xref: /dragonfly/crypto/libressl/ssl/ssl_srvr.c (revision c9c5aa9e)
1 /* $OpenBSD: ssl_srvr.c,v 1.85 2020/09/24 18:12:00 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 				ssl3_release_init_buffer(s);
696 
697 			/* remove buffering on output */
698 			ssl_free_wbio_buffer(s);
699 
700 			s->internal->init_num = 0;
701 
702 			/* Skipped if we just sent a HelloRequest. */
703 			if (s->internal->renegotiate == 2) {
704 				s->internal->renegotiate = 0;
705 				s->internal->new_session = 0;
706 
707 				ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
708 
709 				s->ctx->internal->stats.sess_accept_good++;
710 				/* s->server=1; */
711 				s->internal->handshake_func = ssl3_accept;
712 
713 				if (cb != NULL)
714 					cb(s, SSL_CB_HANDSHAKE_DONE, 1);
715 			}
716 
717 			ret = 1;
718 
719 			if (SSL_IS_DTLS(s)) {
720 				/* Done handshaking, next message is client hello. */
721 				D1I(s)->handshake_read_seq = 0;
722 				/* Next message is server hello. */
723 				D1I(s)->handshake_write_seq = 0;
724 				D1I(s)->next_handshake_write_seq = 0;
725 			}
726 			goto end;
727 			/* break; */
728 
729 		default:
730 			SSLerror(s, SSL_R_UNKNOWN_STATE);
731 			ret = -1;
732 			goto end;
733 			/* break; */
734 		}
735 
736 		if (!S3I(s)->tmp.reuse_message && !skip) {
737 			if (s->internal->debug) {
738 				if ((ret = BIO_flush(s->wbio)) <= 0)
739 					goto end;
740 			}
741 
742 
743 			if ((cb != NULL) && (S3I(s)->hs.state != state)) {
744 				new_state = S3I(s)->hs.state;
745 				S3I(s)->hs.state = state;
746 				cb(s, SSL_CB_ACCEPT_LOOP, 1);
747 				S3I(s)->hs.state = new_state;
748 			}
749 		}
750 		skip = 0;
751 	}
752 end:
753 	/* BIO_flush(s->wbio); */
754 	s->internal->in_handshake--;
755 	if (cb != NULL)
756 		cb(s, SSL_CB_ACCEPT_EXIT, ret);
757 
758 	return (ret);
759 }
760 
761 int
762 ssl3_send_hello_request(SSL *s)
763 {
764 	CBB cbb, hello;
765 
766 	memset(&cbb, 0, sizeof(cbb));
767 
768 	if (S3I(s)->hs.state == SSL3_ST_SW_HELLO_REQ_A) {
769 		if (!ssl3_handshake_msg_start(s, &cbb, &hello,
770 		    SSL3_MT_HELLO_REQUEST))
771 			goto err;
772 		if (!ssl3_handshake_msg_finish(s, &cbb))
773 			goto err;
774 
775 		S3I(s)->hs.state = SSL3_ST_SW_HELLO_REQ_B;
776 	}
777 
778 	/* SSL3_ST_SW_HELLO_REQ_B */
779 	return (ssl3_handshake_write(s));
780 
781  err:
782 	CBB_cleanup(&cbb);
783 
784 	return (-1);
785 }
786 
787 int
788 ssl3_get_client_hello(SSL *s)
789 {
790 	CBS cbs, client_random, session_id, cookie, cipher_suites;
791 	CBS compression_methods;
792 	uint16_t client_version;
793 	uint8_t comp_method;
794 	int comp_null;
795 	int i, j, ok, al, ret = -1, cookie_valid = 0;
796 	long n;
797 	unsigned long id;
798 	SSL_CIPHER *c;
799 	STACK_OF(SSL_CIPHER) *ciphers = NULL;
800 	unsigned long alg_k;
801 	const SSL_METHOD *method;
802 	uint16_t max_version, shared_version;
803 
804 	/*
805 	 * We do this so that we will respond with our native type.
806 	 * If we are TLSv1 and we get SSLv3, we will respond with TLSv1,
807 	 * This down switching should be handled by a different method.
808 	 * If we are SSLv3, we will respond with SSLv3, even if prompted with
809 	 * TLSv1.
810 	 */
811 	if (S3I(s)->hs.state == SSL3_ST_SR_CLNT_HELLO_A) {
812 		S3I(s)->hs.state = SSL3_ST_SR_CLNT_HELLO_B;
813 	}
814 
815 	s->internal->first_packet = 1;
816 	n = ssl3_get_message(s, SSL3_ST_SR_CLNT_HELLO_B,
817 	    SSL3_ST_SR_CLNT_HELLO_C, SSL3_MT_CLIENT_HELLO,
818 	    SSL3_RT_MAX_PLAIN_LENGTH, &ok);
819 	if (!ok)
820 		return ((int)n);
821 	s->internal->first_packet = 0;
822 
823 	if (n < 0)
824 		goto err;
825 
826 	CBS_init(&cbs, s->internal->init_msg, n);
827 
828 	/* Parse client hello up until the extensions (if any). */
829 	if (!CBS_get_u16(&cbs, &client_version))
830 		goto truncated;
831 	if (!CBS_get_bytes(&cbs, &client_random, SSL3_RANDOM_SIZE))
832 		goto truncated;
833 	if (!CBS_get_u8_length_prefixed(&cbs, &session_id))
834 		goto truncated;
835 	if (CBS_len(&session_id) > SSL3_SESSION_ID_SIZE) {
836 		al = SSL_AD_ILLEGAL_PARAMETER;
837 		SSLerror(s, SSL_R_SSL3_SESSION_ID_TOO_LONG);
838 		goto f_err;
839 	}
840 	if (SSL_IS_DTLS(s)) {
841 		if (!CBS_get_u8_length_prefixed(&cbs, &cookie))
842 			goto truncated;
843 	}
844 	if (!CBS_get_u16_length_prefixed(&cbs, &cipher_suites))
845 		goto truncated;
846 	if (!CBS_get_u8_length_prefixed(&cbs, &compression_methods))
847 		goto truncated;
848 
849 	/*
850 	 * Use version from inside client hello, not from record header.
851 	 * (may differ: see RFC 2246, Appendix E, second paragraph)
852 	 */
853 	if (!ssl_downgrade_max_version(s, &max_version))
854 		goto err;
855 	if (ssl_max_shared_version(s, client_version, &shared_version) != 1) {
856 		SSLerror(s, SSL_R_WRONG_VERSION_NUMBER);
857 		if ((s->client_version >> 8) == SSL3_VERSION_MAJOR &&
858 		    !s->internal->enc_write_ctx && !s->internal->write_hash) {
859 			/*
860 			 * Similar to ssl3_get_record, send alert using remote
861 			 * version number.
862 			 */
863 			s->version = s->client_version;
864 		}
865 		al = SSL_AD_PROTOCOL_VERSION;
866 		goto f_err;
867 	}
868 	s->client_version = client_version;
869 	s->version = shared_version;
870 
871 	if ((method = ssl_get_server_method(shared_version)) == NULL) {
872 		SSLerror(s, ERR_R_INTERNAL_ERROR);
873 		goto err;
874 	}
875 	s->method = method;
876 
877 	/*
878 	 * If we require cookies (DTLS) and this ClientHello does not contain
879 	 * one, just return since we do not want to allocate any memory yet.
880 	 * So check cookie length...
881 	 */
882 	if (SSL_IS_DTLS(s)) {
883 		if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
884 			if (CBS_len(&cookie) == 0)
885 				return (1);
886 		}
887 	}
888 
889 	if (!CBS_write_bytes(&client_random, s->s3->client_random,
890 	    sizeof(s->s3->client_random), NULL))
891 		goto err;
892 
893 	s->internal->hit = 0;
894 
895 	/*
896 	 * Versions before 0.9.7 always allow clients to resume sessions in
897 	 * renegotiation. 0.9.7 and later allow this by default, but optionally
898 	 * ignore resumption requests with flag
899 	 * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag
900 	 * rather than a change to default behavior so that applications
901 	 * relying on this for security won't even compile against older
902 	 * library versions).
903 	 *
904 	 * 1.0.1 and later also have a function SSL_renegotiate_abbreviated()
905 	 * to request renegotiation but not a new session (s->internal->new_session
906 	 * remains unset): for servers, this essentially just means that the
907 	 * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
908 	 * ignored.
909 	 */
910 	if ((s->internal->new_session && (s->internal->options &
911 	    SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
912 		if (!ssl_get_new_session(s, 1))
913 			goto err;
914 	} else {
915 		CBS ext_block;
916 
917 		CBS_dup(&cbs, &ext_block);
918 
919 		i = ssl_get_prev_session(s, &session_id, &ext_block, &al);
920 		if (i == 1) { /* previous session */
921 			s->internal->hit = 1;
922 		} else if (i == -1)
923 			goto f_err;
924 		else {
925 			/* i == 0 */
926 			if (!ssl_get_new_session(s, 1))
927 				goto err;
928 		}
929 	}
930 
931 	if (SSL_IS_DTLS(s)) {
932 		/*
933 		 * The ClientHello may contain a cookie even if the HelloVerify
934 		 * message has not been sent - make sure that it does not cause
935 		 * an overflow.
