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 == DTLS_ANY_VERSION)
 135         return DTLS_server_method();
 136     else if (ver == DTLS1_VERSION)
 137         return DTLSv1_server_method();
 138     else if (ver == DTLS1_2_VERSION)
 139         return DTLSv1_2_server_method();
 140     else
 141         return NULL;
 142 }
 143
 144 IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
 145                           DTLSv1_server_method,
 146                           dtls1_accept,
 147                           ssl_undefined_function,
 148                           dtls1_get_server_method, DTLSv1_enc_data)
 149
 150 IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
 151                           DTLSv1_2_server_method,
 152                           dtls1_accept,
 153                           ssl_undefined_function,
 154                           dtls1_get_server_method, DTLSv1_2_enc_data)
 155
 156 IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
 157                           DTLS_server_method,
 158                           dtls1_accept,
 159                           ssl_undefined_function,
 160                           dtls1_get_server_method, DTLSv1_2_enc_data)
 161
 162 int dtls1_accept(SSL *s)
 163 {
 164     BUF_MEM *buf;
 165     unsigned long Time = (unsigned long)time(NULL);
 166     void (*cb) (const SSL *ssl, int type, int val) = NULL;
 167     unsigned long alg_k;
 168     int ret = -1;
 169     int new_state, state, skip = 0;
 170     int listen;
 171 #ifndef OPENSSL_NO_SCTP
 172     unsigned char sctpauthkey[64];
 173     char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
 174 #endif
 175
 176     RAND_add(&Time, sizeof(Time), 0);
 177     ERR_clear_error();
 178     clear_sys_error();
 179
 180     if (s->info_callback != NULL)
 181         cb = s->info_callback;
 182     else if (s->ctx->info_callback != NULL)
 183         cb = s->ctx->info_callback;
 184
 185     listen = s->d1->listen;
 186
 187     /* init things to blank */
 188     s->in_handshake++;
 189     if (!SSL_in_init(s) || SSL_in_before(s))
 190         SSL_clear(s);
 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     if (s->cert == NULL) {
 203         SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_NO_CERTIFICATE_SET);
 204         return (-1);
 205     }
 206 #ifndef OPENSSL_NO_HEARTBEATS
 207     /*
 208      * If we're awaiting a HeartbeatResponse, pretend we already got and
 209      * don't await it anymore, because Heartbeats don't make sense during
 210      * handshakes anyway.
 211      */
 212     if (s->tlsext_hb_pending) {
 213         dtls1_stop_timer(s);
 214         s->tlsext_hb_pending = 0;
 215         s->tlsext_hb_seq++;
 216     }
 217 #endif
 218
 219     for (;;) {
 220         state = s->state;
 221
 222         switch (s->state) {
 223         case SSL_ST_RENEGOTIATE:
 224             s->renegotiate = 1;
 225             /* s->state=SSL_ST_ACCEPT; */
 226
 227         case SSL_ST_BEFORE:
 228         case SSL_ST_ACCEPT:
 229         case SSL_ST_BEFORE | SSL_ST_ACCEPT:
 230         case SSL_ST_OK | SSL_ST_ACCEPT:
 231
 232             s->server = 1;
 233             if (cb != NULL)
 234                 cb(s, SSL_CB_HANDSHAKE_START, 1);
 235
 236             if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
 237                 SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
 238                 return -1;
 239             }
 240             s->type = SSL_ST_ACCEPT;
 241
 242             if (s->init_buf == NULL) {
 243                 if ((buf = BUF_MEM_new()) == NULL) {
 244                     ret = -1;
 245                     s->state = SSL_ST_ERR;
 246                     goto end;
 247                 }
 248                 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
 249                     BUF_MEM_free(buf);
 250                     ret = -1;
 251                     s->state = SSL_ST_ERR;
 252                     goto end;
 253                 }
 254                 s->init_buf = buf;
 255             }
 256
 257             if (!ssl3_setup_buffers(s)) {
 258                 ret = -1;
 259                 s->state = SSL_ST_ERR;
 260                 goto end;
 261             }
 262
 263             s->init_num = 0;
 264             s->d1->change_cipher_spec_ok = 0;
 265             /*
 266              * Should have been reset by ssl3_get_finished, too.
