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 #ifndef USE_WOLFSSL
  24  #include <openssl/err.h>
  25 #endif
  26
  27 int openssl_websocket_private_data_index;
  28
  29 static int lws_context_init_ssl_pem_passwd_cb(char * buf, int size, int rwflag, void *userdata)
  30 {
  31         struct lws_context_creation_info * info = (struct lws_context_creation_info *)userdata;
  32
  33         strncpy(buf, info->ssl_private_key_password, size);
  34         buf[size - 1] = '\0';
  35
  36         return strlen(buf);
  37 }
  38
  39 static void lws_ssl_bind_passphrase(SSL_CTX *ssl_ctx,
  40                                     struct lws_context_creation_info *info)
  41 {
  42         if (!info->ssl_private_key_password)
  43                 return;
  44         /*
  45          * password provided, set ssl callback and user data
  46          * for checking password which will be trigered during
  47          * SSL_CTX_use_PrivateKey_file function
  48          */
  49         SSL_CTX_set_default_passwd_cb_userdata(ssl_ctx, (void *)info);
  50         SSL_CTX_set_default_passwd_cb(ssl_ctx,
  51                                       lws_context_init_ssl_pem_passwd_cb);
  52 }
  53
  54 #ifndef LWS_NO_SERVER
  55 static int
  56 OpenSSL_verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx)
  57 {
  58         SSL *ssl;
  59         int n;
  60         struct libwebsocket_context *context;
  61
  62         ssl = X509_STORE_CTX_get_ex_data(x509_ctx,
  63                 SSL_get_ex_data_X509_STORE_CTX_idx());
  64
  65         /*
  66          * !!! nasty openssl requires the index to come as a library-scope
  67          * static
  68          */
  69         context = SSL_get_ex_data(ssl, openssl_websocket_private_data_index);
  70
  71         n = context->protocols[0].callback(NULL, NULL,
  72                 LWS_CALLBACK_OPENSSL_PERFORM_CLIENT_CERT_VERIFICATION,
  73                                                    x509_ctx, ssl, preverify_ok);
  74
  75         /* convert return code from 0 = OK to 1 = OK */
  76         return !n;
  77 }
  78
  79 LWS_VISIBLE int
  80 lws_context_init_server_ssl(struct lws_context_creation_info *info,
  81                      struct libwebsocket_context *context)
  82 {
  83         SSL_METHOD *method;
  84         int error;
  85         int n;
  86
  87         if (info->port != CONTEXT_PORT_NO_LISTEN) {
  88
  89                 context->use_ssl = info->ssl_cert_filepath != NULL;
  90
  91 #ifdef USE_WOLFSSL
  92 #ifdef USE_OLD_CYASSL
  93                 lwsl_notice(" Compiled with CyaSSL support\n");
  94 #else
  95                 lwsl_notice(" Compiled with wolfSSL support\n");
  96 #endif
  97 #else
  98                 lwsl_notice(" Compiled with OpenSSL support\n");
  99 #endif
 100
 101                 if (info->ssl_cipher_list)
 102                         lwsl_notice(" SSL ciphers: '%s'\n", info->ssl_cipher_list);
 103
 104                 if (context->use_ssl)
 105                         lwsl_notice(" Using SSL mode\n");
 106                 else
 107                         lwsl_notice(" Using non-SSL mode\n");
 108         }
 109
 110         /* basic openssl init */
 111
 112         SSL_library_init();
 113
 114         OpenSSL_add_all_algorithms();
 115         SSL_load_error_strings();
 116
 117         openssl_websocket_private_data_index =
 118                 SSL_get_ex_new_index(0, "libwebsockets", NULL, NULL, NULL);
 119
 120         /*
 121          * Firefox insists on SSLv23 not SSLv3
 122          * Konq disables SSLv2 by default now, SSLv23 works
 123          *
 124          * SSLv23_server_method() is the openssl method for "allow all TLS
 125          * versions", compared to e.g. TLSv1_2_server_method() which only allows
 126          * tlsv1.2. Unwanted versions must be disabled using SSL_CTX_set_options()
 127          */
 128
 129         method = (SSL_METHOD *)SSLv23_server_method();
 130         if (!method) {
 131                 error = ERR_get_error();
 132                 lwsl_err("problem creating ssl method %lu: %s\n",
 133                         error, ERR_error_string(error,
 134                                               (char *)context->service_buffer));
 135                 return 1;
 136         }
 137         context->ssl_ctx = SSL_CTX_new(method); /* create context */
 138         if (!context->ssl_ctx) {
 139                 error = ERR_get_error();
 140                 lwsl_err("problem creating ssl context %lu: %s\n",
 141                         error, ERR_error_string(error,
