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                 if (!ssl3_init_finished_mac(s)) {
 286                     ret = -1;
 287                     s->state = SSL_ST_ERR;
 288                     goto end;
 289                 }
 290
 291                 s->state = SSL3_ST_SR_CLNT_HELLO_A;
 292                 s->ctx->stats.sess_accept++;
 293             } else if (!s->s3->send_connection_binding &&
 294                        !(s->options &
 295                          SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) {
 296                 /*
 297                  * Server attempting to renegotiate with client that doesn't
 298                  * support secure renegotiation.
 299                  */
 300                 SSLerr(SSL_F_DTLS1_ACCEPT,
 301                        SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
 302                 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
 303                 ret = -1;
 304                 s->state = SSL_ST_ERR;
 305                 goto end;
 306             } else {
 307                 /*
 308                  * s->state == SSL_ST_RENEGOTIATE, we will just send a
 309                  * HelloRequest
 310                  */
 311                 s->ctx->stats.sess_accept_renegotiate++;
 312                 s->state = SSL3_ST_SW_HELLO_REQ_A;
 313             }
 314
 315             break;
 316
 317         case SSL3_ST_SW_HELLO_REQ_A:
 318         case SSL3_ST_SW_HELLO_REQ_B:
 319
 320             s->shutdown = 0;
 321             dtls1_clear_sent_buffer(s);
 322             dtls1_start_timer(s);
 323             ret = ssl3_send_hello_request(s);
 324             if (ret <= 0)
 325                 goto end;
 326             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 327             s->state = SSL3_ST_SW_FLUSH;
 328             s->init_num = 0;
 329
 330             if (!ssl3_init_finished_mac(s)) {
 331                 ret = -1;
 332                 s->state = SSL_ST_ERR;
 333                 goto end;
 334             }
 335             break;
 336
 337         case SSL3_ST_SW_HELLO_REQ_C:
 338             s->state = SSL_ST_OK;
 339             break;
 340
 341         case SSL3_ST_SR_CLNT_HELLO_A:
 342         case SSL3_ST_SR_CLNT_HELLO_B:
 343         case SSL3_ST_SR_CLNT_HELLO_C:
 344
 345             s->shutdown = 0;
 346             ret = ssl3_get_client_hello(s);
 347             if (ret <= 0)
 348                 goto end;
 349             dtls1_stop_timer(s);
 350
 351             if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
 352                 s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
 353             else
 354                 s->state = SSL3_ST_SW_SRVR_HELLO_A;
 355
 356             s->init_num = 0;
 357
 358             /* If we're just listening, stop here */
 359             if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
 360                 ret = 2;
 361                 s->d1->listen = 0;
 362                 /*
 363                  * Set expected sequence numbers to continue the handshake.
 364                  */
 365                 s->d1->handshake_read_seq = 2;
 366                 s->d1->handshake_write_seq = 1;
 367                 s->d1->next_handshake_write_seq = 1;
 368                 goto end;
 369             }
 370
 371             break;
 372
 373         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
 374         case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
 375
 376             ret = dtls1_send_hello_verify_request(s);
 377             if (ret <= 0)
 378                 goto end;
 379             s->state = SSL3_ST_SW_FLUSH;
 380             s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 381
 382             /* HelloVerifyRequest resets Finished MAC */
 383             if (s->version != DTLS1_BAD_VER)
 384                 if (!ssl3_init_finished_mac(s)) {
 385                     ret = -1;
 386                     s->state = SSL_ST_ERR;
 387                     goto end;
 388                 }
 389             break;
 390
 391 #ifndef OPENSSL_NO_SCTP
 392         case DTLS1_SCTP_ST_SR_READ_SOCK:
 393
 394             if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
 395                 s->s3->in_read_app_data = 2;
 396                 s->rwstate = SSL_READING;
 397                 BIO_clear_retry_flags(SSL_get_rbio(s));
 398                 BIO_set_retry_read(SSL_get_rbio(s));
 399                 ret = -1;
 400                 goto end;
 401             }
 402
 403             s->state = SSL3_ST_SR_FINISHED_A;
 404             break;
 405
 406         case DTLS1_SCTP_ST_SW_WRITE_SOCK:
 407             ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
 408             if (ret < 0)
 409                 goto end;
 410
 411             if (ret == 0) {
 412                 if (s->d1->next_state != SSL_ST_OK) {
 413                     s->s3->in_read_app_data = 2;
 414                     s->rwstate = SSL_READING;
 415                     BIO_clear_retry_flags(SSL_get_rbio(s));
 416                     BIO_set_retry_read(SSL_get_rbio(s));
 417                     ret = -1;
 418                     goto end;
 419                 }
 420             }
 421
 422             s->state = s->d1->next_state;
 423             break;
 424 #endif
 425
 426         case SSL3_ST_SW_SRVR_HELLO_A:
 427         case SSL3_ST_SW_SRVR_HELLO_B:
 428             s->renegotiate = 2;
 429             dtls1_start_timer(s);
 430             ret = ssl3_send_server_hello(s);
 431             if (ret <= 0)
 432                 goto end;
 433
 434             if (s->hit) {
 435 #ifndef OPENSSL_NO_SCTP
 436                 /*
 437                  * Add new shared key for SCTP-Auth, will be ignored if no
 438                  * SCTP used.
