crypto/libressl/ssl/ssl_srvr.c

   1 /* $OpenBSD: ssl_srvr.c,v 1.66 2019/03/25 17:21:18 jsing Exp $ */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58 /* ====================================================================
  59  * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
  60  *
  61  * Redistribution and use in source and binary forms, with or without
  62  * modification, are permitted provided that the following conditions
  63  * are met:
  64  *
  65  * 1. Redistributions of source code must retain the above copyright
  66  *    notice, this list of conditions and the following disclaimer.
  67  *
  68  * 2. Redistributions in binary form must reproduce the above copyright
  69  *    notice, this list of conditions and the following disclaimer in
  70  *    the documentation and/or other materials provided with the
  71  *    distribution.
  72  *
  73  * 3. All advertising materials mentioning features or use of this
  74  *    software must display the following acknowledgment:
  75  *    "This product includes software developed by the OpenSSL Project
  76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  77  *
  78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  79  *    endorse or promote products derived from this software without
  80  *    prior written permission. For written permission, please contact
  81  *    openssl-core@openssl.org.
  82  *
  83  * 5. Products derived from this software may not be called "OpenSSL"
  84  *    nor may "OpenSSL" appear in their names without prior written
  85  *    permission of the OpenSSL Project.
  86  *
  87  * 6. Redistributions of any form whatsoever must retain the following
  88  *    acknowledgment:
  89  *    "This product includes software developed by the OpenSSL Project
  90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  91  *
  92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 103  * OF THE POSSIBILITY OF SUCH DAMAGE.
 104  * ====================================================================
 105  *
 106  * This product includes cryptographic software written by Eric Young
 107  * (eay@cryptsoft.com).  This product includes software written by Tim
 108  * Hudson (tjh@cryptsoft.com).
 109  *
 110  */
 111 /* ====================================================================
 112  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 113  *
 114  * Portions of the attached software ("Contribution") are developed by
 115  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
 116  *
 117  * The Contribution is licensed pursuant to the OpenSSL open source
 118  * license provided above.
 119  *
 120  * ECC cipher suite support in OpenSSL originally written by
 121  * Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories.
 122  *
 123  */
 124 /* ====================================================================
 125  * Copyright 2005 Nokia. All rights reserved.
 126  *
 127  * The portions of the attached software ("Contribution") is developed by
 128  * Nokia Corporation and is licensed pursuant to the OpenSSL open source
 129  * license.
 130  *
 131  * The Contribution, originally written by Mika Kousa and Pasi Eronen of
 132  * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
 133  * support (see RFC 4279) to OpenSSL.
 134  *
 135  * No patent licenses or other rights except those expressly stated in
 136  * the OpenSSL open source license shall be deemed granted or received
 137  * expressly, by implication, estoppel, or otherwise.
 138  *
 139  * No assurances are provided by Nokia that the Contribution does not
 140  * infringe the patent or other intellectual property rights of any third
 141  * party or that the license provides you with all the necessary rights
 142  * to make use of the Contribution.
 143  *
 144  * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
 145  * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
 146  * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
 147  * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
 148  * OTHERWISE.
 149  */
 150
 151 #include <stdio.h>
 152
 153 #include "ssl_locl.h"
 154
 155 #include <openssl/bn.h>
 156 #include <openssl/buffer.h>
 157 #include <openssl/curve25519.h>
 158 #include <openssl/evp.h>
 159 #include <openssl/dh.h>
 160 #ifndef OPENSSL_NO_GOST
 161 #include <openssl/gost.h>
 162 #endif
 163 #include <openssl/hmac.h>
 164 #include <openssl/md5.h>
 165 #include <openssl/objects.h>
 166 #include <openssl/x509.h>
 167
 168 #include "bytestring.h"
 169 #include "ssl_sigalgs.h"
 170 #include "ssl_tlsext.h"
 171
 172 int
 173 ssl3_accept(SSL *s)
 174 {
 175         void (*cb)(const SSL *ssl, int type, int val) = NULL;
 176         unsigned long alg_k;
 177         int ret = -1;
 178         int new_state, state, skip = 0;
 179         int listen = 0;
 180
 181         ERR_clear_error();
 182         errno = 0;
 183
 184         if (s->internal->info_callback != NULL)
 185                 cb = s->internal->info_callback;
 186         else if (s->ctx->internal->info_callback != NULL)
 187                 cb = s->ctx->internal->info_callback;
 188
 189         if (SSL_IS_DTLS(s))
 190                 listen = D1I(s)->listen;
 191
 192         /* init things to blank */
 193         s->internal->in_handshake++;
 194         if (!SSL_in_init(s) || SSL_in_before(s))
 195                 SSL_clear(s);
 196
 197         if (SSL_IS_DTLS(s))
 198                 D1I(s)->listen = listen;
 199
 200         for (;;) {
 201                 state = S3I(s)->hs.state;
 202
 203                 switch (S3I(s)->hs.state) {
 204                 case SSL_ST_RENEGOTIATE:
 205                         s->internal->renegotiate = 1;
 206                         /* S3I(s)->hs.state=SSL_ST_ACCEPT; */
 207
 208                 case SSL_ST_BEFORE:
 209                 case SSL_ST_ACCEPT:
 210                 case SSL_ST_BEFORE|SSL_ST_ACCEPT:
 211                 case SSL_ST_OK|SSL_ST_ACCEPT:
 212                         s->server = 1;
 213                         if (cb != NULL)
 214                                 cb(s, SSL_CB_HANDSHAKE_START, 1);
 215
 216                         if (SSL_IS_DTLS(s)) {
 217                                 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
 218                                         SSLerror(s, ERR_R_INTERNAL_ERROR);
 219                                         ret = -1;
 220                                         goto end;
 221                                 }
 222                         } else {
 223                                 if ((s->version >> 8) != 3) {
 224                                         SSLerror(s, ERR_R_INTERNAL_ERROR);
 225                                         ret = -1;
 226                                         goto end;
 227                                 }
 228                         }
 229                         s->internal->type = SSL_ST_ACCEPT;
 230
 231                         if (!ssl3_setup_init_buffer(s)) {
 232                                 ret = -1;
 233                                 goto end;
 234                         }
 235                         if (!ssl3_setup_buffers(s)) {
 236                                 ret = -1;
 237                                 goto end;
 238                         }
 239
 240                         s->internal->init_num = 0;
 241
 242                         if (S3I(s)->hs.state != SSL_ST_RENEGOTIATE) {
 243                                 /*
 244                                  * Ok, we now need to push on a buffering BIO
 245                                  * so that the output is sent in a way that
 246                                  * TCP likes :-)
 247                                  */
 248                                 if (!ssl_init_wbio_buffer(s, 1)) {
 249                                         ret = -1;
 250                                         goto end;
 251                                 }
 252
 253                                 if (!tls1_transcript_init(s)) {
 254                                         ret = -1;
 255                                         goto end;
 256                                 }
 257
 258                                 S3I(s)->hs.state = SSL3_ST_SR_CLNT_HELLO_A;
 259                                 s->ctx->internal->stats.sess_accept++;
 260                         } else if (!SSL_IS_DTLS(s) && !S3I(s)->send_connection_binding) {
 261                                 /*
 262                                  * Server attempting to renegotiate with
 263                                  * client that doesn't support secure
 264                                  * renegotiation.
 265                                  */
 266                                 SSLerror(s, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
 267                                 ssl3_send_alert(s, SSL3_AL_FATAL,
 268                                     SSL_AD_HANDSHAKE_FAILURE);
 269                                 ret = -1;
 270                                 goto end;
 271                         } else {
 272                                 /*
 273                                  * S3I(s)->hs.state == SSL_ST_RENEGOTIATE,
 274                                  * we will just send a HelloRequest.
 275                                  */
 276                                 s->ctx->internal->stats.sess_accept_renegotiate++;
 277                                 S3I(s)->hs.state = SSL3_ST_SW_HELLO_REQ_A;
 278                         }
 279                         break;
 280
 281                 case SSL3_ST_SW_HELLO_REQ_A:
 282                 case SSL3_ST_SW_HELLO_REQ_B:
 283                         s->internal->shutdown = 0;
 284                         if (SSL_IS_DTLS(s)) {
 285                                 dtls1_clear_record_buffer(s);
 286                                 dtls1_start_timer(s);
 287                         }
 288                         ret = ssl3_send_hello_request(s);
 289                         if (ret <= 0)
 290                                 goto end;
 291                         if (SSL_IS_DTLS(s))
 292                                 S3I(s)->hs.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 293                         else
 294                                 S3I(s)->hs.next_state = SSL3_ST_SW_HELLO_REQ_C;
 295                         S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
 296                         s->internal->init_num = 0;
 297
 298                         if (!tls1_transcript_init(s)) {
 299                                 ret = -1;
 300                                 goto end;
 301                         }
 302                         break;
 303
 304                 case SSL3_ST_SW_HELLO_REQ_C:
 305                         S3I(s)->hs.state = SSL_ST_OK;
 306                         break;
 307
 308                 case SSL3_ST_SR_CLNT_HELLO_A:
 309                 case SSL3_ST_SR_CLNT_HELLO_B:
 310                 case SSL3_ST_SR_CLNT_HELLO_C:
 311                         s->internal->shutdown = 0;
 312                         if (SSL_IS_DTLS(s)) {
 313                                 ret = ssl3_get_client_hello(s);
 314                                 if (ret <= 0)
 315                                         goto end;
 316                                 dtls1_stop_timer(s);
 317
 318                                 if (ret == 1 &&
 319                                     (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
 320                                         S3I(s)->hs.state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
 321                                 else
 322                                         S3I(s)->hs.state = SSL3_ST_SW_SRVR_HELLO_A;
 323
 324                                 s->internal->init_num = 0;
 325
 326                                 /*
 327                                  * Reflect ClientHello sequence to remain
 328                                  * stateless while listening.
 329                                  */
 330                                 if (listen) {
 331                                         memcpy(S3I(s)->write_sequence,
 332                                             S3I(s)->read_sequence,
 333                                             sizeof(S3I(s)->write_sequence));
 334                                 }
 335
 336                                 /* If we're just listening, stop here */
 337                                 if (listen && S3I(s)->hs.state == SSL3_ST_SW_SRVR_HELLO_A) {
 338                                         ret = 2;
 339                                         D1I(s)->listen = 0;
 340                                         /*
 341                                          * Set expected sequence numbers to
 342                                          * continue the handshake.
 343                                          */
 344                                         D1I(s)->handshake_read_seq = 2;
 345                                         D1I(s)->handshake_write_seq = 1;
 346                                         D1I(s)->next_handshake_write_seq = 1;
 347                                         goto end;
 348                                 }
 349                         } else {
 350                                 if (s->internal->rwstate != SSL_X509_LOOKUP) {
 351                                         ret = ssl3_get_client_hello(s);
 352                                         if (ret <= 0)
 353                                                 goto end;
 354                                 }
 355
 356                                 s->internal->renegotiate = 2;
 357                                 S3I(s)->hs.state = SSL3_ST_SW_SRVR_HELLO_A;
 358                                 s->internal->init_num = 0;
 359                         }
 360                         break;
 361
 362                 case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
 363                 case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
 364                         ret = dtls1_send_hello_verify_request(s);
 365                         if (ret <= 0)
 366                                 goto end;
 367                         S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
 368                         S3I(s)->hs.next_state = SSL3_ST_SR_CLNT_HELLO_A;
 369
 370                         /* HelloVerifyRequest resets Finished MAC. */
 371                         tls1_transcript_reset(s);
 372                         break;
 373
 374                 case SSL3_ST_SW_SRVR_HELLO_A:
 375                 case SSL3_ST_SW_SRVR_HELLO_B:
 376                         if (SSL_IS_DTLS(s)) {
 377                                 s->internal->renegotiate = 2;
 378                                 dtls1_start_timer(s);
 379                         }
 380                         ret = ssl3_send_server_hello(s);
 381                         if (ret <= 0)
 382                                 goto end;
 383                         if (s->internal->hit) {
 384                                 if (s->internal->tlsext_ticket_expected)
 385                                         S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_A;
 386                                 else
 387                                         S3I(s)->hs.state = SSL3_ST_SW_CHANGE_A;
 388                         } else {
 389                                 S3I(s)->hs.state = SSL3_ST_SW_CERT_A;
 390                         }
 391                         s->internal->init_num = 0;
 392                         break;
 393
 394                 case SSL3_ST_SW_CERT_A:
 395                 case SSL3_ST_SW_CERT_B:
 396                         /* Check if it is anon DH or anon ECDH. */
 397                         if (!(S3I(s)->hs.new_cipher->algorithm_auth &
 398                             SSL_aNULL)) {
 399                                 if (SSL_IS_DTLS(s))
 400                                         dtls1_start_timer(s);
 401                                 ret = ssl3_send_server_certificate(s);
 402                                 if (ret <= 0)
 403                                         goto end;
 404                                 if (s->internal->tlsext_status_expected)
 405                                         S3I(s)->hs.state = SSL3_ST_SW_CERT_STATUS_A;
 406                                 else
 407                                         S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_A;
 408                         } else {
 409                                 skip = 1;
 410                                 S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_A;
 411                         }
 412                         s->internal->init_num = 0;
 413                         break;
 414
 415                 case SSL3_ST_SW_KEY_EXCH_A:
 416                 case SSL3_ST_SW_KEY_EXCH_B:
 417                         alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
 418
 419                         /*
 420                          * Only send if using a DH key exchange.
