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             /*
 261              * Should have been reset by ssl3_get_finished, too.
 262              */
 263             s->s3->change_cipher_spec = 0;
 264
 265             if (s->state != SSL_ST_RENEGOTIATE) {
 266                 /*
 267                  * Ok, we now need to push on a buffering BIO so that the
 268                  * output is sent in a way that TCP likes :-) ...but not with
 269                  * SCTP :-)
 270                  */
 271 #ifndef OPENSSL_NO_SCTP
 272                 if (!BIO_dgram_is_sctp(SSL_get_wbio(s)))
 273 #endif
 274                     if (!ssl_init_wbio_buffer(s, 1)) {
 275                         ret = -1;
 276                         s->state = SSL_ST_ERR;
 277                         goto end;
 278                     }
 279
 280                 ssl3_init_finished_mac(s);
 281                 s->state = SSL3_ST_SR_CLNT_HELLO_A;
 282                 s->ctx->stats.sess_accept++;
 283             } else {
 284                 /*
 285                  * s->state == SSL_ST_RENEGOTIATE, we will just send a
 286                  * HelloRequest
 287                  */
 288                 s->ctx->stats.sess_accept_renegotiate++;
 289                 s->state = SSL3_ST_SW_HELLO_REQ_A;
 290             }
 291
 292             break;
 293
 294         case SSL3_ST_SW_HELLO_REQ_A:
 295         case SSL3_ST_SW_HELLO_REQ_B:
 296
 297             s->shutdown = 0;
 298             dtls1_clear_record_buffer(s);
 299             dtls1_start_timer(s);
 300             ret = ssl3_send_hello_request(s);
 301             if (ret <= 0)
 302                 goto end;
 303             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 304             s->state = SSL3_ST_SW_FLUSH;
 305             s->init_num = 0;
 306
 307             ssl3_init_finished_mac(s);
 308             break;
 309
 310         case SSL3_ST_SW_HELLO_REQ_C:
 311             s->state = SSL_ST_OK;
 312             break;
 313
 314         case SSL3_ST_SR_CLNT_HELLO_A:
 315         case SSL3_ST_SR_CLNT_HELLO_B:
 316         case SSL3_ST_SR_CLNT_HELLO_C:
 317
 318             s->shutdown = 0;
 319             ret = ssl3_get_client_hello(s);
 320             if (ret <= 0)
 321                 goto end;
 322             dtls1_stop_timer(s);
 323
 324             if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
 325                 s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
 326             else
 327                 s->state = SSL3_ST_SW_SRVR_HELLO_A;
 328
 329             s->init_num = 0;
 330
 331             /*
 332              * Reflect ClientHello sequence to remain stateless while
 333              * listening
 334              */
 335             if (listen) {
 336                 DTLS_RECORD_LAYER_resync_write(&s->rlayer);
 337             }
 338
 339             /* If we're just listening, stop here */
 340             if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
 341                 ret = 2;
 342                 s->d1->listen = 0;
 343                 /*
 344                  * Set expected sequence numbers to continue the handshake.
 345                  */
 346                 s->d1->handshake_read_seq = 2;
 347                 s->d1->handshake_write_seq = 1;
 348                 s->d1->next_handshake_write_seq = 1;
 349                 goto end;
 350             }
 351
 352             break;
 353
 354         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
 355         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
 356
 357             ret = dtls1_send_hello_verify_request(s);
 358             if (ret <= 0)
 359                 goto end;
 360             s->state = SSL3_ST_SW_FLUSH;
 361             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 362
 363             /* HelloVerifyRequest resets Finished MAC */
 364             if (s->version != DTLS1_BAD_VER)
 365                 ssl3_init_finished_mac(s);
 366             break;
 367
 368 #ifndef OPENSSL_NO_SCTP
 369         case DTLS1_SCTP_ST_SR_READ_SOCK:
 370
 371             if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
 372                 s->s3->in_read_app_data = 2;
 373                 s->rwstate = SSL_READING;
 374                 BIO_clear_retry_flags(SSL_get_rbio(s));
 375                 BIO_set_retry_read(SSL_get_rbio(s));
 376                 ret = -1;
 377                 goto end;
 378             }
 379
 380             s->state = SSL3_ST_SR_CHANGE_A;
 381             break;
 382
 383         case DTLS1_SCTP_ST_SW_WRITE_SOCK:
 384             ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
 385             if (ret < 0)
 386                 goto end;
 387
 388             if (ret == 0) {
 389                 if (s->d1->next_state != SSL_ST_OK) {
 390                     s->s3->in_read_app_data = 2;
 391                     s->rwstate = SSL_READING;
 392                     BIO_clear_retry_flags(SSL_get_rbio(s));
 393                     BIO_set_retry_read(SSL_get_rbio(s));
 394                     ret = -1;
 395                     goto end;
 396                 }
 397             }
 398
 399             s->state = s->d1->next_state;
 400             break;
 401 #endif
 402
 403         case SSL3_ST_SW_SRVR_HELLO_A:
 404         case SSL3_ST_SW_SRVR_HELLO_B:
 405             s->renegotiate = 2;
 406             dtls1_start_timer(s);
 407             ret = ssl3_send_server_hello(s);
 408             if (ret <= 0)
 409                 goto end;
 410
 411             if (s->hit) {
 412 #ifndef OPENSSL_NO_SCTP
 413                 /*
 414                  * Add new shared key for SCTP-Auth, will be ignored if no
 415                  * SCTP used.
