xref: /freebsd/crypto/openssl/ssl/statem/statem_srvr.c (revision e4456411a8c2d4a9bfbccd60f2cf914fd402f817)
1 /*
2  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
3  * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4  * Copyright 2005 Nokia. All rights reserved.
5  *
6  * Licensed under the OpenSSL license (the "License").  You may not use
7  * this file except in compliance with the License.  You can obtain a copy
8  * in the file LICENSE in the source distribution or at
9  * https://www.openssl.org/source/license.html
10  */
11 
12 #include <stdio.h>
13 #include "../ssl_locl.h"
14 #include "statem_locl.h"
15 #include "internal/constant_time_locl.h"
16 #include "internal/cryptlib.h"
17 #include <openssl/buffer.h>
18 #include <openssl/rand.h>
19 #include <openssl/objects.h>
20 #include <openssl/evp.h>
21 #include <openssl/hmac.h>
22 #include <openssl/x509.h>
23 #include <openssl/dh.h>
24 #include <openssl/bn.h>
25 #include <openssl/md5.h>
26 
27 #define TICKET_NONCE_SIZE       8
28 
29 static int tls_construct_encrypted_extensions(SSL *s, WPACKET *pkt);
30 
31 /*
32  * ossl_statem_server13_read_transition() encapsulates the logic for the allowed
33  * handshake state transitions when a TLSv1.3 server is reading messages from
34  * the client. The message type that the client has sent is provided in |mt|.
35  * The current state is in |s->statem.hand_state|.
36  *
37  * Return values are 1 for success (transition allowed) and  0 on error
38  * (transition not allowed)
39  */
40 static int ossl_statem_server13_read_transition(SSL *s, int mt)
41 {
42     OSSL_STATEM *st = &s->statem;
43 
44     /*
45      * Note: There is no case for TLS_ST_BEFORE because at that stage we have
46      * not negotiated TLSv1.3 yet, so that case is handled by
47      * ossl_statem_server_read_transition()
48      */
49     switch (st->hand_state) {
50     default:
51         break;
52 
53     case TLS_ST_EARLY_DATA:
54         if (s->hello_retry_request == SSL_HRR_PENDING) {
55             if (mt == SSL3_MT_CLIENT_HELLO) {
56                 st->hand_state = TLS_ST_SR_CLNT_HELLO;
57                 return 1;
58             }
59             break;
60         } else if (s->ext.early_data == SSL_EARLY_DATA_ACCEPTED) {
61             if (mt == SSL3_MT_END_OF_EARLY_DATA) {
62                 st->hand_state = TLS_ST_SR_END_OF_EARLY_DATA;
63                 return 1;
64             }
65             break;
66         }
67         /* Fall through */
68 
69     case TLS_ST_SR_END_OF_EARLY_DATA:
70     case TLS_ST_SW_FINISHED:
71         if (s->s3->tmp.cert_request) {
72             if (mt == SSL3_MT_CERTIFICATE) {
73                 st->hand_state = TLS_ST_SR_CERT;
74                 return 1;
75             }
76         } else {
77             if (mt == SSL3_MT_FINISHED) {
78                 st->hand_state = TLS_ST_SR_FINISHED;
79                 return 1;
80             }
81         }
82         break;
83 
84     case TLS_ST_SR_CERT:
85         if (s->session->peer == NULL) {
86             if (mt == SSL3_MT_FINISHED) {
87                 st->hand_state = TLS_ST_SR_FINISHED;
88                 return 1;
89             }
90         } else {
91             if (mt == SSL3_MT_CERTIFICATE_VERIFY) {
92                 st->hand_state = TLS_ST_SR_CERT_VRFY;
93                 return 1;
94             }
95         }
96         break;
97 
98     case TLS_ST_SR_CERT_VRFY:
99         if (mt == SSL3_MT_FINISHED) {
100             st->hand_state = TLS_ST_SR_FINISHED;
101             return 1;
102         }
103         break;
104 
105     case TLS_ST_OK:
106         /*
107          * Its never ok to start processing handshake messages in the middle of
108          * early data (i.e. before we've received the end of early data alert)
109          */
110         if (s->early_data_state == SSL_EARLY_DATA_READING)
111             break;
112 
113         if (mt == SSL3_MT_CERTIFICATE
114                 && s->post_handshake_auth == SSL_PHA_REQUESTED) {
115             st->hand_state = TLS_ST_SR_CERT;
116             return 1;
117         }
118 
119         if (mt == SSL3_MT_KEY_UPDATE) {
120             st->hand_state = TLS_ST_SR_KEY_UPDATE;
121             return 1;
122         }
123         break;
124     }
125 
126     /* No valid transition found */
127     return 0;
128 }
129 
130 /*
131  * ossl_statem_server_read_transition() encapsulates the logic for the allowed
132  * handshake state transitions when the server is reading messages from the
133  * client. The message type that the client has sent is provided in |mt|. The
134  * current state is in |s->statem.hand_state|.
135  *
136  * Return values are 1 for success (transition allowed) and  0 on error
137  * (transition not allowed)
138  */
139 int ossl_statem_server_read_transition(SSL *s, int mt)
140 {
141     OSSL_STATEM *st = &s->statem;
142 
143     if (SSL_IS_TLS13(s)) {
144         if (!ossl_statem_server13_read_transition(s, mt))
145             goto err;
146         return 1;
147     }
148 
149     switch (st->hand_state) {
150     default:
151         break;
152 
153     case TLS_ST_BEFORE:
154     case TLS_ST_OK:
155     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
156         if (mt == SSL3_MT_CLIENT_HELLO) {
157             st->hand_state = TLS_ST_SR_CLNT_HELLO;
158             return 1;
159         }
160         break;
161 
162     case TLS_ST_SW_SRVR_DONE:
163         /*
164          * If we get a CKE message after a ServerDone then either
165          * 1) We didn't request a Certificate
166          * OR
167          * 2) If we did request one then
168          *      a) We allow no Certificate to be returned
169          *      AND
170          *      b) We are running SSL3 (in TLS1.0+ the client must return a 0
171          *         list if we requested a certificate)
172          */
173         if (mt == SSL3_MT_CLIENT_KEY_EXCHANGE) {
174             if (s->s3->tmp.cert_request) {
175                 if (s->version == SSL3_VERSION) {
176                     if ((s->verify_mode & SSL_VERIFY_PEER)
177                         && (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
178                         /*
179                          * This isn't an unexpected message as such - we're just
180                          * not going to accept it because we require a client
181                          * cert.
182                          */
183                         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
184                                  SSL_F_OSSL_STATEM_SERVER_READ_TRANSITION,
185                                  SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
186                         return 0;
187                     }
188                     st->hand_state = TLS_ST_SR_KEY_EXCH;
189                     return 1;
190                 }
191             } else {
192                 st->hand_state = TLS_ST_SR_KEY_EXCH;
193                 return 1;
194             }
195         } else if (s->s3->tmp.cert_request) {
196             if (mt == SSL3_MT_CERTIFICATE) {
197                 st->hand_state = TLS_ST_SR_CERT;
198                 return 1;
199             }
200         }
201         break;
202 
203     case TLS_ST_SR_CERT:
204         if (mt == SSL3_MT_CLIENT_KEY_EXCHANGE) {
205             st->hand_state = TLS_ST_SR_KEY_EXCH;
206             return 1;
207         }
208         break;
209 
210     case TLS_ST_SR_KEY_EXCH:
211         /*
212          * We should only process a CertificateVerify message if we have
213          * received a Certificate from the client. If so then |s->session->peer|
214          * will be non NULL. In some instances a CertificateVerify message is
215          * not required even if the peer has sent a Certificate (e.g. such as in
216          * the case of static DH). In that case |st->no_cert_verify| should be
217          * set.
218          */
219         if (s->session->peer == NULL || st->no_cert_verify) {
220             if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
221                 /*
222                  * For the ECDH ciphersuites when the client sends its ECDH
223                  * pub key in a certificate, the CertificateVerify message is
224                  * not sent. Also for GOST ciphersuites when the client uses
225                  * its key from the certificate for key exchange.
226                  */
227                 st->hand_state = TLS_ST_SR_CHANGE;
228                 return 1;
229             }
230         } else {
231             if (mt == SSL3_MT_CERTIFICATE_VERIFY) {
232                 st->hand_state = TLS_ST_SR_CERT_VRFY;
233                 return 1;
234             }
235         }
236         break;
237 
238     case TLS_ST_SR_CERT_VRFY:
239         if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
240             st->hand_state = TLS_ST_SR_CHANGE;
241             return 1;
242         }
243         break;
244 
245     case TLS_ST_SR_CHANGE:
246 #ifndef OPENSSL_NO_NEXTPROTONEG
247         if (s->s3->npn_seen) {
248             if (mt == SSL3_MT_NEXT_PROTO) {
249                 st->hand_state = TLS_ST_SR_NEXT_PROTO;
250                 return 1;
251             }
252         } else {
253 #endif
254             if (mt == SSL3_MT_FINISHED) {
255                 st->hand_state = TLS_ST_SR_FINISHED;
256                 return 1;
257             }
258 #ifndef OPENSSL_NO_NEXTPROTONEG
259         }
260 #endif
261         break;
262 
263 #ifndef OPENSSL_NO_NEXTPROTONEG
264     case TLS_ST_SR_NEXT_PROTO:
265         if (mt == SSL3_MT_FINISHED) {
266             st->hand_state = TLS_ST_SR_FINISHED;
267             return 1;
268         }
269         break;
270 #endif
271 
272     case TLS_ST_SW_FINISHED:
273         if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
274             st->hand_state = TLS_ST_SR_CHANGE;
275             return 1;
276         }
277         break;
278     }
279 
280  err:
281     /* No valid transition found */
282     if (SSL_IS_DTLS(s) && mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
283         BIO *rbio;
284 
285         /*
286          * CCS messages don't have a message sequence number so this is probably
287          * because of an out-of-order CCS. We'll just drop it.
288          */
289         s->init_num = 0;
290         s->rwstate = SSL_READING;
291         rbio = SSL_get_rbio(s);
292         BIO_clear_retry_flags(rbio);
293         BIO_set_retry_read(rbio);
294         return 0;
295     }
296     SSLfatal(s, SSL3_AD_UNEXPECTED_MESSAGE,
297              SSL_F_OSSL_STATEM_SERVER_READ_TRANSITION,
298              SSL_R_UNEXPECTED_MESSAGE);
299     return 0;
300 }
301 
302 /*
303  * Should we send a ServerKeyExchange message?
304  *
305  * Valid return values are:
306  *   1: Yes
307  *   0: No
308  */
309 static int send_server_key_exchange(SSL *s)
310 {
311     unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
312 
313     /*
314      * only send a ServerKeyExchange if DH or fortezza but we have a
315      * sign only certificate PSK: may send PSK identity hints For
316      * ECC ciphersuites, we send a serverKeyExchange message only if
317      * the cipher suite is either ECDH-anon or ECDHE. In other cases,
318      * the server certificate contains the server's public key for
319      * key exchange.
320      */
321     if (alg_k & (SSL_kDHE | SSL_kECDHE)
322         /*
323          * PSK: send ServerKeyExchange if PSK identity hint if
324          * provided
325          */
326 #ifndef OPENSSL_NO_PSK
327         /* Only send SKE if we have identity hint for plain PSK */
328         || ((alg_k & (SSL_kPSK | SSL_kRSAPSK))
329             && s->cert->psk_identity_hint)
330         /* For other PSK always send SKE */
331         || (alg_k & (SSL_PSK & (SSL_kDHEPSK | SSL_kECDHEPSK)))
332 #endif
333 #ifndef OPENSSL_NO_SRP
334         /* SRP: send ServerKeyExchange */
335         || (alg_k & SSL_kSRP)
336 #endif
337         ) {
338         return 1;
339     }
340 
341     return 0;
342 }
343 
344 /*
345  * Should we send a CertificateRequest message?
346  *
347  * Valid return values are:
348  *   1: Yes
349  *   0: No
350  */
351 int send_certificate_request(SSL *s)
352 {
353     if (
354            /* don't request cert unless asked for it: */
355            s->verify_mode & SSL_VERIFY_PEER
356            /*
357             * don't request if post-handshake-only unless doing
358             * post-handshake in TLSv1.3:
359             */
360            && (!SSL_IS_TLS13(s) || !(s->verify_mode & SSL_VERIFY_POST_HANDSHAKE)
361                || s->post_handshake_auth == SSL_PHA_REQUEST_PENDING)
362            /*
363             * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
364             * a second time:
365             */
366            && (s->certreqs_sent < 1 ||
367                !(s->verify_mode & SSL_VERIFY_CLIENT_ONCE))
368            /*
369             * never request cert in anonymous ciphersuites (see
370             * section "Certificate request" in SSL 3 drafts and in
371             * RFC 2246):
372             */
373            && (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
374                /*
375                 * ... except when the application insists on
376                 * verification (against the specs, but statem_clnt.c accepts
377                 * this for SSL 3)
378                 */
379                || (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
380            /* don't request certificate for SRP auth */
381            && !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aSRP)
382            /*
383             * With normal PSK Certificates and Certificate Requests
384             * are omitted
385             */
386            && !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aPSK)) {
387         return 1;
388     }
389 
390     return 0;
391 }
392 
393 /*
394  * ossl_statem_server13_write_transition() works out what handshake state to
395  * move to next when a TLSv1.3 server is writing messages to be sent to the
396  * client.
397  */
398 static WRITE_TRAN ossl_statem_server13_write_transition(SSL *s)
399 {
400     OSSL_STATEM *st = &s->statem;
401 
402     /*
403      * No case for TLS_ST_BEFORE, because at that stage we have not negotiated
404      * TLSv1.3 yet, so that is handled by ossl_statem_server_write_transition()
405      */
406 
407     switch (st->hand_state) {
408     default:
409         /* Shouldn't happen */
410         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
411                  SSL_F_OSSL_STATEM_SERVER13_WRITE_TRANSITION,
412                  ERR_R_INTERNAL_ERROR);
413         return WRITE_TRAN_ERROR;
414 
415     case TLS_ST_OK:
416         if (s->key_update != SSL_KEY_UPDATE_NONE) {
417             st->hand_state = TLS_ST_SW_KEY_UPDATE;
418             return WRITE_TRAN_CONTINUE;
419         }
420         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
421             st->hand_state = TLS_ST_SW_CERT_REQ;
422             return WRITE_TRAN_CONTINUE;
423         }
424         /* Try to read from the client instead */
425         return WRITE_TRAN_FINISHED;
426 
427     case TLS_ST_SR_CLNT_HELLO:
428         st->hand_state = TLS_ST_SW_SRVR_HELLO;
429         return WRITE_TRAN_CONTINUE;
430 
431     case TLS_ST_SW_SRVR_HELLO:
432         if ((s->options & SSL_OP_ENABLE_MIDDLEBOX_COMPAT) != 0
433                 && s->hello_retry_request != SSL_HRR_COMPLETE)
434             st->hand_state = TLS_ST_SW_CHANGE;
435         else if (s->hello_retry_request == SSL_HRR_PENDING)
436             st->hand_state = TLS_ST_EARLY_DATA;
437         else
438             st->hand_state = TLS_ST_SW_ENCRYPTED_EXTENSIONS;
439         return WRITE_TRAN_CONTINUE;
440 
441     case TLS_ST_SW_CHANGE:
442         if (s->hello_retry_request == SSL_HRR_PENDING)
443             st->hand_state = TLS_ST_EARLY_DATA;
444         else
445             st->hand_state = TLS_ST_SW_ENCRYPTED_EXTENSIONS;
446         return WRITE_TRAN_CONTINUE;
447 
448     case TLS_ST_SW_ENCRYPTED_EXTENSIONS:
449         if (s->hit)
450             st->hand_state = TLS_ST_SW_FINISHED;
451         else if (send_certificate_request(s))
452             st->hand_state = TLS_ST_SW_CERT_REQ;
453         else
454             st->hand_state = TLS_ST_SW_CERT;
455 
456         return WRITE_TRAN_CONTINUE;
457 
458     case TLS_ST_SW_CERT_REQ:
459         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
460             s->post_handshake_auth = SSL_PHA_REQUESTED;
461             st->hand_state = TLS_ST_OK;
462         } else {
463             st->hand_state = TLS_ST_SW_CERT;
464         }
465         return WRITE_TRAN_CONTINUE;
466 
467     case TLS_ST_SW_CERT:
468         st->hand_state = TLS_ST_SW_CERT_VRFY;
469         return WRITE_TRAN_CONTINUE;
470 
471     case TLS_ST_SW_CERT_VRFY:
472         st->hand_state = TLS_ST_SW_FINISHED;
473         return WRITE_TRAN_CONTINUE;
474 
475     case TLS_ST_SW_FINISHED:
476         st->hand_state = TLS_ST_EARLY_DATA;
477         return WRITE_TRAN_CONTINUE;
478 
479     case TLS_ST_EARLY_DATA:
480         return WRITE_TRAN_FINISHED;
481 
482     case TLS_ST_SR_FINISHED:
483         /*
484          * Technically we have finished the handshake at this point, but we're
485          * going to remain "in_init" for now and write out any session tickets
486          * immediately.
487          */
488         if (s->post_handshake_auth == SSL_PHA_REQUESTED) {
489             s->post_handshake_auth = SSL_PHA_EXT_RECEIVED;
490         } else if (!s->ext.ticket_expected) {
491             /*
492              * If we're not going to renew the ticket then we just finish the
493              * handshake at this point.
494              */
495             st->hand_state = TLS_ST_OK;
496             return WRITE_TRAN_CONTINUE;
497         }
498         if (s->num_tickets > s->sent_tickets)
499             st->hand_state = TLS_ST_SW_SESSION_TICKET;
500         else
501             st->hand_state = TLS_ST_OK;
502         return WRITE_TRAN_CONTINUE;
503 
504     case TLS_ST_SR_KEY_UPDATE:
505         if (s->key_update != SSL_KEY_UPDATE_NONE) {
506             st->hand_state = TLS_ST_SW_KEY_UPDATE;
507             return WRITE_TRAN_CONTINUE;
508         }
509         /* Fall through */
510 
511     case TLS_ST_SW_KEY_UPDATE:
512         st->hand_state = TLS_ST_OK;
513         return WRITE_TRAN_CONTINUE;
514 
515     case TLS_ST_SW_SESSION_TICKET:
516         /* In a resumption we only ever send a maximum of one new ticket.
517          * Following an initial handshake we send the number of tickets we have
518          * been configured for.
519          */
520         if (s->hit || s->num_tickets <= s->sent_tickets) {
521             /* We've written enough tickets out. */
522             st->hand_state = TLS_ST_OK;
523         }
524         return WRITE_TRAN_CONTINUE;
525     }
526 }
527 
528 /*
529  * ossl_statem_server_write_transition() works out what handshake state to move
530  * to next when the server is writing messages to be sent to the client.
