close(desc->accept_fd);
 487         desc->accept_fd = -1;
 488         ast_debug(2, "Stopped server :: %s\n", desc->name);
 489 }