 421                          *
 422                          * For ECC ciphersuites, we send a ServerKeyExchange
 423                          * message only if the cipher suite is ECDHE. In other
 424                          * cases, the server certificate contains the server's
 425                          * public key for key exchange.
 426                          */
 427                         if (alg_k & (SSL_kDHE|SSL_kECDHE)) {
 428                                 if (SSL_IS_DTLS(s))
 429                                         dtls1_start_timer(s);
 430                                 ret = ssl3_send_server_key_exchange(s);
 431                                 if (ret <= 0)
 432                                         goto end;
 433                         } else
 434                                 skip = 1;
 435
 436                         S3I(s)->hs.state = SSL3_ST_SW_CERT_REQ_A;
 437                         s->internal->init_num = 0;
 438                         break;
 439
 440                 case SSL3_ST_SW_CERT_REQ_A:
 441                 case SSL3_ST_SW_CERT_REQ_B:
 442                         /*
 443                          * Determine whether or not we need to request a
 444                          * certificate.
 445                          *
 446                          * Do not request a certificate if:
 447                          *
 448                          * - We did not ask for it (SSL_VERIFY_PEER is unset).
 449                          *
 450                          * - SSL_VERIFY_CLIENT_ONCE is set and we are
 451                          *   renegotiating.
 452                          *
 453                          * - We are using an anonymous ciphersuites
 454                          *   (see section "Certificate request" in SSL 3 drafts
 455                          *   and in RFC 2246) ... except when the application
 456                          *   insists on verification (against the specs, but
 457                          *   s3_clnt.c accepts this for SSL 3).
 458                          */
 459                         if (!(s->verify_mode & SSL_VERIFY_PEER) ||
 460                             ((s->session->peer != NULL) &&
 461                              (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
 462                             ((S3I(s)->hs.new_cipher->algorithm_auth &
 463                              SSL_aNULL) && !(s->verify_mode &
 464                              SSL_VERIFY_FAIL_IF_NO_PEER_CERT))) {
 465                                 /* No cert request. */
 466                                 skip = 1;
 467                                 S3I(s)->tmp.cert_request = 0;
 468                                 S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_A;
 469
 470                                 if (!SSL_IS_DTLS(s))
 471                                         tls1_transcript_free(s);
 472                         } else {
 473                                 S3I(s)->tmp.cert_request = 1;
 474                                 if (SSL_IS_DTLS(s))
 475                                         dtls1_start_timer(s);
 476                                 ret = ssl3_send_certificate_request(s);
 477                                 if (ret <= 0)
 478                                         goto end;
 479                                 S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_A;
 480                                 s->internal->init_num = 0;
 481                         }
 482                         break;
 483
 484                 case SSL3_ST_SW_SRVR_DONE_A:
 485                 case SSL3_ST_SW_SRVR_DONE_B:
 486                         if (SSL_IS_DTLS(s))
 487                                 dtls1_start_timer(s);
 488                         ret = ssl3_send_server_done(s);
 489                         if (ret <= 0)
 490                                 goto end;
 491                         S3I(s)->hs.next_state = SSL3_ST_SR_CERT_A;
 492                         S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
 493                         s->internal->init_num = 0;
 494                         break;
 495
 496                 case SSL3_ST_SW_FLUSH:
 497                         /*
 498                          * This code originally checked to see if
 499                          * any data was pending using BIO_CTRL_INFO
 500                          * and then flushed. This caused problems
 501                          * as documented in PR#1939. The proposed
 502                          * fix doesn't completely resolve this issue
 503                          * as buggy implementations of BIO_CTRL_PENDING
 504                          * still exist. So instead we just flush
 505                          * unconditionally.
 506                          */
 507                         s->internal->rwstate = SSL_WRITING;
 508                         if (BIO_flush(s->wbio) <= 0) {
 509                                 if (SSL_IS_DTLS(s)) {
 510                                         /* If the write error was fatal, stop trying. */
 511                                         if (!BIO_should_retry(s->wbio)) {
 512                                                 s->internal->rwstate = SSL_NOTHING;
 513                                                 S3I(s)->hs.state = S3I(s)->hs.next_state;
 514                                         }
 515                                 }
 516                                 ret = -1;
 517                                 goto end;
 518                         }
 519                         s->internal->rwstate = SSL_NOTHING;
 520                         S3I(s)->hs.state = S3I(s)->hs.next_state;
 521                         break;
 522
 523                 case SSL3_ST_SR_CERT_A:
 524                 case SSL3_ST_SR_CERT_B:
 525                         if (S3I(s)->tmp.cert_request) {
 526                                 ret = ssl3_get_client_certificate(s);
 527                                 if (ret <= 0)
 528                                         goto end;
 529                         }
 530                         s->internal->init_num = 0;
 531                         S3I(s)->hs.state = SSL3_ST_SR_KEY_EXCH_A;
 532                         break;
 533
 534                 case SSL3_ST_SR_KEY_EXCH_A:
 535                 case SSL3_ST_SR_KEY_EXCH_B:
 536                         ret = ssl3_get_client_key_exchange(s);
 537                         if (ret <= 0)
 538                                 goto end;
 539
 540                         if (SSL_IS_DTLS(s)) {
 541                                 S3I(s)->hs.state = SSL3_ST_SR_CERT_VRFY_A;
 542                                 s->internal->init_num = 0;
 543                         }
 544
 545                         alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
 546                         if (ret == 2) {
 547                                 /*
 548                                  * For the ECDH ciphersuites when
 549                                  * the client sends its ECDH pub key in
 550                                  * a certificate, the CertificateVerify
 551                                  * message is not sent.
 552                                  * Also for GOST ciphersuites when
 553                                  * the client uses its key from the certificate
 554                                  * for key exchange.
 555                                  */
 556                                 S3I(s)->hs.state = SSL3_ST_SR_FINISHED_A;
 557                                 s->internal->init_num = 0;
 558                         } else if (SSL_USE_SIGALGS(s) || (alg_k & SSL_kGOST)) {
 559                                 S3I(s)->hs.state = SSL3_ST_SR_CERT_VRFY_A;
 560                                 s->internal->init_num = 0;
 561                                 if (!s->session->peer)
 562                                         break;
 563                                 /*
 564                                  * Freeze the transcript for use during client
 565                                  * certificate verification.
 566                                  */
 567                                 tls1_transcript_freeze(s);
 568                         } else {
 569                                 S3I(s)->hs.state = SSL3_ST_SR_CERT_VRFY_A;
 570                                 s->internal->init_num = 0;
 571
 572                                 tls1_transcript_free(s);
 573
 574                                 /*
 575                                  * We need to get hashes here so if there is
 576                                  * a client cert, it can be verified.
 577                                  */
 578                                 if (!tls1_transcript_hash_value(s,
 579                                     S3I(s)->tmp.cert_verify_md,
 580                                     sizeof(S3I(s)->tmp.cert_verify_md),
 581                                     NULL)) {
 582                                         ret = -1;
 583                                         goto end;
 584                                 }
 585                         }
 586                         break;
 587
 588                 case SSL3_ST_SR_CERT_VRFY_A:
 589                 case SSL3_ST_SR_CERT_VRFY_B:
 590                         if (SSL_IS_DTLS(s))
 591                                 D1I(s)->change_cipher_spec_ok = 1;
 592                         else
 593                                 s->s3->flags |= SSL3_FLAGS_CCS_OK;
 594
 595                         /* we should decide if we expected this one */
 596                         ret = ssl3_get_cert_verify(s);
 597                         if (ret <= 0)
 598                                 goto end;
 599                         S3I(s)->hs.state = SSL3_ST_SR_FINISHED_A;
 600                         s->internal->init_num = 0;
 601                         break;
 602
 603                 case SSL3_ST_SR_FINISHED_A:
 604                 case SSL3_ST_SR_FINISHED_B:
 605                         if (SSL_IS_DTLS(s))
 606                                 D1I(s)->change_cipher_spec_ok = 1;
 607                         else
 608                                 s->s3->flags |= SSL3_FLAGS_CCS_OK;
 609                         ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
 610                             SSL3_ST_SR_FINISHED_B);
 611                         if (ret <= 0)
 612                                 goto end;
 613                         if (SSL_IS_DTLS(s))
 614                                 dtls1_stop_timer(s);
 615                         if (s->internal->hit)
 616                                 S3I(s)->hs.state = SSL_ST_OK;
 617                         else if (s->internal->tlsext_ticket_expected)
 618                                 S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_A;
 619                         else
 620                                 S3I(s)->hs.state = SSL3_ST_SW_CHANGE_A;
 621                         s->internal->init_num = 0;
 622                         break;
 623
 624                 case SSL3_ST_SW_SESSION_TICKET_A:
 625                 case SSL3_ST_SW_SESSION_TICKET_B:
 626                         ret = ssl3_send_newsession_ticket(s);
 627                         if (ret <= 0)
 628                                 goto end;
 629                         S3I(s)->hs.state = SSL3_ST_SW_CHANGE_A;
 630                         s->internal->init_num = 0;
 631                         break;
 632
 633                 case SSL3_ST_SW_CERT_STATUS_A:
 634                 case SSL3_ST_SW_CERT_STATUS_B:
 635                         ret = ssl3_send_cert_status(s);
 636                         if (ret <= 0)
 637                                 goto end;
 638                         S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_A;
 639                         s->internal->init_num = 0;
 640                         break;
 641
 642                 case SSL3_ST_SW_CHANGE_A:
 643                 case SSL3_ST_SW_CHANGE_B:
 644                         s->session->cipher = S3I(s)->hs.new_cipher;
 645                         if (!tls1_setup_key_block(s)) {
 646                                 ret = -1;
 647                                 goto end;
 648                         }
 649
 650                         ret = ssl3_send_change_cipher_spec(s,
 651                             SSL3_ST_SW_CHANGE_A, SSL3_ST_SW_CHANGE_B);
 652                         if (ret <= 0)
 653                                 goto end;
 654                         S3I(s)->hs.state = SSL3_ST_SW_FINISHED_A;
 655                         s->internal->init_num = 0;
 656
 657                         if (!tls1_change_cipher_state(s,
 658                             SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
 659                                 ret = -1;
 660                                 goto end;
 661                         }
 662
 663                         if (SSL_IS_DTLS(s))
 664                                 dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
 665                         break;
 666
 667                 case SSL3_ST_SW_FINISHED_A:
 668                 case SSL3_ST_SW_FINISHED_B:
 669                         ret = ssl3_send_finished(s,
 670                             SSL3_ST_SW_FINISHED_A, SSL3_ST_SW_FINISHED_B,
 671                             TLS_MD_SERVER_FINISH_CONST,
 672                             TLS_MD_SERVER_FINISH_CONST_SIZE);
 673                         if (ret <= 0)
 674                                 goto end;
 675                         S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
 676                         if (s->internal->hit) {
 677                                 S3I(s)->hs.next_state = SSL3_ST_SR_FINISHED_A;
 678                                 tls1_transcript_free(s);
 679                         } else
 680                                 S3I(s)->hs.next_state = SSL_ST_OK;
 681                         s->internal->init_num = 0;
 682                         break;
 683
 684                 case SSL_ST_OK:
 685                         /* clean a few things up */
 686                         tls1_cleanup_key_block(s);
 687
 688                         if (S3I(s)->handshake_transcript != NULL) {
 689                                 SSLerror(s, ERR_R_INTERNAL_ERROR);
 690                                 ret = -1;
 691                                 goto end;
 692                         }
 693
 694                         if (!SSL_IS_DTLS(s)) {
 695                                 BUF_MEM_free(s->internal->init_buf);
 696                                 s->internal->init_buf = NULL;
 697                         }
 698
 699                         /* remove buffering on output */
 700                         ssl_free_wbio_buffer(s);
 701
 702                         s->internal->init_num = 0;
 703
 704                         /* Skipped if we just sent a HelloRequest. */
 705                         if (s->internal->renegotiate == 2) {
 706                                 s->internal->renegotiate = 0;
 707                                 s->internal->new_session = 0;
 708
 709                                 ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
 710
 711                                 s->ctx->internal->stats.sess_accept_good++;
 712                                 /* s->server=1; */
 713                                 s->internal->handshake_func = ssl3_accept;
 714
 715                                 if (cb != NULL)
 716                                         cb(s, SSL_CB_HANDSHAKE_DONE, 1);
 717                         }
 718
 719                         ret = 1;
 720
 721                         if (SSL_IS_DTLS(s)) {
 722                                 /* Done handshaking, next message is client hello. */
 723                                 D1I(s)->handshake_read_seq = 0;
 724                                 /* Next message is server hello. */
 725                                 D1I(s)->handshake_write_seq = 0;
 726                                 D1I(s)->next_handshake_write_seq = 0;
 727                         }
 728                         goto end;
 729                         /* break; */
 730
 731                 default:
 732                         SSLerror(s, SSL_R_UNKNOWN_STATE);
 733                         ret = -1;
 734                         goto end;
 735                         /* break; */
 736                 }
 737
 738                 if (!S3I(s)->tmp.reuse_message && !skip) {
 739                         if (s->internal->debug) {
 740                                 if ((ret = BIO_flush(s->wbio)) <= 0)
 741                                         goto end;
 742                         }
 743
 744
 745                         if ((cb != NULL) && (S3I(s)->hs.state != state)) {
 746                                 new_state = S3I(s)->hs.state;
 747                                 S3I(s)->hs.state = state;
 748                                 cb(s, SSL_CB_ACCEPT_LOOP, 1);
 749                                 S3I(s)->hs.state = new_state;
 750                         }
 751                 }
 752                 skip = 0;
 753         }
 754 end:
 755         /* BIO_flush(s->wbio); */
 756         s->internal->in_handshake--;
 757         if (cb != NULL)
 758                 cb(s, SSL_CB_ACCEPT_EXIT, ret);
 759
 760         return (ret);
 761 }
 762
 763 int
 764 ssl3_send_hello_request(SSL *s)
 765 {
 766         CBB cbb, hello;
 767
 768         memset(&cbb, 0, sizeof(cbb));
 769
 770         if (S3I(s)->hs.state == SSL3_ST_SW_HELLO_REQ_A) {
 771                 if (!ssl3_handshake_msg_start(s, &cbb, &hello,
 772                     SSL3_MT_HELLO_REQUEST))
 773                         goto err;
 774                 if (!ssl3_handshake_msg_finish(s, &cbb))
 775                         goto err;
 776
 777                 S3I(s)->hs.state = SSL3_ST_SW_HELLO_REQ_B;
 778         }
 779
 780         /* SSL3_ST_SW_HELLO_REQ_B */
 781         return (ssl3_handshake_write(s));
 782
 783  err:
 784         CBB_cleanup(&cbb);
 785
 786         return (-1);
 787 }
 788
 789 int
 790 ssl3_get_client_hello(SSL *s)
 791 {
 792         CBS cbs, client_random, session_id, cookie, cipher_suites;
 793         CBS compression_methods;
 794         uint16_t client_version;
 795         uint8_t comp_method;
 796         int comp_null;
 797         int i, j, ok, al, ret = -1, cookie_valid = 0;
 798         long n;
 799         unsigned long id;
 800         SSL_CIPHER *c;
 801         STACK_OF(SSL_CIPHER) *ciphers = NULL;
 802         unsigned long alg_k;
 803         const SSL_METHOD *method;
 804         uint16_t shared_version;
 805
 806         /*
 807          * We do this so that we will respond with our native type.
