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
  46 /*! \brief
  47  * replacement read/write functions for SSL support.
  48  * We use wrappers rather than SSL_read/SSL_write directly so
  49  * we can put in some debugging.
  50  */
  51
  52 #ifdef DO_SSL
  53 static HOOK_T ssl_read(void *cookie, char *buf, LEN_T len)
  54 {
  55         int i = SSL_read(cookie, buf, len-1);
  56 #if 0
  57         if (i >= 0)
  58                 buf[i] = '\0';
  59         ast_verb(0, "ssl read size %d returns %d <%s>\n", (int)len, i, buf);
  60 #endif
  61         return i;
  62 }
  63
  64 static HOOK_T ssl_write(void *cookie, const char *buf, LEN_T len)
  65 {
  66 #if 0
  67         char *s = alloca(len+1);
  68         strncpy(s, buf, len);
  69         s[len] = '\0';
  70         ast_verb(0, "ssl write size %d <%s>\n", (int)len, s);
  71 #endif
  72         return SSL_write(cookie, buf, len);
  73 }
  74
  75 static int ssl_close(void *cookie)
  76 {
  77         close(SSL_get_fd(cookie));
  78         SSL_shutdown(cookie);
  79         SSL_free(cookie);
  80         return 0;
  81 }
  82 #endif  /* DO_SSL */
  83
  84 HOOK_T ast_tcptls_server_read(struct ast_tcptls_session_instance *ser, void *buf, size_t count)
  85 {
  86 #ifdef DO_SSL
  87         if (ser->ssl)
  88                 return ssl_read(ser->ssl, buf, count);
  89 #endif
  90         return read(ser->fd, buf, count);
  91 }
  92
  93 HOOK_T ast_tcptls_server_write(struct ast_tcptls_session_instance *ser, void *buf, size_t count)
  94 {
  95 #ifdef DO_SSL
  96         if (ser->ssl)
  97                 return ssl_write(ser->ssl, buf, count);
  98 #endif
  99         return write(ser->fd, buf, count);
 100 }
 101
 102 void *ast_tcptls_server_root(void *data)
 103 {
 104         struct server_args *desc = data;
 105         int fd;
 106         struct sockaddr_in sin;
 107         socklen_t sinlen;
 108         struct ast_tcptls_session_instance *ser;
 109         pthread_t launched;
 110
 111         for (;;) {
 112                 int i, flags;
 113
 114                 if (desc->periodic_fn)
 115                         desc->periodic_fn(desc);
 116                 i = ast_wait_for_input(desc->accept_fd, desc->poll_timeout);
 117                 if (i <= 0)
 118                         continue;
 119                 sinlen = sizeof(sin);
 120                 fd = accept(desc->accept_fd, (struct sockaddr *)&sin, &sinlen);
 121                 if (fd < 0) {
 122                         if ((errno != EAGAIN) && (errno != EINTR))
 123                                 ast_log(LOG_WARNING, "Accept failed: %s\n", strerror(errno));
 124                         continue;
 125                 }
 126                 ser = ast_calloc(1, sizeof(*ser));
 127                 if (!ser) {
 128                         ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
 129                         close(fd);
 130                         continue;
 131                 }
 132                 flags = fcntl(fd, F_GETFL);
 133                 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
 134                 ser->fd = fd;
 135                 ser->parent = desc;
 136                 memcpy(&ser->requestor, &sin, sizeof(ser->requestor));
 137
 138                 ser->client = 0;
 139
 140                 if (ast_pthread_create_detached_background(&launched, NULL, ast_make_file_from_fd, ser)) {
 141                         ast_log(LOG_WARNING, "Unable to launch helper thread: %s\n", strerror(errno));
 142                         close(ser->fd);
 143                         ast_free(ser);
 144                 }
 145         }
 146         return NULL;
 147 }
 148
 149 static int __ssl_setup(struct ast_tls_config *cfg, int client)
 150 {
 151 #ifndef DO_SSL
 152         cfg->enabled = 0;
 153         return 0;
 154 #else
 155         if (!cfg->enabled)
 156                 return 0;
 157
 158         SSL_load_error_strings();
 159         SSLeay_add_ssl_algorithms();
 160
 161         if (!(cfg->ssl_ctx = SSL_CTX_new( client ? SSLv23_client_method() : SSLv23_server_method() ))) {
 162                 ast_debug(1, "Sorry, SSL_CTX_new call returned null...\n");
 163                 cfg->enabled = 0;
 164                 return 0;
 165         }