531  */
532 WRITE_TRAN ossl_statem_server_write_transition(SSL *s)
533 {
534     OSSL_STATEM *st = &s->statem;
535 
536     /*
537      * Note that before the ClientHello we don't know what version we are going
538      * to negotiate yet, so we don't take this branch until later
539      */
540 
541     if (SSL_IS_TLS13(s))
542         return ossl_statem_server13_write_transition(s);
543 
544     switch (st->hand_state) {
545     default:
546         /* Shouldn't happen */
547         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
548                  SSL_F_OSSL_STATEM_SERVER_WRITE_TRANSITION,
549                  ERR_R_INTERNAL_ERROR);
550         return WRITE_TRAN_ERROR;
551 
552     case TLS_ST_OK:
553         if (st->request_state == TLS_ST_SW_HELLO_REQ) {
554             /* We must be trying to renegotiate */
555             st->hand_state = TLS_ST_SW_HELLO_REQ;
556             st->request_state = TLS_ST_BEFORE;
557             return WRITE_TRAN_CONTINUE;
558         }
559         /* Must be an incoming ClientHello */
560         if (!tls_setup_handshake(s)) {
561             /* SSLfatal() already called */
562             return WRITE_TRAN_ERROR;
563         }
564         /* Fall through */
565 
566     case TLS_ST_BEFORE:
567         /* Just go straight to trying to read from the client */
568         return WRITE_TRAN_FINISHED;
569 
570     case TLS_ST_SW_HELLO_REQ:
571         st->hand_state = TLS_ST_OK;
572         return WRITE_TRAN_CONTINUE;
573 
574     case TLS_ST_SR_CLNT_HELLO:
575         if (SSL_IS_DTLS(s) && !s->d1->cookie_verified
576             && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE)) {
577             st->hand_state = DTLS_ST_SW_HELLO_VERIFY_REQUEST;
578         } else if (s->renegotiate == 0 && !SSL_IS_FIRST_HANDSHAKE(s)) {
579             /* We must have rejected the renegotiation */
580             st->hand_state = TLS_ST_OK;
581             return WRITE_TRAN_CONTINUE;
582         } else {
583             st->hand_state = TLS_ST_SW_SRVR_HELLO;
584         }
585         return WRITE_TRAN_CONTINUE;
586 
587     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
588         return WRITE_TRAN_FINISHED;
589 
590     case TLS_ST_SW_SRVR_HELLO:
591         if (s->hit) {
592             if (s->ext.ticket_expected)
593                 st->hand_state = TLS_ST_SW_SESSION_TICKET;
594             else
595                 st->hand_state = TLS_ST_SW_CHANGE;
596         } else {
597             /* Check if it is anon DH or anon ECDH, */
598             /* normal PSK or SRP */
599             if (!(s->s3->tmp.new_cipher->algorithm_auth &
600                   (SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
601                 st->hand_state = TLS_ST_SW_CERT;
602             } else if (send_server_key_exchange(s)) {
603                 st->hand_state = TLS_ST_SW_KEY_EXCH;
604             } else if (send_certificate_request(s)) {
605                 st->hand_state = TLS_ST_SW_CERT_REQ;
606             } else {
607                 st->hand_state = TLS_ST_SW_SRVR_DONE;
608             }
609         }
610         return WRITE_TRAN_CONTINUE;
611 
612     case TLS_ST_SW_CERT:
613         if (s->ext.status_expected) {
614             st->hand_state = TLS_ST_SW_CERT_STATUS;
615             return WRITE_TRAN_CONTINUE;
616         }
617         /* Fall through */
618 
619     case TLS_ST_SW_CERT_STATUS:
620         if (send_server_key_exchange(s)) {
621             st->hand_state = TLS_ST_SW_KEY_EXCH;
622             return WRITE_TRAN_CONTINUE;
623         }
624         /* Fall through */
625 
626     case TLS_ST_SW_KEY_EXCH:
627         if (send_certificate_request(s)) {
628             st->hand_state = TLS_ST_SW_CERT_REQ;
629             return WRITE_TRAN_CONTINUE;
630         }
631         /* Fall through */
632 
633     case TLS_ST_SW_CERT_REQ:
634         st->hand_state = TLS_ST_SW_SRVR_DONE;
635         return WRITE_TRAN_CONTINUE;
636 
637     case TLS_ST_SW_SRVR_DONE:
638         return WRITE_TRAN_FINISHED;
639 
640     case TLS_ST_SR_FINISHED:
641         if (s->hit) {
642             st->hand_state = TLS_ST_OK;
643             return WRITE_TRAN_CONTINUE;
644         } else if (s->ext.ticket_expected) {
645             st->hand_state = TLS_ST_SW_SESSION_TICKET;
646         } else {
647             st->hand_state = TLS_ST_SW_CHANGE;
648         }
649         return WRITE_TRAN_CONTINUE;
650 
651     case TLS_ST_SW_SESSION_TICKET:
652         st->hand_state = TLS_ST_SW_CHANGE;
653         return WRITE_TRAN_CONTINUE;
654 
655     case TLS_ST_SW_CHANGE:
656         st->hand_state = TLS_ST_SW_FINISHED;
657         return WRITE_TRAN_CONTINUE;
658 
659     case TLS_ST_SW_FINISHED:
660         if (s->hit) {
661             return WRITE_TRAN_FINISHED;
662         }
663         st->hand_state = TLS_ST_OK;
664         return WRITE_TRAN_CONTINUE;
665     }
666 }
667 
668 /*
669  * Perform any pre work that needs to be done prior to sending a message from
670  * the server to the client.
671  */
672 WORK_STATE ossl_statem_server_pre_work(SSL *s, WORK_STATE wst)
673 {
674     OSSL_STATEM *st = &s->statem;
675 
676     switch (st->hand_state) {
677     default:
678         /* No pre work to be done */
679         break;
680 
681     case TLS_ST_SW_HELLO_REQ:
682         s->shutdown = 0;
683         if (SSL_IS_DTLS(s))
684             dtls1_clear_sent_buffer(s);
685         break;
686 
687     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
688         s->shutdown = 0;
689         if (SSL_IS_DTLS(s)) {
690             dtls1_clear_sent_buffer(s);
691             /* We don't buffer this message so don't use the timer */
692             st->use_timer = 0;
693         }
694         break;
695 
696     case TLS_ST_SW_SRVR_HELLO:
697         if (SSL_IS_DTLS(s)) {
698             /*
699              * Messages we write from now on should be buffered and
700              * retransmitted if necessary, so we need to use the timer now
701              */
702             st->use_timer = 1;
703         }
704         break;
705 
706     case TLS_ST_SW_SRVR_DONE:
707 #ifndef OPENSSL_NO_SCTP
708         if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
709             /* Calls SSLfatal() as required */
710             return dtls_wait_for_dry(s);
711         }
712 #endif
713         return WORK_FINISHED_CONTINUE;
714 
715     case TLS_ST_SW_SESSION_TICKET:
716         if (SSL_IS_TLS13(s) && s->sent_tickets == 0) {
717             /*
718              * Actually this is the end of the handshake, but we're going
719              * straight into writing the session ticket out. So we finish off
720              * the handshake, but keep the various buffers active.
721              *
722              * Calls SSLfatal as required.
723              */
724             return tls_finish_handshake(s, wst, 0, 0);
725         } if (SSL_IS_DTLS(s)) {
726             /*
727              * We're into the last flight. We don't retransmit the last flight
728              * unless we need to, so we don't use the timer
729              */
730             st->use_timer = 0;
731         }
732         break;
733 
734     case TLS_ST_SW_CHANGE:
735         if (SSL_IS_TLS13(s))
736             break;
737         s->session->cipher = s->s3->tmp.new_cipher;
738         if (!s->method->ssl3_enc->setup_key_block(s)) {
739             /* SSLfatal() already called */
740             return WORK_ERROR;
741         }
742         if (SSL_IS_DTLS(s)) {
743             /*
744              * We're into the last flight. We don't retransmit the last flight
745              * unless we need to, so we don't use the timer. This might have
746              * already been set to 0 if we sent a NewSessionTicket message,
747              * but we'll set it again here in case we didn't.
748              */
749             st->use_timer = 0;
750         }
751         return WORK_FINISHED_CONTINUE;
752 
753     case TLS_ST_EARLY_DATA:
754         if (s->early_data_state != SSL_EARLY_DATA_ACCEPTING
755                 && (s->s3->flags & TLS1_FLAGS_STATELESS) == 0)
756             return WORK_FINISHED_CONTINUE;
757         /* Fall through */
758 
759     case TLS_ST_OK:
760         /* Calls SSLfatal() as required */
761         return tls_finish_handshake(s, wst, 1, 1);
762     }
763 
764     return WORK_FINISHED_CONTINUE;
765 }
766 
767 static ossl_inline int conn_is_closed(void)
768 {
769     switch (get_last_sys_error()) {
770 #if defined(EPIPE)
771     case EPIPE:
772         return 1;
773 #endif
774 #if defined(ECONNRESET)
775     case ECONNRESET:
776         return 1;
777 #endif
778     default:
779         return 0;
780     }
781 }
782 
783 /*
784  * Perform any work that needs to be done after sending a message from the
785  * server to the client.
786  */
787 WORK_STATE ossl_statem_server_post_work(SSL *s, WORK_STATE wst)
788 {
789     OSSL_STATEM *st = &s->statem;
790 
791     s->init_num = 0;
792 
793     switch (st->hand_state) {
794     default:
795         /* No post work to be done */
796         break;
797 
798     case TLS_ST_SW_HELLO_REQ:
799         if (statem_flush(s) != 1)
800             return WORK_MORE_A;
801         if (!ssl3_init_finished_mac(s)) {
802             /* SSLfatal() already called */
803             return WORK_ERROR;
804         }
805         break;
806 
807     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
808         if (statem_flush(s) != 1)
809             return WORK_MORE_A;
810         /* HelloVerifyRequest resets Finished MAC */
811         if (s->version != DTLS1_BAD_VER && !ssl3_init_finished_mac(s)) {
812             /* SSLfatal() already called */
813             return WORK_ERROR;
814         }
815         /*
816          * The next message should be another ClientHello which we need to
817          * treat like it was the first packet
818          */
819         s->first_packet = 1;
820         break;
821 
822     case TLS_ST_SW_SRVR_HELLO:
823         if (SSL_IS_TLS13(s) && s->hello_retry_request == SSL_HRR_PENDING) {
824             if ((s->options & SSL_OP_ENABLE_MIDDLEBOX_COMPAT) == 0
825                     && statem_flush(s) != 1)
826                 return WORK_MORE_A;
827             break;
828         }
829 #ifndef OPENSSL_NO_SCTP
830         if (SSL_IS_DTLS(s) && s->hit) {
831             unsigned char sctpauthkey[64];
832             char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
833 
834             /*
835              * Add new shared key for SCTP-Auth, will be ignored if no
836              * SCTP used.
837              */
838             memcpy(labelbuffer, DTLS1_SCTP_AUTH_LABEL,
839                    sizeof(DTLS1_SCTP_AUTH_LABEL));
840 
841             if (SSL_export_keying_material(s, sctpauthkey,
842                                            sizeof(sctpauthkey), labelbuffer,
843                                            sizeof(labelbuffer), NULL, 0,
844                                            0) <= 0) {
845                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
846                          SSL_F_OSSL_STATEM_SERVER_POST_WORK,
847                          ERR_R_INTERNAL_ERROR);
848                 return WORK_ERROR;
849             }
850 
851             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
852                      sizeof(sctpauthkey), sctpauthkey);
853         }
854 #endif
855         if (!SSL_IS_TLS13(s)
856                 || ((s->options & SSL_OP_ENABLE_MIDDLEBOX_COMPAT) != 0
857                     && s->hello_retry_request != SSL_HRR_COMPLETE))
858             break;
859         /* Fall through */
860 
861     case TLS_ST_SW_CHANGE:
862         if (s->hello_retry_request == SSL_HRR_PENDING) {
863             if (!statem_flush(s))
864                 return WORK_MORE_A;
865             break;
866         }
867 
868         if (SSL_IS_TLS13(s)) {
869             if (!s->method->ssl3_enc->setup_key_block(s)
870                 || !s->method->ssl3_enc->change_cipher_state(s,
871                         SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
872                 /* SSLfatal() already called */
873                 return WORK_ERROR;
874             }
875 
876             if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED
877                 && !s->method->ssl3_enc->change_cipher_state(s,
878                         SSL3_CC_HANDSHAKE |SSL3_CHANGE_CIPHER_SERVER_READ)) {
879                 /* SSLfatal() already called */
880                 return WORK_ERROR;
881             }
882             /*
883              * We don't yet know whether the next record we are going to receive
884              * is an unencrypted alert, an encrypted alert, or an encrypted
885              * handshake message. We temporarily tolerate unencrypted alerts.
886              */
887             s->statem.enc_read_state = ENC_READ_STATE_ALLOW_PLAIN_ALERTS;
888             break;
889         }
890 
891 #ifndef OPENSSL_NO_SCTP
892         if (SSL_IS_DTLS(s) && !s->hit) {
893             /*
894              * Change to new shared key of SCTP-Auth, will be ignored if
895              * no SCTP used.
896              */
897             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
898                      0, NULL);
899         }
900 #endif
901         if (!s->method->ssl3_enc->change_cipher_state(s,
902                                                       SSL3_CHANGE_CIPHER_SERVER_WRITE))
903         {
904             /* SSLfatal() already called */
905             return WORK_ERROR;
906         }
907 
908         if (SSL_IS_DTLS(s))
909             dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
910         break;
911 
912     case TLS_ST_SW_SRVR_DONE:
913         if (statem_flush(s) != 1)
914             return WORK_MORE_A;
915         break;
916 
917     case TLS_ST_SW_FINISHED:
918         if (statem_flush(s) != 1)
919             return WORK_MORE_A;
920 #ifndef OPENSSL_NO_SCTP
921         if (SSL_IS_DTLS(s) && s->hit) {
922             /*
923              * Change to new shared key of SCTP-Auth, will be ignored if
924              * no SCTP used.
925              */
926             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
927                      0, NULL);
928         }
929 #endif
930         if (SSL_IS_TLS13(s)) {
931             if (!s->method->ssl3_enc->generate_master_secret(s,
932                         s->master_secret, s->handshake_secret, 0,
933                         &s->session->master_key_length)
934                 || !s->method->ssl3_enc->change_cipher_state(s,
935                         SSL3_CC_APPLICATION | SSL3_CHANGE_CIPHER_SERVER_WRITE))
936             /* SSLfatal() already called */
937             return WORK_ERROR;
938         }
939         break;
940 
941     case TLS_ST_SW_CERT_REQ:
942         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
943             if (statem_flush(s) != 1)
944                 return WORK_MORE_A;
945         }
946         break;
947 
948     case TLS_ST_SW_KEY_UPDATE:
949         if (statem_flush(s) != 1)
950             return WORK_MORE_A;
951         if (!tls13_update_key(s, 1)) {
952             /* SSLfatal() already called */
953             return WORK_ERROR;
954         }
955         break;
956 
957     case TLS_ST_SW_SESSION_TICKET:
958         clear_sys_error();
959         if (SSL_IS_TLS13(s) && statem_flush(s) != 1) {
960             if (SSL_get_error(s, 0) == SSL_ERROR_SYSCALL
961                     && conn_is_closed()) {
962                 /*
963                  * We ignore connection closed errors in TLSv1.3 when sending a
964                  * NewSessionTicket and behave as if we were successful. This is
965                  * so that we are still able to read data sent to us by a client
966                  * that closes soon after the end of the handshake without
967                  * waiting to read our post-handshake NewSessionTickets.
968                  */
969                 s->rwstate = SSL_NOTHING;
970                 break;
971             }
972 
973             return WORK_MORE_A;
974         }
975         break;
976     }
977 
978     return WORK_FINISHED_CONTINUE;
979 }
980 
981 /*
982  * Get the message construction function and message type for sending from the
983  * server
984  *
985  * Valid return values are:
986  *   1: Success
987  *   0: Error
988  */
989 int ossl_statem_server_construct_message(SSL *s, WPACKET *pkt,
990                                          confunc_f *confunc, int *mt)
991 {
992     OSSL_STATEM *st = &s->statem;
993 
994     switch (st->hand_state) {
995     default:
996         /* Shouldn't happen */
997         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
998                  SSL_F_OSSL_STATEM_SERVER_CONSTRUCT_MESSAGE,
999                  SSL_R_BAD_HANDSHAKE_STATE);
1000         return 0;
1001 
1002     case TLS_ST_SW_CHANGE:
1003         if (SSL_IS_DTLS(s))
1004             *confunc = dtls_construct_change_cipher_spec;
1005         else
1006             *confunc = tls_construct_change_cipher_spec;
1007         *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
1008         break;
1009 
1010     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
1011         *confunc = dtls_construct_hello_verify_request;
1012         *mt = DTLS1_MT_HELLO_VERIFY_REQUEST;
1013         break;
1014 
1015     case TLS_ST_SW_HELLO_REQ:
1016         /* No construction function needed */
1017         *confunc = NULL;
1018         *mt = SSL3_MT_HELLO_REQUEST;
1019         break;
1020 
1021     case TLS_ST_SW_SRVR_HELLO:
1022         *confunc = tls_construct_server_hello;
1023         *mt = SSL3_MT_SERVER_HELLO;
1024         break;
1025 
1026     case TLS_ST_SW_CERT:
1027         *confunc = tls_construct_server_certificate;
1028         *mt = SSL3_MT_CERTIFICATE;
1029         break;
1030 
1031     case TLS_ST_SW_CERT_VRFY:
1032         *confunc = tls_construct_cert_verify;
1033         *mt = SSL3_MT_CERTIFICATE_VERIFY;
1034         break;
1035 
1036 
1037     case TLS_ST_SW_KEY_EXCH:
1038         *confunc = tls_construct_server_key_exchange;
1039         *mt = SSL3_MT_SERVER_KEY_EXCHANGE;
1040         break;
1041 
1042     case TLS_ST_SW_CERT_REQ:
1043         *confunc = tls_construct_certificate_request;
1044         *mt = SSL3_MT_CERTIFICATE_REQUEST;
1045         break;
1046 
1047     case TLS_ST_SW_SRVR_DONE:
1048         *confunc = tls_construct_server_done;
1049         *mt = SSL3_MT_SERVER_DONE;
1050         break;
1051 
1052     case TLS_ST_SW_SESSION_TICKET:
1053         *confunc = tls_construct_new_session_ticket;
1054         *mt = SSL3_MT_NEWSESSION_TICKET;
1055         break;
1056 
1057     case TLS_ST_SW_CERT_STATUS:
1058         *confunc = tls_construct_cert_status;
1059         *mt = SSL3_MT_CERTIFICATE_STATUS;
1060         break;
1061 
1062     case TLS_ST_SW_FINISHED:
1063         *confunc = tls_construct_finished;
1064         *mt = SSL3_MT_FINISHED;
1065         break;
1066 
1067     case TLS_ST_EARLY_DATA:
1068         *confunc = NULL;
1069         *mt = SSL3_MT_DUMMY;
1070         break;
1071 
1072     case TLS_ST_SW_ENCRYPTED_EXTENSIONS:
1073         *confunc = tls_construct_encrypted_extensions;
1074         *mt = SSL3_MT_ENCRYPTED_EXTENSIONS;
1075         break;
1076 
1077     case TLS_ST_SW_KEY_UPDATE:
1078         *confunc = tls_construct_key_update;
1079         *mt = SSL3_MT_KEY_UPDATE;
1080         break;
1081     }
1082 
1083     return 1;
1084 }
1085 
1086 /*
1087  * Maximum size (excluding the Handshake header) of a ClientHello message,
1088  * calculated as follows:
1089  *
1090  *  2 + # client_version
1091  *  32 + # only valid length for random
1092  *  1 + # length of session_id
1093  *  32 + # maximum size for session_id
1094  *  2 + # length of cipher suites
1095  *  2^16-2 + # maximum length of cipher suites array
1096  *  1 + # length of compression_methods
1097  *  2^8-1 + # maximum length of compression methods
1098  *  2 + # length of extensions
1099  *  2^16-1 # maximum length of extensions
1100  */
1101 #define CLIENT_HELLO_MAX_LENGTH         131396
1102 
1103 #define CLIENT_KEY_EXCH_MAX_LENGTH      2048
1104 #define NEXT_PROTO_MAX_LENGTH           514
1105 
1106 /*
1107  * Returns the maximum allowed length for the current message that we are
1108  * reading. Excludes the message header.
