lib/ssl.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2014 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 int openssl_websocket_private_data_index;
  25
  26 #ifndef LWS_NO_SERVER
  27 static int
  28 OpenSSL_verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx)
  29 {
  30         SSL *ssl;
  31         int n;
  32         struct libwebsocket_context *context;
  33
  34         ssl = X509_STORE_CTX_get_ex_data(x509_ctx,
  35                 SSL_get_ex_data_X509_STORE_CTX_idx());
  36
  37         /*
  38          * !!! nasty openssl requires the index to come as a library-scope
  39          * static
  40          */
  41         context = SSL_get_ex_data(ssl, openssl_websocket_private_data_index);
  42
  43         n = context->protocols[0].callback(NULL, NULL,
  44                 LWS_CALLBACK_OPENSSL_PERFORM_CLIENT_CERT_VERIFICATION,
  45                                                    x509_ctx, ssl, preverify_ok);
  46
  47         /* convert return code from 0 = OK to 1 = OK */
  48         return !n;
  49 }
  50
  51 LWS_VISIBLE int
  52 lws_context_init_server_ssl(struct lws_context_creation_info *info,
  53                      struct libwebsocket_context *context)
  54 {
  55         SSL_METHOD *method;
  56         int error;
  57         int n;
  58
  59         if (info->port != CONTEXT_PORT_NO_LISTEN) {
  60
  61                 context->use_ssl = info->ssl_cert_filepath != NULL &&
  62                                          info->ssl_private_key_filepath != NULL;
  63 #ifdef USE_CYASSL
  64                 lwsl_notice(" Compiled with CYASSL support\n");
  65 #else
  66                 lwsl_notice(" Compiled with OpenSSL support\n");
  67 #endif
  68
  69                 if (info->ssl_cipher_list)
  70                         lwsl_notice(" SSL ciphers: '%s'\n", info->ssl_cipher_list);
  71
  72                 if (context->use_ssl)
  73                         lwsl_notice(" Using SSL mode\n");
  74                 else
  75                         lwsl_notice(" Using non-SSL mode\n");
  76         }
  77
  78         /* basic openssl init */
  79
  80         SSL_library_init();
  81
  82         OpenSSL_add_all_algorithms();
  83         SSL_load_error_strings();
  84
  85         openssl_websocket_private_data_index =
  86                 SSL_get_ex_new_index(0, "libwebsockets", NULL, NULL, NULL);
  87
  88         /*
  89          * Firefox insists on SSLv23 not SSLv3
  90          * Konq disables SSLv2 by default now, SSLv23 works
  91          */
  92
  93         method = (SSL_METHOD *)SSLv23_server_method();
  94         if (!method) {
  95                 error = ERR_get_error();
  96                 lwsl_err("problem creating ssl method %lu: %s\n",
  97                         error, ERR_error_string(error,
  98                                               (char *)context->service_buffer));
  99                 return 1;
 100         }
 101         context->ssl_ctx = SSL_CTX_new(method); /* create context */
 102         if (!context->ssl_ctx) {
 103                 error = ERR_get_error();
 104                 lwsl_err("problem creating ssl context %lu: %s\n",
 105                         error, ERR_error_string(error,
 106                                               (char *)context->service_buffer));
 107                 return 1;
 108         }
 109
 110 #ifdef SSL_OP_NO_COMPRESSION
 111         SSL_CTX_set_options(context->ssl_ctx, SSL_OP_NO_COMPRESSION);
 112 #endif
 113         SSL_CTX_set_options(context->ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
 114         if (info->ssl_cipher_list)
 115                 SSL_CTX_set_cipher_list(context->ssl_ctx,
 116                                                 info->ssl_cipher_list);
 117
 118         /* as a server, are we requiring clients to identify themselves? */
 119
 120         if (info->options &
 121                         LWS_SERVER_OPTION_REQUIRE_VALID_OPENSSL_CLIENT_CERT) {
 122
 123                 /* absolutely require the client cert */
 124
 125                 SSL_CTX_set_verify(context->ssl_ctx,
 126                        SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
 127                                                        OpenSSL_verify_callback);
 128
 129                 /*