 142                                               (char *)context->service_buffer));
 143                 return 1;
 144         }
 145
 146         /* Disable SSLv2 and SSLv3 */
 147         SSL_CTX_set_options(context->ssl_ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
 148 #ifdef SSL_OP_NO_COMPRESSION
 149         SSL_CTX_set_options(context->ssl_ctx, SSL_OP_NO_COMPRESSION);
 150 #endif
 151         SSL_CTX_set_options(context->ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
 152         if (info->ssl_cipher_list)
 153                 SSL_CTX_set_cipher_list(context->ssl_ctx,
 154                                                 info->ssl_cipher_list);
 155
 156         /* as a server, are we requiring clients to identify themselves? */
 157
 158         if (info->options &
 159                         LWS_SERVER_OPTION_REQUIRE_VALID_OPENSSL_CLIENT_CERT) {
 160
 161                 int verify_options = SSL_VERIFY_PEER;
 162
 163                 if (!(info->options & LWS_SERVER_OPTION_PEER_CERT_NOT_REQUIRED))
 164                         verify_options |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
 165
 166                 SSL_CTX_set_session_id_context(context->ssl_ctx,
 167                                 (unsigned char *)context, sizeof(void *));
 168
 169                 /* absolutely require the client cert */
 170
 171                 SSL_CTX_set_verify(context->ssl_ctx,
 172                        verify_options, OpenSSL_verify_callback);
 173
 174                 /*
 175                  * give user code a chance to load certs into the server
 176                  * allowing it to verify incoming client certs
 177                  */
 178
 179                 context->protocols[0].callback(context, NULL,
 180                         LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS,
 181                                                      context->ssl_ctx, NULL, 0);
 182         }
 183
 184         if (info->options & LWS_SERVER_OPTION_ALLOW_NON_SSL_ON_SSL_PORT) {
 185                 /* Normally SSL listener rejects non-ssl, optionally allow */
 186                 context->allow_non_ssl_on_ssl_port = 1;
 187         }
 188
 189         if (context->use_ssl) {
 190
 191                 /* openssl init for server sockets */
 192
 193                 /* set the local certificate from CertFile */
 194                 n = SSL_CTX_use_certificate_chain_file(context->ssl_ctx,
 195                                         info->ssl_cert_filepath);
 196                 if (n != 1) {
 197                         error = ERR_get_error();
 198                         lwsl_err("problem getting cert '%s' %lu: %s\n",
 199                                 info->ssl_cert_filepath,
 200                                 error,
 201                                 ERR_error_string(error,
 202                                               (char *)context->service_buffer));
 203                         return 1;
 204                 }
 205                 lws_ssl_bind_passphrase(context->ssl_ctx, info);
 206
 207                 if (info->ssl_private_key_filepath != NULL) {
 208                         /* set the private key from KeyFile */
 209                         if (SSL_CTX_use_PrivateKey_file(context->ssl_ctx,
 210                                      info->ssl_private_key_filepath,
 211                                                        SSL_FILETYPE_PEM) != 1) {
 212                                 error = ERR_get_error();
 213                                 lwsl_err("ssl problem getting key '%s' %lu: %s\n",
 214                                         info->ssl_private_key_filepath,
 215                                                 error,
 216                                                 ERR_error_string(error,
 217                                                       (char *)context->service_buffer));
 218                                 return 1;
 219                         }
 220                 }
 221                 else {
 222                         if (context->protocols[0].callback(context, NULL,
 223                                 LWS_CALLBACK_OPENSSL_CONTEXT_REQUIRES_PRIVATE_KEY,
 224                                                 context->ssl_ctx, NULL, 0)) {
 225                                 lwsl_err("ssl private key not set\n");
 226                                 return 1;
 227                         }
 228                 }
 229
 230                 /* verify private key */