 808          * If we are TLSv1 and we get SSLv3, we will respond with TLSv1,
 809          * This down switching should be handled by a different method.
 810          * If we are SSLv3, we will respond with SSLv3, even if prompted with
 811          * TLSv1.
 812          */
 813         if (S3I(s)->hs.state == SSL3_ST_SR_CLNT_HELLO_A) {
 814                 S3I(s)->hs.state = SSL3_ST_SR_CLNT_HELLO_B;
 815         }
 816
 817         s->internal->first_packet = 1;
 818         n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_CLNT_HELLO_B,
 819             SSL3_ST_SR_CLNT_HELLO_C, SSL3_MT_CLIENT_HELLO,
 820             SSL3_RT_MAX_PLAIN_LENGTH, &ok);
 821         if (!ok)
 822                 return ((int)n);
 823         s->internal->first_packet = 0;
 824
 825         if (n < 0)
 826                 goto err;
 827
 828         CBS_init(&cbs, s->internal->init_msg, n);
 829
 830         /* Parse client hello up until the extensions (if any). */
 831         if (!CBS_get_u16(&cbs, &client_version))
 832                 goto truncated;
 833         if (!CBS_get_bytes(&cbs, &client_random, SSL3_RANDOM_SIZE))
 834                 goto truncated;
 835         if (!CBS_get_u8_length_prefixed(&cbs, &session_id))
 836                 goto truncated;
 837         if (SSL_IS_DTLS(s)) {
 838                 if (!CBS_get_u8_length_prefixed(&cbs, &cookie))
 839                         goto truncated;
 840         }
 841         if (!CBS_get_u16_length_prefixed(&cbs, &cipher_suites))
 842                 goto truncated;
 843         if (!CBS_get_u8_length_prefixed(&cbs, &compression_methods))
 844                 goto truncated;
 845
 846         /*
 847          * Use version from inside client hello, not from record header.
 848          * (may differ: see RFC 2246, Appendix E, second paragraph)
 849          */
 850         if (ssl_max_shared_version(s, client_version, &shared_version) != 1) {
 851                 SSLerror(s, SSL_R_WRONG_VERSION_NUMBER);
 852                 if ((s->client_version >> 8) == SSL3_VERSION_MAJOR &&
 853                     !s->internal->enc_write_ctx && !s->internal->write_hash) {
 854                         /*
 855                          * Similar to ssl3_get_record, send alert using remote
 856                          * version number.
 857                          */
 858                         s->version = s->client_version;
 859                 }
 860                 al = SSL_AD_PROTOCOL_VERSION;
 861                 goto f_err;
 862         }
 863         s->client_version = client_version;
 864         s->version = shared_version;
 865
 866         if ((method = tls1_get_server_method(shared_version)) == NULL)
 867                 method = dtls1_get_server_method(shared_version);
 868         if (method == NULL) {
 869                 SSLerror(s, ERR_R_INTERNAL_ERROR);
 870                 goto err;
 871         }
 872         s->method = method;
 873
 874         /*
 875          * If we require cookies (DTLS) and this ClientHello does not contain
 876          * one, just return since we do not want to allocate any memory yet.
 877          * So check cookie length...
 878          */
 879         if (SSL_IS_DTLS(s)) {
 880                 if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
 881                         if (CBS_len(&cookie) == 0)
 882                                 return (1);
 883                 }
 884         }
 885
 886         if (!CBS_write_bytes(&client_random, s->s3->client_random,
 887             sizeof(s->s3->client_random), NULL))
 888                 goto err;
 889
 890         s->internal->hit = 0;
 891
 892         /*
 893          * Versions before 0.9.7 always allow clients to resume sessions in
 894          * renegotiation. 0.9.7 and later allow this by default, but optionally
 895          * ignore resumption requests with flag
 896          * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag
 897          * rather than a change to default behavior so that applications
 898          * relying on this for security won't even compile against older
 899          * library versions).
 900          *
 901          * 1.0.1 and later also have a function SSL_renegotiate_abbreviated()
 902          * to request renegotiation but not a new session (s->internal->new_session
 903          * remains unset): for servers, this essentially just means that the
 904          * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
 905          * ignored.
 906          */
 907         if ((s->internal->new_session && (s->internal->options &
 908             SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
 909                 if (!ssl_get_new_session(s, 1))
 910                         goto err;
 911         } else {
 912                 CBS ext_block;
 913
 914                 CBS_dup(&cbs, &ext_block);
 915
 916                 i = ssl_get_prev_session(s, CBS_data(&session_id),
 917                     CBS_len(&session_id), &ext_block);
 918                 if (i == 1) { /* previous session */
 919                         s->internal->hit = 1;
 920                 } else if (i == -1)
 921                         goto err;
 922                 else {
 923                         /* i == 0 */
 924                         if (!ssl_get_new_session(s, 1))
 925                                 goto err;
 926                 }
 927         }
 928
 929         if (SSL_IS_DTLS(s)) {
 930                 /*
 931                  * The ClientHello may contain a cookie even if the HelloVerify
 932                  * message has not been sent - make sure that it does not cause
 933                  * an overflow.
 934                  */
 935                 if (CBS_len(&cookie) > sizeof(D1I(s)->rcvd_cookie)) {
 936                         al = SSL_AD_DECODE_ERROR;
 937                         SSLerror(s, SSL_R_COOKIE_MISMATCH);
 938                         goto f_err;
 939                 }
 940
 941                 /* Verify the cookie if appropriate option is set. */
 942                 if ((SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) &&
 943                     CBS_len(&cookie) > 0) {
 944                         size_t cookie_len;
 945
 946                         /* XXX - rcvd_cookie seems to only be used here... */
 947                         if (!CBS_write_bytes(&cookie, D1I(s)->rcvd_cookie,
 948                             sizeof(D1I(s)->rcvd_cookie), &cookie_len))
 949                                 goto err;
 950
 951                         if (s->ctx->internal->app_verify_cookie_cb != NULL) {
 952                                 if (s->ctx->internal->app_verify_cookie_cb(s,
 953                                     D1I(s)->rcvd_cookie, cookie_len) == 0) {
 954                                         al = SSL_AD_HANDSHAKE_FAILURE;
 955                                         SSLerror(s, SSL_R_COOKIE_MISMATCH);
 956                                         goto f_err;
 957                                 }
 958                                 /* else cookie verification succeeded */
 959                         /* XXX - can d1->cookie_len > sizeof(rcvd_cookie) ? */
 960                         } else if (timingsafe_memcmp(D1I(s)->rcvd_cookie,
 961                             D1I(s)->cookie, D1I(s)->cookie_len) != 0) {
 962                                 /* default verification */
 963                                 al = SSL_AD_HANDSHAKE_FAILURE;
 964                                 SSLerror(s, SSL_R_COOKIE_MISMATCH);
 965                                 goto f_err;
 966                         }
 967                         cookie_valid = 1;
 968                 }
 969         }
 970
 971         /* XXX - This logic seems wrong... */
 972         if (CBS_len(&cipher_suites) == 0 && CBS_len(&session_id) != 0) {
 973                 /* we need a cipher if we are not resuming a session */
 974                 al = SSL_AD_ILLEGAL_PARAMETER;
 975                 SSLerror(s, SSL_R_NO_CIPHERS_SPECIFIED);
 976                 goto f_err;
 977         }
 978
 979         if (CBS_len(&cipher_suites) > 0) {
 980                 if ((ciphers = ssl_bytes_to_cipher_list(s,
 981                     &cipher_suites)) == NULL)
 982                         goto err;
 983         }
 984
 985         /* If it is a hit, check that the cipher is in the list */
 986         /* XXX - CBS_len(&cipher_suites) will always be zero here... */
 987         if (s->internal->hit && CBS_len(&cipher_suites) > 0) {
 988                 j = 0;
 989                 id = s->session->cipher->id;
 990
 991                 for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
 992                         c = sk_SSL_CIPHER_value(ciphers, i);
 993                         if (c->id == id) {
 994                                 j = 1;
 995                                 break;
 996                         }
 997                 }
 998                 if (j == 0) {
 999                         /*
1000                          * We need to have the cipher in the cipher
1001                          * list if we are asked to reuse it
1002                          */
1003                         al = SSL_AD_ILLEGAL_PARAMETER;
1004                         SSLerror(s, SSL_R_REQUIRED_CIPHER_MISSING);
1005                         goto f_err;
1006                 }
1007         }
1008
1009         comp_null = 0;
1010         while (CBS_len(&compression_methods) > 0) {
1011                 if (!CBS_get_u8(&compression_methods, &comp_method))
1012                         goto truncated;
1013                 if (comp_method == 0)
1014                         comp_null = 1;
1015         }
1016         if (comp_null == 0) {
1017                 al = SSL_AD_DECODE_ERROR;
1018                 SSLerror(s, SSL_R_NO_COMPRESSION_SPECIFIED);
1019                 goto f_err;
1020         }
1021
1022         if (!tlsext_server_parse(s, &cbs, &al, SSL_TLSEXT_MSG_CH)) {
1023                 SSLerror(s, SSL_R_PARSE_TLSEXT);
1024                 goto f_err;
1025         }
1026
1027         if (!S3I(s)->renegotiate_seen && s->internal->renegotiate) {
1028                 al = SSL_AD_HANDSHAKE_FAILURE;
1029                 SSLerror(s, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
1030                 goto f_err;
1031         }
1032
1033         if (ssl_check_clienthello_tlsext_early(s) <= 0) {
1034                 SSLerror(s, SSL_R_CLIENTHELLO_TLSEXT);
1035                 goto err;
1036         }
1037
1038         /*
1039          * Check if we want to use external pre-shared secret for this
1040          * handshake for not reused session only. We need to generate
1041          * server_random before calling tls_session_secret_cb in order to allow
1042          * SessionTicket processing to use it in key derivation.
