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                 setvbuf(tcptls_session->f, NULL, _IONBF, 0);
 141         }
 142 #ifdef DO_SSL
 143         else if ( (tcptls_session->ssl = SSL_new(tcptls_session->parent->tls_cfg->ssl_ctx)) ) {
 144                 SSL_set_fd(tcptls_session->ssl, tcptls_session->fd);
 145                 if ((ret = ssl_setup(tcptls_session->ssl)) <= 0) {
 146                         ast_verb(2, "Problem setting up ssl connection: %s\n", ERR_error_string(ERR_get_error(), err));
 147                 } else {
 148 #if defined(HAVE_FUNOPEN)       /* the BSD interface */
 149                         tcptls_session->f = funopen(tcptls_session->ssl, ssl_read, ssl_write, NULL, ssl_close);
 150
 151 #elif defined(HAVE_FOPENCOOKIE) /* the glibc/linux interface */
 152                         static const cookie_io_functions_t cookie_funcs = {
 153                                 ssl_read, ssl_write, NULL, ssl_close
 154                         };
 155                         tcptls_session->f = fopencookie(tcptls_session->ssl, "w+", cookie_funcs);
 156 #else
 157                         /* could add other methods here */
 158                         ast_debug(2, "no tcptls_session->f methods attempted!");
 159 #endif
 160                         if ((tcptls_session->client && !ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_DONT_VERIFY_SERVER))
 161                                 || (!tcptls_session->client && ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_VERIFY_CLIENT))) {
 162                                 X509 *peer;
 163                                 long res;
 164                                 peer = SSL_get_peer_certificate(tcptls_session->ssl);
 165                                 if (!peer)
 166                                         ast_log(LOG_WARNING, "No peer SSL certificate\n");
 167                                 res = SSL_get_verify_result(tcptls_session->ssl);
 168                                 if (res != X509_V_OK)
 169                                         ast_log(LOG_ERROR, "Certificate did not verify: %s\n", X509_verify_cert_error_string(res));
 170                                 if (!ast_test_flag(&tcptls_session->parent->tls_cfg->flags, AST_SSL_IGNORE_COMMON_NAME)) {
 171                                         ASN1_STRING *str;
 172                                         unsigned char *str2;
 173                                         X509_NAME *name = X509_get_subject_name(peer);
 174                                         int pos = -1;
 175                                         int found = 0;
 176
 177                                         for (;;) {
 178                                                 /* Walk the certificate to check all available "Common Name" */
 179                                                 /* XXX Probably should do a gethostbyname on the hostname and compare that as well */
 180                                                 pos = X509_NAME_get_index_by_NID(name, NID_commonName, pos);
 181                                                 if (pos < 0)
 182                                                         break;
 183                                                 str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, pos));
 184                                                 ASN1_STRING_to_UTF8(&str2, str);
 185                                                 if (str2) {
 186                                                         if (!strcasecmp(tcptls_session->parent->hostname, (char *) str2))
 187                                                                 found = 1;
 188                                                         ast_debug(3, "SSL Common Name compare s1='%s' s2='%s'\n", tcptls_session->parent->hostname, str2);
 189                                                         OPENSSL_free(str2);
 190                                                 }
 191                                                 if (found)
 192                                                         break;
 193                                         }
 194                                         if (!found) {
 195                                                 ast_log(LOG_ERROR, "Certificate common name did not match (%s)\n", tcptls_session->parent->hostname);
 196                                                 if (peer)
 197                                                         X509_free(peer);
 198                                                 fclose(tcptls_session->f);
 199                                                 return NULL;
 200                                         }
 201                                 }
 202                                 if (peer)
 203                                         X509_free(peer);
 204                         }
 205                 }
 206                 if (!tcptls_session->f) /* no success opening descriptor stacking */
 207                         SSL_free(tcptls_session->ssl);
 208    }
 209 #endif /* DO_SSL */
 210
 211         if (!tcptls_session->f) {
 212                 close(tcptls_session->fd);
 213                 ast_log(LOG_WARNING, "FILE * open failed!\n");
 214                 ao2_ref(tcptls_session, -1);
 215                 return NULL;
 216         }
 217
 218         if (tcptls_session && tcptls_session->parent->worker_fn)
 219                 return tcptls_session->parent->worker_fn(tcptls_session);
 220         else
 221                 return tcptls_session;
 222 }