 231                 if (!SSL_CTX_check_private_key(context->ssl_ctx)) {
 232                         lwsl_err("Private SSL key doesn't match cert\n");
 233                         return 1;
 234                 }
 235
 236                 /*
 237                  * SSL is happy and has a cert it's content with
 238                  * If we're supporting HTTP2, initialize that
 239                  */
 240
 241                 lws_context_init_http2_ssl(context);
 242         }
 243
 244         return 0;
 245 }
 246 #endif
 247
 248 LWS_VISIBLE void
 249 lws_ssl_destroy(struct libwebsocket_context *context)
 250 {
 251         if (context->ssl_ctx)
 252                 SSL_CTX_free(context->ssl_ctx);
 253         if (!context->user_supplied_ssl_ctx && context->ssl_client_ctx)
 254                 SSL_CTX_free(context->ssl_client_ctx);
 255
 256 #if (OPENSSL_VERSION_NUMBER < 0x01000000) || defined(USE_WOLFSSL)
 257         ERR_remove_state(0);
 258 #else
 259         ERR_remove_thread_state(NULL);
 260 #endif
 261         ERR_free_strings();
 262         EVP_cleanup();
 263         CRYPTO_cleanup_all_ex_data();
 264 }
 265
 266 LWS_VISIBLE void
 267 libwebsockets_decode_ssl_error(void)
 268 {
 269         char buf[256];
 270         u_long err;
 271
 272         while ((err = ERR_get_error()) != 0) {
 273                 ERR_error_string_n(err, buf, sizeof(buf));
 274                 lwsl_err("*** %lu %s\n", err, buf);
 275         }
 276 }
 277
 278 #ifndef LWS_NO_CLIENT
 279
 280 int lws_context_init_client_ssl(struct lws_context_creation_info *info,
 281                             struct libwebsocket_context *context)
 282 {
 283         int error;
 284         int n;
 285         SSL_METHOD *method;
 286
 287         if (info->provided_client_ssl_ctx) {
 288                 /* use the provided OpenSSL context if given one */
 289                 context->ssl_client_ctx = info->provided_client_ssl_ctx;
 290                 /* nothing for lib to delete */
 291                 context->user_supplied_ssl_ctx = 1;
 292                 return 0;
 293         }
 294
 295         if (info->port != CONTEXT_PORT_NO_LISTEN)
 296                 return 0;
 297
 298         /* basic openssl init */
 299
 300         SSL_library_init();
 301
 302         OpenSSL_add_all_algorithms();
 303         SSL_load_error_strings();
 304
 305         method = (SSL_METHOD *)SSLv23_client_method();
 306         if (!method) {
 307                 error = ERR_get_error();
 308                 lwsl_err("problem creating ssl method %lu: %s\n",
 309                         error, ERR_error_string(error,
 310                                       (char *)context->service_buffer));
 311                 return 1;
 312         }
 313         /* create context */
 314         context->ssl_client_ctx = SSL_CTX_new(method);
 315         if (!context->ssl_client_ctx) {
 316                 error = ERR_get_error();
 317                 lwsl_err("problem creating ssl context %lu: %s\n",
 318                         error, ERR_error_string(error,
 319                                       (char *)context->service_buffer));
 320                 return 1;
 321         }
 322
 323 #ifdef SSL_OP_NO_COMPRESSION
 324         SSL_CTX_set_options(context->ssl_client_ctx,
 325                                                  SSL_OP_NO_COMPRESSION);
 326 #endif
 327         SSL_CTX_set_options(context->ssl_client_ctx,
 328                                        SSL_OP_CIPHER_SERVER_PREFERENCE);
 329         if (info->ssl_cipher_list)
 330                 SSL_CTX_set_cipher_list(context->ssl_client_ctx,
 331                                                 info->ssl_cipher_list);
 332
 333 #ifdef LWS_SSL_CLIENT_USE_OS_CA_CERTS
 334         if (!(info->options & LWS_SERVER_OPTION_DISABLE_OS_CA_CERTS))
 335                 /* loads OS default CA certs */
 336                 SSL_CTX_set_default_verify_paths(context->ssl_client_ctx);
 337 #endif
 338
 339         /* openssl init for cert verification (for client sockets) */
 340         if (!info->ssl_ca_filepath) {
 341                 if (!SSL_CTX_load_verify_locations(
 342                         context->ssl_client_ctx, NULL,
 343                                              LWS_OPENSSL_CLIENT_CERTS))
 344                         lwsl_err(
 345                             "Unable to load SSL Client certs from %s "
 346                             "(set by --with-client-cert-dir= "
 347                             "in configure) --  client ssl isn't "