 130                  * give user code a chance to load certs into the server
 131                  * allowing it to verify incoming client certs
 132                  */
 133
 134                 context->protocols[0].callback(context, NULL,
 135                         LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS,
 136                                                      context->ssl_ctx, NULL, 0);
 137         }
 138
 139         if (info->options & LWS_SERVER_OPTION_ALLOW_NON_SSL_ON_SSL_PORT) {
 140                 /* Normally SSL listener rejects non-ssl, optionally allow */
 141                 context->allow_non_ssl_on_ssl_port = 1;
 142         }
 143
 144         if (context->use_ssl) {
 145
 146                 /* openssl init for server sockets */
 147
 148                 /* set the local certificate from CertFile */
 149                 n = SSL_CTX_use_certificate_chain_file(context->ssl_ctx,
 150                                         info->ssl_cert_filepath);
 151                 if (n != 1) {
 152                         error = ERR_get_error();
 153                         lwsl_err("problem getting cert '%s' %lu: %s\n",
 154                                 info->ssl_cert_filepath,
 155                                 error,
 156                                 ERR_error_string(error,
 157                                               (char *)context->service_buffer));
 158                         return 1;
 159                 }
 160                 /* set the private key from KeyFile */
 161                 if (SSL_CTX_use_PrivateKey_file(context->ssl_ctx,
 162                              info->ssl_private_key_filepath,
 163                                                        SSL_FILETYPE_PEM) != 1) {
 164                         error = ERR_get_error();
 165                         lwsl_err("ssl problem getting key '%s' %lu: %s\n",
 166                                 info->ssl_private_key_filepath,
 167                                         error,
 168                                         ERR_error_string(error,
 169                                               (char *)context->service_buffer));
 170                         return 1;
 171                 }
 172                 /* verify private key */
 173                 if (!SSL_CTX_check_private_key(context->ssl_ctx)) {
 174                         lwsl_err("Private SSL key doesn't match cert\n");
 175                         return 1;
 176                 }
 177
 178                 /*
 179                  * SSL is happy and has a cert it's content with
 180                  * If we're supporting HTTP2, initialize that
 181                  */
 182
 183                 lws_context_init_http2_ssl(context);
 184         }
 185
 186         return 0;
 187 }
 188 #endif
 189
 190 LWS_VISIBLE void
 191 lws_ssl_destroy(struct libwebsocket_context *context)
 192 {
 193         if (context->ssl_ctx)
 194                 SSL_CTX_free(context->ssl_ctx);
 195         if (context->ssl_client_ctx)
 196                 SSL_CTX_free(context->ssl_client_ctx);
 197
 198         ERR_remove_state(0);
 199         ERR_free_strings();
 200         EVP_cleanup();
 201         CRYPTO_cleanup_all_ex_data();
 202 }
 203
 204 LWS_VISIBLE void
 205 libwebsockets_decode_ssl_error(void)
 206 {
 207         char buf[256];
 208         u_long err;
 209
 210         while ((err = ERR_get_error()) != 0) {
 211                 ERR_error_string_n(err, buf, sizeof(buf));
 212                 lwsl_err("*** %lu %s\n", err, buf);
 213         }
 214 }
 215
 216 #ifndef LWS_NO_CLIENT
 217 static int lws_context_init_client_ssl_pem_passwd_cb(char * buf, int size, int rwflag, void * userdata)
 218 {
 219         struct lws_context_creation_info * info = (struct lws_context_creation_info *)userdata;
 220
 221         const int passLen = (int)strlen(info->ssl_private_key_password);
 222         const int minimumLen = passLen < size ? passLen : size;
 223         strncpy(buf, info->ssl_private_key_password, minimumLen);
 224
 225         if (minimumLen < size)
 226         {
 227                 buf[minimumLen] = '\0';
 228        return minimumLen;
 229    }
 230
 231     return minimumLen;
 232 }
 233
 234 int lws_context_init_client_ssl(struct lws_context_creation_info *info,
