test/handshake_helper.c

   1 /*
   2  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <string.h>
  11
  12 #include <openssl/bio.h>
  13 #include <openssl/x509_vfy.h>
  14 #include <openssl/ssl.h>
  15
  16 #include "handshake_helper.h"
  17
  18 HANDSHAKE_RESULT *HANDSHAKE_RESULT_new()
  19 {
  20     HANDSHAKE_RESULT *ret;
  21     ret = OPENSSL_zalloc(sizeof(*ret));
  22     OPENSSL_assert(ret != NULL);
  23     return ret;
  24 }
  25
  26 void HANDSHAKE_RESULT_free(HANDSHAKE_RESULT *result)
  27 {
  28     OPENSSL_free(result->client_npn_negotiated);
  29     OPENSSL_free(result->server_npn_negotiated);
  30     OPENSSL_free(result->client_alpn_negotiated);
  31     OPENSSL_free(result->server_alpn_negotiated);
  32     OPENSSL_free(result);
  33 }
  34
  35 /*
  36  * Since there appears to be no way to extract the sent/received alert
  37  * from the SSL object directly, we use the info callback and stash
  38  * the result in ex_data.
  39  */
  40 typedef struct handshake_ex_data {
  41     int alert_sent;
  42     int alert_received;
  43     int session_ticket_do_not_call;
  44     ssl_servername_t servername;
  45 } HANDSHAKE_EX_DATA;
  46
  47 typedef struct ctx_data {
  48     unsigned char *npn_protocols;
  49     size_t npn_protocols_len;
  50     unsigned char *alpn_protocols;
  51     size_t alpn_protocols_len;
  52 } CTX_DATA;
  53
  54 /* |ctx_data| itself is stack-allocated. */
  55 static void ctx_data_free_data(CTX_DATA *ctx_data)
  56 {
  57     OPENSSL_free(ctx_data->npn_protocols);
  58     ctx_data->npn_protocols = NULL;
  59     OPENSSL_free(ctx_data->alpn_protocols);
  60     ctx_data->alpn_protocols = NULL;
  61 }
  62
  63 static int ex_data_idx;
  64
  65 static void info_cb(const SSL *s, int where, int ret)
  66 {
  67     if (where & SSL_CB_ALERT) {
  68         HANDSHAKE_EX_DATA *ex_data =
  69             (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
  70         if (where & SSL_CB_WRITE) {
  71             ex_data->alert_sent = ret;
  72         } else {
  73             ex_data->alert_received = ret;
  74         }
  75     }
  76 }
  77
  78 /* Select the appropriate server CTX.
  79  * Returns SSL_TLSEXT_ERR_OK if a match was found.
  80  * If |ignore| is 1, returns SSL_TLSEXT_ERR_NOACK on mismatch.
  81  * Otherwise, returns SSL_TLSEXT_ERR_ALERT_FATAL on mismatch.
  82  * An empty SNI extension also returns SSL_TSLEXT_ERR_NOACK.
  83  */
  84 static int select_server_ctx(SSL *s, void *arg, int ignore)
  85 {
  86     const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
  87     HANDSHAKE_EX_DATA *ex_data =
  88         (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
  89
  90     if (servername == NULL) {
  91         ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
  92         return SSL_TLSEXT_ERR_NOACK;
  93     }
  94
  95     if (strcmp(servername, "server2") == 0) {
  96         SSL_CTX *new_ctx = (SSL_CTX*)arg;
  97         SSL_set_SSL_CTX(s, new_ctx);
  98         /*
  99          * Copy over all the SSL_CTX options - reasonable behavior
 100          * allows testing of cases where the options between two
 101          * contexts differ/conflict
 102          */
 103         SSL_clear_options(s, 0xFFFFFFFFL);
 104         SSL_set_options(s, SSL_CTX_get_options(new_ctx));
 105
 106         ex_data->servername = SSL_TEST_SERVERNAME_SERVER2;
 107         return SSL_TLSEXT_ERR_OK;
 108     } else if (strcmp(servername, "server1") == 0) {
 109         ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
 110         return SSL_TLSEXT_ERR_OK;
 111     } else if (ignore) {
 112         ex_data->servername = SSL_TEST_SERVERNAME_SERVER1;
 113         return SSL_TLSEXT_ERR_NOACK;
 114     } else {
 115         /* Don't set an explicit alert, to test library defaults. */
 116         return SSL_TLSEXT_ERR_ALERT_FATAL;
 117     }
 118 }
 119
 120 /*
 121  * (RFC 6066):
 122  *  If the server understood the ClientHello extension but
 123  *  does not recognize the server name, the server SHOULD take one of two
 124  *  actions: either abort the handshake by sending a fatal-level
 125  *  unrecognized_name(112) alert or continue the handshake.
