xref: /freebsd/crypto/openssl/ssl/statem/statem_srvr.c (revision 8b959dd6a3921c35395bef4a6d7ad2426a3bd88e)
1 /*
2  * Copyright 1995-2021 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_local.h"
14 #include "statem_local.h"
15 #include "internal/constant_time.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 #include <openssl/asn1t.h>
27 
28 #define TICKET_NONCE_SIZE       8
29 
30 typedef struct {
31   ASN1_TYPE *kxBlob;
32   ASN1_TYPE *opaqueBlob;
33 } GOST_KX_MESSAGE;
34 
35 DECLARE_ASN1_FUNCTIONS(GOST_KX_MESSAGE)
36 
37 ASN1_SEQUENCE(GOST_KX_MESSAGE) = {
38   ASN1_SIMPLE(GOST_KX_MESSAGE,  kxBlob, ASN1_ANY),
39   ASN1_OPT(GOST_KX_MESSAGE, opaqueBlob, ASN1_ANY),
40 } ASN1_SEQUENCE_END(GOST_KX_MESSAGE)
41 
42 IMPLEMENT_ASN1_FUNCTIONS(GOST_KX_MESSAGE)
43 
44 static int tls_construct_encrypted_extensions(SSL *s, WPACKET *pkt);
45 
46 /*
47  * ossl_statem_server13_read_transition() encapsulates the logic for the allowed
48  * handshake state transitions when a TLSv1.3 server is reading messages from
49  * the client. The message type that the client has sent is provided in |mt|.
50  * The current state is in |s->statem.hand_state|.
51  *
52  * Return values are 1 for success (transition allowed) and  0 on error
53  * (transition not allowed)
54  */
55 static int ossl_statem_server13_read_transition(SSL *s, int mt)
56 {
57     OSSL_STATEM *st = &s->statem;
58 
59     /*
60      * Note: There is no case for TLS_ST_BEFORE because at that stage we have
61      * not negotiated TLSv1.3 yet, so that case is handled by
62      * ossl_statem_server_read_transition()
63      */
64     switch (st->hand_state) {
65     default:
66         break;
67 
68     case TLS_ST_EARLY_DATA:
69         if (s->hello_retry_request == SSL_HRR_PENDING) {
70             if (mt == SSL3_MT_CLIENT_HELLO) {
71                 st->hand_state = TLS_ST_SR_CLNT_HELLO;
72                 return 1;
73             }
74             break;
75         } else if (s->ext.early_data == SSL_EARLY_DATA_ACCEPTED) {
76             if (mt == SSL3_MT_END_OF_EARLY_DATA) {
77                 st->hand_state = TLS_ST_SR_END_OF_EARLY_DATA;
78                 return 1;
79             }
80             break;
81         }
82         /* Fall through */
83 
84     case TLS_ST_SR_END_OF_EARLY_DATA:
85     case TLS_ST_SW_FINISHED:
86         if (s->s3->tmp.cert_request) {
87             if (mt == SSL3_MT_CERTIFICATE) {
88                 st->hand_state = TLS_ST_SR_CERT;
89                 return 1;
90             }
91         } else {
92             if (mt == SSL3_MT_FINISHED) {
93                 st->hand_state = TLS_ST_SR_FINISHED;
94                 return 1;
95             }
96         }
97         break;
98 
99     case TLS_ST_SR_CERT:
100         if (s->session->peer == NULL) {
101             if (mt == SSL3_MT_FINISHED) {
102                 st->hand_state = TLS_ST_SR_FINISHED;
103                 return 1;
104             }
105         } else {
106             if (mt == SSL3_MT_CERTIFICATE_VERIFY) {
107                 st->hand_state = TLS_ST_SR_CERT_VRFY;
108                 return 1;
109             }
110         }
111         break;
112 
113     case TLS_ST_SR_CERT_VRFY:
114         if (mt == SSL3_MT_FINISHED) {
115             st->hand_state = TLS_ST_SR_FINISHED;
116             return 1;
117         }
118         break;
119 
120     case TLS_ST_OK:
121         /*
122          * Its never ok to start processing handshake messages in the middle of
123          * early data (i.e. before we've received the end of early data alert)
124          */
125         if (s->early_data_state == SSL_EARLY_DATA_READING)
126             break;
127 
128         if (mt == SSL3_MT_CERTIFICATE
129                 && s->post_handshake_auth == SSL_PHA_REQUESTED) {
130             st->hand_state = TLS_ST_SR_CERT;
131             return 1;
132         }
133 
134         if (mt == SSL3_MT_KEY_UPDATE) {
135             st->hand_state = TLS_ST_SR_KEY_UPDATE;
136             return 1;
137         }
138         break;
139     }
140 
141     /* No valid transition found */
142     return 0;
143 }
144 
145 /*
146  * ossl_statem_server_read_transition() encapsulates the logic for the allowed
147  * handshake state transitions when the server is reading messages from the
148  * client. The message type that the client has sent is provided in |mt|. The
149  * current state is in |s->statem.hand_state|.
150  *
151  * Return values are 1 for success (transition allowed) and  0 on error
152  * (transition not allowed)
153  */
154 int ossl_statem_server_read_transition(SSL *s, int mt)
155 {
156     OSSL_STATEM *st = &s->statem;
157 
158     if (SSL_IS_TLS13(s)) {
159         if (!ossl_statem_server13_read_transition(s, mt))
160             goto err;
161         return 1;
162     }
163 
164     switch (st->hand_state) {
165     default:
166         break;
167 
168     case TLS_ST_BEFORE:
169     case TLS_ST_OK:
170     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
171         if (mt == SSL3_MT_CLIENT_HELLO) {
172             st->hand_state = TLS_ST_SR_CLNT_HELLO;
173             return 1;
174         }
175         break;
176 
177     case TLS_ST_SW_SRVR_DONE:
178         /*
179          * If we get a CKE message after a ServerDone then either
180          * 1) We didn't request a Certificate
181          * OR
182          * 2) If we did request one then
183          *      a) We allow no Certificate to be returned
184          *      AND
185          *      b) We are running SSL3 (in TLS1.0+ the client must return a 0
186          *         list if we requested a certificate)
187          */
188         if (mt == SSL3_MT_CLIENT_KEY_EXCHANGE) {
189             if (s->s3->tmp.cert_request) {
190                 if (s->version == SSL3_VERSION) {
191                     if ((s->verify_mode & SSL_VERIFY_PEER)
192                         && (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
193                         /*
194                          * This isn't an unexpected message as such - we're just
195                          * not going to accept it because we require a client
196                          * cert.
197                          */
198                         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
199                                  SSL_F_OSSL_STATEM_SERVER_READ_TRANSITION,
200                                  SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
201                         return 0;
202                     }
203                     st->hand_state = TLS_ST_SR_KEY_EXCH;
204                     return 1;
205                 }
206             } else {
207                 st->hand_state = TLS_ST_SR_KEY_EXCH;
208                 return 1;
209             }
210         } else if (s->s3->tmp.cert_request) {
211             if (mt == SSL3_MT_CERTIFICATE) {
212                 st->hand_state = TLS_ST_SR_CERT;
213                 return 1;
214             }
215         }
216         break;
217 
218     case TLS_ST_SR_CERT:
219         if (mt == SSL3_MT_CLIENT_KEY_EXCHANGE) {
220             st->hand_state = TLS_ST_SR_KEY_EXCH;
221             return 1;
222         }
223         break;
224 
225     case TLS_ST_SR_KEY_EXCH:
226         /*
227          * We should only process a CertificateVerify message if we have
228          * received a Certificate from the client. If so then |s->session->peer|
229          * will be non NULL. In some instances a CertificateVerify message is
230          * not required even if the peer has sent a Certificate (e.g. such as in
231          * the case of static DH). In that case |st->no_cert_verify| should be
232          * set.