 439                  */
 440                 snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 441                          DTLS1_SCTP_AUTH_LABEL);
 442
 443                 if (SSL_export_keying_material(s, sctpauthkey,
 444                         sizeof(sctpauthkey), labelbuffer,
 445                         sizeof(labelbuffer), NULL, 0, 0) <= 0) {
 446                     ret = -1;
 447                     s->state = SSL_ST_ERR;
 448                     goto end;
 449                 }
 450
 451                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 452                          sizeof(sctpauthkey), sctpauthkey);
 453 #endif
 454 #ifndef OPENSSL_NO_TLSEXT
 455                 if (s->tlsext_ticket_expected)
 456                     s->state = SSL3_ST_SW_SESSION_TICKET_A;
 457                 else
 458                     s->state = SSL3_ST_SW_CHANGE_A;
 459 #else
 460                 s->state = SSL3_ST_SW_CHANGE_A;
 461 #endif
 462             } else
 463                 s->state = SSL3_ST_SW_CERT_A;
 464             s->init_num = 0;
 465             break;
 466
 467         case SSL3_ST_SW_CERT_A:
 468         case SSL3_ST_SW_CERT_B:
 469             /* Check if it is anon DH or normal PSK */
 470             if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
 471                 && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 472                 dtls1_start_timer(s);
 473                 ret = ssl3_send_server_certificate(s);
 474                 if (ret <= 0)
 475                     goto end;
 476 #ifndef OPENSSL_NO_TLSEXT
 477                 if (s->tlsext_status_expected)
 478                     s->state = SSL3_ST_SW_CERT_STATUS_A;
 479                 else
 480                     s->state = SSL3_ST_SW_KEY_EXCH_A;
 481             } else {
 482                 skip = 1;
 483                 s->state = SSL3_ST_SW_KEY_EXCH_A;
 484             }
 485 #else
 486             } else
 487                 skip = 1;
 488
 489             s->state = SSL3_ST_SW_KEY_EXCH_A;
 490 #endif
 491             s->init_num = 0;
 492             break;
 493
 494         case SSL3_ST_SW_KEY_EXCH_A:
 495         case SSL3_ST_SW_KEY_EXCH_B:
 496             alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 497
 498             /*
 499              * clear this, it may get reset by
 500              * send_server_key_exchange
 501              */
 502             s->s3->tmp.use_rsa_tmp = 0;
 503
 504             /*
 505              * only send if a DH key exchange or RSA but we have a sign only
 506              * certificate
 507              */
 508             if (0
 509                 /*
 510                  * PSK: send ServerKeyExchange if PSK identity hint if
 511                  * provided
 512                  */
 513 #ifndef OPENSSL_NO_PSK
 514                 || ((alg_k & SSL_kPSK) && s->ctx->psk_identity_hint)
 515 #endif
 516                 || (alg_k & SSL_kDHE)
 517                 || (alg_k & SSL_kEECDH)
 518                 || ((alg_k & SSL_kRSA)
 519                     && (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
 520                         || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
 521                             && EVP_PKEY_size(s->cert->pkeys
 522                                              [SSL_PKEY_RSA_ENC].privatekey) *
 523                             8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
 524                         )
 525                     )
 526                 )
 527                 ) {
 528                 dtls1_start_timer(s);
 529                 ret = ssl3_send_server_key_exchange(s);
 530                 if (ret <= 0)
 531                     goto end;
 532             } else
 533                 skip = 1;
 534
 535             s->state = SSL3_ST_SW_CERT_REQ_A;
 536             s->init_num = 0;
 537             break;
 538
 539         case SSL3_ST_SW_CERT_REQ_A:
 540         case SSL3_ST_SW_CERT_REQ_B:
 541             if (                /* don't request cert unless asked for it: */
 542                    !(s->verify_mode & SSL_VERIFY_PEER) ||
 543                    /*
 544                     * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
 545                     * during re-negotiation:
 546                     */
 547                    ((s->session->peer != NULL) &&
 548                     (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
 549                    /*