 126  *
 127  * This behaviour is up to the application to configure; we test both
 128  * configurations to ensure the state machine propagates the result
 129  * correctly.
 130  */
 131 static int servername_ignore_cb(SSL *s, int *ad, void *arg)
 132 {
 133     return select_server_ctx(s, arg, 1);
 134 }
 135
 136 static int servername_reject_cb(SSL *s, int *ad, void *arg)
 137 {
 138     return select_server_ctx(s, arg, 0);
 139 }
 140
 141 static int verify_reject_cb(X509_STORE_CTX *ctx, void *arg) {
 142     X509_STORE_CTX_set_error(ctx, X509_V_ERR_APPLICATION_VERIFICATION);
 143     return 0;
 144 }
 145
 146 static int verify_accept_cb(X509_STORE_CTX *ctx, void *arg) {
 147     return 1;
 148 }
 149
 150 static int broken_session_ticket_cb(SSL *s, unsigned char *key_name, unsigned char *iv,
 151                                     EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int enc)
 152 {
 153     return 0;
 154 }
 155
 156 static int do_not_call_session_ticket_cb(SSL *s, unsigned char *key_name,
 157                                          unsigned char *iv,
 158                                          EVP_CIPHER_CTX *ctx,
 159                                          HMAC_CTX *hctx, int enc)
 160 {
 161     HANDSHAKE_EX_DATA *ex_data =
 162         (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx));
 163     ex_data->session_ticket_do_not_call = 1;
 164     return 0;
 165 }
 166
 167 #ifndef OPENSSL_NO_NEXTPROTONEG
 168 /* Parse the comma-separated list into TLS format. */
 169 static void parse_protos(const char *protos, unsigned char **out, size_t *outlen)
 170 {
 171     size_t len, i, prefix;
 172
 173     len = strlen(protos);
 174
 175     /* Should never have reuse. */
 176     OPENSSL_assert(*out == NULL);
 177
 178     /* Test values are small, so we omit length limit checks. */
 179     *out = OPENSSL_malloc(len + 1);
 180     OPENSSL_assert(*out != NULL);
 181     *outlen = len + 1;
 182
 183     /*
 184      * foo => '3', 'f', 'o', 'o'
 185      * foo,bar => '3', 'f', 'o', 'o', '3', 'b', 'a', 'r'
 186      */
 187     memcpy(*out + 1, protos, len);
 188
 189     prefix = 0;
 190     i = prefix + 1;
 191     while (i <= len) {
 192         if ((*out)[i] == ',') {
 193             OPENSSL_assert(i - 1 - prefix > 0);
 194             (*out)[prefix] = i - 1 - prefix;
 195             prefix = i;
 196         }
 197         i++;
 198     }
 199     OPENSSL_assert(len - prefix > 0);
 200     (*out)[prefix] = len - prefix;
 201 }
 202
 203 /*
 204  * The client SHOULD select the first protocol advertised by the server that it
 205  * also supports.  In the event that the client doesn't support any of server's
 206  * protocols, or the server doesn't advertise any, it SHOULD select the first
 207  * protocol that it supports.
 208  */
 209 static int client_npn_cb(SSL *s, unsigned char **out, unsigned char *outlen,
 210                          const unsigned char *in, unsigned int inlen,
 211                          void *arg)
 212 {
 213     CTX_DATA *ctx_data = (CTX_DATA*)(arg);
 214     int ret;
 215
 216     ret = SSL_select_next_proto(out, outlen, in, inlen,
 217                                 ctx_data->npn_protocols,
 218                                 ctx_data->npn_protocols_len);
 219     /* Accept both OPENSSL_NPN_NEGOTIATED and OPENSSL_NPN_NO_OVERLAP. */
 220     OPENSSL_assert(ret == OPENSSL_NPN_NEGOTIATED
 221                    || ret == OPENSSL_NPN_NO_OVERLAP);
 222     return SSL_TLSEXT_ERR_OK;
 223 }
 224
 225 static int server_npn_cb(SSL *s, const unsigned char **data,
 226                          unsigned int *len, void *arg)
 227 {
 228     CTX_DATA *ctx_data = (CTX_DATA*)(arg);
 229     *data = ctx_data->npn_protocols;
 230     *len = ctx_data->npn_protocols_len;
 231     return SSL_TLSEXT_ERR_OK;
 232 }
 233
 234 /*
 235  * The server SHOULD select the most highly preferred protocol that it supports
 236  * and that is also advertised by the client.  In the event that the server
 237  * supports no protocols that the client advertises, then the server SHALL
 238  * respond with a fatal "no_application_protocol" alert.