 348                             "going to work", LWS_OPENSSL_CLIENT_CERTS);
 349         } else
 350                 if (!SSL_CTX_load_verify_locations(
 351                         context->ssl_client_ctx, info->ssl_ca_filepath,
 352                                                           NULL))
 353                         lwsl_err(
 354                                 "Unable to load SSL Client certs "
 355                                 "file from %s -- client ssl isn't "
 356                                 "going to work", info->ssl_ca_filepath);
 357                 else
 358                         lwsl_info("loaded ssl_ca_filepath\n");
 359
 360         /*
 361          * callback allowing user code to load extra verification certs
 362          * helping the client to verify server identity
 363          */
 364
 365         /* support for client-side certificate authentication */
 366         if (info->ssl_cert_filepath) {
 367                 n = SSL_CTX_use_certificate_chain_file(
 368                         context->ssl_client_ctx,
 369                                         info->ssl_cert_filepath);
 370                 if (n != 1) {
 371                         lwsl_err("problem getting cert '%s' %lu: %s\n",
 372                                 info->ssl_cert_filepath,
 373                                 ERR_get_error(),
 374                                 ERR_error_string(ERR_get_error(),
 375                                 (char *)context->service_buffer));
 376                         return 1;
 377                 }
 378         }
 379         if (info->ssl_private_key_filepath) {
 380                 lws_ssl_bind_passphrase(context->ssl_client_ctx, info);
 381                 /* set the private key from KeyFile */
 382                 if (SSL_CTX_use_PrivateKey_file(context->ssl_client_ctx,
 383                     info->ssl_private_key_filepath, SSL_FILETYPE_PEM) != 1) {
 384                         lwsl_err("use_PrivateKey_file '%s' %lu: %s\n",
 385                                 info->ssl_private_key_filepath,
 386                                 ERR_get_error(),
 387                                 ERR_error_string(ERR_get_error(),
 388                                       (char *)context->service_buffer));
 389                         return 1;
 390                 }
 391
 392                 /* verify private key */
 393                 if (!SSL_CTX_check_private_key(
 394                                         context->ssl_client_ctx)) {
 395                         lwsl_err("Private SSL key doesn't match cert\n");
 396                         return 1;
 397                 }
 398         }
 399
 400         context->protocols[0].callback(context, NULL,
 401                 LWS_CALLBACK_OPENSSL_LOAD_EXTRA_CLIENT_VERIFY_CERTS,
 402                 context->ssl_client_ctx, NULL, 0);
 403
 404         return 0;
 405 }
 406 #endif
 407
 408 LWS_VISIBLE void
 409 lws_ssl_remove_wsi_from_buffered_list(struct libwebsocket_context *context,
 410                      struct libwebsocket *wsi)
 411 {
 412         if (!wsi->pending_read_list_prev &&
 413             !wsi->pending_read_list_next &&
 414             context->pending_read_list != wsi)
 415                 /* we are not on the list */
 416                 return;
 417
 418         /* point previous guy's next to our next */
 419         if (!wsi->pending_read_list_prev)
 420                 context->pending_read_list = wsi->pending_read_list_next;
 421         else
 422                 wsi->pending_read_list_prev->pending_read_list_next =
 423                         wsi->pending_read_list_next;
 424
 425         /* point next guy's previous to our previous */
 426         if (wsi->pending_read_list_next)
 427                 wsi->pending_read_list_next->pending_read_list_prev =
 428                         wsi->pending_read_list_prev;
 429
 430         wsi->pending_read_list_prev = NULL;
 431         wsi->pending_read_list_next = NULL;
 432 }
 433
 434 LWS_VISIBLE int
 435 lws_ssl_capable_read(struct libwebsocket_context *context,
 436                      struct libwebsocket *wsi, unsigned char *buf, int len)
 437 {
 438         int n;
 439
 440         if (!wsi->ssl)
 441                 return lws_ssl_capable_read_no_ssl(context, wsi, buf, len);
 442
 443         n = SSL_read(wsi->ssl, buf, len);
 444         if (n >= 0) {
 445                 /*
 446                  * if it was our buffer that limited what we read,
 447                  * check if SSL has additional data pending inside SSL buffers.