936 		 */
937 		if (CBS_len(&cookie) > sizeof(D1I(s)->rcvd_cookie)) {
938 			al = SSL_AD_DECODE_ERROR;
939 			SSLerror(s, SSL_R_COOKIE_MISMATCH);
940 			goto f_err;
941 		}
942 
943 		/* Verify the cookie if appropriate option is set. */
944 		if ((SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) &&
945 		    CBS_len(&cookie) > 0) {
946 			size_t cookie_len;
947 
948 			/* XXX - rcvd_cookie seems to only be used here... */
949 			if (!CBS_write_bytes(&cookie, D1I(s)->rcvd_cookie,
950 			    sizeof(D1I(s)->rcvd_cookie), &cookie_len))
951 				goto err;
952 
953 			if (s->ctx->internal->app_verify_cookie_cb != NULL) {
954 				if (s->ctx->internal->app_verify_cookie_cb(s,
955 				    D1I(s)->rcvd_cookie, cookie_len) == 0) {
956 					al = SSL_AD_HANDSHAKE_FAILURE;
957 					SSLerror(s, SSL_R_COOKIE_MISMATCH);
958 					goto f_err;
959 				}
960 				/* else cookie verification succeeded */
961 			/* XXX - can d1->cookie_len > sizeof(rcvd_cookie) ? */
962 			} else if (timingsafe_memcmp(D1I(s)->rcvd_cookie,
963 			    D1I(s)->cookie, D1I(s)->cookie_len) != 0) {
964 				/* default verification */
965 				al = SSL_AD_HANDSHAKE_FAILURE;
966 				SSLerror(s, SSL_R_COOKIE_MISMATCH);
967 				goto f_err;
968 			}
969 			cookie_valid = 1;
970 		}
971 	}
972 
973 	/* XXX - This logic seems wrong... */
974 	if (CBS_len(&cipher_suites) == 0 && CBS_len(&session_id) != 0) {
975 		/* we need a cipher if we are not resuming a session */
976 		al = SSL_AD_ILLEGAL_PARAMETER;
977 		SSLerror(s, SSL_R_NO_CIPHERS_SPECIFIED);
978 		goto f_err;
979 	}
980 
981 	if (CBS_len(&cipher_suites) > 0) {
982 		if ((ciphers = ssl_bytes_to_cipher_list(s,
983 		    &cipher_suites)) == NULL)
984 			goto err;
985 	}
986 
987 	/* If it is a hit, check that the cipher is in the list */
988 	/* XXX - CBS_len(&cipher_suites) will always be zero here... */
989 	if (s->internal->hit && CBS_len(&cipher_suites) > 0) {
990 		j = 0;
991 		id = s->session->cipher->id;
992 
993 		for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
994 			c = sk_SSL_CIPHER_value(ciphers, i);
995 			if (c->id == id) {
996 				j = 1;
997 				break;
998 			}
999 		}
1000 		if (j == 0) {
1001 			/*
1002 			 * We need to have the cipher in the cipher
1003 			 * list if we are asked to reuse it
1004 			 */
1005 			al = SSL_AD_ILLEGAL_PARAMETER;
1006 			SSLerror(s, SSL_R_REQUIRED_CIPHER_MISSING);
1007 			goto f_err;
1008 		}
1009 	}
1010 
1011 	comp_null = 0;
1012 	while (CBS_len(&compression_methods) > 0) {
1013 		if (!CBS_get_u8(&compression_methods, &comp_method))
1014 			goto truncated;
1015 		if (comp_method == 0)
1016 			comp_null = 1;
1017 	}
1018 	if (comp_null == 0) {
1019 		al = SSL_AD_DECODE_ERROR;
1020 		SSLerror(s, SSL_R_NO_COMPRESSION_SPECIFIED);
1021 		goto f_err;
1022 	}
1023 
1024 	if (!tlsext_server_parse(s, SSL_TLSEXT_MSG_CH, &cbs, &al)) {
1025 		SSLerror(s, SSL_R_PARSE_TLSEXT);
1026 		goto f_err;
1027 	}
1028 
1029 	if (!S3I(s)->renegotiate_seen && s->internal->renegotiate) {
1030 		al = SSL_AD_HANDSHAKE_FAILURE;
1031 		SSLerror(s, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
1032 		goto f_err;
1033 	}
1034 
1035 	if (ssl_check_clienthello_tlsext_early(s) <= 0) {
1036 		SSLerror(s, SSL_R_CLIENTHELLO_TLSEXT);
1037 		goto err;
1038 	}
1039 
1040 	/*
1041 	 * Check if we want to use external pre-shared secret for this
1042 	 * handshake for not reused session only. We need to generate
1043 	 * server_random before calling tls_session_secret_cb in order to allow
1044 	 * SessionTicket processing to use it in key derivation.
1045 	 */
1046 	arc4random_buf(s->s3->server_random, SSL3_RANDOM_SIZE);
1047 
1048 	if (!SSL_IS_DTLS(s) && max_version >= TLS1_2_VERSION &&
1049 	    s->version < max_version) {
1050 		/*
1051 		 * RFC 8446 section 4.1.3. If we are downgrading from TLS 1.3
1052 		 * we must set the last 8 bytes of the server random to magical
1053 		 * values to indicate we meant to downgrade.  For TLS 1.2 it is
1054 		 * recommended that we do the same.
1055 		 */
1056 		size_t index = SSL3_RANDOM_SIZE - sizeof(tls13_downgrade_12);
1057 		uint8_t *magic = &s->s3->server_random[index];
1058 		if (s->version == TLS1_2_VERSION) {
1059 			/* Indicate we chose to downgrade to 1.2. */
1060 			memcpy(magic, tls13_downgrade_12,
1061 			    sizeof(tls13_downgrade_12));
1062 		} else {
1063 			/* Indicate we chose to downgrade to 1.1 or lower */
1064 			memcpy(magic, tls13_downgrade_11,
1065 			    sizeof(tls13_downgrade_11));
1066 		}
1067 	}
1068 
1069 	if (!s->internal->hit && s->internal->tls_session_secret_cb) {
1070 		SSL_CIPHER *pref_cipher = NULL;
1071 
1072 		s->session->master_key_length = sizeof(s->session->master_key);
1073 		if (s->internal->tls_session_secret_cb(s, s->session->master_key,
1074 		    &s->session->master_key_length, ciphers, &pref_cipher,
1075 		    s->internal->tls_session_secret_cb_arg)) {
1076 			s->internal->hit = 1;
1077 			s->session->ciphers = ciphers;
1078 			s->session->verify_result = X509_V_OK;
1079 
1080 			ciphers = NULL;
1081 
1082 			/* check if some cipher was preferred by call back */
1083 			pref_cipher = pref_cipher ? pref_cipher :
1084 			    ssl3_choose_cipher(s, s->session->ciphers,
1085 			    SSL_get_ciphers(s));
1086 			if (pref_cipher == NULL) {
1087 				al = SSL_AD_HANDSHAKE_FAILURE;
1088 				SSLerror(s, SSL_R_NO_SHARED_CIPHER);
1089 				goto f_err;
1090 			}
1091 
1092 			s->session->cipher = pref_cipher;
1093 
1094 			sk_SSL_CIPHER_free(s->cipher_list);
1095 			s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
1096 		}
1097 	}
1098 
1099 	/*
1100 	 * Given s->session->ciphers and SSL_get_ciphers, we must
1101 	 * pick a cipher
1102 	 */
1103 
1104 	if (!s->internal->hit) {
1105 		sk_SSL_CIPHER_free(s->session->ciphers);
1106 		s->session->ciphers = ciphers;
1107 		if (ciphers == NULL) {
1108 			al = SSL_AD_ILLEGAL_PARAMETER;
1109 			SSLerror(s, SSL_R_NO_CIPHERS_PASSED);
1110 			goto f_err;
1111 		}
1112 		ciphers = NULL;
1113 		c = ssl3_choose_cipher(s, s->session->ciphers,
1114 		SSL_get_ciphers(s));
1115 
1116 		if (c == NULL) {
1117 			al = SSL_AD_HANDSHAKE_FAILURE;
1118 			SSLerror(s, SSL_R_NO_SHARED_CIPHER);
1119 			goto f_err;
1120 		}
1121 		S3I(s)->hs.new_cipher = c;
1122 	} else {
1123 		S3I(s)->hs.new_cipher = s->session->cipher;
1124 	}
1125 
1126 	if (!tls1_transcript_hash_init(s))
1127 		goto err;
1128 
1129 	alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
1130 	if (!(SSL_USE_SIGALGS(s) || (alg_k & SSL_kGOST)) ||
1131 	    !(s->verify_mode & SSL_VERIFY_PEER))
1132 		tls1_transcript_free(s);
1133 
1134 	/*
1135 	 * We now have the following setup.
1136 	 * client_random
1137 	 * cipher_list 		- our prefered list of ciphers
1138 	 * ciphers 		- the clients prefered list of ciphers
1139 	 * compression		- basically ignored right now
1140 	 * ssl version is set	- sslv3
1141 	 * s->session		- The ssl session has been setup.
1142 	 * s->internal->hit		- session reuse flag
1143 	 * s->hs.new_cipher	- the new cipher to use.
1144 	 */
1145 
1146 	/* Handles TLS extensions that we couldn't check earlier */
1147 	if (ssl_check_clienthello_tlsext_late(s) <= 0) {
1148 		SSLerror(s, SSL_R_CLIENTHELLO_TLSEXT);
1149 		goto err;
1150 	}
1151 
1152 	ret = cookie_valid ? 2 : 1;
1153 
1154 	if (0) {
1155 truncated:
1156 		al = SSL_AD_DECODE_ERROR;
1157 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1158 f_err:
1159 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
1160 	}
1161 err:
1162 	sk_SSL_CIPHER_free(ciphers);
1163 
1164 	return (ret);
1165 }
1166 
1167 int
1168 ssl3_send_server_hello(SSL *s)
1169 {
1170 	CBB cbb, server_hello, session_id;
1171 	size_t sl;
1172 
1173 	memset(&cbb, 0, sizeof(cbb));
1174 
1175 	if (S3I(s)->hs.state == SSL3_ST_SW_SRVR_HELLO_A) {
1176 		if (!ssl3_handshake_msg_start(s, &cbb, &server_hello,
1177 		    SSL3_MT_SERVER_HELLO))
1178 			goto err;
1179 
1180 		if (!CBB_add_u16(&server_hello, s->version))
1181 			goto err;
1182 		if (!CBB_add_bytes(&server_hello, s->s3->server_random,
1183 		    sizeof(s->s3->server_random)))
1184 			goto err;
1185 
1186 		/*
1187 		 * There are several cases for the session ID to send
1188 		 * back in the server hello:
1189 		 *
1190 		 * - For session reuse from the session cache,
1191 		 *   we send back the old session ID.