 267              */
 268             s->s3->change_cipher_spec = 0;
 269
 270             if (s->state != SSL_ST_RENEGOTIATE) {
 271                 /*
 272                  * Ok, we now need to push on a buffering BIO so that the
 273                  * output is sent in a way that TCP likes :-) ...but not with
 274                  * SCTP :-)
 275                  */
 276 #ifndef OPENSSL_NO_SCTP
 277                 if (!BIO_dgram_is_sctp(SSL_get_wbio(s)))
 278 #endif
 279                     if (!ssl_init_wbio_buffer(s, 1)) {
 280                         ret = -1;
 281                         s->state = SSL_ST_ERR;
 282                         goto end;
 283                     }
 284
 285                 ssl3_init_finished_mac(s);
 286                 s->state = SSL3_ST_SR_CLNT_HELLO_A;
 287                 s->ctx->stats.sess_accept++;
 288             } else {
 289                 /*
 290                  * s->state == SSL_ST_RENEGOTIATE, we will just send a
 291                  * HelloRequest
 292                  */
 293                 s->ctx->stats.sess_accept_renegotiate++;
 294                 s->state = SSL3_ST_SW_HELLO_REQ_A;
 295             }
 296
 297             break;
 298
 299         case SSL3_ST_SW_HELLO_REQ_A:
 300         case SSL3_ST_SW_HELLO_REQ_B:
 301
 302             s->shutdown = 0;
 303             dtls1_clear_record_buffer(s);
 304             dtls1_start_timer(s);
 305             ret = ssl3_send_hello_request(s);
 306             if (ret <= 0)
 307                 goto end;
 308             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 309             s->state = SSL3_ST_SW_FLUSH;
 310             s->init_num = 0;
 311
 312             ssl3_init_finished_mac(s);
 313             break;
 314
 315         case SSL3_ST_SW_HELLO_REQ_C:
 316             s->state = SSL_ST_OK;
 317             break;
 318
 319         case SSL3_ST_SR_CLNT_HELLO_A:
 320         case SSL3_ST_SR_CLNT_HELLO_B:
 321         case SSL3_ST_SR_CLNT_HELLO_C:
 322
 323             s->shutdown = 0;
 324             ret = ssl3_get_client_hello(s);
 325             if (ret <= 0)
 326                 goto end;
 327             dtls1_stop_timer(s);
 328
 329             if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
 330                 s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
 331             else
 332                 s->state = SSL3_ST_SW_SRVR_HELLO_A;
 333
 334             s->init_num = 0;
 335
 336             /*
 337              * Reflect ClientHello sequence to remain stateless while
 338              * listening
 339              */
 340             if (listen) {
 341                 memcpy(s->s3->write_sequence, s->s3->read_sequence,
 342                        sizeof(s->s3->write_sequence));
 343             }
 344
 345             /* If we're just listening, stop here */
 346             if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
 347                 ret = 2;
 348                 s->d1->listen = 0;
 349                 /*
 350                  * Set expected sequence numbers to continue the handshake.
