xref: /openbsd-src/lib/libssl/ssl_srvr.c (revision ae3cb403620ab940fbaabb3055fac045a63d56b7)
1 /* $OpenBSD: ssl_srvr.c,v 1.26 2017/10/12 15:52:50 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_tlsext.h"
170 
171 int
172 ssl3_accept(SSL *s)
173 {
174 	void (*cb)(const SSL *ssl, int type, int val) = NULL;
175 	unsigned long alg_k;
176 	int ret = -1;
177 	int new_state, state, skip = 0;
178 	int listen;
179 
180 	ERR_clear_error();
181 	errno = 0;
182 
183 	if (s->internal->info_callback != NULL)
184 		cb = s->internal->info_callback;
185 	else if (s->ctx->internal->info_callback != NULL)
186 		cb = s->ctx->internal->info_callback;
187 
188 	if (SSL_IS_DTLS(s))
189 		listen = D1I(s)->listen;
190 
191 	/* init things to blank */
192 	s->internal->in_handshake++;
193 	if (!SSL_in_init(s) || SSL_in_before(s))
194 		SSL_clear(s);
195 
196 	if (SSL_IS_DTLS(s))
197 		D1I(s)->listen = listen;
198 
199 	if (s->cert == NULL) {
200 		SSLerror(s, SSL_R_NO_CERTIFICATE_SET);
201 		ret = -1;
202 		goto end;
203 	}
204 
205 	for (;;) {
206 		state = S3I(s)->hs.state;
207 
208 		switch (S3I(s)->hs.state) {
209 		case SSL_ST_RENEGOTIATE:
210 			s->internal->renegotiate = 1;
211 			/* S3I(s)->hs.state=SSL_ST_ACCEPT; */
212 
213 		case SSL_ST_BEFORE:
214 		case SSL_ST_ACCEPT:
215 		case SSL_ST_BEFORE|SSL_ST_ACCEPT:
216 		case SSL_ST_OK|SSL_ST_ACCEPT:
217 			s->server = 1;
218 			if (cb != NULL)
219 				cb(s, SSL_CB_HANDSHAKE_START, 1);
220 
221 			if (SSL_IS_DTLS(s)) {
222 				if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
223 					SSLerror(s, ERR_R_INTERNAL_ERROR);
224 					ret = -1;
225 					goto end;
226 				}
227 			} else {
228 				if ((s->version >> 8) != 3) {
229 					SSLerror(s, ERR_R_INTERNAL_ERROR);
230 					ret = -1;
231 					goto end;
232 				}
233 			}
234 			s->internal->type = SSL_ST_ACCEPT;
235 
236 			if (!ssl3_setup_init_buffer(s)) {
237 				ret = -1;
238 				goto end;
239 			}
240 			if (!ssl3_setup_buffers(s)) {
241 				ret = -1;
242 				goto end;
243 			}
244 
245 			s->internal->init_num = 0;
246 
247 			if (S3I(s)->hs.state != SSL_ST_RENEGOTIATE) {
248 				/*
249 				 * Ok, we now need to push on a buffering BIO
250 				 * so that the output is sent in a way that
251 				 * TCP likes :-)
252 				 */
253 				if (!ssl_init_wbio_buffer(s, 1)) {
254 					ret = -1;
255 					goto end;
256 				}
257 				if (!tls1_init_finished_mac(s)) {
258 					ret = -1;
259 					goto end;
260 				}
261 
262 				S3I(s)->hs.state = SSL3_ST_SR_CLNT_HELLO_A;
263 				s->ctx->internal->stats.sess_accept++;
264 			} else if (!SSL_IS_DTLS(s) && !S3I(s)->send_connection_binding) {
265 				/*
266 				 * Server attempting to renegotiate with
267 				 * client that doesn't support secure
268 				 * renegotiation.
269 				 */
270 				SSLerror(s, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
271 				ssl3_send_alert(s, SSL3_AL_FATAL,
272 				    SSL_AD_HANDSHAKE_FAILURE);
273 				ret = -1;
274 				goto end;
275 			} else {
276 				/*
277 				 * S3I(s)->hs.state == SSL_ST_RENEGOTIATE,
278 				 * we will just send a HelloRequest.
279 				 */
280 				s->ctx->internal->stats.sess_accept_renegotiate++;
281 				S3I(s)->hs.state = SSL3_ST_SW_HELLO_REQ_A;
282 			}
283 			break;
284 
285 		case SSL3_ST_SW_HELLO_REQ_A:
286 		case SSL3_ST_SW_HELLO_REQ_B:
287 			s->internal->shutdown = 0;
288 			if (SSL_IS_DTLS(s)) {
289 				dtls1_clear_record_buffer(s);
290 				dtls1_start_timer(s);
291 			}
292 			ret = ssl3_send_hello_request(s);
293 			if (ret <= 0)
294 				goto end;
295 			if (SSL_IS_DTLS(s))
296 				S3I(s)->hs.next_state = SSL3_ST_SR_CLNT_HELLO_A;
297 			else
298 				S3I(s)->hs.next_state = SSL3_ST_SW_HELLO_REQ_C;
299 			S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
300 			s->internal->init_num = 0;
301 
302 			if (!tls1_init_finished_mac(s)) {
303 				ret = -1;
304 				goto end;
305 			}
306 			break;
307 
308 		case SSL3_ST_SW_HELLO_REQ_C:
309 			S3I(s)->hs.state = SSL_ST_OK;
310 			break;
311 
312 		case SSL3_ST_SR_CLNT_HELLO_A:
313 		case SSL3_ST_SR_CLNT_HELLO_B:
314 		case SSL3_ST_SR_CLNT_HELLO_C:
315 			s->internal->shutdown = 0;
316 			if (SSL_IS_DTLS(s)) {
317 				ret = ssl3_get_client_hello(s);
318 				if (ret <= 0)
319 					goto end;
320 				dtls1_stop_timer(s);
321 
322 				if (ret == 1 &&
323 				    (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
324 					S3I(s)->hs.state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
325 				else
326 					S3I(s)->hs.state = SSL3_ST_SW_SRVR_HELLO_A;
327 
328 				s->internal->init_num = 0;
329 
330 				/*
331 				 * Reflect ClientHello sequence to remain
332 				 * stateless while listening.
333 				 */
334 				if (listen) {
335 					memcpy(S3I(s)->write_sequence,
336 					    S3I(s)->read_sequence,
337 					    sizeof(S3I(s)->write_sequence));
338 				}
339 
340 				/* If we're just listening, stop here */
341 				if (listen && S3I(s)->hs.state == SSL3_ST_SW_SRVR_HELLO_A) {
342 					ret = 2;
343 					D1I(s)->listen = 0;
344 					/*
345 					 * Set expected sequence numbers to
346 					 * continue the handshake.
347 					 */
348 					D1I(s)->handshake_read_seq = 2;
349 					D1I(s)->handshake_write_seq = 1;
350 					D1I(s)->next_handshake_write_seq = 1;
351 					goto end;
352 				}
353 			} else {
354 				if (s->internal->rwstate != SSL_X509_LOOKUP) {
355 					ret = ssl3_get_client_hello(s);
356 					if (ret <= 0)
357 						goto end;
358 				}
359 
360 				s->internal->renegotiate = 2;
361 				S3I(s)->hs.state = SSL3_ST_SW_SRVR_HELLO_A;
362 				s->internal->init_num = 0;
363 			}
364 			break;
365 
366 		case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
367 		case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
368 			ret = dtls1_send_hello_verify_request(s);
369 			if (ret <= 0)
370 				goto end;
371 			S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
372 			S3I(s)->hs.next_state = SSL3_ST_SR_CLNT_HELLO_A;
373 
374 			/* HelloVerifyRequest resets Finished MAC. */
375 			if (!tls1_init_finished_mac(s)) {
376 				ret = -1;
377 				goto end;
378 			}
379 			break;
380 
381 		case SSL3_ST_SW_SRVR_HELLO_A:
382 		case SSL3_ST_SW_SRVR_HELLO_B:
383 			if (SSL_IS_DTLS(s)) {
384 				s->internal->renegotiate = 2;
385 				dtls1_start_timer(s);
386 			}
387 			ret = ssl3_send_server_hello(s);
388 			if (ret <= 0)
389 				goto end;
390 			if (s->internal->hit) {
391 				if (s->internal->tlsext_ticket_expected)
392 					S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_A;
393 				else
394 					S3I(s)->hs.state = SSL3_ST_SW_CHANGE_A;
395 			} else {
396 				S3I(s)->hs.state = SSL3_ST_SW_CERT_A;
397 			}
398 			s->internal->init_num = 0;
399 			break;
400 
401 		case SSL3_ST_SW_CERT_A:
402 		case SSL3_ST_SW_CERT_B:
403 			/* Check if it is anon DH or anon ECDH. */
404 			if (!(S3I(s)->hs.new_cipher->algorithm_auth &
405 			    SSL_aNULL)) {
406 				if (SSL_IS_DTLS(s))
407 					dtls1_start_timer(s);
408 				ret = ssl3_send_server_certificate(s);
409 				if (ret <= 0)
410 					goto end;
411 				if (s->internal->tlsext_status_expected)
412 					S3I(s)->hs.state = SSL3_ST_SW_CERT_STATUS_A;
413 				else
414 					S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_A;
415 			} else {
416 				skip = 1;
417 				S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_A;
418 			}
419 			s->internal->init_num = 0;
420 			break;
421 
422 		case SSL3_ST_SW_KEY_EXCH_A:
423 		case SSL3_ST_SW_KEY_EXCH_B:
424 			alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
425 
426 			/*
427 			 * Only send if using a DH key exchange.
428 			 *
429 			 * For ECC ciphersuites, we send a ServerKeyExchange
430 			 * message only if the cipher suite is ECDHE. In other
431 			 * cases, the server certificate contains the server's
432 			 * public key for key exchange.
433 			 */
434 			if (alg_k & (SSL_kDHE|SSL_kECDHE)) {
435 				if (SSL_IS_DTLS(s))
436 					dtls1_start_timer(s);
437 				ret = ssl3_send_server_key_exchange(s);
438 				if (ret <= 0)
439 					goto end;
440 			} else
441 				skip = 1;
442 
443 			S3I(s)->hs.state = SSL3_ST_SW_CERT_REQ_A;
444 			s->internal->init_num = 0;
445 			break;
446 
447 		case SSL3_ST_SW_CERT_REQ_A:
448 		case SSL3_ST_SW_CERT_REQ_B:
449 			/*
450 			 * Determine whether or not we need to request a
451 			 * certificate.
452 			 *
453 			 * Do not request a certificate if:
454 			 *
455 			 * - We did not ask for it (SSL_VERIFY_PEER is unset).
456 			 *
457 			 * - SSL_VERIFY_CLIENT_ONCE is set and we are
458 			 *   renegotiating.
459 			 *
460 			 * - We are using an anonymous ciphersuites
461 			 *   (see section "Certificate request" in SSL 3 drafts
462 			 *   and in RFC 2246) ... except when the application
463 			 *   insists on verification (against the specs, but
464 			 *   s3_clnt.c accepts this for SSL 3).
465 			 */
466 			if (!(s->verify_mode & SSL_VERIFY_PEER) ||
467 			    ((s->session->peer != NULL) &&
468 			     (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
469 			    ((S3I(s)->hs.new_cipher->algorithm_auth &
470 			     SSL_aNULL) && !(s->verify_mode &
471 			     SSL_VERIFY_FAIL_IF_NO_PEER_CERT))) {
472 				/* No cert request. */
473 				skip = 1;
474 				S3I(s)->tmp.cert_request = 0;
475 				S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_A;
476 				if (!SSL_IS_DTLS(s) && S3I(s)->handshake_buffer) {
477 					if (!tls1_digest_cached_records(s)) {
478 						ret = -1;
479 						goto end;
480 					}
481 				}
482 			} else {
483 				S3I(s)->tmp.cert_request = 1;
484 				if (SSL_IS_DTLS(s))
485 					dtls1_start_timer(s);
486 				ret = ssl3_send_certificate_request(s);
487 				if (ret <= 0)
488 					goto end;
489 				S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_A;
490 				s->internal->init_num = 0;
491 			}
492 			break;
493 
494 		case SSL3_ST_SW_SRVR_DONE_A:
495 		case SSL3_ST_SW_SRVR_DONE_B:
496 			if (SSL_IS_DTLS(s))
497 				dtls1_start_timer(s);
498 			ret = ssl3_send_server_done(s);
499 			if (ret <= 0)
500 				goto end;
501 			S3I(s)->hs.next_state = SSL3_ST_SR_CERT_A;
502 			S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
503 			s->internal->init_num = 0;
504 			break;
505 
506 		case SSL3_ST_SW_FLUSH:
507 			/*
508 			 * This code originally checked to see if
509 			 * any data was pending using BIO_CTRL_INFO
510 			 * and then flushed. This caused problems
511 			 * as documented in PR#1939. The proposed
512 			 * fix doesn't completely resolve this issue
513 			 * as buggy implementations of BIO_CTRL_PENDING
514 			 * still exist. So instead we just flush
515 			 * unconditionally.