1192 		 * - If stateless session reuse (using a session ticket)
1193 		 *   is successful, we send back the client's "session ID"
1194 		 *   (which doesn't actually identify the session).
1195 		 * - If it is a new session, we send back the new
1196 		 *   session ID.
1197 		 * - However, if we want the new session to be single-use,
1198 		 *   we send back a 0-length session ID.
1199 		 *
1200 		 * s->internal->hit is non-zero in either case of session reuse,
1201 		 * so the following won't overwrite an ID that we're supposed
1202 		 * to send back.
1203 		 */
1204 		if (!(s->ctx->internal->session_cache_mode & SSL_SESS_CACHE_SERVER)
1205 		    && !s->internal->hit)
1206 			s->session->session_id_length = 0;
1207 
1208 		sl = s->session->session_id_length;
1209 		if (sl > sizeof(s->session->session_id)) {
1210 			SSLerror(s, ERR_R_INTERNAL_ERROR);
1211 			goto err;
1212 		}
1213 		if (!CBB_add_u8_length_prefixed(&server_hello, &session_id))
1214 			goto err;
1215 		if (!CBB_add_bytes(&session_id, s->session->session_id, sl))
1216 			goto err;
1217 
1218 		/* Cipher suite. */
1219 		if (!CBB_add_u16(&server_hello,
1220 		    ssl3_cipher_get_value(S3I(s)->hs.new_cipher)))
1221 			goto err;
1222 
1223 		/* Compression method (null). */
1224 		if (!CBB_add_u8(&server_hello, 0))
1225 			goto err;
1226 
1227 		/* TLS extensions */
1228 		if (!tlsext_server_build(s, SSL_TLSEXT_MSG_SH, &server_hello)) {
1229 			SSLerror(s, ERR_R_INTERNAL_ERROR);
1230 			goto err;
1231 		}
1232 
1233 		if (!ssl3_handshake_msg_finish(s, &cbb))
1234 			goto err;
1235 	}
1236 
1237 	/* SSL3_ST_SW_SRVR_HELLO_B */
1238 	return (ssl3_handshake_write(s));
1239 
1240  err:
1241 	CBB_cleanup(&cbb);
1242 
1243 	return (-1);
1244 }
1245 
1246 int
1247 ssl3_send_server_done(SSL *s)
1248 {
1249 	CBB cbb, done;
1250 
1251 	memset(&cbb, 0, sizeof(cbb));
1252 
1253 	if (S3I(s)->hs.state == SSL3_ST_SW_SRVR_DONE_A) {
1254 		if (!ssl3_handshake_msg_start(s, &cbb, &done,
1255 		    SSL3_MT_SERVER_DONE))
1256 			goto err;
1257 		if (!ssl3_handshake_msg_finish(s, &cbb))
1258 			goto err;
1259 
1260 		S3I(s)->hs.state = SSL3_ST_SW_SRVR_DONE_B;
1261 	}
1262 
1263 	/* SSL3_ST_SW_SRVR_DONE_B */
1264 	return (ssl3_handshake_write(s));
1265 
1266  err:
1267 	CBB_cleanup(&cbb);
1268 
1269 	return (-1);
1270 }
1271 
1272 static int
1273 ssl3_send_server_kex_dhe(SSL *s, CBB *cbb)
1274 {
1275 	CBB dh_p, dh_g, dh_Ys;
1276 	DH *dh = NULL, *dhp;
1277 	unsigned char *data;
1278 	int al;
1279 
1280 	if (s->cert->dh_tmp_auto != 0) {
1281 		if ((dhp = ssl_get_auto_dh(s)) == NULL) {
1282 			al = SSL_AD_INTERNAL_ERROR;
1283 			SSLerror(s, ERR_R_INTERNAL_ERROR);
1284 			goto f_err;
1285 		}
1286 	} else
1287 		dhp = s->cert->dh_tmp;
1288 
1289 	if (dhp == NULL && s->cert->dh_tmp_cb != NULL)
1290 		dhp = s->cert->dh_tmp_cb(s, 0,
1291 		    SSL_C_PKEYLENGTH(S3I(s)->hs.new_cipher));
1292 
1293 	if (dhp == NULL) {
1294 		al = SSL_AD_HANDSHAKE_FAILURE;
1295 		SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
1296 		goto f_err;
1297 	}
1298 
1299 	if (S3I(s)->tmp.dh != NULL) {
1300 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1301 		goto err;
1302 	}
1303 
1304 	if (s->cert->dh_tmp_auto != 0) {
1305 		dh = dhp;
1306 	} else if ((dh = DHparams_dup(dhp)) == NULL) {
1307 		SSLerror(s, ERR_R_DH_LIB);
1308 		goto err;
1309 	}
1310 	S3I(s)->tmp.dh = dh;
1311 	if (!DH_generate_key(dh)) {
1312 		SSLerror(s, ERR_R_DH_LIB);
1313 		goto err;
1314 	}
1315 
1316 	/*
1317 	 * Serialize the DH parameters and public key.
1318 	 */
1319 	if (!CBB_add_u16_length_prefixed(cbb, &dh_p))
1320 		goto err;
1321 	if (!CBB_add_space(&dh_p, &data, BN_num_bytes(dh->p)))
1322 		goto err;
1323 	BN_bn2bin(dh->p, data);
1324 
1325 	if (!CBB_add_u16_length_prefixed(cbb, &dh_g))
1326 		goto err;
1327 	if (!CBB_add_space(&dh_g, &data, BN_num_bytes(dh->g)))
1328 		goto err;
1329 	BN_bn2bin(dh->g, data);
1330 
1331 	if (!CBB_add_u16_length_prefixed(cbb, &dh_Ys))
1332 		goto err;
1333 	if (!CBB_add_space(&dh_Ys, &data, BN_num_bytes(dh->pub_key)))
1334 		goto err;
1335 	BN_bn2bin(dh->pub_key, data);
1336 
1337 	if (!CBB_flush(cbb))
1338 		goto err;
1339 
1340 	return (1);
1341 
1342  f_err:
1343 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1344  err:
1345 	return (-1);
1346 }
1347 
1348 static int
1349 ssl3_send_server_kex_ecdhe_ecp(SSL *s, int nid, CBB *cbb)
1350 {
1351 	uint16_t curve_id;
1352 	EC_KEY *ecdh;
1353 	CBB ecpoint;
1354 	int al;
1355 
1356 	/*
1357 	 * Only named curves are supported in ECDH ephemeral key exchanges.
1358 	 * For supported named curves, curve_id is non-zero.
1359 	 */
1360 	if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
1361 		SSLerror(s, SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
1362 		goto err;
1363 	}
1364 
1365 	if (S3I(s)->tmp.ecdh != NULL) {
1366 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1367 		goto err;
1368 	}
1369 
1370 	if ((S3I(s)->tmp.ecdh = EC_KEY_new()) == NULL) {
1371 		al = SSL_AD_HANDSHAKE_FAILURE;
1372 		SSLerror(s, SSL_R_MISSING_TMP_ECDH_KEY);
1373 		goto f_err;
1374 	}
1375 	S3I(s)->tmp.ecdh_nid = nid;
1376 	ecdh = S3I(s)->tmp.ecdh;
1377 
1378 	if (!ssl_kex_generate_ecdhe_ecp(ecdh, nid))
1379 		goto err;
1380 
1381 	/*
1382 	 * Encode the public key.
1383 	 *
1384 	 * Only named curves are supported in ECDH ephemeral key exchanges.
1385 	 * In this case the ServerKeyExchange message has:
1386 	 * [1 byte CurveType], [2 byte CurveName]
1387 	 * [1 byte length of encoded point], followed by
1388 	 * the actual encoded point itself.