1043          */
1044         arc4random_buf(s->s3->server_random, SSL3_RANDOM_SIZE);
1045
1046         if (!s->internal->hit && s->internal->tls_session_secret_cb) {
1047                 SSL_CIPHER *pref_cipher = NULL;
1048
1049                 s->session->master_key_length = sizeof(s->session->master_key);
1050                 if (s->internal->tls_session_secret_cb(s, s->session->master_key,
1051                     &s->session->master_key_length, ciphers, &pref_cipher,
1052                     s->internal->tls_session_secret_cb_arg)) {
1053                         s->internal->hit = 1;
1054                         s->session->ciphers = ciphers;
1055                         s->session->verify_result = X509_V_OK;
1056
1057                         ciphers = NULL;
1058
1059                         /* check if some cipher was preferred by call back */
1060                         pref_cipher = pref_cipher ? pref_cipher :
1061                             ssl3_choose_cipher(s, s->session->ciphers,
1062                             SSL_get_ciphers(s));
1063                         if (pref_cipher == NULL) {
1064                                 al = SSL_AD_HANDSHAKE_FAILURE;
1065                                 SSLerror(s, SSL_R_NO_SHARED_CIPHER);
1066                                 goto f_err;
1067                         }
1068
1069                         s->session->cipher = pref_cipher;
1070
1071                         sk_SSL_CIPHER_free(s->cipher_list);
1072                         sk_SSL_CIPHER_free(s->internal->cipher_list_by_id);
1073
1074                         s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
1075                         s->internal->cipher_list_by_id =
1076                             sk_SSL_CIPHER_dup(s->session->ciphers);
1077                 }
1078         }
1079
1080         /*
1081          * Given s->session->ciphers and SSL_get_ciphers, we must
1082          * pick a cipher
1083          */
1084
1085         if (!s->internal->hit) {
1086                 sk_SSL_CIPHER_free(s->session->ciphers);
1087                 s->session->ciphers = ciphers;
1088                 if (ciphers == NULL) {
1089                         al = SSL_AD_ILLEGAL_PARAMETER;
1090                         SSLerror(s, SSL_R_NO_CIPHERS_PASSED);
1091                         goto f_err;
1092                 }
1093                 ciphers = NULL;
1094                 c = ssl3_choose_cipher(s, s->session->ciphers,
1095                 SSL_get_ciphers(s));
1096
1097                 if (c == NULL) {
1098                         al = SSL_AD_HANDSHAKE_FAILURE;
1099                         SSLerror(s, SSL_R_NO_SHARED_CIPHER);
1100                         goto f_err;
1101                 }
1102                 S3I(s)->hs.new_cipher = c;
1103         } else {
1104                 S3I(s)->hs.new_cipher = s->session->cipher;
1105         }
1106
1107         if (!tls1_transcript_hash_init(s))
1108                 goto err;
1109
1110         alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
1111         if (!(SSL_USE_SIGALGS(s) || (alg_k & SSL_kGOST)) ||
1112             !(s->verify_mode & SSL_VERIFY_PEER))
1113                 tls1_transcript_free(s);
1114
1115         /*
1116          * We now have the following setup.
1117          * client_random
1118          * cipher_list          - our prefered list of ciphers
1119          * ciphers              - the clients prefered list of ciphers
1120          * compression          - basically ignored right now
1121          * ssl version is set   - sslv3
1122          * s->session           - The ssl session has been setup.
1123          * s->internal->hit             - session reuse flag
1124          * s->hs.new_cipher     - the new cipher to use.
1125          */
1126
1127         /* Handles TLS extensions that we couldn't check earlier */
1128         if (ssl_check_clienthello_tlsext_late(s) <= 0) {
1129                 SSLerror(s, SSL_R_CLIENTHELLO_TLSEXT);
1130                 goto err;
1131         }
1132
1133         ret = cookie_valid ? 2 : 1;
1134
1135         if (0) {
1136 truncated:
1137                 al = SSL_AD_DECODE_ERROR;
1138                 SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1139 f_err:
1140                 ssl3_send_alert(s, SSL3_AL_FATAL, al);
1141         }
1142 err:
1143         sk_SSL_CIPHER_free(ciphers);
1144
1145         return (ret);
1146 }
1147
1148 int
1149 ssl3_send_server_hello(SSL *s)
1150 {
1151         CBB cbb, server_hello, session_id;
1152         size_t sl;
1153
1154         memset(&cbb, 0, sizeof(cbb));
1155
1156         if (S3I(s)->hs.state == SSL3_ST_SW_SRVR_HELLO_A) {
1157                 if (!ssl3_handshake_msg_start(s, &cbb, &server_hello,
1158                     SSL3_MT_SERVER_HELLO))
1159                         goto err;
1160
1161                 if (!CBB_add_u16(&server_hello, s->version))
1162                         goto err;
1163                 if (!CBB_add_bytes(&server_hello, s->s3->server_random,
1164                     sizeof(s->s3->server_random)))
1165                         goto err;
1166
1167                 /*
1168                  * There are several cases for the session ID to send
1169                  * back in the server hello:
1170                  *
1171                  * - For session reuse from the session cache,
1172                  *   we send back the old session ID.
1173                  * - If stateless session reuse (using a session ticket)
1174                  *   is successful, we send back the client's "session ID"
1175                  *   (which doesn't actually identify the session).
1176                  * - If it is a new session, we send back the new
1177                  *   session ID.
1178                  * - However, if we want the new session to be single-use,
1179                  *   we send back a 0-length session ID.
1180                  *
1181                  * s->internal->hit is non-zero in either case of session reuse,
1182                  * so the following won't overwrite an ID that we're supposed
1183                  * to send back.
1184                  */
1185                 if (!(s->ctx->internal->session_cache_mode & SSL_SESS_CACHE_SERVER)
1186                     && !s->internal->hit)
1187                         s->session->session_id_length = 0;
1188
1189                 sl = s->session->session_id_length;
1190                 if (sl > sizeof(s->session->session_id)) {
1191                         SSLerror(s, ERR_R_INTERNAL_ERROR);
1192                         goto err;
1193                 }
1194                 if (!CBB_add_u8_length_prefixed(&server_hello, &session_id))
1195                         goto err;
1196                 if (!CBB_add_bytes(&session_id, s->session->session_id, sl))
1197                         goto err;
1198
1199                 /* Cipher suite. */
1200                 if (!CBB_add_u16(&server_hello,
1201                     ssl3_cipher_get_value(S3I(s)->hs.new_cipher)))
1202                         goto err;
1203
1204                 /* Compression method (null). */
1205                 if (!CBB_add_u8(&server_hello, 0))
1206                         goto err;
1207
1208                 /* TLS extensions */
1209                 if (!tlsext_server_build(s, &server_hello, SSL_TLSEXT_MSG_SH)) {
1210                         SSLerror(s, ERR_R_INTERNAL_ERROR);
1211                         goto err;
1212                 }
1213
1214                 if (!ssl3_handshake_msg_finish(s, &cbb))
1215                         goto err;
1216         }
1217
1218         /* SSL3_ST_SW_SRVR_HELLO_B */
1219         return (ssl3_handshake_write(s));
1220
1221  err:
1222         CBB_cleanup(&cbb);
1223
1224         return (-1);
1225 }
1226
1227 int
1228 ssl3_send_server_done(SSL *s)
1229 {
1230         CBB cbb, done;
1231
1232         memset(&cbb, 0, sizeof(cbb));
1233
1234         if (S3I(s)->hs.state == SSL3_ST_SW_SRVR_DONE_A) {
1235                 if (!ssl3_handshake_msg_start(s, &cbb, &done,
1236                     SSL3_MT_SERVER_DONE))
1237                         goto err;
1238                 if (!ssl3_handshake_msg_finish(s, &cbb))
1239                         goto err;
1240
1241                 S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_B;
1242         }
1243
1244         /* SSL3_ST_SW_SRVR_DONE_B */
1245         return (ssl3_handshake_write(s));
1246
1247  err:
1248         CBB_cleanup(&cbb);
1249
1250         return (-1);
1251 }
1252
1253 static int
1254 ssl3_send_server_kex_dhe(SSL *s, CBB *cbb)
1255 {
1256         CBB dh_p, dh_g, dh_Ys;
1257         DH *dh = NULL, *dhp;
1258         unsigned char *data;
1259         int al;
1260
1261         if (s->cert->dh_tmp_auto != 0) {
1262                 if ((dhp = ssl_get_auto_dh(s)) == NULL) {
1263                         al = SSL_AD_INTERNAL_ERROR;
1264                         SSLerror(s, ERR_R_INTERNAL_ERROR);
1265                         goto f_err;
1266                 }
1267         } else
1268                 dhp = s->cert->dh_tmp;
1269
1270         if (dhp == NULL && s->cert->dh_tmp_cb != NULL)
1271                 dhp = s->cert->dh_tmp_cb(s, 0,
1272                     SSL_C_PKEYLENGTH(S3I(s)->hs.new_cipher));
1273
1274         if (dhp == NULL) {
1275                 al = SSL_AD_HANDSHAKE_FAILURE;
1276                 SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
1277                 goto f_err;
1278         }
1279
1280         if (S3I(s)->tmp.dh != NULL) {
1281                 SSLerror(s, ERR_R_INTERNAL_ERROR);
1282                 goto err;
1283         }
1284
1285         if (s->cert->dh_tmp_auto != 0) {
1286                 dh = dhp;
1287         } else if ((dh = DHparams_dup(dhp)) == NULL) {
1288                 SSLerror(s, ERR_R_DH_LIB);
1289                 goto err;
1290         }
1291         S3I(s)->tmp.dh = dh;
1292         if (!DH_generate_key(dh)) {
1293                 SSLerror(s, ERR_R_DH_LIB);
1294                 goto err;
1295         }
1296
1297         /*
1298          * Serialize the DH parameters and public key.
1299          */
1300         if (!CBB_add_u16_length_prefixed(cbb, &dh_p))
1301                 goto err;
1302         if (!CBB_add_space(&dh_p, &data, BN_num_bytes(dh->p)))
1303                 goto err;
1304         BN_bn2bin(dh->p, data);
1305
1306         if (!CBB_add_u16_length_prefixed(cbb, &dh_g))
1307                 goto err;
1308         if (!CBB_add_space(&dh_g, &data, BN_num_bytes(dh->g)))
1309                 goto err;
1310         BN_bn2bin(dh->g, data);
1311
1312         if (!CBB_add_u16_length_prefixed(cbb, &dh_Ys))
1313                 goto err;
1314         if (!CBB_add_space(&dh_Ys, &data, BN_num_bytes(dh->pub_key)))
1315                 goto err;
1316         BN_bn2bin(dh->pub_key, data);
1317
1318         if (!CBB_flush(cbb))
1319                 goto err;
1320
1321         return (1);
1322
1323  f_err:
1324         ssl3_send_alert(s, SSL3_AL_FATAL, al);
1325  err:
1326         return (-1);
1327 }
1328
1329 static int
1330 ssl3_send_server_kex_ecdhe_ecp(SSL *s, int nid, CBB *cbb)
1331 {
1332         const EC_GROUP *group;
1333         const EC_POINT *pubkey;
1334         unsigned char *data;
1335         int encoded_len = 0;
1336         int curve_id = 0;
1337         BN_CTX *bn_ctx = NULL;
1338         EC_KEY *ecdh;
1339         CBB ecpoint;
1340         int al;
1341
1342         /*
1343          * Only named curves are supported in ECDH ephemeral key exchanges.
1344          * For supported named curves, curve_id is non-zero.
1345          */
1346         if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
1347                 SSLerror(s, SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
1348                 goto err;
1349         }
1350
1351         if (S3I(s)->tmp.ecdh != NULL) {
1352                 SSLerror(s, ERR_R_INTERNAL_ERROR);
1353                 goto err;
1354         }
1355
1356         if ((S3I(s)->tmp.ecdh = EC_KEY_new_by_curve_name(nid)) == NULL) {
1357                 al = SSL_AD_HANDSHAKE_FAILURE;
1358                 SSLerror(s, SSL_R_MISSING_TMP_ECDH_KEY);
1359                 goto f_err;
1360         }
1361         ecdh = S3I(s)->tmp.ecdh;
1362
1363         if (!EC_KEY_generate_key(ecdh)) {
1364                 SSLerror(s, ERR_R_ECDH_LIB);
1365                 goto err;
1366         }
1367         if ((group = EC_KEY_get0_group(ecdh)) == NULL ||
1368             (pubkey = EC_KEY_get0_public_key(ecdh)) == NULL ||
1369             EC_KEY_get0_private_key(ecdh) == NULL) {
1370                 SSLerror(s, ERR_R_ECDH_LIB);
1371                 goto err;
1372         }
1373
1374         /*
1375          * Encode the public key.
