ssl/d1_srvr.c

   1 /* ssl/d1_srvr.c */
   2 /*
   3  * DTLS implementation written by Nagendra Modadugu
   4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 1999-2007 The OpenSSL Project.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * 3. All advertising materials mentioning features or use of this
  22  *    software must display the following acknowledgment:
  23  *    "This product includes software developed by the OpenSSL Project
  24  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  25  *
  26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  27  *    endorse or promote products derived from this software without
  28  *    prior written permission. For written permission, please contact
  29  *    openssl-core@OpenSSL.org.
  30  *
  31  * 5. Products derived from this software may not be called "OpenSSL"
  32  *    nor may "OpenSSL" appear in their names without prior written
  33  *    permission of the OpenSSL Project.
  34  *
  35  * 6. Redistributions of any form whatsoever must retain the following
  36  *    acknowledgment:
  37  *    "This product includes software developed by the OpenSSL Project
  38  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  51  * OF THE POSSIBILITY OF SUCH DAMAGE.
  52  * ====================================================================
  53  *
  54  * This product includes cryptographic software written by Eric Young
  55  * (eay@cryptsoft.com).  This product includes software written by Tim
  56  * Hudson (tjh@cryptsoft.com).
  57  *
  58  */
  59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  60  * All rights reserved.
  61  *
  62  * This package is an SSL implementation written
  63  * by Eric Young (eay@cryptsoft.com).
  64  * The implementation was written so as to conform with Netscapes SSL.
  65  *
  66  * This library is free for commercial and non-commercial use as long as
  67  * the following conditions are aheared to.  The following conditions
  68  * apply to all code found in this distribution, be it the RC4, RSA,
  69  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  70  * included with this distribution is covered by the same copyright terms
  71  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  72  *
  73  * Copyright remains Eric Young's, and as such any Copyright notices in
  74  * the code are not to be removed.
  75  * If this package is used in a product, Eric Young should be given attribution
  76  * as the author of the parts of the library used.
  77  * This can be in the form of a textual message at program startup or
  78  * in documentation (online or textual) provided with the package.
  79  *
  80  * Redistribution and use in source and binary forms, with or without
  81  * modification, are permitted provided that the following conditions
  82  * are met:
  83  * 1. Redistributions of source code must retain the copyright
  84  *    notice, this list of conditions and the following disclaimer.
  85  * 2. Redistributions in binary form must reproduce the above copyright
  86  *    notice, this list of conditions and the following disclaimer in the
  87  *    documentation and/or other materials provided with the distribution.
  88  * 3. All advertising materials mentioning features or use of this software
  89  *    must display the following acknowledgement:
  90  *    "This product includes cryptographic software written by
  91  *     Eric Young (eay@cryptsoft.com)"
  92  *    The word 'cryptographic' can be left out if the rouines from the library
  93  *    being used are not cryptographic related :-).
  94  * 4. If you include any Windows specific code (or a derivative thereof) from
  95  *    the apps directory (application code) you must include an acknowledgement:
  96  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  97  *
  98  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  99  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 100  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 101  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 102  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 103  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 104  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 105  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 106  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 107  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 108  * SUCH DAMAGE.
 109  *
 110  * The licence and distribution terms for any publically available version or
 111  * derivative of this code cannot be changed.  i.e. this code cannot simply be
 112  * copied and put under another distribution licence
 113  * [including the GNU Public Licence.]