1389 	 */
1390 	if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
1391 		goto err;
1392 	if (!CBB_add_u16(cbb, curve_id))
1393 		goto err;
1394 	if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
1395 		goto err;
1396 	if (!ssl_kex_public_ecdhe_ecp(ecdh, &ecpoint))
1397 		goto err;
1398 	if (!CBB_flush(cbb))
1399 		goto err;
1400 
1401 	return (1);
1402 
1403  f_err:
1404 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1405  err:
1406 	return (-1);
1407 }
1408 
1409 static int
1410 ssl3_send_server_kex_ecdhe_ecx(SSL *s, int nid, CBB *cbb)
1411 {
1412 	uint8_t *public_key = NULL, *private_key = NULL;
1413 	uint16_t curve_id;
1414 	CBB ecpoint;
1415 	int ret = -1;
1416 
1417 	/* Generate an X25519 key pair. */
1418 	if (S3I(s)->tmp.x25519 != NULL) {
1419 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1420 		goto err;
1421 	}
1422 	if ((private_key = malloc(X25519_KEY_LENGTH)) == NULL)
1423 		goto err;
1424 	if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL)
1425 		goto err;
1426 	X25519_keypair(public_key, private_key);
1427 
1428 	/* Serialize public key. */
1429 	if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
1430 		SSLerror(s, SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
1431 		goto err;
1432 	}
1433 
1434 	if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
1435 		goto err;
1436 	if (!CBB_add_u16(cbb, curve_id))
1437 		goto err;
1438 	if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
1439 		goto err;
1440 	if (!CBB_add_bytes(&ecpoint, public_key, X25519_KEY_LENGTH))
1441 		goto err;
1442 	if (!CBB_flush(cbb))
1443 		goto err;
1444 
1445 	S3I(s)->tmp.x25519 = private_key;
1446 	private_key = NULL;
1447 	ret = 1;
1448 
1449  err:
1450 	free(public_key);
1451 	freezero(private_key, X25519_KEY_LENGTH);
1452 
1453 	return (ret);
1454 }
1455 
1456 static int
1457 ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
1458 {
1459 	int nid;
1460 
1461 	nid = tls1_get_shared_curve(s);
1462 
1463 	if (nid == NID_X25519)
1464 		return ssl3_send_server_kex_ecdhe_ecx(s, nid, cbb);
1465 
1466 	return ssl3_send_server_kex_ecdhe_ecp(s, nid, cbb);
1467 }
1468 
1469 int
1470 ssl3_send_server_key_exchange(SSL *s)
1471 {
1472 	CBB cbb, cbb_params, cbb_signature, server_kex;
1473 	const struct ssl_sigalg *sigalg = NULL;
1474 	unsigned char *signature = NULL;
1475 	size_t signature_len = 0;
1476 	unsigned char *params = NULL;
1477 	size_t params_len;
1478 	const EVP_MD *md = NULL;
1479 	unsigned long type;
1480 	EVP_MD_CTX md_ctx;
1481 	EVP_PKEY_CTX *pctx;
1482 	EVP_PKEY *pkey;
1483 	int al;
1484 
1485 	memset(&cbb, 0, sizeof(cbb));
1486 	memset(&cbb_params, 0, sizeof(cbb_params));
1487 
1488 	EVP_MD_CTX_init(&md_ctx);
1489 
1490 	if (S3I(s)->hs.state == SSL3_ST_SW_KEY_EXCH_A) {
1491 
1492 		if (!ssl3_handshake_msg_start(s, &cbb, &server_kex,
1493 		    SSL3_MT_SERVER_KEY_EXCHANGE))
1494 			goto err;
1495 
1496 		if (!CBB_init(&cbb_params, 0))
1497 			goto err;
1498 
1499 		type = S3I(s)->hs.new_cipher->algorithm_mkey;
1500 		if (type & SSL_kDHE) {
1501 			if (ssl3_send_server_kex_dhe(s, &cbb_params) != 1)
1502 				goto err;
1503 		} else if (type & SSL_kECDHE) {
1504 			if (ssl3_send_server_kex_ecdhe(s, &cbb_params) != 1)
1505 				goto err;
1506 		} else {
1507 			al = SSL_AD_HANDSHAKE_FAILURE;
1508 			SSLerror(s, SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
1509 			goto f_err;
1510 		}
1511 
1512 		if (!CBB_finish(&cbb_params, &params, &params_len))
1513 			goto err;
1514 
1515 		if (!CBB_add_bytes(&server_kex, params, params_len))
1516 			goto err;
1517 
1518 		/* Add signature unless anonymous. */
1519 		if (!(S3I(s)->hs.new_cipher->algorithm_auth & SSL_aNULL)) {
1520 			if ((pkey = ssl_get_sign_pkey(s, S3I(s)->hs.new_cipher,
1521 			    &md, &sigalg)) == NULL) {
1522 				al = SSL_AD_DECODE_ERROR;
1523 				goto f_err;
1524 			}
1525 
1526 			/* Send signature algorithm. */
1527 			if (SSL_USE_SIGALGS(s)) {
1528 				if (!CBB_add_u16(&server_kex, sigalg->value)) {
1529 					al = SSL_AD_INTERNAL_ERROR;
1530 					SSLerror(s, ERR_R_INTERNAL_ERROR);
1531 					goto f_err;
1532 				}
1533 			}
1534 
1535 			if (!EVP_DigestSignInit(&md_ctx, &pctx, md, NULL, pkey)) {
1536 				SSLerror(s, ERR_R_EVP_LIB);
1537 				goto err;
1538 			}
1539 			if ((sigalg->flags & SIGALG_FLAG_RSA_PSS) &&
1540 			    (!EVP_PKEY_CTX_set_rsa_padding(pctx,
1541 			    RSA_PKCS1_PSS_PADDING) ||
1542 			    !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1))) {
1543 				SSLerror(s, ERR_R_EVP_LIB);
1544 				goto err;
1545 			}
1546 			if (!EVP_DigestSignUpdate(&md_ctx, s->s3->client_random,
1547 			    SSL3_RANDOM_SIZE)) {
1548 				SSLerror(s, ERR_R_EVP_LIB);
1549 				goto err;
1550 			}
1551 			if (!EVP_DigestSignUpdate(&md_ctx, s->s3->server_random,
1552 			    SSL3_RANDOM_SIZE)) {
1553 				SSLerror(s, ERR_R_EVP_LIB);
1554 				goto err;
1555 			}
1556 			if (!EVP_DigestSignUpdate(&md_ctx, params, params_len)) {
1557 				SSLerror(s, ERR_R_EVP_LIB);
1558 				goto err;
1559 			}
1560 			if (!EVP_DigestSignFinal(&md_ctx, NULL, &signature_len) ||
1561 			    !signature_len) {
1562 				SSLerror(s, ERR_R_EVP_LIB);
1563 				goto err;
1564 			}
1565 			if ((signature = calloc(1, signature_len)) == NULL) {
1566 				SSLerror(s, ERR_R_MALLOC_FAILURE);
1567 				goto err;
1568 			}
1569 			if (!EVP_DigestSignFinal(&md_ctx, signature, &signature_len)) {
1570 				SSLerror(s, ERR_R_EVP_LIB);
1571 				goto err;
1572 			}
1573 
1574 			if (!CBB_add_u16_length_prefixed(&server_kex,
1575 			    &cbb_signature))
1576 				goto err;
1577 			if (!CBB_add_bytes(&cbb_signature, signature,
1578 			    signature_len))
1579 				goto err;
1580 		}
1581 
1582 		if (!ssl3_handshake_msg_finish(s, &cbb))
1583 			goto err;
1584 
1585 		S3I(s)->hs.state = SSL3_ST_SW_KEY_EXCH_B;
1586 	}
1587 
1588 	EVP_MD_CTX_cleanup(&md_ctx);
1589 	free(params);
1590 	free(signature);
1591 
1592 	return (ssl3_handshake_write(s));
1593 
1594  f_err:
1595 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1596  err:
1597 	CBB_cleanup(&cbb_params);
1598 	CBB_cleanup(&cbb);
1599 	EVP_MD_CTX_cleanup(&md_ctx);
1600 	free(params);
1601 	free(signature);
1602 
1603 	return (-1);
1604 }
1605 
1606 int
1607 ssl3_send_certificate_request(SSL *s)
1608 {
1609 	CBB cbb, cert_request, cert_types, sigalgs, cert_auth, dn;
1610 	STACK_OF(X509_NAME) *sk = NULL;
1611 	X509_NAME *name;
1612 	int i;
1613 
1614 	/*
1615 	 * Certificate Request - RFC 5246 section 7.4.4.
1616 	 */
1617 
1618 	memset(&cbb, 0, sizeof(cbb));
1619 
1620 	if (S3I(s)->hs.state == SSL3_ST_SW_CERT_REQ_A) {
1621 		if (!ssl3_handshake_msg_start(s, &cbb, &cert_request,
1622 		    SSL3_MT_CERTIFICATE_REQUEST))
1623 			goto err;
1624 
1625 		if (!CBB_add_u8_length_prefixed(&cert_request, &cert_types))
1626 			goto err;
1627 		if (!ssl3_get_req_cert_types(s, &cert_types))
1628 			goto err;
1629 
1630 		if (SSL_USE_SIGALGS(s)) {
1631 			if (!CBB_add_u16_length_prefixed(&cert_request, &sigalgs))
1632 				goto err;
1633 			if (!ssl_sigalgs_build(&sigalgs, tls12_sigalgs, tls12_sigalgs_len))
1634 				goto err;
1635 		}
1636 
1637 		if (!CBB_add_u16_length_prefixed(&cert_request, &cert_auth))
1638 			goto err;
1639 
1640 		sk = SSL_get_client_CA_list(s);
1641 		for (i = 0; i < sk_X509_NAME_num(sk); i++) {
1642 			unsigned char *name_data;
1643 			size_t name_len;
1644 
1645 			name = sk_X509_NAME_value(sk, i);
1646 			name_len = i2d_X509_NAME(name, NULL);
1647 
1648 			if (!CBB_add_u16_length_prefixed(&cert_auth, &dn))
1649 				goto err;
1650 			if (!CBB_add_space(&dn, &name_data, name_len))
1651 				goto err;
1652 			if (i2d_X509_NAME(name, &name_data) != name_len)
1653 				goto err;
1654 		}
1655 
1656 		if (!ssl3_handshake_msg_finish(s, &cbb))
1657 			goto err;
1658 
1659 		S3I(s)->hs.state = SSL3_ST_SW_CERT_REQ_B;
1660 	}
1661 
1662 	/* SSL3_ST_SW_CERT_REQ_B */
1663 	return (ssl3_handshake_write(s));
1664 
1665  err:
1666 	CBB_cleanup(&cbb);
1667 
1668 	return (-1);
1669 }
1670 
1671 static int
1672 ssl3_get_client_kex_rsa(SSL *s, CBS *cbs)
1673 {
1674 	unsigned char fakekey[SSL_MAX_MASTER_KEY_LENGTH];
1675 	unsigned char *pms = NULL;
1676 	unsigned char *p;
1677 	size_t pms_len = 0;
1678 	EVP_PKEY *pkey = NULL;
1679 	RSA *rsa = NULL;
1680 	CBS enc_pms;
1681 	int decrypt_len;
1682 	int al = -1;
1683 
1684 	arc4random_buf(fakekey, sizeof(fakekey));
1685 	fakekey[0] = s->client_version >> 8;
1686 	fakekey[1] = s->client_version & 0xff;
1687 
1688 	pkey = s->cert->pkeys[SSL_PKEY_RSA].privatekey;
1689 	if ((pkey == NULL) || (pkey->type != EVP_PKEY_RSA) ||
1690 	    (pkey->pkey.rsa == NULL)) {
1691 		al = SSL_AD_HANDSHAKE_FAILURE;
1692 		SSLerror(s, SSL_R_MISSING_RSA_CERTIFICATE);
1693 		goto f_err;
1694 	}
1695 	rsa = pkey->pkey.rsa;
1696 
1697 	pms_len = RSA_size(rsa);
1698 	if (pms_len < SSL_MAX_MASTER_KEY_LENGTH)
1699 		goto err;
1700 	if ((pms = malloc(pms_len)) == NULL)
1701 		goto err;
1702 	p = pms;
1703 
1704 	if (!CBS_get_u16_length_prefixed(cbs, &enc_pms))
1705 		goto truncated;
1706 	if (CBS_len(cbs) != 0 || CBS_len(&enc_pms) != RSA_size(rsa)) {
1707 		SSLerror(s, SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG);
1708 		goto err;
1709 	}
1710 
1711 	decrypt_len = RSA_private_decrypt(CBS_len(&enc_pms), CBS_data(&enc_pms),
1712 	    pms, rsa, RSA_PKCS1_PADDING);
1713 
1714 	ERR_clear_error();
1715 
1716 	if (decrypt_len != SSL_MAX_MASTER_KEY_LENGTH) {
1717 		al = SSL_AD_DECODE_ERROR;
1718 		/* SSLerror(s, SSL_R_BAD_RSA_DECRYPT); */
1719 	}
1720 
1721 	if ((al == -1) && !((pms[0] == (s->client_version >> 8)) &&
1722 	    (pms[1] == (s->client_version & 0xff)))) {
1723 		/*
1724 		 * The premaster secret must contain the same version number
1725 		 * as the ClientHello to detect version rollback attacks
1726 		 * (strangely, the protocol does not offer such protection for
1727 		 * DH ciphersuites).