1109  */
1110 size_t ossl_statem_server_max_message_size(SSL *s)
1111 {
1112     OSSL_STATEM *st = &s->statem;
1113 
1114     switch (st->hand_state) {
1115     default:
1116         /* Shouldn't happen */
1117         return 0;
1118 
1119     case TLS_ST_SR_CLNT_HELLO:
1120         return CLIENT_HELLO_MAX_LENGTH;
1121 
1122     case TLS_ST_SR_END_OF_EARLY_DATA:
1123         return END_OF_EARLY_DATA_MAX_LENGTH;
1124 
1125     case TLS_ST_SR_CERT:
1126         return s->max_cert_list;
1127 
1128     case TLS_ST_SR_KEY_EXCH:
1129         return CLIENT_KEY_EXCH_MAX_LENGTH;
1130 
1131     case TLS_ST_SR_CERT_VRFY:
1132         return SSL3_RT_MAX_PLAIN_LENGTH;
1133 
1134 #ifndef OPENSSL_NO_NEXTPROTONEG
1135     case TLS_ST_SR_NEXT_PROTO:
1136         return NEXT_PROTO_MAX_LENGTH;
1137 #endif
1138 
1139     case TLS_ST_SR_CHANGE:
1140         return CCS_MAX_LENGTH;
1141 
1142     case TLS_ST_SR_FINISHED:
1143         return FINISHED_MAX_LENGTH;
1144 
1145     case TLS_ST_SR_KEY_UPDATE:
1146         return KEY_UPDATE_MAX_LENGTH;
1147     }
1148 }
1149 
1150 /*
1151  * Process a message that the server has received from the client.
1152  */
1153 MSG_PROCESS_RETURN ossl_statem_server_process_message(SSL *s, PACKET *pkt)
1154 {
1155     OSSL_STATEM *st = &s->statem;
1156 
1157     switch (st->hand_state) {
1158     default:
1159         /* Shouldn't happen */
1160         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1161                  SSL_F_OSSL_STATEM_SERVER_PROCESS_MESSAGE,
1162                  ERR_R_INTERNAL_ERROR);
1163         return MSG_PROCESS_ERROR;
1164 
1165     case TLS_ST_SR_CLNT_HELLO:
1166         return tls_process_client_hello(s, pkt);
1167 
1168     case TLS_ST_SR_END_OF_EARLY_DATA:
1169         return tls_process_end_of_early_data(s, pkt);
1170 
1171     case TLS_ST_SR_CERT:
1172         return tls_process_client_certificate(s, pkt);
1173 
1174     case TLS_ST_SR_KEY_EXCH:
1175         return tls_process_client_key_exchange(s, pkt);
1176 
1177     case TLS_ST_SR_CERT_VRFY:
1178         return tls_process_cert_verify(s, pkt);
1179 
1180 #ifndef OPENSSL_NO_NEXTPROTONEG
1181     case TLS_ST_SR_NEXT_PROTO:
1182         return tls_process_next_proto(s, pkt);
1183 #endif
1184 
1185     case TLS_ST_SR_CHANGE:
1186         return tls_process_change_cipher_spec(s, pkt);
1187 
1188     case TLS_ST_SR_FINISHED:
1189         return tls_process_finished(s, pkt);
1190 
1191     case TLS_ST_SR_KEY_UPDATE:
1192         return tls_process_key_update(s, pkt);
1193 
1194     }
1195 }
1196 
1197 /*
1198  * Perform any further processing required following the receipt of a message
1199  * from the client
1200  */
1201 WORK_STATE ossl_statem_server_post_process_message(SSL *s, WORK_STATE wst)
1202 {
1203     OSSL_STATEM *st = &s->statem;
1204 
1205     switch (st->hand_state) {
1206     default:
1207         /* Shouldn't happen */
1208         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1209                  SSL_F_OSSL_STATEM_SERVER_POST_PROCESS_MESSAGE,
1210                  ERR_R_INTERNAL_ERROR);
1211         return WORK_ERROR;
1212 
1213     case TLS_ST_SR_CLNT_HELLO:
1214         return tls_post_process_client_hello(s, wst);
1215 
1216     case TLS_ST_SR_KEY_EXCH:
1217         return tls_post_process_client_key_exchange(s, wst);
1218     }
1219 }
1220 
1221 #ifndef OPENSSL_NO_SRP
1222 /* Returns 1 on success, 0 for retryable error, -1 for fatal error */
1223 static int ssl_check_srp_ext_ClientHello(SSL *s)
1224 {
1225     int ret;
1226     int al = SSL_AD_UNRECOGNIZED_NAME;
1227 
1228     if ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_kSRP) &&
1229         (s->srp_ctx.TLS_ext_srp_username_callback != NULL)) {
1230         if (s->srp_ctx.login == NULL) {
1231             /*
1232              * RFC 5054 says SHOULD reject, we do so if There is no srp
1233              * login name
1234              */
1235             SSLfatal(s, SSL_AD_UNKNOWN_PSK_IDENTITY,
1236                      SSL_F_SSL_CHECK_SRP_EXT_CLIENTHELLO,
1237                      SSL_R_PSK_IDENTITY_NOT_FOUND);
1238             return -1;
1239         } else {
1240             ret = SSL_srp_server_param_with_username(s, &al);
1241             if (ret < 0)
1242                 return 0;
1243             if (ret == SSL3_AL_FATAL) {
1244                 SSLfatal(s, al, SSL_F_SSL_CHECK_SRP_EXT_CLIENTHELLO,
1245                          al == SSL_AD_UNKNOWN_PSK_IDENTITY
1246                          ? SSL_R_PSK_IDENTITY_NOT_FOUND
1247                          : SSL_R_CLIENTHELLO_TLSEXT);
1248                 return -1;
1249             }
1250         }
1251     }
1252     return 1;
1253 }
1254 #endif
1255 
1256 int dtls_raw_hello_verify_request(WPACKET *pkt, unsigned char *cookie,
1257                                   size_t cookie_len)
1258 {
1259     /* Always use DTLS 1.0 version: see RFC 6347 */
1260     if (!WPACKET_put_bytes_u16(pkt, DTLS1_VERSION)
1261             || !WPACKET_sub_memcpy_u8(pkt, cookie, cookie_len))
1262         return 0;
1263 
1264     return 1;
1265 }
1266 
1267 int dtls_construct_hello_verify_request(SSL *s, WPACKET *pkt)
1268 {
1269     unsigned int cookie_leni;
1270     if (s->ctx->app_gen_cookie_cb == NULL ||
1271         s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
1272                                   &cookie_leni) == 0 ||
1273         cookie_leni > 255) {
1274         SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST,
1275                  SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
1276         return 0;
1277     }
1278     s->d1->cookie_len = cookie_leni;
1279 
1280     if (!dtls_raw_hello_verify_request(pkt, s->d1->cookie,
1281                                               s->d1->cookie_len)) {
1282         SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST,
1283                  ERR_R_INTERNAL_ERROR);
1284         return 0;
1285     }
1286 
1287     return 1;
1288 }
1289 
1290 #ifndef OPENSSL_NO_EC
1291 /*-
1292  * ssl_check_for_safari attempts to fingerprint Safari using OS X
1293  * SecureTransport using the TLS extension block in |hello|.
1294  * Safari, since 10.6, sends exactly these extensions, in this order:
1295  *   SNI,
1296  *   elliptic_curves
1297  *   ec_point_formats
1298  *   signature_algorithms (for TLSv1.2 only)
1299  *
1300  * We wish to fingerprint Safari because they broke ECDHE-ECDSA support in 10.8,
1301  * but they advertise support. So enabling ECDHE-ECDSA ciphers breaks them.
1302  * Sadly we cannot differentiate 10.6, 10.7 and 10.8.4 (which work), from
1303  * 10.8..10.8.3 (which don't work).
1304  */
1305 static void ssl_check_for_safari(SSL *s, const CLIENTHELLO_MSG *hello)
1306 {
1307     static const unsigned char kSafariExtensionsBlock[] = {
1308         0x00, 0x0a,             /* elliptic_curves extension */
1309         0x00, 0x08,             /* 8 bytes */
1310         0x00, 0x06,             /* 6 bytes of curve ids */
1311         0x00, 0x17,             /* P-256 */
1312         0x00, 0x18,             /* P-384 */
1313         0x00, 0x19,             /* P-521 */
1314 
1315         0x00, 0x0b,             /* ec_point_formats */
1316         0x00, 0x02,             /* 2 bytes */
1317         0x01,                   /* 1 point format */
1318         0x00,                   /* uncompressed */
1319         /* The following is only present in TLS 1.2 */
1320         0x00, 0x0d,             /* signature_algorithms */
1321         0x00, 0x0c,             /* 12 bytes */
1322         0x00, 0x0a,             /* 10 bytes */
1323         0x05, 0x01,             /* SHA-384/RSA */
1324         0x04, 0x01,             /* SHA-256/RSA */
1325         0x02, 0x01,             /* SHA-1/RSA */
1326         0x04, 0x03,             /* SHA-256/ECDSA */
1327         0x02, 0x03,             /* SHA-1/ECDSA */
1328     };
1329     /* Length of the common prefix (first two extensions). */
1330     static const size_t kSafariCommonExtensionsLength = 18;
1331     unsigned int type;
1332     PACKET sni, tmppkt;
1333     size_t ext_len;
1334 
1335     tmppkt = hello->extensions;
1336 
1337     if (!PACKET_forward(&tmppkt, 2)
1338         || !PACKET_get_net_2(&tmppkt, &type)
1339         || !PACKET_get_length_prefixed_2(&tmppkt, &sni)) {
1340         return;
1341     }
1342 
1343     if (type != TLSEXT_TYPE_server_name)
1344         return;
1345 
1346     ext_len = TLS1_get_client_version(s) >= TLS1_2_VERSION ?
1347         sizeof(kSafariExtensionsBlock) : kSafariCommonExtensionsLength;
1348 
1349     s->s3->is_probably_safari = PACKET_equal(&tmppkt, kSafariExtensionsBlock,
1350                                              ext_len);
1351 }
1352 #endif                          /* !OPENSSL_NO_EC */
1353 
1354 MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
1355 {
1356     /* |cookie| will only be initialized for DTLS. */
1357     PACKET session_id, compression, extensions, cookie;
1358     static const unsigned char null_compression = 0;
1359     CLIENTHELLO_MSG *clienthello = NULL;
1360 
1361     /* Check if this is actually an unexpected renegotiation ClientHello */
1362     if (s->renegotiate == 0 && !SSL_IS_FIRST_HANDSHAKE(s)) {
1363         if (!ossl_assert(!SSL_IS_TLS13(s))) {
1364             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1365                      ERR_R_INTERNAL_ERROR);
1366             goto err;
1367         }
1368         if ((s->options & SSL_OP_NO_RENEGOTIATION) != 0
1369                 || (!s->s3->send_connection_binding
1370                     && (s->options
1371                         & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) == 0)) {
1372             ssl3_send_alert(s, SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
1373             return MSG_PROCESS_FINISHED_READING;
1374         }
1375         s->renegotiate = 1;
1376         s->new_session = 1;
1377     }
1378 
1379     clienthello = OPENSSL_zalloc(sizeof(*clienthello));
1380     if (clienthello == NULL) {
1381         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1382                  ERR_R_INTERNAL_ERROR);
1383         goto err;
1384     }
1385 
1386     /*
1387      * First, parse the raw ClientHello data into the CLIENTHELLO_MSG structure.
1388      */
1389     clienthello->isv2 = RECORD_LAYER_is_sslv2_record(&s->rlayer);
1390     PACKET_null_init(&cookie);
1391 
1392     if (clienthello->isv2) {
1393         unsigned int mt;
1394 
1395         if (!SSL_IS_FIRST_HANDSHAKE(s)
1396                 || s->hello_retry_request != SSL_HRR_NONE) {
1397             SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
1398                      SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_UNEXPECTED_MESSAGE);
1399             goto err;
1400         }
1401 
1402         /*-
1403          * An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2
1404          * header is sent directly on the wire, not wrapped as a TLS
1405          * record. Our record layer just processes the message length and passes
1406          * the rest right through. Its format is:
1407          * Byte  Content
1408          * 0-1   msg_length - decoded by the record layer
1409          * 2     msg_type - s->init_msg points here
1410          * 3-4   version
1411          * 5-6   cipher_spec_length
1412          * 7-8   session_id_length
1413          * 9-10  challenge_length
1414          * ...   ...
1415          */
1416 
1417         if (!PACKET_get_1(pkt, &mt)
1418             || mt != SSL2_MT_CLIENT_HELLO) {
1419             /*
1420              * Should never happen. We should have tested this in the record
1421              * layer in order to have determined that this is a SSLv2 record
1422              * in the first place
1423              */
1424             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1425                      ERR_R_INTERNAL_ERROR);
1426             goto err;
1427         }
1428     }
1429 
1430     if (!PACKET_get_net_2(pkt, &clienthello->legacy_version)) {
1431         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1432                  SSL_R_LENGTH_TOO_SHORT);
1433         goto err;
1434     }
1435 
1436     /* Parse the message and load client random. */
1437     if (clienthello->isv2) {
1438         /*
1439          * Handle an SSLv2 backwards compatible ClientHello
1440          * Note, this is only for SSLv3+ using the backward compatible format.
1441          * Real SSLv2 is not supported, and is rejected below.
1442          */
1443         unsigned int ciphersuite_len, session_id_len, challenge_len;
1444         PACKET challenge;
1445 
1446         if (!PACKET_get_net_2(pkt, &ciphersuite_len)
1447             || !PACKET_get_net_2(pkt, &session_id_len)
1448             || !PACKET_get_net_2(pkt, &challenge_len)) {
1449             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1450                      SSL_R_RECORD_LENGTH_MISMATCH);
1451             goto err;
1452         }
1453 
1454         if (session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
1455             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1456                      SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
1457             goto err;
1458         }
1459 
1460         if (!PACKET_get_sub_packet(pkt, &clienthello->ciphersuites,
1461                                    ciphersuite_len)
1462             || !PACKET_copy_bytes(pkt, clienthello->session_id, session_id_len)
1463             || !PACKET_get_sub_packet(pkt, &challenge, challenge_len)
1464             /* No extensions. */
1465             || PACKET_remaining(pkt) != 0) {
1466             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1467                      SSL_R_RECORD_LENGTH_MISMATCH);
1468             goto err;
1469         }
1470         clienthello->session_id_len = session_id_len;
1471 
1472         /* Load the client random and compression list. We use SSL3_RANDOM_SIZE
1473          * here rather than sizeof(clienthello->random) because that is the limit
1474          * for SSLv3 and it is fixed. It won't change even if
1475          * sizeof(clienthello->random) does.
1476          */
1477         challenge_len = challenge_len > SSL3_RANDOM_SIZE
1478                         ? SSL3_RANDOM_SIZE : challenge_len;
1479         memset(clienthello->random, 0, SSL3_RANDOM_SIZE);
1480         if (!PACKET_copy_bytes(&challenge,
1481                                clienthello->random + SSL3_RANDOM_SIZE -
1482                                challenge_len, challenge_len)
1483             /* Advertise only null compression. */
1484             || !PACKET_buf_init(&compression, &null_compression, 1)) {
1485             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1486                      ERR_R_INTERNAL_ERROR);
1487             goto err;
1488         }
1489 
1490         PACKET_null_init(&clienthello->extensions);
1491     } else {
1492         /* Regular ClientHello. */
1493         if (!PACKET_copy_bytes(pkt, clienthello->random, SSL3_RANDOM_SIZE)
1494             || !PACKET_get_length_prefixed_1(pkt, &session_id)
1495             || !PACKET_copy_all(&session_id, clienthello->session_id,
1496                     SSL_MAX_SSL_SESSION_ID_LENGTH,
1497                     &clienthello->session_id_len)) {
1498             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1499                      SSL_R_LENGTH_MISMATCH);
1500             goto err;
1501         }
1502 
1503         if (SSL_IS_DTLS(s)) {
1504             if (!PACKET_get_length_prefixed_1(pkt, &cookie)) {
1505                 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1506                          SSL_R_LENGTH_MISMATCH);
1507                 goto err;
1508             }
1509             if (!PACKET_copy_all(&cookie, clienthello->dtls_cookie,
1510                                  DTLS1_COOKIE_LENGTH,
1511                                  &clienthello->dtls_cookie_len)) {
1512                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1513                          SSL_F_TLS_PROCESS_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
1514                 goto err;
1515             }
1516             /*
1517              * If we require cookies and this ClientHello doesn't contain one,
1518              * just return since we do not want to allocate any memory yet.
1519              * So check cookie length...
1520              */
1521             if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
1522                 if (clienthello->dtls_cookie_len == 0)
1523                     return MSG_PROCESS_FINISHED_READING;
1524             }
1525         }
1526 
1527         if (!PACKET_get_length_prefixed_2(pkt, &clienthello->ciphersuites)) {
1528             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1529                      SSL_R_LENGTH_MISMATCH);
1530             goto err;
1531         }
1532 
1533         if (!PACKET_get_length_prefixed_1(pkt, &compression)) {
1534             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1535                      SSL_R_LENGTH_MISMATCH);
1536             goto err;
1537         }
1538 
1539         /* Could be empty. */
1540         if (PACKET_remaining(pkt) == 0) {
1541             PACKET_null_init(&clienthello->extensions);
1542         } else {
1543             if (!PACKET_get_length_prefixed_2(pkt, &clienthello->extensions)
1544                     || PACKET_remaining(pkt) != 0) {
1545                 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1546                          SSL_R_LENGTH_MISMATCH);
1547                 goto err;
1548             }
1549         }
1550     }
1551 
1552     if (!PACKET_copy_all(&compression, clienthello->compressions,
1553                          MAX_COMPRESSIONS_SIZE,
1554                          &clienthello->compressions_len)) {
1555         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1556                  ERR_R_INTERNAL_ERROR);
1557         goto err;
1558     }
1559 
1560     /* Preserve the raw extensions PACKET for later use */
1561     extensions = clienthello->extensions;
1562     if (!tls_collect_extensions(s, &extensions, SSL_EXT_CLIENT_HELLO,
1563                                 &clienthello->pre_proc_exts,
1564                                 &clienthello->pre_proc_exts_len, 1)) {
1565         /* SSLfatal already been called */
1566         goto err;
1567     }
1568     s->clienthello = clienthello;
1569 
1570     return MSG_PROCESS_CONTINUE_PROCESSING;
1571 
1572  err:
1573     if (clienthello != NULL)
1574         OPENSSL_free(clienthello->pre_proc_exts);
1575     OPENSSL_free(clienthello);
1576 
1577     return MSG_PROCESS_ERROR;
1578 }
1579 
1580 static int tls_early_post_process_client_hello(SSL *s)
1581 {
1582     unsigned int j;
1583     int i, al = SSL_AD_INTERNAL_ERROR;
1584     int protverr;
1585     size_t loop;
1586     unsigned long id;
1587 #ifndef OPENSSL_NO_COMP
1588     SSL_COMP *comp = NULL;
1589 #endif
1590     const SSL_CIPHER *c;
1591     STACK_OF(SSL_CIPHER) *ciphers = NULL;
1592     STACK_OF(SSL_CIPHER) *scsvs = NULL;
1593     CLIENTHELLO_MSG *clienthello = s->clienthello;
1594     DOWNGRADE dgrd = DOWNGRADE_NONE;
1595 
1596     /* Finished parsing the ClientHello, now we can start processing it */
1597     /* Give the ClientHello callback a crack at things */
1598     if (s->ctx->client_hello_cb != NULL) {
1599         /* A failure in the ClientHello callback terminates the connection. */
1600         switch (s->ctx->client_hello_cb(s, &al, s->ctx->client_hello_cb_arg)) {
1601         case SSL_CLIENT_HELLO_SUCCESS:
1602             break;
1603         case SSL_CLIENT_HELLO_RETRY:
1604             s->rwstate = SSL_CLIENT_HELLO_CB;
1605             return -1;
1606         case SSL_CLIENT_HELLO_ERROR:
1607         default:
1608             SSLfatal(s, al,
1609                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1610                      SSL_R_CALLBACK_FAILED);
1611             goto err;
1612         }
1613     }
1614 
1615     /* Set up the client_random */
1616     memcpy(s->s3->client_random, clienthello->random, SSL3_RANDOM_SIZE);
1617 
1618     /* Choose the version */
1619 
1620     if (clienthello->isv2) {
1621         if (clienthello->legacy_version == SSL2_VERSION
1622                 || (clienthello->legacy_version & 0xff00)
1623                    != (SSL3_VERSION_MAJOR << 8)) {
1624             /*
1625              * This is real SSLv2 or something completely unknown. We don't
1626              * support it.