 448                  *
 449                  * Because these won't signal at the network layer with POLLIN
 450                  * and if we don't realize, this data will sit there forever
 451                  */
 452                 if (n == len && wsi->ssl && SSL_pending(wsi->ssl)) {
 453                         if (!wsi->pending_read_list_next && !wsi->pending_read_list_prev) {
 454                                 if (context->pending_read_list != wsi) {
 455                                         /* add us to the linked list of guys with pending ssl */
 456                                         if (context->pending_read_list)
 457                                                 context->pending_read_list->pending_read_list_prev = wsi;
 458                                         wsi->pending_read_list_next = context->pending_read_list;
 459                                         wsi->pending_read_list_prev = NULL;
 460                                         context->pending_read_list = wsi;
 461                                 }
 462                         }
 463                 } else
 464                         lws_ssl_remove_wsi_from_buffered_list(context, wsi);
 465
 466                 return n;
 467         }
 468         n = SSL_get_error(wsi->ssl, n);
 469         if (n ==  SSL_ERROR_WANT_READ || n ==  SSL_ERROR_WANT_WRITE)
 470                 return LWS_SSL_CAPABLE_MORE_SERVICE;
 471
 472         return LWS_SSL_CAPABLE_ERROR;
 473 }
 474
 475 LWS_VISIBLE int
 476 lws_ssl_pending(struct libwebsocket *wsi)
 477 {
 478         if (!wsi->ssl)
 479                 return 0;
 480
 481         return SSL_pending(wsi->ssl);
 482 }
 483
 484 LWS_VISIBLE int
 485 lws_ssl_capable_write(struct libwebsocket *wsi, unsigned char *buf, int len)
 486 {
 487         int n;
 488
 489         if (!wsi->ssl)
 490                 return lws_ssl_capable_write_no_ssl(wsi, buf, len);
 491
 492         n = SSL_write(wsi->ssl, buf, len);
 493         if (n >= 0)
 494                 return n;
 495
 496         n = SSL_get_error(wsi->ssl, n);
 497         if (n == SSL_ERROR_WANT_READ || n == SSL_ERROR_WANT_WRITE) {
 498                 if (n == SSL_ERROR_WANT_WRITE)
 499                         lws_set_blocking_send(wsi);
 500                 return LWS_SSL_CAPABLE_MORE_SERVICE;
 501         }
 502
 503         return LWS_SSL_CAPABLE_ERROR;
 504 }
 505
 506 LWS_VISIBLE int
 507 lws_ssl_close(struct libwebsocket *wsi)
 508 {
 509         int n;
 510
 511         if (!wsi->ssl)
 512                 return 0; /* not handled */
 513
 514         n = SSL_get_fd(wsi->ssl);
 515         SSL_shutdown(wsi->ssl);
 516         compatible_close(n);
 517         SSL_free(wsi->ssl);
 518
 519         return 1; /* handled */
 520 }
 521
 522 LWS_VISIBLE int
 523 lws_server_socket_service_ssl(struct libwebsocket_context *context,
 524                 struct libwebsocket **pwsi, struct libwebsocket *new_wsi,
 525                         int accept_fd, struct libwebsocket_pollfd *pollfd)
 526 {
 527         int n, m;
 528         struct libwebsocket *wsi = *pwsi;
 529 #ifndef USE_WOLFSSL
 530         BIO *bio;
 531 #endif
 532
 533         if (!LWS_SSL_ENABLED(context))
 534                 return 0;
 535
 536         switch (wsi->mode) {
 537         case LWS_CONNMODE_SERVER_LISTENER:
 538
 539                 if (!new_wsi) {
 540                         lwsl_err("no new_wsi\n");
 541                         return 0;
 542                 }
 543
 544                 new_wsi->ssl = SSL_new(context->ssl_ctx);
 545                 if (new_wsi->ssl == NULL) {
 546                         lwsl_err("SSL_new failed: %s\n",
 547                                         ERR_error_string(SSL_get_error(new_wsi->ssl, 0), NULL));
 548                         libwebsockets_decode_ssl_error();
 549
 550                         // TODO: Shouldn't the caller handle this?