 550                     * never request cert in anonymous ciphersuites (see
 551                     * section "Certificate request" in SSL 3 drafts and in
 552                     * RFC 2246):
 553                     */
 554                    ((s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) &&
 555                     /*
 556                      * ... except when the application insists on
 557                      * verification (against the specs, but s3_clnt.c accepts
 558                      * this for SSL 3)
 559                      */
 560                     !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) ||
 561                    /*
 562                     * never request cert in Kerberos ciphersuites
 563                     */
 564                    (s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5)
 565                    /*
 566                     * With normal PSK Certificates and Certificate Requests
 567                     * are omitted
 568                     */
 569                    || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
 570                 /* no cert request */
 571                 skip = 1;
 572                 s->s3->tmp.cert_request = 0;
 573                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 574 #ifndef OPENSSL_NO_SCTP
 575                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 576                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 577                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 578                 }
 579 #endif
 580             } else {
 581                 s->s3->tmp.cert_request = 1;
 582                 dtls1_start_timer(s);
 583                 ret = ssl3_send_certificate_request(s);
 584                 if (ret <= 0)
 585                     goto end;
 586 #ifndef NETSCAPE_HANG_BUG
 587                 s->state = SSL3_ST_SW_SRVR_DONE_A;
 588 # ifndef OPENSSL_NO_SCTP
 589                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 590                     s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
 591                     s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 592                 }
 593 # endif
 594 #else
 595                 s->state = SSL3_ST_SW_FLUSH;
 596                 s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
 597 # ifndef OPENSSL_NO_SCTP
 598                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 599                     s->d1->next_state = s->s3->tmp.next_state;
 600                     s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 601                 }
 602 # endif
 603 #endif
 604                 s->init_num = 0;
 605             }
 606             break;
 607
 608         case SSL3_ST_SW_SRVR_DONE_A:
 609         case SSL3_ST_SW_SRVR_DONE_B:
 610             dtls1_start_timer(s);
 611             ret = ssl3_send_server_done(s);
 612             if (ret <= 0)
 613                 goto end;
 614             s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
 615             s->state = SSL3_ST_SW_FLUSH;
 616             s->init_num = 0;
 617             break;
 618
 619         case SSL3_ST_SW_FLUSH:
 620             s->rwstate = SSL_WRITING;
 621             if (BIO_flush(s->wbio) <= 0) {
 622                 /*
 623                  * If the write error was fatal, stop trying
 624                  */
 625                 if (!BIO_should_retry(s->wbio)) {
 626                     s->rwstate = SSL_NOTHING;
 627                     s->state = s->s3->tmp.next_state;
 628                 }
 629
 630                 ret = -1;
 631                 goto end;
 632             }
 633             s->rwstate = SSL_NOTHING;
 634             s->state = s->s3->tmp.next_state;
 635             break;
 636
 637         case SSL3_ST_SR_CERT_A:
 638         case SSL3_ST_SR_CERT_B:
 639             if (s->s3->tmp.cert_request) {
 640                 ret = ssl3_get_client_certificate(s);
 641                 if (ret <= 0)
 642                     goto end;
 643             }
 644             s->init_num = 0;
 645             s->state = SSL3_ST_SR_KEY_EXCH_A;
 646             break;
 647
 648         case SSL3_ST_SR_KEY_EXCH_A:
 649         case SSL3_ST_SR_KEY_EXCH_B:
 650             ret = ssl3_get_client_key_exchange(s);
 651             if (ret <= 0)
 652                 goto end;
 653 #ifndef OPENSSL_NO_SCTP
 654             /*
 655              * Add new shared key for SCTP-Auth, will be ignored if no SCTP
 656              * used.