1627              */
1628             SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
1629                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1630                      SSL_R_UNKNOWN_PROTOCOL);
1631             goto err;
1632         }
1633         /* SSLv3/TLS */
1634         s->client_version = clienthello->legacy_version;
1635     }
1636     /*
1637      * Do SSL/TLS version negotiation if applicable. For DTLS we just check
1638      * versions are potentially compatible. Version negotiation comes later.
1639      */
1640     if (!SSL_IS_DTLS(s)) {
1641         protverr = ssl_choose_server_version(s, clienthello, &dgrd);
1642     } else if (s->method->version != DTLS_ANY_VERSION &&
1643                DTLS_VERSION_LT((int)clienthello->legacy_version, s->version)) {
1644         protverr = SSL_R_VERSION_TOO_LOW;
1645     } else {
1646         protverr = 0;
1647     }
1648 
1649     if (protverr) {
1650         if (SSL_IS_FIRST_HANDSHAKE(s)) {
1651             /* like ssl3_get_record, send alert using remote version number */
1652             s->version = s->client_version = clienthello->legacy_version;
1653         }
1654         SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
1655                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO, protverr);
1656         goto err;
1657     }
1658 
1659     /* TLSv1.3 specifies that a ClientHello must end on a record boundary */
1660     if (SSL_IS_TLS13(s) && RECORD_LAYER_processed_read_pending(&s->rlayer)) {
1661         SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
1662                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1663                  SSL_R_NOT_ON_RECORD_BOUNDARY);
1664         goto err;
1665     }
1666 
1667     if (SSL_IS_DTLS(s)) {
1668         /* Empty cookie was already handled above by returning early. */
1669         if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
1670             if (s->ctx->app_verify_cookie_cb != NULL) {
1671                 if (s->ctx->app_verify_cookie_cb(s, clienthello->dtls_cookie,
1672                         clienthello->dtls_cookie_len) == 0) {
1673                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1674                              SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1675                              SSL_R_COOKIE_MISMATCH);
1676                     goto err;
1677                     /* else cookie verification succeeded */
1678                 }
1679                 /* default verification */
1680             } else if (s->d1->cookie_len != clienthello->dtls_cookie_len
1681                     || memcmp(clienthello->dtls_cookie, s->d1->cookie,
1682                               s->d1->cookie_len) != 0) {
1683                 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1684                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1685                          SSL_R_COOKIE_MISMATCH);
1686                 goto err;
1687             }
1688             s->d1->cookie_verified = 1;
1689         }
1690         if (s->method->version == DTLS_ANY_VERSION) {
1691             protverr = ssl_choose_server_version(s, clienthello, &dgrd);
1692             if (protverr != 0) {
1693                 s->version = s->client_version;
1694                 SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
1695                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO, protverr);
1696                 goto err;
1697             }
1698         }
1699     }
1700 
1701     s->hit = 0;
1702 
1703     if (!ssl_cache_cipherlist(s, &clienthello->ciphersuites,
1704                               clienthello->isv2) ||
1705         !bytes_to_cipher_list(s, &clienthello->ciphersuites, &ciphers, &scsvs,
1706                               clienthello->isv2, 1)) {
1707         /* SSLfatal() already called */
1708         goto err;
1709     }
1710 
1711     s->s3->send_connection_binding = 0;
1712     /* Check what signalling cipher-suite values were received. */
1713     if (scsvs != NULL) {
1714         for(i = 0; i < sk_SSL_CIPHER_num(scsvs); i++) {
1715             c = sk_SSL_CIPHER_value(scsvs, i);
1716             if (SSL_CIPHER_get_id(c) == SSL3_CK_SCSV) {
1717                 if (s->renegotiate) {
1718                     /* SCSV is fatal if renegotiating */
1719                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1720                              SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1721                              SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING);
1722                     goto err;
1723                 }
1724                 s->s3->send_connection_binding = 1;
1725             } else if (SSL_CIPHER_get_id(c) == SSL3_CK_FALLBACK_SCSV &&
1726                        !ssl_check_version_downgrade(s)) {
1727                 /*
1728                  * This SCSV indicates that the client previously tried
1729                  * a higher version.  We should fail if the current version
1730                  * is an unexpected downgrade, as that indicates that the first
1731                  * connection may have been tampered with in order to trigger
1732                  * an insecure downgrade.
1733                  */
1734                 SSLfatal(s, SSL_AD_INAPPROPRIATE_FALLBACK,
1735                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1736                          SSL_R_INAPPROPRIATE_FALLBACK);
1737                 goto err;
1738             }
1739         }
1740     }
1741 
1742     /* For TLSv1.3 we must select the ciphersuite *before* session resumption */
1743     if (SSL_IS_TLS13(s)) {
1744         const SSL_CIPHER *cipher =
1745             ssl3_choose_cipher(s, ciphers, SSL_get_ciphers(s));
1746 
1747         if (cipher == NULL) {
1748             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1749                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1750                      SSL_R_NO_SHARED_CIPHER);
1751             goto err;
1752         }
1753         if (s->hello_retry_request == SSL_HRR_PENDING
1754                 && (s->s3->tmp.new_cipher == NULL
1755                     || s->s3->tmp.new_cipher->id != cipher->id)) {
1756             /*
1757              * A previous HRR picked a different ciphersuite to the one we
1758              * just selected. Something must have changed.
1759              */
1760             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1761                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1762                      SSL_R_BAD_CIPHER);
1763             goto err;
1764         }
1765         s->s3->tmp.new_cipher = cipher;
1766     }
1767 
1768     /* We need to do this before getting the session */
1769     if (!tls_parse_extension(s, TLSEXT_IDX_extended_master_secret,
1770                              SSL_EXT_CLIENT_HELLO,
1771                              clienthello->pre_proc_exts, NULL, 0)) {
1772         /* SSLfatal() already called */
1773         goto err;
1774     }
1775 
1776     /*
1777      * We don't allow resumption in a backwards compatible ClientHello.
1778      * TODO(openssl-team): in TLS1.1+, session_id MUST be empty.
1779      *
1780      * Versions before 0.9.7 always allow clients to resume sessions in
1781      * renegotiation. 0.9.7 and later allow this by default, but optionally
1782      * ignore resumption requests with flag
1783      * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag rather
1784      * than a change to default behavior so that applications relying on
1785      * this for security won't even compile against older library versions).
1786      * 1.0.1 and later also have a function SSL_renegotiate_abbreviated() to
1787      * request renegotiation but not a new session (s->new_session remains
1788      * unset): for servers, this essentially just means that the
1789      * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
1790      * ignored.
1791      */
1792     if (clienthello->isv2 ||
1793         (s->new_session &&
1794          (s->options & SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
1795         if (!ssl_get_new_session(s, 1)) {
1796             /* SSLfatal() already called */
1797             goto err;
1798         }
1799     } else {
1800         i = ssl_get_prev_session(s, clienthello);
1801         if (i == 1) {
1802             /* previous session */
1803             s->hit = 1;
1804         } else if (i == -1) {
1805             /* SSLfatal() already called */
1806             goto err;
1807         } else {
1808             /* i == 0 */
1809             if (!ssl_get_new_session(s, 1)) {
1810                 /* SSLfatal() already called */
1811                 goto err;
1812             }
1813         }
1814     }
1815 
1816     if (SSL_IS_TLS13(s)) {
1817         memcpy(s->tmp_session_id, s->clienthello->session_id,
1818                s->clienthello->session_id_len);
1819         s->tmp_session_id_len = s->clienthello->session_id_len;
1820     }
1821 
1822     /*
1823      * If it is a hit, check that the cipher is in the list. In TLSv1.3 we check
1824      * ciphersuite compatibility with the session as part of resumption.
1825      */
1826     if (!SSL_IS_TLS13(s) && s->hit) {
1827         j = 0;
1828         id = s->session->cipher->id;
1829 
1830 #ifdef CIPHER_DEBUG
1831         fprintf(stderr, "client sent %d ciphers\n", sk_SSL_CIPHER_num(ciphers));
1832 #endif
1833         for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
1834             c = sk_SSL_CIPHER_value(ciphers, i);
1835 #ifdef CIPHER_DEBUG
1836             fprintf(stderr, "client [%2d of %2d]:%s\n",
1837                     i, sk_SSL_CIPHER_num(ciphers), SSL_CIPHER_get_name(c));
1838 #endif
1839             if (c->id == id) {
1840                 j = 1;
1841                 break;
1842             }
1843         }
1844         if (j == 0) {
1845             /*
1846              * we need to have the cipher in the cipher list if we are asked
1847              * to reuse it
1848              */
1849             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1850                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1851                      SSL_R_REQUIRED_CIPHER_MISSING);
1852             goto err;
1853         }
1854     }
1855 
1856     for (loop = 0; loop < clienthello->compressions_len; loop++) {
1857         if (clienthello->compressions[loop] == 0)
1858             break;
1859     }
1860 
1861     if (loop >= clienthello->compressions_len) {
1862         /* no compress */
1863         SSLfatal(s, SSL_AD_DECODE_ERROR,
1864                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1865                  SSL_R_NO_COMPRESSION_SPECIFIED);
1866         goto err;
1867     }
1868 
1869 #ifndef OPENSSL_NO_EC
1870     if (s->options & SSL_OP_SAFARI_ECDHE_ECDSA_BUG)
1871         ssl_check_for_safari(s, clienthello);
1872 #endif                          /* !OPENSSL_NO_EC */
1873 
1874     /* TLS extensions */
1875     if (!tls_parse_all_extensions(s, SSL_EXT_CLIENT_HELLO,
1876                                   clienthello->pre_proc_exts, NULL, 0, 1)) {
1877         /* SSLfatal() already called */
1878         goto err;
1879     }
1880 
1881     /*
1882      * Check if we want to use external pre-shared secret for this handshake
1883      * for not reused session only. We need to generate server_random before
1884      * calling tls_session_secret_cb in order to allow SessionTicket
1885      * processing to use it in key derivation.
1886      */
1887     {
1888         unsigned char *pos;
1889         pos = s->s3->server_random;
1890         if (ssl_fill_hello_random(s, 1, pos, SSL3_RANDOM_SIZE, dgrd) <= 0) {
1891             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1892                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1893                      ERR_R_INTERNAL_ERROR);
1894             goto err;
1895         }
1896     }
1897 
1898     if (!s->hit
1899             && s->version >= TLS1_VERSION
1900             && !SSL_IS_TLS13(s)
1901             && !SSL_IS_DTLS(s)
1902             && s->ext.session_secret_cb) {
1903         const SSL_CIPHER *pref_cipher = NULL;
1904         /*
1905          * s->session->master_key_length is a size_t, but this is an int for
1906          * backwards compat reasons
1907          */
1908         int master_key_length;
1909 
1910         master_key_length = sizeof(s->session->master_key);
1911         if (s->ext.session_secret_cb(s, s->session->master_key,
1912                                      &master_key_length, ciphers,
1913                                      &pref_cipher,
1914                                      s->ext.session_secret_cb_arg)
1915                 && master_key_length > 0) {
1916             s->session->master_key_length = master_key_length;
1917             s->hit = 1;
1918             s->session->ciphers = ciphers;
1919             s->session->verify_result = X509_V_OK;
1920 
1921             ciphers = NULL;
1922 
1923             /* check if some cipher was preferred by call back */
1924             if (pref_cipher == NULL)
1925                 pref_cipher = ssl3_choose_cipher(s, s->session->ciphers,
1926                                                  SSL_get_ciphers(s));
1927             if (pref_cipher == NULL) {
1928                 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1929                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1930                          SSL_R_NO_SHARED_CIPHER);
1931                 goto err;
1932             }
1933 
1934             s->session->cipher = pref_cipher;
1935             sk_SSL_CIPHER_free(s->cipher_list);
1936             s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
1937             sk_SSL_CIPHER_free(s->cipher_list_by_id);
1938             s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->session->ciphers);
1939         }
1940     }
1941 
1942     /*
1943      * Worst case, we will use the NULL compression, but if we have other
1944      * options, we will now look for them.  We have complen-1 compression
1945      * algorithms from the client, starting at q.
1946      */
1947     s->s3->tmp.new_compression = NULL;
1948     if (SSL_IS_TLS13(s)) {
1949         /*
1950          * We already checked above that the NULL compression method appears in
1951          * the list. Now we check there aren't any others (which is illegal in
1952          * a TLSv1.3 ClientHello.
1953          */
1954         if (clienthello->compressions_len != 1) {
1955             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1956                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1957                      SSL_R_INVALID_COMPRESSION_ALGORITHM);
1958             goto err;
1959         }
1960     }
1961 #ifndef OPENSSL_NO_COMP
1962     /* This only happens if we have a cache hit */
1963     else if (s->session->compress_meth != 0) {
1964         int m, comp_id = s->session->compress_meth;
1965         unsigned int k;
1966         /* Perform sanity checks on resumed compression algorithm */
1967         /* Can't disable compression */
1968         if (!ssl_allow_compression(s)) {
1969             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1970                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1971                      SSL_R_INCONSISTENT_COMPRESSION);
1972             goto err;
1973         }
1974         /* Look for resumed compression method */
1975         for (m = 0; m < sk_SSL_COMP_num(s->ctx->comp_methods); m++) {
1976             comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
1977             if (comp_id == comp->id) {
1978                 s->s3->tmp.new_compression = comp;
1979                 break;
1980             }
1981         }
1982         if (s->s3->tmp.new_compression == NULL) {
1983             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1984                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1985                      SSL_R_INVALID_COMPRESSION_ALGORITHM);
1986             goto err;
1987         }
1988         /* Look for resumed method in compression list */
1989         for (k = 0; k < clienthello->compressions_len; k++) {
1990             if (clienthello->compressions[k] == comp_id)
1991                 break;
1992         }
1993         if (k >= clienthello->compressions_len) {
1994             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1995                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1996                      SSL_R_REQUIRED_COMPRESSION_ALGORITHM_MISSING);
1997             goto err;
1998         }
1999     } else if (s->hit) {
2000         comp = NULL;
2001     } else if (ssl_allow_compression(s) && s->ctx->comp_methods) {
2002         /* See if we have a match */
2003         int m, nn, v, done = 0;
2004         unsigned int o;
2005 
2006         nn = sk_SSL_COMP_num(s->ctx->comp_methods);
2007         for (m = 0; m < nn; m++) {
2008             comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
2009             v = comp->id;
2010             for (o = 0; o < clienthello->compressions_len; o++) {
2011                 if (v == clienthello->compressions[o]) {
2012                     done = 1;
2013                     break;
2014                 }
2015             }
2016             if (done)
2017                 break;
2018         }
2019         if (done)
2020             s->s3->tmp.new_compression = comp;
2021         else
2022             comp = NULL;
2023     }
2024 #else
2025     /*
2026      * If compression is disabled we'd better not try to resume a session
2027      * using compression.
2028      */
2029     if (s->session->compress_meth != 0) {
2030         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2031                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2032                  SSL_R_INCONSISTENT_COMPRESSION);
2033         goto err;
2034     }
2035 #endif
2036 
2037     /*
2038      * Given s->session->ciphers and SSL_get_ciphers, we must pick a cipher
2039      */
2040 
2041     if (!s->hit || SSL_IS_TLS13(s)) {
2042         sk_SSL_CIPHER_free(s->session->ciphers);
2043         s->session->ciphers = ciphers;
2044         if (ciphers == NULL) {
2045             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2046                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2047                      ERR_R_INTERNAL_ERROR);
2048             goto err;
2049         }
2050         ciphers = NULL;
2051     }
2052 
2053     if (!s->hit) {
2054 #ifdef OPENSSL_NO_COMP
2055         s->session->compress_meth = 0;
2056 #else
2057         s->session->compress_meth = (comp == NULL) ? 0 : comp->id;
2058 #endif
2059         if (!tls1_set_server_sigalgs(s)) {
2060             /* SSLfatal() already called */
2061             goto err;
2062         }
2063     }
2064 
2065     sk_SSL_CIPHER_free(ciphers);
2066     sk_SSL_CIPHER_free(scsvs);
2067     OPENSSL_free(clienthello->pre_proc_exts);
2068     OPENSSL_free(s->clienthello);
2069     s->clienthello = NULL;
2070     return 1;
2071  err:
2072     sk_SSL_CIPHER_free(ciphers);
2073     sk_SSL_CIPHER_free(scsvs);
2074     OPENSSL_free(clienthello->pre_proc_exts);
2075     OPENSSL_free(s->clienthello);
2076     s->clienthello = NULL;
2077 
2078     return 0;
2079 }
2080 
2081 /*
2082  * Call the status request callback if needed. Upon success, returns 1.
2083  * Upon failure, returns 0.
2084  */
2085 static int tls_handle_status_request(SSL *s)
2086 {
2087     s->ext.status_expected = 0;
2088 
2089     /*
2090      * If status request then ask callback what to do. Note: this must be
2091      * called after servername callbacks in case the certificate has changed,
2092      * and must be called after the cipher has been chosen because this may
2093      * influence which certificate is sent
2094      */
2095     if (s->ext.status_type != TLSEXT_STATUSTYPE_nothing && s->ctx != NULL
2096             && s->ctx->ext.status_cb != NULL) {
2097         int ret;
2098 
2099         /* If no certificate can't return certificate status */
2100         if (s->s3->tmp.cert != NULL) {
2101             /*
2102              * Set current certificate to one we will use so SSL_get_certificate
2103              * et al can pick it up.
2104              */
2105             s->cert->key = s->s3->tmp.cert;
2106             ret = s->ctx->ext.status_cb(s, s->ctx->ext.status_arg);
2107             switch (ret) {
2108                 /* We don't want to send a status request response */
2109             case SSL_TLSEXT_ERR_NOACK:
2110                 s->ext.status_expected = 0;
2111                 break;
2112                 /* status request response should be sent */
2113             case SSL_TLSEXT_ERR_OK:
2114                 if (s->ext.ocsp.resp)
2115                     s->ext.status_expected = 1;
2116                 break;
2117                 /* something bad happened */
2118             case SSL_TLSEXT_ERR_ALERT_FATAL:
2119             default:
2120                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2121                          SSL_F_TLS_HANDLE_STATUS_REQUEST,
2122                          SSL_R_CLIENTHELLO_TLSEXT);
2123                 return 0;
2124             }
2125         }
2126     }
2127 
2128     return 1;
2129 }
2130 
2131 /*
2132  * Call the alpn_select callback if needed. Upon success, returns 1.
2133  * Upon failure, returns 0.