 114  */
 115
 116 #include <stdio.h>
 117 #include "ssl_locl.h"
 118 #include <openssl/buffer.h>
 119 #include <openssl/rand.h>
 120 #include <openssl/objects.h>
 121 #include <openssl/evp.h>
 122 #include <openssl/x509.h>
 123 #include <openssl/md5.h>
 124 #include <openssl/bn.h>
 125 #ifndef OPENSSL_NO_DH
 126 # include <openssl/dh.h>
 127 #endif
 128
 129 static const SSL_METHOD *dtls1_get_server_method(int ver);
 130 static int dtls1_send_hello_verify_request(SSL *s);
 131
 132 static const SSL_METHOD *dtls1_get_server_method(int ver)
 133 {
 134     if (ver == DTLS1_VERSION)
 135         return (DTLSv1_server_method());
 136     else if (ver == DTLS1_2_VERSION)
 137         return (DTLSv1_2_server_method());
 138     else
 139         return (NULL);
 140 }
 141
 142 IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
 143                           DTLSv1_server_method,
 144                           dtls1_accept,
 145                           ssl_undefined_function,
 146                           dtls1_get_server_method, DTLSv1_enc_data)
 147
 148     IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
 149                           DTLSv1_2_server_method,
 150                           dtls1_accept,
 151                           ssl_undefined_function,
 152                           dtls1_get_server_method, DTLSv1_2_enc_data)
 153
 154     IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
 155                           DTLS_server_method,
 156                           dtls1_accept,
 157                           ssl_undefined_function,
 158                           dtls1_get_server_method, DTLSv1_2_enc_data)
 159
 160 int dtls1_accept(SSL *s)
 161 {
 162     BUF_MEM *buf;
 163     unsigned long Time = (unsigned long)time(NULL);
 164     void (*cb) (const SSL *ssl, int type, int val) = NULL;
 165     unsigned long alg_k;
 166     int ret = -1;
 167     int new_state, state, skip = 0;
 168     int listen;
 169 #ifndef OPENSSL_NO_SCTP
 170     unsigned char sctpauthkey[64];
 171     char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
 172 #endif
 173
 174     RAND_add(&Time, sizeof(Time), 0);
 175     ERR_clear_error();
 176     clear_sys_error();
 177
 178     if (s->info_callback != NULL)
 179         cb = s->info_callback;
 180     else if (s->ctx->info_callback != NULL)
 181         cb = s->ctx->info_callback;
 182
 183     listen = s->d1->listen;
 184
 185     /* init things to blank */
 186     s->in_handshake++;
 187     if (!SSL_in_init(s) || SSL_in_before(s)) {
 188         if (!SSL_clear(s))
 189             return -1;
 190     }
 191
 192     s->d1->listen = listen;
 193 #ifndef OPENSSL_NO_SCTP
 194     /*
 195      * Notify SCTP BIO socket to enter handshake mode and prevent stream
 196      * identifier other than 0. Will be ignored if no SCTP is used.
 197      */
 198     BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
 199              s->in_handshake, NULL);
 200 #endif
 201
 202 #ifndef OPENSSL_NO_HEARTBEATS
 203     /*
 204      * If we're awaiting a HeartbeatResponse, pretend we already got and
 205      * don't await it anymore, because Heartbeats don't make sense during
 206      * handshakes anyway.
 207      */
 208     if (s->tlsext_hb_pending) {
 209         dtls1_stop_timer(s);
 210         s->tlsext_hb_pending = 0;
 211         s->tlsext_hb_seq++;
 212     }
 213 #endif
 214
 215     for (;;) {
 216         state = s->state;
 217
 218         switch (s->state) {
 219         case SSL_ST_RENEGOTIATE:
 220             s->renegotiate = 1;
 221             /* s->state=SSL_ST_ACCEPT; */
 222
 223         case SSL_ST_BEFORE:
 224         case SSL_ST_ACCEPT:
 225         case SSL_ST_BEFORE | SSL_ST_ACCEPT:
 226         case SSL_ST_OK | SSL_ST_ACCEPT:
 227
 228             s->server = 1;
 229             if (cb != NULL)
 230                 cb(s, SSL_CB_HANDSHAKE_START, 1);
 231
 232             if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
 233                 SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
 234                 return -1;
 235             }
 236             s->type = SSL_ST_ACCEPT;
 237
 238             if (s->init_buf == NULL) {
 239                 if ((buf = BUF_MEM_new()) == NULL) {
 240                     ret = -1;
 241                     s->state = SSL_ST_ERR;
 242                     goto end;
 243                 }
 244                 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
 245                     BUF_MEM_free(buf);
 246                     ret = -1;
 247                     s->state = SSL_ST_ERR;
 248                     goto end;
 249                 }
 250                 s->init_buf = buf;
 251             }
 252
 253             if (!ssl3_setup_buffers(s)) {
 254                 ret = -1;
 255                 s->state = SSL_ST_ERR;
 256                 goto end;
 257             }
 258
 259             s->init_num = 0;
 260             s->d1->change_cipher_spec_ok = 0;
 261             /*
 262              * Should have been reset by ssl3_get_finished, too.