1376          */
1377         encoded_len = EC_POINT_point2oct(group, pubkey,
1378             POINT_CONVERSION_UNCOMPRESSED, NULL, 0, NULL);
1379         if (encoded_len == 0) {
1380                 SSLerror(s, ERR_R_ECDH_LIB);
1381                 goto err;
1382         }
1383         if ((bn_ctx = BN_CTX_new()) == NULL) {
1384                 SSLerror(s, ERR_R_MALLOC_FAILURE);
1385                 goto err;
1386         }
1387
1388         /*
1389          * Only named curves are supported in ECDH ephemeral key exchanges.
1390          * In this case the ServerKeyExchange message has:
1391          * [1 byte CurveType], [2 byte CurveName]
1392          * [1 byte length of encoded point], followed by
1393          * the actual encoded point itself.
1394          */
1395         if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
1396                 goto err;
1397         if (!CBB_add_u16(cbb, curve_id))
1398                 goto err;
1399         if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
1400                 goto err;
1401         if (!CBB_add_space(&ecpoint, &data, encoded_len))
1402                 goto err;
1403         if (EC_POINT_point2oct(group, pubkey, POINT_CONVERSION_UNCOMPRESSED,
1404             data, encoded_len, bn_ctx) == 0) {
1405                 SSLerror(s, ERR_R_ECDH_LIB);
1406                 goto err;
1407         }
1408         if (!CBB_flush(cbb))
1409                 goto err;
1410
1411         BN_CTX_free(bn_ctx);
1412
1413         return (1);
1414
1415  f_err:
1416         ssl3_send_alert(s, SSL3_AL_FATAL, al);
1417  err:
1418         BN_CTX_free(bn_ctx);
1419
1420         return (-1);
1421 }
1422
1423 static int
1424 ssl3_send_server_kex_ecdhe_ecx(SSL *s, int nid, CBB *cbb)
1425 {
1426         uint8_t *public_key = NULL;
1427         int curve_id;
1428         CBB ecpoint;
1429         int ret = -1;
1430
1431         /* Generate an X25519 key pair. */
1432         if (S3I(s)->tmp.x25519 != NULL) {
1433                 SSLerror(s, ERR_R_INTERNAL_ERROR);
1434                 goto err;
1435         }
1436         if ((S3I(s)->tmp.x25519 = malloc(X25519_KEY_LENGTH)) == NULL)
1437                 goto err;
1438         if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL)
1439                 goto err;
1440         X25519_keypair(public_key, S3I(s)->tmp.x25519);
1441
1442         /* Serialize public key. */
1443         if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
1444                 SSLerror(s, SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
1445                 goto err;
1446         }
1447
1448         if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
1449                 goto err;
1450         if (!CBB_add_u16(cbb, curve_id))
1451                 goto err;
1452         if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
1453                 goto err;
1454         if (!CBB_add_bytes(&ecpoint, public_key, X25519_KEY_LENGTH))
1455                 goto err;
1456         if (!CBB_flush(cbb))
1457                 goto err;
1458
1459         ret = 1;
1460
1461  err:
1462         free(public_key);
1463
1464         return (ret);
1465 }
1466
1467 static int
1468 ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
1469 {
1470         int nid;
1471
1472         nid = tls1_get_shared_curve(s);
1473
1474         if (nid == NID_X25519)
1475                 return ssl3_send_server_kex_ecdhe_ecx(s, nid, cbb);
1476
1477         return ssl3_send_server_kex_ecdhe_ecp(s, nid, cbb);
1478 }
1479
1480 int
1481 ssl3_send_server_key_exchange(SSL *s)
1482 {
1483         CBB cbb, cbb_params, cbb_signature, server_kex;
1484         const struct ssl_sigalg *sigalg = NULL;
1485         unsigned char *signature = NULL;
1486         size_t signature_len = 0;
1487         unsigned char *params = NULL;
1488         size_t params_len;
1489         const EVP_MD *md = NULL;
1490         unsigned long type;
1491         EVP_MD_CTX md_ctx;
1492         EVP_PKEY_CTX *pctx;
1493         EVP_PKEY *pkey;
1494         int al;
1495
1496         memset(&cbb, 0, sizeof(cbb));
1497         memset(&cbb_params, 0, sizeof(cbb_params));
1498
1499         EVP_MD_CTX_init(&md_ctx);
1500
1501         if (S3I(s)->hs.state == SSL3_ST_SW_KEY_EXCH_A) {
1502
1503                 if (!ssl3_handshake_msg_start(s, &cbb, &server_kex,
1504                     SSL3_MT_SERVER_KEY_EXCHANGE))
1505                         goto err;
1506
1507                 if (!CBB_init(&cbb_params, 0))
1508                         goto err;
1509
1510                 type = S3I(s)->hs.new_cipher->algorithm_mkey;
1511                 if (type & SSL_kDHE) {
1512                         if (ssl3_send_server_kex_dhe(s, &cbb_params) != 1)
1513                                 goto err;
1514                 } else if (type & SSL_kECDHE) {
1515                         if (ssl3_send_server_kex_ecdhe(s, &cbb_params) != 1)
1516                                 goto err;
1517                 } else {
1518                         al = SSL_AD_HANDSHAKE_FAILURE;
1519                         SSLerror(s, SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
1520                         goto f_err;
1521                 }
1522
1523                 if (!CBB_finish(&cbb_params, &params, &params_len))
1524                         goto err;
1525
1526                 if (!CBB_add_bytes(&server_kex, params, params_len))
1527                         goto err;
1528
1529                 /* Add signature unless anonymous. */
1530                 if (!(S3I(s)->hs.new_cipher->algorithm_auth & SSL_aNULL)) {
1531                         if ((pkey = ssl_get_sign_pkey(s, S3I(s)->hs.new_cipher,
1532                             &md, &sigalg)) == NULL) {
1533                                 al = SSL_AD_DECODE_ERROR;
1534                                 goto f_err;
1535                         }
1536
1537                         /* Send signature algorithm. */
1538                         if (SSL_USE_SIGALGS(s)) {
1539                                 if (!CBB_add_u16(&server_kex, sigalg->value)) {
1540                                         al = SSL_AD_INTERNAL_ERROR;
1541                                         SSLerror(s, ERR_R_INTERNAL_ERROR);
1542                                         goto f_err;
1543                                 }
1544                         }
1545
1546                         if (!EVP_DigestSignInit(&md_ctx, &pctx, md, NULL, pkey)) {
1547                                 SSLerror(s, ERR_R_EVP_LIB);
1548                                 goto err;
1549                         }
1550                         if ((sigalg->flags & SIGALG_FLAG_RSA_PSS) &&
1551                             (!EVP_PKEY_CTX_set_rsa_padding(pctx,
1552                             RSA_PKCS1_PSS_PADDING) ||
1553                             !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1))) {
1554                                 SSLerror(s, ERR_R_EVP_LIB);
1555                                 goto err;
1556                         }
1557                         if (!EVP_DigestSignUpdate(&md_ctx, s->s3->client_random,
1558                             SSL3_RANDOM_SIZE)) {
1559                                 SSLerror(s, ERR_R_EVP_LIB);
1560                                 goto err;
1561                         }
1562                         if (!EVP_DigestSignUpdate(&md_ctx, s->s3->server_random,
1563                             SSL3_RANDOM_SIZE)) {
1564                                 SSLerror(s, ERR_R_EVP_LIB);
1565                                 goto err;
1566                         }
1567                         if (!EVP_DigestSignUpdate(&md_ctx, params, params_len)) {
1568                                 SSLerror(s, ERR_R_EVP_LIB);
1569                                 goto err;
1570                         }
1571                         if (!EVP_DigestSignFinal(&md_ctx, NULL, &signature_len) ||
1572                             !signature_len) {
1573                                 SSLerror(s, ERR_R_EVP_LIB);
1574                                 goto err;
1575                         }
1576                         if ((signature = calloc(1, signature_len)) == NULL) {
1577                                 SSLerror(s, ERR_R_MALLOC_FAILURE);
1578                                 goto err;
1579                         }
1580                         if (!EVP_DigestSignFinal(&md_ctx, signature, &signature_len)) {
1581                                 SSLerror(s, ERR_R_EVP_LIB);
1582                                 goto err;
1583                         }
1584
1585                         if (!CBB_add_u16_length_prefixed(&server_kex,
1586                             &cbb_signature))
1587                                 goto err;
1588                         if (!CBB_add_bytes(&cbb_signature, signature,
1589                             signature_len))
1590                                 goto err;
1591                 }
1592
1593                 if (!ssl3_handshake_msg_finish(s, &cbb))
1594                         goto err;
1595
1596                 S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_B;
1597         }
1598
1599         EVP_MD_CTX_cleanup(&md_ctx);
1600         free(params);
1601         free(signature);
1602
1603         return (ssl3_handshake_write(s));
1604
1605  f_err:
1606         ssl3_send_alert(s, SSL3_AL_FATAL, al);
1607  err:
1608         CBB_cleanup(&cbb_params);
1609         CBB_cleanup(&cbb);
1610         EVP_MD_CTX_cleanup(&md_ctx);
1611         free(params);
1612         free(signature);
1613
1614         return (-1);
1615 }
1616
1617 int
1618 ssl3_send_certificate_request(SSL *s)
1619 {
1620         CBB cbb, cert_request, cert_types, sigalgs, cert_auth, dn;
1621         STACK_OF(X509_NAME) *sk = NULL;
1622         X509_NAME *name;
1623         int i;
1624
1625         /*
1626          * Certificate Request - RFC 5246 section 7.4.4.
1627          */
1628
1629         memset(&cbb, 0, sizeof(cbb));
1630
1631         if (S3I(s)->hs.state == SSL3_ST_SW_CERT_REQ_A) {
1632                 if (!ssl3_handshake_msg_start(s, &cbb, &cert_request,
1633                     SSL3_MT_CERTIFICATE_REQUEST))
1634                         goto err;
1635
1636                 if (!CBB_add_u8_length_prefixed(&cert_request, &cert_types))
1637                         goto err;
1638                 if (!ssl3_get_req_cert_types(s, &cert_types))
1639                         goto err;
1640
1641                 if (SSL_USE_SIGALGS(s)) {
1642                         if (!CBB_add_u16_length_prefixed(&cert_request, &sigalgs))
1643                                 goto err;
1644                         if (!ssl_sigalgs_build(&sigalgs, tls12_sigalgs, tls12_sigalgs_len))
1645                                 goto err;
1646                 }
1647
1648                 if (!CBB_add_u16_length_prefixed(&cert_request, &cert_auth))
1649                         goto err;
1650
1651                 sk = SSL_get_client_CA_list(s);
1652                 for (i = 0; i < sk_X509_NAME_num(sk); i++) {
1653                         unsigned char *name_data;
1654                         size_t name_len;
1655
1656                         name = sk_X509_NAME_value(sk, i);
1657                         name_len = i2d_X509_NAME(name, NULL);
1658
1659                         if (!CBB_add_u16_length_prefixed(&cert_auth, &dn))
1660                                 goto err;
1661                         if (!CBB_add_space(&dn, &name_data, name_len))
1662                                 goto err;
1663                         if (i2d_X509_NAME(name, &name_data) != name_len)
1664                                 goto err;
1665                 }
1666
1667                 if (!ssl3_handshake_msg_finish(s, &cbb))
1668                         goto err;
1669
1670                 S3I(s)->hs.state = SSL3_ST_SW_CERT_REQ_B;
1671         }
1672
1673         /* SSL3_ST_SW_CERT_REQ_B */
1674         return (ssl3_handshake_write(s));
1675
1676  err:
1677         CBB_cleanup(&cbb);
1678
1679         return (-1);
1680 }
1681
1682 static int
1683 ssl3_get_client_kex_rsa(SSL *s, CBS *cbs)
1684 {
1685         unsigned char fakekey[SSL_MAX_MASTER_KEY_LENGTH];
1686         unsigned char *pms = NULL;
1687         unsigned char *p;
1688         size_t pms_len = 0;
1689         EVP_PKEY *pkey = NULL;
1690         RSA *rsa = NULL;
1691         CBS enc_pms;
1692         int decrypt_len;
1693         int al = -1;
1694
1695         arc4random_buf(fakekey, sizeof(fakekey));
1696         fakekey[0] = s->client_version >> 8;
1697         fakekey[1] = s->client_version & 0xff;
1698
1699         pkey = s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey;
1700         if ((pkey == NULL) || (pkey->type != EVP_PKEY_RSA) ||
1701             (pkey->pkey.rsa == NULL)) {
1702                 al = SSL_AD_HANDSHAKE_FAILURE;
1703                 SSLerror(s, SSL_R_MISSING_RSA_CERTIFICATE);
1704                 goto f_err;
1705         }
1706         rsa = pkey->pkey.rsa;
1707
1708         pms_len = RSA_size(rsa);
1709         if (pms_len < SSL_MAX_MASTER_KEY_LENGTH)
1710                 goto err;
1711         if ((pms = malloc(pms_len)) == NULL)
1712                 goto err;
1713         p = pms;
1714
1715         if (!CBS_get_u16_length_prefixed(cbs, &enc_pms))
1716                 goto truncated;
1717         if (CBS_len(cbs) != 0 || CBS_len(&enc_pms) != RSA_size(rsa)) {
1718                 SSLerror(s, SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG);
1719                 goto err;
1720         }
1721
1722         decrypt_len = RSA_private_decrypt(CBS_len(&enc_pms), CBS_data(&enc_pms),
1723             pms, rsa, RSA_PKCS1_PADDING);
1724
1725         ERR_clear_error();
1726
1727         if (decrypt_len != SSL_MAX_MASTER_KEY_LENGTH) {
1728                 al = SSL_AD_DECODE_ERROR;
1729                 /* SSLerror(s, SSL_R_BAD_RSA_DECRYPT); */
1730         }
1731
1732         if ((al == -1) && !((pms[0] == (s->client_version >> 8)) &&
1733             (pms[1] == (s->client_version & 0xff)))) {
1734                 /*
1735                  * The premaster secret must contain the same version number
1736                  * as the ClientHello to detect version rollback attacks
1737                  * (strangely, the protocol does not offer such protection for
1738                  * DH ciphersuites).