 657              */
 658             snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
 659                      DTLS1_SCTP_AUTH_LABEL);
 660
 661             if (SSL_export_keying_material(s, sctpauthkey,
 662                                        sizeof(sctpauthkey), labelbuffer,
 663                                        sizeof(labelbuffer), NULL, 0, 0) <= 0) {
 664                 ret = -1;
 665                 s->state = SSL_ST_ERR;
 666                 goto end;
 667             }
 668
 669             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
 670                      sizeof(sctpauthkey), sctpauthkey);
 671 #endif
 672
 673             s->state = SSL3_ST_SR_CERT_VRFY_A;
 674             s->init_num = 0;
 675
 676             if (ret == 2) {
 677                 /*
 678                  * For the ECDH ciphersuites when the client sends its ECDH
 679                  * pub key in a certificate, the CertificateVerify message is
 680                  * not sent.
 681                  */
 682                 s->state = SSL3_ST_SR_FINISHED_A;
 683                 s->init_num = 0;
 684             } else if (SSL_USE_SIGALGS(s)) {
 685                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 686                 s->init_num = 0;
 687                 if (!s->session->peer)
 688                     break;
 689                 /*
 690                  * For sigalgs freeze the handshake buffer at this point and
 691                  * digest cached records.
 692                  */
 693                 if (!s->s3->handshake_buffer) {
 694                     SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
 695                     s->state = SSL_ST_ERR;
 696                     return -1;
 697                 }
 698                 s->s3->flags |= TLS1_FLAGS_KEEP_HANDSHAKE;
 699                 if (!ssl3_digest_cached_records(s)) {
 700                     s->state = SSL_ST_ERR;
 701                     return -1;
 702                 }
 703             } else {
 704                 s->state = SSL3_ST_SR_CERT_VRFY_A;
 705                 s->init_num = 0;
 706
 707                 /*
 708                  * We need to get hashes here so if there is a client cert,
 709                  * it can be verified
 710                  */
 711                 s->method->ssl3_enc->cert_verify_mac(s,
 712                                                      NID_md5,
 713                                                      &(s->s3->
 714                                                        tmp.cert_verify_md
 715                                                        [0]));
 716                 s->method->ssl3_enc->cert_verify_mac(s, NID_sha1,
 717                                                      &(s->s3->
 718                                                        tmp.cert_verify_md
 719                                                        [MD5_DIGEST_LENGTH]));
 720             }
 721             break;
 722
 723         case SSL3_ST_SR_CERT_VRFY_A:
 724         case SSL3_ST_SR_CERT_VRFY_B:
 725             ret = ssl3_get_cert_verify(s);
 726             if (ret <= 0)
 727                 goto end;
 728 #ifndef OPENSSL_NO_SCTP
 729             if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
 730                 state == SSL_ST_RENEGOTIATE)
 731                 s->state = DTLS1_SCTP_ST_SR_READ_SOCK;
 732             else
 733 #endif
 734                 s->state = SSL3_ST_SR_FINISHED_A;
 735             s->init_num = 0;
 736             break;
 737
 738         case SSL3_ST_SR_FINISHED_A:
 739         case SSL3_ST_SR_FINISHED_B:
 740             /*
 741              * Enable CCS. Receiving a CCS clears the flag, so make
 742              * sure not to re-enable it to ban duplicates. This *should* be the
 743              * first time we have received one - but we check anyway to be
 744              * cautious.