 223
 224 void *ast_tcptls_server_root(void *data)
 225 {
 226         struct ast_tcptls_session_args *desc = data;
 227         int fd;
 228         struct sockaddr_in sin;
 229         socklen_t sinlen;
 230         struct ast_tcptls_session_instance *tcptls_session;
 231         pthread_t launched;
 232
 233         for (;;) {
 234                 int i, flags;
 235
 236                 if (desc->periodic_fn)
 237                         desc->periodic_fn(desc);
 238                 i = ast_wait_for_input(desc->accept_fd, desc->poll_timeout);
 239                 if (i <= 0)
 240                         continue;
 241                 sinlen = sizeof(sin);
 242                 fd = accept(desc->accept_fd, (struct sockaddr *) &sin, &sinlen);
 243                 if (fd < 0) {
 244                         if ((errno != EAGAIN) && (errno != EINTR))
 245                                 ast_log(LOG_WARNING, "Accept failed: %s\n", strerror(errno));
 246                         continue;
 247                 }
 248                 tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor);
 249                 if (!tcptls_session) {
 250                         ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
 251                         close(fd);
 252                         continue;
 253                 }
 254
 255                 ast_mutex_init(&tcptls_session->lock);
 256
 257                 flags = fcntl(fd, F_GETFL);
 258                 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
 259                 tcptls_session->fd = fd;
 260                 tcptls_session->parent = desc;
 261                 memcpy(&tcptls_session->remote_address, &sin, sizeof(tcptls_session->remote_address));
 262
 263                 tcptls_session->client = 0;
 264
 265                 if (ast_pthread_create_detached_background(&launched, NULL, handle_tls_connection, tcptls_session)) {
 266                         ast_log(LOG_WARNING, "Unable to launch helper thread: %s\n", strerror(errno));
 267                         close(tcptls_session->fd);
 268                         ao2_ref(tcptls_session, -1);
 269                 }
 270         }
 271         return NULL;
 272 }
 273
 274 static int __ssl_setup(struct ast_tls_config *cfg, int client)
 275 {
 276 #ifndef DO_SSL
 277         cfg->enabled = 0;
 278         return 0;
 279 #else
 280         if (!cfg->enabled)
 281                 return 0;
 282
 283         SSL_load_error_strings();
 284         SSLeay_add_ssl_algorithms();
 285
 286         if (!(cfg->ssl_ctx = SSL_CTX_new( client ? SSLv23_client_method() : SSLv23_server_method() ))) {
 287                 ast_debug(1, "Sorry, SSL_CTX_new call returned null...\n");
 288                 cfg->enabled = 0;
 289                 return 0;
 290         }
 291         if (!ast_strlen_zero(cfg->certfile)) {
 292                 if (SSL_CTX_use_certificate_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
 293                     SSL_CTX_use_PrivateKey_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
 294                     SSL_CTX_check_private_key(cfg->ssl_ctx) == 0 ) {
 295                         if (!client) {
 296                                 /* Clients don't need a certificate, but if its setup we can use it */
 297                                 ast_verb(0, "SSL cert error <%s>", cfg->certfile);
 298                                 sleep(2);
 299                                 cfg->enabled = 0;
 300                                 return 0;
 301                         }
 302                 }
 303         }
 304         if (!ast_strlen_zero(cfg->cipher)) {
 305                 if (SSL_CTX_set_cipher_list(cfg->ssl_ctx, cfg->cipher) == 0 ) {
 306                         if (!client) {
 307                                 ast_verb(0, "SSL cipher error <%s>", cfg->cipher);
 308                                 sleep(2);
 309                                 cfg->enabled = 0;
 310                                 return 0;
 311                         }
 312                 }
 313         }
 314         if (!ast_strlen_zero(cfg->cafile) || !ast_strlen_zero(cfg->capath)) {
 315                 if (SSL_CTX_load_verify_locations(cfg->ssl_ctx, S_OR(cfg->cafile, NULL), S_OR(cfg->capath,NULL)) == 0)
 316                         ast_verb(0, "SSL CA file(%s)/path(%s) error\n", cfg->cafile, cfg->capath);
 317         }
 318
 319         ast_verb(0, "SSL certificate ok\n");
 320         return 1;
 321 #endif
 322 }
 323
 324 int ast_ssl_setup(struct ast_tls_config *cfg)
 325 {
 326         return __ssl_setup(cfg, 0);
 327 }
 328
 329 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct ast_tcptls_session_args *desc)
 330 {
 331         int flags;
 332         int x = 1;
 333         struct ast_tcptls_session_instance *tcptls_session = NULL;
 334
 335         /* Do nothing if nothing has changed */
 336         if (!memcmp(&desc->old_address, &desc->remote_address, sizeof(desc->old_address))) {
 337                 ast_debug(1, "Nothing changed in %s\n", desc->name);
 338                 return NULL;
 339         }
 340
 341         desc->old_address = desc->remote_address;
 342
 343         if (desc->accept_fd != -1)
 344                 close(desc->accept_fd);
 345
 346         desc->accept_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 347         if (desc->accept_fd < 0) {
 348                 ast_log(LOG_WARNING, "Unable to allocate socket for %s: %s\n",
 349                         desc->name, strerror(errno));
 350                 return NULL;