 166         if (!ast_strlen_zero(cfg->certfile)) {
 167                 if (SSL_CTX_use_certificate_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
 168                     SSL_CTX_use_PrivateKey_file(cfg->ssl_ctx, cfg->certfile, SSL_FILETYPE_PEM) == 0 ||
 169                     SSL_CTX_check_private_key(cfg->ssl_ctx) == 0 ) {
 170                         if (!client) {
 171                                 /* Clients don't need a certificate, but if its setup we can use it */
 172                                 ast_verb(0, "SSL cert error <%s>", cfg->certfile);
 173                                 sleep(2);
 174                                 cfg->enabled = 0;
 175                                 return 0;
 176                         }
 177                 }
 178         }
 179         if (!ast_strlen_zero(cfg->cipher)) {
 180                 if (SSL_CTX_set_cipher_list(cfg->ssl_ctx, cfg->cipher) == 0 ) {
 181                         if (!client) {
 182                                 ast_verb(0, "SSL cipher error <%s>", cfg->cipher);
 183                                 sleep(2);
 184                                 cfg->enabled = 0;
 185                                 return 0;
 186                         }
 187                 }
 188         }
 189         if (!ast_strlen_zero(cfg->cafile) || !ast_strlen_zero(cfg->capath)) {
 190                 if (SSL_CTX_load_verify_locations(cfg->ssl_ctx, S_OR(cfg->cafile, NULL), S_OR(cfg->capath,NULL)) == 0)
 191                         ast_verb(0, "SSL CA file(%s)/path(%s) error\n", cfg->cafile, cfg->capath);
 192         }
 193
 194         ast_verb(0, "SSL certificate ok\n");
 195         return 1;
 196 #endif
 197 }
 198
 199 int ast_ssl_setup(struct ast_tls_config *cfg)
 200 {
 201         return __ssl_setup(cfg, 0);
 202 }
 203
 204 /*! \brief A generic client routine for a TCP client
 205  *  and starts a thread for handling accept()
 206  */
 207 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct server_args *desc)
 208 {
 209         int flags;
 210         struct ast_tcptls_session_instance *ser = NULL;
 211
 212         /* Do nothing if nothing has changed */
 213         if(!memcmp(&desc->oldsin, &desc->sin, sizeof(desc->oldsin))) {
 214                 ast_debug(1, "Nothing changed in %s\n", desc->name);
 215                 return NULL;
 216         }
 217
 218         desc->oldsin = desc->sin;
 219
 220         if (desc->accept_fd != -1)
 221                 close(desc->accept_fd);
 222
 223         desc->accept_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 224         if (desc->accept_fd < 0) {
 225                 ast_log(LOG_WARNING, "Unable to allocate socket for %s: %s\n",
 226                         desc->name, strerror(errno));
 227                 return NULL;
 228         }
 229
 230         if (connect(desc->accept_fd, (const struct sockaddr *)&desc->sin, sizeof(desc->sin))) {
 231                 ast_log(LOG_ERROR, "Unable to connect %s to %s:%d: %s\n",
 232                         desc->name,
 233                         ast_inet_ntoa(desc->sin.sin_addr), ntohs(desc->sin.sin_port),
 234                         strerror(errno));
 235                 goto error;
 236         }
 237
 238         if (!(ser = ast_calloc(1, sizeof(*ser))))
 239                 goto error;
 240
 241         flags = fcntl(desc->accept_fd, F_GETFL);
 242         fcntl(desc->accept_fd, F_SETFL, flags & ~O_NONBLOCK);
 243
 244         ser->fd = desc->accept_fd;
 245         ser->parent = desc;
 246         ser->parent->worker_fn = NULL;
 247         memcpy(&ser->requestor, &desc->sin, sizeof(ser->requestor));
 248
 249         ser->client = 1;
 250
 251         if (desc->tls_cfg) {
 252                 desc->tls_cfg->enabled = 1;
 253                 __ssl_setup(desc->tls_cfg, 1);
 254         }
 255
 256         if (!ast_make_file_from_fd(ser))
 257                 goto error;
 258
 259         return ser;
 260
 261 error:
 262         close(desc->accept_fd);
 263         desc->accept_fd = -1;
 264         if (ser)
 265                 ast_free(ser);
 266         return NULL;
 267 }
 268
 269 /*! \brief
 270  * This is a generic (re)start routine for a TCP server,
 271  * which does the socket/bind/listen and starts a thread for handling
 272  * accept().