2134  */
2135 int tls_handle_alpn(SSL *s)
2136 {
2137     const unsigned char *selected = NULL;
2138     unsigned char selected_len = 0;
2139 
2140     if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
2141         int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
2142                                            s->s3->alpn_proposed,
2143                                            (unsigned int)s->s3->alpn_proposed_len,
2144                                            s->ctx->ext.alpn_select_cb_arg);
2145 
2146         if (r == SSL_TLSEXT_ERR_OK) {
2147             OPENSSL_free(s->s3->alpn_selected);
2148             s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
2149             if (s->s3->alpn_selected == NULL) {
2150                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_HANDLE_ALPN,
2151                          ERR_R_INTERNAL_ERROR);
2152                 return 0;
2153             }
2154             s->s3->alpn_selected_len = selected_len;
2155 #ifndef OPENSSL_NO_NEXTPROTONEG
2156             /* ALPN takes precedence over NPN. */
2157             s->s3->npn_seen = 0;
2158 #endif
2159 
2160             /* Check ALPN is consistent with session */
2161             if (s->session->ext.alpn_selected == NULL
2162                         || selected_len != s->session->ext.alpn_selected_len
2163                         || memcmp(selected, s->session->ext.alpn_selected,
2164                                   selected_len) != 0) {
2165                 /* Not consistent so can't be used for early_data */
2166                 s->ext.early_data_ok = 0;
2167 
2168                 if (!s->hit) {
2169                     /*
2170                      * This is a new session and so alpn_selected should have
2171                      * been initialised to NULL. We should update it with the
2172                      * selected ALPN.
2173                      */
2174                     if (!ossl_assert(s->session->ext.alpn_selected == NULL)) {
2175                         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2176                                  SSL_F_TLS_HANDLE_ALPN,
2177                                  ERR_R_INTERNAL_ERROR);
2178                         return 0;
2179                     }
2180                     s->session->ext.alpn_selected = OPENSSL_memdup(selected,
2181                                                                    selected_len);
2182                     if (s->session->ext.alpn_selected == NULL) {
2183                         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2184                                  SSL_F_TLS_HANDLE_ALPN,
2185                                  ERR_R_INTERNAL_ERROR);
2186                         return 0;
2187                     }
2188                     s->session->ext.alpn_selected_len = selected_len;
2189                 }
2190             }
2191 
2192             return 1;
2193         } else if (r != SSL_TLSEXT_ERR_NOACK) {
2194             SSLfatal(s, SSL_AD_NO_APPLICATION_PROTOCOL, SSL_F_TLS_HANDLE_ALPN,
2195                      SSL_R_NO_APPLICATION_PROTOCOL);
2196             return 0;
2197         }
2198         /*
2199          * If r == SSL_TLSEXT_ERR_NOACK then behave as if no callback was
2200          * present.
2201          */
2202     }
2203 
2204     /* Check ALPN is consistent with session */
2205     if (s->session->ext.alpn_selected != NULL) {
2206         /* Not consistent so can't be used for early_data */
2207         s->ext.early_data_ok = 0;
2208     }
2209 
2210     return 1;
2211 }
2212 
2213 WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
2214 {
2215     const SSL_CIPHER *cipher;
2216 
2217     if (wst == WORK_MORE_A) {
2218         int rv = tls_early_post_process_client_hello(s);
2219         if (rv == 0) {
2220             /* SSLfatal() was already called */
2221             goto err;
2222         }
2223         if (rv < 0)
2224             return WORK_MORE_A;
2225         wst = WORK_MORE_B;
2226     }
2227     if (wst == WORK_MORE_B) {
2228         if (!s->hit || SSL_IS_TLS13(s)) {
2229             /* Let cert callback update server certificates if required */
2230             if (!s->hit && s->cert->cert_cb != NULL) {
2231                 int rv = s->cert->cert_cb(s, s->cert->cert_cb_arg);
2232                 if (rv == 0) {
2233                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2234                              SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
2235                              SSL_R_CERT_CB_ERROR);
2236                     goto err;
2237                 }
2238                 if (rv < 0) {
2239                     s->rwstate = SSL_X509_LOOKUP;
2240                     return WORK_MORE_B;
2241                 }
2242                 s->rwstate = SSL_NOTHING;
2243             }
2244 
2245             /* In TLSv1.3 we selected the ciphersuite before resumption */
2246             if (!SSL_IS_TLS13(s)) {
2247                 cipher =
2248                     ssl3_choose_cipher(s, s->session->ciphers, SSL_get_ciphers(s));
2249 
2250                 if (cipher == NULL) {
2251                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2252                              SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
2253                              SSL_R_NO_SHARED_CIPHER);
2254                     goto err;
2255                 }
2256                 s->s3->tmp.new_cipher = cipher;
2257             }
2258             if (!s->hit) {
2259                 if (!tls_choose_sigalg(s, 1)) {
2260                     /* SSLfatal already called */
2261                     goto err;
2262                 }
2263                 /* check whether we should disable session resumption */
2264                 if (s->not_resumable_session_cb != NULL)
2265                     s->session->not_resumable =
2266                         s->not_resumable_session_cb(s,
2267                             ((s->s3->tmp.new_cipher->algorithm_mkey
2268                               & (SSL_kDHE | SSL_kECDHE)) != 0));
2269                 if (s->session->not_resumable)
2270                     /* do not send a session ticket */
2271                     s->ext.ticket_expected = 0;
2272             }
2273         } else {
2274             /* Session-id reuse */
2275             s->s3->tmp.new_cipher = s->session->cipher;
2276         }
2277 
2278         /*-
2279          * we now have the following setup.
2280          * client_random
2281          * cipher_list          - our preferred list of ciphers
2282          * ciphers              - the clients preferred list of ciphers
2283          * compression          - basically ignored right now
2284          * ssl version is set   - sslv3
2285          * s->session           - The ssl session has been setup.
2286          * s->hit               - session reuse flag
2287          * s->s3->tmp.new_cipher- the new cipher to use.
2288          */
2289 
2290         /*
2291          * Call status_request callback if needed. Has to be done after the
2292          * certificate callbacks etc above.
2293          */
2294         if (!tls_handle_status_request(s)) {
2295             /* SSLfatal() already called */
2296             goto err;
2297         }
2298         /*
2299          * Call alpn_select callback if needed.  Has to be done after SNI and
2300          * cipher negotiation (HTTP/2 restricts permitted ciphers). In TLSv1.3
2301          * we already did this because cipher negotiation happens earlier, and
2302          * we must handle ALPN before we decide whether to accept early_data.
2303          */
2304         if (!SSL_IS_TLS13(s) && !tls_handle_alpn(s)) {
2305             /* SSLfatal() already called */
2306             goto err;
2307         }
2308 
2309         wst = WORK_MORE_C;
2310     }
2311 #ifndef OPENSSL_NO_SRP
2312     if (wst == WORK_MORE_C) {
2313         int ret;
2314         if ((ret = ssl_check_srp_ext_ClientHello(s)) == 0) {
2315             /*
2316              * callback indicates further work to be done
2317              */
2318             s->rwstate = SSL_X509_LOOKUP;
2319             return WORK_MORE_C;
2320         }
2321         if (ret < 0) {
2322             /* SSLfatal() already called */
2323             goto err;
2324         }
2325     }
2326 #endif
2327 
2328     return WORK_FINISHED_STOP;
2329  err:
2330     return WORK_ERROR;
2331 }
2332 
2333 int tls_construct_server_hello(SSL *s, WPACKET *pkt)
2334 {
2335     int compm;
2336     size_t sl, len;
2337     int version;
2338     unsigned char *session_id;
2339     int usetls13 = SSL_IS_TLS13(s) || s->hello_retry_request == SSL_HRR_PENDING;
2340 
2341     version = usetls13 ? TLS1_2_VERSION : s->version;
2342     if (!WPACKET_put_bytes_u16(pkt, version)
2343                /*
2344                 * Random stuff. Filling of the server_random takes place in
2345                 * tls_process_client_hello()
2346                 */
2347             || !WPACKET_memcpy(pkt,
2348                                s->hello_retry_request == SSL_HRR_PENDING
2349                                    ? hrrrandom : s->s3->server_random,
2350                                SSL3_RANDOM_SIZE)) {
2351         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_SERVER_HELLO,
2352                  ERR_R_INTERNAL_ERROR);
2353         return 0;
2354     }
2355 
2356     /*-
2357      * There are several cases for the session ID to send
2358      * back in the server hello:
2359      * - For session reuse from the session cache,
2360      *   we send back the old session ID.
2361      * - If stateless session reuse (using a session ticket)
2362      *   is successful, we send back the client's "session ID"
2363      *   (which doesn't actually identify the session).
2364      * - If it is a new session, we send back the new
2365      *   session ID.
2366      * - However, if we want the new session to be single-use,
2367      *   we send back a 0-length session ID.
2368      * - In TLSv1.3 we echo back the session id sent to us by the client
2369      *   regardless
2370      * s->hit is non-zero in either case of session reuse,
2371      * so the following won't overwrite an ID that we're supposed
2372      * to send back.
2373      */
2374     if (s->session->not_resumable ||
2375         (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)
2376          && !s->hit))
2377         s->session->session_id_length = 0;
2378 
2379     if (usetls13) {
2380         sl = s->tmp_session_id_len;
2381         session_id = s->tmp_session_id;
2382     } else {
2383         sl = s->session->session_id_length;
2384         session_id = s->session->session_id;
2385     }
2386 
2387     if (sl > sizeof(s->session->session_id)) {
2388         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_SERVER_HELLO,
2389                  ERR_R_INTERNAL_ERROR);
2390         return 0;
2391     }
2392 
2393     /* set up the compression method */
2394 #ifdef OPENSSL_NO_COMP
2395     compm = 0;
2396 #else
2397     if (usetls13 || s->s3->tmp.new_compression == NULL)
2398         compm = 0;
2399     else
2400         compm = s->s3->tmp.new_compression->id;
2401 #endif
2402 
2403     if (!WPACKET_sub_memcpy_u8(pkt, session_id, sl)
2404             || !s->method->put_cipher_by_char(s->s3->tmp.new_cipher, pkt, &len)
2405             || !WPACKET_put_bytes_u8(pkt, compm)) {
2406         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_SERVER_HELLO,
2407                  ERR_R_INTERNAL_ERROR);
2408         return 0;
2409     }
2410 
2411     if (!tls_construct_extensions(s, pkt,
2412                                   s->hello_retry_request == SSL_HRR_PENDING
2413                                       ? SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
2414                                       : (SSL_IS_TLS13(s)
2415                                           ? SSL_EXT_TLS1_3_SERVER_HELLO
2416                                           : SSL_EXT_TLS1_2_SERVER_HELLO),
2417                                   NULL, 0)) {
2418         /* SSLfatal() already called */
2419         return 0;
2420     }
2421 
2422     if (s->hello_retry_request == SSL_HRR_PENDING) {
2423         /* Ditch the session. We'll create a new one next time around */
2424         SSL_SESSION_free(s->session);
2425         s->session = NULL;
2426         s->hit = 0;
2427 
2428         /*
2429          * Re-initialise the Transcript Hash. We're going to prepopulate it with
2430          * a synthetic message_hash in place of ClientHello1.
2431          */
2432         if (!create_synthetic_message_hash(s, NULL, 0, NULL, 0)) {
2433             /* SSLfatal() already called */
2434             return 0;
2435         }
2436     } else if (!(s->verify_mode & SSL_VERIFY_PEER)
2437                 && !ssl3_digest_cached_records(s, 0)) {
2438         /* SSLfatal() already called */;
2439         return 0;
2440     }
2441 
2442     return 1;
2443 }
2444 
2445 int tls_construct_server_done(SSL *s, WPACKET *pkt)
2446 {
2447     if (!s->s3->tmp.cert_request) {
2448         if (!ssl3_digest_cached_records(s, 0)) {
2449             /* SSLfatal() already called */
2450             return 0;
2451         }
2452     }
2453     return 1;
2454 }
2455 
2456 int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
2457 {
2458 #ifndef OPENSSL_NO_DH
2459     EVP_PKEY *pkdh = NULL;
2460 #endif
2461 #ifndef OPENSSL_NO_EC
2462     unsigned char *encodedPoint = NULL;
2463     size_t encodedlen = 0;
2464     int curve_id = 0;
2465 #endif
2466     const SIGALG_LOOKUP *lu = s->s3->tmp.sigalg;
2467     int i;
2468     unsigned long type;
2469     const BIGNUM *r[4];
2470     EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
2471     EVP_PKEY_CTX *pctx = NULL;
2472     size_t paramlen, paramoffset;
2473 
2474     if (!WPACKET_get_total_written(pkt, &paramoffset)) {
2475         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2476                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
2477         goto err;
2478     }
2479 
2480     if (md_ctx == NULL) {
2481         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2482                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
2483         goto err;
2484     }
2485 
2486     type = s->s3->tmp.new_cipher->algorithm_mkey;
2487 
2488     r[0] = r[1] = r[2] = r[3] = NULL;
2489 #ifndef OPENSSL_NO_PSK
2490     /* Plain PSK or RSAPSK nothing to do */
2491     if (type & (SSL_kPSK | SSL_kRSAPSK)) {
2492     } else
2493 #endif                          /* !OPENSSL_NO_PSK */
2494 #ifndef OPENSSL_NO_DH
2495     if (type & (SSL_kDHE | SSL_kDHEPSK)) {
2496         CERT *cert = s->cert;
2497 
2498         EVP_PKEY *pkdhp = NULL;
2499         DH *dh;
2500 
2501         if (s->cert->dh_tmp_auto) {
2502             DH *dhp = ssl_get_auto_dh(s);
2503             pkdh = EVP_PKEY_new();
2504             if (pkdh == NULL || dhp == NULL) {
2505                 DH_free(dhp);
2506                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2507                          SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2508                          ERR_R_INTERNAL_ERROR);
2509                 goto err;
2510             }
2511             EVP_PKEY_assign_DH(pkdh, dhp);
2512             pkdhp = pkdh;
2513         } else {
2514             pkdhp = cert->dh_tmp;
2515         }
2516         if ((pkdhp == NULL) && (s->cert->dh_tmp_cb != NULL)) {
2517             DH *dhp = s->cert->dh_tmp_cb(s, 0, 1024);
2518             pkdh = ssl_dh_to_pkey(dhp);
2519             if (pkdh == NULL) {
2520                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2521                          SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2522                          ERR_R_INTERNAL_ERROR);
2523                 goto err;
2524             }
2525             pkdhp = pkdh;
2526         }
2527         if (pkdhp == NULL) {
2528             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2529                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2530                      SSL_R_MISSING_TMP_DH_KEY);
2531             goto err;
2532         }
2533         if (!ssl_security(s, SSL_SECOP_TMP_DH,
2534                           EVP_PKEY_security_bits(pkdhp), 0, pkdhp)) {
2535             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2536                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2537                      SSL_R_DH_KEY_TOO_SMALL);
2538             goto err;
2539         }
2540         if (s->s3->tmp.pkey != NULL) {
2541             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2542                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2543                      ERR_R_INTERNAL_ERROR);
2544             goto err;
2545         }
2546 
2547         s->s3->tmp.pkey = ssl_generate_pkey(pkdhp);
2548         if (s->s3->tmp.pkey == NULL) {
2549             /* SSLfatal() already called */
2550             goto err;
2551         }
2552 
2553         dh = EVP_PKEY_get0_DH(s->s3->tmp.pkey);
2554         if (dh == NULL) {
2555             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2556                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2557                      ERR_R_INTERNAL_ERROR);
2558             goto err;
2559         }
2560 
2561         EVP_PKEY_free(pkdh);
2562         pkdh = NULL;
2563 
2564         DH_get0_pqg(dh, &r[0], NULL, &r[1]);
2565         DH_get0_key(dh, &r[2], NULL);
2566     } else
2567 #endif
2568 #ifndef OPENSSL_NO_EC
2569     if (type & (SSL_kECDHE | SSL_kECDHEPSK)) {
2570 
2571         if (s->s3->tmp.pkey != NULL) {
2572             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2573                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2574                      ERR_R_INTERNAL_ERROR);
2575             goto err;
2576         }
2577 
2578         /* Get NID of appropriate shared curve */
2579         curve_id = tls1_shared_group(s, -2);
2580         if (curve_id == 0) {
2581             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2582                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2583                      SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
2584             goto err;
2585         }
2586         s->s3->tmp.pkey = ssl_generate_pkey_group(s, curve_id);
2587         /* Generate a new key for this curve */
2588         if (s->s3->tmp.pkey == NULL) {
2589             /* SSLfatal() already called */
2590             goto err;
2591         }
2592 
2593         /* Encode the public key. */
2594         encodedlen = EVP_PKEY_get1_tls_encodedpoint(s->s3->tmp.pkey,
2595                                                     &encodedPoint);
2596         if (encodedlen == 0) {
2597             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2598                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_EC_LIB);
2599             goto err;
2600         }
2601 
2602         /*
2603          * We'll generate the serverKeyExchange message explicitly so we
2604          * can set these to NULLs
2605          */
2606         r[0] = NULL;
2607         r[1] = NULL;
2608         r[2] = NULL;
2609         r[3] = NULL;
2610     } else
2611 #endif                          /* !OPENSSL_NO_EC */
2612 #ifndef OPENSSL_NO_SRP
2613     if (type & SSL_kSRP) {
2614         if ((s->srp_ctx.N == NULL) ||
2615             (s->srp_ctx.g == NULL) ||
2616             (s->srp_ctx.s == NULL) || (s->srp_ctx.B == NULL)) {
2617             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2618                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2619                      SSL_R_MISSING_SRP_PARAM);
2620             goto err;
2621         }
2622         r[0] = s->srp_ctx.N;
2623         r[1] = s->srp_ctx.g;
2624         r[2] = s->srp_ctx.s;
2625         r[3] = s->srp_ctx.B;
2626     } else
2627 #endif
2628     {
2629         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2630                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2631                  SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
2632         goto err;
2633     }
2634 
2635     if (((s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aSRP)) != 0)
2636         || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) != 0) {
2637         lu = NULL;
2638     } else if (lu == NULL) {
2639         SSLfatal(s, SSL_AD_DECODE_ERROR,
2640                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
2641         goto err;
2642     }
2643 
2644 #ifndef OPENSSL_NO_PSK
2645     if (type & SSL_PSK) {
2646         size_t len = (s->cert->psk_identity_hint == NULL)
2647                         ? 0 : strlen(s->cert->psk_identity_hint);
2648 
2649         /*
2650          * It should not happen that len > PSK_MAX_IDENTITY_LEN - we already
2651          * checked this when we set the identity hint - but just in case
2652          */
2653         if (len > PSK_MAX_IDENTITY_LEN
2654                 || !WPACKET_sub_memcpy_u16(pkt, s->cert->psk_identity_hint,
2655                                            len)) {
2656             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2657                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2658                      ERR_R_INTERNAL_ERROR);
2659             goto err;
2660         }
2661     }
2662 #endif
2663 
2664     for (i = 0; i < 4 && r[i] != NULL; i++) {
2665         unsigned char *binval;
2666         int res;
2667 
2668 #ifndef OPENSSL_NO_SRP
2669         if ((i == 2) && (type & SSL_kSRP)) {
2670             res = WPACKET_start_sub_packet_u8(pkt);
2671         } else
2672 #endif
2673             res = WPACKET_start_sub_packet_u16(pkt);
2674 
2675         if (!res) {
2676             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2677                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2678                      ERR_R_INTERNAL_ERROR);
2679             goto err;
2680         }
2681 
2682 #ifndef OPENSSL_NO_DH
2683         /*-
2684          * for interoperability with some versions of the Microsoft TLS
2685          * stack, we need to zero pad the DHE pub key to the same length
2686          * as the prime
2687          */
2688         if ((i == 2) && (type & (SSL_kDHE | SSL_kDHEPSK))) {
2689             size_t len = BN_num_bytes(r[0]) - BN_num_bytes(r[2]);
2690 
2691             if (len > 0) {
2692                 if (!WPACKET_allocate_bytes(pkt, len, &binval)) {
2693                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2694                              SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2695                              ERR_R_INTERNAL_ERROR);
2696                     goto err;
2697                 }
2698                 memset(binval, 0, len);
2699             }
2700         }
2701 #endif
2702         if (!WPACKET_allocate_bytes(pkt, BN_num_bytes(r[i]), &binval)
2703                 || !WPACKET_close(pkt)) {
2704             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2705                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2706                      ERR_R_INTERNAL_ERROR);
2707             goto err;
2708         }
2709 
2710         BN_bn2bin(r[i], binval);
2711     }
2712 
2713 #ifndef OPENSSL_NO_EC
2714     if (type & (SSL_kECDHE | SSL_kECDHEPSK)) {
2715         /*
2716          * We only support named (not generic) curves. In this situation, the
2717          * ServerKeyExchange message has: [1 byte CurveType], [2 byte CurveName]
2718          * [1 byte length of encoded point], followed by the actual encoded
2719          * point itself
2720          */
2721         if (!WPACKET_put_bytes_u8(pkt, NAMED_CURVE_TYPE)
2722                 || !WPACKET_put_bytes_u8(pkt, 0)
2723                 || !WPACKET_put_bytes_u8(pkt, curve_id)
2724                 || !WPACKET_sub_memcpy_u8(pkt, encodedPoint, encodedlen)) {
2725             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2726                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2727                      ERR_R_INTERNAL_ERROR);
2728             goto err;
2729         }
2730         OPENSSL_free(encodedPoint);
2731         encodedPoint = NULL;
2732     }
2733 #endif
2734 
2735     /* not anonymous */
2736     if (lu != NULL) {
2737         EVP_PKEY *pkey = s->s3->tmp.cert->privatekey;
2738         const EVP_MD *md;
2739         unsigned char *sigbytes1, *sigbytes2, *tbs;
2740         size_t siglen, tbslen;
2741         int rv;
2742 
2743         if (pkey == NULL || !tls1_lookup_md(lu, &md)) {
2744             /* Should never happen */
2745             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2746                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2747                      ERR_R_INTERNAL_ERROR);
2748             goto err;
2749         }
2750         /* Get length of the parameters we have written above */
2751         if (!WPACKET_get_length(pkt, &paramlen)) {
2752             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2753                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2754                      ERR_R_INTERNAL_ERROR);
2755             goto err;
2756         }
2757         /* send signature algorithm */
2758         if (SSL_USE_SIGALGS(s) && !WPACKET_put_bytes_u16(pkt, lu->sigalg)) {
2759             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2760                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2761                      ERR_R_INTERNAL_ERROR);
2762             goto err;
2763         }
2764         /*
2765          * Create the signature. We don't know the actual length of the sig
2766          * until after we've created it, so we reserve enough bytes for it
2767          * up front, and then properly allocate them in the WPACKET
2768          * afterwards.