233          */
234         if (s->session->peer == NULL || st->no_cert_verify) {
235             if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
236                 /*
237                  * For the ECDH ciphersuites when the client sends its ECDH
238                  * pub key in a certificate, the CertificateVerify message is
239                  * not sent. Also for GOST ciphersuites when the client uses
240                  * its key from the certificate for key exchange.
241                  */
242                 st->hand_state = TLS_ST_SR_CHANGE;
243                 return 1;
244             }
245         } else {
246             if (mt == SSL3_MT_CERTIFICATE_VERIFY) {
247                 st->hand_state = TLS_ST_SR_CERT_VRFY;
248                 return 1;
249             }
250         }
251         break;
252 
253     case TLS_ST_SR_CERT_VRFY:
254         if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
255             st->hand_state = TLS_ST_SR_CHANGE;
256             return 1;
257         }
258         break;
259 
260     case TLS_ST_SR_CHANGE:
261 #ifndef OPENSSL_NO_NEXTPROTONEG
262         if (s->s3->npn_seen) {
263             if (mt == SSL3_MT_NEXT_PROTO) {
264                 st->hand_state = TLS_ST_SR_NEXT_PROTO;
265                 return 1;
266             }
267         } else {
268 #endif
269             if (mt == SSL3_MT_FINISHED) {
270                 st->hand_state = TLS_ST_SR_FINISHED;
271                 return 1;
272             }
273 #ifndef OPENSSL_NO_NEXTPROTONEG
274         }
275 #endif
276         break;
277 
278 #ifndef OPENSSL_NO_NEXTPROTONEG
279     case TLS_ST_SR_NEXT_PROTO:
280         if (mt == SSL3_MT_FINISHED) {
281             st->hand_state = TLS_ST_SR_FINISHED;
282             return 1;
283         }
284         break;
285 #endif
286 
287     case TLS_ST_SW_FINISHED:
288         if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
289             st->hand_state = TLS_ST_SR_CHANGE;
290             return 1;
291         }
292         break;
293     }
294 
295  err:
296     /* No valid transition found */
297     if (SSL_IS_DTLS(s) && mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
298         BIO *rbio;
299 
300         /*
301          * CCS messages don't have a message sequence number so this is probably
302          * because of an out-of-order CCS. We'll just drop it.
303          */
304         s->init_num = 0;
305         s->rwstate = SSL_READING;
306         rbio = SSL_get_rbio(s);
307         BIO_clear_retry_flags(rbio);
308         BIO_set_retry_read(rbio);
309         return 0;
310     }
311     SSLfatal(s, SSL3_AD_UNEXPECTED_MESSAGE,
312              SSL_F_OSSL_STATEM_SERVER_READ_TRANSITION,
313              SSL_R_UNEXPECTED_MESSAGE);
314     return 0;
315 }
316 
317 /*
318  * Should we send a ServerKeyExchange message?
319  *
320  * Valid return values are:
321  *   1: Yes
322  *   0: No
323  */
324 static int send_server_key_exchange(SSL *s)
325 {
326     unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
327 
328     /*
329      * only send a ServerKeyExchange if DH or fortezza but we have a
330      * sign only certificate PSK: may send PSK identity hints For
331      * ECC ciphersuites, we send a serverKeyExchange message only if
332      * the cipher suite is either ECDH-anon or ECDHE. In other cases,
333      * the server certificate contains the server's public key for
334      * key exchange.
335      */
336     if (alg_k & (SSL_kDHE | SSL_kECDHE)
337         /*
338          * PSK: send ServerKeyExchange if PSK identity hint if
339          * provided
340          */
341 #ifndef OPENSSL_NO_PSK
342         /* Only send SKE if we have identity hint for plain PSK */
343         || ((alg_k & (SSL_kPSK | SSL_kRSAPSK))
344             && s->cert->psk_identity_hint)
345         /* For other PSK always send SKE */
346         || (alg_k & (SSL_PSK & (SSL_kDHEPSK | SSL_kECDHEPSK)))
347 #endif
348 #ifndef OPENSSL_NO_SRP
349         /* SRP: send ServerKeyExchange */
350         || (alg_k & SSL_kSRP)
351 #endif
352         ) {
353         return 1;
354     }
355 
356     return 0;
357 }
358 
359 /*
360  * Should we send a CertificateRequest message?
361  *
362  * Valid return values are:
363  *   1: Yes
364  *   0: No
365  */
366 int send_certificate_request(SSL *s)
367 {
368     if (
369            /* don't request cert unless asked for it: */
370            s->verify_mode & SSL_VERIFY_PEER
371            /*
372             * don't request if post-handshake-only unless doing
373             * post-handshake in TLSv1.3:
374             */
375            && (!SSL_IS_TLS13(s) || !(s->verify_mode & SSL_VERIFY_POST_HANDSHAKE)
376                || s->post_handshake_auth == SSL_PHA_REQUEST_PENDING)
377            /*
378             * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
379             * a second time:
380             */
381            && (s->certreqs_sent < 1 ||
382                !(s->verify_mode & SSL_VERIFY_CLIENT_ONCE))
383            /*
384             * never request cert in anonymous ciphersuites (see
385             * section "Certificate request" in SSL 3 drafts and in
386             * RFC 2246):
387             */
388            && (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
389                /*
390                 * ... except when the application insists on
391                 * verification (against the specs, but statem_clnt.c accepts
392                 * this for SSL 3)
393                 */
394                || (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
395            /* don't request certificate for SRP auth */
396            && !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aSRP)
397            /*
398             * With normal PSK Certificates and Certificate Requests
399             * are omitted
400             */
401            && !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aPSK)) {
402         return 1;
403     }
404 
405     return 0;
406 }
407 
408 /*
409  * ossl_statem_server13_write_transition() works out what handshake state to
410  * move to next when a TLSv1.3 server is writing messages to be sent to the
411  * client.