1739                  *
1740                  * The Klima-Pokorny-Rosa extension of Bleichenbacher's attack
1741                  * (http://eprint.iacr.org/2003/052/) exploits the version
1742                  * number check as a "bad version oracle" -- an alert would
1743                  * reveal that the plaintext corresponding to some ciphertext
1744                  * made up by the adversary is properly formatted except that
1745                  * the version number is wrong. To avoid such attacks, we should
1746                  * treat this just like any other decryption error.
1747                  */
1748                 al = SSL_AD_DECODE_ERROR;
1749                 /* SSLerror(s, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); */
1750         }
1751
1752         if (al != -1) {
1753                 /*
1754                  * Some decryption failure -- use random value instead
1755                  * as countermeasure against Bleichenbacher's attack
1756                  * on PKCS #1 v1.5 RSA padding (see RFC 2246,
1757                  * section 7.4.7.1).
1758                  */
1759                 p = fakekey;
1760         }
1761
1762         s->session->master_key_length =
1763             tls1_generate_master_secret(s,
1764                 s->session->master_key, p, SSL_MAX_MASTER_KEY_LENGTH);
1765
1766         freezero(pms, pms_len);
1767
1768         return (1);
1769
1770  truncated:
1771         al = SSL_AD_DECODE_ERROR;
1772         SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1773  f_err:
1774         ssl3_send_alert(s, SSL3_AL_FATAL, al);
1775  err:
1776         freezero(pms, pms_len);
1777
1778         return (-1);
1779 }
1780
1781 static int
1782 ssl3_get_client_kex_dhe(SSL *s, CBS *cbs)
1783 {
1784         int key_size = 0, key_len, al;
1785         unsigned char *key = NULL;
1786         BIGNUM *bn = NULL;
1787         CBS dh_Yc;
1788         DH *dh;
1789
1790         if (!CBS_get_u16_length_prefixed(cbs, &dh_Yc))
1791                 goto truncated;
1792         if (CBS_len(cbs) != 0)
1793                 goto truncated;
1794
1795         if (S3I(s)->tmp.dh == NULL) {
1796                 al = SSL_AD_HANDSHAKE_FAILURE;
1797                 SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
1798                 goto f_err;
1799         }
1800         dh = S3I(s)->tmp.dh;
1801
1802         if ((bn = BN_bin2bn(CBS_data(&dh_Yc), CBS_len(&dh_Yc), NULL)) == NULL) {
1803                 SSLerror(s, SSL_R_BN_LIB);
1804                 goto err;
1805         }
1806
1807         if ((key_size = DH_size(dh)) <= 0) {
1808                 SSLerror(s, ERR_R_DH_LIB);
1809                 goto err;
1810         }
1811         if ((key = malloc(key_size)) == NULL) {
1812                 SSLerror(s, ERR_R_MALLOC_FAILURE);
1813                 goto err;
1814         }
1815         if ((key_len = DH_compute_key(key, bn, dh)) <= 0) {
1816                 SSLerror(s, ERR_R_DH_LIB);
1817                 goto err;
1818         }
1819
1820         s->session->master_key_length = tls1_generate_master_secret(s,
1821             s->session->master_key, key, key_len);
1822
1823         DH_free(S3I(s)->tmp.dh);
1824         S3I(s)->tmp.dh = NULL;
1825
1826         freezero(key, key_size);
1827         BN_clear_free(bn);
1828
1829         return (1);
1830
1831  truncated:
1832         al = SSL_AD_DECODE_ERROR;
1833         SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1834  f_err:
1835         ssl3_send_alert(s, SSL3_AL_FATAL, al);
1836  err:
1837         freezero(key, key_size);
1838         BN_clear_free(bn);
1839
1840         return (-1);
1841 }
1842
1843 static int
1844 ssl3_get_client_kex_ecdhe_ecp(SSL *s, CBS *cbs)
1845 {
1846         unsigned char *key = NULL;
1847         int key_size = 0, key_len;
1848         EC_POINT *point = NULL;
1849         BN_CTX *bn_ctx = NULL;
1850         const EC_GROUP *group;
1851         EC_KEY *ecdh;
1852         CBS public;
1853         int ret = -1;
1854
1855         if (!CBS_get_u8_length_prefixed(cbs, &public))
1856                 goto err;
1857         if (CBS_len(cbs) != 0)
1858                 goto err;
1859
1860         /*
1861          * Use the ephemeral values we saved when generating the
1862          * ServerKeyExchange message.
1863          */
1864         if ((ecdh = S3I(s)->tmp.ecdh) == NULL) {
1865                 SSLerror(s, ERR_R_INTERNAL_ERROR);
1866                 goto err;
1867         }
1868         group = EC_KEY_get0_group(ecdh);
1869
1870         /*
1871          * Get client's public key from encoded point in the ClientKeyExchange
1872          * message.
1873          */
1874         if ((bn_ctx = BN_CTX_new()) == NULL) {
1875                 SSLerror(s, ERR_R_MALLOC_FAILURE);
1876                 goto err;
1877         }
1878         if ((point = EC_POINT_new(group)) == NULL) {
1879                 SSLerror(s, ERR_R_MALLOC_FAILURE);
1880                 goto err;
1881         }
1882         if (EC_POINT_oct2point(group, point, CBS_data(&public),
1883             CBS_len(&public), bn_ctx) == 0) {
1884                 SSLerror(s, ERR_R_EC_LIB);
1885                 goto err;
1886         }
1887
1888         /* Compute the shared pre-master secret */
1889         if ((key_size = ECDH_size(ecdh)) <= 0) {
1890                 SSLerror(s, ERR_R_ECDH_LIB);
1891                 goto err;
1892         }
1893         if ((key = malloc(key_size)) == NULL) {
1894                 SSLerror(s, ERR_R_MALLOC_FAILURE);
1895                 goto err;
1896         }
1897         if ((key_len = ECDH_compute_key(key, key_size, point, ecdh,
1898             NULL)) <= 0) {
1899                 SSLerror(s, ERR_R_ECDH_LIB);
1900                 goto err;
1901         }
1902
1903         /* Compute the master secret */
1904         s->session->master_key_length = tls1_generate_master_secret(s,
1905             s->session->master_key, key, key_len);
1906
1907         EC_KEY_free(S3I(s)->tmp.ecdh);
1908         S3I(s)->tmp.ecdh = NULL;
1909
1910         ret = 1;
1911
1912  err:
1913         freezero(key, key_size);
1914         EC_POINT_free(point);
1915         BN_CTX_free(bn_ctx);
1916
1917         return (ret);
1918 }
1919
1920 static int
1921 ssl3_get_client_kex_ecdhe_ecx(SSL *s, CBS *cbs)
1922 {
1923         uint8_t *shared_key = NULL;
1924         CBS ecpoint;
1925         int ret = -1;
1926
1927         if (!CBS_get_u8_length_prefixed(cbs, &ecpoint))
1928                 goto err;
1929         if (CBS_len(cbs) != 0)
1930                 goto err;
1931         if (CBS_len(&ecpoint) != X25519_KEY_LENGTH)
1932                 goto err;
1933
1934         if ((shared_key = malloc(X25519_KEY_LENGTH)) == NULL)
1935                 goto err;
1936         if (!X25519(shared_key, S3I(s)->tmp.x25519, CBS_data(&ecpoint)))
1937                 goto err;
1938
1939         freezero(S3I(s)->tmp.x25519, X25519_KEY_LENGTH);
1940         S3I(s)->tmp.x25519 = NULL;
1941
1942         s->session->master_key_length =
1943             tls1_generate_master_secret(
1944                 s, s->session->master_key, shared_key, X25519_KEY_LENGTH);
1945
1946         ret = 1;
1947
1948  err:
1949         freezero(shared_key, X25519_KEY_LENGTH);
1950
1951         return (ret);
1952 }
1953
1954 static int
1955 ssl3_get_client_kex_ecdhe(SSL *s, CBS *cbs)
1956 {
1957         if (S3I(s)->tmp.x25519 != NULL)
1958                 return ssl3_get_client_kex_ecdhe_ecx(s, cbs);
1959
1960         return ssl3_get_client_kex_ecdhe_ecp(s, cbs);
1961 }
1962
1963 static int
1964 ssl3_get_client_kex_gost(SSL *s, CBS *cbs)
1965 {
1966         EVP_PKEY_CTX *pkey_ctx;
1967         EVP_PKEY *client_pub_pkey = NULL, *pk = NULL;
1968         unsigned char premaster_secret[32];
1969         unsigned long alg_a;
1970         size_t outlen = 32;
1971         CBS gostblob;
1972         int al;
1973         int ret = 0;
1974
1975         /* Get our certificate private key*/
1976         alg_a = S3I(s)->hs.new_cipher->algorithm_auth;
1977         if (alg_a & SSL_aGOST01)
1978                 pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
1979
1980         if ((pkey_ctx = EVP_PKEY_CTX_new(pk, NULL)) == NULL)
1981                 goto err;
1982         if (EVP_PKEY_decrypt_init(pkey_ctx) <= 0)
1983                 goto gerr;
1984
1985         /*
1986          * If client certificate is present and is of the same type,
1987          * maybe use it for key exchange.
1988          * Don't mind errors from EVP_PKEY_derive_set_peer, because
1989          * it is completely valid to use a client certificate for
1990          * authorization only.