 745              * s->s3->change_cipher_spec is set when a CCS is
 746              * processed in d1_pkt.c, and remains set until
 747              * the client's Finished message is read.
 748              */
 749             if (!s->s3->change_cipher_spec)
 750                 s->d1->change_cipher_spec_ok = 1;
 751             ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
 752                                     SSL3_ST_SR_FINISHED_B);
 753             if (ret <= 0)
 754                 goto end;
 755             dtls1_stop_timer(s);
 756             if (s->hit)
 757                 s->state = SSL_ST_OK;
 758 #ifndef OPENSSL_NO_TLSEXT
 759             else if (s->tlsext_ticket_expected)
 760                 s->state = SSL3_ST_SW_SESSION_TICKET_A;
 761 #endif
 762             else
 763                 s->state = SSL3_ST_SW_CHANGE_A;
 764             s->init_num = 0;
 765             break;
 766
 767 #ifndef OPENSSL_NO_TLSEXT
 768         case SSL3_ST_SW_SESSION_TICKET_A:
 769         case SSL3_ST_SW_SESSION_TICKET_B:
 770             ret = ssl3_send_newsession_ticket(s);
 771             if (ret <= 0)
 772                 goto end;
 773             s->state = SSL3_ST_SW_CHANGE_A;
 774             s->init_num = 0;
 775             break;
 776
 777         case SSL3_ST_SW_CERT_STATUS_A:
 778         case SSL3_ST_SW_CERT_STATUS_B:
 779             ret = ssl3_send_cert_status(s);
 780             if (ret <= 0)
 781                 goto end;
 782             s->state = SSL3_ST_SW_KEY_EXCH_A;
 783             s->init_num = 0;
 784             break;
 785
 786 #endif
 787
 788         case SSL3_ST_SW_CHANGE_A:
 789         case SSL3_ST_SW_CHANGE_B:
 790
 791             s->session->cipher = s->s3->tmp.new_cipher;
 792             if (!s->method->ssl3_enc->setup_key_block(s)) {
 793                 ret = -1;
 794                 s->state = SSL_ST_ERR;
 795                 goto end;
 796             }
 797
 798             ret = dtls1_send_change_cipher_spec(s,
 799                                                 SSL3_ST_SW_CHANGE_A,
 800                                                 SSL3_ST_SW_CHANGE_B);
 801
 802             if (ret <= 0)
 803                 goto end;
 804
 805 #ifndef OPENSSL_NO_SCTP
 806             if (!s->hit) {
 807                 /*
 808                  * Change to new shared key of SCTP-Auth, will be ignored if
 809                  * no SCTP used.
 810                  */
 811                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 812                          0, NULL);
 813             }
 814 #endif
 815
 816             s->state = SSL3_ST_SW_FINISHED_A;
 817             s->init_num = 0;
 818
 819             if (!s->method->ssl3_enc->change_cipher_state(s,
 820                                                           SSL3_CHANGE_CIPHER_SERVER_WRITE))
 821             {
 822                 ret = -1;
 823                 s->state = SSL_ST_ERR;
 824                 goto end;
 825             }
 826
 827             dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
 828             break;
 829
 830         case SSL3_ST_SW_FINISHED_A:
 831         case SSL3_ST_SW_FINISHED_B:
 832             ret = ssl3_send_finished(s,
 833                                      SSL3_ST_SW_FINISHED_A,
 834                                      SSL3_ST_SW_FINISHED_B,
 835                                      s->method->
 836                                      ssl3_enc->server_finished_label,
 837                                      s->method->
 838                                      ssl3_enc->server_finished_label_len);
 839             if (ret <= 0)
 840                 goto end;
 841             s->state = SSL3_ST_SW_FLUSH;
 842             if (s->hit) {
 843                 s->s3->tmp.next_state = SSL3_ST_SR_FINISHED_A;
 844
 845 #ifndef OPENSSL_NO_SCTP
 846                 /*
 847                  * Change to new shared key of SCTP-Auth, will be ignored if
 848                  * no SCTP used.