 263              */
 264             s->s3->change_cipher_spec = 0;
 265
 266             if (s->state != SSL_ST_RENEGOTIATE) {
 267                 /*
 268                  * Ok, we now need to push on a buffering BIO so that the
 269                  * output is sent in a way that TCP likes :-) ...but not with
 270                  * SCTP :-)
 271                  */
 272 #ifndef OPENSSL_NO_SCTP
 273                 if (!BIO_dgram_is_sctp(SSL_get_wbio(s)))
 274 #endif
 275                     if (!ssl_init_wbio_buffer(s, 1)) {
 276                         ret = -1;
 277                         s->state = SSL_ST_ERR;
 278                         goto end;
 279                     }
 280
 281                 ssl3_init_finished_mac(s);
 282                 s->state = SSL3_ST_SR_CLNT_HELLO_A;
 283                 s->ctx->stats.sess_accept++;
 284             } else {
 285                 /*
 286                  * s->state == SSL_ST_RENEGOTIATE, we will just send a
 287                  * HelloRequest
 288                  */
 289                 s->ctx->stats.sess_accept_renegotiate++;
 290                 s->state = SSL3_ST_SW_HELLO_REQ_A;
 291             }
 292
 293             break;
 294
 295         case SSL3_ST_SW_HELLO_REQ_A:
 296         case SSL3_ST_SW_HELLO_REQ_B:
 297
 298             s->shutdown = 0;
 299             dtls1_clear_record_buffer(s);
 300             dtls1_start_timer(s);
 301             ret = ssl3_send_hello_request(s);
 302             if (ret <= 0)
 303                 goto end;
 304             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 305             s->state = SSL3_ST_SW_FLUSH;
 306             s->init_num = 0;
 307
 308             ssl3_init_finished_mac(s);
 309             break;
 310
 311         case SSL3_ST_SW_HELLO_REQ_C:
 312             s->state = SSL_ST_OK;
 313             break;
 314
 315         case SSL3_ST_SR_CLNT_HELLO_A:
 316         case SSL3_ST_SR_CLNT_HELLO_B:
 317         case SSL3_ST_SR_CLNT_HELLO_C:
 318
 319             s->shutdown = 0;
 320             ret = ssl3_get_client_hello(s);
 321             if (ret <= 0)
 322                 goto end;
 323             dtls1_stop_timer(s);
 324
 325             if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
 326                 s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
 327             else
 328                 s->state = SSL3_ST_SW_SRVR_HELLO_A;
 329
 330             s->init_num = 0;
 331
 332             /*
 333              * Reflect ClientHello sequence to remain stateless while
 334              * listening
 335              */
 336             if (listen) {
 337                 DTLS_RECORD_LAYER_resync_write(&s->rlayer);
 338             }
 339
 340             /* If we're just listening, stop here */
 341             if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
 342                 ret = 2;
 343                 s->d1->listen = 0;
 344                 /*
 345                  * Set expected sequence numbers to continue the handshake.