 416                  */
 417                 snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 418                          DTLS1_SCTP_AUTH_LABEL);
 419
 420                 SSL_export_keying_material(s, sctpauthkey,
 421                                            sizeof(sctpauthkey), labelbuffer,
 422                                            sizeof(labelbuffer), NULL, 0, 0);
 423
 424                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 425                          sizeof(sctpauthkey), sctpauthkey);
 426 #endif
 427                 if (s->tlsext_ticket_expected)
 428                     s->state = SSL3_ST_SW_SESSION_TICKET_A;
 429                 else
 430                     s->state = SSL3_ST_SW_CHANGE_A;
 431             } else
 432                 s->state = SSL3_ST_SW_CERT_A;
 433             s->init_num = 0;
 434             break;
 435
 436         case SSL3_ST_SW_CERT_A:
 437         case SSL3_ST_SW_CERT_B:
 438             /* Check if it is anon DH or normal PSK */
 439             if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
 440                 && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 441                 dtls1_start_timer(s);
 442                 ret = ssl3_send_server_certificate(s);
 443                 if (ret <= 0)
 444                     goto end;
 445
 446                 if (s->tlsext_status_expected)
 447                     s->state = SSL3_ST_SW_CERT_STATUS_A;
 448                 else
 449                     s->state = SSL3_ST_SW_KEY_EXCH_A;
 450             } else {
 451                 skip = 1;
 452                 s->state = SSL3_ST_SW_KEY_EXCH_A;
 453             }
 454             s->init_num = 0;
 455             break;
 456
 457         case SSL3_ST_SW_KEY_EXCH_A:
 458         case SSL3_ST_SW_KEY_EXCH_B:
 459             alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 460
 461             /*
 462              * clear this, it may get reset by
 463              * send_server_key_exchange
 464              */
 465             s->s3->tmp.use_rsa_tmp = 0;
 466
 467             /*
 468              * only send if a DH key exchange or RSA but we have a sign only
 469              * certificate
 470              */
 471             if (0
 472                 /*
 473                  * PSK: send ServerKeyExchange if PSK identity hint if
 474                  * provided
 475                  */
 476 #ifndef OPENSSL_NO_PSK
 477                 || ((alg_k & SSL_kPSK) && s->ctx->psk_identity_hint)
 478 #endif
 479                 || (alg_k & SSL_kDHE)
 480                 || (alg_k & SSL_kECDHE)
 481                 || ((alg_k & SSL_kRSA)
 482                     && (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
 483                         || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
 484                             && EVP_PKEY_size(s->cert->pkeys
 485                                              [SSL_PKEY_RSA_ENC].privatekey) *
 486                             8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
 487                         )
 488                     )
 489                 )
 490                 ) {
 491                 dtls1_start_timer(s);
 492                 ret = ssl3_send_server_key_exchange(s);
 493                 if (ret <= 0)
 494                     goto end;
 495             } else
 496                 skip = 1;
 497
 498             s->state = SSL3_ST_SW_CERT_REQ_A;
 499             s->init_num = 0;
 500             break;
 501
 502         case SSL3_ST_SW_CERT_REQ_A:
 503         case SSL3_ST_SW_CERT_REQ_B:
 504             if (                /* don't request cert unless asked for it: */
 505                    !(s->verify_mode & SSL_VERIFY_PEER) ||
 506                    /*
 507                     * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
 508                     * during re-negotiation:
 509                     */
 510                    ((s->session->peer != NULL) &&
 511                     (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
 512                    /*
 513                     * never request cert in anonymous ciphersuites (see
 514                     * section "Certificate request" in SSL 3 drafts and in
 515                     * RFC 2246):
 516                     */
 517                    ((s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) &&
 518                    /*
 519                     * ... except when the application insists on
 520                     * verification (against the specs, but s3_clnt.c accepts
 521                     * this for SSL 3)
 522                     */
 523                    !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
 524                    /*