1728 		 *
1729 		 * The Klima-Pokorny-Rosa extension of Bleichenbacher's attack
1730 		 * (http://eprint.iacr.org/2003/052/) exploits the version
1731 		 * number check as a "bad version oracle" -- an alert would
1732 		 * reveal that the plaintext corresponding to some ciphertext
1733 		 * made up by the adversary is properly formatted except that
1734 		 * the version number is wrong. To avoid such attacks, we should
1735 		 * treat this just like any other decryption error.
1736 		 */
1737 		al = SSL_AD_DECODE_ERROR;
1738 		/* SSLerror(s, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); */
1739 	}
1740 
1741 	if (al != -1) {
1742 		/*
1743 		 * Some decryption failure -- use random value instead
1744 		 * as countermeasure against Bleichenbacher's attack
1745 		 * on PKCS #1 v1.5 RSA padding (see RFC 2246,
1746 		 * section 7.4.7.1).
1747 		 */
1748 		p = fakekey;
1749 	}
1750 
1751 	s->session->master_key_length =
1752 	    tls1_generate_master_secret(s,
1753 	        s->session->master_key, p, SSL_MAX_MASTER_KEY_LENGTH);
1754 
1755 	freezero(pms, pms_len);
1756 
1757 	return (1);
1758 
1759  truncated:
1760 	al = SSL_AD_DECODE_ERROR;
1761 	SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1762  f_err:
1763 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1764  err:
1765 	freezero(pms, pms_len);
1766 
1767 	return (-1);
1768 }
1769 
1770 static int
1771 ssl3_get_client_kex_dhe(SSL *s, CBS *cbs)
1772 {
1773 	int key_size = 0;
1774 	int key_is_invalid, key_len, al;
1775 	unsigned char *key = NULL;
1776 	BIGNUM *bn = NULL;
1777 	CBS dh_Yc;
1778 	DH *dh;
1779 
1780 	if (!CBS_get_u16_length_prefixed(cbs, &dh_Yc))
1781 		goto truncated;
1782 	if (CBS_len(cbs) != 0)
1783 		goto truncated;
1784 
1785 	if (S3I(s)->tmp.dh == NULL) {
1786 		al = SSL_AD_HANDSHAKE_FAILURE;
1787 		SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
1788 		goto f_err;
1789 	}
1790 	dh = S3I(s)->tmp.dh;
1791 
1792 	if ((bn = BN_bin2bn(CBS_data(&dh_Yc), CBS_len(&dh_Yc), NULL)) == NULL) {
1793 		SSLerror(s, SSL_R_BN_LIB);
1794 		goto err;
1795 	}
1796 
1797 	if ((key_size = DH_size(dh)) <= 0) {
1798 		SSLerror(s, ERR_R_DH_LIB);
1799 		goto err;
1800 	}
1801 	if ((key = malloc(key_size)) == NULL) {
1802 		SSLerror(s, ERR_R_MALLOC_FAILURE);
1803 		goto err;
1804 	}
1805 	if (!DH_check_pub_key(dh, bn, &key_is_invalid)) {
1806 		al = SSL_AD_INTERNAL_ERROR;
1807 		SSLerror(s, ERR_R_DH_LIB);
1808 		goto f_err;
1809 	}
1810 	if (key_is_invalid) {
1811 		al = SSL_AD_ILLEGAL_PARAMETER;
1812 		SSLerror(s, ERR_R_DH_LIB);
1813 		goto f_err;
1814 	}
1815 	if ((key_len = DH_compute_key(key, bn, dh)) <= 0) {
1816 		al = SSL_AD_INTERNAL_ERROR;
1817 		SSLerror(s, ERR_R_DH_LIB);
1818 		goto f_err;
1819 	}
1820 
1821 	s->session->master_key_length = tls1_generate_master_secret(s,
1822 	    s->session->master_key, key, key_len);
1823 
1824 	DH_free(S3I(s)->tmp.dh);
1825 	S3I(s)->tmp.dh = NULL;
1826 
1827 	freezero(key, key_size);
1828 	BN_clear_free(bn);
1829 
1830 	return (1);
1831 
1832  truncated:
1833 	al = SSL_AD_DECODE_ERROR;
1834 	SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
1835  f_err:
1836 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
1837  err:
1838 	freezero(key, key_size);
1839 	BN_clear_free(bn);
1840 
1841 	return (-1);
1842 }
1843 
1844 static int
1845 ssl3_get_client_kex_ecdhe_ecp(SSL *s, CBS *cbs)
1846 {
1847 	uint8_t *key = NULL;
1848 	size_t key_len = 0;
1849 	EC_KEY *ecdh_peer = NULL;
1850 	EC_KEY *ecdh;
1851 	CBS public;
1852 	int ret = -1;
1853 
1854 	/*
1855 	 * Use the ephemeral values we saved when generating the
1856 	 * ServerKeyExchange message.
1857 	 */
1858 	if ((ecdh = S3I(s)->tmp.ecdh) == NULL) {
1859 		SSLerror(s, ERR_R_INTERNAL_ERROR);
1860 		goto err;
1861 	}
1862 
1863 	/*
1864 	 * Get client's public key from encoded point in the ClientKeyExchange
1865 	 * message.
1866 	 */
1867 	if (!CBS_get_u8_length_prefixed(cbs, &public))
1868 		goto err;
1869 	if (CBS_len(cbs) != 0)
1870 		goto err;
1871 
1872 	if ((ecdh_peer = EC_KEY_new()) == NULL)
1873 		goto err;
1874 
1875 	if (!ssl_kex_peer_public_ecdhe_ecp(ecdh_peer, S3I(s)->tmp.ecdh_nid,
1876 	    &public))
1877 		goto err;
1878 
1879 	/* Derive the shared secret and compute master secret. */
1880 	if (!ssl_kex_derive_ecdhe_ecp(ecdh, ecdh_peer, &key, &key_len))
1881 		goto err;
1882 	s->session->master_key_length = tls1_generate_master_secret(s,
1883 	    s->session->master_key, key, key_len);
1884 
1885 	EC_KEY_free(S3I(s)->tmp.ecdh);
1886 	S3I(s)->tmp.ecdh = NULL;
1887 	S3I(s)->tmp.ecdh_nid = NID_undef;
1888 
1889 	ret = 1;
1890 
1891  err:
1892 	freezero(key, key_len);
1893 	EC_KEY_free(ecdh_peer);
1894 
1895 	return (ret);
1896 }
1897 
1898 static int
1899 ssl3_get_client_kex_ecdhe_ecx(SSL *s, CBS *cbs)
1900 {
1901 	uint8_t *shared_key = NULL;
1902 	CBS ecpoint;
1903 	int ret = -1;
1904 
1905 	if (!CBS_get_u8_length_prefixed(cbs, &ecpoint))
1906 		goto err;
1907 	if (CBS_len(cbs) != 0)
1908 		goto err;
1909 	if (CBS_len(&ecpoint) != X25519_KEY_LENGTH)
1910 		goto err;
1911 
1912 	if ((shared_key = malloc(X25519_KEY_LENGTH)) == NULL)
1913 		goto err;
1914 	if (!X25519(shared_key, S3I(s)->tmp.x25519, CBS_data(&ecpoint)))
1915 		goto err;
1916 
1917 	freezero(S3I(s)->tmp.x25519, X25519_KEY_LENGTH);
1918 	S3I(s)->tmp.x25519 = NULL;
1919 
1920 	s->session->master_key_length =
1921 	    tls1_generate_master_secret(
1922 		s, s->session->master_key, shared_key, X25519_KEY_LENGTH);
1923 
1924 	ret = 1;
1925 
1926  err:
1927 	freezero(shared_key, X25519_KEY_LENGTH);
1928 
1929 	return (ret);
1930 }
1931 
1932 static int
1933 ssl3_get_client_kex_ecdhe(SSL *s, CBS *cbs)
1934 {
1935         if (S3I(s)->tmp.x25519 != NULL)
1936 		return ssl3_get_client_kex_ecdhe_ecx(s, cbs);
1937 
1938 	return ssl3_get_client_kex_ecdhe_ecp(s, cbs);
1939 }
1940 
1941 static int
1942 ssl3_get_client_kex_gost(SSL *s, CBS *cbs)
1943 {
1944 	EVP_PKEY_CTX *pkey_ctx;
1945 	EVP_PKEY *client_pub_pkey = NULL, *pk = NULL;
1946 	unsigned char premaster_secret[32];
1947 	unsigned long alg_a;
1948 	size_t outlen = 32;
1949 	CBS gostblob;
1950 	int al;
1951 	int ret = 0;
1952 
1953 	/* Get our certificate private key*/
1954 	alg_a = S3I(s)->hs.new_cipher->algorithm_auth;
1955 	if (alg_a & SSL_aGOST01)
1956 		pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
1957 
1958 	if ((pkey_ctx = EVP_PKEY_CTX_new(pk, NULL)) == NULL)
1959 		goto err;
1960 	if (EVP_PKEY_decrypt_init(pkey_ctx) <= 0)
1961 		goto gerr;
1962 
1963 	/*
1964 	 * If client certificate is present and is of the same type,
1965 	 * maybe use it for key exchange.