 239  */
 240 static int server_alpn_cb(SSL *s, const unsigned char **out,
 241                           unsigned char *outlen, const unsigned char *in,
 242                           unsigned int inlen, void *arg)
 243 {
 244     CTX_DATA *ctx_data = (CTX_DATA*)(arg);
 245     int ret;
 246
 247     /* SSL_select_next_proto isn't const-correct... */
 248     unsigned char *tmp_out;
 249
 250     /*
 251      * The result points either to |in| or to |ctx_data->alpn_protocols|.
 252      * The callback is allowed to point to |in| or to a long-lived buffer,
 253      * so we can return directly without storing a copy.
 254      */
 255     ret = SSL_select_next_proto(&tmp_out, outlen,
 256                                 ctx_data->alpn_protocols,
 257                                 ctx_data->alpn_protocols_len, in, inlen);
 258
 259     *out = tmp_out;
 260     /* Unlike NPN, we don't tolerate a mismatch. */
 261     return ret == OPENSSL_NPN_NEGOTIATED ? SSL_TLSEXT_ERR_OK
 262         : SSL_TLSEXT_ERR_NOACK;
 263 }
 264 #endif
 265
 266 /*
 267  * Configure callbacks and other properties that can't be set directly
 268  * in the server/client CONF.
 269  */
 270 static void configure_handshake_ctx(SSL_CTX *server_ctx, SSL_CTX *server2_ctx,
 271                                     SSL_CTX *client_ctx,
 272                                     const SSL_TEST_EXTRA_CONF *extra,
 273                                     CTX_DATA *server_ctx_data,
 274                                     CTX_DATA *server2_ctx_data,
 275                                     CTX_DATA *client_ctx_data)
 276 {
 277     unsigned char *ticket_keys;
 278     size_t ticket_key_len;
 279
 280     switch (extra->client.verify_callback) {
 281     case SSL_TEST_VERIFY_ACCEPT_ALL:
 282         SSL_CTX_set_cert_verify_callback(client_ctx, &verify_accept_cb,
 283                                          NULL);
 284         break;
 285     case SSL_TEST_VERIFY_REJECT_ALL:
 286         SSL_CTX_set_cert_verify_callback(client_ctx, &verify_reject_cb,
 287                                          NULL);
 288         break;
 289     default:
 290         break;
 291     }
 292
 293     /* link the two contexts for SNI purposes */
 294     switch (extra->server.servername_callback) {
 295     case SSL_TEST_SERVERNAME_IGNORE_MISMATCH:
 296         SSL_CTX_set_tlsext_servername_callback(server_ctx, servername_ignore_cb);
 297         SSL_CTX_set_tlsext_servername_arg(server_ctx, server2_ctx);
 298         break;
 299     case SSL_TEST_SERVERNAME_REJECT_MISMATCH:
 300         SSL_CTX_set_tlsext_servername_callback(server_ctx, servername_reject_cb);
 301         SSL_CTX_set_tlsext_servername_arg(server_ctx, server2_ctx);
 302         break;
 303     default:
 304         break;
 305     }
 306
 307     /*
 308      * The initial_ctx/session_ctx always handles the encrypt/decrypt of the
 309      * session ticket. This ticket_key callback is assigned to the second
 310      * session (assigned via SNI), and should never be invoked
 311      */
 312     if (server2_ctx != NULL)
 313         SSL_CTX_set_tlsext_ticket_key_cb(server2_ctx,
 314                                          do_not_call_session_ticket_cb);
 315
 316     if (extra->server.broken_session_ticket) {
 317         SSL_CTX_set_tlsext_ticket_key_cb(server_ctx, broken_session_ticket_cb);
 318     }
 319 #ifndef OPENSSL_NO_NEXTPROTONEG
 320     if (extra->server.npn_protocols != NULL) {
 321         parse_protos(extra->server.npn_protocols,
 322                      &server_ctx_data->npn_protocols,
 323                      &server_ctx_data->npn_protocols_len);
 324         SSL_CTX_set_next_protos_advertised_cb(server_ctx, server_npn_cb,
 325                                               server_ctx_data);
 326     }