 551                         compatible_close(accept_fd);
 552                         goto fail;
 553                 }
 554
 555                 SSL_set_ex_data(new_wsi->ssl,
 556                         openssl_websocket_private_data_index, context);
 557
 558                 SSL_set_fd(new_wsi->ssl, accept_fd);
 559
 560 #ifdef USE_WOLFSSL
 561 #ifdef USE_OLD_CYASSL
 562                 CyaSSL_set_using_nonblock(new_wsi->ssl, 1);
 563 #else
 564                 wolfSSL_set_using_nonblock(new_wsi->ssl, 1);
 565 #endif
 566 #else
 567                 SSL_set_mode(new_wsi->ssl, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
 568                 bio = SSL_get_rbio(new_wsi->ssl);
 569                 if (bio)
 570                         BIO_set_nbio(bio, 1); /* nonblocking */
 571                 else
 572                         lwsl_notice("NULL rbio\n");
 573                 bio = SSL_get_wbio(new_wsi->ssl);
 574                 if (bio)
 575                         BIO_set_nbio(bio, 1); /* nonblocking */
 576                 else
 577                         lwsl_notice("NULL rbio\n");
 578 #endif
 579
 580                 /*
 581                  * we are not accepted yet, but we need to enter ourselves
 582                  * as a live connection.  That way we can retry when more
 583                  * pieces come if we're not sorted yet
 584                  */
 585
 586                 *pwsi = new_wsi;
 587                 wsi = *pwsi;
 588                 wsi->mode = LWS_CONNMODE_SSL_ACK_PENDING;
 589                 if (insert_wsi_socket_into_fds(context, wsi))
 590                         goto fail;
 591
 592                 libwebsocket_set_timeout(wsi, PENDING_TIMEOUT_SSL_ACCEPT,
 593                                                         AWAITING_TIMEOUT);
 594
 595                 lwsl_info("inserted SSL accept into fds, trying SSL_accept\n");
 596
 597                 /* fallthru */
 598
 599         case LWS_CONNMODE_SSL_ACK_PENDING:
 600
 601                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0))
 602                         goto fail;
 603
 604                 lws_libev_io(context, wsi, LWS_EV_STOP | LWS_EV_WRITE);
 605
 606                 lws_latency_pre(context, wsi);
 607
 608                 n = recv(wsi->sock, (char *)context->service_buffer,
 609                         sizeof(context->service_buffer), MSG_PEEK);
 610
 611                 /*
 612                  * optionally allow non-SSL connect on SSL listening socket
 613                  * This is disabled by default, if enabled it goes around any
 614                  * SSL-level access control (eg, client-side certs) so leave
 615                  * it disabled unless you know it's not a problem for you
 616                  */
 617
 618                 if (context->allow_non_ssl_on_ssl_port) {
 619                         if (n >= 1 && context->service_buffer[0] >= ' ') {
 620                                 /*
 621                                 * TLS content-type for Handshake is 0x16, and
 622                                 * for ChangeCipherSpec Record, it's 0x14
 623                                 *
 624                                 * A non-ssl session will start with the HTTP
 625                                 * method in ASCII.  If we see it's not a legit
 626                                 * SSL handshake kill the SSL for this
 627                                 * connection and try to handle as a HTTP
 628                                 * connection upgrade directly.