516 			 */
517 			s->internal->rwstate = SSL_WRITING;
518 			if (BIO_flush(s->wbio) <= 0) {
519 				if (SSL_IS_DTLS(s)) {
520 					/* If the write error was fatal, stop trying. */
521 					if (!BIO_should_retry(s->wbio)) {
522 						s->internal->rwstate = SSL_NOTHING;
523 						S3I(s)->hs.state = S3I(s)->hs.next_state;
524 					}
525 				}
526 				ret = -1;
527 				goto end;
528 			}
529 			s->internal->rwstate = SSL_NOTHING;
530 			S3I(s)->hs.state = S3I(s)->hs.next_state;
531 			break;
532 
533 		case SSL3_ST_SR_CERT_A:
534 		case SSL3_ST_SR_CERT_B:
535 			if (S3I(s)->tmp.cert_request) {
536 				ret = ssl3_get_client_certificate(s);
537 				if (ret <= 0)
538 					goto end;
539 			}
540 			s->internal->init_num = 0;
541 			S3I(s)->hs.state = SSL3_ST_SR_KEY_EXCH_A;
542 			break;
543 
544 		case SSL3_ST_SR_KEY_EXCH_A:
545 		case SSL3_ST_SR_KEY_EXCH_B:
546 			ret = ssl3_get_client_key_exchange(s);
547 			if (ret <= 0)
548 				goto end;
549 
550 			if (SSL_IS_DTLS(s)) {
551 				S3I(s)->hs.state = SSL3_ST_SR_CERT_VRFY_A;
552 				s->internal->init_num = 0;
553 			}
554 
555 			alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
556 			if (ret == 2) {
557 				/*
558 				 * For the ECDH ciphersuites when
559 				 * the client sends its ECDH pub key in
560 				 * a certificate, the CertificateVerify
561 				 * message is not sent.
562 				 * Also for GOST ciphersuites when
563 				 * the client uses its key from the certificate
564 				 * for key exchange.
565 				 */
566 				S3I(s)->hs.state = SSL3_ST_SR_FINISHED_A;
567 				s->internal->init_num = 0;
568 			} else if (SSL_USE_SIGALGS(s) || (alg_k & SSL_kGOST)) {
569 				S3I(s)->hs.state = SSL3_ST_SR_CERT_VRFY_A;
570 				s->internal->init_num = 0;
571 				if (!s->session->peer)
572 					break;
573 				/*
574 				 * For sigalgs freeze the handshake buffer
575 				 * at this point and digest cached records.
576 				 */
577 				if (!S3I(s)->handshake_buffer) {
578 					SSLerror(s, ERR_R_INTERNAL_ERROR);
579 					ret = -1;
580 					goto end;
581 				}
582 				s->s3->flags |= TLS1_FLAGS_KEEP_HANDSHAKE;
583 				if (!tls1_digest_cached_records(s)) {
584 					ret = -1;
585 					goto end;
586 				}
587 			} else {
588 				S3I(s)->hs.state = SSL3_ST_SR_CERT_VRFY_A;
589 				s->internal->init_num = 0;
590 
591 				/*
592 				 * We need to get hashes here so if there is
593 				 * a client cert, it can be verified.
594 				 */
595 				if (S3I(s)->handshake_buffer) {
596 					if (!tls1_digest_cached_records(s)) {
597 						ret = -1;
598 						goto end;
599 					}
600 				}
601 				if (!tls1_handshake_hash_value(s,
602 				    S3I(s)->tmp.cert_verify_md,
603 				    sizeof(S3I(s)->tmp.cert_verify_md),
604 				    NULL)) {
605 					ret = -1;
606 					goto end;
607 				}
608 			}
609 			break;
610 
611 		case SSL3_ST_SR_CERT_VRFY_A:
612 		case SSL3_ST_SR_CERT_VRFY_B:
613 			if (SSL_IS_DTLS(s))
614 				D1I(s)->change_cipher_spec_ok = 1;
615 			else
616 				s->s3->flags |= SSL3_FLAGS_CCS_OK;
617 
618 			/* we should decide if we expected this one */
619 			ret = ssl3_get_cert_verify(s);
620 			if (ret <= 0)
621 				goto end;
622 			S3I(s)->hs.state = SSL3_ST_SR_FINISHED_A;
623 			s->internal->init_num = 0;
624 			break;
625 
626 		case SSL3_ST_SR_FINISHED_A:
627 		case SSL3_ST_SR_FINISHED_B:
628 			if (SSL_IS_DTLS(s))
629 				D1I(s)->change_cipher_spec_ok = 1;
630 			else
631 				s->s3->flags |= SSL3_FLAGS_CCS_OK;
632 			ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
633 			    SSL3_ST_SR_FINISHED_B);
634 			if (ret <= 0)
635 				goto end;
636 			if (SSL_IS_DTLS(s))
637 				dtls1_stop_timer(s);
638 			if (s->internal->hit)
639 				S3I(s)->hs.state = SSL_ST_OK;
640 			else if (s->internal->tlsext_ticket_expected)
641 				S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_A;
642 			else
643 				S3I(s)->hs.state = SSL3_ST_SW_CHANGE_A;
644 			s->internal->init_num = 0;
645 			break;
646 
647 		case SSL3_ST_SW_SESSION_TICKET_A:
648 		case SSL3_ST_SW_SESSION_TICKET_B:
649 			ret = ssl3_send_newsession_ticket(s);
650 			if (ret <= 0)
651 				goto end;
652 			S3I(s)->hs.state = SSL3_ST_SW_CHANGE_A;
653 			s->internal->init_num = 0;
654 			break;
655 
656 		case SSL3_ST_SW_CERT_STATUS_A:
657 		case SSL3_ST_SW_CERT_STATUS_B:
658 			ret = ssl3_send_cert_status(s);
659 			if (ret <= 0)
660 				goto end;
661 			S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_A;
662 			s->internal->init_num = 0;
663 			break;
664 
665 		case SSL3_ST_SW_CHANGE_A:
666 		case SSL3_ST_SW_CHANGE_B:
667 			s->session->cipher = S3I(s)->hs.new_cipher;
668 			if (!tls1_setup_key_block(s)) {
669 				ret = -1;
670 				goto end;
671 			}
672 
673 			ret = ssl3_send_change_cipher_spec(s,
674 			    SSL3_ST_SW_CHANGE_A, SSL3_ST_SW_CHANGE_B);
675 			if (ret <= 0)
676 				goto end;
677 			S3I(s)->hs.state = SSL3_ST_SW_FINISHED_A;
678 			s->internal->init_num = 0;
679 
680 			if (!tls1_change_cipher_state(s,
681 			    SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
682 				ret = -1;
683 				goto end;
684 			}
685 
686 			if (SSL_IS_DTLS(s))
687 				dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
688 			break;
689 
690 		case SSL3_ST_SW_FINISHED_A:
691 		case SSL3_ST_SW_FINISHED_B:
692 			ret = ssl3_send_finished(s,
693 			    SSL3_ST_SW_FINISHED_A, SSL3_ST_SW_FINISHED_B,
694 			    TLS_MD_SERVER_FINISH_CONST,
695 			    TLS_MD_SERVER_FINISH_CONST_SIZE);
696 			if (ret <= 0)
697 				goto end;
698 			S3I(s)->hs.state = SSL3_ST_SW_FLUSH;
699 			if (s->internal->hit)
700 				S3I(s)->hs.next_state = SSL3_ST_SR_FINISHED_A;
701 			else
702 				S3I(s)->hs.next_state = SSL_ST_OK;
703 			s->internal->init_num = 0;
704 			break;
705 
706 		case SSL_ST_OK:
707 			/* clean a few things up */
708 			tls1_cleanup_key_block(s);
709 
710 			if (!SSL_IS_DTLS(s)) {
711 				BUF_MEM_free(s->internal->init_buf);
712 				s->internal->init_buf = NULL;
713 			}
714 
715 			/* remove buffering on output */
716 			ssl_free_wbio_buffer(s);
717 
718 			s->internal->init_num = 0;
719 
720 			/* Skipped if we just sent a HelloRequest. */
721 			if (s->internal->renegotiate == 2) {
722 				s->internal->renegotiate = 0;
723 				s->internal->new_session = 0;
724 
725 				ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
726 
727 				s->ctx->internal->stats.sess_accept_good++;
728 				/* s->server=1; */
729 				s->internal->handshake_func = ssl3_accept;
730 
731 				if (cb != NULL)
732 					cb(s, SSL_CB_HANDSHAKE_DONE, 1);
733 			}
734 
735 			ret = 1;
736 
737 			if (SSL_IS_DTLS(s)) {
738 				/* Done handshaking, next message is client hello. */
739 				D1I(s)->handshake_read_seq = 0;
740 				/* Next message is server hello. */
741 				D1I(s)->handshake_write_seq = 0;
742 				D1I(s)->next_handshake_write_seq = 0;
743 			}
744 			goto end;
745 			/* break; */
746 
747 		default:
748 			SSLerror(s, SSL_R_UNKNOWN_STATE);
749 			ret = -1;
750 			goto end;
751 			/* break; */
752 		}
753 
754 		if (!S3I(s)->tmp.reuse_message && !skip) {
755 			if (s->internal->debug) {
756 				if ((ret = BIO_flush(s->wbio)) <= 0)
757 					goto end;
758 			}
759 
760 
761 			if ((cb != NULL) && (S3I(s)->hs.state != state)) {
762 				new_state = S3I(s)->hs.state;
763 				S3I(s)->hs.state = state;
764 				cb(s, SSL_CB_ACCEPT_LOOP, 1);
765 				S3I(s)->hs.state = new_state;
766 			}
767 		}
768 		skip = 0;
769 	}
770 end:
771 	/* BIO_flush(s->wbio); */
772 	s->internal->in_handshake--;
773 	if (cb != NULL)
774 		cb(s, SSL_CB_ACCEPT_EXIT, ret);
775 
776 	return (ret);
777 }
778 
779 int
780 ssl3_send_hello_request(SSL *s)
781 {
782 	CBB cbb, hello;
783 
784 	memset(&cbb, 0, sizeof(cbb));
785 
786 	if (S3I(s)->hs.state == SSL3_ST_SW_HELLO_REQ_A) {
787 		if (!ssl3_handshake_msg_start_cbb(s, &cbb, &hello,
788 		    SSL3_MT_HELLO_REQUEST))
789 			goto err;
790 		if (!ssl3_handshake_msg_finish_cbb(s, &cbb))
791 			goto err;
792 
793 		S3I(s)->hs.state = SSL3_ST_SW_HELLO_REQ_B;
794 	}
795 
796 	/* SSL3_ST_SW_HELLO_REQ_B */
797 	return (ssl3_handshake_write(s));
798 
799  err:
800 	CBB_cleanup(&cbb);
801 
802 	return (-1);
803 }
804 
805 int
806 ssl3_get_client_hello(SSL *s)
807 {
808 	CBS cbs, client_random, session_id, cookie, cipher_suites;
809 	CBS compression_methods;
810 	uint16_t client_version;
811 	uint8_t comp_method;
812 	int comp_null;
813 	int i, j, ok, al, ret = -1, cookie_valid = 0;
814 	long n;
815 	unsigned long id;
816 	unsigned char *p, *d;
817 	SSL_CIPHER *c;
818 	STACK_OF(SSL_CIPHER) *ciphers = NULL;
819 	unsigned long alg_k;
820 	const SSL_METHOD *method;
821 	uint16_t shared_version;
822 	unsigned char *end;
823 
824 	/*
825 	 * We do this so that we will respond with our native type.
826 	 * If we are TLSv1 and we get SSLv3, we will respond with TLSv1,
827 	 * This down switching should be handled by a different method.
828 	 * If we are SSLv3, we will respond with SSLv3, even if prompted with
829 	 * TLSv1.
830 	 */
831 	if (S3I(s)->hs.state == SSL3_ST_SR_CLNT_HELLO_A) {
832 		S3I(s)->hs.state = SSL3_ST_SR_CLNT_HELLO_B;
833 	}
834 
835 	s->internal->first_packet = 1;
836 	n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_CLNT_HELLO_B,
837 	    SSL3_ST_SR_CLNT_HELLO_C, SSL3_MT_CLIENT_HELLO,
838 	    SSL3_RT_MAX_PLAIN_LENGTH, &ok);
839 	if (!ok)
840 		return ((int)n);
841 	s->internal->first_packet = 0;
842 
843 	if (n < 0)
844 		goto err;
845 
846 	d = p = (unsigned char *)s->internal->init_msg;
847 	end = d + n;
848 
849 	CBS_init(&cbs, s->internal->init_msg, n);
850 
851 	/*
852 	 * Use version from inside client hello, not from record header.