 327     if (extra->server2.npn_protocols != NULL) {
 328         parse_protos(extra->server2.npn_protocols,
 329                      &server2_ctx_data->npn_protocols,
 330                      &server2_ctx_data->npn_protocols_len);
 331         OPENSSL_assert(server2_ctx != NULL);
 332         SSL_CTX_set_next_protos_advertised_cb(server2_ctx, server_npn_cb,
 333                                               server2_ctx_data);
 334     }
 335     if (extra->client.npn_protocols != NULL) {
 336         parse_protos(extra->client.npn_protocols,
 337                      &client_ctx_data->npn_protocols,
 338                      &client_ctx_data->npn_protocols_len);
 339         SSL_CTX_set_next_proto_select_cb(client_ctx, client_npn_cb,
 340                                          client_ctx_data);
 341     }
 342     if (extra->server.alpn_protocols != NULL) {
 343         parse_protos(extra->server.alpn_protocols,
 344                      &server_ctx_data->alpn_protocols,
 345                      &server_ctx_data->alpn_protocols_len);
 346         SSL_CTX_set_alpn_select_cb(server_ctx, server_alpn_cb, server_ctx_data);
 347     }
 348     if (extra->server2.alpn_protocols != NULL) {
 349         OPENSSL_assert(server2_ctx != NULL);
 350         parse_protos(extra->server2.alpn_protocols,
 351                      &server2_ctx_data->alpn_protocols,
 352                      &server2_ctx_data->alpn_protocols_len);
 353         SSL_CTX_set_alpn_select_cb(server2_ctx, server_alpn_cb, server2_ctx_data);
 354     }
 355     if (extra->client.alpn_protocols != NULL) {
 356         unsigned char *alpn_protos = NULL;
 357         size_t alpn_protos_len;
 358         parse_protos(extra->client.alpn_protocols,
 359                      &alpn_protos, &alpn_protos_len);
 360         /* Reversed return value convention... */
 361         OPENSSL_assert(SSL_CTX_set_alpn_protos(client_ctx, alpn_protos,
 362                                                alpn_protos_len) == 0);
 363         OPENSSL_free(alpn_protos);
 364     }
 365 #endif
 366     /*
 367      * Use fixed session ticket keys so that we can decrypt a ticket created with
 368      * one CTX in another CTX. Don't address server2 for the moment.
 369      */
 370     ticket_key_len = SSL_CTX_set_tlsext_ticket_keys(server_ctx, NULL, 0);
 371     ticket_keys = OPENSSL_zalloc(ticket_key_len);
 372     OPENSSL_assert(ticket_keys != NULL);
 373     OPENSSL_assert(SSL_CTX_set_tlsext_ticket_keys(server_ctx, ticket_keys,
 374                                                   ticket_key_len) == 1);
 375     OPENSSL_free(ticket_keys);
 376 }
 377
 378 /* Configure per-SSL callbacks and other properties. */
 379 static void configure_handshake_ssl(SSL *server, SSL *client,
 380                                     const SSL_TEST_EXTRA_CONF *extra)
 381 {
 382     if (extra->client.servername != SSL_TEST_SERVERNAME_NONE)
 383         SSL_set_tlsext_host_name(client,
 384                                  ssl_servername_name(extra->client.servername));
 385 }
 386
 387
 388 typedef enum {
 389     PEER_SUCCESS,
 390     PEER_RETRY,
 391     PEER_ERROR
 392 } peer_status_t;
 393
 394 /*
 395  * RFC 5246 says:
 396  *
 397  * Note that as of TLS 1.1,
 398  *     failure to properly close a connection no longer requires that a
 399  *     session not be resumed.  This is a change from TLS 1.0 to conform
 400  *     with widespread implementation practice.
 401  *
 402  * However,
 403  * (a) OpenSSL requires that a connection be shutdown for all protocol versions.
 404  * (b) We test lower versions, too.
 405  * So we just implement shutdown. We do a full bidirectional shutdown so that we
 406  * can compare sent and received close_notify alerts and get some test coverage
 407  * for SSL_shutdown as a bonus.