 525                     * With normal PSK Certificates and Certificate Requests
 526                     * are omitted
 527                     */
 528                    || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 529                 /* no cert request */
 530                 skip = 1;
 531                 s->s3->tmp.cert_request = 0;
 532                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 533 #ifndef OPENSSL_NO_SCTP
 534                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 535                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 536                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 537                 }
 538 #endif
 539             } else {
 540                 s->s3->tmp.cert_request = 1;
 541                 dtls1_start_timer(s);
 542                 ret = ssl3_send_certificate_request(s);
 543                 if (ret <= 0)
 544                     goto end;
 545                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 546 # ifndef OPENSSL_NO_SCTP
 547                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 548                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 549                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 550                 }
 551 # endif
 552                 s->init_num = 0;
 553             }
 554             break;
 555
 556         case SSL3_ST_SW_SRVR_DONE_A:
 557         case SSL3_ST_SW_SRVR_DONE_B:
 558             dtls1_start_timer(s);
 559             ret = ssl3_send_server_done(s);
 560             if (ret <= 0)
 561                 goto end;
 562             s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
 563             s->state = SSL3_ST_SW_FLUSH;
 564             s->init_num = 0;
 565             break;
 566
 567         case SSL3_ST_SW_FLUSH:
 568             s->rwstate = SSL_WRITING;
 569             if (BIO_flush(s->wbio) <= 0) {
 570                 /*
 571                  * If the write error was fatal, stop trying
 572                  */
 573                 if (!BIO_should_retry(s->wbio)) {
 574                     s->rwstate = SSL_NOTHING;
 575                     s->state = s->s3->tmp.next_state;
 576                 }
 577
 578                 ret = -1;
 579                 goto end;
 580             }
 581             s->rwstate = SSL_NOTHING;
 582             s->state = s->s3->tmp.next_state;
 583             break;
 584
 585         case SSL3_ST_SR_CERT_A:
 586         case SSL3_ST_SR_CERT_B:
 587             if (s->s3->tmp.cert_request) {
 588                 ret = ssl3_get_client_certificate(s);
 589                 if (ret <= 0)
 590                     goto end;
 591             }
 592             s->init_num = 0;
 593             s->state = SSL3_ST_SR_KEY_EXCH_A;
 594             break;
 595
 596         case SSL3_ST_SR_KEY_EXCH_A:
 597         case SSL3_ST_SR_KEY_EXCH_B:
 598             ret = ssl3_get_client_key_exchange(s);
 599             if (ret <= 0)
 600                 goto end;
 601 #ifndef OPENSSL_NO_SCTP
 602             /*
 603              * Add new shared key for SCTP-Auth, will be ignored if no SCTP
 604              * used.
 605              */
 606             snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 607                      DTLS1_SCTP_AUTH_LABEL);
 608
 609             SSL_export_keying_material(s, sctpauthkey,
 610                                        sizeof(sctpauthkey), labelbuffer,
 611                                        sizeof(labelbuffer), NULL, 0, 0);
 612
 613             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 614                      sizeof(sctpauthkey), sctpauthkey);
 615 #endif
 616
 617             s->state = SSL3_ST_SR_CERT_VRFY_A;
 618             s->init_num = 0;
 619
 620             if (ret == 2) {
 621                 /*
 622                  * For the ECDH ciphersuites when the client sends its ECDH
 623                  * pub key in a certificate, the CertificateVerify message is
 624                  * not sent.
 625                  */
 626                 s->state = SSL3_ST_SR_CHANGE_A;
 627                 s->init_num = 0;
 628             } else if (SSL_USE_SIGALGS(s)) {
 629                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 630                 s->init_num = 0;
 631                 if (!s->session->peer)
 632                     break;
 633                 if (!s->s3->handshake_buffer) {
 634                     SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
 635                     s->state = SSL_ST_ERR;
 636                     return -1;
 637                 }
 638                 /*
 639                  * For sigalgs freeze the handshake buffer. If we support
 640                  * extms we've done this already.