 351                  */
 352                 s->d1->handshake_read_seq = 2;
 353                 s->d1->handshake_write_seq = 1;
 354                 s->d1->next_handshake_write_seq = 1;
 355                 goto end;
 356             }
 357
 358             break;
 359
 360         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
 361         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
 362
 363             ret = dtls1_send_hello_verify_request(s);
 364             if (ret <= 0)
 365                 goto end;
 366             s->state = SSL3_ST_SW_FLUSH;
 367             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 368
 369             /* HelloVerifyRequest resets Finished MAC */
 370             if (s->version != DTLS1_BAD_VER)
 371                 ssl3_init_finished_mac(s);
 372             break;
 373
 374 #ifndef OPENSSL_NO_SCTP
 375         case DTLS1_SCTP_ST_SR_READ_SOCK:
 376
 377             if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
 378                 s->s3->in_read_app_data = 2;
 379                 s->rwstate = SSL_READING;
 380                 BIO_clear_retry_flags(SSL_get_rbio(s));
 381                 BIO_set_retry_read(SSL_get_rbio(s));
 382                 ret = -1;
 383                 goto end;
 384             }
 385
 386             s->state = SSL3_ST_SR_FINISHED_A;
 387             break;
 388
 389         case DTLS1_SCTP_ST_SW_WRITE_SOCK:
 390             ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
 391             if (ret < 0)
 392                 goto end;
 393
 394             if (ret == 0) {
 395                 if (s->d1->next_state != SSL_ST_OK) {
 396                     s->s3->in_read_app_data = 2;
 397                     s->rwstate = SSL_READING;
 398                     BIO_clear_retry_flags(SSL_get_rbio(s));
 399                     BIO_set_retry_read(SSL_get_rbio(s));
 400                     ret = -1;
 401                     goto end;
 402                 }
 403             }
 404
 405             s->state = s->d1->next_state;
 406             break;
 407 #endif
 408
 409         case SSL3_ST_SW_SRVR_HELLO_A:
 410         case SSL3_ST_SW_SRVR_HELLO_B:
 411             s->renegotiate = 2;
 412             dtls1_start_timer(s);
 413             ret = ssl3_send_server_hello(s);
 414             if (ret <= 0)
 415                 goto end;
 416
 417             if (s->hit) {
 418 #ifndef OPENSSL_NO_SCTP
 419                 /*
 420                  * Add new shared key for SCTP-Auth, will be ignored if no
 421                  * SCTP used.
 422                  */
 423                 snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 424                          DTLS1_SCTP_AUTH_LABEL);
 425
 426                 if (SSL_export_keying_material(s, sctpauthkey,
 427                         sizeof(sctpauthkey), labelbuffer,
 428                         sizeof(labelbuffer), NULL, 0, 0) <= 0) {
 429                     ret = -1;
 430                     s->state = SSL_ST_ERR;
 431                     goto end;
 432                 }
 433
 434                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 435                          sizeof(sctpauthkey), sctpauthkey);
 436 #endif
 437 #ifndef OPENSSL_NO_TLSEXT
 438                 if (s->tlsext_ticket_expected)
 439                     s->state = SSL3_ST_SW_SESSION_TICKET_A;
 440                 else
 441                     s->state = SSL3_ST_SW_CHANGE_A;
 442 #else
 443                 s->state = SSL3_ST_SW_CHANGE_A;
 444 #endif
 445             } else
 446                 s->state = SSL3_ST_SW_CERT_A;
 447             s->init_num = 0;
 448             break;
 449
 450         case SSL3_ST_SW_CERT_A:
 451         case SSL3_ST_SW_CERT_B:
 452             /* Check if it is anon DH or normal PSK */
 453             if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
 454                 && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 455                 dtls1_start_timer(s);
 456                 ret = ssl3_send_server_certificate(s);
 457                 if (ret <= 0)
 458                     goto end;
 459 #ifndef OPENSSL_NO_TLSEXT
 460                 if (s->tlsext_status_expected)
 461                     s->state = SSL3_ST_SW_CERT_STATUS_A;
 462                 else
 463                     s->state = SSL3_ST_SW_KEY_EXCH_A;
 464             } else {
 465                 skip = 1;
 466                 s->state = SSL3_ST_SW_KEY_EXCH_A;
 467             }
 468 #else
 469             } else
 470                 skip = 1;
 471
 472             s->state = SSL3_ST_SW_KEY_EXCH_A;
 473 #endif
 474             s->init_num = 0;
 475             break;
 476
 477         case SSL3_ST_SW_KEY_EXCH_A:
 478         case SSL3_ST_SW_KEY_EXCH_B:
 479             alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 480
 481             /*
 482              * clear this, it may get reset by
 483              * send_server_key_exchange
 484              */
 485             s->s3->tmp.use_rsa_tmp = 0;
 486
 487             /*
 488              * only send if a DH key exchange or RSA but we have a sign only
 489              * certificate
 490              */
 491             if (0
 492                 /*
 493                  * PSK: send ServerKeyExchange if PSK identity hint if
 494                  * provided
 495                  */
 496 #ifndef OPENSSL_NO_PSK
 497                 || ((alg_k & SSL_kPSK) && s->ctx->psk_identity_hint)
 498 #endif
 499                 || (alg_k & SSL_kDHE)
 500                 || (alg_k & SSL_kEECDH)
 501                 || ((alg_k & SSL_kRSA)