1991          */
1992         if ((client_pub_pkey = X509_get_pubkey(s->session->peer)) != NULL) {
1993                 if (EVP_PKEY_derive_set_peer(pkey_ctx,
1994                     client_pub_pkey) <= 0)
1995                         ERR_clear_error();
1996         }
1997
1998         /* Decrypt session key */
1999         if (!CBS_get_asn1(cbs, &gostblob, CBS_ASN1_SEQUENCE))
2000                 goto truncated;
2001         if (CBS_len(cbs) != 0)
2002                 goto truncated;
2003         if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen,
2004             CBS_data(&gostblob), CBS_len(&gostblob)) <= 0) {
2005                 SSLerror(s, SSL_R_DECRYPTION_FAILED);
2006                 goto gerr;
2007         }
2008
2009         /* Generate master secret */
2010         s->session->master_key_length =
2011             tls1_generate_master_secret(
2012                 s, s->session->master_key, premaster_secret, 32);
2013
2014         /* Check if pubkey from client certificate was used */
2015         if (EVP_PKEY_CTX_ctrl(pkey_ctx, -1, -1,
2016             EVP_PKEY_CTRL_PEER_KEY, 2, NULL) > 0)
2017                 ret = 2;
2018         else
2019                 ret = 1;
2020  gerr:
2021         EVP_PKEY_free(client_pub_pkey);
2022         EVP_PKEY_CTX_free(pkey_ctx);
2023         if (ret)
2024                 return (ret);
2025         else
2026                 goto err;
2027
2028  truncated:
2029         al = SSL_AD_DECODE_ERROR;
2030         SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2031         ssl3_send_alert(s, SSL3_AL_FATAL, al);
2032  err:
2033         return (-1);
2034 }
2035
2036 int
2037 ssl3_get_client_key_exchange(SSL *s)
2038 {
2039         unsigned long alg_k;
2040         int al, ok;
2041         CBS cbs;
2042         long n;
2043
2044         /* 2048 maxlen is a guess.  How long a key does that permit? */
2045         n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_KEY_EXCH_A,
2046             SSL3_ST_SR_KEY_EXCH_B, SSL3_MT_CLIENT_KEY_EXCHANGE, 2048, &ok);
2047         if (!ok)
2048                 return ((int)n);
2049
2050         if (n < 0)
2051                 goto err;
2052
2053         CBS_init(&cbs, s->internal->init_msg, n);
2054
2055         alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
2056
2057         if (alg_k & SSL_kRSA) {
2058                 if (ssl3_get_client_kex_rsa(s, &cbs) != 1)
2059                         goto err;
2060         } else if (alg_k & SSL_kDHE) {
2061                 if (ssl3_get_client_kex_dhe(s, &cbs) != 1)
2062                         goto err;
2063         } else if (alg_k & SSL_kECDHE) {
2064                 if (ssl3_get_client_kex_ecdhe(s, &cbs) != 1)
2065                         goto err;
2066         } else if (alg_k & SSL_kGOST) {
2067                 if (ssl3_get_client_kex_gost(s, &cbs) != 1)
2068                         goto err;
2069         } else {
2070                 al = SSL_AD_HANDSHAKE_FAILURE;
2071                 SSLerror(s, SSL_R_UNKNOWN_CIPHER_TYPE);
2072                 goto f_err;
2073         }
2074
2075         if (CBS_len(&cbs) != 0) {
2076                 al = SSL_AD_DECODE_ERROR;
2077                 SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2078                 goto f_err;
2079         }
2080
2081         return (1);
2082
2083  f_err:
2084         ssl3_send_alert(s, SSL3_AL_FATAL, al);
2085  err:
2086         return (-1);
2087 }
2088
2089 int
2090 ssl3_get_cert_verify(SSL *s)
2091 {
2092         CBS cbs, signature;
2093         const struct ssl_sigalg *sigalg = NULL;
2094         const EVP_MD *md = NULL;
2095         EVP_PKEY *pkey = NULL;
2096         X509 *peer = NULL;
2097         EVP_MD_CTX mctx;
2098         int al, ok, verify;
2099         const unsigned char *hdata;
2100         size_t hdatalen;
2101         int type = 0;
2102         int ret = 0;
2103         long n;
2104
2105         EVP_MD_CTX_init(&mctx);
2106
2107         n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_CERT_VRFY_A,
2108             SSL3_ST_SR_CERT_VRFY_B, -1, SSL3_RT_MAX_PLAIN_LENGTH, &ok);
2109         if (!ok)
2110                 return ((int)n);
2111
2112         if (n < 0)
2113                 goto err;
2114
2115         CBS_init(&cbs, s->internal->init_msg, n);
2116
2117         if (s->session->peer != NULL) {
2118                 peer = s->session->peer;
2119                 pkey = X509_get_pubkey(peer);
2120                 type = X509_certificate_type(peer, pkey);
2121         }
2122
2123         if (S3I(s)->tmp.message_type != SSL3_MT_CERTIFICATE_VERIFY) {
2124                 S3I(s)->tmp.reuse_message = 1;
2125                 if (peer != NULL) {
2126                         al = SSL_AD_UNEXPECTED_MESSAGE;
2127                         SSLerror(s, SSL_R_MISSING_VERIFY_MESSAGE);
2128                         goto f_err;
2129                 }
2130                 ret = 1;
2131                 goto end;
2132         }
2133
2134         if (peer == NULL) {
2135                 SSLerror(s, SSL_R_NO_CLIENT_CERT_RECEIVED);
2136                 al = SSL_AD_UNEXPECTED_MESSAGE;
2137                 goto f_err;
2138         }
2139
2140         if (!(type & EVP_PKT_SIGN)) {
2141                 SSLerror(s, SSL_R_SIGNATURE_FOR_NON_SIGNING_CERTIFICATE);
2142                 al = SSL_AD_ILLEGAL_PARAMETER;
2143                 goto f_err;
2144         }
2145
2146         if (S3I(s)->change_cipher_spec) {
2147                 SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
2148                 al = SSL_AD_UNEXPECTED_MESSAGE;
2149                 goto f_err;
2150         }
2151
2152         if (!SSL_USE_SIGALGS(s)) {
2153                 if (!CBS_get_u16_length_prefixed(&cbs, &signature))
2154                         goto err;
2155                 if (CBS_len(&signature) > EVP_PKEY_size(pkey)) {
2156                         SSLerror(s, SSL_R_WRONG_SIGNATURE_SIZE);
2157                         al = SSL_AD_DECODE_ERROR;
2158                         goto f_err;
2159                 }
2160                 if (CBS_len(&cbs) != 0) {
2161                         al = SSL_AD_DECODE_ERROR;
2162                         SSLerror(s, SSL_R_EXTRA_DATA_IN_MESSAGE);
2163                         goto f_err;
2164                 }
2165         }
2166
2167         if (SSL_USE_SIGALGS(s)) {
2168                 EVP_PKEY_CTX *pctx;
2169                 uint16_t sigalg_value;
2170
2171                 if (!CBS_get_u16(&cbs, &sigalg_value))
2172                         goto truncated;
2173                 if ((sigalg = ssl_sigalg(sigalg_value, tls12_sigalgs,
2174                     tls12_sigalgs_len)) == NULL ||
2175                     (md = sigalg->md()) == NULL) {
2176                         SSLerror(s, SSL_R_UNKNOWN_DIGEST);
2177                         al = SSL_AD_DECODE_ERROR;
2178                         goto f_err;
2179                 }
2180                 if (!ssl_sigalg_pkey_ok(sigalg, pkey, 0)) {
2181                         SSLerror(s, SSL_R_WRONG_SIGNATURE_TYPE);
2182                         al = SSL_AD_DECODE_ERROR;
2183                         goto f_err;
2184                 }
2185
2186                 if (!CBS_get_u16_length_prefixed(&cbs, &signature))
2187                         goto err;
2188                 if (CBS_len(&signature) > EVP_PKEY_size(pkey)) {
2189                         SSLerror(s, SSL_R_WRONG_SIGNATURE_SIZE);
2190                         al = SSL_AD_DECODE_ERROR;
2191                         goto f_err;
2192                 }
2193                 if (CBS_len(&cbs) != 0) {
2194                         al = SSL_AD_DECODE_ERROR;
2195                         SSLerror(s, SSL_R_EXTRA_DATA_IN_MESSAGE);
2196                         goto f_err;
2197                 }
2198
2199                 if (!tls1_transcript_data(s, &hdata, &hdatalen)) {
2200                         SSLerror(s, ERR_R_INTERNAL_ERROR);
2201                         al = SSL_AD_INTERNAL_ERROR;
2202                         goto f_err;
2203                 }
2204                 if (!EVP_DigestVerifyInit(&mctx, &pctx, md, NULL, pkey)) {
2205                         SSLerror(s, ERR_R_EVP_LIB);
2206                         al = SSL_AD_INTERNAL_ERROR;
2207                         goto f_err;
2208                 }
2209                 if ((sigalg->flags & SIGALG_FLAG_RSA_PSS) &&
2210                     (!EVP_PKEY_CTX_set_rsa_padding
2211                     (pctx, RSA_PKCS1_PSS_PADDING) ||
2212                     !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1))) {
2213                         al = SSL_AD_INTERNAL_ERROR;
2214                         goto f_err;
2215                 }
2216                 if (!EVP_DigestVerifyUpdate(&mctx, hdata, hdatalen)) {
2217                         SSLerror(s, ERR_R_EVP_LIB);
2218                         al = SSL_AD_INTERNAL_ERROR;
2219                         goto f_err;
2220                 }
2221                 if (EVP_DigestVerifyFinal(&mctx, CBS_data(&signature),
2222                     CBS_len(&signature)) <= 0) {
2223                         al = SSL_AD_DECRYPT_ERROR;
2224                         SSLerror(s, SSL_R_BAD_SIGNATURE);
2225                         goto f_err;
2226                 }
2227         } else if (pkey->type == EVP_PKEY_RSA) {
2228                 verify = RSA_verify(NID_md5_sha1, S3I(s)->tmp.cert_verify_md,
2229                     MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH, CBS_data(&signature),
2230                     CBS_len(&signature), pkey->pkey.rsa);
2231                 if (verify < 0) {
2232                         al = SSL_AD_DECRYPT_ERROR;
2233                         SSLerror(s, SSL_R_BAD_RSA_DECRYPT);
2234                         goto f_err;
2235                 }
2236                 if (verify == 0) {
2237                         al = SSL_AD_DECRYPT_ERROR;
2238                         SSLerror(s, SSL_R_BAD_RSA_SIGNATURE);
2239                         goto f_err;
2240                 }
2241         } else if (pkey->type == EVP_PKEY_EC) {
2242                 verify = ECDSA_verify(pkey->save_type,
2243                     &(S3I(s)->tmp.cert_verify_md[MD5_DIGEST_LENGTH]),
2244                     SHA_DIGEST_LENGTH, CBS_data(&signature),
2245                     CBS_len(&signature), pkey->pkey.ec);
2246                 if (verify <= 0) {
2247                         al = SSL_AD_DECRYPT_ERROR;
2248                         SSLerror(s, SSL_R_BAD_ECDSA_SIGNATURE);
2249                         goto f_err;
2250                 }
2251 #ifndef OPENSSL_NO_GOST
2252         } else if (pkey->type == NID_id_GostR3410_94 ||
2253             pkey->type == NID_id_GostR3410_2001) {
2254                 unsigned char sigbuf[128];
2255                 unsigned int siglen = sizeof(sigbuf);
2256                 EVP_PKEY_CTX *pctx;
2257                 int nid;
2258
2259                 if (!tls1_transcript_data(s, &hdata, &hdatalen)) {
2260                         SSLerror(s, ERR_R_INTERNAL_ERROR);
2261                         al = SSL_AD_INTERNAL_ERROR;
2262                         goto f_err;
2263                 }
2264                 if (!EVP_PKEY_get_default_digest_nid(pkey, &nid) ||
2265                     !(md = EVP_get_digestbynid(nid))) {
2266                         SSLerror(s, ERR_R_EVP_LIB);
2267                         al = SSL_AD_INTERNAL_ERROR;
2268                         goto f_err;
2269                 }
2270                 if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL) {
2271                         SSLerror(s, ERR_R_EVP_LIB);
2272                         al = SSL_AD_INTERNAL_ERROR;
2273                         goto f_err;
2274                 }
2275                 if (!EVP_DigestInit_ex(&mctx, md, NULL) ||
2276                     !EVP_DigestUpdate(&mctx, hdata, hdatalen) ||
2277                     !EVP_DigestFinal(&mctx, sigbuf, &siglen) ||
2278                     (EVP_PKEY_verify_init(pctx) <= 0) ||
2279                     (EVP_PKEY_CTX_set_signature_md(pctx, md) <= 0) ||
2280                     (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_VERIFY,
2281                     EVP_PKEY_CTRL_GOST_SIG_FORMAT,
2282                     GOST_SIG_FORMAT_RS_LE, NULL) <= 0)) {
2283                         SSLerror(s, ERR_R_EVP_LIB);
2284                         al = SSL_AD_INTERNAL_ERROR;
2285                         EVP_PKEY_CTX_free(pctx);
2286                         goto f_err;
2287                 }
2288                 if (EVP_PKEY_verify(pctx, CBS_data(&signature),
2289                     CBS_len(&signature), sigbuf, siglen) <= 0) {
2290                         al = SSL_AD_DECRYPT_ERROR;
2291                         SSLerror(s, SSL_R_BAD_SIGNATURE);
2292                         EVP_PKEY_CTX_free(pctx);
2293                         goto f_err;
2294                 }
2295
2296                 EVP_PKEY_CTX_free(pctx);
2297 #endif
2298         } else {
2299                 SSLerror(s, ERR_R_INTERNAL_ERROR);
2300                 al = SSL_AD_UNSUPPORTED_CERTIFICATE;
2301                 goto f_err;
2302         }
2303
2304         ret = 1;
2305         if (0) {
2306  truncated:
2307                 al = SSL_AD_DECODE_ERROR;
2308                 SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2309  f_err:
2310                 ssl3_send_alert(s, SSL3_AL_FATAL, al);
2311         }
2312  end:
2313         tls1_transcript_free(s);
2314  err:
2315         EVP_MD_CTX_cleanup(&mctx);
2316         EVP_PKEY_free(pkey);
2317         return (ret);
2318 }
2319
2320 int
2321 ssl3_get_client_certificate(SSL *s)
2322 {
2323         CBS cbs, client_certs;
2324         int i, ok, al, ret = -1;
2325         X509 *x = NULL;
2326         long n;
2327         const unsigned char *q;
2328         STACK_OF(X509) *sk = NULL;
2329
2330         n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_CERT_A, SSL3_ST_SR_CERT_B,
2331             -1, s->internal->max_cert_list, &ok);
2332
2333         if (!ok)
2334                 return ((int)n);
2335
2336         if (S3I(s)->tmp.message_type == SSL3_MT_CLIENT_KEY_EXCHANGE) {
2337                 if ((s->verify_mode & SSL_VERIFY_PEER) &&
2338                     (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
2339                         SSLerror(s, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
2340                         al = SSL_AD_HANDSHAKE_FAILURE;
2341                         goto f_err;
2342                 }
2343                 /*
2344                  * If tls asked for a client cert,
2345                  * the client must return a 0 list.