 346                  */
 347                 s->d1->handshake_read_seq = 2;
 348                 s->d1->handshake_write_seq = 1;
 349                 s->d1->next_handshake_write_seq = 1;
 350                 goto end;
 351             }
 352
 353             break;
 354
 355         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
 356         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
 357
 358             ret = dtls1_send_hello_verify_request(s);
 359             if (ret <= 0)
 360                 goto end;
 361             s->state = SSL3_ST_SW_FLUSH;
 362             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 363
 364             /* HelloVerifyRequest resets Finished MAC */
 365             if (s->version != DTLS1_BAD_VER)
 366                 ssl3_init_finished_mac(s);
 367             break;
 368
 369 #ifndef OPENSSL_NO_SCTP
 370         case DTLS1_SCTP_ST_SR_READ_SOCK:
 371
 372             if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
 373                 s->s3->in_read_app_data = 2;
 374                 s->rwstate = SSL_READING;
 375                 BIO_clear_retry_flags(SSL_get_rbio(s));
 376                 BIO_set_retry_read(SSL_get_rbio(s));
 377                 ret = -1;
 378                 goto end;
 379             }
 380
 381             s->state = SSL3_ST_SR_FINISHED_A;
 382             break;
 383
 384         case DTLS1_SCTP_ST_SW_WRITE_SOCK:
 385             ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
 386             if (ret < 0)
 387                 goto end;
 388
 389             if (ret == 0) {
 390                 if (s->d1->next_state != SSL_ST_OK) {
 391                     s->s3->in_read_app_data = 2;
 392                     s->rwstate = SSL_READING;
 393                     BIO_clear_retry_flags(SSL_get_rbio(s));
 394                     BIO_set_retry_read(SSL_get_rbio(s));
 395                     ret = -1;
 396                     goto end;
 397                 }
 398             }
 399
 400             s->state = s->d1->next_state;
 401             break;
 402 #endif
 403
 404         case SSL3_ST_SW_SRVR_HELLO_A:
 405         case SSL3_ST_SW_SRVR_HELLO_B:
 406             s->renegotiate = 2;
 407             dtls1_start_timer(s);
 408             ret = ssl3_send_server_hello(s);
 409             if (ret <= 0)
 410                 goto end;
 411
 412             if (s->hit) {
 413 #ifndef OPENSSL_NO_SCTP
 414                 /*
 415                  * Add new shared key for SCTP-Auth, will be ignored if no
 416                  * SCTP used.
 417                  */
 418                 snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 419                          DTLS1_SCTP_AUTH_LABEL);
 420
 421                 SSL_export_keying_material(s, sctpauthkey,
 422                                            sizeof(sctpauthkey), labelbuffer,
 423                                            sizeof(labelbuffer), NULL, 0, 0);
 424
 425                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 426                          sizeof(sctpauthkey), sctpauthkey);
 427 #endif
 428 #ifndef OPENSSL_NO_TLSEXT
 429                 if (s->tlsext_ticket_expected)
 430                     s->state = SSL3_ST_SW_SESSION_TICKET_A;
 431                 else
 432                     s->state = SSL3_ST_SW_CHANGE_A;
 433 #else
 434                 s->state = SSL3_ST_SW_CHANGE_A;
 435 #endif
 436             } else
 437                 s->state = SSL3_ST_SW_CERT_A;
 438             s->init_num = 0;
 439             break;
 440
 441         case SSL3_ST_SW_CERT_A:
 442         case SSL3_ST_SW_CERT_B:
 443             /* Check if it is anon DH or normal PSK */
 444             if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
 445                 && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 446                 dtls1_start_timer(s);
 447                 ret = ssl3_send_server_certificate(s);
 448                 if (ret <= 0)
 449                     goto end;
 450 #ifndef OPENSSL_NO_TLSEXT
 451                 if (s->tlsext_status_expected)
 452                     s->state = SSL3_ST_SW_CERT_STATUS_A;
 453                 else
 454                     s->state = SSL3_ST_SW_KEY_EXCH_A;
 455             } else {
 456                 skip = 1;
 457                 s->state = SSL3_ST_SW_KEY_EXCH_A;
 458             }
 459 #else
 460             } else
 461                 skip = 1;
 462
 463             s->state = SSL3_ST_SW_KEY_EXCH_A;
 464 #endif
 465             s->init_num = 0;
 466             break;
 467
 468         case SSL3_ST_SW_KEY_EXCH_A:
 469         case SSL3_ST_SW_KEY_EXCH_B:
 470             alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 471
 472             /*
 473              * clear this, it may get reset by
 474              * send_server_key_exchange
 475              */
 476             s->s3->tmp.use_rsa_tmp = 0;
 477
 478             /*
 479              * only send if a DH key exchange or RSA but we have a sign only
 480              * certificate
 481              */
 482             if (0
 483                 /*
 484                  * PSK: send ServerKeyExchange if PSK identity hint if
 485                  * provided
 486                  */
 487 #ifndef OPENSSL_NO_PSK
 488                 || ((alg_k & SSL_kPSK) && s->ctx->psk_identity_hint)
 489 #endif
 490                 || (alg_k & SSL_kDHE)