 502                     && (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
 503                         || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
 504                             && EVP_PKEY_size(s->cert->pkeys
 505                                              [SSL_PKEY_RSA_ENC].privatekey) *
 506                             8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
 507                         )
 508                     )
 509                 )
 510                 ) {
 511                 dtls1_start_timer(s);
 512                 ret = ssl3_send_server_key_exchange(s);
 513                 if (ret <= 0)
 514                     goto end;
 515             } else
 516                 skip = 1;
 517
 518             s->state = SSL3_ST_SW_CERT_REQ_A;
 519             s->init_num = 0;
 520             break;
 521
 522         case SSL3_ST_SW_CERT_REQ_A:
 523         case SSL3_ST_SW_CERT_REQ_B:
 524             if (                /* don't request cert unless asked for it: */
 525                    !(s->verify_mode & SSL_VERIFY_PEER) ||
 526                    /*
 527                     * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
 528                     * during re-negotiation:
 529                     */
 530                    ((s->session->peer != NULL) &&
 531                     (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
 532                    /*
 533                     * never request cert in anonymous ciphersuites (see
 534                     * section "Certificate request" in SSL 3 drafts and in
 535                     * RFC 2246):
 536                     */
 537                    ((s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) &&
 538                     /*
 539                      * ... except when the application insists on
 540                      * verification (against the specs, but s3_clnt.c accepts
 541                      * this for SSL 3)
 542                      */
 543                     !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) ||
 544                    /*
 545                     * never request cert in Kerberos ciphersuites
 546                     */
 547                    (s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5)
 548                    /*
 549                     * With normal PSK Certificates and Certificate Requests
 550                     * are omitted
 551                     */
 552                    || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 553                 /* no cert request */
 554                 skip = 1;
 555                 s->s3->tmp.cert_request = 0;
 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             } else {
 564                 s->s3->tmp.cert_request = 1;
 565                 dtls1_start_timer(s);
 566                 ret = ssl3_send_certificate_request(s);
 567                 if (ret <= 0)
 568                     goto end;
 569 #ifndef NETSCAPE_HANG_BUG
 570                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 571 # ifndef OPENSSL_NO_SCTP
 572                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 573                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 574                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 575                 }
 576 # endif
 577 #else
 578                 s->state = SSL3_ST_SW_FLUSH;
 579                 s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
 580 # ifndef OPENSSL_NO_SCTP
 581                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 582                     s->d1->next_state = s->s3->tmp.next_state;
 583                     s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 584                 }
 585 # endif
 586 #endif
 587                 s->init_num = 0;
 588             }
 589             break;
 590
 591         case SSL3_ST_SW_SRVR_DONE_A:
 592         case SSL3_ST_SW_SRVR_DONE_B:
 593             dtls1_start_timer(s);
 594             ret = ssl3_send_server_done(s);
 595             if (ret <= 0)
 596                 goto end;
 597             s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
 598             s->state = SSL3_ST_SW_FLUSH;
 599             s->init_num = 0;
 600             break;
 601
 602         case SSL3_ST_SW_FLUSH:
 603             s->rwstate = SSL_WRITING;
 604             if (BIO_flush(s->wbio) <= 0) {
 605                 /*
 606                  * If the write error was fatal, stop trying
 607                  */
 608                 if (!BIO_should_retry(s->wbio)) {
 609                     s->rwstate = SSL_NOTHING;
 610                     s->state = s->s3->tmp.next_state;
 611                 }
 612
 613                 ret = -1;
 614                 goto end;
 615             }
 616             s->rwstate = SSL_NOTHING;
 617             s->state = s->s3->tmp.next_state;
 618             break;
 619
 620         case SSL3_ST_SR_CERT_A:
 621         case SSL3_ST_SR_CERT_B:
 622             if (s->s3->tmp.cert_request) {
 623                 ret = ssl3_get_client_certificate(s);
 624                 if (ret <= 0)
 625                     goto end;
 626             }
 627             s->init_num = 0;
 628             s->state = SSL3_ST_SR_KEY_EXCH_A;
 629             break;
 630
 631         case SSL3_ST_SR_KEY_EXCH_A:
 632         case SSL3_ST_SR_KEY_EXCH_B:
 633             ret = ssl3_get_client_key_exchange(s);
 634             if (ret <= 0)
 635                 goto end;
 636 #ifndef OPENSSL_NO_SCTP
 637             /*
 638              * Add new shared key for SCTP-Auth, will be ignored if no SCTP
 639              * used.