853 	 * (may differ: see RFC 2246, Appendix E, second paragraph)
854 	 */
855 	if (!CBS_get_u16(&cbs, &client_version))
856 		goto truncated;
857 
858 	if (ssl_max_shared_version(s, client_version, &shared_version) != 1) {
859 		SSLerror(s, SSL_R_WRONG_VERSION_NUMBER);
860 		if ((s->client_version >> 8) == SSL3_VERSION_MAJOR &&
861 		    !s->internal->enc_write_ctx && !s->internal->write_hash) {
862 			/*
863 			 * Similar to ssl3_get_record, send alert using remote
864 			 * version number.
865 			 */
866 			s->version = s->client_version;
867 		}
868 		al = SSL_AD_PROTOCOL_VERSION;
869 		goto f_err;
870 	}
871 	s->client_version = client_version;
872 	s->version = shared_version;
873 
874 	if ((method = tls1_get_server_method(shared_version)) == NULL)
875 		method = dtls1_get_server_method(shared_version);
876 	if (method == NULL) {
877 		SSLerror(s, ERR_R_INTERNAL_ERROR);
878 		goto err;
879 	}
880 	s->method = method;
881 
882 	if (!CBS_get_bytes(&cbs, &client_random, SSL3_RANDOM_SIZE))
883 		goto truncated;
884 	if (!CBS_get_u8_length_prefixed(&cbs, &session_id))
885 		goto truncated;
886 
887 	/*
888 	 * If we require cookies (DTLS) and this ClientHello doesn't
889 	 * contain one, just return since we do not want to
890 	 * allocate any memory yet. So check cookie length...
891 	 */
892 	if (SSL_IS_DTLS(s)) {
893 		if (!CBS_get_u8_length_prefixed(&cbs, &cookie))
894 			goto truncated;
895 		if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
896 			if (CBS_len(&cookie) == 0)
897 				return (1);
898 		}
899 	}
900 
901 	if (!CBS_write_bytes(&client_random, s->s3->client_random,
902 	    sizeof(s->s3->client_random), NULL))
903 		goto err;
904 
905 	s->internal->hit = 0;
906 
907 	/*
908 	 * Versions before 0.9.7 always allow clients to resume sessions in
909 	 * renegotiation. 0.9.7 and later allow this by default, but optionally
910 	 * ignore resumption requests with flag
911 	 * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag
912 	 * rather than a change to default behavior so that applications
913 	 * relying on this for security won't even compile against older
914 	 * library versions).
915 	 *
916 	 * 1.0.1 and later also have a function SSL_renegotiate_abbreviated()
917 	 * to request renegotiation but not a new session (s->internal->new_session
918 	 * remains unset): for servers, this essentially just means that the
919 	 * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
920 	 * ignored.
921 	 */
922 	if ((s->internal->new_session && (s->internal->options &
923 	    SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
924 		if (!ssl_get_new_session(s, 1))
925 			goto err;
926 	} else {
927 		/* XXX - pass CBS through instead... */
928 		i = ssl_get_prev_session(s,
929 		    (unsigned char *)CBS_data(&session_id),
930 		    CBS_len(&session_id), end);
931 		if (i == 1) { /* previous session */
932 			s->internal->hit = 1;
933 		} else if (i == -1)
934 			goto err;
935 		else {
936 			/* i == 0 */
937 			if (!ssl_get_new_session(s, 1))
938 				goto err;
939 		}
940 	}
941 
942 	if (SSL_IS_DTLS(s)) {
943 		/*
944 		 * The ClientHello may contain a cookie even if the HelloVerify
945 		 * message has not been sent - make sure that it does not cause
946 		 * an overflow.
947 		 */
948 		if (CBS_len(&cookie) > sizeof(D1I(s)->rcvd_cookie)) {
949 			al = SSL_AD_DECODE_ERROR;
950 			SSLerror(s, SSL_R_COOKIE_MISMATCH);
951 			goto f_err;
952 		}
953 
954 		/* Verify the cookie if appropriate option is set. */
955 		if ((SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) &&
956 		    CBS_len(&cookie) > 0) {
957 			size_t cookie_len;
958 
959 			/* XXX - rcvd_cookie seems to only be used here... */
960 			if (!CBS_write_bytes(&cookie, D1I(s)->rcvd_cookie,
961 			    sizeof(D1I(s)->rcvd_cookie), &cookie_len))
962 				goto err;
963 
964 			if (s->ctx->internal->app_verify_cookie_cb != NULL) {
965 				if (s->ctx->internal->app_verify_cookie_cb(s,
966 				    D1I(s)->rcvd_cookie, cookie_len) == 0) {
967 					al = SSL_AD_HANDSHAKE_FAILURE;
968 					SSLerror(s, SSL_R_COOKIE_MISMATCH);
969 					goto f_err;
970 				}
971 				/* else cookie verification succeeded */
972 			/* XXX - can d1->cookie_len > sizeof(rcvd_cookie) ? */
973 			} else if (timingsafe_memcmp(D1I(s)->rcvd_cookie,
974 			    D1I(s)->cookie, D1I(s)->cookie_len) != 0) {
975 				/* default verification */
976 				al = SSL_AD_HANDSHAKE_FAILURE;
977 				SSLerror(s, SSL_R_COOKIE_MISMATCH);
978 				goto f_err;
979 			}
980 			cookie_valid = 1;
981 		}
982 	}
983 
984 	if (!CBS_get_u16_length_prefixed(&cbs, &cipher_suites))
985 		goto truncated;
986 
987 	/* XXX - This logic seems wrong... */
988 	if (CBS_len(&cipher_suites) == 0 && CBS_len(&session_id) != 0) {
989 		/* we need a cipher if we are not resuming a session */
990 		al = SSL_AD_ILLEGAL_PARAMETER;
991 		SSLerror(s, SSL_R_NO_CIPHERS_SPECIFIED);
992 		goto f_err;
993 	}
994 
995 	if (CBS_len(&cipher_suites) > 0) {
996 		if ((ciphers = ssl_bytes_to_cipher_list(s,
997 		    &cipher_suites)) == NULL)
998 			goto err;
999 	}
1000 
1001 	/* If it is a hit, check that the cipher is in the list */
1002 	/* XXX - CBS_len(&cipher_suites) will always be zero here... */
1003 	if (s->internal->hit && CBS_len(&cipher_suites) > 0) {
1004 		j = 0;
1005 		id = s->session->cipher->id;
1006 
1007 		for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
1008 			c = sk_SSL_CIPHER_value(ciphers, i);
1009 			if (c->id == id) {
1010 				j = 1;
1011 				break;
1012 			}
1013 		}
1014 		if (j == 0) {
1015 			/*
1016 			 * We need to have the cipher in the cipher
1017 			 * list if we are asked to reuse it
1018 			 */
1019 			al = SSL_AD_ILLEGAL_PARAMETER;
1020 			SSLerror(s, SSL_R_REQUIRED_CIPHER_MISSING);
1021 			goto f_err;
1022 		}
1023 	}
1024 
1025 	if (!CBS_get_u8_length_prefixed(&cbs, &compression_methods))
1026 		goto truncated;
1027 
1028 	comp_null = 0;
1029 	while (CBS_len(&compression_methods) > 0) {
1030 		if (!CBS_get_u8(&compression_methods, &comp_method))
1031 			goto truncated;
1032 		if (comp_method == 0)
1033 			comp_null = 1;
1034 	}
1035 	if (comp_null == 0) {
1036 		al = SSL_AD_DECODE_ERROR;
1037 		SSLerror(s, SSL_R_NO_COMPRESSION_SPECIFIED);
1038 		goto f_err;
1039 	}
1040 
1041 	p = (unsigned char *)CBS_data(&cbs);
1042 
1043 	/* TLS extensions*/
1044 	if (!ssl_parse_clienthello_tlsext(s, &p, d, n, &al)) {
1045 		/* 'al' set by ssl_parse_clienthello_tlsext */
1046 		SSLerror(s, SSL_R_PARSE_TLSEXT);
1047 		goto f_err;
1048 	}
1049 	if (ssl_check_clienthello_tlsext_early(s) <= 0) {
1050 		SSLerror(s, SSL_R_CLIENTHELLO_TLSEXT);
1051 		goto err;
1052 	}
1053 
1054 	/*
1055 	 * Check if we want to use external pre-shared secret for this
1056 	 * handshake for not reused session only. We need to generate
1057 	 * server_random before calling tls_session_secret_cb in order to allow
1058 	 * SessionTicket processing to use it in key derivation.
1059 	 */
1060 	arc4random_buf(s->s3->server_random, SSL3_RANDOM_SIZE);
1061 
1062 	if (!s->internal->hit && s->internal->tls_session_secret_cb) {
1063 		SSL_CIPHER *pref_cipher = NULL;
1064 
1065 		s->session->master_key_length = sizeof(s->session->master_key);
1066 		if (s->internal->tls_session_secret_cb(s, s->session->master_key,
1067 		    &s->session->master_key_length, ciphers, &pref_cipher,
1068 		    s->internal->tls_session_secret_cb_arg)) {
1069 			s->internal->hit = 1;
1070 			s->session->ciphers = ciphers;
1071 			s->session->verify_result = X509_V_OK;
1072 
1073 			ciphers = NULL;
1074 
1075 			/* check if some cipher was preferred by call back */
1076 			pref_cipher = pref_cipher ? pref_cipher :
1077 			    ssl3_choose_cipher(s, s->session->ciphers,
1078 			    SSL_get_ciphers(s));
1079 			if (pref_cipher == NULL) {
1080 				al = SSL_AD_HANDSHAKE_FAILURE;
1081 				SSLerror(s, SSL_R_NO_SHARED_CIPHER);
1082 				goto f_err;
1083 			}
1084 
1085 			s->session->cipher = pref_cipher;
1086 
1087 			sk_SSL_CIPHER_free(s->cipher_list);
1088 			sk_SSL_CIPHER_free(s->internal->cipher_list_by_id);
1089 
1090 			s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
1091 			s->internal->cipher_list_by_id =
1092 			    sk_SSL_CIPHER_dup(s->session->ciphers);
1093 		}
1094 	}
1095 
1096 	/*
1097 	 * Given s->session->ciphers and SSL_get_ciphers, we must
1098 	 * pick a cipher
1099 	 */
1100 
1101 	if (!s->internal->hit) {
1102 		sk_SSL_CIPHER_free(s->session->ciphers);
1103 		s->session->ciphers = ciphers;
1104 		if (ciphers == NULL) {
1105 			al = SSL_AD_ILLEGAL_PARAMETER;
1106 			SSLerror(s, SSL_R_NO_CIPHERS_PASSED);
1107 			goto f_err;
1108 		}
1109 		ciphers = NULL;
1110 		c = ssl3_choose_cipher(s, s->session->ciphers,
1111 		SSL_get_ciphers(s));
1112 
1113 		if (c == NULL) {
1114 			al = SSL_AD_HANDSHAKE_FAILURE;
1115 			SSLerror(s, SSL_R_NO_SHARED_CIPHER);
1116 			goto f_err;
1117 		}
1118 		S3I(s)->hs.new_cipher = c;
1119 	} else {
1120 		S3I(s)->hs.new_cipher = s->session->cipher;
1121 	}
1122 
1123 	if (!tls1_handshake_hash_init(s))
1124 		goto err;
1125 
1126 	alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
1127 	if (!(SSL_USE_SIGALGS(s) || (alg_k & SSL_kGOST)) ||
1128 	    !(s->verify_mode & SSL_VERIFY_PEER)) {
1129 		if (!tls1_digest_cached_records(s)) {
1130 			al = SSL_AD_INTERNAL_ERROR;
1131 			goto f_err;
1132 		}
1133 	}
1134 
1135 	/*
1136 	 * We now have the following setup.
1137 	 * client_random
1138 	 * cipher_list 		- our prefered list of ciphers
1139 	 * ciphers 		- the clients prefered list of ciphers
1140 	 * compression		- basically ignored right now
1141 	 * ssl version is set	- sslv3
1142 	 * s->session		- The ssl session has been setup.
1143 	 * s->internal->hit		- session reuse flag
1144 	 * s->hs.new_cipher	- the new cipher to use.