1966 	 * Don't mind errors from EVP_PKEY_derive_set_peer, because
1967 	 * it is completely valid to use a client certificate for
1968 	 * authorization only.
1969 	 */
1970 	if ((client_pub_pkey = X509_get_pubkey(s->session->peer)) != NULL) {
1971 		if (EVP_PKEY_derive_set_peer(pkey_ctx,
1972 		    client_pub_pkey) <= 0)
1973 			ERR_clear_error();
1974 	}
1975 
1976 	/* Decrypt session key */
1977 	if (!CBS_get_asn1(cbs, &gostblob, CBS_ASN1_SEQUENCE))
1978 		goto truncated;
1979 	if (CBS_len(cbs) != 0)
1980 		goto truncated;
1981 	if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen,
1982 	    CBS_data(&gostblob), CBS_len(&gostblob)) <= 0) {
1983 		SSLerror(s, SSL_R_DECRYPTION_FAILED);
1984 		goto gerr;
1985 	}
1986 
1987 	/* Generate master secret */
1988 	s->session->master_key_length =
1989 	    tls1_generate_master_secret(
1990 		s, s->session->master_key, premaster_secret, 32);
1991 
1992 	/* Check if pubkey from client certificate was used */
1993 	if (EVP_PKEY_CTX_ctrl(pkey_ctx, -1, -1,
1994 	    EVP_PKEY_CTRL_PEER_KEY, 2, NULL) > 0)
1995 		ret = 2;
1996 	else
1997 		ret = 1;
1998  gerr:
1999 	EVP_PKEY_free(client_pub_pkey);
2000 	EVP_PKEY_CTX_free(pkey_ctx);
2001 	if (ret)
2002 		return (ret);
2003 	else
2004 		goto err;
2005 
2006  truncated:
2007 	al = SSL_AD_DECODE_ERROR;
2008 	SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2009 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
2010  err:
2011 	return (-1);
2012 }
2013 
2014 int
2015 ssl3_get_client_key_exchange(SSL *s)
2016 {
2017 	unsigned long alg_k;
2018 	int al, ok;
2019 	CBS cbs;
2020 	long n;
2021 
2022 	/* 2048 maxlen is a guess.  How long a key does that permit? */
2023 	n = ssl3_get_message(s, SSL3_ST_SR_KEY_EXCH_A,
2024 	    SSL3_ST_SR_KEY_EXCH_B, SSL3_MT_CLIENT_KEY_EXCHANGE, 2048, &ok);
2025 	if (!ok)
2026 		return ((int)n);
2027 
2028 	if (n < 0)
2029 		goto err;
2030 
2031 	CBS_init(&cbs, s->internal->init_msg, n);
2032 
2033 	alg_k = S3I(s)->hs.new_cipher->algorithm_mkey;
2034 
2035 	if (alg_k & SSL_kRSA) {
2036 		if (ssl3_get_client_kex_rsa(s, &cbs) != 1)
2037 			goto err;
2038 	} else if (alg_k & SSL_kDHE) {
2039 		if (ssl3_get_client_kex_dhe(s, &cbs) != 1)
2040 			goto err;
2041 	} else if (alg_k & SSL_kECDHE) {
2042 		if (ssl3_get_client_kex_ecdhe(s, &cbs) != 1)
2043 			goto err;
2044 	} else if (alg_k & SSL_kGOST) {
2045 		if (ssl3_get_client_kex_gost(s, &cbs) != 1)
2046 			goto err;
2047 	} else {
2048 		al = SSL_AD_HANDSHAKE_FAILURE;
2049 		SSLerror(s, SSL_R_UNKNOWN_CIPHER_TYPE);
2050 		goto f_err;
2051 	}
2052 
2053 	if (CBS_len(&cbs) != 0) {
2054 		al = SSL_AD_DECODE_ERROR;
2055 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2056 		goto f_err;
2057 	}
2058 
2059 	return (1);
2060 
2061  f_err:
2062 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
2063  err:
2064 	return (-1);
2065 }
2066 
2067 int
2068 ssl3_get_cert_verify(SSL *s)
2069 {
2070 	CBS cbs, signature;
2071 	const struct ssl_sigalg *sigalg = NULL;
2072 	const EVP_MD *md = NULL;
2073 	EVP_PKEY *pkey = NULL;
2074 	X509 *peer = NULL;
2075 	EVP_MD_CTX mctx;
2076 	int al, ok, verify;
2077 	const unsigned char *hdata;
2078 	size_t hdatalen;
2079 	int type = 0;
2080 	int ret = 0;
2081 	long n;
2082 
2083 	EVP_MD_CTX_init(&mctx);
2084 
2085 	n = ssl3_get_message(s, SSL3_ST_SR_CERT_VRFY_A,
2086 	    SSL3_ST_SR_CERT_VRFY_B, -1, SSL3_RT_MAX_PLAIN_LENGTH, &ok);
2087 	if (!ok)
2088 		return ((int)n);
2089 
2090 	if (n < 0)
2091 		goto err;
2092 
2093 	CBS_init(&cbs, s->internal->init_msg, n);
2094 
2095 	if (s->session->peer != NULL) {
2096 		peer = s->session->peer;
2097 		pkey = X509_get_pubkey(peer);
2098 		type = X509_certificate_type(peer, pkey);
2099 	}
2100 
2101 	if (S3I(s)->tmp.message_type != SSL3_MT_CERTIFICATE_VERIFY) {
2102 		S3I(s)->tmp.reuse_message = 1;
2103 		if (peer != NULL) {
2104 			al = SSL_AD_UNEXPECTED_MESSAGE;
2105 			SSLerror(s, SSL_R_MISSING_VERIFY_MESSAGE);
2106 			goto f_err;
2107 		}
2108 		ret = 1;
2109 		goto end;
2110 	}
2111 
2112 	if (peer == NULL) {
2113 		SSLerror(s, SSL_R_NO_CLIENT_CERT_RECEIVED);
2114 		al = SSL_AD_UNEXPECTED_MESSAGE;
2115 		goto f_err;
2116 	}
2117 
2118 	if (!(type & EVP_PKT_SIGN)) {
2119 		SSLerror(s, SSL_R_SIGNATURE_FOR_NON_SIGNING_CERTIFICATE);
2120 		al = SSL_AD_ILLEGAL_PARAMETER;
2121 		goto f_err;
2122 	}
2123 
2124 	if (S3I(s)->change_cipher_spec) {
2125 		SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
2126 		al = SSL_AD_UNEXPECTED_MESSAGE;
2127 		goto f_err;
2128 	}
2129 
2130 	if (!SSL_USE_SIGALGS(s)) {
2131 		if (!CBS_get_u16_length_prefixed(&cbs, &signature))
2132 			goto err;
2133 		if (CBS_len(&signature) > EVP_PKEY_size(pkey)) {
2134 			SSLerror(s, SSL_R_WRONG_SIGNATURE_SIZE);
2135 			al = SSL_AD_DECODE_ERROR;
2136 			goto f_err;
2137 		}
2138 		if (CBS_len(&cbs) != 0) {
2139 			al = SSL_AD_DECODE_ERROR;
2140 			SSLerror(s, SSL_R_EXTRA_DATA_IN_MESSAGE);
2141 			goto f_err;
2142 		}
2143 	}
2144 
2145 	if (SSL_USE_SIGALGS(s)) {
2146 		EVP_PKEY_CTX *pctx;
2147 		uint16_t sigalg_value;
2148 
2149 		if (!CBS_get_u16(&cbs, &sigalg_value))
2150 			goto truncated;
2151 		if ((sigalg = ssl_sigalg(sigalg_value, tls12_sigalgs,
2152 		    tls12_sigalgs_len)) == NULL ||
2153 		    (md = sigalg->md()) == NULL) {
2154 			SSLerror(s, SSL_R_UNKNOWN_DIGEST);
2155 			al = SSL_AD_DECODE_ERROR;
2156 			goto f_err;
2157 		}
2158 		if (!ssl_sigalg_pkey_ok(sigalg, pkey, 0)) {
2159 			SSLerror(s, SSL_R_WRONG_SIGNATURE_TYPE);
2160 			al = SSL_AD_DECODE_ERROR;
2161 			goto f_err;
2162 		}
2163 
2164 		if (!CBS_get_u16_length_prefixed(&cbs, &signature))
2165 			goto err;
2166 		if (CBS_len(&signature) > EVP_PKEY_size(pkey)) {
2167 			SSLerror(s, SSL_R_WRONG_SIGNATURE_SIZE);
2168 			al = SSL_AD_DECODE_ERROR;
2169 			goto f_err;
2170 		}
2171 		if (CBS_len(&cbs) != 0) {
2172 			al = SSL_AD_DECODE_ERROR;
2173 			SSLerror(s, SSL_R_EXTRA_DATA_IN_MESSAGE);
2174 			goto f_err;
2175 		}
2176 
2177 		if (!tls1_transcript_data(s, &hdata, &hdatalen)) {
2178 			SSLerror(s, ERR_R_INTERNAL_ERROR);
2179 			al = SSL_AD_INTERNAL_ERROR;
2180 			goto f_err;
2181 		}
2182 		if (!EVP_DigestVerifyInit(&mctx, &pctx, md, NULL, pkey)) {
2183 			SSLerror(s, ERR_R_EVP_LIB);
2184 			al = SSL_AD_INTERNAL_ERROR;
2185 			goto f_err;
2186 		}
2187 		if ((sigalg->flags & SIGALG_FLAG_RSA_PSS) &&
2188 		    (!EVP_PKEY_CTX_set_rsa_padding
2189 		    (pctx, RSA_PKCS1_PSS_PADDING) ||