 491                 || (alg_k & SSL_kECDHE)
 492                 || ((alg_k & SSL_kRSA)
 493                     && (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
 494                         || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
 495                             && EVP_PKEY_size(s->cert->pkeys
 496                                              [SSL_PKEY_RSA_ENC].privatekey) *
 497                             8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
 498                         )
 499                     )
 500                 )
 501                 ) {
 502                 dtls1_start_timer(s);
 503                 ret = ssl3_send_server_key_exchange(s);
 504                 if (ret <= 0)
 505                     goto end;
 506             } else
 507                 skip = 1;
 508
 509             s->state = SSL3_ST_SW_CERT_REQ_A;
 510             s->init_num = 0;
 511             break;
 512
 513         case SSL3_ST_SW_CERT_REQ_A:
 514         case SSL3_ST_SW_CERT_REQ_B:
 515             if (                /* don't request cert unless asked for it: */
 516                    !(s->verify_mode & SSL_VERIFY_PEER) ||
 517                    /*
 518                     * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
 519                     * during re-negotiation:
 520                     */
 521                    ((s->session->peer != NULL) &&
 522                     (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
 523                    /*
 524                     * never request cert in anonymous ciphersuites (see
 525                     * section "Certificate request" in SSL 3 drafts and in
 526                     * RFC 2246):
 527                     */
 528                    ((s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) &&
 529                    /*
 530                     * ... except when the application insists on
 531                     * verification (against the specs, but s3_clnt.c accepts
 532                     * this for SSL 3)
 533                     */
 534                    !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
 535                    /*
 536                     * With normal PSK Certificates and Certificate Requests
 537                     * are omitted
 538                     */
 539                    || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 540                 /* no cert request */
 541                 skip = 1;
 542                 s->s3->tmp.cert_request = 0;
 543                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 544 #ifndef OPENSSL_NO_SCTP
 545                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 546                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 547                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 548                 }
 549 #endif
 550             } else {
 551                 s->s3->tmp.cert_request = 1;
 552                 dtls1_start_timer(s);
 553                 ret = ssl3_send_certificate_request(s);
 554                 if (ret <= 0)
 555                     goto end;
 556                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 557 # ifndef OPENSSL_NO_SCTP
 558                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 559                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 560                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 561                 }
 562 # endif
 563                 s->init_num = 0;
 564             }
 565             break;
 566
 567         case SSL3_ST_SW_SRVR_DONE_A:
 568         case SSL3_ST_SW_SRVR_DONE_B:
 569             dtls1_start_timer(s);
 570             ret = ssl3_send_server_done(s);
 571             if (ret <= 0)
 572                 goto end;
 573             s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
 574             s->state = SSL3_ST_SW_FLUSH;
 575             s->init_num = 0;
 576             break;
 577
 578         case SSL3_ST_SW_FLUSH:
 579             s->rwstate = SSL_WRITING;
 580             if (BIO_flush(s->wbio) <= 0) {
 581                 /*
 582                  * If the write error was fatal, stop trying
 583                  */
 584                 if (!BIO_should_retry(s->wbio)) {
 585                     s->rwstate = SSL_NOTHING;
 586                     s->state = s->s3->tmp.next_state;
 587                 }
 588
 589                 ret = -1;
 590                 goto end;
 591             }
 592             s->rwstate = SSL_NOTHING;
 593             s->state = s->s3->tmp.next_state;
 594             break;
 595
 596         case SSL3_ST_SR_CERT_A:
 597         case SSL3_ST_SR_CERT_B:
 598             if (s->s3->tmp.cert_request) {
 599                 ret = ssl3_get_client_certificate(s);
 600                 if (ret <= 0)
 601                     goto end;
 602             }
 603             s->init_num = 0;
 604             s->state = SSL3_ST_SR_KEY_EXCH_A;
 605             break;
 606
 607         case SSL3_ST_SR_KEY_EXCH_A:
 608         case SSL3_ST_SR_KEY_EXCH_B:
 609             ret = ssl3_get_client_key_exchange(s);
 610             if (ret <= 0)
 611                 goto end;
 612 #ifndef OPENSSL_NO_SCTP
 613             /*
 614              * Add new shared key for SCTP-Auth, will be ignored if no SCTP
 615              * used.