 629                                 */
 630                                 wsi->use_ssl = 0;
 631                                 SSL_shutdown(wsi->ssl);
 632                                 SSL_free(wsi->ssl);
 633                                 wsi->ssl = NULL;
 634                                 goto accepted;
 635                         }
 636                         if (n == 0 || LWS_ERRNO == LWS_EAGAIN ||
 637                             LWS_ERRNO == LWS_EWOULDBLOCK) {
 638                                 /*
 639                                  * well, we get no way to know ssl or not
 640                                  * so go around again waiting for something
 641                                  * to come and give us a hint, or timeout the
 642                                  * connection.
 643                                  */
 644                                 m = SSL_ERROR_WANT_READ;
 645                                 goto go_again;
 646                         }
 647                 }
 648
 649                 /* normal SSL connection processing path */
 650
 651                 n = SSL_accept(wsi->ssl);
 652                 lws_latency(context, wsi,
 653                         "SSL_accept LWS_CONNMODE_SSL_ACK_PENDING\n", n, n == 1);
 654
 655                 if (n == 1)
 656                         goto accepted;
 657
 658                 m = SSL_get_error(wsi->ssl, n);
 659                 lwsl_debug("SSL_accept failed %d / %s\n",
 660                                                   m, ERR_error_string(m, NULL));
 661 go_again:
 662                 if (m == SSL_ERROR_WANT_READ) {
 663                         if (lws_change_pollfd(wsi, 0, LWS_POLLIN))
 664                                 goto fail;
 665
 666                         lws_libev_io(context, wsi, LWS_EV_START | LWS_EV_READ);
 667
 668                         lwsl_info("SSL_ERROR_WANT_READ\n");
 669                         break;
 670                 }
 671                 if (m == SSL_ERROR_WANT_WRITE) {
 672                         if (lws_change_pollfd(wsi, 0, LWS_POLLOUT))
 673                                 goto fail;
 674
 675                         lws_libev_io(context, wsi, LWS_EV_START | LWS_EV_WRITE);
 676                         break;
 677                 }
 678                 lwsl_debug("SSL_accept failed skt %u: %s\n",
 679                                          pollfd->fd, ERR_error_string(m, NULL));
 680                 goto fail;
 681
 682 accepted:
 683                 /* OK, we are accepted... give him some time to negotiate */
 684                 libwebsocket_set_timeout(wsi,
 685                         PENDING_TIMEOUT_ESTABLISH_WITH_SERVER,
 686                                                         AWAITING_TIMEOUT);
 687
 688                 wsi->mode = LWS_CONNMODE_HTTP_SERVING;
 689
 690                 lws_http2_configure_if_upgraded(wsi);
 691
 692                 lwsl_debug("accepted new SSL conn\n");
 693                 break;
 694         }
 695
 696         return 0;
 697
 698 fail:
 699         return 1;
 700 }
 701
 702 LWS_VISIBLE void
 703 lws_ssl_context_destroy(struct libwebsocket_context *context)
 704 {
 705         if (context->ssl_ctx)
 706                 SSL_CTX_free(context->ssl_ctx);
 707         if (!context->user_supplied_ssl_ctx && context->ssl_client_ctx)
 708                 SSL_CTX_free(context->ssl_client_ctx);
 709
 710 #if (OPENSSL_VERSION_NUMBER < 0x01000000) || defined(USE_WOLFSSL)
 711         ERR_remove_state(0);
 712 #else
 713         ERR_remove_thread_state(NULL);
 714 #endif
 715         ERR_free_strings();
 716         EVP_cleanup();
 717         CRYPTO_cleanup_all_ex_data();
 718 }