1145 	 */
1146 
1147 	/* Handles TLS extensions that we couldn't check earlier */
1148 	if (ssl_check_clienthello_tlsext_late(s) <= 0) {
1149 		SSLerror(s, SSL_R_CLIENTHELLO_TLSEXT);
1150 		goto err;
1151 	}
1152 
1153 	ret = cookie_valid ? 2 : 1;
1154 
1155 	if (0) {
1156 truncated:
1157 		al = SSL_AD_DECODE_ERROR;
1158 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1159 f_err:
1160 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
1161 	}
1162 err:
1163 	sk_SSL_CIPHER_free(ciphers);
1164 
1165 	return (ret);
1166 }
1167 
1168 int
1169 ssl3_send_server_hello(SSL *s)
1170 {
1171 	CBB cbb, server_hello, session_id;
1172 	size_t sl;
1173 
1174 	memset(&cbb, 0, sizeof(cbb));
1175 
1176 	if (S3I(s)->hs.state == SSL3_ST_SW_SRVR_HELLO_A) {
1177 		if (!ssl3_handshake_msg_start_cbb(s, &cbb, &server_hello,
1178 		    SSL3_MT_SERVER_HELLO))
1179 			goto err;
1180 
1181 		if (!CBB_add_u16(&server_hello, s->version))
1182 			goto err;
1183 		if (!CBB_add_bytes(&server_hello, s->s3->server_random,
1184 		    sizeof(s->s3->server_random)))
1185 			goto err;
1186 
1187 		/*
1188 		 * There are several cases for the session ID to send
1189 		 * back in the server hello:
1190 		 *
1191 		 * - For session reuse from the session cache,
1192 		 *   we send back the old session ID.
1193 		 * - If stateless session reuse (using a session ticket)
1194 		 *   is successful, we send back the client's "session ID"
1195 		 *   (which doesn't actually identify the session).
1196 		 * - If it is a new session, we send back the new
1197 		 *   session ID.
1198 		 * - However, if we want the new session to be single-use,
1199 		 *   we send back a 0-length session ID.
1200 		 *
1201 		 * s->internal->hit is non-zero in either case of session reuse,
1202 		 * so the following won't overwrite an ID that we're supposed
1203 		 * to send back.
1204 		 */
1205 		if (!(s->ctx->internal->session_cache_mode & SSL_SESS_CACHE_SERVER)
1206 		    && !s->internal->hit)
1207 			s->session->session_id_length = 0;
1208 
1209 		sl = s->session->session_id_length;
1210 		if (sl > sizeof(s->session->session_id)) {
1211 			SSLerror(s, ERR_R_INTERNAL_ERROR);
1212 			goto err;
1213 		}
1214 		if (!CBB_add_u8_length_prefixed(&server_hello, &session_id))
1215 			goto err;
1216 		if (!CBB_add_bytes(&session_id, s->session->session_id, sl))
1217 			goto err;
1218 
1219 		/* Cipher suite. */
1220 		if (!CBB_add_u16(&server_hello,
1221 		    ssl3_cipher_get_value(S3I(s)->hs.new_cipher)))
1222 			goto err;
1223 
1224 		/* Compression method (null). */
1225 		if (!CBB_add_u8(&server_hello, 0))
1226 			goto err;
1227 
1228 		/* TLS extensions */
1229 		if (!tlsext_serverhello_build(s, &server_hello)) {
1230 			SSLerror(s, ERR_R_INTERNAL_ERROR);
1231 			goto err;
1232 		}
1233 
1234 		if (!ssl3_handshake_msg_finish_cbb(s, &cbb))
1235 			goto err;
1236 	}
1237 
1238 	/* SSL3_ST_SW_SRVR_HELLO_B */
1239 	return (ssl3_handshake_write(s));
1240 
1241  err:
1242 	CBB_cleanup(&cbb);
1243 
1244 	return (-1);
1245 }
1246 
1247 int
1248 ssl3_send_server_done(SSL *s)
1249 {
1250 	CBB cbb, done;
1251 
1252 	memset(&cbb, 0, sizeof(cbb));
1253 
1254 	if (S3I(s)->hs.state == SSL3_ST_SW_SRVR_DONE_A) {
1255 		if (!ssl3_handshake_msg_start_cbb(s, &cbb, &done,
1256 		    SSL3_MT_SERVER_DONE))
1257 			goto err;
1258 		if (!ssl3_handshake_msg_finish_cbb(s, &cbb))
1259 			goto err;
1260 
1261 		S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_B;
1262 	}
1263 
1264 	/* SSL3_ST_SW_SRVR_DONE_B */
1265 	return (ssl3_handshake_write(s));
1266 
1267  err:
1268 	CBB_cleanup(&cbb);
1269 
1270 	return (-1);
1271 }
1272 
1273 int
1274 ssl3_send_server_kex_dhe(SSL *s, CBB *cbb)
1275 {
1276 	CBB dh_p, dh_g, dh_Ys;
1277 	DH *dh = NULL, *dhp;
1278 	unsigned char *data;
1279 	int al;
1280 
1281 	if (s->cert->dh_tmp_auto != 0) {
1282 		if ((dhp = ssl_get_auto_dh(s)) == NULL) {
1283 			al = SSL_AD_INTERNAL_ERROR;
1284 			SSLerror(s, ERR_R_INTERNAL_ERROR);
1285 			goto f_err;
1286 		}
1287 	} else
1288 		dhp = s->cert->dh_tmp;
1289 
1290 	if (dhp == NULL && s->cert->dh_tmp_cb != NULL)
1291 		dhp = s->cert->dh_tmp_cb(s, 0,
1292 		    SSL_C_PKEYLENGTH(S3I(s)->hs.new_cipher));
1293 
1294 	if (dhp == NULL) {
1295 		al = SSL_AD_HANDSHAKE_FAILURE;
1296 		SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
1297 		goto f_err;
1298 	}
1299 
1300 	if (S3I(s)->tmp.dh != NULL) {
1301 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1302 		goto err;
1303 	}
1304 
1305 	if (s->cert->dh_tmp_auto != 0) {
1306 		dh = dhp;
1307 	} else if ((dh = DHparams_dup(dhp)) == NULL) {
1308 		SSLerror(s, ERR_R_DH_LIB);
1309 		goto err;
1310 	}
1311 	S3I(s)->tmp.dh = dh;
1312 	if (!DH_generate_key(dh)) {
1313 		SSLerror(s, ERR_R_DH_LIB);
1314 		goto err;
1315 	}
1316 
1317 	/*
1318 	 * Serialize the DH parameters and public key.
1319 	 */
1320 	if (!CBB_add_u16_length_prefixed(cbb, &dh_p))
1321 		goto err;
1322 	if (!CBB_add_space(&dh_p, &data, BN_num_bytes(dh->p)))
1323 		goto err;
1324 	BN_bn2bin(dh->p, data);
1325 
1326 	if (!CBB_add_u16_length_prefixed(cbb, &dh_g))
1327 		goto err;
1328 	if (!CBB_add_space(&dh_g, &data, BN_num_bytes(dh->g)))
1329 		goto err;
1330 	BN_bn2bin(dh->g, data);
1331 
1332 	if (!CBB_add_u16_length_prefixed(cbb, &dh_Ys))
1333 		goto err;
1334 	if (!CBB_add_space(&dh_Ys, &data, BN_num_bytes(dh->pub_key)))
1335 		goto err;
1336 	BN_bn2bin(dh->pub_key, data);
1337 
1338 	if (!CBB_flush(cbb))
1339 		goto err;
1340 
1341 	return (1);
1342 
1343  f_err:
1344 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1345  err:
1346 	return (-1);
1347 }
1348 
1349 static int
1350 ssl3_send_server_kex_ecdhe_ecp(SSL *s, int nid, CBB *cbb)
1351 {
1352 	const EC_GROUP *group;
1353 	const EC_POINT *pubkey;
1354 	unsigned char *data;
1355 	int encoded_len = 0;
1356 	int curve_id = 0;
1357 	BN_CTX *bn_ctx = NULL;
1358 	EC_KEY *ecdh;
1359 	CBB ecpoint;
1360 	int al;
1361 
1362 	/*
1363 	 * Only named curves are supported in ECDH ephemeral key exchanges.
1364 	 * For supported named curves, curve_id is non-zero.
1365 	 */
1366 	if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
1367 		SSLerror(s, SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
1368 		goto err;
1369 	}
1370 
1371 	if (S3I(s)->tmp.ecdh != NULL) {
1372 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1373 		goto err;
1374 	}
1375 
1376 	if ((S3I(s)->tmp.ecdh = EC_KEY_new_by_curve_name(nid)) == NULL) {
1377 		al = SSL_AD_HANDSHAKE_FAILURE;
1378 		SSLerror(s, SSL_R_MISSING_TMP_ECDH_KEY);
1379 		goto f_err;
1380 	}
1381 	ecdh = S3I(s)->tmp.ecdh;
1382 
1383 	if (!EC_KEY_generate_key(ecdh)) {
1384 		SSLerror(s, ERR_R_ECDH_LIB);
1385 		goto err;
1386 	}
1387 	if ((group = EC_KEY_get0_group(ecdh)) == NULL ||
1388 	    (pubkey = EC_KEY_get0_public_key(ecdh)) == NULL ||
1389 	    EC_KEY_get0_private_key(ecdh) == NULL) {
1390 		SSLerror(s, ERR_R_ECDH_LIB);
1391 		goto err;
1392 	}
1393 
1394 	/*
1395 	 * Encode the public key.
1396 	 */
1397 	encoded_len = EC_POINT_point2oct(group, pubkey,
1398 	    POINT_CONVERSION_UNCOMPRESSED, NULL, 0, NULL);
1399 	if (encoded_len == 0) {
1400 		SSLerror(s, ERR_R_ECDH_LIB);
1401 		goto err;
1402 	}
1403 	if ((bn_ctx = BN_CTX_new()) == NULL) {
1404 		SSLerror(s, ERR_R_MALLOC_FAILURE);
1405 		goto err;
1406 	}
1407 
1408 	/*
1409 	 * Only named curves are supported in ECDH ephemeral key exchanges.
1410 	 * In this case the ServerKeyExchange message has:
1411 	 * [1 byte CurveType], [2 byte CurveName]
1412 	 * [1 byte length of encoded point], followed by
1413 	 * the actual encoded point itself.
1414 	 */
1415 	if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
1416 		goto err;
1417 	if (!CBB_add_u16(cbb, curve_id))
1418 		goto err;
1419 	if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
1420 		goto err;
1421 	if (!CBB_add_space(&ecpoint, &data, encoded_len))
1422 		goto err;
1423 	if (EC_POINT_point2oct(group, pubkey, POINT_CONVERSION_UNCOMPRESSED,
1424 	    data, encoded_len, bn_ctx) == 0) {
1425 		SSLerror(s, ERR_R_ECDH_LIB);
1426 		goto err;
1427 	}
1428 	if (!CBB_flush(cbb))
1429 		goto err;
1430 
1431 	BN_CTX_free(bn_ctx);
1432 
1433 	return (1);
1434 
1435  f_err:
1436 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1437  err:
1438 	BN_CTX_free(bn_ctx);
1439 
1440 	return (-1);
1441 }
1442 
1443 static int
1444 ssl3_send_server_kex_ecdhe_ecx(SSL *s, int nid, CBB *cbb)
1445 {
1446 	uint8_t *public_key = NULL;
1447 	int curve_id;
1448 	CBB ecpoint;
1449 	int ret = -1;
1450 
1451 	/* Generate an X25519 key pair. */
1452 	if (S3I(s)->tmp.x25519 != NULL) {
1453 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1454 		goto err;
1455 	}
1456 	if ((S3I(s)->tmp.x25519 = malloc(X25519_KEY_LENGTH)) == NULL)
1457 		goto err;
1458 	if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL)
1459 		goto err;
1460 	X25519_keypair(public_key, S3I(s)->tmp.x25519);
1461 
1462 	/* Serialize public key. */
1463 	if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
1464 		SSLerror(s, SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
1465 		goto err;
1466 	}
1467 
1468 	if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
1469 		goto err;
1470 	if (!CBB_add_u16(cbb, curve_id))
1471 		goto err;
1472 	if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
1473 		goto err;
1474 	if (!CBB_add_bytes(&ecpoint, public_key, X25519_KEY_LENGTH))
1475 		goto err;
1476 	if (!CBB_flush(cbb))
1477 		goto err;
1478 
1479 	ret = 1;
1480 
1481  err:
1482 	free(public_key);
1483 
1484 	return (ret);
1485 }
1486 
1487 static int
1488 ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
1489 {
1490 	int nid;
1491 
1492 	nid = tls1_get_shared_curve(s);
1493 
1494 	if (nid == NID_X25519)
1495 		return ssl3_send_server_kex_ecdhe_ecx(s, nid, cbb);
1496 
1497 	return ssl3_send_server_kex_ecdhe_ecp(s, nid, cbb);
1498 }
1499 
1500 int
1501 ssl3_send_server_key_exchange(SSL *s)
1502 {
1503 	CBB cbb;
1504 	unsigned char *params = NULL;
1505 	size_t params_len;
1506 	unsigned char *q;
1507 	unsigned char md_buf[MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH];
1508 	unsigned int u;
1509 	EVP_PKEY *pkey;
1510 	const EVP_MD *md = NULL;
1511 	unsigned char *p, *d;
1512 	int al, i, j, n, kn;
1513 	unsigned long type;
1514 	BUF_MEM *buf;
1515 	EVP_MD_CTX md_ctx;
1516 
1517 	memset(&cbb, 0, sizeof(cbb));
1518 
1519 	EVP_MD_CTX_init(&md_ctx);
1520 	if (S3I(s)->hs.state == SSL3_ST_SW_KEY_EXCH_A) {
1521 		type = S3I(s)->hs.new_cipher->algorithm_mkey;
1522 
1523 		buf = s->internal->init_buf;
1524 
1525 		if (!CBB_init(&cbb, 0))
1526 			goto err;
1527 
1528 		if (type & SSL_kDHE) {
1529 			if (ssl3_send_server_kex_dhe(s, &cbb) != 1)
1530 				goto err;
1531 		} else if (type & SSL_kECDHE) {
1532 			if (ssl3_send_server_kex_ecdhe(s, &cbb) != 1)
1533 				goto err;
1534 		} else {
1535 			al = SSL_AD_HANDSHAKE_FAILURE;
1536 			SSLerror(s, SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
1537 			goto f_err;
1538 		}
1539 
1540 		if (!CBB_finish(&cbb, &params, &params_len))
1541 			goto err;
1542 
1543 		if (!(S3I(s)->hs.new_cipher->algorithm_auth & SSL_aNULL)) {
1544 			if ((pkey = ssl_get_sign_pkey(
1545 			    s, S3I(s)->hs.new_cipher, &md)) == NULL) {
1546 				al = SSL_AD_DECODE_ERROR;
1547 				goto f_err;
1548 			}
1549 			kn = EVP_PKEY_size(pkey);
1550 		} else {
1551 			pkey = NULL;
1552 			kn = 0;
1553 		}
1554 
1555 		if (!BUF_MEM_grow_clean(buf, ssl3_handshake_msg_hdr_len(s) +
1556 		    params_len + kn)) {
1557 			SSLerror(s, ERR_LIB_BUF);
1558 			goto err;
1559 		}
1560 
1561 		d = p = ssl3_handshake_msg_start(s,
1562 		    SSL3_MT_SERVER_KEY_EXCHANGE);
1563 
1564 		memcpy(p, params, params_len);
1565 
1566 		free(params);
1567 		params = NULL;
1568 
1569 		n = params_len;
1570 		p += params_len;
1571 
1572 		/* not anonymous */
1573 		if (pkey != NULL) {
1574 			/*
1575 			 * n is the length of the params, they start at &(d[4])
1576 			 * and p points to the space at the end.