2346                  */
2347                 if (S3I(s)->tmp.cert_request) {
2348                         SSLerror(s, SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST
2349                             );
2350                         al = SSL_AD_UNEXPECTED_MESSAGE;
2351                         goto f_err;
2352                 }
2353                 S3I(s)->tmp.reuse_message = 1;
2354                 return (1);
2355         }
2356
2357         if (S3I(s)->tmp.message_type != SSL3_MT_CERTIFICATE) {
2358                 al = SSL_AD_UNEXPECTED_MESSAGE;
2359                 SSLerror(s, SSL_R_WRONG_MESSAGE_TYPE);
2360                 goto f_err;
2361         }
2362
2363         if (n < 0)
2364                 goto truncated;
2365
2366         CBS_init(&cbs, s->internal->init_msg, n);
2367
2368         if ((sk = sk_X509_new_null()) == NULL) {
2369                 SSLerror(s, ERR_R_MALLOC_FAILURE);
2370                 goto err;
2371         }
2372
2373         if (!CBS_get_u24_length_prefixed(&cbs, &client_certs) ||
2374             CBS_len(&cbs) != 0)
2375                 goto truncated;
2376
2377         while (CBS_len(&client_certs) > 0) {
2378                 CBS cert;
2379
2380                 if (!CBS_get_u24_length_prefixed(&client_certs, &cert)) {
2381                         al = SSL_AD_DECODE_ERROR;
2382                         SSLerror(s, SSL_R_CERT_LENGTH_MISMATCH);
2383                         goto f_err;
2384                 }
2385
2386                 q = CBS_data(&cert);
2387                 x = d2i_X509(NULL, &q, CBS_len(&cert));
2388                 if (x == NULL) {
2389                         SSLerror(s, ERR_R_ASN1_LIB);
2390                         goto err;
2391                 }
2392                 if (q != CBS_data(&cert) + CBS_len(&cert)) {
2393                         al = SSL_AD_DECODE_ERROR;
2394                         SSLerror(s, SSL_R_CERT_LENGTH_MISMATCH);
2395                         goto f_err;
2396                 }
2397                 if (!sk_X509_push(sk, x)) {
2398                         SSLerror(s, ERR_R_MALLOC_FAILURE);
2399                         goto err;
2400                 }
2401                 x = NULL;
2402         }
2403
2404         if (sk_X509_num(sk) <= 0) {
2405                 /*
2406                  * TLS does not mind 0 certs returned.
2407                  * Fail for TLS only if we required a certificate.
2408                  */
2409                 if ((s->verify_mode & SSL_VERIFY_PEER) &&
2410                     (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
2411                         SSLerror(s, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
2412                         al = SSL_AD_HANDSHAKE_FAILURE;
2413                         goto f_err;
2414                 }
2415                 /* No client certificate so free transcript. */
2416                 tls1_transcript_free(s);
2417         } else {
2418                 i = ssl_verify_cert_chain(s, sk);
2419                 if (i <= 0) {
2420                         al = ssl_verify_alarm_type(s->verify_result);
2421                         SSLerror(s, SSL_R_NO_CERTIFICATE_RETURNED);
2422                         goto f_err;
2423                 }
2424         }
2425
2426         X509_free(s->session->peer);
2427         s->session->peer = sk_X509_shift(sk);
2428         s->session->verify_result = s->verify_result;
2429
2430         /*
2431          * With the current implementation, sess_cert will always be NULL
2432          * when we arrive here
2433          */
2434         if (SSI(s)->sess_cert == NULL) {
2435                 SSI(s)->sess_cert = ssl_sess_cert_new();
2436                 if (SSI(s)->sess_cert == NULL) {
2437                         SSLerror(s, ERR_R_MALLOC_FAILURE);
2438                         goto err;
2439                 }
2440         }
2441         sk_X509_pop_free(SSI(s)->sess_cert->cert_chain, X509_free);
2442         SSI(s)->sess_cert->cert_chain = sk;
2443
2444         /*
2445          * Inconsistency alert: cert_chain does *not* include the
2446          * peer's own certificate, while we do include it in s3_clnt.c
2447          */
2448
2449         sk = NULL;
2450
2451         ret = 1;
2452         if (0) {
2453 truncated:
2454                 al = SSL_AD_DECODE_ERROR;
2455                 SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2456 f_err:
2457                 ssl3_send_alert(s, SSL3_AL_FATAL, al);
2458         }
2459 err:
2460         X509_free(x);
2461         sk_X509_pop_free(sk, X509_free);
2462
2463         return (ret);
2464 }
2465
2466 int
2467 ssl3_send_server_certificate(SSL *s)
2468 {
2469         CBB cbb, server_cert;
2470         CERT_PKEY *cpk;
2471
2472         /*
2473          * Server Certificate - RFC 5246, section 7.4.2.
2474          */
2475
2476         memset(&cbb, 0, sizeof(cbb));
2477
2478         if (S3I(s)->hs.state == SSL3_ST_SW_CERT_A) {
2479                 if ((cpk = ssl_get_server_send_pkey(s)) == NULL) {
2480                         SSLerror(s, ERR_R_INTERNAL_ERROR);
2481                         return (0);
2482                 }
2483
2484                 if (!ssl3_handshake_msg_start(s, &cbb, &server_cert,
2485                     SSL3_MT_CERTIFICATE))
2486                         goto err;
2487                 if (!ssl3_output_cert_chain(s, &server_cert, cpk))
2488                         goto err;
2489                 if (!ssl3_handshake_msg_finish(s, &cbb))
2490                         goto err;
2491
2492                 S3I(s)->hs.state = SSL3_ST_SW_CERT_B;
2493         }
2494
2495         /* SSL3_ST_SW_CERT_B */
2496         return (ssl3_handshake_write(s));
2497
2498  err:
2499         CBB_cleanup(&cbb);
2500
2501         return (0);
2502 }
2503
2504 /* send a new session ticket (not necessarily for a new session) */
2505 int
2506 ssl3_send_newsession_ticket(SSL *s)
2507 {
2508         CBB cbb, session_ticket, ticket;
2509         SSL_CTX *tctx = s->initial_ctx;
2510         size_t enc_session_len, enc_session_max_len, hmac_len;
2511         size_t session_len = 0;
2512         unsigned char *enc_session = NULL, *session = NULL;
2513         unsigned char iv[EVP_MAX_IV_LENGTH];
2514         unsigned char key_name[16];
2515         unsigned char *hmac;
2516         unsigned int hlen;
2517         EVP_CIPHER_CTX ctx;
2518         HMAC_CTX hctx;
2519         int len;
2520
2521         /*
2522          * New Session Ticket - RFC 5077, section 3.3.
2523          */
2524
2525         EVP_CIPHER_CTX_init(&ctx);
2526         HMAC_CTX_init(&hctx);
2527
2528         memset(&cbb, 0, sizeof(cbb));
2529
2530         if (S3I(s)->hs.state == SSL3_ST_SW_SESSION_TICKET_A) {
2531                 if (!ssl3_handshake_msg_start(s, &cbb, &session_ticket,
2532                     SSL3_MT_NEWSESSION_TICKET))
2533                         goto err;
2534
2535                 if (!SSL_SESSION_ticket(s->session, &session, &session_len))
2536                         goto err;
2537                 if (session_len > 0xffff)
2538                         goto err;
2539
2540                 /*
2541                  * Initialize HMAC and cipher contexts. If callback is present
2542                  * it does all the work, otherwise use generated values from
2543                  * parent context.
2544                  */
2545                 if (tctx->internal->tlsext_ticket_key_cb != NULL) {
2546                         if (tctx->internal->tlsext_ticket_key_cb(s,
2547                             key_name, iv, &ctx, &hctx, 1) < 0) {
2548                                 EVP_CIPHER_CTX_cleanup(&ctx);
2549                                 goto err;
2550                         }
2551                 } else {
2552                         arc4random_buf(iv, 16);
2553                         EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL,
2554                             tctx->internal->tlsext_tick_aes_key, iv);
2555                         HMAC_Init_ex(&hctx, tctx->internal->tlsext_tick_hmac_key,
2556                             16, tlsext_tick_md(), NULL);
2557                         memcpy(key_name, tctx->internal->tlsext_tick_key_name, 16);
2558                 }
2559
2560                 /* Encrypt the session state. */
2561                 enc_session_max_len = session_len + EVP_MAX_BLOCK_LENGTH;
2562                 if ((enc_session = calloc(1, enc_session_max_len)) == NULL)
2563                         goto err;
2564                 enc_session_len = 0;
2565                 if (!EVP_EncryptUpdate(&ctx, enc_session, &len, session,
2566                     session_len))
2567                         goto err;
2568                 enc_session_len += len;
2569                 if (!EVP_EncryptFinal_ex(&ctx, enc_session + enc_session_len,
2570                     &len))
2571                         goto err;
2572                 enc_session_len += len;
2573
2574                 if (enc_session_len > enc_session_max_len)
2575                         goto err;
2576
2577                 /* Generate the HMAC. */
2578                 if (!HMAC_Update(&hctx, key_name, sizeof(key_name)))
2579                         goto err;
2580                 if (!HMAC_Update(&hctx, iv, EVP_CIPHER_CTX_iv_length(&ctx)))
2581                         goto err;
2582                 if (!HMAC_Update(&hctx, enc_session, enc_session_len))
2583                         goto err;
2584
2585                 if ((hmac_len = HMAC_size(&hctx)) <= 0)
2586                         goto err;
2587
2588                 /*
2589                  * Ticket lifetime hint (advisory only):
2590                  * We leave this unspecified for resumed session
2591                  * (for simplicity), and guess that tickets for new
2592                  * sessions will live as long as their sessions.
2593                  */
2594                 if (!CBB_add_u32(&session_ticket,
2595                     s->internal->hit ? 0 : s->session->timeout))
2596                         goto err;
2597
2598                 if (!CBB_add_u16_length_prefixed(&session_ticket, &ticket))
2599                         goto err;
2600                 if (!CBB_add_bytes(&ticket, key_name, sizeof(key_name)))
2601                         goto err;
2602                 if (!CBB_add_bytes(&ticket, iv, EVP_CIPHER_CTX_iv_length(&ctx)))
2603                         goto err;
2604                 if (!CBB_add_bytes(&ticket, enc_session, enc_session_len))
2605                         goto err;
2606                 if (!CBB_add_space(&ticket, &hmac, hmac_len))
2607                         goto err;
2608
2609                 if (!HMAC_Final(&hctx, hmac, &hlen))
2610                         goto err;
2611                 if (hlen != hmac_len)
2612                         goto err;
2613
2614                 if (!ssl3_handshake_msg_finish(s, &cbb))
2615                         goto err;
2616
2617                 S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_B;
2618         }
2619
2620         EVP_CIPHER_CTX_cleanup(&ctx);
2621         HMAC_CTX_cleanup(&hctx);
2622         freezero(session, session_len);
2623         free(enc_session);
2624
2625         /* SSL3_ST_SW_SESSION_TICKET_B */
2626         return (ssl3_handshake_write(s));
2627
2628  err:
2629         CBB_cleanup(&cbb);
2630         EVP_CIPHER_CTX_cleanup(&ctx);
2631         HMAC_CTX_cleanup(&hctx);
2632         freezero(session, session_len);
2633         free(enc_session);
2634
2635         return (-1);
2636 }
2637
2638 int
2639 ssl3_send_cert_status(SSL *s)
2640 {
2641         CBB cbb, certstatus, ocspresp;
2642
2643         memset(&cbb, 0, sizeof(cbb));
2644
2645         if (S3I(s)->hs.state == SSL3_ST_SW_CERT_STATUS_A) {
2646                 if (!ssl3_handshake_msg_start(s, &cbb, &certstatus,
2647                     SSL3_MT_CERTIFICATE_STATUS))
2648                         goto err;
2649                 if (!CBB_add_u8(&certstatus, s->tlsext_status_type))
2650                         goto err;
2651                 if (!CBB_add_u24_length_prefixed(&certstatus, &ocspresp))
2652                         goto err;
2653                 if (!CBB_add_bytes(&ocspresp, s->internal->tlsext_ocsp_resp,
2654                     s->internal->tlsext_ocsp_resplen))
2655                         goto err;
2656                 if (!ssl3_handshake_msg_finish(s, &cbb))
2657                         goto err;
2658
2659                 S3I(s)->hs.state = SSL3_ST_SW_CERT_STATUS_B;
2660         }
2661
2662         /* SSL3_ST_SW_CERT_STATUS_B */
2663         return (ssl3_handshake_write(s));
2664
2665  err:
2666         CBB_cleanup(&cbb);
2667
2668         return (-1);
2669 }