2769          */
2770         siglen = EVP_PKEY_size(pkey);
2771         if (!WPACKET_sub_reserve_bytes_u16(pkt, siglen, &sigbytes1)
2772             || EVP_DigestSignInit(md_ctx, &pctx, md, NULL, pkey) <= 0) {
2773             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2774                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2775                      ERR_R_INTERNAL_ERROR);
2776             goto err;
2777         }
2778         if (lu->sig == EVP_PKEY_RSA_PSS) {
2779             if (EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) <= 0
2780                 || EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST) <= 0) {
2781                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2782                          SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2783                         ERR_R_EVP_LIB);
2784                 goto err;
2785             }
2786         }
2787         tbslen = construct_key_exchange_tbs(s, &tbs,
2788                                             s->init_buf->data + paramoffset,
2789                                             paramlen);
2790         if (tbslen == 0) {
2791             /* SSLfatal() already called */
2792             goto err;
2793         }
2794         rv = EVP_DigestSign(md_ctx, sigbytes1, &siglen, tbs, tbslen);
2795         OPENSSL_free(tbs);
2796         if (rv <= 0 || !WPACKET_sub_allocate_bytes_u16(pkt, siglen, &sigbytes2)
2797             || sigbytes1 != sigbytes2) {
2798             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2799                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2800                      ERR_R_INTERNAL_ERROR);
2801             goto err;
2802         }
2803     }
2804 
2805     EVP_MD_CTX_free(md_ctx);
2806     return 1;
2807  err:
2808 #ifndef OPENSSL_NO_DH
2809     EVP_PKEY_free(pkdh);
2810 #endif
2811 #ifndef OPENSSL_NO_EC
2812     OPENSSL_free(encodedPoint);
2813 #endif
2814     EVP_MD_CTX_free(md_ctx);
2815     return 0;
2816 }
2817 
2818 int tls_construct_certificate_request(SSL *s, WPACKET *pkt)
2819 {
2820     if (SSL_IS_TLS13(s)) {
2821         /* Send random context when doing post-handshake auth */
2822         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
2823             OPENSSL_free(s->pha_context);
2824             s->pha_context_len = 32;
2825             if ((s->pha_context = OPENSSL_malloc(s->pha_context_len)) == NULL
2826                     || RAND_bytes(s->pha_context, s->pha_context_len) <= 0
2827                     || !WPACKET_sub_memcpy_u8(pkt, s->pha_context, s->pha_context_len)) {
2828                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2829                          SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2830                          ERR_R_INTERNAL_ERROR);
2831                 return 0;
2832             }
2833             /* reset the handshake hash back to just after the ClientFinished */
2834             if (!tls13_restore_handshake_digest_for_pha(s)) {
2835                 /* SSLfatal() already called */
2836                 return 0;
2837             }
2838         } else {
2839             if (!WPACKET_put_bytes_u8(pkt, 0)) {
2840                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2841                          SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2842                          ERR_R_INTERNAL_ERROR);
2843                 return 0;
2844             }
2845         }
2846 
2847         if (!tls_construct_extensions(s, pkt,
2848                                       SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, NULL,
2849                                       0)) {
2850             /* SSLfatal() already called */
2851             return 0;
2852         }
2853         goto done;
2854     }
2855 
2856     /* get the list of acceptable cert types */
2857     if (!WPACKET_start_sub_packet_u8(pkt)
2858         || !ssl3_get_req_cert_type(s, pkt) || !WPACKET_close(pkt)) {
2859         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2860                  SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST, ERR_R_INTERNAL_ERROR);
2861         return 0;
2862     }
2863 
2864     if (SSL_USE_SIGALGS(s)) {
2865         const uint16_t *psigs;
2866         size_t nl = tls12_get_psigalgs(s, 1, &psigs);
2867 
2868         if (!WPACKET_start_sub_packet_u16(pkt)
2869                 || !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)
2870                 || !tls12_copy_sigalgs(s, pkt, psigs, nl)
2871                 || !WPACKET_close(pkt)) {
2872             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2873                      SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2874                      ERR_R_INTERNAL_ERROR);
2875             return 0;
2876         }
2877     }
2878 
2879     if (!construct_ca_names(s, pkt)) {
2880         /* SSLfatal() already called */
2881         return 0;
2882     }
2883 
2884  done:
2885     s->certreqs_sent++;
2886     s->s3->tmp.cert_request = 1;
2887     return 1;
2888 }
2889 
2890 static int tls_process_cke_psk_preamble(SSL *s, PACKET *pkt)
2891 {
2892 #ifndef OPENSSL_NO_PSK
2893     unsigned char psk[PSK_MAX_PSK_LEN];
2894     size_t psklen;
2895     PACKET psk_identity;
2896 
2897     if (!PACKET_get_length_prefixed_2(pkt, &psk_identity)) {
2898         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2899                  SSL_R_LENGTH_MISMATCH);
2900         return 0;
2901     }
2902     if (PACKET_remaining(&psk_identity) > PSK_MAX_IDENTITY_LEN) {
2903         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2904                  SSL_R_DATA_LENGTH_TOO_LONG);
2905         return 0;
2906     }
2907     if (s->psk_server_callback == NULL) {
2908         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2909                  SSL_R_PSK_NO_SERVER_CB);
2910         return 0;
2911     }
2912 
2913     if (!PACKET_strndup(&psk_identity, &s->session->psk_identity)) {
2914         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2915                  ERR_R_INTERNAL_ERROR);
2916         return 0;
2917     }
2918 
2919     psklen = s->psk_server_callback(s, s->session->psk_identity,
2920                                     psk, sizeof(psk));
2921 
2922     if (psklen > PSK_MAX_PSK_LEN) {
2923         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2924                  ERR_R_INTERNAL_ERROR);
2925         return 0;
2926     } else if (psklen == 0) {
2927         /*
2928          * PSK related to the given identity not found
2929          */
2930         SSLfatal(s, SSL_AD_UNKNOWN_PSK_IDENTITY,
2931                  SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2932                  SSL_R_PSK_IDENTITY_NOT_FOUND);
2933         return 0;
2934     }
2935 
2936     OPENSSL_free(s->s3->tmp.psk);
2937     s->s3->tmp.psk = OPENSSL_memdup(psk, psklen);
2938     OPENSSL_cleanse(psk, psklen);
2939 
2940     if (s->s3->tmp.psk == NULL) {
2941         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2942                  SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE, ERR_R_MALLOC_FAILURE);
2943         return 0;
2944     }
2945 
2946     s->s3->tmp.psklen = psklen;
2947 
2948     return 1;
2949 #else
2950     /* Should never happen */
2951     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2952              ERR_R_INTERNAL_ERROR);
2953     return 0;
2954 #endif
2955 }
2956 
2957 static int tls_process_cke_rsa(SSL *s, PACKET *pkt)
2958 {
2959 #ifndef OPENSSL_NO_RSA
2960     unsigned char rand_premaster_secret[SSL_MAX_MASTER_KEY_LENGTH];
2961     int decrypt_len;
2962     unsigned char decrypt_good, version_good;
2963     size_t j, padding_len;
2964     PACKET enc_premaster;
2965     RSA *rsa = NULL;
2966     unsigned char *rsa_decrypt = NULL;
2967     int ret = 0;
2968 
2969     rsa = EVP_PKEY_get0_RSA(s->cert->pkeys[SSL_PKEY_RSA].privatekey);
2970     if (rsa == NULL) {
2971         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
2972                  SSL_R_MISSING_RSA_CERTIFICATE);
2973         return 0;
2974     }
2975 
2976     /* SSLv3 and pre-standard DTLS omit the length bytes. */
2977     if (s->version == SSL3_VERSION || s->version == DTLS1_BAD_VER) {
2978         enc_premaster = *pkt;
2979     } else {
2980         if (!PACKET_get_length_prefixed_2(pkt, &enc_premaster)
2981             || PACKET_remaining(pkt) != 0) {
2982             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
2983                      SSL_R_LENGTH_MISMATCH);
2984             return 0;
2985         }
2986     }
2987 
2988     /*
2989      * We want to be sure that the plaintext buffer size makes it safe to
2990      * iterate over the entire size of a premaster secret
2991      * (SSL_MAX_MASTER_KEY_LENGTH). Reject overly short RSA keys because
2992      * their ciphertext cannot accommodate a premaster secret anyway.
2993      */
2994     if (RSA_size(rsa) < SSL_MAX_MASTER_KEY_LENGTH) {
2995         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
2996                  RSA_R_KEY_SIZE_TOO_SMALL);
2997         return 0;
2998     }
2999 
3000     rsa_decrypt = OPENSSL_malloc(RSA_size(rsa));
3001     if (rsa_decrypt == NULL) {
3002         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3003                  ERR_R_MALLOC_FAILURE);
3004         return 0;
3005     }
3006 
3007     /*
3008      * We must not leak whether a decryption failure occurs because of
3009      * Bleichenbacher's attack on PKCS #1 v1.5 RSA padding (see RFC 2246,
3010      * section 7.4.7.1). The code follows that advice of the TLS RFC and
3011      * generates a random premaster secret for the case that the decrypt
3012      * fails. See https://tools.ietf.org/html/rfc5246#section-7.4.7.1
3013      */
3014 
3015     if (RAND_priv_bytes(rand_premaster_secret,
3016                       sizeof(rand_premaster_secret)) <= 0) {
3017         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3018                  ERR_R_INTERNAL_ERROR);
3019         goto err;
3020     }
3021 
3022     /*
3023      * Decrypt with no padding. PKCS#1 padding will be removed as part of
3024      * the timing-sensitive code below.
3025      */
3026      /* TODO(size_t): Convert this function */
3027     decrypt_len = (int)RSA_private_decrypt((int)PACKET_remaining(&enc_premaster),
3028                                            PACKET_data(&enc_premaster),
3029                                            rsa_decrypt, rsa, RSA_NO_PADDING);
3030     if (decrypt_len < 0) {
3031         SSLfatal(s, SSL_AD_DECRYPT_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3032                  ERR_R_INTERNAL_ERROR);
3033         goto err;
3034     }
3035 
3036     /* Check the padding. See RFC 3447, section 7.2.2. */
3037 
3038     /*
3039      * The smallest padded premaster is 11 bytes of overhead. Small keys
3040      * are publicly invalid, so this may return immediately. This ensures
3041      * PS is at least 8 bytes.
3042      */
3043     if (decrypt_len < 11 + SSL_MAX_MASTER_KEY_LENGTH) {
3044         SSLfatal(s, SSL_AD_DECRYPT_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3045                  SSL_R_DECRYPTION_FAILED);
3046         goto err;
3047     }
3048 
3049     padding_len = decrypt_len - SSL_MAX_MASTER_KEY_LENGTH;
3050     decrypt_good = constant_time_eq_int_8(rsa_decrypt[0], 0) &
3051         constant_time_eq_int_8(rsa_decrypt[1], 2);
3052     for (j = 2; j < padding_len - 1; j++) {
3053         decrypt_good &= ~constant_time_is_zero_8(rsa_decrypt[j]);
3054     }
3055     decrypt_good &= constant_time_is_zero_8(rsa_decrypt[padding_len - 1]);
3056 
3057     /*
3058      * If the version in the decrypted pre-master secret is correct then
3059      * version_good will be 0xff, otherwise it'll be zero. The
3060      * Klima-Pokorny-Rosa extension of Bleichenbacher's attack
3061      * (http://eprint.iacr.org/2003/052/) exploits the version number
3062      * check as a "bad version oracle". Thus version checks are done in
3063      * constant time and are treated like any other decryption error.
3064      */
3065     version_good =
3066         constant_time_eq_8(rsa_decrypt[padding_len],
3067                            (unsigned)(s->client_version >> 8));
3068     version_good &=
3069         constant_time_eq_8(rsa_decrypt[padding_len + 1],
3070                            (unsigned)(s->client_version & 0xff));
3071 
3072     /*
3073      * The premaster secret must contain the same version number as the
3074      * ClientHello to detect version rollback attacks (strangely, the
3075      * protocol does not offer such protection for DH ciphersuites).
3076      * However, buggy clients exist that send the negotiated protocol
3077      * version instead if the server does not support the requested
3078      * protocol version. If SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such
3079      * clients.
3080      */
3081     if (s->options & SSL_OP_TLS_ROLLBACK_BUG) {
3082         unsigned char workaround_good;
3083         workaround_good = constant_time_eq_8(rsa_decrypt[padding_len],
3084                                              (unsigned)(s->version >> 8));
3085         workaround_good &=
3086             constant_time_eq_8(rsa_decrypt[padding_len + 1],
3087                                (unsigned)(s->version & 0xff));
3088         version_good |= workaround_good;
3089     }
3090 
3091     /*
3092      * Both decryption and version must be good for decrypt_good to
3093      * remain non-zero (0xff).
3094      */
3095     decrypt_good &= version_good;
3096 
3097     /*
3098      * Now copy rand_premaster_secret over from p using
3099      * decrypt_good_mask. If decryption failed, then p does not
3100      * contain valid plaintext, however, a check above guarantees
3101      * it is still sufficiently large to read from.
3102      */
3103     for (j = 0; j < sizeof(rand_premaster_secret); j++) {
3104         rsa_decrypt[padding_len + j] =
3105             constant_time_select_8(decrypt_good,
3106                                    rsa_decrypt[padding_len + j],
3107                                    rand_premaster_secret[j]);
3108     }
3109 
3110     if (!ssl_generate_master_secret(s, rsa_decrypt + padding_len,
3111                                     sizeof(rand_premaster_secret), 0)) {
3112         /* SSLfatal() already called */
3113         goto err;
3114     }
3115 
3116     ret = 1;
3117  err:
3118     OPENSSL_free(rsa_decrypt);
3119     return ret;
3120 #else
3121     /* Should never happen */
3122     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3123              ERR_R_INTERNAL_ERROR);
3124     return 0;
3125 #endif
3126 }
3127 
3128 static int tls_process_cke_dhe(SSL *s, PACKET *pkt)
3129 {
3130 #ifndef OPENSSL_NO_DH
3131     EVP_PKEY *skey = NULL;
3132     DH *cdh;
3133     unsigned int i;
3134     BIGNUM *pub_key;
3135     const unsigned char *data;
3136     EVP_PKEY *ckey = NULL;
3137     int ret = 0;
3138 
3139     if (!PACKET_get_net_2(pkt, &i) || PACKET_remaining(pkt) != i) {
3140         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3141                SSL_R_DH_PUBLIC_VALUE_LENGTH_IS_WRONG);
3142         goto err;
3143     }
3144     skey = s->s3->tmp.pkey;
3145     if (skey == NULL) {
3146         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3147                  SSL_R_MISSING_TMP_DH_KEY);
3148         goto err;
3149     }
3150 
3151     if (PACKET_remaining(pkt) == 0L) {
3152         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3153                  SSL_R_MISSING_TMP_DH_KEY);
3154         goto err;
3155     }
3156     if (!PACKET_get_bytes(pkt, &data, i)) {
3157         /* We already checked we have enough data */
3158         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3159                  ERR_R_INTERNAL_ERROR);
3160         goto err;
3161     }
3162     ckey = EVP_PKEY_new();
3163     if (ckey == NULL || EVP_PKEY_copy_parameters(ckey, skey) == 0) {
3164         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3165                  SSL_R_BN_LIB);
3166         goto err;
3167     }
3168 
3169     cdh = EVP_PKEY_get0_DH(ckey);
3170     pub_key = BN_bin2bn(data, i, NULL);
3171     if (pub_key == NULL || cdh == NULL || !DH_set0_key(cdh, pub_key, NULL)) {
3172         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3173                  ERR_R_INTERNAL_ERROR);
3174         BN_free(pub_key);
3175         goto err;
3176     }
3177 
3178     if (ssl_derive(s, skey, ckey, 1) == 0) {
3179         /* SSLfatal() already called */
3180         goto err;
3181     }
3182 
3183     ret = 1;
3184     EVP_PKEY_free(s->s3->tmp.pkey);
3185     s->s3->tmp.pkey = NULL;
3186  err:
3187     EVP_PKEY_free(ckey);
3188     return ret;
3189 #else
3190     /* Should never happen */
3191     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3192              ERR_R_INTERNAL_ERROR);
3193     return 0;
3194 #endif
3195 }
3196 
3197 static int tls_process_cke_ecdhe(SSL *s, PACKET *pkt)
3198 {
3199 #ifndef OPENSSL_NO_EC
3200     EVP_PKEY *skey = s->s3->tmp.pkey;
3201     EVP_PKEY *ckey = NULL;
3202     int ret = 0;
3203 
3204     if (PACKET_remaining(pkt) == 0L) {
3205         /* We don't support ECDH client auth */
3206         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PROCESS_CKE_ECDHE,
3207                  SSL_R_MISSING_TMP_ECDH_KEY);
3208         goto err;
3209     } else {
3210         unsigned int i;
3211         const unsigned char *data;
3212 
3213         /*
3214          * Get client's public key from encoded point in the
3215          * ClientKeyExchange message.