412  */
413 static WRITE_TRAN ossl_statem_server13_write_transition(SSL *s)
414 {
415     OSSL_STATEM *st = &s->statem;
416 
417     /*
418      * No case for TLS_ST_BEFORE, because at that stage we have not negotiated
419      * TLSv1.3 yet, so that is handled by ossl_statem_server_write_transition()
420      */
421 
422     switch (st->hand_state) {
423     default:
424         /* Shouldn't happen */
425         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
426                  SSL_F_OSSL_STATEM_SERVER13_WRITE_TRANSITION,
427                  ERR_R_INTERNAL_ERROR);
428         return WRITE_TRAN_ERROR;
429 
430     case TLS_ST_OK:
431         if (s->key_update != SSL_KEY_UPDATE_NONE) {
432             st->hand_state = TLS_ST_SW_KEY_UPDATE;
433             return WRITE_TRAN_CONTINUE;
434         }
435         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
436             st->hand_state = TLS_ST_SW_CERT_REQ;
437             return WRITE_TRAN_CONTINUE;
438         }
439         /* Try to read from the client instead */
440         return WRITE_TRAN_FINISHED;
441 
442     case TLS_ST_SR_CLNT_HELLO:
443         st->hand_state = TLS_ST_SW_SRVR_HELLO;
444         return WRITE_TRAN_CONTINUE;
445 
446     case TLS_ST_SW_SRVR_HELLO:
447         if ((s->options & SSL_OP_ENABLE_MIDDLEBOX_COMPAT) != 0
448                 && s->hello_retry_request != SSL_HRR_COMPLETE)
449             st->hand_state = TLS_ST_SW_CHANGE;
450         else if (s->hello_retry_request == SSL_HRR_PENDING)
451             st->hand_state = TLS_ST_EARLY_DATA;
452         else
453             st->hand_state = TLS_ST_SW_ENCRYPTED_EXTENSIONS;
454         return WRITE_TRAN_CONTINUE;
455 
456     case TLS_ST_SW_CHANGE:
457         if (s->hello_retry_request == SSL_HRR_PENDING)
458             st->hand_state = TLS_ST_EARLY_DATA;
459         else
460             st->hand_state = TLS_ST_SW_ENCRYPTED_EXTENSIONS;
461         return WRITE_TRAN_CONTINUE;
462 
463     case TLS_ST_SW_ENCRYPTED_EXTENSIONS:
464         if (s->hit)
465             st->hand_state = TLS_ST_SW_FINISHED;
466         else if (send_certificate_request(s))
467             st->hand_state = TLS_ST_SW_CERT_REQ;
468         else
469             st->hand_state = TLS_ST_SW_CERT;
470 
471         return WRITE_TRAN_CONTINUE;
472 
473     case TLS_ST_SW_CERT_REQ:
474         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
475             s->post_handshake_auth = SSL_PHA_REQUESTED;
476             st->hand_state = TLS_ST_OK;
477         } else {
478             st->hand_state = TLS_ST_SW_CERT;
479         }
480         return WRITE_TRAN_CONTINUE;
481 
482     case TLS_ST_SW_CERT:
483         st->hand_state = TLS_ST_SW_CERT_VRFY;
484         return WRITE_TRAN_CONTINUE;
485 
486     case TLS_ST_SW_CERT_VRFY:
487         st->hand_state = TLS_ST_SW_FINISHED;
488         return WRITE_TRAN_CONTINUE;
489 
490     case TLS_ST_SW_FINISHED:
491         st->hand_state = TLS_ST_EARLY_DATA;
492         return WRITE_TRAN_CONTINUE;
493 
494     case TLS_ST_EARLY_DATA:
495         return WRITE_TRAN_FINISHED;
496 
497     case TLS_ST_SR_FINISHED:
498         /*
499          * Technically we have finished the handshake at this point, but we're
500          * going to remain "in_init" for now and write out any session tickets
501          * immediately.
502          */
503         if (s->post_handshake_auth == SSL_PHA_REQUESTED) {
504             s->post_handshake_auth = SSL_PHA_EXT_RECEIVED;
505         } else if (!s->ext.ticket_expected) {
506             /*
507              * If we're not going to renew the ticket then we just finish the
508              * handshake at this point.
509              */
510             st->hand_state = TLS_ST_OK;
511             return WRITE_TRAN_CONTINUE;
512         }
513         if (s->num_tickets > s->sent_tickets)
514             st->hand_state = TLS_ST_SW_SESSION_TICKET;
515         else
516             st->hand_state = TLS_ST_OK;
517         return WRITE_TRAN_CONTINUE;
518 
519     case TLS_ST_SR_KEY_UPDATE:
520     case TLS_ST_SW_KEY_UPDATE:
521         st->hand_state = TLS_ST_OK;
522         return WRITE_TRAN_CONTINUE;
523 
524     case TLS_ST_SW_SESSION_TICKET:
525         /* In a resumption we only ever send a maximum of one new ticket.
526          * Following an initial handshake we send the number of tickets we have
527          * been configured for.
528          */
529         if (s->hit || s->num_tickets <= s->sent_tickets) {
530             /* We've written enough tickets out. */
531             st->hand_state = TLS_ST_OK;
532         }
533         return WRITE_TRAN_CONTINUE;
534     }
535 }
536 
537 /*
538  * ossl_statem_server_write_transition() works out what handshake state to move
539  * to next when the server is writing messages to be sent to the client.
540  */
541 WRITE_TRAN ossl_statem_server_write_transition(SSL *s)
542 {
543     OSSL_STATEM *st = &s->statem;
544 
545     /*
546      * Note that before the ClientHello we don't know what version we are going
547      * to negotiate yet, so we don't take this branch until later
548      */
549 
550     if (SSL_IS_TLS13(s))
551         return ossl_statem_server13_write_transition(s);
552 
553     switch (st->hand_state) {
554     default:
555         /* Shouldn't happen */
556         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
557                  SSL_F_OSSL_STATEM_SERVER_WRITE_TRANSITION,
558                  ERR_R_INTERNAL_ERROR);
559         return WRITE_TRAN_ERROR;
560 
561     case TLS_ST_OK:
562         if (st->request_state == TLS_ST_SW_HELLO_REQ) {
563             /* We must be trying to renegotiate */
564             st->hand_state = TLS_ST_SW_HELLO_REQ;
565             st->request_state = TLS_ST_BEFORE;
566             return WRITE_TRAN_CONTINUE;
567         }
568         /* Must be an incoming ClientHello */
569         if (!tls_setup_handshake(s)) {
570             /* SSLfatal() already called */
571             return WRITE_TRAN_ERROR;
572         }
573         /* Fall through */
574 
575     case TLS_ST_BEFORE:
576         /* Just go straight to trying to read from the client */
577         return WRITE_TRAN_FINISHED;
578 
579     case TLS_ST_SW_HELLO_REQ:
580         st->hand_state = TLS_ST_OK;
581         return WRITE_TRAN_CONTINUE;
582 
583     case TLS_ST_SR_CLNT_HELLO:
584         if (SSL_IS_DTLS(s) && !s->d1->cookie_verified
585             && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE)) {
586             st->hand_state = DTLS_ST_SW_HELLO_VERIFY_REQUEST;
587         } else if (s->renegotiate == 0 && !SSL_IS_FIRST_HANDSHAKE(s)) {
588             /* We must have rejected the renegotiation */
589             st->hand_state = TLS_ST_OK;
590             return WRITE_TRAN_CONTINUE;
591         } else {
592             st->hand_state = TLS_ST_SW_SRVR_HELLO;
593         }
594         return WRITE_TRAN_CONTINUE;
595 
596     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
597         return WRITE_TRAN_FINISHED;
598 
599     case TLS_ST_SW_SRVR_HELLO:
600         if (s->hit) {
601             if (s->ext.ticket_expected)
602                 st->hand_state = TLS_ST_SW_SESSION_TICKET;
603             else
604                 st->hand_state = TLS_ST_SW_CHANGE;
605         } else {
606             /* Check if it is anon DH or anon ECDH, */
607             /* normal PSK or SRP */
608             if (!(s->s3->tmp.new_cipher->algorithm_auth &
609                   (SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
610                 st->hand_state = TLS_ST_SW_CERT;
611             } else if (send_server_key_exchange(s)) {
612                 st->hand_state = TLS_ST_SW_KEY_EXCH;
613             } else if (send_certificate_request(s)) {
614                 st->hand_state = TLS_ST_SW_CERT_REQ;
615             } else {
616                 st->hand_state = TLS_ST_SW_SRVR_DONE;
617             }
618         }
619         return WRITE_TRAN_CONTINUE;
620 
621     case TLS_ST_SW_CERT:
622         if (s->ext.status_expected) {
623             st->hand_state = TLS_ST_SW_CERT_STATUS;
624             return WRITE_TRAN_CONTINUE;
625         }
626         /* Fall through */
627 
628     case TLS_ST_SW_CERT_STATUS:
629         if (send_server_key_exchange(s)) {
630             st->hand_state = TLS_ST_SW_KEY_EXCH;
631             return WRITE_TRAN_CONTINUE;
632         }
633         /* Fall through */
634 
635     case TLS_ST_SW_KEY_EXCH:
636         if (send_certificate_request(s)) {
637             st->hand_state = TLS_ST_SW_CERT_REQ;
638             return WRITE_TRAN_CONTINUE;
639         }
640         /* Fall through */
641 
642     case TLS_ST_SW_CERT_REQ:
643         st->hand_state = TLS_ST_SW_SRVR_DONE;
644         return WRITE_TRAN_CONTINUE;
645 
646     case TLS_ST_SW_SRVR_DONE:
647         return WRITE_TRAN_FINISHED;
648 
649     case TLS_ST_SR_FINISHED:
650         if (s->hit) {
651             st->hand_state = TLS_ST_OK;
652             return WRITE_TRAN_CONTINUE;
653         } else if (s->ext.ticket_expected) {
654             st->hand_state = TLS_ST_SW_SESSION_TICKET;
655         } else {
656             st->hand_state = TLS_ST_SW_CHANGE;
657         }
658         return WRITE_TRAN_CONTINUE;
659 
660     case TLS_ST_SW_SESSION_TICKET:
661         st->hand_state = TLS_ST_SW_CHANGE;
662         return WRITE_TRAN_CONTINUE;
663 
664     case TLS_ST_SW_CHANGE:
665         st->hand_state = TLS_ST_SW_FINISHED;
666         return WRITE_TRAN_CONTINUE;
667 
668     case TLS_ST_SW_FINISHED:
669         if (s->hit) {
670             return WRITE_TRAN_FINISHED;
671         }
672         st->hand_state = TLS_ST_OK;
673         return WRITE_TRAN_CONTINUE;
674     }
675 }
676 
677 /*
678  * Perform any pre work that needs to be done prior to sending a message from
679  * the server to the client.