 235                             struct libwebsocket_context *context)
 236 {
 237         int error;
 238         int n;
 239         SSL_METHOD *method;
 240
 241         if (info->port != CONTEXT_PORT_NO_LISTEN)
 242                 return 0;
 243
 244         method = (SSL_METHOD *)SSLv23_client_method();
 245         if (!method) {
 246                 error = ERR_get_error();
 247                 lwsl_err("problem creating ssl method %lu: %s\n",
 248                         error, ERR_error_string(error,
 249                                       (char *)context->service_buffer));
 250                 return 1;
 251         }
 252         /* create context */
 253         context->ssl_client_ctx = SSL_CTX_new(method);
 254         if (!context->ssl_client_ctx) {
 255                 error = ERR_get_error();
 256                 lwsl_err("problem creating ssl context %lu: %s\n",
 257                         error, ERR_error_string(error,
 258                                       (char *)context->service_buffer));
 259                 return 1;
 260         }
 261
 262 #ifdef SSL_OP_NO_COMPRESSION
 263         SSL_CTX_set_options(context->ssl_client_ctx,
 264                                                  SSL_OP_NO_COMPRESSION);
 265 #endif
 266         SSL_CTX_set_options(context->ssl_client_ctx,
 267                                        SSL_OP_CIPHER_SERVER_PREFERENCE);
 268         if (info->ssl_cipher_list)
 269                 SSL_CTX_set_cipher_list(context->ssl_client_ctx,
 270                                                 info->ssl_cipher_list);
 271
 272 #ifdef LWS_SSL_CLIENT_USE_OS_CA_CERTS
 273         if (!(info->options & LWS_SERVER_OPTION_DISABLE_OS_CA_CERTS))
 274                 /* loads OS default CA certs */
 275                 SSL_CTX_set_default_verify_paths(context->ssl_client_ctx);
 276 #endif
 277
 278         /* openssl init for cert verification (for client sockets) */
 279         if (!info->ssl_ca_filepath) {
 280                 if (!SSL_CTX_load_verify_locations(
 281                         context->ssl_client_ctx, NULL,
 282                                              LWS_OPENSSL_CLIENT_CERTS))
 283                         lwsl_err(
 284                             "Unable to load SSL Client certs from %s "
 285                             "(set by --with-client-cert-dir= "
 286                             "in configure) --  client ssl isn't "
 287                             "going to work", LWS_OPENSSL_CLIENT_CERTS);
 288         } else
 289                 if (!SSL_CTX_load_verify_locations(
 290                         context->ssl_client_ctx, info->ssl_ca_filepath,
 291                                                           NULL))
 292                         lwsl_err(
 293                                 "Unable to load SSL Client certs "
 294                                 "file from %s -- client ssl isn't "
 295                                 "going to work", info->ssl_ca_filepath);
 296
 297         /*
 298          * callback allowing user code to load extra verification certs
 299          * helping the client to verify server identity
 300          */
 301
 302         /* support for client-side certificate authentication */
 303         if (info->ssl_cert_filepath) {
 304                 n = SSL_CTX_use_certificate_chain_file(
 305                         context->ssl_client_ctx,
 306                                         info->ssl_cert_filepath);
 307                 if (n != 1) {
 308                         lwsl_err("problem getting cert '%s' %lu: %s\n",
 309                                 info->ssl_cert_filepath,
 310                                 ERR_get_error(),
 311                                 ERR_error_string(ERR_get_error(),
 312                                 (char *)context->service_buffer));
 313                         return 1;
 314                 }
 315         }
 316         if (info->ssl_private_key_filepath) {
 317                 /* check for provided by user password to private key */
 318                 if (info->ssl_private_key_password) {
 319                 /*
 320                  * password provided, set ssl callback and user data
 321                  * for checking password which will be trigered during