 616              */
 617             snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 618                      DTLS1_SCTP_AUTH_LABEL);
 619
 620             SSL_export_keying_material(s, sctpauthkey,
 621                                        sizeof(sctpauthkey), labelbuffer,
 622                                        sizeof(labelbuffer), NULL, 0, 0);
 623
 624             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 625                      sizeof(sctpauthkey), sctpauthkey);
 626 #endif
 627
 628             s->state = SSL3_ST_SR_CERT_VRFY_A;
 629             s->init_num = 0;
 630
 631             if (ret == 2) {
 632                 /*
 633                  * For the ECDH ciphersuites when the client sends its ECDH
 634                  * pub key in a certificate, the CertificateVerify message is
 635                  * not sent.
 636                  */
 637                 s->state = SSL3_ST_SR_FINISHED_A;
 638                 s->init_num = 0;
 639             } else if (SSL_USE_SIGALGS(s)) {
 640                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 641                 s->init_num = 0;
 642                 if (!s->session->peer)
 643                     break;
 644                 if (!s->s3->handshake_buffer) {
 645                     SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
 646                     s->state = SSL_ST_ERR;
 647                     return -1;
 648                 }
 649                 /*
 650                  * For sigalgs freeze the handshake buffer. If we support
 651                  * extms we've done this already.
 652                  */
 653                 if (!(s->s3->flags & SSL_SESS_FLAG_EXTMS)) {
 654                     s->s3->flags |= TLS1_FLAGS_KEEP_HANDSHAKE;
 655                     if (!ssl3_digest_cached_records(s)) {
 656                         s->state = SSL_ST_ERR;
 657                         return -1;
 658                     }
 659                 }
 660             } else {
 661                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 662                 s->init_num = 0;
 663
 664                 /*
 665                  * We need to get hashes here so if there is a client cert,
 666                  * it can be verified
 667                  */
 668                 s->method->ssl3_enc->cert_verify_mac(s,
 669                                                      NID_md5,
 670                                                      &(s->s3->
 671                                                        tmp.cert_verify_md
 672                                                        [0]));
 673                 s->method->ssl3_enc->cert_verify_mac(s, NID_sha1,
 674                                                      &(s->s3->
 675                                                        tmp.cert_verify_md
 676                                                        [MD5_DIGEST_LENGTH]));
 677             }
 678             break;
 679
 680         case SSL3_ST_SR_CERT_VRFY_A:
 681         case SSL3_ST_SR_CERT_VRFY_B:
 682             ret = ssl3_get_cert_verify(s);
 683             if (ret <= 0)
 684                 goto end;
 685 #ifndef OPENSSL_NO_SCTP
 686             if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
 687                 state == SSL_ST_RENEGOTIATE)
 688                 s->state = DTLS1_SCTP_ST_SR_READ_SOCK;
 689             else
 690 #endif
 691                 s->state = SSL3_ST_SR_FINISHED_A;
 692             s->init_num = 0;
 693             break;
 694
 695         case SSL3_ST_SR_FINISHED_A:
 696         case SSL3_ST_SR_FINISHED_B:
 697             /*
 698              * Enable CCS. Receiving a CCS clears the flag, so make
 699              * sure not to re-enable it to ban duplicates. This *should* be the
 700              * first time we have received one - but we check anyway to be
 701              * cautious.