 351         }
 352
 353         /* if a local address was specified, bind to it so the connection will
 354            originate from the desired address */
 355         if (desc->local_address.sin_family != 0) {
 356                 setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
 357                 if (bind(desc->accept_fd, (struct sockaddr *) &desc->local_address, sizeof(desc->local_address))) {
 358                         ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
 359                         desc->name,
 360                                 ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
 361                                 strerror(errno));
 362                         goto error;
 363                 }
 364         }
 365
 366         if (connect(desc->accept_fd, (const struct sockaddr *) &desc->remote_address, sizeof(desc->remote_address))) {
 367                 ast_log(LOG_ERROR, "Unable to connect %s to %s:%d: %s\n",
 368                         desc->name,
 369                         ast_inet_ntoa(desc->remote_address.sin_addr), ntohs(desc->remote_address.sin_port),
 370                         strerror(errno));
 371                 goto error;
 372         }
 373
 374         if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor)))
 375                 goto error;
 376
 377         ast_mutex_init(&tcptls_session->lock);
 378
 379         flags = fcntl(desc->accept_fd, F_GETFL);
 380         fcntl(desc->accept_fd, F_SETFL, flags & ~O_NONBLOCK);
 381
 382         tcptls_session->fd = desc->accept_fd;
 383         tcptls_session->parent = desc;
 384         tcptls_session->parent->worker_fn = NULL;
 385         memcpy(&tcptls_session->remote_address, &desc->remote_address, sizeof(tcptls_session->remote_address));
 386
 387         tcptls_session->client = 1;
 388
 389         if (desc->tls_cfg) {
 390                 desc->tls_cfg->enabled = 1;
 391                 __ssl_setup(desc->tls_cfg, 1);
 392         }
 393
 394         ao2_ref(tcptls_session, +1);
 395         if (!handle_tls_connection(tcptls_session))
 396                 goto error;
 397
 398         return tcptls_session;
 399
 400 error:
 401         close(desc->accept_fd);
 402         desc->accept_fd = -1;
 403         if (tcptls_session)
 404                 ao2_ref(tcptls_session, -1);
 405         return NULL;
 406 }
 407
 408 void ast_tcptls_server_start(struct ast_tcptls_session_args *desc)
 409 {
 410         int flags;
 411         int x = 1;
 412
 413         /* Do nothing if nothing has changed */
 414         if (!memcmp(&desc->old_address, &desc->local_address, sizeof(desc->old_address))) {
 415                 ast_debug(1, "Nothing changed in %s\n", desc->name);
 416                 return;
 417         }
 418
 419         desc->old_address = desc->local_address;
 420
 421         /* Shutdown a running server if there is one */
 422         if (desc->master != AST_PTHREADT_NULL) {
 423                 pthread_cancel(desc->master);
 424                 pthread_kill(desc->master, SIGURG);
 425                 pthread_join(desc->master, NULL);
 426         }
 427
 428         if (desc->accept_fd != -1)
 429                 close(desc->accept_fd);
 430
 431         /* If there's no new server, stop here */
 432         if (desc->local_address.sin_family == 0) {
 433                 ast_debug(2, "Server disabled:  %s\n", desc->name);
 434                 return;
 435         }
 436
 437         desc->accept_fd = socket(AF_INET, SOCK_STREAM, 0);
 438         if (desc->accept_fd < 0) {
 439                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n", desc->name, strerror(errno));
 440                 return;
 441         }
 442
 443         setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
 444         if (bind(desc->accept_fd, (struct sockaddr *) &desc->local_address, sizeof(desc->local_address))) {
 445                 ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
 446                         desc->name,
 447                         ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
 448                         strerror(errno));
 449                 goto error;
 450         }
 451         if (listen(desc->accept_fd, 10)) {
 452                 ast_log(LOG_ERROR, "Unable to listen for %s!\n", desc->name);
 453                 goto error;
 454         }
 455         flags = fcntl(desc->accept_fd, F_GETFL);
 456         fcntl(desc->accept_fd, F_SETFL, flags | O_NONBLOCK);
 457         if (ast_pthread_create_background(&desc->master, NULL, desc->accept_fn, desc)) {
 458                 ast_log(LOG_ERROR, "Unable to launch thread for %s on %s:%d: %s\n",
 459                         desc->name,
 460                         ast_inet_ntoa(desc->local_address.sin_addr), ntohs(desc->local_address.sin_port),
 461                         strerror(errno));
 462                 goto error;
 463         }
 464         return;
 465
 466 error:
 467         close(desc->accept_fd);
 468         desc->accept_fd = -1;
 469 }
 470
 471 void ast_tcptls_server_stop(struct ast_tcptls_session_args *desc)
 472 {
 473         if (desc->master != AST_PTHREADT_NULL) {
 474                 pthread_cancel(desc->master);
 475                 pthread_kill(desc->master, SIGURG);
 476                 pthread_join(desc->master, NULL);
 477         }
 478         if (desc->accept_fd != -1)
 479                 close(desc->accept_fd);
 480         desc->accept_fd = -1;
 481         ast_debug(2, "Stopped server :: %s\n", desc->name);
 482 }