 322                  * SSL_CTX_use_PrivateKey_file function
 323                  */
 324                         SSL_CTX_set_default_passwd_cb_userdata(
 325                                         context->ssl_client_ctx,
 326                                                   (void *)info);
 327                         SSL_CTX_set_default_passwd_cb(context->ssl_client_ctx,
 328                                 lws_context_init_client_ssl_pem_passwd_cb);
 329                 }
 330                 /* set the private key from KeyFile */
 331                 if (SSL_CTX_use_PrivateKey_file(context->ssl_client_ctx,
 332                     info->ssl_private_key_filepath, SSL_FILETYPE_PEM) != 1) {
 333                         lwsl_err("use_PrivateKey_file '%s' %lu: %s\n",
 334                                 info->ssl_private_key_filepath,
 335                                 ERR_get_error(),
 336                                 ERR_error_string(ERR_get_error(),
 337                                       (char *)context->service_buffer));
 338                         return 1;
 339                 }
 340
 341                 /* verify private key */
 342                 if (!SSL_CTX_check_private_key(
 343                                         context->ssl_client_ctx)) {
 344                         lwsl_err("Private SSL key doesn't match cert\n");
 345                         return 1;
 346                 }
 347         }
 348
 349         context->protocols[0].callback(context, NULL,
 350                 LWS_CALLBACK_OPENSSL_LOAD_EXTRA_CLIENT_VERIFY_CERTS,
 351                 context->ssl_client_ctx, NULL, 0);
 352
 353         return 0;
 354 }
 355 #endif
 356
 357 LWS_VISIBLE int
 358 lws_ssl_capable_read(struct libwebsocket_context *context,
 359                      struct libwebsocket *wsi, unsigned char *buf, int len)
 360 {
 361         int n;
 362
 363         if (!wsi->ssl)
 364                 return lws_ssl_capable_read_no_ssl(context, wsi, buf, len);
 365
 366         wsi->buffered_reads_pending = 0;
 367
 368         n = SSL_read(wsi->ssl, buf, len);
 369         if (n >= 0) {
 370                 /*
 371                  * if it was our buffer that limited what we read,
 372                  * check if SSL has additional data pending inside SSL buffers.
 373                  *
 374                  * Because these won't signal at the network layer with POLLIN
 375                  * and if we don't realize, this data will sit there forever
 376                  */
 377                 if (n == len && wsi->ssl && SSL_pending(wsi->ssl)) {
 378                         context->ssl_flag_buffered_reads = 1;
 379                         wsi->buffered_reads_pending = 1;
 380                 }
 381
 382                 return n;
 383         }
 384         n = SSL_get_error(wsi->ssl, n);
 385         if (n ==  SSL_ERROR_WANT_READ || n ==  SSL_ERROR_WANT_WRITE)
 386                 return LWS_SSL_CAPABLE_MORE_SERVICE;
 387
 388         return LWS_SSL_CAPABLE_ERROR;
 389 }
 390
 391 LWS_VISIBLE int
 392 lws_ssl_capable_write(struct libwebsocket *wsi, unsigned char *buf, int len)
 393 {
 394         int n;
 395
 396         if (!wsi->ssl)
 397                 return lws_ssl_capable_write_no_ssl(wsi, buf, len);
 398
 399         n = SSL_write(wsi->ssl, buf, len);
 400         if (n >= 0)
 401                 return n;
 402
 403         n = SSL_get_error(wsi->ssl, n);
 404         if (n == SSL_ERROR_WANT_READ || n == SSL_ERROR_WANT_WRITE) {
 405                 if (n == SSL_ERROR_WANT_WRITE)
 406                         lws_set_blocking_send(wsi);
 407                 return LWS_SSL_CAPABLE_MORE_SERVICE;
 408         }
 409
 410         return LWS_SSL_CAPABLE_ERROR;
 411 }
 412
 413 LWS_VISIBLE int
 414 lws_ssl_close(struct libwebsocket *wsi)
 415 {
 416         int n;
 417
 418         if (!wsi->ssl)
 419                 return 0; /* not handled */
 420
 421         n = SSL_get_fd(wsi->ssl);
 422         SSL_shutdown(wsi->ssl);
 423         compatible_close(n);
 424         SSL_free(wsi->ssl);
 425
 426         return 1; /* handled */
 427 }
 428
 429 LWS_VISIBLE int
 430 lws_server_socket_service_ssl(struct libwebsocket_context *context,
 431                 struct libwebsocket **pwsi, struct libwebsocket *new_wsi,