1577 			 */
1578 			if (pkey->type == EVP_PKEY_RSA && !SSL_USE_SIGALGS(s)) {
1579 				q = md_buf;
1580 				j = 0;
1581 				if (!EVP_DigestInit_ex(&md_ctx, EVP_md5_sha1(),
1582 				    NULL))
1583 					goto err;
1584 				EVP_DigestUpdate(&md_ctx, s->s3->client_random,
1585 				    SSL3_RANDOM_SIZE);
1586 				EVP_DigestUpdate(&md_ctx, s->s3->server_random,
1587 				    SSL3_RANDOM_SIZE);
1588 				EVP_DigestUpdate(&md_ctx, d, n);
1589 				EVP_DigestFinal_ex(&md_ctx, q,
1590 				    (unsigned int *)&i);
1591 				q += i;
1592 				j += i;
1593 				if (RSA_sign(NID_md5_sha1, md_buf, j,
1594 				    &(p[2]), &u, pkey->pkey.rsa) <= 0) {
1595 					SSLerror(s, ERR_R_RSA_LIB);
1596 					goto err;
1597 				}
1598 				s2n(u, p);
1599 				n += u + 2;
1600 			} else if (md) {
1601 				/* Send signature algorithm. */
1602 				if (SSL_USE_SIGALGS(s)) {
1603 					if (!tls12_get_sigandhash(p, pkey, md)) {
1604 						/* Should never happen */
1605 						al = SSL_AD_INTERNAL_ERROR;
1606 						SSLerror(s, ERR_R_INTERNAL_ERROR);
1607 						goto f_err;
1608 					}
1609 					p += 2;
1610 				}
1611 				EVP_SignInit_ex(&md_ctx, md, NULL);
1612 				EVP_SignUpdate(&md_ctx,
1613 				    s->s3->client_random,
1614 				    SSL3_RANDOM_SIZE);
1615 				EVP_SignUpdate(&md_ctx,
1616 				    s->s3->server_random,
1617 				    SSL3_RANDOM_SIZE);
1618 				EVP_SignUpdate(&md_ctx, d, n);
1619 				if (!EVP_SignFinal(&md_ctx, &p[2],
1620 					(unsigned int *)&i, pkey)) {
1621 					SSLerror(s, ERR_R_EVP_LIB);
1622 					goto err;
1623 				}
1624 				s2n(i, p);
1625 				n += i + 2;
1626 				if (SSL_USE_SIGALGS(s))
1627 					n += 2;
1628 			} else {
1629 				/* Is this error check actually needed? */
1630 				al = SSL_AD_HANDSHAKE_FAILURE;
1631 				SSLerror(s, SSL_R_UNKNOWN_PKEY_TYPE);
1632 				goto f_err;
1633 			}
1634 		}
1635 
1636 		ssl3_handshake_msg_finish(s, n);
1637 	}
1638 
1639 	S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_B;
1640 
1641 	EVP_MD_CTX_cleanup(&md_ctx);
1642 
1643 	return (ssl3_handshake_write(s));
1644 
1645  f_err:
1646 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1647  err:
1648 	free(params);
1649 	EVP_MD_CTX_cleanup(&md_ctx);
1650 	CBB_cleanup(&cbb);
1651 
1652 	return (-1);
1653 }
1654 
1655 int
1656 ssl3_send_certificate_request(SSL *s)
1657 {
1658 	CBB cbb, cert_request, cert_types, sigalgs, cert_auth, dn;
1659 	STACK_OF(X509_NAME) *sk = NULL;
1660 	X509_NAME *name;
1661 	int i;
1662 
1663 	/*
1664 	 * Certificate Request - RFC 5246 section 7.4.4.
1665 	 */
1666 
1667 	memset(&cbb, 0, sizeof(cbb));
1668 
1669 	if (S3I(s)->hs.state == SSL3_ST_SW_CERT_REQ_A) {
1670 		if (!ssl3_handshake_msg_start_cbb(s, &cbb, &cert_request,
1671 		    SSL3_MT_CERTIFICATE_REQUEST))
1672 			goto err;
1673 
1674 		if (!CBB_add_u8_length_prefixed(&cert_request, &cert_types))
1675 			goto err;
1676 		if (!ssl3_get_req_cert_types(s, &cert_types))
1677 			goto err;
1678 
1679 		if (SSL_USE_SIGALGS(s)) {
1680 			unsigned char *sigalgs_data;
1681 			size_t sigalgs_len;
1682 
1683 			tls12_get_req_sig_algs(s, &sigalgs_data, &sigalgs_len);
1684 
1685 			if (!CBB_add_u16_length_prefixed(&cert_request, &sigalgs))
1686 				goto err;
1687 			if (!CBB_add_bytes(&sigalgs, sigalgs_data, sigalgs_len))
1688 				goto err;
1689 		}
1690 
1691 		if (!CBB_add_u16_length_prefixed(&cert_request, &cert_auth))
1692 			goto err;
1693 
1694 		sk = SSL_get_client_CA_list(s);
1695 		for (i = 0; i < sk_X509_NAME_num(sk); i++) {
1696 			unsigned char *name_data;
1697 			size_t name_len;
1698 
1699 			name = sk_X509_NAME_value(sk, i);
1700 			name_len = i2d_X509_NAME(name, NULL);
1701 
1702 			if (!CBB_add_u16_length_prefixed(&cert_auth, &dn))
1703 				goto err;
1704 			if (!CBB_add_space(&dn, &name_data, name_len))
1705 				goto err;
1706 			if (i2d_X509_NAME(name, &name_data) != name_len)
1707 				goto err;
1708 		}
1709 
1710 		if (!ssl3_handshake_msg_finish_cbb(s, &cbb))
1711 			goto err;
1712 
1713 		S3I(s)->hs.state = SSL3_ST_SW_CERT_REQ_B;
1714 	}
1715 
1716 	/* SSL3_ST_SW_CERT_REQ_B */
1717 	return (ssl3_handshake_write(s));
1718 
1719  err:
1720 	CBB_cleanup(&cbb);
1721 
1722 	return (-1);
1723 }
1724 
1725 static int
1726 ssl3_get_client_kex_rsa(SSL *s, unsigned char *p, long n)
1727 {
1728 	unsigned char fakekey[SSL_MAX_MASTER_KEY_LENGTH];
1729 	unsigned char *d;
1730 	RSA *rsa = NULL;
1731 	EVP_PKEY *pkey = NULL;
1732 	int i, al;
1733 
1734 	d = p;
1735 
1736 	arc4random_buf(fakekey, sizeof(fakekey));
1737 	fakekey[0] = s->client_version >> 8;
1738 	fakekey[1] = s->client_version & 0xff;
1739 
1740 	pkey = s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey;
1741 	if ((pkey == NULL) || (pkey->type != EVP_PKEY_RSA) ||
1742 	    (pkey->pkey.rsa == NULL)) {
1743 		al = SSL_AD_HANDSHAKE_FAILURE;
1744 		SSLerror(s, SSL_R_MISSING_RSA_CERTIFICATE);
1745 		goto f_err;
1746 	}
1747 	rsa = pkey->pkey.rsa;
1748 
1749 	if (2 > n)
1750 		goto truncated;
1751 	n2s(p, i);
1752 	if (n != i + 2) {
1753 		SSLerror(s, SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG);
1754 		goto err;
1755 	} else
1756 		n = i;
1757 
1758 	i = RSA_private_decrypt((int)n, p, p, rsa, RSA_PKCS1_PADDING);
1759 
1760 	ERR_clear_error();
1761 
1762 	al = -1;
1763 
1764 	if (i != SSL_MAX_MASTER_KEY_LENGTH) {
1765 		al = SSL_AD_DECODE_ERROR;
1766 		/* SSLerror(s, SSL_R_BAD_RSA_DECRYPT); */
1767 	}
1768 
1769 	if (p - d + 2 > n)	/* needed in the SSL3 case */
1770 		goto truncated;
1771 	if ((al == -1) && !((p[0] == (s->client_version >> 8)) &&
1772 	    (p[1] == (s->client_version & 0xff)))) {
1773 		/*
1774 		 * The premaster secret must contain the same version
1775 		 * number as the ClientHello to detect version rollback
1776 		 * attacks (strangely, the protocol does not offer such
1777 		 * protection for DH ciphersuites).
1778 		 * However, buggy clients exist that send the negotiated
1779 		 * protocol version instead if the server does not
1780 		 * support the requested protocol version.
1781 		 * If SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such
1782 		 * clients.
1783 		 */
1784 		if (!((s->internal->options & SSL_OP_TLS_ROLLBACK_BUG) &&
1785 		    (p[0] == (s->version >> 8)) &&
1786 		    (p[1] == (s->version & 0xff)))) {
1787 			al = SSL_AD_DECODE_ERROR;
1788 			/* SSLerror(s, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); */
1789 
1790 			/*
1791 			 * The Klima-Pokorny-Rosa extension of
1792 			 * Bleichenbacher's attack
1793 			 * (http://eprint.iacr.org/2003/052/) exploits
1794 			 * the version number check as a "bad version
1795 			 * oracle" -- an alert would reveal that the
1796 			 * plaintext corresponding to some ciphertext
1797 			 * made up by the adversary is properly
1798 			 * formatted except that the version number is
1799 			 * wrong.
1800 			 * To avoid such attacks, we should treat this
1801 			 * just like any other decryption error.
1802 			 */
1803 		}
1804 	}
1805 
1806 	if (al != -1) {
1807 		/*
1808 		 * Some decryption failure -- use random value instead
1809 		 * as countermeasure against Bleichenbacher's attack
1810 		 * on PKCS #1 v1.5 RSA padding (see RFC 2246,
1811 		 * section 7.4.7.1).