 408  */
 409 static peer_status_t do_handshake_step(SSL *ssl, int shutdown)
 410 {
 411     int ret;
 412
 413     ret = shutdown ? SSL_shutdown(ssl) : SSL_do_handshake(ssl);
 414
 415     if (ret == 1) {
 416         return PEER_SUCCESS;
 417     } else if (ret == 0) {
 418         return shutdown ? PEER_RETRY : PEER_ERROR;
 419     } else {
 420         int error = SSL_get_error(ssl, ret);
 421         /* Memory bios should never block with SSL_ERROR_WANT_WRITE. */
 422         if (error == SSL_ERROR_WANT_READ)
 423             return PEER_RETRY;
 424         else
 425             return PEER_ERROR;
 426     }
 427 }
 428
 429 typedef enum {
 430     /* Both parties succeeded. */
 431     HANDSHAKE_SUCCESS,
 432     /* Client errored. */
 433     CLIENT_ERROR,
 434     /* Server errored. */
 435     SERVER_ERROR,
 436     /* Peers are in inconsistent state. */
 437     INTERNAL_ERROR,
 438     /* One or both peers not done. */
 439     HANDSHAKE_RETRY
 440 } handshake_status_t;
 441
 442 /*
 443  * Determine the handshake outcome.
 444  * last_status: the status of the peer to have acted last.
 445  * previous_status: the status of the peer that didn't act last.
 446  * client_spoke_last: 1 if the client went last.
 447  */
 448 static handshake_status_t handshake_status(peer_status_t last_status,
 449                                            peer_status_t previous_status,
 450                                            int client_spoke_last)
 451 {
 452     switch (last_status) {
 453     case PEER_SUCCESS:
 454         switch (previous_status) {
 455         case PEER_SUCCESS:
 456             /* Both succeeded. */
 457             return HANDSHAKE_SUCCESS;
 458         case PEER_RETRY:
 459             /* Let the first peer finish. */
 460             return HANDSHAKE_RETRY;
 461         case PEER_ERROR:
 462             /*
 463              * Second peer succeeded despite the fact that the first peer
 464              * already errored. This shouldn't happen.
 465              */
 466             return INTERNAL_ERROR;
 467         }
 468
 469     case PEER_RETRY:
 470         if (previous_status == PEER_RETRY) {
 471             /* Neither peer is done. */
 472             return HANDSHAKE_RETRY;
 473         } else {
 474             /*
 475              * Deadlock: second peer is waiting for more input while first
 476              * peer thinks they're done (no more input is coming).
 477              */
 478             return INTERNAL_ERROR;
 479         }
 480     case PEER_ERROR:
 481         switch (previous_status) {
 482         case PEER_SUCCESS:
 483             /*
 484              * First peer succeeded but second peer errored.
 485              * TODO(emilia): we should be able to continue here (with some
 486              * application data?) to ensure the first peer receives the
 487              * alert / close_notify.
 488              */
 489             return client_spoke_last ? CLIENT_ERROR : SERVER_ERROR;
 490         case PEER_RETRY:
 491             /* We errored; let the peer finish. */
 492             return HANDSHAKE_RETRY;
 493         case PEER_ERROR:
 494             /* Both peers errored. Return the one that errored first. */
 495             return client_spoke_last ? SERVER_ERROR : CLIENT_ERROR;
 496         }
 497     }
 498     /* Control should never reach here. */
 499     return INTERNAL_ERROR;
 500 }
 501
 502 #ifndef OPENSSL_NO_NEXTPROTONEG
 503 /* Convert unsigned char buf's that shouldn't contain any NUL-bytes to char. */
 504 static char *dup_str(const unsigned char *in, size_t len)
 505 {
 506     char *ret;
 507
 508     if(len == 0)
 509         return NULL;
 510
 511     /* Assert that the string does not contain NUL-bytes. */
 512     OPENSSL_assert(OPENSSL_strnlen((const char*)(in), len) == len);