 432                         int accept_fd, struct libwebsocket_pollfd *pollfd)
 433 {
 434         int n, m;
 435         struct libwebsocket *wsi = *pwsi;
 436 #ifndef USE_CYASSL
 437         BIO *bio;
 438 #endif
 439
 440         if (!LWS_SSL_ENABLED(context))
 441                 return 0;
 442
 443         switch (wsi->mode) {
 444         case LWS_CONNMODE_SERVER_LISTENER:
 445
 446                 if (!new_wsi) {
 447                         lwsl_err("no new_wsi\n");
 448                         return 0;
 449                 }
 450
 451                 new_wsi->ssl = SSL_new(context->ssl_ctx);
 452                 if (new_wsi->ssl == NULL) {
 453                         lwsl_err("SSL_new failed: %s\n",
 454                             ERR_error_string(SSL_get_error(
 455                             new_wsi->ssl, 0), NULL));
 456                             libwebsockets_decode_ssl_error();
 457                         free(new_wsi);
 458                         compatible_close(accept_fd);
 459                         break;
 460                 }
 461
 462                 SSL_set_ex_data(new_wsi->ssl,
 463                         openssl_websocket_private_data_index, context);
 464
 465                 SSL_set_fd(new_wsi->ssl, accept_fd);
 466
 467 #ifdef USE_CYASSL
 468                 CyaSSL_set_using_nonblock(new_wsi->ssl, 1);
 469 #else
 470                 SSL_set_mode(new_wsi->ssl, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
 471                 bio = SSL_get_rbio(new_wsi->ssl);
 472                 if (bio)
 473                         BIO_set_nbio(bio, 1); /* nonblocking */
 474                 else
 475                         lwsl_notice("NULL rbio\n");
 476                 bio = SSL_get_wbio(new_wsi->ssl);
 477                 if (bio)
 478                         BIO_set_nbio(bio, 1); /* nonblocking */
 479                 else
 480                         lwsl_notice("NULL rbio\n");
 481 #endif
 482
 483                 /*
 484                  * we are not accepted yet, but we need to enter ourselves
 485                  * as a live connection.  That way we can retry when more
 486                  * pieces come if we're not sorted yet
 487                  */
 488
 489                 *pwsi = new_wsi;
 490                 wsi = *pwsi;
 491                 wsi->mode = LWS_CONNMODE_SSL_ACK_PENDING;
 492                 insert_wsi_socket_into_fds(context, wsi);
 493
 494                 libwebsocket_set_timeout(wsi, PENDING_TIMEOUT_SSL_ACCEPT,
 495                                                         AWAITING_TIMEOUT);
 496
 497                 lwsl_info("inserted SSL accept into fds, trying SSL_accept\n");
 498
 499                 /* fallthru */
 500
 501         case LWS_CONNMODE_SSL_ACK_PENDING:
 502
 503                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0))
 504                         goto fail;
 505
 506                 lws_libev_io(context, wsi, LWS_EV_STOP | LWS_EV_WRITE);
 507
 508                 lws_latency_pre(context, wsi);
 509
 510                 n = recv(wsi->sock, context->service_buffer,
 511                         sizeof(context->service_buffer), MSG_PEEK);
 512
 513                 /*
 514                  * optionally allow non-SSL connect on SSL listening socket
 515                  * This is disabled by default, if enabled it goes around any
 516                  * SSL-level access control (eg, client-side certs) so leave
 517                  * it disabled unless you know it's not a problem for you
 518                  */
 519
 520                 if (context->allow_non_ssl_on_ssl_port && n >= 1 &&
 521                                         context->service_buffer[0] >= ' ') {
 522                         /*
 523                          * TLS content-type for Handshake is 0x16
 524                          * TLS content-type for ChangeCipherSpec Record is 0x14
 525                          *
 526                          * A non-ssl session will start with the HTTP method in
 527                          * ASCII.  If we see it's not a legit SSL handshake
 528                          * kill the SSL for this connection and try to handle
 529                          * as a HTTP connection upgrade directly.