680  */
681 WORK_STATE ossl_statem_server_pre_work(SSL *s, WORK_STATE wst)
682 {
683     OSSL_STATEM *st = &s->statem;
684 
685     switch (st->hand_state) {
686     default:
687         /* No pre work to be done */
688         break;
689 
690     case TLS_ST_SW_HELLO_REQ:
691         s->shutdown = 0;
692         if (SSL_IS_DTLS(s))
693             dtls1_clear_sent_buffer(s);
694         break;
695 
696     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
697         s->shutdown = 0;
698         if (SSL_IS_DTLS(s)) {
699             dtls1_clear_sent_buffer(s);
700             /* We don't buffer this message so don't use the timer */
701             st->use_timer = 0;
702         }
703         break;
704 
705     case TLS_ST_SW_SRVR_HELLO:
706         if (SSL_IS_DTLS(s)) {
707             /*
708              * Messages we write from now on should be buffered and
709              * retransmitted if necessary, so we need to use the timer now
710              */
711             st->use_timer = 1;
712         }
713         break;
714 
715     case TLS_ST_SW_SRVR_DONE:
716 #ifndef OPENSSL_NO_SCTP
717         if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
718             /* Calls SSLfatal() as required */
719             return dtls_wait_for_dry(s);
720         }
721 #endif
722         return WORK_FINISHED_CONTINUE;
723 
724     case TLS_ST_SW_SESSION_TICKET:
725         if (SSL_IS_TLS13(s) && s->sent_tickets == 0) {
726             /*
727              * Actually this is the end of the handshake, but we're going
728              * straight into writing the session ticket out. So we finish off
729              * the handshake, but keep the various buffers active.
730              *
731              * Calls SSLfatal as required.
732              */
733             return tls_finish_handshake(s, wst, 0, 0);
734         } if (SSL_IS_DTLS(s)) {
735             /*
736              * We're into the last flight. We don't retransmit the last flight
737              * unless we need to, so we don't use the timer
738              */
739             st->use_timer = 0;
740         }
741         break;
742 
743     case TLS_ST_SW_CHANGE:
744         if (SSL_IS_TLS13(s))
745             break;
746         /* Writes to s->session are only safe for initial handshakes */
747         if (s->session->cipher == NULL) {
748             s->session->cipher = s->s3->tmp.new_cipher;
749         } else if (s->session->cipher != s->s3->tmp.new_cipher) {
750             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
751                      SSL_F_OSSL_STATEM_SERVER_PRE_WORK,
752                      ERR_R_INTERNAL_ERROR);
753             return WORK_ERROR;
754         }
755         if (!s->method->ssl3_enc->setup_key_block(s)) {
756             /* SSLfatal() already called */
757             return WORK_ERROR;
758         }
759         if (SSL_IS_DTLS(s)) {
760             /*
761              * We're into the last flight. We don't retransmit the last flight
762              * unless we need to, so we don't use the timer. This might have
763              * already been set to 0 if we sent a NewSessionTicket message,
764              * but we'll set it again here in case we didn't.
765              */
766             st->use_timer = 0;
767         }
768         return WORK_FINISHED_CONTINUE;
769 
770     case TLS_ST_EARLY_DATA:
771         if (s->early_data_state != SSL_EARLY_DATA_ACCEPTING
772                 && (s->s3->flags & TLS1_FLAGS_STATELESS) == 0)
773             return WORK_FINISHED_CONTINUE;
774         /* Fall through */
775 
776     case TLS_ST_OK:
777         /* Calls SSLfatal() as required */
778         return tls_finish_handshake(s, wst, 1, 1);
779     }
780 
781     return WORK_FINISHED_CONTINUE;
782 }
783 
784 static ossl_inline int conn_is_closed(void)
785 {
786     switch (get_last_sys_error()) {
787 #if defined(EPIPE)
788     case EPIPE:
789         return 1;
790 #endif
791 #if defined(ECONNRESET)
792     case ECONNRESET:
793         return 1;
794 #endif
795 #if defined(WSAECONNRESET)
796     case WSAECONNRESET:
797         return 1;
798 #endif
799     default:
800         return 0;
801     }
802 }
803 
804 /*
805  * Perform any work that needs to be done after sending a message from the
806  * server to the client.
807  */
808 WORK_STATE ossl_statem_server_post_work(SSL *s, WORK_STATE wst)
809 {
810     OSSL_STATEM *st = &s->statem;
811 
812     s->init_num = 0;
813 
814     switch (st->hand_state) {
815     default:
816         /* No post work to be done */
817         break;
818 
819     case TLS_ST_SW_HELLO_REQ:
820         if (statem_flush(s) != 1)
821             return WORK_MORE_A;
822         if (!ssl3_init_finished_mac(s)) {
823             /* SSLfatal() already called */
824             return WORK_ERROR;
825         }
826         break;
827 
828     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
829         if (statem_flush(s) != 1)
830             return WORK_MORE_A;
831         /* HelloVerifyRequest resets Finished MAC */
832         if (s->version != DTLS1_BAD_VER && !ssl3_init_finished_mac(s)) {
833             /* SSLfatal() already called */
834             return WORK_ERROR;
835         }
836         /*
837          * The next message should be another ClientHello which we need to
838          * treat like it was the first packet
839          */
840         s->first_packet = 1;
841         break;
842 
843     case TLS_ST_SW_SRVR_HELLO:
844         if (SSL_IS_TLS13(s) && s->hello_retry_request == SSL_HRR_PENDING) {
845             if ((s->options & SSL_OP_ENABLE_MIDDLEBOX_COMPAT) == 0
846                     && statem_flush(s) != 1)
847                 return WORK_MORE_A;
848             break;
849         }
850 #ifndef OPENSSL_NO_SCTP
851         if (SSL_IS_DTLS(s) && s->hit) {
852             unsigned char sctpauthkey[64];
853             char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
854             size_t labellen;
855 
856             /*
857              * Add new shared key for SCTP-Auth, will be ignored if no
858              * SCTP used.