 640              */
 641             snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 642                      DTLS1_SCTP_AUTH_LABEL);
 643
 644             if (SSL_export_keying_material(s, sctpauthkey,
 645                                        sizeof(sctpauthkey), labelbuffer,
 646                                        sizeof(labelbuffer), NULL, 0, 0) <= 0) {
 647                 ret = -1;
 648                 s->state = SSL_ST_ERR;
 649                 goto end;
 650             }
 651
 652             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 653                      sizeof(sctpauthkey), sctpauthkey);
 654 #endif
 655
 656             s->state = SSL3_ST_SR_CERT_VRFY_A;
 657             s->init_num = 0;
 658
 659             if (ret == 2) {
 660                 /*
 661                  * For the ECDH ciphersuites when the client sends its ECDH
 662                  * pub key in a certificate, the CertificateVerify message is
 663                  * not sent.
 664                  */
 665                 s->state = SSL3_ST_SR_FINISHED_A;
 666                 s->init_num = 0;
 667             } else if (SSL_USE_SIGALGS(s)) {
 668                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 669                 s->init_num = 0;
 670                 if (!s->session->peer)
 671                     break;
 672                 /*
 673                  * For sigalgs freeze the handshake buffer at this point and
 674                  * digest cached records.
 675                  */
 676                 if (!s->s3->handshake_buffer) {
 677                     SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
 678                     s->state = SSL_ST_ERR;
 679                     return -1;
 680                 }
 681                 s->s3->flags |= TLS1_FLAGS_KEEP_HANDSHAKE;
 682                 if (!ssl3_digest_cached_records(s)) {
 683                     s->state = SSL_ST_ERR;
 684                     return -1;
 685                 }
 686             } else {
 687                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 688                 s->init_num = 0;
 689
 690                 /*
 691                  * We need to get hashes here so if there is a client cert,
 692                  * it can be verified
 693                  */
 694                 s->method->ssl3_enc->cert_verify_mac(s,
 695                                                      NID_md5,
 696                                                      &(s->s3->
 697                                                        tmp.cert_verify_md
 698                                                        [0]));
 699                 s->method->ssl3_enc->cert_verify_mac(s, NID_sha1,
 700                                                      &(s->s3->
 701                                                        tmp.cert_verify_md
 702                                                        [MD5_DIGEST_LENGTH]));
 703             }
 704             break;
 705
 706         case SSL3_ST_SR_CERT_VRFY_A:
 707         case SSL3_ST_SR_CERT_VRFY_B:
 708             ret = ssl3_get_cert_verify(s);
 709             if (ret <= 0)
 710                 goto end;
 711 #ifndef OPENSSL_NO_SCTP
 712             if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
 713                 state == SSL_ST_RENEGOTIATE)
 714                 s->state = DTLS1_SCTP_ST_SR_READ_SOCK;
 715             else
 716 #endif
 717                 s->state = SSL3_ST_SR_FINISHED_A;
 718             s->init_num = 0;
 719             break;
 720
 721         case SSL3_ST_SR_FINISHED_A:
 722         case SSL3_ST_SR_FINISHED_B:
 723             /*
 724              * Enable CCS. Receiving a CCS clears the flag, so make
 725              * sure not to re-enable it to ban duplicates. This *should* be the
 726              * first time we have received one - but we check anyway to be
 727              * cautious.