1812 		 */
1813 		i = SSL_MAX_MASTER_KEY_LENGTH;
1814 		p = fakekey;
1815 	}
1816 
1817 	s->session->master_key_length =
1818 	    tls1_generate_master_secret(s,
1819 	        s->session->master_key, p, i);
1820 
1821 	explicit_bzero(p, i);
1822 
1823 	return (1);
1824 truncated:
1825 	al = SSL_AD_DECODE_ERROR;
1826 	SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1827 f_err:
1828 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1829 err:
1830 	return (-1);
1831 }
1832 
1833 static int
1834 ssl3_get_client_kex_dhe(SSL *s, unsigned char *p, long n)
1835 {
1836 	BIGNUM *bn = NULL;
1837 	int key_size, al;
1838 	CBS cbs, dh_Yc;
1839 	DH *dh;
1840 
1841 	if (n < 0)
1842 		goto err;
1843 
1844 	CBS_init(&cbs, p, n);
1845 
1846 	if (!CBS_get_u16_length_prefixed(&cbs, &dh_Yc))
1847 		goto truncated;
1848 
1849 	if (CBS_len(&cbs) != 0)
1850 		goto truncated;
1851 
1852 	if (S3I(s)->tmp.dh == NULL) {
1853 		al = SSL_AD_HANDSHAKE_FAILURE;
1854 		SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
1855 		goto f_err;
1856 	}
1857 	dh = S3I(s)->tmp.dh;
1858 
1859 	if ((bn = BN_bin2bn(CBS_data(&dh_Yc), CBS_len(&dh_Yc), NULL)) == NULL) {
1860 		SSLerror(s, SSL_R_BN_LIB);
1861 		goto err;
1862 	}
1863 
1864 	key_size = DH_compute_key(p, bn, dh);
1865 	if (key_size <= 0) {
1866 		SSLerror(s, ERR_R_DH_LIB);
1867 		BN_clear_free(bn);
1868 		goto err;
1869 	}
1870 
1871 	s->session->master_key_length =
1872 	    tls1_generate_master_secret(
1873 	        s, s->session->master_key, p, key_size);
1874 
1875 	explicit_bzero(p, key_size);
1876 
1877 	DH_free(S3I(s)->tmp.dh);
1878 	S3I(s)->tmp.dh = NULL;
1879 
1880 	BN_clear_free(bn);
1881 
1882 	return (1);
1883 
1884  truncated:
1885 	al = SSL_AD_DECODE_ERROR;
1886 	SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1887  f_err:
1888 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1889  err:
1890 	return (-1);
1891 }
1892 
1893 static int
1894 ssl3_get_client_kex_ecdhe_ecp(SSL *s, unsigned char *p, long n)
1895 {
1896 	EC_KEY *srvr_ecdh = NULL;
1897 	EVP_PKEY *clnt_pub_pkey = NULL;
1898 	EC_POINT *clnt_ecpoint = NULL;
1899 	BN_CTX *bn_ctx = NULL;
1900 	int i, al;
1901 
1902 	int ret = 1;
1903 	int key_size;
1904 	const EC_KEY   *tkey;
1905 	const EC_GROUP *group;
1906 	const BIGNUM *priv_key;
1907 
1908 	/* Initialize structures for server's ECDH key pair. */
1909 	if ((srvr_ecdh = EC_KEY_new()) == NULL) {
1910 		SSLerror(s, ERR_R_MALLOC_FAILURE);
1911 		goto err;
1912 	}
1913 
1914 	/*
1915 	 * Use the ephemeral values we saved when
1916 	 * generating the ServerKeyExchange message.
1917 	 */
1918 	tkey = S3I(s)->tmp.ecdh;
1919 
1920 	group = EC_KEY_get0_group(tkey);
1921 	priv_key = EC_KEY_get0_private_key(tkey);
1922 
1923 	if (!EC_KEY_set_group(srvr_ecdh, group) ||
1924 	    !EC_KEY_set_private_key(srvr_ecdh, priv_key)) {
1925 		SSLerror(s, ERR_R_EC_LIB);
1926 		goto err;
1927 	}
1928 
1929 	/* Let's get client's public key */
1930 	if ((clnt_ecpoint = EC_POINT_new(group)) == NULL) {
1931 		SSLerror(s, ERR_R_MALLOC_FAILURE);
1932 		goto err;
1933 	}
1934 
1935 	if (n == 0L) {
1936 		/* Client Publickey was in Client Certificate */
1937 		if (((clnt_pub_pkey = X509_get_pubkey(
1938 		    s->session->peer)) == NULL) ||
1939 		    (clnt_pub_pkey->type != EVP_PKEY_EC)) {
1940 			/*
1941 			 * XXX: For now, we do not support client
1942 			 * authentication using ECDH certificates
1943 			 * so this branch (n == 0L) of the code is
1944 			 * never executed. When that support is
1945 			 * added, we ought to ensure the key
1946 			 * received in the certificate is
1947 			 * authorized for key agreement.
1948 			 * ECDH_compute_key implicitly checks that
1949 			 * the two ECDH shares are for the same
1950 			 * group.
1951 			 */
1952 			al = SSL_AD_HANDSHAKE_FAILURE;
1953 			SSLerror(s, SSL_R_UNABLE_TO_DECODE_ECDH_CERTS);
1954 			goto f_err;
1955 		}
1956 
1957 		if (EC_POINT_copy(clnt_ecpoint,
1958 		    EC_KEY_get0_public_key(clnt_pub_pkey->pkey.ec))
1959 		    == 0) {
1960 			SSLerror(s, ERR_R_EC_LIB);
1961 			goto err;
1962 		}
1963 		ret = 2; /* Skip certificate verify processing */
1964 	} else {
1965 		/*
1966 		 * Get client's public key from encoded point
1967 		 * in the ClientKeyExchange message.
1968 		 */
1969 		if ((bn_ctx = BN_CTX_new()) == NULL) {
1970 			SSLerror(s, ERR_R_MALLOC_FAILURE);
1971 			goto err;
1972 		}
1973 
1974 		/* Get encoded point length */
1975 		i = *p;
1976 
1977 		p += 1;
1978 		if (n != 1 + i) {
1979 			SSLerror(s, ERR_R_EC_LIB);
1980 			goto err;
1981 		}
1982 		if (EC_POINT_oct2point(group,
1983 			clnt_ecpoint, p, i, bn_ctx) == 0) {
1984 			SSLerror(s, ERR_R_EC_LIB);
1985 			goto err;
1986 		}
1987 		/*
1988 		 * p is pointing to somewhere in the buffer
1989 		 * currently, so set it to the start.
1990 		 */
1991 		p = (unsigned char *)s->internal->init_buf->data;
1992 	}
1993 
1994 	/* Compute the shared pre-master secret */
1995 	key_size = ECDH_size(srvr_ecdh);
1996 	if (key_size <= 0) {
1997 		SSLerror(s, ERR_R_ECDH_LIB);
1998 		goto err;
1999 	}
2000 	i = ECDH_compute_key(p, key_size, clnt_ecpoint, srvr_ecdh,
2001 	    NULL);
2002 	if (i <= 0) {
2003 		SSLerror(s, ERR_R_ECDH_LIB);
2004 		goto err;
2005 	}
2006 
2007 	EVP_PKEY_free(clnt_pub_pkey);
2008 	EC_POINT_free(clnt_ecpoint);
2009 	EC_KEY_free(srvr_ecdh);
2010 	BN_CTX_free(bn_ctx);
2011 	EC_KEY_free(S3I(s)->tmp.ecdh);
2012 	S3I(s)->tmp.ecdh = NULL;
2013 
2014 	/* Compute the master secret */
2015 	s->session->master_key_length =
2016 	    tls1_generate_master_secret(
2017 		s, s->session->master_key, p, i);
2018 
2019 	explicit_bzero(p, i);
2020 	return (ret);
2021 
2022  f_err:
2023 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
2024  err:
2025 	EVP_PKEY_free(clnt_pub_pkey);
2026 	EC_POINT_free(clnt_ecpoint);
2027 	EC_KEY_free(srvr_ecdh);
2028 	BN_CTX_free(bn_ctx);
2029 	return (-1);
2030 }
2031 
2032 static int
2033 ssl3_get_client_kex_ecdhe_ecx(SSL *s, unsigned char *p, long n)
2034 {
2035 	uint8_t *shared_key = NULL;
2036 	CBS cbs, ecpoint;
2037 	int ret = -1;
2038 
2039 	if (n < 0)
2040 		goto err;
2041 
2042 	CBS_init(&cbs, p, n);
2043 	if (!CBS_get_u8_length_prefixed(&cbs, &ecpoint))
2044 		goto err;
2045 	if (CBS_len(&ecpoint) != X25519_KEY_LENGTH)
2046 		goto err;
2047 
2048 	if ((shared_key = malloc(X25519_KEY_LENGTH)) == NULL)
2049 		goto err;
2050 	if (!X25519(shared_key, S3I(s)->tmp.x25519, CBS_data(&ecpoint)))
2051 		goto err;
2052 
2053 	freezero(S3I(s)->tmp.x25519, X25519_KEY_LENGTH);
2054 	S3I(s)->tmp.x25519 = NULL;
2055 
2056 	s->session->master_key_length =
2057 	    tls1_generate_master_secret(
2058 		s, s->session->master_key, shared_key, X25519_KEY_LENGTH);
2059 
2060 	ret = 1;
2061 
2062  err:
2063 	freezero(shared_key, X25519_KEY_LENGTH);
2064 
2065 	return (ret);
2066 }
2067 
2068 static int
2069 ssl3_get_client_kex_ecdhe(SSL *s, unsigned char *p, long n)
2070 {
2071         if (S3I(s)->tmp.x25519 != NULL)
2072 		return ssl3_get_client_kex_ecdhe_ecx(s, p, n);
2073 
2074 	return ssl3_get_client_kex_ecdhe_ecp(s, p, n);
2075 }
2076 
2077 static int
2078 ssl3_get_client_kex_gost(SSL *s, unsigned char *p, long n)
2079 {
2080 
2081 	EVP_PKEY_CTX *pkey_ctx;
2082 	EVP_PKEY *client_pub_pkey = NULL, *pk = NULL;
2083 	unsigned char premaster_secret[32], *start;
2084 	size_t outlen = 32, inlen;
2085 	unsigned long alg_a;
2086 	int Ttag, Tclass;
2087 	long Tlen;
2088 	int al;
2089 	int ret = 0;
2090 
2091 	/* Get our certificate private key*/
2092 	alg_a = S3I(s)->hs.new_cipher->algorithm_auth;
2093 	if (alg_a & SSL_aGOST01)
2094 		pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
2095 
2096 	pkey_ctx = EVP_PKEY_CTX_new(pk, NULL);
2097 	EVP_PKEY_decrypt_init(pkey_ctx);
2098 	/*
2099 	 * If client certificate is present and is of the same type,
2100 	 * maybe use it for key exchange.
2101 	 * Don't mind errors from EVP_PKEY_derive_set_peer, because
2102 	 * it is completely valid to use a client certificate for
2103 	 * authorization only.