 513     ret = OPENSSL_strndup((const char*)(in), len);
 514     OPENSSL_assert(ret != NULL);
 515     return ret;
 516 }
 517 #endif
 518
 519 static HANDSHAKE_RESULT *do_handshake_internal(
 520     SSL_CTX *server_ctx, SSL_CTX *server2_ctx, SSL_CTX *client_ctx,
 521     const SSL_TEST_EXTRA_CONF *extra, SSL_SESSION *session_in,
 522     SSL_SESSION **session_out)
 523 {
 524     SSL *server, *client;
 525     BIO *client_to_server, *server_to_client;
 526     HANDSHAKE_EX_DATA server_ex_data, client_ex_data;
 527     CTX_DATA client_ctx_data, server_ctx_data, server2_ctx_data;
 528     HANDSHAKE_RESULT *ret = HANDSHAKE_RESULT_new();
 529     int client_turn = 1, shutdown = 0;
 530     peer_status_t client_status = PEER_RETRY, server_status = PEER_RETRY;
 531     handshake_status_t status = HANDSHAKE_RETRY;
 532     unsigned char* tick = NULL;
 533     size_t tick_len = 0;
 534     SSL_SESSION* sess = NULL;
 535 #ifndef OPENSSL_NO_NEXTPROTONEG
 536     const unsigned char *proto = NULL;
 537     /* API dictates unsigned int rather than size_t. */
 538     unsigned int proto_len = 0;
 539 #endif
 540
 541     memset(&server_ctx_data, 0, sizeof(server_ctx_data));
 542     memset(&server2_ctx_data, 0, sizeof(server2_ctx_data));
 543     memset(&client_ctx_data, 0, sizeof(client_ctx_data));
 544
 545     configure_handshake_ctx(server_ctx, server2_ctx, client_ctx, extra,
 546                             &server_ctx_data, &server2_ctx_data, &client_ctx_data);
 547
 548     server = SSL_new(server_ctx);
 549     client = SSL_new(client_ctx);
 550     OPENSSL_assert(server != NULL && client != NULL);
 551
 552     configure_handshake_ssl(server, client, extra);
 553     if (session_in != NULL) {
 554         /* In case we're testing resumption without tickets. */
 555         OPENSSL_assert(SSL_CTX_add_session(server_ctx, session_in));
 556         OPENSSL_assert(SSL_set_session(client, session_in));
 557     }
 558
 559     memset(&server_ex_data, 0, sizeof(server_ex_data));
 560     memset(&client_ex_data, 0, sizeof(client_ex_data));
 561
 562     ret->result = SSL_TEST_INTERNAL_ERROR;
 563
 564     client_to_server = BIO_new(BIO_s_mem());
 565     server_to_client = BIO_new(BIO_s_mem());
 566
 567     OPENSSL_assert(client_to_server != NULL && server_to_client != NULL);
 568
 569     /* Non-blocking bio. */
 570     BIO_set_nbio(client_to_server, 1);
 571     BIO_set_nbio(server_to_client, 1);
 572
 573     SSL_set_connect_state(client);
 574     SSL_set_accept_state(server);
 575
 576     /* The bios are now owned by the SSL object. */
 577     SSL_set_bio(client, server_to_client, client_to_server);
 578     OPENSSL_assert(BIO_up_ref(server_to_client) > 0);
 579     OPENSSL_assert(BIO_up_ref(client_to_server) > 0);
 580     SSL_set_bio(server, client_to_server, server_to_client);
 581
 582     ex_data_idx = SSL_get_ex_new_index(0, "ex data", NULL, NULL, NULL);
 583     OPENSSL_assert(ex_data_idx >= 0);
 584
 585     OPENSSL_assert(SSL_set_ex_data(server, ex_data_idx,
 586                                    &server_ex_data) == 1);
 587     OPENSSL_assert(SSL_set_ex_data(client, ex_data_idx,
 588                                    &client_ex_data) == 1);
 589
 590     SSL_set_info_callback(server, &info_cb);
 591     SSL_set_info_callback(client, &info_cb);
 592
 593     /*
 594      * Half-duplex handshake loop.
 595      * Client and server speak to each other synchronously in the same process.
 596      * We use non-blocking BIOs, so whenever one peer blocks for read, it
 597      * returns PEER_RETRY to indicate that it's the other peer's turn to write.
 598      * The handshake succeeds once both peers have succeeded. If one peer
 599      * errors out, we also let the other peer retry (and presumably fail).