 641                  */
 642                 if (!ssl3_digest_cached_records(s, 1)) {
 643                     s->state = SSL_ST_ERR;
 644                     return -1;
 645                 }
 646             } else {
 647                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 648                 s->init_num = 0;
 649
 650                 /*
 651                  * We need to get hashes here so if there is a client cert,
 652                  * it can be verified
 653                  */
 654                 s->method->ssl3_enc->cert_verify_mac(s,
 655                                                      NID_md5,
 656                                                      &(s->s3->
 657                                                        tmp.cert_verify_md
 658                                                        [0]));
 659                 s->method->ssl3_enc->cert_verify_mac(s, NID_sha1,
 660                                                      &(s->s3->
 661                                                        tmp.cert_verify_md
 662                                                        [MD5_DIGEST_LENGTH]));
 663             }
 664             break;
 665
 666         case SSL3_ST_SR_CERT_VRFY_A:
 667         case SSL3_ST_SR_CERT_VRFY_B:
 668             ret = ssl3_get_cert_verify(s);
 669             if (ret <= 0)
 670                 goto end;
 671 #ifndef OPENSSL_NO_SCTP
 672             if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
 673                 state == SSL_ST_RENEGOTIATE)
 674                 s->state = DTLS1_SCTP_ST_SR_READ_SOCK;
 675             else
 676 #endif
 677                 s->state = SSL3_ST_SR_CHANGE_A;
 678             s->init_num = 0;
 679             break;
 680
 681         case SSL3_ST_SR_CHANGE_A:
 682         case SSL3_ST_SR_CHANGE_B:
 683             ret = ssl3_get_change_cipher_spec(s, SSL3_ST_SR_CHANGE_A,
 684                                               SSL3_ST_SR_CHANGE_B);
 685             if (ret <= 0)
 686                 goto end;
 687
 688             s->state = SSL3_ST_SR_FINISHED_A;
 689             s->init_num = 0;
 690             break;
 691
 692         case SSL3_ST_SR_FINISHED_A:
 693         case SSL3_ST_SR_FINISHED_B:
 694             ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
 695                                     SSL3_ST_SR_FINISHED_B);
 696             if (ret <= 0)
 697                 goto end;
 698             dtls1_stop_timer(s);
 699             if (s->hit)
 700                 s->state = SSL_ST_OK;
 701             else if (s->tlsext_ticket_expected)
 702                 s->state = SSL3_ST_SW_SESSION_TICKET_A;
 703             else
 704                 s->state = SSL3_ST_SW_CHANGE_A;
 705             s->init_num = 0;
 706             break;
 707
 708         case SSL3_ST_SW_SESSION_TICKET_A:
 709         case SSL3_ST_SW_SESSION_TICKET_B:
 710             ret = ssl3_send_newsession_ticket(s);
 711             if (ret <= 0)
 712                 goto end;
 713             s->state = SSL3_ST_SW_CHANGE_A;
 714             s->init_num = 0;
 715             break;
 716
 717         case SSL3_ST_SW_CERT_STATUS_A:
 718         case SSL3_ST_SW_CERT_STATUS_B:
 719             ret = ssl3_send_cert_status(s);
 720             if (ret <= 0)
 721                 goto end;
 722             s->state = SSL3_ST_SW_KEY_EXCH_A;
 723             s->init_num = 0;
 724             break;
 725
 726         case SSL3_ST_SW_CHANGE_A:
 727         case SSL3_ST_SW_CHANGE_B:
 728
 729             s->session->cipher = s->s3->tmp.new_cipher;
 730             if (!s->method->ssl3_enc->setup_key_block(s)) {
 731                 ret = -1;
 732                 s->state = SSL_ST_ERR;
 733                 goto end;
 734             }
 735
 736             ret = dtls1_send_change_cipher_spec(s,
 737                                                 SSL3_ST_SW_CHANGE_A,
 738                                                 SSL3_ST_SW_CHANGE_B);
 739
 740             if (ret <= 0)
 741                 goto end;
 742
 743 #ifndef OPENSSL_NO_SCTP
 744             if (!s->hit) {
 745                 /*
 746                  * Change to new shared key of SCTP-Auth, will be ignored if
 747                  * no SCTP used.
 748                  */
 749                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 750                          0, NULL);
 751             }
 752 #endif
 753
 754             s->state = SSL3_ST_SW_FINISHED_A;
 755             s->init_num = 0;
 756
 757             if (!s->method->ssl3_enc->change_cipher_state(s,
 758                                                           SSL3_CHANGE_CIPHER_SERVER_WRITE))
 759             {
 760                 ret = -1;
 761                 s->state = SSL_ST_ERR;
 762                 goto end;
 763             }
 764
 765             dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
 766             break;
 767
 768         case SSL3_ST_SW_FINISHED_A:
 769         case SSL3_ST_SW_FINISHED_B:
 770             ret = ssl3_send_finished(s,
 771                                      SSL3_ST_SW_FINISHED_A,
 772                                      SSL3_ST_SW_FINISHED_B,
 773                                      s->method->
 774                                      ssl3_enc->server_finished_label,
 775                                      s->method->
 776                                      ssl3_enc->server_finished_label_len);
 777             if (ret <= 0)
 778                 goto end;
 779             s->state = SSL3_ST_SW_FLUSH;
 780             if (s->hit) {
 781                 s->s3->tmp.next_state = SSL3_ST_SR_CHANGE_A;
 782
 783 #ifndef OPENSSL_NO_SCTP
 784                 /*
 785                  * Change to new shared key of SCTP-Auth, will be ignored if
 786                  * no SCTP used.