2190 		    !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1))) {
2191 			al = SSL_AD_INTERNAL_ERROR;
2192 			goto f_err;
2193 		}
2194 		if (sigalg->key_type == EVP_PKEY_GOSTR01 &&
2195 		    EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_VERIFY,
2196 		    EVP_PKEY_CTRL_GOST_SIG_FORMAT, GOST_SIG_FORMAT_RS_LE,
2197 		    NULL) <= 0) {
2198 			al = SSL_AD_INTERNAL_ERROR;
2199 			goto f_err;
2200 		}
2201 		if (!EVP_DigestVerifyUpdate(&mctx, hdata, hdatalen)) {
2202 			SSLerror(s, ERR_R_EVP_LIB);
2203 			al = SSL_AD_INTERNAL_ERROR;
2204 			goto f_err;
2205 		}
2206 		if (EVP_DigestVerifyFinal(&mctx, CBS_data(&signature),
2207 		    CBS_len(&signature)) <= 0) {
2208 			al = SSL_AD_DECRYPT_ERROR;
2209 			SSLerror(s, SSL_R_BAD_SIGNATURE);
2210 			goto f_err;
2211 		}
2212 	} else if (pkey->type == EVP_PKEY_RSA) {
2213 		verify = RSA_verify(NID_md5_sha1, S3I(s)->tmp.cert_verify_md,
2214 		    MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH, CBS_data(&signature),
2215 		    CBS_len(&signature), pkey->pkey.rsa);
2216 		if (verify < 0) {
2217 			al = SSL_AD_DECRYPT_ERROR;
2218 			SSLerror(s, SSL_R_BAD_RSA_DECRYPT);
2219 			goto f_err;
2220 		}
2221 		if (verify == 0) {
2222 			al = SSL_AD_DECRYPT_ERROR;
2223 			SSLerror(s, SSL_R_BAD_RSA_SIGNATURE);
2224 			goto f_err;
2225 		}
2226 	} else if (pkey->type == EVP_PKEY_EC) {
2227 		verify = ECDSA_verify(pkey->save_type,
2228 		    &(S3I(s)->tmp.cert_verify_md[MD5_DIGEST_LENGTH]),
2229 		    SHA_DIGEST_LENGTH, CBS_data(&signature),
2230 		    CBS_len(&signature), pkey->pkey.ec);
2231 		if (verify <= 0) {
2232 			al = SSL_AD_DECRYPT_ERROR;
2233 			SSLerror(s, SSL_R_BAD_ECDSA_SIGNATURE);
2234 			goto f_err;
2235 		}
2236 #ifndef OPENSSL_NO_GOST
2237 	} else if (pkey->type == NID_id_GostR3410_94 ||
2238 	    pkey->type == NID_id_GostR3410_2001) {
2239 		unsigned char sigbuf[128];
2240 		unsigned int siglen = sizeof(sigbuf);
2241 		EVP_PKEY_CTX *pctx;
2242 		int nid;
2243 
2244 		if (!tls1_transcript_data(s, &hdata, &hdatalen)) {
2245 			SSLerror(s, ERR_R_INTERNAL_ERROR);
2246 			al = SSL_AD_INTERNAL_ERROR;
2247 			goto f_err;
2248 		}
2249 		if (!EVP_PKEY_get_default_digest_nid(pkey, &nid) ||
2250 		    !(md = EVP_get_digestbynid(nid))) {
2251 			SSLerror(s, ERR_R_EVP_LIB);
2252 			al = SSL_AD_INTERNAL_ERROR;
2253 			goto f_err;
2254 		}
2255 		if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL) {
2256 			SSLerror(s, ERR_R_EVP_LIB);
2257 			al = SSL_AD_INTERNAL_ERROR;
2258 			goto f_err;
2259 		}
2260 		if (!EVP_DigestInit_ex(&mctx, md, NULL) ||
2261 		    !EVP_DigestUpdate(&mctx, hdata, hdatalen) ||
2262 		    !EVP_DigestFinal(&mctx, sigbuf, &siglen) ||
2263 		    (EVP_PKEY_verify_init(pctx) <= 0) ||
2264 		    (EVP_PKEY_CTX_set_signature_md(pctx, md) <= 0) ||
2265 		    (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_VERIFY,
2266 		    EVP_PKEY_CTRL_GOST_SIG_FORMAT,
2267 		    GOST_SIG_FORMAT_RS_LE, NULL) <= 0)) {
2268 			SSLerror(s, ERR_R_EVP_LIB);
2269 			al = SSL_AD_INTERNAL_ERROR;
2270 			EVP_PKEY_CTX_free(pctx);
2271 			goto f_err;
2272 		}
2273 		if (EVP_PKEY_verify(pctx, CBS_data(&signature),
2274 		    CBS_len(&signature), sigbuf, siglen) <= 0) {
2275 			al = SSL_AD_DECRYPT_ERROR;
2276 			SSLerror(s, SSL_R_BAD_SIGNATURE);
2277 			EVP_PKEY_CTX_free(pctx);
2278 			goto f_err;
2279 		}
2280 
2281 		EVP_PKEY_CTX_free(pctx);
2282 #endif
2283 	} else {
2284 		SSLerror(s, ERR_R_INTERNAL_ERROR);
2285 		al = SSL_AD_UNSUPPORTED_CERTIFICATE;
2286 		goto f_err;
2287 	}
2288 
2289 	ret = 1;
2290 	if (0) {
2291  truncated:
2292 		al = SSL_AD_DECODE_ERROR;
2293 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2294  f_err:
2295 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
2296 	}
2297  end:
2298 	tls1_transcript_free(s);
2299  err:
2300 	EVP_MD_CTX_cleanup(&mctx);
2301 	EVP_PKEY_free(pkey);
2302 	return (ret);
2303 }
2304 
2305 int
2306 ssl3_get_client_certificate(SSL *s)
2307 {
2308 	CBS cbs, client_certs;
2309 	int i, ok, al, ret = -1;
2310 	X509 *x = NULL;
2311 	long n;
2312 	const unsigned char *q;
2313 	STACK_OF(X509) *sk = NULL;
2314 
2315 	n = ssl3_get_message(s, SSL3_ST_SR_CERT_A, SSL3_ST_SR_CERT_B,
2316 	    -1, s->internal->max_cert_list, &ok);
2317 	if (!ok)
2318 		return ((int)n);
2319 
2320 	if (S3I(s)->tmp.message_type == SSL3_MT_CLIENT_KEY_EXCHANGE) {
2321 		if ((s->verify_mode & SSL_VERIFY_PEER) &&
2322 		    (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
2323 		    	SSLerror(s, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
2324 			al = SSL_AD_HANDSHAKE_FAILURE;
2325 			goto f_err;
2326 		}
2327 		/*
2328 		 * If tls asked for a client cert,
2329 		 * the client must return a 0 list.
2330 		 */
2331 		if (S3I(s)->tmp.cert_request) {
2332 			SSLerror(s, SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST
2333 			    );
2334 			al = SSL_AD_UNEXPECTED_MESSAGE;
2335 			goto f_err;
2336 		}
2337 		S3I(s)->tmp.reuse_message = 1;
2338 		return (1);
2339 	}
2340 
2341 	if (S3I(s)->tmp.message_type != SSL3_MT_CERTIFICATE) {
2342 		al = SSL_AD_UNEXPECTED_MESSAGE;
2343 		SSLerror(s, SSL_R_WRONG_MESSAGE_TYPE);
2344 		goto f_err;
2345 	}
2346 
2347 	if (n < 0)
2348 		goto truncated;
2349 
2350 	CBS_init(&cbs, s->internal->init_msg, n);
2351 
2352 	if ((sk = sk_X509_new_null()) == NULL) {
2353 		SSLerror(s, ERR_R_MALLOC_FAILURE);
2354 		goto err;
2355 	}
2356 
2357 	if (!CBS_get_u24_length_prefixed(&cbs, &client_certs) ||
2358 	    CBS_len(&cbs) != 0)
2359 		goto truncated;
2360 
2361 	while (CBS_len(&client_certs) > 0) {
2362 		CBS cert;
2363 
2364 		if (!CBS_get_u24_length_prefixed(&client_certs, &cert)) {
2365 			al = SSL_AD_DECODE_ERROR;
2366 			SSLerror(s, SSL_R_CERT_LENGTH_MISMATCH);
2367 			goto f_err;
2368 		}
2369 
2370 		q = CBS_data(&cert);
2371 		x = d2i_X509(NULL, &q, CBS_len(&cert));
2372 		if (x == NULL) {
2373 			SSLerror(s, ERR_R_ASN1_LIB);
2374 			goto err;
2375 		}
2376 		if (q != CBS_data(&cert) + CBS_len(&cert)) {
2377 			al = SSL_AD_DECODE_ERROR;
2378 			SSLerror(s, SSL_R_CERT_LENGTH_MISMATCH);
2379 			goto f_err;
2380 		}
2381 		if (!sk_X509_push(sk, x)) {
2382 			SSLerror(s, ERR_R_MALLOC_FAILURE);
2383 			goto err;
2384 		}
2385 		x = NULL;
2386 	}
2387 
2388 	if (sk_X509_num(sk) <= 0) {
2389 		/*
2390 		 * TLS does not mind 0 certs returned.
2391 		 * Fail for TLS only if we required a certificate.