2104 	 */
2105 	client_pub_pkey = X509_get_pubkey(s->session->peer);
2106 	if (client_pub_pkey) {
2107 		if (EVP_PKEY_derive_set_peer(pkey_ctx,
2108 		    client_pub_pkey) <= 0)
2109 			ERR_clear_error();
2110 	}
2111 	if (2 > n)
2112 		goto truncated;
2113 	/* Decrypt session key */
2114 	if (ASN1_get_object((const unsigned char **)&p, &Tlen, &Ttag,
2115 	    &Tclass, n) != V_ASN1_CONSTRUCTED ||
2116 	    Ttag != V_ASN1_SEQUENCE || Tclass != V_ASN1_UNIVERSAL) {
2117 		SSLerror(s, SSL_R_DECRYPTION_FAILED);
2118 		goto gerr;
2119 	}
2120 	start = p;
2121 	inlen = Tlen;
2122 	if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen,
2123 	    start, inlen) <=0) {
2124 		SSLerror(s, SSL_R_DECRYPTION_FAILED);
2125 		goto gerr;
2126 	}
2127 	/* Generate master secret */
2128 	s->session->master_key_length =
2129 	    tls1_generate_master_secret(
2130 		s, s->session->master_key, premaster_secret, 32);
2131 	/* Check if pubkey from client certificate was used */
2132 	if (EVP_PKEY_CTX_ctrl(pkey_ctx, -1, -1,
2133 	    EVP_PKEY_CTRL_PEER_KEY, 2, NULL) > 0)
2134 		ret = 2;
2135 	else
2136 		ret = 1;
2137  gerr:
2138 	EVP_PKEY_free(client_pub_pkey);
2139 	EVP_PKEY_CTX_free(pkey_ctx);
2140 	if (ret)
2141 		return (ret);
2142 	else
2143 		goto err;
2144 
2145  truncated:
2146 	al = SSL_AD_DECODE_ERROR;
2147 	SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2148 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
2149  err:
2150 	return (-1);
2151 }
2152 
2153 int
2154 ssl3_get_client_key_exchange(SSL *s)
2155 {
2156 	unsigned long alg_k;
2157 	unsigned char *p;
2158 	int al, ok;
2159 	long n;
2160 
2161 	/* 2048 maxlen is a guess.  How long a key does that permit? */
2162 	n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_KEY_EXCH_A,
2163 	    SSL3_ST_SR_KEY_EXCH_B, SSL3_MT_CLIENT_KEY_EXCHANGE, 2048, &ok);
2164 	if (!ok)
2165 		return ((int)n);
2166 
2167 	p = (unsigned char *)s->internal->init_msg;
2168 
2169 	alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
2170 
2171 	if (alg_k & SSL_kRSA) {
2172 		if (ssl3_get_client_kex_rsa(s, p, n) != 1)
2173 			goto err;
2174 	} else if (alg_k & SSL_kDHE) {
2175 		if (ssl3_get_client_kex_dhe(s, p, n) != 1)
2176 			goto err;
2177 	} else if (alg_k & SSL_kECDHE) {
2178 		if (ssl3_get_client_kex_ecdhe(s, p, n) != 1)
2179 			goto err;
2180 	} else if (alg_k & SSL_kGOST) {
2181 		if (ssl3_get_client_kex_gost(s, p, n) != 1)
2182 			goto err;
2183 	} else {
2184 		al = SSL_AD_HANDSHAKE_FAILURE;
2185 		SSLerror(s, SSL_R_UNKNOWN_CIPHER_TYPE);
2186 		goto f_err;
2187 	}
2188 
2189 	return (1);
2190 
2191  f_err:
2192 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
2193  err:
2194 	return (-1);
2195 }
2196 
2197 int
2198 ssl3_get_cert_verify(SSL *s)
2199 {
2200 	EVP_PKEY *pkey = NULL;
2201 	unsigned char *p;
2202 	int al, ok, ret = 0;
2203 	long n;
2204 	int type = 0, i, j;
2205 	X509 *peer;
2206 	const EVP_MD *md = NULL;
2207 	EVP_MD_CTX mctx;
2208 	EVP_MD_CTX_init(&mctx);
2209 
2210 	n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_CERT_VRFY_A,
2211 	    SSL3_ST_SR_CERT_VRFY_B, -1, SSL3_RT_MAX_PLAIN_LENGTH, &ok);
2212 	if (!ok)
2213 		return ((int)n);
2214 
2215 	if (s->session->peer != NULL) {
2216 		peer = s->session->peer;
2217 		pkey = X509_get_pubkey(peer);
2218 		type = X509_certificate_type(peer, pkey);
2219 	} else {
2220 		peer = NULL;
2221 		pkey = NULL;
2222 	}
2223 
2224 	if (S3I(s)->tmp.message_type != SSL3_MT_CERTIFICATE_VERIFY) {
2225 		S3I(s)->tmp.reuse_message = 1;
2226 		if (peer != NULL) {
2227 			al = SSL_AD_UNEXPECTED_MESSAGE;
2228 			SSLerror(s, SSL_R_MISSING_VERIFY_MESSAGE);
2229 			goto f_err;
2230 		}
2231 		ret = 1;
2232 		goto end;
2233 	}
2234 
2235 	if (peer == NULL) {
2236 		SSLerror(s, SSL_R_NO_CLIENT_CERT_RECEIVED);
2237 		al = SSL_AD_UNEXPECTED_MESSAGE;
2238 		goto f_err;
2239 	}
2240 
2241 	if (!(type & EVP_PKT_SIGN)) {
2242 		SSLerror(s, SSL_R_SIGNATURE_FOR_NON_SIGNING_CERTIFICATE);
2243 		al = SSL_AD_ILLEGAL_PARAMETER;
2244 		goto f_err;
2245 	}
2246 
2247 	if (S3I(s)->change_cipher_spec) {
2248 		SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
2249 		al = SSL_AD_UNEXPECTED_MESSAGE;
2250 		goto f_err;
2251 	}
2252 
2253 	/* we now have a signature that we need to verify */
2254 	p = (unsigned char *)s->internal->init_msg;
2255 	/*
2256 	 * Check for broken implementations of GOST ciphersuites.
2257 	 *
2258 	 * If key is GOST and n is exactly 64, it is a bare
2259 	 * signature without length field.
2260 	 */
2261 	if (n == 64 && (pkey->type == NID_id_GostR3410_94 ||
2262 	    pkey->type == NID_id_GostR3410_2001) ) {
2263 		i = 64;
2264 	} else {
2265 		if (SSL_USE_SIGALGS(s)) {
2266 			int sigalg = tls12_get_sigid(pkey);
2267 			/* Should never happen */
2268 			if (sigalg == -1) {
2269 				SSLerror(s, ERR_R_INTERNAL_ERROR);
2270 				al = SSL_AD_INTERNAL_ERROR;
2271 				goto f_err;
2272 			}
2273 			if (2 > n)
2274 				goto truncated;
2275 			/* Check key type is consistent with signature */
2276 			if (sigalg != (int)p[1]) {
2277 				SSLerror(s, SSL_R_WRONG_SIGNATURE_TYPE);
2278 				al = SSL_AD_DECODE_ERROR;
2279 				goto f_err;
2280 			}
2281 			md = tls12_get_hash(p[0]);
2282 			if (md == NULL) {
2283 				SSLerror(s, SSL_R_UNKNOWN_DIGEST);
2284 				al = SSL_AD_DECODE_ERROR;
2285 				goto f_err;
2286 			}
2287 			p += 2;
2288 			n -= 2;
2289 		}
2290 		if (2 > n)
2291 			goto truncated;
2292 		n2s(p, i);
2293 		n -= 2;
2294 		if (i > n)
2295 			goto truncated;
2296 	}
2297 	j = EVP_PKEY_size(pkey);
2298 	if ((i > j) || (n > j) || (n <= 0)) {
2299 		SSLerror(s, SSL_R_WRONG_SIGNATURE_SIZE);
2300 		al = SSL_AD_DECODE_ERROR;
2301 		goto f_err;
2302 	}
2303 
2304 	if (SSL_USE_SIGALGS(s)) {
2305 		long hdatalen = 0;
2306 		void *hdata;
2307 		hdatalen = BIO_get_mem_data(S3I(s)->handshake_buffer, &hdata);
2308 		if (hdatalen <= 0) {
2309 			SSLerror(s, ERR_R_INTERNAL_ERROR);
2310 			al = SSL_AD_INTERNAL_ERROR;
2311 			goto f_err;
2312 		}
2313 		if (!EVP_VerifyInit_ex(&mctx, md, NULL) ||
2314 		    !EVP_VerifyUpdate(&mctx, hdata, hdatalen)) {
2315 			SSLerror(s, ERR_R_EVP_LIB);
2316 			al = SSL_AD_INTERNAL_ERROR;
2317 			goto f_err;
2318 		}
2319 
2320 		if (EVP_VerifyFinal(&mctx, p, i, pkey) <= 0) {
2321 			al = SSL_AD_DECRYPT_ERROR;
2322 			SSLerror(s, SSL_R_BAD_SIGNATURE);
2323 			goto f_err;
2324 		}
2325 	} else
2326 	if (pkey->type == EVP_PKEY_RSA) {
2327 		i = RSA_verify(NID_md5_sha1, S3I(s)->tmp.cert_verify_md,
2328 		    MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH, p, i,
2329 		    pkey->pkey.rsa);
2330 		if (i < 0) {
2331 			al = SSL_AD_DECRYPT_ERROR;
2332 			SSLerror(s, SSL_R_BAD_RSA_DECRYPT);
2333 			goto f_err;
2334 		}
2335 		if (i == 0) {
2336 			al = SSL_AD_DECRYPT_ERROR;
2337 			SSLerror(s, SSL_R_BAD_RSA_SIGNATURE);
2338 			goto f_err;
2339 		}
2340 	} else
2341 	if (pkey->type == EVP_PKEY_EC) {
2342 		j = ECDSA_verify(pkey->save_type,
2343 		    &(S3I(s)->tmp.cert_verify_md[MD5_DIGEST_LENGTH]),
2344 		    SHA_DIGEST_LENGTH, p, i, pkey->pkey.ec);
2345 		if (j <= 0) {
2346 			/* bad signature */
2347 			al = SSL_AD_DECRYPT_ERROR;
2348 			SSLerror(s, SSL_R_BAD_ECDSA_SIGNATURE);
2349 			goto f_err;
2350 		}
2351 	} else
2352 #ifndef OPENSSL_NO_GOST
2353 	if (pkey->type == NID_id_GostR3410_94 ||
2354 	    pkey->type == NID_id_GostR3410_2001) {
2355 		long hdatalen = 0;
2356 		void *hdata;
2357 		unsigned char signature[128];
2358 		unsigned int siglen = sizeof(signature);
2359 		int nid;
2360 		EVP_PKEY_CTX *pctx;
2361 
2362 		hdatalen = BIO_get_mem_data(S3I(s)->handshake_buffer, &hdata);
2363 		if (hdatalen <= 0) {
2364 			SSLerror(s, ERR_R_INTERNAL_ERROR);
2365 			al = SSL_AD_INTERNAL_ERROR;
2366 			goto f_err;
2367 		}
2368 		if (!EVP_PKEY_get_default_digest_nid(pkey, &nid) ||
2369 				!(md = EVP_get_digestbynid(nid))) {
2370 			SSLerror(s, ERR_R_EVP_LIB);
2371 			al = SSL_AD_INTERNAL_ERROR;
2372 			goto f_err;
2373 		}
2374 		pctx = EVP_PKEY_CTX_new(pkey, NULL);
2375 		if (!pctx) {
2376 			SSLerror(s, ERR_R_EVP_LIB);
2377 			al = SSL_AD_INTERNAL_ERROR;
2378 			goto f_err;
2379 		}
2380 		if (!EVP_DigestInit_ex(&mctx, md, NULL) ||
2381 		    !EVP_DigestUpdate(&mctx, hdata, hdatalen) ||
2382 		    !EVP_DigestFinal(&mctx, signature, &siglen) ||
2383 		    (EVP_PKEY_verify_init(pctx) <= 0) ||
2384 		    (EVP_PKEY_CTX_set_signature_md(pctx, md) <= 0) ||
2385 		    (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_VERIFY,
2386 				       EVP_PKEY_CTRL_GOST_SIG_FORMAT,
2387 				       GOST_SIG_FORMAT_RS_LE,
2388 				       NULL) <= 0)) {
2389 			SSLerror(s, ERR_R_EVP_LIB);
2390 			al = SSL_AD_INTERNAL_ERROR;
2391 			EVP_PKEY_CTX_free(pctx);
2392 			goto f_err;
2393 		}
2394 
2395 		if (EVP_PKEY_verify(pctx, p, i, signature, siglen) <= 0) {
2396 			al = SSL_AD_DECRYPT_ERROR;
2397 			SSLerror(s, SSL_R_BAD_SIGNATURE);
2398 			EVP_PKEY_CTX_free(pctx);
2399 			goto f_err;
2400 		}
2401 
2402 		EVP_PKEY_CTX_free(pctx);
2403 	} else
2404 #endif
2405 	{
2406 		SSLerror(s, ERR_R_INTERNAL_ERROR);
2407 		al = SSL_AD_UNSUPPORTED_CERTIFICATE;
2408 		goto f_err;
2409 	}
2410 
2411 
2412 	ret = 1;
2413 	if (0) {
2414 truncated:
2415 		al = SSL_AD_DECODE_ERROR;
2416 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2417 f_err:
2418 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
2419 	}
2420 end:
2421 	if (S3I(s)->handshake_buffer) {
2422 		BIO_free(S3I(s)->handshake_buffer);
2423 		S3I(s)->handshake_buffer = NULL;
2424 		s->s3->flags &= ~TLS1_FLAGS_KEEP_HANDSHAKE;
2425 	}
2426 	EVP_MD_CTX_cleanup(&mctx);
2427 	EVP_PKEY_free(pkey);
2428 	return (ret);
2429 }
2430 
2431 int
2432 ssl3_get_client_certificate(SSL *s)
2433 {
2434 	CBS cbs, client_certs;
2435 	int i, ok, al, ret = -1;
2436 	X509 *x = NULL;
2437 	long n;
2438 	const unsigned char *q;
2439 	STACK_OF(X509) *sk = NULL;
2440 
2441 	n = s->method->internal->ssl_get_message(s, SSL3_ST_SR_CERT_A, SSL3_ST_SR_CERT_B,
2442 	    -1, s->internal->max_cert_list, &ok);
2443 
2444 	if (!ok)
2445 		return ((int)n);
2446 
2447 	if (S3I(s)->tmp.message_type == SSL3_MT_CLIENT_KEY_EXCHANGE) {
2448 		if ((s->verify_mode & SSL_VERIFY_PEER) &&
2449 		    (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
2450 		    	SSLerror(s, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
2451 			al = SSL_AD_HANDSHAKE_FAILURE;
2452 			goto f_err;
2453 		}
2454 		/*
2455 		 * If tls asked for a client cert,
2456 		 * the client must return a 0 list.