3216          */
3217 
3218         /* Get encoded point length */
3219         if (!PACKET_get_1(pkt, &i) || !PACKET_get_bytes(pkt, &data, i)
3220             || PACKET_remaining(pkt) != 0) {
3221             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3222                      SSL_R_LENGTH_MISMATCH);
3223             goto err;
3224         }
3225         ckey = EVP_PKEY_new();
3226         if (ckey == NULL || EVP_PKEY_copy_parameters(ckey, skey) <= 0) {
3227             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3228                      ERR_R_EVP_LIB);
3229             goto err;
3230         }
3231         if (EVP_PKEY_set1_tls_encodedpoint(ckey, data, i) == 0) {
3232             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3233                      ERR_R_EC_LIB);
3234             goto err;
3235         }
3236     }
3237 
3238     if (ssl_derive(s, skey, ckey, 1) == 0) {
3239         /* SSLfatal() already called */
3240         goto err;
3241     }
3242 
3243     ret = 1;
3244     EVP_PKEY_free(s->s3->tmp.pkey);
3245     s->s3->tmp.pkey = NULL;
3246  err:
3247     EVP_PKEY_free(ckey);
3248 
3249     return ret;
3250 #else
3251     /* Should never happen */
3252     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3253              ERR_R_INTERNAL_ERROR);
3254     return 0;
3255 #endif
3256 }
3257 
3258 static int tls_process_cke_srp(SSL *s, PACKET *pkt)
3259 {
3260 #ifndef OPENSSL_NO_SRP
3261     unsigned int i;
3262     const unsigned char *data;
3263 
3264     if (!PACKET_get_net_2(pkt, &i)
3265         || !PACKET_get_bytes(pkt, &data, i)) {
3266         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3267                  SSL_R_BAD_SRP_A_LENGTH);
3268         return 0;
3269     }
3270     if ((s->srp_ctx.A = BN_bin2bn(data, i, NULL)) == NULL) {
3271         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3272                  ERR_R_BN_LIB);
3273         return 0;
3274     }
3275     if (BN_ucmp(s->srp_ctx.A, s->srp_ctx.N) >= 0 || BN_is_zero(s->srp_ctx.A)) {
3276         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PROCESS_CKE_SRP,
3277                  SSL_R_BAD_SRP_PARAMETERS);
3278         return 0;
3279     }
3280     OPENSSL_free(s->session->srp_username);
3281     s->session->srp_username = OPENSSL_strdup(s->srp_ctx.login);
3282     if (s->session->srp_username == NULL) {
3283         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3284                  ERR_R_MALLOC_FAILURE);
3285         return 0;
3286     }
3287 
3288     if (!srp_generate_server_master_secret(s)) {
3289         /* SSLfatal() already called */
3290         return 0;
3291     }
3292 
3293     return 1;
3294 #else
3295     /* Should never happen */
3296     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3297              ERR_R_INTERNAL_ERROR);
3298     return 0;
3299 #endif
3300 }
3301 
3302 static int tls_process_cke_gost(SSL *s, PACKET *pkt)
3303 {
3304 #ifndef OPENSSL_NO_GOST
3305     EVP_PKEY_CTX *pkey_ctx;
3306     EVP_PKEY *client_pub_pkey = NULL, *pk = NULL;
3307     unsigned char premaster_secret[32];
3308     const unsigned char *start;
3309     size_t outlen = 32, inlen;
3310     unsigned long alg_a;
3311     unsigned int asn1id, asn1len;
3312     int ret = 0;
3313     PACKET encdata;
3314 
3315     /* Get our certificate private key */
3316     alg_a = s->s3->tmp.new_cipher->algorithm_auth;
3317     if (alg_a & SSL_aGOST12) {
3318         /*
3319          * New GOST ciphersuites have SSL_aGOST01 bit too
3320          */
3321         pk = s->cert->pkeys[SSL_PKEY_GOST12_512].privatekey;
3322         if (pk == NULL) {
3323             pk = s->cert->pkeys[SSL_PKEY_GOST12_256].privatekey;
3324         }
3325         if (pk == NULL) {
3326             pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
3327         }
3328     } else if (alg_a & SSL_aGOST01) {
3329         pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
3330     }
3331 
3332     pkey_ctx = EVP_PKEY_CTX_new(pk, NULL);
3333     if (pkey_ctx == NULL) {
3334         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3335                  ERR_R_MALLOC_FAILURE);
3336         return 0;
3337     }
3338     if (EVP_PKEY_decrypt_init(pkey_ctx) <= 0) {
3339         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3340                  ERR_R_INTERNAL_ERROR);
3341         return 0;
3342     }
3343     /*
3344      * If client certificate is present and is of the same type, maybe
3345      * use it for key exchange.  Don't mind errors from
3346      * EVP_PKEY_derive_set_peer, because it is completely valid to use a
3347      * client certificate for authorization only.
3348      */
3349     client_pub_pkey = X509_get0_pubkey(s->session->peer);
3350     if (client_pub_pkey) {
3351         if (EVP_PKEY_derive_set_peer(pkey_ctx, client_pub_pkey) <= 0)
3352             ERR_clear_error();
3353     }
3354     /* Decrypt session key */
3355     if (!PACKET_get_1(pkt, &asn1id)
3356             || asn1id != (V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)
3357             || !PACKET_peek_1(pkt, &asn1len)) {
3358         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3359                  SSL_R_DECRYPTION_FAILED);
3360         goto err;
3361     }
3362     if (asn1len == 0x81) {
3363         /*
3364          * Long form length. Should only be one byte of length. Anything else
3365          * isn't supported.
3366          * We did a successful peek before so this shouldn't fail
3367          */
3368         if (!PACKET_forward(pkt, 1)) {
3369             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3370                      SSL_R_DECRYPTION_FAILED);
3371             goto err;
3372         }
3373     } else  if (asn1len >= 0x80) {
3374         /*
3375          * Indefinite length, or more than one long form length bytes. We don't
3376          * support it
3377          */
3378         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3379                  SSL_R_DECRYPTION_FAILED);
3380         goto err;
3381     } /* else short form length */
3382 
3383     if (!PACKET_as_length_prefixed_1(pkt, &encdata)) {
3384         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3385                  SSL_R_DECRYPTION_FAILED);
3386         goto err;
3387     }
3388     inlen = PACKET_remaining(&encdata);
3389     start = PACKET_data(&encdata);
3390 
3391     if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen, start,
3392                          inlen) <= 0) {
3393         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3394                  SSL_R_DECRYPTION_FAILED);
3395         goto err;
3396     }
3397     /* Generate master secret */
3398     if (!ssl_generate_master_secret(s, premaster_secret,
3399                                     sizeof(premaster_secret), 0)) {
3400         /* SSLfatal() already called */
3401         goto err;
3402     }
3403     /* Check if pubkey from client certificate was used */
3404     if (EVP_PKEY_CTX_ctrl(pkey_ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 2,
3405                           NULL) > 0)
3406         s->statem.no_cert_verify = 1;
3407 
3408     ret = 1;
3409  err:
3410     EVP_PKEY_CTX_free(pkey_ctx);
3411     return ret;
3412 #else
3413     /* Should never happen */
3414     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3415              ERR_R_INTERNAL_ERROR);
3416     return 0;
3417 #endif
3418 }
3419 
3420 MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
3421 {
3422     unsigned long alg_k;
3423 
3424     alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
3425 
3426     /* For PSK parse and retrieve identity, obtain PSK key */
3427     if ((alg_k & SSL_PSK) && !tls_process_cke_psk_preamble(s, pkt)) {
3428         /* SSLfatal() already called */
3429         goto err;
3430     }
3431 
3432     if (alg_k & SSL_kPSK) {
3433         /* Identity extracted earlier: should be nothing left */
3434         if (PACKET_remaining(pkt) != 0) {
3435             SSLfatal(s, SSL_AD_DECODE_ERROR,
3436                      SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE,
3437                      SSL_R_LENGTH_MISMATCH);
3438             goto err;
3439         }
3440         /* PSK handled by ssl_generate_master_secret */
3441         if (!ssl_generate_master_secret(s, NULL, 0, 0)) {
3442             /* SSLfatal() already called */
3443             goto err;
3444         }
3445     } else if (alg_k & (SSL_kRSA | SSL_kRSAPSK)) {
3446         if (!tls_process_cke_rsa(s, pkt)) {
3447             /* SSLfatal() already called */
3448             goto err;
3449         }
3450     } else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
3451         if (!tls_process_cke_dhe(s, pkt)) {
3452             /* SSLfatal() already called */
3453             goto err;
3454         }
3455     } else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
3456         if (!tls_process_cke_ecdhe(s, pkt)) {
3457             /* SSLfatal() already called */
3458             goto err;
3459         }
3460     } else if (alg_k & SSL_kSRP) {
3461         if (!tls_process_cke_srp(s, pkt)) {
3462             /* SSLfatal() already called */
3463             goto err;
3464         }
3465     } else if (alg_k & SSL_kGOST) {
3466         if (!tls_process_cke_gost(s, pkt)) {
3467             /* SSLfatal() already called */
3468             goto err;
3469         }
3470     } else {
3471         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3472                  SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE,
3473                  SSL_R_UNKNOWN_CIPHER_TYPE);
3474         goto err;
3475     }
3476 
3477     return MSG_PROCESS_CONTINUE_PROCESSING;
3478  err:
3479 #ifndef OPENSSL_NO_PSK
3480     OPENSSL_clear_free(s->s3->tmp.psk, s->s3->tmp.psklen);
3481     s->s3->tmp.psk = NULL;
3482 #endif
3483     return MSG_PROCESS_ERROR;
3484 }
3485 
3486 WORK_STATE tls_post_process_client_key_exchange(SSL *s, WORK_STATE wst)
3487 {
3488 #ifndef OPENSSL_NO_SCTP
3489     if (wst == WORK_MORE_A) {
3490         if (SSL_IS_DTLS(s)) {
3491             unsigned char sctpauthkey[64];
3492             char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
3493             /*
3494              * Add new shared key for SCTP-Auth, will be ignored if no SCTP
3495              * used.
3496              */
3497             memcpy(labelbuffer, DTLS1_SCTP_AUTH_LABEL,
3498                    sizeof(DTLS1_SCTP_AUTH_LABEL));
3499 
3500             if (SSL_export_keying_material(s, sctpauthkey,
3501                                            sizeof(sctpauthkey), labelbuffer,
3502                                            sizeof(labelbuffer), NULL, 0,
3503                                            0) <= 0) {
3504                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3505                          SSL_F_TLS_POST_PROCESS_CLIENT_KEY_EXCHANGE,
3506                          ERR_R_INTERNAL_ERROR);
3507                 return WORK_ERROR;
3508             }
3509 
3510             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
3511                      sizeof(sctpauthkey), sctpauthkey);
3512         }
3513     }
3514 #endif
3515 
3516     if (s->statem.no_cert_verify || !s->session->peer) {
3517         /*
3518          * No certificate verify or no peer certificate so we no longer need
3519          * the handshake_buffer
3520          */
3521         if (!ssl3_digest_cached_records(s, 0)) {
3522             /* SSLfatal() already called */
3523             return WORK_ERROR;
3524         }
3525         return WORK_FINISHED_CONTINUE;
3526     } else {
3527         if (!s->s3->handshake_buffer) {
3528             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3529                      SSL_F_TLS_POST_PROCESS_CLIENT_KEY_EXCHANGE,
3530                      ERR_R_INTERNAL_ERROR);
3531             return WORK_ERROR;
3532         }
3533         /*
3534          * For sigalgs freeze the handshake buffer. If we support
3535          * extms we've done this already so this is a no-op
3536          */
3537         if (!ssl3_digest_cached_records(s, 1)) {
3538             /* SSLfatal() already called */
3539             return WORK_ERROR;
3540         }
3541     }
3542 
3543     return WORK_FINISHED_CONTINUE;
3544 }
3545 
3546 MSG_PROCESS_RETURN tls_process_client_certificate(SSL *s, PACKET *pkt)
3547 {
3548     int i;
3549     MSG_PROCESS_RETURN ret = MSG_PROCESS_ERROR;
3550     X509 *x = NULL;
3551     unsigned long l;
3552     const unsigned char *certstart, *certbytes;
3553     STACK_OF(X509) *sk = NULL;
3554     PACKET spkt, context;
3555     size_t chainidx;
3556     SSL_SESSION *new_sess = NULL;
3557 
3558     /*
3559      * To get this far we must have read encrypted data from the client. We no
3560      * longer tolerate unencrypted alerts. This value is ignored if less than
3561      * TLSv1.3
3562      */
3563     s->statem.enc_read_state = ENC_READ_STATE_VALID;
3564 
3565     if ((sk = sk_X509_new_null()) == NULL) {
3566         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3567                  ERR_R_MALLOC_FAILURE);
3568         goto err;
3569     }
3570 
3571     if (SSL_IS_TLS13(s) && (!PACKET_get_length_prefixed_1(pkt, &context)
3572                             || (s->pha_context == NULL && PACKET_remaining(&context) != 0)
3573                             || (s->pha_context != NULL &&
3574                                 !PACKET_equal(&context, s->pha_context, s->pha_context_len)))) {
3575         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3576                  SSL_R_INVALID_CONTEXT);
3577         goto err;
3578     }
3579 
3580     if (!PACKET_get_length_prefixed_3(pkt, &spkt)
3581             || PACKET_remaining(pkt) != 0) {
3582         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3583                  SSL_R_LENGTH_MISMATCH);
3584         goto err;
3585     }
3586 
3587     for (chainidx = 0; PACKET_remaining(&spkt) > 0; chainidx++) {
3588         if (!PACKET_get_net_3(&spkt, &l)
3589             || !PACKET_get_bytes(&spkt, &certbytes, l)) {
3590             SSLfatal(s, SSL_AD_DECODE_ERROR,
3591                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3592                      SSL_R_CERT_LENGTH_MISMATCH);
3593             goto err;
3594         }
3595 
3596         certstart = certbytes;
3597         x = d2i_X509(NULL, (const unsigned char **)&certbytes, l);
3598         if (x == NULL) {
3599             SSLfatal(s, SSL_AD_DECODE_ERROR,
3600                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE, ERR_R_ASN1_LIB);
3601             goto err;
3602         }
3603         if (certbytes != (certstart + l)) {
3604             SSLfatal(s, SSL_AD_DECODE_ERROR,
3605                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3606                      SSL_R_CERT_LENGTH_MISMATCH);
3607             goto err;
3608         }
3609 
3610         if (SSL_IS_TLS13(s)) {
3611             RAW_EXTENSION *rawexts = NULL;
3612             PACKET extensions;
3613 
3614             if (!PACKET_get_length_prefixed_2(&spkt, &extensions)) {
3615                 SSLfatal(s, SSL_AD_DECODE_ERROR,
3616                          SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3617                          SSL_R_BAD_LENGTH);
3618                 goto err;
3619             }
3620             if (!tls_collect_extensions(s, &extensions,
3621                                         SSL_EXT_TLS1_3_CERTIFICATE, &rawexts,
3622                                         NULL, chainidx == 0)
3623                 || !tls_parse_all_extensions(s, SSL_EXT_TLS1_3_CERTIFICATE,
3624                                              rawexts, x, chainidx,
3625                                              PACKET_remaining(&spkt) == 0)) {
3626                 OPENSSL_free(rawexts);
3627                 goto err;
3628             }
3629             OPENSSL_free(rawexts);
3630         }
3631 
3632         if (!sk_X509_push(sk, x)) {
3633             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3634                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3635                      ERR_R_MALLOC_FAILURE);
3636             goto err;
3637         }
3638         x = NULL;
3639     }
3640 
3641     if (sk_X509_num(sk) <= 0) {
3642         /* TLS does not mind 0 certs returned */
3643         if (s->version == SSL3_VERSION) {
3644             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
3645                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3646                      SSL_R_NO_CERTIFICATES_RETURNED);
3647             goto err;
3648         }
3649         /* Fail for TLS only if we required a certificate */
3650         else if ((s->verify_mode & SSL_VERIFY_PEER) &&
3651                  (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
3652             SSLfatal(s, SSL_AD_CERTIFICATE_REQUIRED,
3653                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3654                      SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
3655             goto err;
3656         }
3657         /* No client certificate so digest cached records */
3658         if (s->s3->handshake_buffer && !ssl3_digest_cached_records(s, 0)) {
3659             /* SSLfatal() already called */
3660             goto err;
3661         }
3662     } else {
3663         EVP_PKEY *pkey;
3664         i = ssl_verify_cert_chain(s, sk);
3665         if (i <= 0) {
3666             SSLfatal(s, ssl_x509err2alert(s->verify_result),
3667                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3668                      SSL_R_CERTIFICATE_VERIFY_FAILED);
3669             goto err;
3670         }
3671         if (i > 1) {
3672             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
3673                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE, i);
3674             goto err;
3675         }
3676         pkey = X509_get0_pubkey(sk_X509_value(sk, 0));
3677         if (pkey == NULL) {
3678             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
3679                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3680                      SSL_R_UNKNOWN_CERTIFICATE_TYPE);
3681             goto err;
3682         }
3683     }
3684 
3685     /*
3686      * Sessions must be immutable once they go into the session cache. Otherwise
3687      * we can get multi-thread problems. Therefore we don't "update" sessions,
3688      * we replace them with a duplicate. Here, we need to do this every time
3689      * a new certificate is received via post-handshake authentication, as the
3690      * session may have already gone into the session cache.
3691      */
3692 
3693     if (s->post_handshake_auth == SSL_PHA_REQUESTED) {
3694         if ((new_sess = ssl_session_dup(s->session, 0)) == 0) {
3695             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3696                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3697                      ERR_R_MALLOC_FAILURE);
3698             goto err;
3699         }
3700 
3701         SSL_SESSION_free(s->session);
3702         s->session = new_sess;
3703     }
3704 
3705     X509_free(s->session->peer);
3706     s->session->peer = sk_X509_shift(sk);
3707     s->session->verify_result = s->verify_result;
3708 
3709     sk_X509_pop_free(s->session->peer_chain, X509_free);
3710     s->session->peer_chain = sk;
3711 
3712     /*
3713      * Freeze the handshake buffer. For <TLS1.3 we do this after the CKE
3714      * message
3715      */
3716     if (SSL_IS_TLS13(s) && !ssl3_digest_cached_records(s, 1)) {
3717         /* SSLfatal() already called */
3718         goto err;
3719     }
3720 
3721     /*
3722      * Inconsistency alert: cert_chain does *not* include the peer's own
3723      * certificate, while we do include it in statem_clnt.c
3724      */
3725     sk = NULL;
3726 
3727     /* Save the current hash state for when we receive the CertificateVerify */
3728     if (SSL_IS_TLS13(s)) {
3729         if (!ssl_handshake_hash(s, s->cert_verify_hash,
3730                                 sizeof(s->cert_verify_hash),
3731                                 &s->cert_verify_hash_len)) {
3732             /* SSLfatal() already called */
3733             goto err;
3734         }
3735 
3736         /* Resend session tickets */
3737         s->sent_tickets = 0;
3738     }
3739 
3740     ret = MSG_PROCESS_CONTINUE_READING;
3741 
3742  err:
3743     X509_free(x);
3744     sk_X509_pop_free(sk, X509_free);
3745     return ret;
3746 }
3747 
3748 int tls_construct_server_certificate(SSL *s, WPACKET *pkt)
3749 {
3750     CERT_PKEY *cpk = s->s3->tmp.cert;
3751 
3752     if (cpk == NULL) {
3753         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3754                  SSL_F_TLS_CONSTRUCT_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
3755         return 0;
3756     }
3757 
3758     /*
3759      * In TLSv1.3 the certificate chain is always preceded by a 0 length context
3760      * for the server Certificate message
3761      */
3762     if (SSL_IS_TLS13(s) && !WPACKET_put_bytes_u8(pkt, 0)) {
3763         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3764                  SSL_F_TLS_CONSTRUCT_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
3765         return 0;
3766     }
3767     if (!ssl3_output_cert_chain(s, pkt, cpk)) {
3768         /* SSLfatal() already called */
3769         return 0;
3770     }
3771 
3772     return 1;
3773 }
3774 
3775 static int create_ticket_prequel(SSL *s, WPACKET *pkt, uint32_t age_add,
3776                                  unsigned char *tick_nonce)
3777 {
3778     /*
3779      * Ticket lifetime hint: For TLSv1.2 this is advisory only and we leave this
3780      * unspecified for resumed session (for simplicity).