 728              * s->s3->change_cipher_spec is set when a CCS is
 729              * processed in d1_pkt.c, and remains set until
 730              * the client's Finished message is read.
 731              */
 732             if (!s->s3->change_cipher_spec)
 733                 s->d1->change_cipher_spec_ok = 1;
 734             ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
 735                                     SSL3_ST_SR_FINISHED_B);
 736             if (ret <= 0)
 737                 goto end;
 738             dtls1_stop_timer(s);
 739             if (s->hit)
 740                 s->state = SSL_ST_OK;
 741 #ifndef OPENSSL_NO_TLSEXT
 742             else if (s->tlsext_ticket_expected)
 743                 s->state = SSL3_ST_SW_SESSION_TICKET_A;
 744 #endif
 745             else
 746                 s->state = SSL3_ST_SW_CHANGE_A;
 747             s->init_num = 0;
 748             break;
 749
 750 #ifndef OPENSSL_NO_TLSEXT
 751         case SSL3_ST_SW_SESSION_TICKET_A:
 752         case SSL3_ST_SW_SESSION_TICKET_B:
 753             ret = ssl3_send_newsession_ticket(s);
 754             if (ret <= 0)
 755                 goto end;
 756             s->state = SSL3_ST_SW_CHANGE_A;
 757             s->init_num = 0;
 758             break;
 759
 760         case SSL3_ST_SW_CERT_STATUS_A:
 761         case SSL3_ST_SW_CERT_STATUS_B:
 762             ret = ssl3_send_cert_status(s);
 763             if (ret <= 0)
 764                 goto end;
 765             s->state = SSL3_ST_SW_KEY_EXCH_A;
 766             s->init_num = 0;
 767             break;
 768
 769 #endif
 770
 771         case SSL3_ST_SW_CHANGE_A:
 772         case SSL3_ST_SW_CHANGE_B:
 773
 774             s->session->cipher = s->s3->tmp.new_cipher;
 775             if (!s->method->ssl3_enc->setup_key_block(s)) {
 776                 ret = -1;
 777                 s->state = SSL_ST_ERR;
 778                 goto end;
 779             }
 780
 781             ret = dtls1_send_change_cipher_spec(s,
 782                                                 SSL3_ST_SW_CHANGE_A,
 783                                                 SSL3_ST_SW_CHANGE_B);
 784
 785             if (ret <= 0)
 786                 goto end;
 787
 788 #ifndef OPENSSL_NO_SCTP
 789             if (!s->hit) {
 790                 /*
 791                  * Change to new shared key of SCTP-Auth, will be ignored if
 792                  * no SCTP used.
 793                  */
 794                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 795                          0, NULL);
 796             }
 797 #endif
 798
 799             s->state = SSL3_ST_SW_FINISHED_A;
 800             s->init_num = 0;
 801
 802             if (!s->method->ssl3_enc->change_cipher_state(s,
 803                                                           SSL3_CHANGE_CIPHER_SERVER_WRITE))
 804             {
 805                 ret = -1;
 806                 s->state = SSL_ST_ERR;
 807                 goto end;
 808             }
 809
 810             dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
 811             break;
 812
 813         case SSL3_ST_SW_FINISHED_A:
 814         case SSL3_ST_SW_FINISHED_B:
 815             ret = ssl3_send_finished(s,
 816                                      SSL3_ST_SW_FINISHED_A,
 817                                      SSL3_ST_SW_FINISHED_B,
 818                                      s->method->
 819                                      ssl3_enc->server_finished_label,
 820                                      s->method->
 821                                      ssl3_enc->server_finished_label_len);
 822             if (ret <= 0)
 823                 goto end;
 824             s->state = SSL3_ST_SW_FLUSH;
 825             if (s->hit) {
 826                 s->s3->tmp.next_state = SSL3_ST_SR_FINISHED_A;
 827
 828 #ifndef OPENSSL_NO_SCTP
 829                 /*
 830                  * Change to new shared key of SCTP-Auth, will be ignored if
 831                  * no SCTP used.