 530                          */
 531                         wsi->use_ssl = 0;
 532                         SSL_shutdown(wsi->ssl);
 533                         SSL_free(wsi->ssl);
 534                         wsi->ssl = NULL;
 535                         goto accepted;
 536                 }
 537
 538                 /* normal SSL connection processing path */
 539
 540                 n = SSL_accept(wsi->ssl);
 541                 lws_latency(context, wsi,
 542                         "SSL_accept LWS_CONNMODE_SSL_ACK_PENDING\n", n, n == 1);
 543
 544                 if (n == 1)
 545                         goto accepted;
 546
 547                 m = SSL_get_error(wsi->ssl, n);
 548                 lwsl_debug("SSL_accept failed %d / %s\n",
 549                                                   m, ERR_error_string(m, NULL));
 550
 551                 if (m == SSL_ERROR_WANT_READ) {
 552                         if (lws_change_pollfd(wsi, 0, LWS_POLLIN))
 553                                 goto fail;
 554
 555                         lws_libev_io(context, wsi, LWS_EV_START | LWS_EV_READ);
 556
 557                         lwsl_info("SSL_ERROR_WANT_READ\n");
 558                         break;
 559                 }
 560                 if (m == SSL_ERROR_WANT_WRITE) {
 561                         if (lws_change_pollfd(wsi, 0, LWS_POLLOUT))
 562                                 goto fail;
 563
 564                         lws_libev_io(context, wsi, LWS_EV_START | LWS_EV_WRITE);
 565                         break;
 566                 }
 567                 lwsl_debug("SSL_accept failed skt %u: %s\n",
 568                                          pollfd->fd, ERR_error_string(m, NULL));
 569                 libwebsocket_close_and_free_session(context, wsi,
 570                                                      LWS_CLOSE_STATUS_NOSTATUS);
 571                 break;
 572
 573 accepted:
 574                 /* OK, we are accepted... give him some time to negotiate */
 575                 libwebsocket_set_timeout(wsi,
 576                         PENDING_TIMEOUT_ESTABLISH_WITH_SERVER,
 577                                                         AWAITING_TIMEOUT);
 578
 579                 wsi->mode = LWS_CONNMODE_HTTP_SERVING;
 580
 581                 lwsl_debug("accepted new SSL conn\n");
 582                 break;
 583         }
 584
 585         return 0;
 586
 587 fail:
 588         return 1;
 589 }
 590
 591 LWS_VISIBLE void
 592 lws_ssl_context_destroy(struct libwebsocket_context *context)
 593 {
 594         if (context->ssl_ctx)
 595                 SSL_CTX_free(context->ssl_ctx);
 596         if (context->ssl_client_ctx)
 597                 SSL_CTX_free(context->ssl_client_ctx);
 598
 599         ERR_remove_state(0);
 600         ERR_free_strings();
 601         EVP_cleanup();
 602         CRYPTO_cleanup_all_ex_data();
 603 }