 702              * s->s3->change_cipher_spec is set when a CCS is
 703              * processed in d1_pkt.c, and remains set until
 704              * the client's Finished message is read.
 705              */
 706             if (!s->s3->change_cipher_spec)
 707                 s->d1->change_cipher_spec_ok = 1;
 708             ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
 709                                     SSL3_ST_SR_FINISHED_B);
 710             if (ret <= 0)
 711                 goto end;
 712             dtls1_stop_timer(s);
 713             if (s->hit)
 714                 s->state = SSL_ST_OK;
 715 #ifndef OPENSSL_NO_TLSEXT
 716             else if (s->tlsext_ticket_expected)
 717                 s->state = SSL3_ST_SW_SESSION_TICKET_A;
 718 #endif
 719             else
 720                 s->state = SSL3_ST_SW_CHANGE_A;
 721             s->init_num = 0;
 722             break;
 723
 724 #ifndef OPENSSL_NO_TLSEXT
 725         case SSL3_ST_SW_SESSION_TICKET_A:
 726         case SSL3_ST_SW_SESSION_TICKET_B:
 727             ret = ssl3_send_newsession_ticket(s);
 728             if (ret <= 0)
 729                 goto end;
 730             s->state = SSL3_ST_SW_CHANGE_A;
 731             s->init_num = 0;
 732             break;
 733
 734         case SSL3_ST_SW_CERT_STATUS_A:
 735         case SSL3_ST_SW_CERT_STATUS_B:
 736             ret = ssl3_send_cert_status(s);
 737             if (ret <= 0)
 738                 goto end;
 739             s->state = SSL3_ST_SW_KEY_EXCH_A;
 740             s->init_num = 0;
 741             break;
 742
 743 #endif
 744
 745         case SSL3_ST_SW_CHANGE_A:
 746         case SSL3_ST_SW_CHANGE_B:
 747
 748             s->session->cipher = s->s3->tmp.new_cipher;
 749             if (!s->method->ssl3_enc->setup_key_block(s)) {
 750                 ret = -1;
 751                 s->state = SSL_ST_ERR;
 752                 goto end;
 753             }
 754
 755             ret = dtls1_send_change_cipher_spec(s,
 756                                                 SSL3_ST_SW_CHANGE_A,
 757                                                 SSL3_ST_SW_CHANGE_B);
 758
 759             if (ret <= 0)
 760                 goto end;
 761
 762 #ifndef OPENSSL_NO_SCTP
 763             if (!s->hit) {
 764                 /*
 765                  * Change to new shared key of SCTP-Auth, will be ignored if
 766                  * no SCTP used.
 767                  */
 768                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 769                          0, NULL);
 770             }
 771 #endif
 772
 773             s->state = SSL3_ST_SW_FINISHED_A;
 774             s->init_num = 0;
 775
 776             if (!s->method->ssl3_enc->change_cipher_state(s,
 777                                                           SSL3_CHANGE_CIPHER_SERVER_WRITE))
 778             {
 779                 ret = -1;
 780                 s->state = SSL_ST_ERR;
 781                 goto end;
 782             }
 783
 784             dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
 785             break;
 786
 787         case SSL3_ST_SW_FINISHED_A:
 788         case SSL3_ST_SW_FINISHED_B:
 789             ret = ssl3_send_finished(s,
 790                                      SSL3_ST_SW_FINISHED_A,
 791                                      SSL3_ST_SW_FINISHED_B,
 792                                      s->method->
 793                                      ssl3_enc->server_finished_label,
 794                                      s->method->
 795                                      ssl3_enc->server_finished_label_len);
 796             if (ret <= 0)
 797                 goto end;
 798             s->state = SSL3_ST_SW_FLUSH;
 799             if (s->hit) {
 800                 s->s3->tmp.next_state = SSL3_ST_SR_FINISHED_A;
 801
 802 #ifndef OPENSSL_NO_SCTP
 803                 /*
 804                  * Change to new shared key of SCTP-Auth, will be ignored if
 805                  * no SCTP used.