 832                  */
 833                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 834                          0, NULL);
 835 #endif
 836             } else {
 837                 s->s3->tmp.next_state = SSL_ST_OK;
 838 #ifndef OPENSSL_NO_SCTP
 839                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 840                     s->d1->next_state = s->s3->tmp.next_state;
 841                     s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 842                 }
 843 #endif
 844             }
 845             s->init_num = 0;
 846             break;
 847
 848         case SSL_ST_OK:
 849             /* clean a few things up */
 850             ssl3_cleanup_key_block(s);
 851
 852 #if 0
 853             BUF_MEM_free(s->init_buf);
 854             s->init_buf = NULL;
 855 #endif
 856
 857             /* remove buffering on output */
 858             ssl_free_wbio_buffer(s);
 859
 860             s->init_num = 0;
 861
 862             if (s->renegotiate == 2) { /* skipped if we just sent a
 863                                         * HelloRequest */
 864                 s->renegotiate = 0;
 865                 s->new_session = 0;
 866
 867                 ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
 868
 869                 s->ctx->stats.sess_accept_good++;
 870                 /* s->server=1; */
 871                 s->handshake_func = dtls1_accept;
 872
 873                 if (cb != NULL)
 874                     cb(s, SSL_CB_HANDSHAKE_DONE, 1);
 875             }
 876
 877             ret = 1;
 878
 879             /* done handshaking, next message is client hello */
 880             s->d1->handshake_read_seq = 0;
 881             /* next message is server hello */
 882             s->d1->handshake_write_seq = 0;
 883             s->d1->next_handshake_write_seq = 0;
 884             goto end;
 885             /* break; */
 886
 887         case SSL_ST_ERR:
 888         default:
 889             SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
 890             ret = -1;
 891             goto end;
 892             /* break; */
 893         }
 894
 895         if (!s->s3->tmp.reuse_message && !skip) {
 896             if (s->debug) {
 897                 if ((ret = BIO_flush(s->wbio)) <= 0)
 898                     goto end;
 899             }
 900
 901             if ((cb != NULL) && (s->state != state)) {
 902                 new_state = s->state;
 903                 s->state = state;
 904                 cb(s, SSL_CB_ACCEPT_LOOP, 1);
 905                 s->state = new_state;
 906             }
 907         }
 908         skip = 0;
 909     }
 910  end:
 911     /* BIO_flush(s->wbio); */
 912
 913     s->in_handshake--;
 914 #ifndef OPENSSL_NO_SCTP
 915     /*
 916      * Notify SCTP BIO socket to leave handshake mode and prevent stream
 917      * identifier other than 0. Will be ignored if no SCTP is used.
 918      */
 919     BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
 920              s->in_handshake, NULL);
 921 #endif
 922
 923     if (cb != NULL)
 924         cb(s, SSL_CB_ACCEPT_EXIT, ret);
 925     return (ret);
 926 }
 927
 928 int dtls1_send_hello_verify_request(SSL *s)
 929 {
 930     unsigned int msg_len;
 931     unsigned char *msg, *buf, *p;
 932
 933     if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
 934         buf = (unsigned char *)s->init_buf->data;
 935
 936         msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
 937         /* Always use DTLS 1.0 version: see RFC 6347 */
 938         *(p++) = DTLS1_VERSION >> 8;
 939         *(p++) = DTLS1_VERSION & 0xFF;
 940
 941         if (s->ctx->app_gen_cookie_cb == NULL ||
 942             s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
 943                                       &(s->d1->cookie_len)) == 0) {
 944             SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
 945                    ERR_R_INTERNAL_ERROR);
 946             s->state = SSL_ST_ERR;
 947             return 0;
 948         }
 949
 950         *(p++) = (unsigned char)s->d1->cookie_len;
 951         memcpy(p, s->d1->cookie, s->d1->cookie_len);
 952         p += s->d1->cookie_len;
 953         msg_len = p - msg;
 954
 955         dtls1_set_message_header(s, buf,
 956                                  DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0,
 957                                  msg_len);
 958
 959         s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
 960         /* number of bytes to write */
 961         s->init_num = p - buf;
 962         s->init_off = 0;
 963     }
 964
 965     /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
 966     return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
 967 }