2457 		 */
2458 		if (S3I(s)->tmp.cert_request) {
2459 			SSLerror(s, SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST
2460 			    );
2461 			al = SSL_AD_UNEXPECTED_MESSAGE;
2462 			goto f_err;
2463 		}
2464 		S3I(s)->tmp.reuse_message = 1;
2465 		return (1);
2466 	}
2467 
2468 	if (S3I(s)->tmp.message_type != SSL3_MT_CERTIFICATE) {
2469 		al = SSL_AD_UNEXPECTED_MESSAGE;
2470 		SSLerror(s, SSL_R_WRONG_MESSAGE_TYPE);
2471 		goto f_err;
2472 	}
2473 
2474 	if (n < 0)
2475 		goto truncated;
2476 
2477 	CBS_init(&cbs, s->internal->init_msg, n);
2478 
2479 	if ((sk = sk_X509_new_null()) == NULL) {
2480 		SSLerror(s, ERR_R_MALLOC_FAILURE);
2481 		goto err;
2482 	}
2483 
2484 	if (!CBS_get_u24_length_prefixed(&cbs, &client_certs) ||
2485 	    CBS_len(&cbs) != 0)
2486 		goto truncated;
2487 
2488 	while (CBS_len(&client_certs) > 0) {
2489 		CBS cert;
2490 
2491 		if (!CBS_get_u24_length_prefixed(&client_certs, &cert)) {
2492 			al = SSL_AD_DECODE_ERROR;
2493 			SSLerror(s, SSL_R_CERT_LENGTH_MISMATCH);
2494 			goto f_err;
2495 		}
2496 
2497 		q = CBS_data(&cert);
2498 		x = d2i_X509(NULL, &q, CBS_len(&cert));
2499 		if (x == NULL) {
2500 			SSLerror(s, ERR_R_ASN1_LIB);
2501 			goto err;
2502 		}
2503 		if (q != CBS_data(&cert) + CBS_len(&cert)) {
2504 			al = SSL_AD_DECODE_ERROR;
2505 			SSLerror(s, SSL_R_CERT_LENGTH_MISMATCH);
2506 			goto f_err;
2507 		}
2508 		if (!sk_X509_push(sk, x)) {
2509 			SSLerror(s, ERR_R_MALLOC_FAILURE);
2510 			goto err;
2511 		}
2512 		x = NULL;
2513 	}
2514 
2515 	if (sk_X509_num(sk) <= 0) {
2516 		/*
2517 		 * TLS does not mind 0 certs returned.
2518 		 * Fail for TLS only if we required a certificate.
2519 		 */
2520 		if ((s->verify_mode & SSL_VERIFY_PEER) &&
2521 		    (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
2522 			SSLerror(s, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
2523 			al = SSL_AD_HANDSHAKE_FAILURE;
2524 			goto f_err;
2525 		}
2526 		/* No client certificate so digest cached records */
2527 		if (S3I(s)->handshake_buffer && !tls1_digest_cached_records(s)) {
2528 			al = SSL_AD_INTERNAL_ERROR;
2529 			goto f_err;
2530 		}
2531 	} else {
2532 		i = ssl_verify_cert_chain(s, sk);
2533 		if (i <= 0) {
2534 			al = ssl_verify_alarm_type(s->verify_result);
2535 			SSLerror(s, SSL_R_NO_CERTIFICATE_RETURNED);
2536 			goto f_err;
2537 		}
2538 	}
2539 
2540 	X509_free(s->session->peer);
2541 	s->session->peer = sk_X509_shift(sk);
2542 	s->session->verify_result = s->verify_result;
2543 
2544 	/*
2545 	 * With the current implementation, sess_cert will always be NULL
2546 	 * when we arrive here
2547 	 */
2548 	if (SSI(s)->sess_cert == NULL) {
2549 		SSI(s)->sess_cert = ssl_sess_cert_new();
2550 		if (SSI(s)->sess_cert == NULL) {
2551 			SSLerror(s, ERR_R_MALLOC_FAILURE);
2552 			goto err;
2553 		}
2554 	}
2555 	sk_X509_pop_free(SSI(s)->sess_cert->cert_chain, X509_free);
2556 	SSI(s)->sess_cert->cert_chain = sk;
2557 
2558 	/*
2559 	 * Inconsistency alert: cert_chain does *not* include the
2560 	 * peer's own certificate, while we do include it in s3_clnt.c
2561 	 */
2562 
2563 	sk = NULL;
2564 
2565 	ret = 1;
2566 	if (0) {
2567 truncated:
2568 		al = SSL_AD_DECODE_ERROR;
2569 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2570 f_err:
2571 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
2572 	}
2573 err:
2574 	X509_free(x);
2575 	sk_X509_pop_free(sk, X509_free);
2576 
2577 	return (ret);
2578 }
2579 
2580 int
2581 ssl3_send_server_certificate(SSL *s)
2582 {
2583 	CBB cbb, server_cert;
2584 	X509 *x;
2585 
2586 	/*
2587 	 * Server Certificate - RFC 5246, section 7.4.2.
2588 	 */
2589 
2590 	memset(&cbb, 0, sizeof(cbb));
2591 
2592 	if (S3I(s)->hs.state == SSL3_ST_SW_CERT_A) {
2593 		if ((x = ssl_get_server_send_cert(s)) == NULL) {
2594 			SSLerror(s, ERR_R_INTERNAL_ERROR);
2595 			return (0);
2596 		}
2597 
2598 		if (!ssl3_handshake_msg_start_cbb(s, &cbb, &server_cert,
2599 		    SSL3_MT_CERTIFICATE))
2600 			goto err;
2601 		if (!ssl3_output_cert_chain(s, &server_cert, x))
2602 			goto err;
2603 		if (!ssl3_handshake_msg_finish_cbb(s, &cbb))
2604 			goto err;
2605 
2606 		S3I(s)->hs.state = SSL3_ST_SW_CERT_B;
2607 	}
2608 
2609 	/* SSL3_ST_SW_CERT_B */
2610 	return (ssl3_handshake_write(s));
2611 
2612  err:
2613 	CBB_cleanup(&cbb);
2614 
2615 	return (0);
2616 }
2617 
2618 /* send a new session ticket (not necessarily for a new session) */
2619 int
2620 ssl3_send_newsession_ticket(SSL *s)
2621 {
2622 	unsigned char *d, *p, *macstart;
2623 	unsigned char *senc = NULL;
2624 	const unsigned char *const_p;
2625 	int len, slen_full, slen;
2626 	SSL_SESSION *sess;
2627 	unsigned int hlen;
2628 	EVP_CIPHER_CTX ctx;
2629 	HMAC_CTX hctx;
2630 	SSL_CTX *tctx = s->initial_ctx;
2631 	unsigned char iv[EVP_MAX_IV_LENGTH];
2632 	unsigned char key_name[16];
2633 
2634 	if (S3I(s)->hs.state == SSL3_ST_SW_SESSION_TICKET_A) {
2635 		/* get session encoding length */
2636 		slen_full = i2d_SSL_SESSION(s->session, NULL);
2637 		/*
2638 		 * Some length values are 16 bits, so forget it if session is
2639  		 * too long
2640  		 */
2641 		if (slen_full > 0xFF00)
2642 			goto err;
2643 		senc = malloc(slen_full);
2644 		if (!senc)
2645 			goto err;
2646 		p = senc;
2647 		i2d_SSL_SESSION(s->session, &p);
2648 
2649 		/*
2650 		 * Create a fresh copy (not shared with other threads) to
2651 		 * clean up
2652 		 */
2653 		const_p = senc;
2654 		sess = d2i_SSL_SESSION(NULL, &const_p, slen_full);
2655 		if (sess == NULL)
2656 			goto err;
2657 
2658 		/* ID is irrelevant for the ticket */
2659 		sess->session_id_length = 0;
2660 
2661 		slen = i2d_SSL_SESSION(sess, NULL);
2662 		if (slen > slen_full) {
2663 			/* shouldn't ever happen */
2664 			goto err;
2665 		}
2666 		p = senc;
2667 		i2d_SSL_SESSION(sess, &p);
2668 		SSL_SESSION_free(sess);
2669 
2670 		/*
2671 		 * Grow buffer if need be: the length calculation is as
2672  		 * follows 1 (size of message name) + 3 (message length
2673  		 * bytes) + 4 (ticket lifetime hint) + 2 (ticket length) +
2674  		 * 16 (key name) + max_iv_len (iv length) +
2675  		 * session_length + max_enc_block_size (max encrypted session
2676  		 * length) + max_md_size (HMAC).
2677  		 */
2678 		if (!BUF_MEM_grow(s->internal->init_buf, ssl3_handshake_msg_hdr_len(s) +
2679 		    22 + EVP_MAX_IV_LENGTH + EVP_MAX_BLOCK_LENGTH +
2680 		    EVP_MAX_MD_SIZE + slen))
2681 			goto err;
2682 
2683 		d = p = ssl3_handshake_msg_start(s, SSL3_MT_NEWSESSION_TICKET);
2684 
2685 		EVP_CIPHER_CTX_init(&ctx);
2686 		HMAC_CTX_init(&hctx);
2687 
2688 		/*
2689 		 * Initialize HMAC and cipher contexts. If callback present
2690 		 * it does all the work otherwise use generated values
2691 		 * from parent ctx.
2692 		 */
2693 		if (tctx->internal->tlsext_ticket_key_cb) {
2694 			if (tctx->internal->tlsext_ticket_key_cb(s,
2695 			    key_name, iv, &ctx, &hctx, 1) < 0) {
2696 				EVP_CIPHER_CTX_cleanup(&ctx);
2697 				goto err;
2698 			}
2699 		} else {
2700 			arc4random_buf(iv, 16);
2701 			EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL,
2702 			    tctx->internal->tlsext_tick_aes_key, iv);
2703 			HMAC_Init_ex(&hctx, tctx->internal->tlsext_tick_hmac_key,
2704 			    16, tlsext_tick_md(), NULL);
2705 			memcpy(key_name, tctx->internal->tlsext_tick_key_name, 16);
2706 		}
2707 
2708 		/*
2709 		 * Ticket lifetime hint (advisory only):
2710 		 * We leave this unspecified for resumed session
2711 		 * (for simplicity), and guess that tickets for new
2712 		 * sessions will live as long as their sessions.
2713 		 */
2714 		l2n(s->internal->hit ? 0 : s->session->timeout, p);
2715 
2716 		/* Skip ticket length for now */
2717 		p += 2;
2718 		/* Output key name */
2719 		macstart = p;
2720 		memcpy(p, key_name, 16);
2721 		p += 16;
2722 		/* output IV */
2723 		memcpy(p, iv, EVP_CIPHER_CTX_iv_length(&ctx));
2724 		p += EVP_CIPHER_CTX_iv_length(&ctx);
2725 		/* Encrypt session data */
2726 		EVP_EncryptUpdate(&ctx, p, &len, senc, slen);
2727 		p += len;
2728 		EVP_EncryptFinal_ex(&ctx, p, &len);
2729 		p += len;
2730 		EVP_CIPHER_CTX_cleanup(&ctx);
2731 
2732 		HMAC_Update(&hctx, macstart, p - macstart);
2733 		HMAC_Final(&hctx, p, &hlen);
2734 		HMAC_CTX_cleanup(&hctx);
2735 		p += hlen;
2736 
2737 		/* Now write out lengths: p points to end of data written */
2738 		/* Total length */
2739 		len = p - d;
2740 
2741 		/* Skip ticket lifetime hint. */
2742 		p = d + 4;
2743 		s2n(len - 6, p); /* Message length */
2744 
2745 		ssl3_handshake_msg_finish(s, len);
2746 
2747 		S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_B;
2748 
2749 		freezero(senc, slen_full);
2750 	}
2751 
2752 	/* SSL3_ST_SW_SESSION_TICKET_B */
2753 	return (ssl3_handshake_write(s));
2754 
2755  err:
2756 	freezero(senc, slen_full);
2757 
2758 	return (-1);
2759 }
2760 
2761 int
2762 ssl3_send_cert_status(SSL *s)
2763 {
2764 	CBB cbb, certstatus, ocspresp;
2765 
2766 	memset(&cbb, 0, sizeof(cbb));
2767 
2768 	if (S3I(s)->hs.state == SSL3_ST_SW_CERT_STATUS_A) {
2769 		if (!ssl3_handshake_msg_start_cbb(s, &cbb, &certstatus,
2770 		    SSL3_MT_CERTIFICATE_STATUS))
2771 			goto err;
2772 		if (!CBB_add_u8(&certstatus, s->tlsext_status_type))
2773 			goto err;
2774 		if (!CBB_add_u24_length_prefixed(&certstatus, &ocspresp))
2775 			goto err;
2776 		if (!CBB_add_bytes(&ocspresp, s->internal->tlsext_ocsp_resp,
2777 		    s->internal->tlsext_ocsp_resplen))
2778 			goto err;
2779 		if (!ssl3_handshake_msg_finish_cbb(s, &cbb))
2780 			goto err;
2781 
2782 		S3I(s)->hs.state = SSL3_ST_SW_CERT_STATUS_B;
2783 	}
2784 
2785 	/* SSL3_ST_SW_CERT_STATUS_B */
2786 	return (ssl3_handshake_write(s));
2787 
2788  err:
2789 	CBB_cleanup(&cbb);
2790 
2791 	return (-1);
2792 }
2793