 787                  */
 788                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 789                          0, NULL);
 790 #endif
 791             } else {
 792                 s->s3->tmp.next_state = SSL_ST_OK;
 793 #ifndef OPENSSL_NO_SCTP
 794                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 795                     s->d1->next_state = s->s3->tmp.next_state;
 796                     s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 797                 }
 798 #endif
 799             }
 800             s->init_num = 0;
 801             break;
 802
 803         case SSL_ST_OK:
 804             /* clean a few things up */
 805             ssl3_cleanup_key_block(s);
 806
 807             /* remove buffering on output */
 808             ssl_free_wbio_buffer(s);
 809
 810             s->init_num = 0;
 811
 812             if (s->renegotiate == 2) { /* skipped if we just sent a
 813                                         * HelloRequest */
 814                 s->renegotiate = 0;
 815                 s->new_session = 0;
 816
 817                 ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
 818
 819                 s->ctx->stats.sess_accept_good++;
 820                 /* s->server=1; */
 821                 s->handshake_func = dtls1_accept;
 822
 823                 if (cb != NULL)
 824                     cb(s, SSL_CB_HANDSHAKE_DONE, 1);
 825             }
 826
 827             ret = 1;
 828
 829             /* done handshaking, next message is client hello */
 830             s->d1->handshake_read_seq = 0;
 831             /* next message is server hello */
 832             s->d1->handshake_write_seq = 0;
 833             s->d1->next_handshake_write_seq = 0;
 834             goto end;
 835             /* break; */
 836
 837         case SSL_ST_ERR:
 838         default:
 839             SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
 840             ret = -1;
 841             goto end;
 842             /* break; */
 843         }
 844
 845         if (!s->s3->tmp.reuse_message && !skip) {
 846             if (s->debug) {
 847                 if ((ret = BIO_flush(s->wbio)) <= 0)
 848                     goto end;
 849             }
 850
 851             if ((cb != NULL) && (s->state != state)) {
 852                 new_state = s->state;
 853                 s->state = state;
 854                 cb(s, SSL_CB_ACCEPT_LOOP, 1);
 855                 s->state = new_state;
 856             }
 857         }
 858         skip = 0;
 859     }
 860  end:
 861     /* BIO_flush(s->wbio); */
 862
 863     s->in_handshake--;
 864 #ifndef OPENSSL_NO_SCTP
 865     /*
 866      * Notify SCTP BIO socket to leave handshake mode and prevent stream
 867      * identifier other than 0. Will be ignored if no SCTP is used.
 868      */
 869     BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
 870              s->in_handshake, NULL);
 871 #endif
 872
 873     if (cb != NULL)
 874         cb(s, SSL_CB_ACCEPT_EXIT, ret);
 875     return (ret);
 876 }
 877
 878 int dtls1_send_hello_verify_request(SSL *s)
 879 {
 880     unsigned int msg_len;
 881     unsigned char *msg, *buf, *p;
 882
 883     if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
 884         buf = (unsigned char *)s->init_buf->data;
 885
 886         msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
 887         /* Always use DTLS 1.0 version: see RFC 6347 */
 888         *(p++) = DTLS1_VERSION >> 8;
 889         *(p++) = DTLS1_VERSION & 0xFF;
 890
 891         if (s->ctx->app_gen_cookie_cb == NULL ||
 892             s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
 893                                       &(s->d1->cookie_len)) == 0) {
 894             SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
 895                    ERR_R_INTERNAL_ERROR);
 896             s->state = SSL_ST_ERR;
 897             return 0;
 898         }
 899
 900         *(p++) = (unsigned char)s->d1->cookie_len;
 901         memcpy(p, s->d1->cookie, s->d1->cookie_len);
 902         p += s->d1->cookie_len;
 903         msg_len = p - msg;
 904
 905         dtls1_set_message_header(s, buf,
 906                                  DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0,
 907                                  msg_len);
 908
 909         s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
 910         /* number of bytes to write */
 911         s->init_num = p - buf;
 912         s->init_off = 0;
 913     }
 914
 915     /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
 916     return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
 917 }