 849                  */
 850                 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
 851                          0, NULL);
 852 #endif
 853             } else {
 854                 s->s3->tmp.next_state = SSL_ST_OK;
 855 #ifndef OPENSSL_NO_SCTP
 856                 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 857                     s->d1->next_state = s->s3->tmp.next_state;
 858                     s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
 859                 }
 860 #endif
 861             }
 862             s->init_num = 0;
 863             break;
 864
 865         case SSL_ST_OK:
 866             /* clean a few things up */
 867             ssl3_cleanup_key_block(s);
 868
 869 #if 0
 870             BUF_MEM_free(s->init_buf);
 871             s->init_buf = NULL;
 872 #endif
 873
 874             /* remove buffering on output */
 875             ssl_free_wbio_buffer(s);
 876
 877             s->init_num = 0;
 878
 879             if (s->renegotiate == 2) { /* skipped if we just sent a
 880                                         * HelloRequest */
 881                 s->renegotiate = 0;
 882                 s->new_session = 0;
 883
 884                 ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
 885
 886                 s->ctx->stats.sess_accept_good++;
 887                 /* s->server=1; */
 888                 s->handshake_func = dtls1_accept;
 889
 890                 if (cb != NULL)
 891                     cb(s, SSL_CB_HANDSHAKE_DONE, 1);
 892             }
 893
 894             ret = 1;
 895
 896             /* done handshaking, next message is client hello */
 897             s->d1->handshake_read_seq = 0;
 898             /* next message is server hello */
 899             s->d1->handshake_write_seq = 0;
 900             s->d1->next_handshake_write_seq = 0;
 901             dtls1_clear_received_buffer(s);
 902             goto end;
 903             /* break; */
 904
 905         case SSL_ST_ERR:
 906         default:
 907             SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
 908             ret = -1;
 909             goto end;
 910             /* break; */
 911         }
 912
 913         if (!s->s3->tmp.reuse_message && !skip) {
 914             if (s->debug) {
 915                 if ((ret = BIO_flush(s->wbio)) <= 0)
 916                     goto end;
 917             }
 918
 919             if ((cb != NULL) && (s->state != state)) {
 920                 new_state = s->state;
 921                 s->state = state;
 922                 cb(s, SSL_CB_ACCEPT_LOOP, 1);
 923                 s->state = new_state;
 924             }
 925         }
 926         skip = 0;
 927     }
 928  end:
 929     /* BIO_flush(s->wbio); */
 930
 931     s->in_handshake--;
 932 #ifndef OPENSSL_NO_SCTP
 933     /*
 934      * Notify SCTP BIO socket to leave handshake mode and prevent stream
 935      * identifier other than 0. Will be ignored if no SCTP is used.
 936      */
 937     BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
 938              s->in_handshake, NULL);
 939 #endif
 940
 941     if (cb != NULL)
 942         cb(s, SSL_CB_ACCEPT_EXIT, ret);
 943     return (ret);
 944 }
 945
 946 int dtls1_send_hello_verify_request(SSL *s)
 947 {
 948     unsigned int msg_len;
 949     unsigned char *msg, *buf, *p;
 950
 951     if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
 952         buf = (unsigned char *)s->init_buf->data;
 953
 954         msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
 955         /* Always use DTLS 1.0 version: see RFC 6347 */
 956         *(p++) = DTLS1_VERSION >> 8;
 957         *(p++) = DTLS1_VERSION & 0xFF;
 958
 959         if (s->ctx->app_gen_cookie_cb == NULL ||
 960             s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
 961                                       &(s->d1->cookie_len)) == 0) {
 962             SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
 963                    ERR_R_INTERNAL_ERROR);
 964             s->state = SSL_ST_ERR;
 965             return 0;
 966         }
 967
 968         *(p++) = (unsigned char)s->d1->cookie_len;
 969         memcpy(p, s->d1->cookie, s->d1->cookie_len);
 970         p += s->d1->cookie_len;
 971         msg_len = p - msg;
 972
 973         dtls1_set_message_header(s, buf,
 974                                  DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0,
 975                                  msg_len);
 976
 977         s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
 978         /* number of bytes to write */
 979         s->init_num = p - buf;
 980         s->init_off = 0;
 981     }
 982
 983     /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
 984     return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
 985 }