2392 		 */
2393 		if ((s->verify_mode & SSL_VERIFY_PEER) &&
2394 		    (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
2395 			SSLerror(s, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
2396 			al = SSL_AD_HANDSHAKE_FAILURE;
2397 			goto f_err;
2398 		}
2399 		/* No client certificate so free transcript. */
2400 		tls1_transcript_free(s);
2401 	} else {
2402 		i = ssl_verify_cert_chain(s, sk);
2403 		if (i <= 0) {
2404 			al = ssl_verify_alarm_type(s->verify_result);
2405 			SSLerror(s, SSL_R_NO_CERTIFICATE_RETURNED);
2406 			goto f_err;
2407 		}
2408 	}
2409 
2410 	X509_free(s->session->peer);
2411 	s->session->peer = sk_X509_shift(sk);
2412 	s->session->verify_result = s->verify_result;
2413 
2414 	/*
2415 	 * With the current implementation, sess_cert will always be NULL
2416 	 * when we arrive here
2417 	 */
2418 	if (SSI(s)->sess_cert == NULL) {
2419 		SSI(s)->sess_cert = ssl_sess_cert_new();
2420 		if (SSI(s)->sess_cert == NULL) {
2421 			SSLerror(s, ERR_R_MALLOC_FAILURE);
2422 			goto err;
2423 		}
2424 	}
2425 	sk_X509_pop_free(SSI(s)->sess_cert->cert_chain, X509_free);
2426 	SSI(s)->sess_cert->cert_chain = sk;
2427 
2428 	/*
2429 	 * Inconsistency alert: cert_chain does *not* include the
2430 	 * peer's own certificate, while we do include it in s3_clnt.c
2431 	 */
2432 
2433 	sk = NULL;
2434 
2435 	ret = 1;
2436 	if (0) {
2437 truncated:
2438 		al = SSL_AD_DECODE_ERROR;
2439 		SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
2440 f_err:
2441 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
2442 	}
2443 err:
2444 	X509_free(x);
2445 	sk_X509_pop_free(sk, X509_free);
2446 
2447 	return (ret);
2448 }
2449 
2450 int
2451 ssl3_send_server_certificate(SSL *s)
2452 {
2453 	CBB cbb, server_cert;
2454 	CERT_PKEY *cpk;
2455 
2456 	/*
2457 	 * Server Certificate - RFC 5246, section 7.4.2.
2458 	 */
2459 
2460 	memset(&cbb, 0, sizeof(cbb));
2461 
2462 	if (S3I(s)->hs.state == SSL3_ST_SW_CERT_A) {
2463 		if ((cpk = ssl_get_server_send_pkey(s)) == NULL) {
2464 			SSLerror(s, ERR_R_INTERNAL_ERROR);
2465 			return (0);
2466 		}
2467 
2468 		if (!ssl3_handshake_msg_start(s, &cbb, &server_cert,
2469 		    SSL3_MT_CERTIFICATE))
2470 			goto err;
2471 		if (!ssl3_output_cert_chain(s, &server_cert, cpk))
2472 			goto err;
2473 		if (!ssl3_handshake_msg_finish(s, &cbb))
2474 			goto err;
2475 
2476 		S3I(s)->hs.state = SSL3_ST_SW_CERT_B;
2477 	}
2478 
2479 	/* SSL3_ST_SW_CERT_B */
2480 	return (ssl3_handshake_write(s));
2481 
2482  err:
2483 	CBB_cleanup(&cbb);
2484 
2485 	return (0);
2486 }
2487 
2488 /* send a new session ticket (not necessarily for a new session) */
2489 int
2490 ssl3_send_newsession_ticket(SSL *s)
2491 {
2492 	CBB cbb, session_ticket, ticket;
2493 	SSL_CTX *tctx = s->initial_ctx;
2494 	size_t enc_session_len, enc_session_max_len, hmac_len;
2495 	size_t session_len = 0;
2496 	unsigned char *enc_session = NULL, *session = NULL;
2497 	unsigned char iv[EVP_MAX_IV_LENGTH];
2498 	unsigned char key_name[16];
2499 	unsigned char *hmac;
2500 	unsigned int hlen;
2501 	EVP_CIPHER_CTX ctx;
2502 	HMAC_CTX hctx;
2503 	int len;
2504 
2505 	/*
2506 	 * New Session Ticket - RFC 5077, section 3.3.
2507 	 */
2508 
2509 	EVP_CIPHER_CTX_init(&ctx);
2510 	HMAC_CTX_init(&hctx);
2511 
2512 	memset(&cbb, 0, sizeof(cbb));
2513 
2514 	if (S3I(s)->hs.state == SSL3_ST_SW_SESSION_TICKET_A) {
2515 		if (!ssl3_handshake_msg_start(s, &cbb, &session_ticket,
2516 		    SSL3_MT_NEWSESSION_TICKET))
2517 			goto err;
2518 
2519 		if (!SSL_SESSION_ticket(s->session, &session, &session_len))
2520 			goto err;
2521 		if (session_len > 0xffff)
2522 			goto err;
2523 
2524 		/*
2525 		 * Initialize HMAC and cipher contexts. If callback is present
2526 		 * it does all the work, otherwise use generated values from
2527 		 * parent context.
2528 		 */
2529 		if (tctx->internal->tlsext_ticket_key_cb != NULL) {
2530 			if (tctx->internal->tlsext_ticket_key_cb(s,
2531 			    key_name, iv, &ctx, &hctx, 1) < 0) {
2532 				EVP_CIPHER_CTX_cleanup(&ctx);
2533 				goto err;
2534 			}
2535 		} else {
2536 			arc4random_buf(iv, 16);
2537 			EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL,
2538 			    tctx->internal->tlsext_tick_aes_key, iv);
2539 			HMAC_Init_ex(&hctx, tctx->internal->tlsext_tick_hmac_key,
2540 			    16, EVP_sha256(), NULL);
2541 			memcpy(key_name, tctx->internal->tlsext_tick_key_name, 16);
2542 		}
2543 
2544 		/* Encrypt the session state. */
2545 		enc_session_max_len = session_len + EVP_MAX_BLOCK_LENGTH;
2546 		if ((enc_session = calloc(1, enc_session_max_len)) == NULL)
2547 			goto err;
2548 		enc_session_len = 0;
2549 		if (!EVP_EncryptUpdate(&ctx, enc_session, &len, session,
2550 		    session_len))
2551 			goto err;
2552 		enc_session_len += len;
2553 		if (!EVP_EncryptFinal_ex(&ctx, enc_session + enc_session_len,
2554 		    &len))
2555 			goto err;
2556 		enc_session_len += len;
2557 
2558 		if (enc_session_len > enc_session_max_len)
2559 			goto err;
2560 
2561 		/* Generate the HMAC. */
2562 		if (!HMAC_Update(&hctx, key_name, sizeof(key_name)))
2563 			goto err;
2564 		if (!HMAC_Update(&hctx, iv, EVP_CIPHER_CTX_iv_length(&ctx)))
2565 			goto err;
2566 		if (!HMAC_Update(&hctx, enc_session, enc_session_len))
2567 			goto err;
2568 
2569 		if ((hmac_len = HMAC_size(&hctx)) <= 0)
2570 			goto err;
2571 
2572 		/*
2573 		 * Ticket lifetime hint (advisory only):
2574 		 * We leave this unspecified for resumed session
2575 		 * (for simplicity), and guess that tickets for new
2576 		 * sessions will live as long as their sessions.
2577 		 */
2578 		if (!CBB_add_u32(&session_ticket,
2579 		    s->internal->hit ? 0 : s->session->timeout))
2580 			goto err;
2581 
2582 		if (!CBB_add_u16_length_prefixed(&session_ticket, &ticket))
2583 			goto err;
2584 		if (!CBB_add_bytes(&ticket, key_name, sizeof(key_name)))
2585 			goto err;
2586 		if (!CBB_add_bytes(&ticket, iv, EVP_CIPHER_CTX_iv_length(&ctx)))
2587 			goto err;
2588 		if (!CBB_add_bytes(&ticket, enc_session, enc_session_len))
2589 			goto err;
2590 		if (!CBB_add_space(&ticket, &hmac, hmac_len))
2591 			goto err;
2592 
2593 		if (!HMAC_Final(&hctx, hmac, &hlen))
2594 			goto err;
2595 		if (hlen != hmac_len)
2596 			goto err;
2597 
2598 		if (!ssl3_handshake_msg_finish(s, &cbb))
2599 			goto err;
2600 
2601 		S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_B;
2602 	}
2603 
2604 	EVP_CIPHER_CTX_cleanup(&ctx);
2605 	HMAC_CTX_cleanup(&hctx);
2606 	freezero(session, session_len);
2607 	free(enc_session);
2608 
2609 	/* SSL3_ST_SW_SESSION_TICKET_B */
2610 	return (ssl3_handshake_write(s));
2611 
2612  err:
2613 	CBB_cleanup(&cbb);
2614 	EVP_CIPHER_CTX_cleanup(&ctx);
2615 	HMAC_CTX_cleanup(&hctx);
2616 	freezero(session, session_len);
2617 	free(enc_session);
2618 
2619 	return (-1);
2620 }
2621 
2622 int
2623 ssl3_send_cert_status(SSL *s)
2624 {
2625 	CBB cbb, certstatus, ocspresp;
2626 
2627 	memset(&cbb, 0, sizeof(cbb));
2628 
2629 	if (S3I(s)->hs.state == SSL3_ST_SW_CERT_STATUS_A) {
2630 		if (!ssl3_handshake_msg_start(s, &cbb, &certstatus,
2631 		    SSL3_MT_CERTIFICATE_STATUS))
2632 			goto err;
2633 		if (!CBB_add_u8(&certstatus, s->tlsext_status_type))
2634 			goto err;
2635 		if (!CBB_add_u24_length_prefixed(&certstatus, &ocspresp))
2636 			goto err;
2637 		if (!CBB_add_bytes(&ocspresp, s->internal->tlsext_ocsp_resp,
2638 		    s->internal->tlsext_ocsp_resp_len))
2639 			goto err;
2640 		if (!ssl3_handshake_msg_finish(s, &cbb))
2641 			goto err;
2642 
2643 		S3I(s)->hs.state = SSL3_ST_SW_CERT_STATUS_B;
2644 	}
2645 
2646 	/* SSL3_ST_SW_CERT_STATUS_B */
2647 	return (ssl3_handshake_write(s));
2648 
2649  err:
2650 	CBB_cleanup(&cbb);
2651 
2652 	return (-1);
2653 }
2654