 806                  */
 807                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 808                          0, NULL);
 809 #endif
 810             } else {
 811                 s->s3->tmp.next_state = SSL_ST_OK;
 812 #ifndef OPENSSL_NO_SCTP
 813                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 814                     s->d1->next_state = s->s3->tmp.next_state;
 815                     s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 816                 }
 817 #endif
 818             }
 819             s->init_num = 0;
 820             break;
 821
 822         case SSL_ST_OK:
 823             /* clean a few things up */
 824             ssl3_cleanup_key_block(s);
 825
 826             /* remove buffering on output */
 827             ssl_free_wbio_buffer(s);
 828
 829             s->init_num = 0;
 830
 831             if (s->renegotiate == 2) { /* skipped if we just sent a
 832                                         * HelloRequest */
 833                 s->renegotiate = 0;
 834                 s->new_session = 0;
 835
 836                 ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
 837
 838                 s->ctx->stats.sess_accept_good++;
 839                 /* s->server=1; */
 840                 s->handshake_func = dtls1_accept;
 841
 842                 if (cb != NULL)
 843                     cb(s, SSL_CB_HANDSHAKE_DONE, 1);
 844             }
 845
 846             ret = 1;
 847
 848             /* done handshaking, next message is client hello */
 849             s->d1->handshake_read_seq = 0;
 850             /* next message is server hello */
 851             s->d1->handshake_write_seq = 0;
 852             s->d1->next_handshake_write_seq = 0;
 853             goto end;
 854             /* break; */
 855
 856         case SSL_ST_ERR:
 857         default:
 858             SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
 859             ret = -1;
 860             goto end;
 861             /* break; */
 862         }
 863
 864         if (!s->s3->tmp.reuse_message && !skip) {
 865             if (s->debug) {
 866                 if ((ret = BIO_flush(s->wbio)) <= 0)
 867                     goto end;
 868             }
 869
 870             if ((cb != NULL) && (s->state != state)) {
 871                 new_state = s->state;
 872                 s->state = state;
 873                 cb(s, SSL_CB_ACCEPT_LOOP, 1);
 874                 s->state = new_state;
 875             }
 876         }
 877         skip = 0;
 878     }
 879  end:
 880     /* BIO_flush(s->wbio); */
 881
 882     s->in_handshake--;
 883 #ifndef OPENSSL_NO_SCTP
 884     /*
 885      * Notify SCTP BIO socket to leave handshake mode and prevent stream
 886      * identifier other than 0. Will be ignored if no SCTP is used.
 887      */
 888     BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
 889              s->in_handshake, NULL);
 890 #endif
 891
 892     if (cb != NULL)
 893         cb(s, SSL_CB_ACCEPT_EXIT, ret);
 894     return (ret);
 895 }
 896
 897 int dtls1_send_hello_verify_request(SSL *s)
 898 {
 899     unsigned int msg_len;
 900     unsigned char *msg, *buf, *p;
 901
 902     if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
 903         buf = (unsigned char *)s->init_buf->data;
 904
 905         msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
 906         /* Always use DTLS 1.0 version: see RFC 6347 */
 907         *(p++) = DTLS1_VERSION >> 8;
 908         *(p++) = DTLS1_VERSION & 0xFF;
 909
 910         if (s->ctx->app_gen_cookie_cb == NULL ||
 911             s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
 912                                       &(s->d1->cookie_len)) == 0) {
 913             SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
 914                    ERR_R_INTERNAL_ERROR);
 915             s->state = SSL_ST_ERR;
 916             return 0;
 917         }
 918
 919         *(p++) = (unsigned char)s->d1->cookie_len;
 920         memcpy(p, s->d1->cookie, s->d1->cookie_len);
 921         p += s->d1->cookie_len;
 922         msg_len = p - msg;
 923
 924         dtls1_set_message_header(s, buf,
 925                                  DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0,
 926                                  msg_len);
 927
 928         s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
 929         /* number of bytes to write */
 930         s->init_num = p - buf;
 931         s->init_off = 0;
 932     }
 933
 934     /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
 935     return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
 936 }