859              */
860             memcpy(labelbuffer, DTLS1_SCTP_AUTH_LABEL,
861                    sizeof(DTLS1_SCTP_AUTH_LABEL));
862 
863             /* Don't include the terminating zero. */
864             labellen = sizeof(labelbuffer) - 1;
865             if (s->mode & SSL_MODE_DTLS_SCTP_LABEL_LENGTH_BUG)
866                 labellen += 1;
867 
868             if (SSL_export_keying_material(s, sctpauthkey,
869                                            sizeof(sctpauthkey), labelbuffer,
870                                            labellen, NULL, 0,
871                                            0) <= 0) {
872                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
873                          SSL_F_OSSL_STATEM_SERVER_POST_WORK,
874                          ERR_R_INTERNAL_ERROR);
875                 return WORK_ERROR;
876             }
877 
878             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
879                      sizeof(sctpauthkey), sctpauthkey);
880         }
881 #endif
882         if (!SSL_IS_TLS13(s)
883                 || ((s->options & SSL_OP_ENABLE_MIDDLEBOX_COMPAT) != 0
884                     && s->hello_retry_request != SSL_HRR_COMPLETE))
885             break;
886         /* Fall through */
887 
888     case TLS_ST_SW_CHANGE:
889         if (s->hello_retry_request == SSL_HRR_PENDING) {
890             if (!statem_flush(s))
891                 return WORK_MORE_A;
892             break;
893         }
894 
895         if (SSL_IS_TLS13(s)) {
896             if (!s->method->ssl3_enc->setup_key_block(s)
897                 || !s->method->ssl3_enc->change_cipher_state(s,
898                         SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
899                 /* SSLfatal() already called */
900                 return WORK_ERROR;
901             }
902 
903             if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED
904                 && !s->method->ssl3_enc->change_cipher_state(s,
905                         SSL3_CC_HANDSHAKE |SSL3_CHANGE_CIPHER_SERVER_READ)) {
906                 /* SSLfatal() already called */
907                 return WORK_ERROR;
908             }
909             /*
910              * We don't yet know whether the next record we are going to receive
911              * is an unencrypted alert, an encrypted alert, or an encrypted
912              * handshake message. We temporarily tolerate unencrypted alerts.
913              */
914             s->statem.enc_read_state = ENC_READ_STATE_ALLOW_PLAIN_ALERTS;
915             break;
916         }
917 
918 #ifndef OPENSSL_NO_SCTP
919         if (SSL_IS_DTLS(s) && !s->hit) {
920             /*
921              * Change to new shared key of SCTP-Auth, will be ignored if
922              * no SCTP used.
923              */
924             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
925                      0, NULL);
926         }
927 #endif
928         if (!s->method->ssl3_enc->change_cipher_state(s,
929                                                       SSL3_CHANGE_CIPHER_SERVER_WRITE))
930         {
931             /* SSLfatal() already called */
932             return WORK_ERROR;
933         }
934 
935         if (SSL_IS_DTLS(s))
936             dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
937         break;
938 
939     case TLS_ST_SW_SRVR_DONE:
940         if (statem_flush(s) != 1)
941             return WORK_MORE_A;
942         break;
943 
944     case TLS_ST_SW_FINISHED:
945         if (statem_flush(s) != 1)
946             return WORK_MORE_A;
947 #ifndef OPENSSL_NO_SCTP
948         if (SSL_IS_DTLS(s) && s->hit) {
949             /*
950              * Change to new shared key of SCTP-Auth, will be ignored if
951              * no SCTP used.
952              */
953             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
954                      0, NULL);
955         }
956 #endif
957         if (SSL_IS_TLS13(s)) {
958             /* TLS 1.3 gets the secret size from the handshake md */
959             size_t dummy;
960             if (!s->method->ssl3_enc->generate_master_secret(s,
961                         s->master_secret, s->handshake_secret, 0,
962                         &dummy)
963                 || !s->method->ssl3_enc->change_cipher_state(s,
964                         SSL3_CC_APPLICATION | SSL3_CHANGE_CIPHER_SERVER_WRITE))
965             /* SSLfatal() already called */
966             return WORK_ERROR;
967         }
968         break;
969 
970     case TLS_ST_SW_CERT_REQ:
971         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
972             if (statem_flush(s) != 1)
973                 return WORK_MORE_A;
974         }
975         break;
976 
977     case TLS_ST_SW_KEY_UPDATE:
978         if (statem_flush(s) != 1)
979             return WORK_MORE_A;
980         if (!tls13_update_key(s, 1)) {
981             /* SSLfatal() already called */
982             return WORK_ERROR;
983         }
984         break;
985 
986     case TLS_ST_SW_SESSION_TICKET:
987         clear_sys_error();
988         if (SSL_IS_TLS13(s) && statem_flush(s) != 1) {
989             if (SSL_get_error(s, 0) == SSL_ERROR_SYSCALL
990                     && conn_is_closed()) {
991                 /*
992                  * We ignore connection closed errors in TLSv1.3 when sending a
993                  * NewSessionTicket and behave as if we were successful. This is
994                  * so that we are still able to read data sent to us by a client
995                  * that closes soon after the end of the handshake without
996                  * waiting to read our post-handshake NewSessionTickets.