 273  */
 274 void ast_tcptls_server_start(struct server_args *desc)
 275 {
 276         int flags;
 277         int x = 1;
 278
 279         /* Do nothing if nothing has changed */
 280         if (!memcmp(&desc->oldsin, &desc->sin, sizeof(desc->oldsin))) {
 281                 ast_debug(1, "Nothing changed in %s\n", desc->name);
 282                 return;
 283         }
 284
 285         desc->oldsin = desc->sin;
 286
 287         /* Shutdown a running server if there is one */
 288         if (desc->master != AST_PTHREADT_NULL) {
 289                 pthread_cancel(desc->master);
 290                 pthread_kill(desc->master, SIGURG);
 291                 pthread_join(desc->master, NULL);
 292         }
 293
 294         if (desc->accept_fd != -1)
 295                 close(desc->accept_fd);
 296
 297         /* If there's no new server, stop here */
 298         if (desc->sin.sin_family == 0)
 299                 return;
 300
 301         desc->accept_fd = socket(AF_INET, SOCK_STREAM, 0);
 302         if (desc->accept_fd < 0) {
 303                 ast_log(LOG_ERROR, "Unable to allocate socket for %s: %s\n",
 304                         desc->name, strerror(errno));
 305                 return;
 306         }
 307
 308         setsockopt(desc->accept_fd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));
 309         if (bind(desc->accept_fd, (struct sockaddr *)&desc->sin, sizeof(desc->sin))) {
 310                 ast_log(LOG_ERROR, "Unable to bind %s to %s:%d: %s\n",
 311                         desc->name,
 312                         ast_inet_ntoa(desc->sin.sin_addr), ntohs(desc->sin.sin_port),
 313                         strerror(errno));
 314                 goto error;
 315         }
 316         if (listen(desc->accept_fd, 10)) {
 317                 ast_log(LOG_ERROR, "Unable to listen for %s!\n", desc->name);
 318                 goto error;
 319         }
 320         flags = fcntl(desc->accept_fd, F_GETFL);
 321         fcntl(desc->accept_fd, F_SETFL, flags | O_NONBLOCK);
 322         if (ast_pthread_create_background(&desc->master, NULL, desc->accept_fn, desc)) {
 323                 ast_log(LOG_ERROR, "Unable to launch thread for %s on %s:%d: %s\n",
 324                         desc->name,
 325                         ast_inet_ntoa(desc->sin.sin_addr), ntohs(desc->sin.sin_port),
 326                         strerror(errno));
 327                 goto error;
 328         }
 329         return;
 330
 331 error:
 332         close(desc->accept_fd);
 333         desc->accept_fd = -1;
 334 }
 335
 336 /*! \brief Shutdown a running server if there is one */
 337 void ast_tcptls_server_stop(struct server_args *desc)
 338 {
 339         if (desc->master != AST_PTHREADT_NULL) {
 340                 pthread_cancel(desc->master);
 341                 pthread_kill(desc->master, SIGURG);
 342                 pthread_join(desc->master, NULL);
 343         }
 344         if (desc->accept_fd != -1)
 345                 close(desc->accept_fd);
 346         desc->accept_fd = -1;
 347 }
 348
 349 /*! \brief
 350 * creates a FILE * from the fd passed by the accept thread.
 351 * This operation is potentially expensive (certificate verification),
 352 * so we do it in the child thread context.
 353 */
 354 void *ast_make_file_from_fd(void *data)
 355 {
 356         struct ast_tcptls_session_instance *ser = data;
 357 #ifdef DO_SSL
 358         int (*ssl_setup)(SSL *) = (ser->client) ? SSL_connect : SSL_accept;
 359         int ret;
 360         char err[256];
 361 #endif
 362
 363         /*
 364         * open a FILE * as appropriate.