3781      * In TLSv1.3 we reset the "time" field above, and always specify the
3782      * timeout.
3783      */
3784     if (!WPACKET_put_bytes_u32(pkt,
3785                                (s->hit && !SSL_IS_TLS13(s))
3786                                ? 0 : s->session->timeout)) {
3787         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CREATE_TICKET_PREQUEL,
3788                  ERR_R_INTERNAL_ERROR);
3789         return 0;
3790     }
3791 
3792     if (SSL_IS_TLS13(s)) {
3793         if (!WPACKET_put_bytes_u32(pkt, age_add)
3794                 || !WPACKET_sub_memcpy_u8(pkt, tick_nonce, TICKET_NONCE_SIZE)) {
3795             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CREATE_TICKET_PREQUEL,
3796                      ERR_R_INTERNAL_ERROR);
3797             return 0;
3798         }
3799     }
3800 
3801     /* Start the sub-packet for the actual ticket data */
3802     if (!WPACKET_start_sub_packet_u16(pkt)) {
3803         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CREATE_TICKET_PREQUEL,
3804                  ERR_R_INTERNAL_ERROR);
3805         return 0;
3806     }
3807 
3808     return 1;
3809 }
3810 
3811 static int construct_stateless_ticket(SSL *s, WPACKET *pkt, uint32_t age_add,
3812                                       unsigned char *tick_nonce)
3813 {
3814     unsigned char *senc = NULL;
3815     EVP_CIPHER_CTX *ctx = NULL;
3816     HMAC_CTX *hctx = NULL;
3817     unsigned char *p, *encdata1, *encdata2, *macdata1, *macdata2;
3818     const unsigned char *const_p;
3819     int len, slen_full, slen, lenfinal;
3820     SSL_SESSION *sess;
3821     unsigned int hlen;
3822     SSL_CTX *tctx = s->session_ctx;
3823     unsigned char iv[EVP_MAX_IV_LENGTH];
3824     unsigned char key_name[TLSEXT_KEYNAME_LENGTH];
3825     int iv_len, ok = 0;
3826     size_t macoffset, macendoffset;
3827 
3828     /* get session encoding length */
3829     slen_full = i2d_SSL_SESSION(s->session, NULL);
3830     /*
3831      * Some length values are 16 bits, so forget it if session is too
3832      * long
3833      */
3834     if (slen_full == 0 || slen_full > 0xFF00) {
3835         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3836                  ERR_R_INTERNAL_ERROR);
3837         goto err;
3838     }
3839     senc = OPENSSL_malloc(slen_full);
3840     if (senc == NULL) {
3841         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3842                  SSL_F_CONSTRUCT_STATELESS_TICKET, ERR_R_MALLOC_FAILURE);
3843         goto err;
3844     }
3845 
3846     ctx = EVP_CIPHER_CTX_new();
3847     hctx = HMAC_CTX_new();
3848     if (ctx == NULL || hctx == NULL) {
3849         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3850                  ERR_R_MALLOC_FAILURE);
3851         goto err;
3852     }
3853 
3854     p = senc;
3855     if (!i2d_SSL_SESSION(s->session, &p)) {
3856         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3857                  ERR_R_INTERNAL_ERROR);
3858         goto err;
3859     }
3860 
3861     /*
3862      * create a fresh copy (not shared with other threads) to clean up
3863      */
3864     const_p = senc;
3865     sess = d2i_SSL_SESSION(NULL, &const_p, slen_full);
3866     if (sess == NULL) {
3867         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3868                  ERR_R_INTERNAL_ERROR);
3869         goto err;
3870     }
3871 
3872     slen = i2d_SSL_SESSION(sess, NULL);
3873     if (slen == 0 || slen > slen_full) {
3874         /* shouldn't ever happen */
3875         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3876                  ERR_R_INTERNAL_ERROR);
3877         SSL_SESSION_free(sess);
3878         goto err;
3879     }
3880     p = senc;
3881     if (!i2d_SSL_SESSION(sess, &p)) {
3882         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3883                  ERR_R_INTERNAL_ERROR);
3884         SSL_SESSION_free(sess);
3885         goto err;
3886     }
3887     SSL_SESSION_free(sess);
3888 
3889     /*
3890      * Initialize HMAC and cipher contexts. If callback present it does
3891      * all the work otherwise use generated values from parent ctx.
3892      */
3893     if (tctx->ext.ticket_key_cb) {
3894         /* if 0 is returned, write an empty ticket */
3895         int ret = tctx->ext.ticket_key_cb(s, key_name, iv, ctx,
3896                                              hctx, 1);
3897 
3898         if (ret == 0) {
3899 
3900             /* Put timeout and length */
3901             if (!WPACKET_put_bytes_u32(pkt, 0)
3902                     || !WPACKET_put_bytes_u16(pkt, 0)) {
3903                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3904                          SSL_F_CONSTRUCT_STATELESS_TICKET,
3905                          ERR_R_INTERNAL_ERROR);
3906                 goto err;
3907             }
3908             OPENSSL_free(senc);
3909             EVP_CIPHER_CTX_free(ctx);
3910             HMAC_CTX_free(hctx);
3911             return 1;
3912         }
3913         if (ret < 0) {
3914             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3915                      SSL_R_CALLBACK_FAILED);
3916             goto err;
3917         }
3918         iv_len = EVP_CIPHER_CTX_iv_length(ctx);
3919     } else {
3920         const EVP_CIPHER *cipher = EVP_aes_256_cbc();
3921 
3922         iv_len = EVP_CIPHER_iv_length(cipher);
3923         if (RAND_bytes(iv, iv_len) <= 0
3924                 || !EVP_EncryptInit_ex(ctx, cipher, NULL,
3925                                        tctx->ext.secure->tick_aes_key, iv)
3926                 || !HMAC_Init_ex(hctx, tctx->ext.secure->tick_hmac_key,
3927                                  sizeof(tctx->ext.secure->tick_hmac_key),
3928                                  EVP_sha256(), NULL)) {
3929             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3930                      ERR_R_INTERNAL_ERROR);
3931             goto err;
3932         }
3933         memcpy(key_name, tctx->ext.tick_key_name,
3934                sizeof(tctx->ext.tick_key_name));
3935     }
3936 
3937     if (!create_ticket_prequel(s, pkt, age_add, tick_nonce)) {
3938         /* SSLfatal() already called */
3939         goto err;
3940     }
3941 
3942     if (!WPACKET_get_total_written(pkt, &macoffset)
3943                /* Output key name */
3944             || !WPACKET_memcpy(pkt, key_name, sizeof(key_name))
3945                /* output IV */
3946             || !WPACKET_memcpy(pkt, iv, iv_len)
3947             || !WPACKET_reserve_bytes(pkt, slen + EVP_MAX_BLOCK_LENGTH,
3948                                       &encdata1)
3949                /* Encrypt session data */
3950             || !EVP_EncryptUpdate(ctx, encdata1, &len, senc, slen)
3951             || !WPACKET_allocate_bytes(pkt, len, &encdata2)
3952             || encdata1 != encdata2
3953             || !EVP_EncryptFinal(ctx, encdata1 + len, &lenfinal)
3954             || !WPACKET_allocate_bytes(pkt, lenfinal, &encdata2)
3955             || encdata1 + len != encdata2
3956             || len + lenfinal > slen + EVP_MAX_BLOCK_LENGTH
3957             || !WPACKET_get_total_written(pkt, &macendoffset)
3958             || !HMAC_Update(hctx,
3959                             (unsigned char *)s->init_buf->data + macoffset,
3960                             macendoffset - macoffset)
3961             || !WPACKET_reserve_bytes(pkt, EVP_MAX_MD_SIZE, &macdata1)
3962             || !HMAC_Final(hctx, macdata1, &hlen)
3963             || hlen > EVP_MAX_MD_SIZE
3964             || !WPACKET_allocate_bytes(pkt, hlen, &macdata2)
3965             || macdata1 != macdata2) {
3966         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3967                  SSL_F_CONSTRUCT_STATELESS_TICKET, ERR_R_INTERNAL_ERROR);
3968         goto err;
3969     }
3970 
3971     /* Close the sub-packet created by create_ticket_prequel() */
3972     if (!WPACKET_close(pkt)) {
3973         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3974                  ERR_R_INTERNAL_ERROR);
3975         goto err;
3976     }
3977 
3978     ok = 1;
3979  err:
3980     OPENSSL_free(senc);
3981     EVP_CIPHER_CTX_free(ctx);
3982     HMAC_CTX_free(hctx);
3983     return ok;
3984 }
3985 
3986 static int construct_stateful_ticket(SSL *s, WPACKET *pkt, uint32_t age_add,
3987                                      unsigned char *tick_nonce)
3988 {
3989     if (!create_ticket_prequel(s, pkt, age_add, tick_nonce)) {
3990         /* SSLfatal() already called */
3991         return 0;
3992     }
3993 
3994     if (!WPACKET_memcpy(pkt, s->session->session_id,
3995                         s->session->session_id_length)
3996             || !WPACKET_close(pkt)) {
3997         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATEFUL_TICKET,
3998                  ERR_R_INTERNAL_ERROR);
3999         return 0;
4000     }
4001 
4002     return 1;
4003 }
4004 
4005 int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt)
4006 {
4007     SSL_CTX *tctx = s->session_ctx;
4008     unsigned char tick_nonce[TICKET_NONCE_SIZE];
4009     union {
4010         unsigned char age_add_c[sizeof(uint32_t)];
4011         uint32_t age_add;
4012     } age_add_u;
4013 
4014     age_add_u.age_add = 0;
4015 
4016     if (SSL_IS_TLS13(s)) {
4017         size_t i, hashlen;
4018         uint64_t nonce;
4019         static const unsigned char nonce_label[] = "resumption";
4020         const EVP_MD *md = ssl_handshake_md(s);
4021         void (*cb) (const SSL *ssl, int type, int val) = NULL;
4022         int hashleni = EVP_MD_size(md);
4023 
4024         /* Ensure cast to size_t is safe */
4025         if (!ossl_assert(hashleni >= 0)) {
4026             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4027                      SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4028                      ERR_R_INTERNAL_ERROR);
4029             goto err;
4030         }
4031         hashlen = (size_t)hashleni;
4032 
4033         if (s->info_callback != NULL)
4034             cb = s->info_callback;
4035         else if (s->ctx->info_callback != NULL)
4036             cb = s->ctx->info_callback;
4037 
4038         if (cb != NULL) {
4039             /*
4040              * We don't start and stop the handshake in between each ticket when
4041              * sending more than one - but it should appear that way to the info
4042              * callback.
4043              */
4044             if (s->sent_tickets != 0) {
4045                 ossl_statem_set_in_init(s, 0);
4046                 cb(s, SSL_CB_HANDSHAKE_DONE, 1);
4047                 ossl_statem_set_in_init(s, 1);
4048             }
4049             cb(s, SSL_CB_HANDSHAKE_START, 1);
4050         }
4051         /*
4052          * If we already sent one NewSessionTicket, or we resumed then
4053          * s->session may already be in a cache and so we must not modify it.
4054          * Instead we need to take a copy of it and modify that.
4055          */
4056         if (s->sent_tickets != 0 || s->hit) {
4057             SSL_SESSION *new_sess = ssl_session_dup(s->session, 0);
4058 
4059             if (new_sess == NULL) {
4060                 /* SSLfatal already called */
4061                 goto err;
4062             }
4063 
4064             SSL_SESSION_free(s->session);
4065             s->session = new_sess;
4066         }
4067 
4068         if (!ssl_generate_session_id(s, s->session)) {
4069             /* SSLfatal() already called */
4070             goto err;
4071         }
4072         if (RAND_bytes(age_add_u.age_add_c, sizeof(age_add_u)) <= 0) {
4073             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4074                      SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4075                      ERR_R_INTERNAL_ERROR);
4076             goto err;
4077         }
4078         s->session->ext.tick_age_add = age_add_u.age_add;
4079 
4080         nonce = s->next_ticket_nonce;
4081         for (i = TICKET_NONCE_SIZE; i > 0; i--) {
4082             tick_nonce[i - 1] = (unsigned char)(nonce & 0xff);
4083             nonce >>= 8;
4084         }
4085 
4086         if (!tls13_hkdf_expand(s, md, s->resumption_master_secret,
4087                                nonce_label,
4088                                sizeof(nonce_label) - 1,
4089                                tick_nonce,
4090                                TICKET_NONCE_SIZE,
4091                                s->session->master_key,
4092                                hashlen)) {
4093             /* SSLfatal() already called */
4094             goto err;
4095         }
4096         s->session->master_key_length = hashlen;
4097 
4098         s->session->time = (long)time(NULL);
4099         if (s->s3->alpn_selected != NULL) {
4100             OPENSSL_free(s->session->ext.alpn_selected);
4101             s->session->ext.alpn_selected =
4102                 OPENSSL_memdup(s->s3->alpn_selected, s->s3->alpn_selected_len);
4103             if (s->session->ext.alpn_selected == NULL) {
4104                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4105                          SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4106                          ERR_R_MALLOC_FAILURE);
4107                 goto err;
4108             }
4109             s->session->ext.alpn_selected_len = s->s3->alpn_selected_len;
4110         }
4111         s->session->ext.max_early_data = s->max_early_data;
4112     }
4113 
4114     if (tctx->generate_ticket_cb != NULL &&
4115         tctx->generate_ticket_cb(s, tctx->ticket_cb_data) == 0)
4116         goto err;
4117 
4118     /*
4119      * If we are using anti-replay protection then we behave as if
4120      * SSL_OP_NO_TICKET is set - we are caching tickets anyway so there
4121      * is no point in using full stateless tickets.
4122      */
4123     if (SSL_IS_TLS13(s)
4124             && ((s->options & SSL_OP_NO_TICKET) != 0
4125                 || (s->max_early_data > 0
4126                     && (s->options & SSL_OP_NO_ANTI_REPLAY) == 0))) {
4127         if (!construct_stateful_ticket(s, pkt, age_add_u.age_add, tick_nonce)) {
4128             /* SSLfatal() already called */
4129             goto err;
4130         }
4131     } else if (!construct_stateless_ticket(s, pkt, age_add_u.age_add,
4132                                            tick_nonce)) {
4133         /* SSLfatal() already called */
4134         goto err;
4135     }
4136 
4137     if (SSL_IS_TLS13(s)) {
4138         if (!tls_construct_extensions(s, pkt,
4139                                       SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
4140                                       NULL, 0)) {
4141             /* SSLfatal() already called */
4142             goto err;
4143         }
4144         /*
4145          * Increment both |sent_tickets| and |next_ticket_nonce|. |sent_tickets|
4146          * gets reset to 0 if we send more tickets following a post-handshake
4147          * auth, but |next_ticket_nonce| does not.
4148          */
4149         s->sent_tickets++;
4150         s->next_ticket_nonce++;
4151         ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
4152     }
4153 
4154     return 1;
4155  err:
4156     return 0;
4157 }
4158 
4159 /*
4160  * In TLSv1.3 this is called from the extensions code, otherwise it is used to
4161  * create a separate message. Returns 1 on success or 0 on failure.
4162  */
4163 int tls_construct_cert_status_body(SSL *s, WPACKET *pkt)
4164 {
4165     if (!WPACKET_put_bytes_u8(pkt, s->ext.status_type)
4166             || !WPACKET_sub_memcpy_u24(pkt, s->ext.ocsp.resp,
4167                                        s->ext.ocsp.resp_len)) {
4168         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CERT_STATUS_BODY,
4169                  ERR_R_INTERNAL_ERROR);
4170         return 0;
4171     }
4172 
4173     return 1;
4174 }
4175 
4176 int tls_construct_cert_status(SSL *s, WPACKET *pkt)
4177 {
4178     if (!tls_construct_cert_status_body(s, pkt)) {
4179         /* SSLfatal() already called */
4180         return 0;
4181     }
4182 
4183     return 1;
4184 }
4185 
4186 #ifndef OPENSSL_NO_NEXTPROTONEG
4187 /*
4188  * tls_process_next_proto reads a Next Protocol Negotiation handshake message.
4189  * It sets the next_proto member in s if found
4190  */
4191 MSG_PROCESS_RETURN tls_process_next_proto(SSL *s, PACKET *pkt)
4192 {
4193     PACKET next_proto, padding;
4194     size_t next_proto_len;
4195 
4196     /*-
4197      * The payload looks like:
4198      *   uint8 proto_len;
4199      *   uint8 proto[proto_len];
4200      *   uint8 padding_len;
4201      *   uint8 padding[padding_len];
4202      */
4203     if (!PACKET_get_length_prefixed_1(pkt, &next_proto)
4204         || !PACKET_get_length_prefixed_1(pkt, &padding)
4205         || PACKET_remaining(pkt) > 0) {
4206         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_NEXT_PROTO,
4207                  SSL_R_LENGTH_MISMATCH);
4208         return MSG_PROCESS_ERROR;
4209     }
4210 
4211     if (!PACKET_memdup(&next_proto, &s->ext.npn, &next_proto_len)) {
4212         s->ext.npn_len = 0;
4213         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_NEXT_PROTO,
4214                  ERR_R_INTERNAL_ERROR);
4215         return MSG_PROCESS_ERROR;
4216     }
4217 
4218     s->ext.npn_len = (unsigned char)next_proto_len;
4219 
4220     return MSG_PROCESS_CONTINUE_READING;
4221 }
4222 #endif
4223 
4224 static int tls_construct_encrypted_extensions(SSL *s, WPACKET *pkt)
4225 {
4226     if (!tls_construct_extensions(s, pkt, SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
4227                                   NULL, 0)) {
4228         /* SSLfatal() already called */
4229         return 0;
4230     }
4231 
4232     return 1;
4233 }
4234 
4235 MSG_PROCESS_RETURN tls_process_end_of_early_data(SSL *s, PACKET *pkt)
4236 {
4237     if (PACKET_remaining(pkt) != 0) {
4238         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_END_OF_EARLY_DATA,
4239                  SSL_R_LENGTH_MISMATCH);
4240         return MSG_PROCESS_ERROR;
4241     }
4242 
4243     if (s->early_data_state != SSL_EARLY_DATA_READING
4244             && s->early_data_state != SSL_EARLY_DATA_READ_RETRY) {
4245         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_END_OF_EARLY_DATA,
4246                  ERR_R_INTERNAL_ERROR);
4247         return MSG_PROCESS_ERROR;
4248     }
4249 
4250     /*
4251      * EndOfEarlyData signals a key change so the end of the message must be on
4252      * a record boundary.
4253      */
4254     if (RECORD_LAYER_processed_read_pending(&s->rlayer)) {
4255         SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
4256                  SSL_F_TLS_PROCESS_END_OF_EARLY_DATA,
4257                  SSL_R_NOT_ON_RECORD_BOUNDARY);
4258         return MSG_PROCESS_ERROR;
4259     }
4260 
4261     s->early_data_state = SSL_EARLY_DATA_FINISHED_READING;
4262     if (!s->method->ssl3_enc->change_cipher_state(s,
4263                 SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_SERVER_READ)) {
4264         /* SSLfatal() already called */
4265         return MSG_PROCESS_ERROR;
4266     }
4267 
4268     return MSG_PROCESS_CONTINUE_READING;
4269 }
4270