997                  */
998                 s->rwstate = SSL_NOTHING;
999                 break;
1000             }
1001 
1002             return WORK_MORE_A;
1003         }
1004         break;
1005     }
1006 
1007     return WORK_FINISHED_CONTINUE;
1008 }
1009 
1010 /*
1011  * Get the message construction function and message type for sending from the
1012  * server
1013  *
1014  * Valid return values are:
1015  *   1: Success
1016  *   0: Error
1017  */
1018 int ossl_statem_server_construct_message(SSL *s, WPACKET *pkt,
1019                                          confunc_f *confunc, int *mt)
1020 {
1021     OSSL_STATEM *st = &s->statem;
1022 
1023     switch (st->hand_state) {
1024     default:
1025         /* Shouldn't happen */
1026         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1027                  SSL_F_OSSL_STATEM_SERVER_CONSTRUCT_MESSAGE,
1028                  SSL_R_BAD_HANDSHAKE_STATE);
1029         return 0;
1030 
1031     case TLS_ST_SW_CHANGE:
1032         if (SSL_IS_DTLS(s))
1033             *confunc = dtls_construct_change_cipher_spec;
1034         else
1035             *confunc = tls_construct_change_cipher_spec;
1036         *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
1037         break;
1038 
1039     case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
1040         *confunc = dtls_construct_hello_verify_request;
1041         *mt = DTLS1_MT_HELLO_VERIFY_REQUEST;
1042         break;
1043 
1044     case TLS_ST_SW_HELLO_REQ:
1045         /* No construction function needed */
1046         *confunc = NULL;
1047         *mt = SSL3_MT_HELLO_REQUEST;
1048         break;
1049 
1050     case TLS_ST_SW_SRVR_HELLO:
1051         *confunc = tls_construct_server_hello;
1052         *mt = SSL3_MT_SERVER_HELLO;
1053         break;
1054 
1055     case TLS_ST_SW_CERT:
1056         *confunc = tls_construct_server_certificate;
1057         *mt = SSL3_MT_CERTIFICATE;
1058         break;
1059 
1060     case TLS_ST_SW_CERT_VRFY:
1061         *confunc = tls_construct_cert_verify;
1062         *mt = SSL3_MT_CERTIFICATE_VERIFY;
1063         break;
1064 
1065 
1066     case TLS_ST_SW_KEY_EXCH:
1067         *confunc = tls_construct_server_key_exchange;
1068         *mt = SSL3_MT_SERVER_KEY_EXCHANGE;
1069         break;
1070 
1071     case TLS_ST_SW_CERT_REQ:
1072         *confunc = tls_construct_certificate_request;
1073         *mt = SSL3_MT_CERTIFICATE_REQUEST;
1074         break;
1075 
1076     case TLS_ST_SW_SRVR_DONE:
1077         *confunc = tls_construct_server_done;
1078         *mt = SSL3_MT_SERVER_DONE;
1079         break;
1080 
1081     case TLS_ST_SW_SESSION_TICKET:
1082         *confunc = tls_construct_new_session_ticket;
1083         *mt = SSL3_MT_NEWSESSION_TICKET;
1084         break;
1085 
1086     case TLS_ST_SW_CERT_STATUS:
1087         *confunc = tls_construct_cert_status;
1088         *mt = SSL3_MT_CERTIFICATE_STATUS;
1089         break;
1090 
1091     case TLS_ST_SW_FINISHED:
1092         *confunc = tls_construct_finished;
1093         *mt = SSL3_MT_FINISHED;
1094         break;
1095 
1096     case TLS_ST_EARLY_DATA:
1097         *confunc = NULL;
1098         *mt = SSL3_MT_DUMMY;
1099         break;
1100 
1101     case TLS_ST_SW_ENCRYPTED_EXTENSIONS:
1102         *confunc = tls_construct_encrypted_extensions;
1103         *mt = SSL3_MT_ENCRYPTED_EXTENSIONS;
1104         break;
1105 
1106     case TLS_ST_SW_KEY_UPDATE:
1107         *confunc = tls_construct_key_update;
1108         *mt = SSL3_MT_KEY_UPDATE;
1109         break;
1110     }
1111 
1112     return 1;
1113 }
1114 
1115 /*
1116  * Maximum size (excluding the Handshake header) of a ClientHello message,
1117  * calculated as follows:
1118  *
1119  *  2 + # client_version
1120  *  32 + # only valid length for random
1121  *  1 + # length of session_id
1122  *  32 + # maximum size for session_id
1123  *  2 + # length of cipher suites
1124  *  2^16-2 + # maximum length of cipher suites array
1125  *  1 + # length of compression_methods
1126  *  2^8-1 + # maximum length of compression methods
1127  *  2 + # length of extensions
1128  *  2^16-1 # maximum length of extensions
1129  */
1130 #define CLIENT_HELLO_MAX_LENGTH         131396
1131 
1132 #define CLIENT_KEY_EXCH_MAX_LENGTH      2048
1133 #define NEXT_PROTO_MAX_LENGTH           514
1134 
1135 /*
1136  * Returns the maximum allowed length for the current message that we are
1137  * reading. Excludes the message header.
1138  */
1139 size_t ossl_statem_server_max_message_size(SSL *s)
1140 {
1141     OSSL_STATEM *st = &s->statem;
1142 
1143     switch (st->hand_state) {
1144     default:
1145         /* Shouldn't happen */
1146         return 0;
1147 
1148     case TLS_ST_SR_CLNT_HELLO:
1149         return CLIENT_HELLO_MAX_LENGTH;
1150 
1151     case TLS_ST_SR_END_OF_EARLY_DATA:
1152         return END_OF_EARLY_DATA_MAX_LENGTH;
1153 
1154     case TLS_ST_SR_CERT:
1155         return s->max_cert_list;
1156 
1157     case TLS_ST_SR_KEY_EXCH:
1158         return CLIENT_KEY_EXCH_MAX_LENGTH;
1159 
1160     case TLS_ST_SR_CERT_VRFY:
1161         return SSL3_RT_MAX_PLAIN_LENGTH;
1162 
1163 #ifndef OPENSSL_NO_NEXTPROTONEG
1164     case TLS_ST_SR_NEXT_PROTO:
1165         return NEXT_PROTO_MAX_LENGTH;
1166 #endif
1167 
1168     case TLS_ST_SR_CHANGE:
1169         return CCS_MAX_LENGTH;
1170 
1171     case TLS_ST_SR_FINISHED:
1172         return FINISHED_MAX_LENGTH;
1173 
1174     case TLS_ST_SR_KEY_UPDATE:
1175         return KEY_UPDATE_MAX_LENGTH;
1176     }
1177 }
1178 
1179 /*
1180  * Process a message that the server has received from the client.
1181  */
1182 MSG_PROCESS_RETURN ossl_statem_server_process_message(SSL *s, PACKET *pkt)
1183 {
1184     OSSL_STATEM *st = &s->statem;
1185 
1186     switch (st->hand_state) {
1187     default:
1188         /* Shouldn't happen */
1189         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1190                  SSL_F_OSSL_STATEM_SERVER_PROCESS_MESSAGE,
1191                  ERR_R_INTERNAL_ERROR);
1192         return MSG_PROCESS_ERROR;
1193 
1194     case TLS_ST_SR_CLNT_HELLO:
1195         return tls_process_client_hello(s, pkt);
1196 
1197     case TLS_ST_SR_END_OF_EARLY_DATA:
1198         return tls_process_end_of_early_data(s, pkt);
1199 
1200     case TLS_ST_SR_CERT:
1201         return tls_process_client_certificate(s, pkt);
1202 
1203     case TLS_ST_SR_KEY_EXCH:
1204         return tls_process_client_key_exchange(s, pkt);
1205 
1206     case TLS_ST_SR_CERT_VRFY:
1207         return tls_process_cert_verify(s, pkt);
1208 
1209 #ifndef OPENSSL_NO_NEXTPROTONEG
1210     case TLS_ST_SR_NEXT_PROTO:
1211         return tls_process_next_proto(s, pkt);
1212 #endif
1213 
1214     case TLS_ST_SR_CHANGE:
1215         return tls_process_change_cipher_spec(s, pkt);
1216 
1217     case TLS_ST_SR_FINISHED:
1218         return tls_process_finished(s, pkt);
1219 
1220     case TLS_ST_SR_KEY_UPDATE:
1221         return tls_process_key_update(s, pkt);
1222 
1223     }
1224 }
1225 
1226 /*
1227  * Perform any further processing required following the receipt of a message
1228  * from the client
1229  */
1230 WORK_STATE ossl_statem_server_post_process_message(SSL *s, WORK_STATE wst)
1231 {
1232     OSSL_STATEM *st = &s->statem;
1233 
1234     switch (st->hand_state) {
1235     default:
1236         /* Shouldn't happen */