 365         */
 366         if (!ser->parent->tls_cfg)
 367                 ser->f = fdopen(ser->fd, "w+");
 368 #ifdef DO_SSL
 369         else if ( (ser->ssl = SSL_new(ser->parent->tls_cfg->ssl_ctx)) ) {
 370                 SSL_set_fd(ser->ssl, ser->fd);
 371                 if ((ret = ssl_setup(ser->ssl)) <= 0) {
 372                         ast_verb(2, "Problem setting up ssl connection: %s\n", ERR_error_string(ERR_get_error(), err));
 373                 } else {
 374 #if defined(HAVE_FUNOPEN)       /* the BSD interface */
 375                         ser->f = funopen(ser->ssl, ssl_read, ssl_write, NULL, ssl_close);
 376
 377 #elif defined(HAVE_FOPENCOOKIE) /* the glibc/linux interface */
 378                         static const cookie_io_functions_t cookie_funcs = {
 379                                 ssl_read, ssl_write, NULL, ssl_close
 380                         };
 381                         ser->f = fopencookie(ser->ssl, "w+", cookie_funcs);
 382 #else
 383                         /* could add other methods here */
 384                         ast_debug(2, "no ser->f methods attempted!");
 385 #endif
 386                         if ((ser->client && !ast_test_flag(&ser->parent->tls_cfg->flags, AST_SSL_DONT_VERIFY_SERVER))
 387                                 || (!ser->client && ast_test_flag(&ser->parent->tls_cfg->flags, AST_SSL_VERIFY_CLIENT))) {
 388                                 X509 *peer;
 389                                 long res;
 390                                 peer = SSL_get_peer_certificate(ser->ssl);
 391                                 if (!peer)
 392                                         ast_log(LOG_WARNING, "No peer SSL certificate\n");
 393                                 res = SSL_get_verify_result(ser->ssl);
 394                                 if (res != X509_V_OK)
 395                                         ast_log(LOG_ERROR, "Certificate did not verify: %s\n", X509_verify_cert_error_string(res));
 396                                 if (!ast_test_flag(&ser->parent->tls_cfg->flags, AST_SSL_IGNORE_COMMON_NAME)) {
 397                                         ASN1_STRING *str;
 398                                         unsigned char *str2;
 399                                         X509_NAME *name = X509_get_subject_name(peer);
 400                                         int pos = -1;
 401                                         int found = 0;
 402
 403                                         for (;;) {
 404                                                 /* Walk the certificate to check all available "Common Name" */
 405                                                 /* XXX Probably should do a gethostbyname on the hostname and compare that as well */
 406                                                 pos = X509_NAME_get_index_by_NID(name, NID_commonName, pos);
 407                                                 if (pos < 0)
 408                                                         break;
 409                                                 str = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, pos));
 410                                                 ASN1_STRING_to_UTF8(&str2, str);
 411                                                 if (str2) {
 412                                                         if (!strcasecmp(ser->parent->hostname, (char *) str2))
 413                                                                 found = 1;
 414                                                         ast_debug(3, "SSL Common Name compare s1='%s' s2='%s'\n", ser->parent->hostname, str2);
 415                                                         OPENSSL_free(str2);
 416                                                 }
 417                                                 if (found)
 418                                                         break;
 419                                         }
 420                                         if (!found) {
 421                                                 ast_log(LOG_ERROR, "Certificate common name did not match (%s)\n", ser->parent->hostname);
 422                                                 if (peer)
 423                                                         X509_free(peer);
 424                                                 fclose(ser->f);
 425                                                 return NULL;
 426                                         }
 427                                 }
 428                                 if (peer)
 429                                         X509_free(peer);
 430                         }
 431                 }
 432                 if (!ser->f)    /* no success opening descriptor stacking */
 433                         SSL_free(ser->ssl);
 434    }
 435 #endif /* DO_SSL */
 436
 437         if (!ser->f) {
 438                 close(ser->fd);
 439                 ast_log(LOG_WARNING, "FILE * open failed!\n");
 440                 ast_free(ser);
 441                 return NULL;
 442         }
 443
 444         if (ser && ser->parent->worker_fn)
 445                 return ser->parent->worker_fn(ser);
 446         else
 447                 return ser;
 448 }
 449
 450 struct ast_tcptls_session_instance *ast_tcptls_session_instance_destroy(struct ast_tcptls_session_instance *i)
 451 {
 452         ast_free(i);
 453         return NULL;
 454 }