 600      */
 601     for(;;) {
 602         if (client_turn) {
 603             client_status = do_handshake_step(client, shutdown);
 604             status = handshake_status(client_status, server_status,
 605                                       1 /* client went last */);
 606         } else {
 607             server_status = do_handshake_step(server, shutdown);
 608             status = handshake_status(server_status, client_status,
 609                                       0 /* server went last */);
 610         }
 611
 612         switch (status) {
 613         case HANDSHAKE_SUCCESS:
 614             if (shutdown) {
 615                 ret->result = SSL_TEST_SUCCESS;
 616                 goto err;
 617             } else {
 618                 client_status = server_status = PEER_RETRY;
 619                 shutdown = 1;
 620                 client_turn = 1;
 621                 break;
 622             }
 623         case CLIENT_ERROR:
 624             ret->result = SSL_TEST_CLIENT_FAIL;
 625             goto err;
 626         case SERVER_ERROR:
 627             ret->result = SSL_TEST_SERVER_FAIL;
 628             goto err;
 629         case INTERNAL_ERROR:
 630             ret->result = SSL_TEST_INTERNAL_ERROR;
 631             goto err;
 632         case HANDSHAKE_RETRY:
 633             /* Continue. */
 634             client_turn ^= 1;
 635             break;
 636         }
 637     }
 638  err:
 639     ret->server_alert_sent = server_ex_data.alert_sent;
 640     ret->server_alert_received = client_ex_data.alert_received;
 641     ret->client_alert_sent = client_ex_data.alert_sent;
 642     ret->client_alert_received = server_ex_data.alert_received;
 643     ret->server_protocol = SSL_version(server);
 644     ret->client_protocol = SSL_version(client);
 645     ret->servername = server_ex_data.servername;
 646     if ((sess = SSL_get0_session(client)) != NULL)
 647         SSL_SESSION_get0_ticket(sess, &tick, &tick_len);
 648     if (tick == NULL || tick_len == 0)
 649         ret->session_ticket = SSL_TEST_SESSION_TICKET_NO;
 650     else
 651         ret->session_ticket = SSL_TEST_SESSION_TICKET_YES;
 652     ret->session_ticket_do_not_call = server_ex_data.session_ticket_do_not_call;
 653
 654 #ifndef OPENSSL_NO_NEXTPROTONEG
 655     SSL_get0_next_proto_negotiated(client, &proto, &proto_len);
 656     ret->client_npn_negotiated = dup_str(proto, proto_len);
 657
 658     SSL_get0_next_proto_negotiated(server, &proto, &proto_len);
 659     ret->server_npn_negotiated = dup_str(proto, proto_len);
 660
 661     SSL_get0_alpn_selected(client, &proto, &proto_len);
 662     ret->client_alpn_negotiated = dup_str(proto, proto_len);
 663
 664     SSL_get0_alpn_selected(server, &proto, &proto_len);
 665     ret->server_alpn_negotiated = dup_str(proto, proto_len);
 666 #endif
 667
 668     ret->client_resumed = SSL_session_reused(client);
 669     ret->server_resumed = SSL_session_reused(server);
 670
 671     if (session_out != NULL)
 672         *session_out = SSL_get1_session(client);
 673
 674     ctx_data_free_data(&server_ctx_data);
 675     ctx_data_free_data(&server2_ctx_data);
 676     ctx_data_free_data(&client_ctx_data);
 677
 678     SSL_free(server);
 679     SSL_free(client);
 680     return ret;
 681 }
 682
 683 HANDSHAKE_RESULT *do_handshake(SSL_CTX *server_ctx, SSL_CTX *server2_ctx,
 684                                SSL_CTX *client_ctx, SSL_CTX *resume_server_ctx,
 685                                SSL_CTX *resume_client_ctx,
 686                                const SSL_TEST_CTX *test_ctx)
 687 {
 688     HANDSHAKE_RESULT *result;
 689     SSL_SESSION *session = NULL;
 690
 691     result = do_handshake_internal(server_ctx, server2_ctx, client_ctx,
 692                                    &test_ctx->extra, NULL, &session);
 693     if (test_ctx->handshake_mode == SSL_TEST_HANDSHAKE_SIMPLE)
 694         goto end;
 695
 696     OPENSSL_assert(test_ctx->handshake_mode == SSL_TEST_HANDSHAKE_RESUME);
 697
 698     if (result->result != SSL_TEST_SUCCESS) {
 699         result->result = SSL_TEST_FIRST_HANDSHAKE_FAILED;
 700         return result;
 701     }
 702
 703     HANDSHAKE_RESULT_free(result);
 704     /* We don't support SNI on second handshake yet, so server2_ctx is NULL. */
 705     result = do_handshake_internal(resume_server_ctx, NULL, resume_client_ctx,
 706                                    &test_ctx->resume_extra, session, NULL);
 707  end:
 708     SSL_SESSION_free(session);
 709     return result;
 710 }