1237         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1238                  SSL_F_OSSL_STATEM_SERVER_POST_PROCESS_MESSAGE,
1239                  ERR_R_INTERNAL_ERROR);
1240         return WORK_ERROR;
1241 
1242     case TLS_ST_SR_CLNT_HELLO:
1243         return tls_post_process_client_hello(s, wst);
1244 
1245     case TLS_ST_SR_KEY_EXCH:
1246         return tls_post_process_client_key_exchange(s, wst);
1247     }
1248 }
1249 
1250 #ifndef OPENSSL_NO_SRP
1251 /* Returns 1 on success, 0 for retryable error, -1 for fatal error */
1252 static int ssl_check_srp_ext_ClientHello(SSL *s)
1253 {
1254     int ret;
1255     int al = SSL_AD_UNRECOGNIZED_NAME;
1256 
1257     if ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_kSRP) &&
1258         (s->srp_ctx.TLS_ext_srp_username_callback != NULL)) {
1259         if (s->srp_ctx.login == NULL) {
1260             /*
1261              * RFC 5054 says SHOULD reject, we do so if There is no srp
1262              * login name
1263              */
1264             SSLfatal(s, SSL_AD_UNKNOWN_PSK_IDENTITY,
1265                      SSL_F_SSL_CHECK_SRP_EXT_CLIENTHELLO,
1266                      SSL_R_PSK_IDENTITY_NOT_FOUND);
1267             return -1;
1268         } else {
1269             ret = SSL_srp_server_param_with_username(s, &al);
1270             if (ret < 0)
1271                 return 0;
1272             if (ret == SSL3_AL_FATAL) {
1273                 SSLfatal(s, al, SSL_F_SSL_CHECK_SRP_EXT_CLIENTHELLO,
1274                          al == SSL_AD_UNKNOWN_PSK_IDENTITY
1275                          ? SSL_R_PSK_IDENTITY_NOT_FOUND
1276                          : SSL_R_CLIENTHELLO_TLSEXT);
1277                 return -1;
1278             }
1279         }
1280     }
1281     return 1;
1282 }
1283 #endif
1284 
1285 int dtls_raw_hello_verify_request(WPACKET *pkt, unsigned char *cookie,
1286                                   size_t cookie_len)
1287 {
1288     /* Always use DTLS 1.0 version: see RFC 6347 */
1289     if (!WPACKET_put_bytes_u16(pkt, DTLS1_VERSION)
1290             || !WPACKET_sub_memcpy_u8(pkt, cookie, cookie_len))
1291         return 0;
1292 
1293     return 1;
1294 }
1295 
1296 int dtls_construct_hello_verify_request(SSL *s, WPACKET *pkt)
1297 {
1298     unsigned int cookie_leni;
1299     if (s->ctx->app_gen_cookie_cb == NULL ||
1300         s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
1301                                   &cookie_leni) == 0 ||
1302         cookie_leni > 255) {
1303         SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST,
1304                  SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
1305         return 0;
1306     }
1307     s->d1->cookie_len = cookie_leni;
1308 
1309     if (!dtls_raw_hello_verify_request(pkt, s->d1->cookie,
1310                                               s->d1->cookie_len)) {
1311         SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST,
1312                  ERR_R_INTERNAL_ERROR);
1313         return 0;
1314     }
1315 
1316     return 1;
1317 }
1318 
1319 #ifndef OPENSSL_NO_EC
1320 /*-
1321  * ssl_check_for_safari attempts to fingerprint Safari using OS X
1322  * SecureTransport using the TLS extension block in |hello|.
1323  * Safari, since 10.6, sends exactly these extensions, in this order:
1324  *   SNI,
1325  *   elliptic_curves
1326  *   ec_point_formats
1327  *   signature_algorithms (for TLSv1.2 only)
1328  *
1329  * We wish to fingerprint Safari because they broke ECDHE-ECDSA support in 10.8,
1330  * but they advertise support. So enabling ECDHE-ECDSA ciphers breaks them.
1331  * Sadly we cannot differentiate 10.6, 10.7 and 10.8.4 (which work), from
1332  * 10.8..10.8.3 (which don't work).
1333  */
1334 static void ssl_check_for_safari(SSL *s, const CLIENTHELLO_MSG *hello)
1335 {
1336     static const unsigned char kSafariExtensionsBlock[] = {
1337         0x00, 0x0a,             /* elliptic_curves extension */
1338         0x00, 0x08,             /* 8 bytes */
1339         0x00, 0x06,             /* 6 bytes of curve ids */
1340         0x00, 0x17,             /* P-256 */
1341         0x00, 0x18,             /* P-384 */
1342         0x00, 0x19,             /* P-521 */
1343 
1344         0x00, 0x0b,             /* ec_point_formats */
1345         0x00, 0x02,             /* 2 bytes */
1346         0x01,                   /* 1 point format */
1347         0x00,                   /* uncompressed */
1348         /* The following is only present in TLS 1.2 */
1349         0x00, 0x0d,             /* signature_algorithms */
1350         0x00, 0x0c,             /* 12 bytes */
1351         0x00, 0x0a,             /* 10 bytes */
1352         0x05, 0x01,             /* SHA-384/RSA */
1353         0x04, 0x01,             /* SHA-256/RSA */
1354         0x02, 0x01,             /* SHA-1/RSA */
1355         0x04, 0x03,             /* SHA-256/ECDSA */
1356         0x02, 0x03,             /* SHA-1/ECDSA */
1357     };
1358     /* Length of the common prefix (first two extensions). */
1359     static const size_t kSafariCommonExtensionsLength = 18;
1360     unsigned int type;
1361     PACKET sni, tmppkt;
1362     size_t ext_len;
1363 
1364     tmppkt = hello->extensions;
1365 
1366     if (!PACKET_forward(&tmppkt, 2)
1367         || !PACKET_get_net_2(&tmppkt, &type)
1368         || !PACKET_get_length_prefixed_2(&tmppkt, &sni)) {
1369         return;
1370     }
1371 
1372     if (type != TLSEXT_TYPE_server_name)
1373         return;
1374 
1375     ext_len = TLS1_get_client_version(s) >= TLS1_2_VERSION ?
1376         sizeof(kSafariExtensionsBlock) : kSafariCommonExtensionsLength;
1377 
1378     s->s3->is_probably_safari = PACKET_equal(&tmppkt, kSafariExtensionsBlock,
1379                                              ext_len);
1380 }
1381 #endif                          /* !OPENSSL_NO_EC */
1382 
1383 MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
1384 {
1385     /* |cookie| will only be initialized for DTLS. */
1386     PACKET session_id, compression, extensions, cookie;
1387     static const unsigned char null_compression = 0;
1388     CLIENTHELLO_MSG *clienthello = NULL;
1389 
1390     /* Check if this is actually an unexpected renegotiation ClientHello */
1391     if (s->renegotiate == 0 && !SSL_IS_FIRST_HANDSHAKE(s)) {
1392         if (!ossl_assert(!SSL_IS_TLS13(s))) {
1393             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1394                      ERR_R_INTERNAL_ERROR);
1395             goto err;
1396         }
1397         if ((s->options & SSL_OP_NO_RENEGOTIATION) != 0
1398                 || (!s->s3->send_connection_binding
1399                     && (s->options
1400                         & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) == 0)) {
1401             ssl3_send_alert(s, SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
1402             return MSG_PROCESS_FINISHED_READING;
1403         }
1404         s->renegotiate = 1;
1405         s->new_session = 1;
1406     }
1407 
1408     clienthello = OPENSSL_zalloc(sizeof(*clienthello));
1409     if (clienthello == NULL) {
1410         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1411                  ERR_R_INTERNAL_ERROR);
1412         goto err;
1413     }
1414 
1415     /*
1416      * First, parse the raw ClientHello data into the CLIENTHELLO_MSG structure.
1417      */
1418     clienthello->isv2 = RECORD_LAYER_is_sslv2_record(&s->rlayer);
1419     PACKET_null_init(&cookie);
1420 
1421     if (clienthello->isv2) {
1422         unsigned int mt;
1423 
1424         if (!SSL_IS_FIRST_HANDSHAKE(s)
1425                 || s->hello_retry_request != SSL_HRR_NONE) {
1426             SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
1427                      SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_UNEXPECTED_MESSAGE);
1428             goto err;
1429         }
1430 
1431         /*-
1432          * An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2
1433          * header is sent directly on the wire, not wrapped as a TLS
1434          * record. Our record layer just processes the message length and passes
1435          * the rest right through. Its format is:
1436          * Byte  Content
1437          * 0-1   msg_length - decoded by the record layer
1438          * 2     msg_type - s->init_msg points here
1439          * 3-4   version
1440          * 5-6   cipher_spec_length
1441          * 7-8   session_id_length
1442          * 9-10  challenge_length
1443          * ...   ...
1444          */
1445 
1446         if (!PACKET_get_1(pkt, &mt)
1447             || mt != SSL2_MT_CLIENT_HELLO) {
1448             /*
1449              * Should never happen. We should have tested this in the record
1450              * layer in order to have determined that this is a SSLv2 record
1451              * in the first place
1452              */
1453             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1454                      ERR_R_INTERNAL_ERROR);
1455             goto err;
1456         }
1457     }
1458 
1459     if (!PACKET_get_net_2(pkt, &clienthello->legacy_version)) {
1460         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1461                  SSL_R_LENGTH_TOO_SHORT);
1462         goto err;
1463     }
1464 
1465     /* Parse the message and load client random. */
1466     if (clienthello->isv2) {
1467         /*
1468          * Handle an SSLv2 backwards compatible ClientHello
1469          * Note, this is only for SSLv3+ using the backward compatible format.
1470          * Real SSLv2 is not supported, and is rejected below.
1471          */
1472         unsigned int ciphersuite_len, session_id_len, challenge_len;
1473         PACKET challenge;
1474 
1475         if (!PACKET_get_net_2(pkt, &ciphersuite_len)
1476             || !PACKET_get_net_2(pkt, &session_id_len)
1477             || !PACKET_get_net_2(pkt, &challenge_len)) {
1478             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1479                      SSL_R_RECORD_LENGTH_MISMATCH);
1480             goto err;
1481         }
1482 
1483         if (session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
1484             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1485                      SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
1486             goto err;
1487         }
1488 
1489         if (!PACKET_get_sub_packet(pkt, &clienthello->ciphersuites,
1490                                    ciphersuite_len)
1491             || !PACKET_copy_bytes(pkt, clienthello->session_id, session_id_len)
1492             || !PACKET_get_sub_packet(pkt, &challenge, challenge_len)
1493             /* No extensions. */
1494             || PACKET_remaining(pkt) != 0) {
1495             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1496                      SSL_R_RECORD_LENGTH_MISMATCH);
1497             goto err;
1498         }
1499         clienthello->session_id_len = session_id_len;
1500 
1501         /* Load the client random and compression list. We use SSL3_RANDOM_SIZE
1502          * here rather than sizeof(clienthello->random) because that is the limit
1503          * for SSLv3 and it is fixed. It won't change even if
1504          * sizeof(clienthello->random) does.
1505          */
1506         challenge_len = challenge_len > SSL3_RANDOM_SIZE
1507                         ? SSL3_RANDOM_SIZE : challenge_len;
1508         memset(clienthello->random, 0, SSL3_RANDOM_SIZE);
1509         if (!PACKET_copy_bytes(&challenge,
1510                                clienthello->random + SSL3_RANDOM_SIZE -
1511                                challenge_len, challenge_len)
1512             /* Advertise only null compression. */
1513             || !PACKET_buf_init(&compression, &null_compression, 1)) {
1514             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1515                      ERR_R_INTERNAL_ERROR);
1516             goto err;
1517         }
1518 
1519         PACKET_null_init(&clienthello->extensions);
1520     } else {
1521         /* Regular ClientHello. */
1522         if (!PACKET_copy_bytes(pkt, clienthello->random, SSL3_RANDOM_SIZE)
1523             || !PACKET_get_length_prefixed_1(pkt, &session_id)
1524             || !PACKET_copy_all(&session_id, clienthello->session_id,
1525                     SSL_MAX_SSL_SESSION_ID_LENGTH,
1526                     &clienthello->session_id_len)) {
1527             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1528                      SSL_R_LENGTH_MISMATCH);
1529             goto err;
1530         }
1531 
1532         if (SSL_IS_DTLS(s)) {
1533             if (!PACKET_get_length_prefixed_1(pkt, &cookie)) {
1534                 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1535                          SSL_R_LENGTH_MISMATCH);
1536                 goto err;
1537             }
1538             if (!PACKET_copy_all(&cookie, clienthello->dtls_cookie,
1539                                  DTLS1_COOKIE_LENGTH,
1540                                  &clienthello->dtls_cookie_len)) {
1541                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1542                          SSL_F_TLS_PROCESS_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
1543                 goto err;
1544             }
1545             /*
1546              * If we require cookies and this ClientHello doesn't contain one,
1547              * just return since we do not want to allocate any memory yet.
1548              * So check cookie length...
1549              */
1550             if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
1551                 if (clienthello->dtls_cookie_len == 0) {
1552                     OPENSSL_free(clienthello);
1553                     return MSG_PROCESS_FINISHED_READING;
1554                 }
1555             }
1556         }
1557 
1558         if (!PACKET_get_length_prefixed_2(pkt, &clienthello->ciphersuites)) {
1559             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1560                      SSL_R_LENGTH_MISMATCH);
1561             goto err;
1562         }
1563 
1564         if (!PACKET_get_length_prefixed_1(pkt, &compression)) {
1565             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1566                      SSL_R_LENGTH_MISMATCH);
1567             goto err;
1568         }
1569 
1570         /* Could be empty. */
1571         if (PACKET_remaining(pkt) == 0) {
1572             PACKET_null_init(&clienthello->extensions);
1573         } else {
1574             if (!PACKET_get_length_prefixed_2(pkt, &clienthello->extensions)
1575                     || PACKET_remaining(pkt) != 0) {
1576                 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1577                          SSL_R_LENGTH_MISMATCH);
1578                 goto err;
1579             }
1580         }
1581     }
1582 
1583     if (!PACKET_copy_all(&compression, clienthello->compressions,
1584                          MAX_COMPRESSIONS_SIZE,
1585                          &clienthello->compressions_len)) {
1586         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_HELLO,
1587                  ERR_R_INTERNAL_ERROR);
1588         goto err;
1589     }
1590 
1591     /* Preserve the raw extensions PACKET for later use */
1592     extensions = clienthello->extensions;
1593     if (!tls_collect_extensions(s, &extensions, SSL_EXT_CLIENT_HELLO,
1594                                 &clienthello->pre_proc_exts,
1595                                 &clienthello->pre_proc_exts_len, 1)) {
1596         /* SSLfatal already been called */
1597         goto err;
1598     }
1599     s->clienthello = clienthello;
1600 
1601     return MSG_PROCESS_CONTINUE_PROCESSING;
1602 
1603  err:
1604     if (clienthello != NULL)
1605         OPENSSL_free(clienthello->pre_proc_exts);
1606     OPENSSL_free(clienthello);
1607 
1608     return MSG_PROCESS_ERROR;
1609 }
1610 
1611 static int tls_early_post_process_client_hello(SSL *s)
1612 {
1613     unsigned int j;
1614     int i, al = SSL_AD_INTERNAL_ERROR;
1615     int protverr;
1616     size_t loop;
1617     unsigned long id;
1618 #ifndef OPENSSL_NO_COMP
1619     SSL_COMP *comp = NULL;
1620 #endif
1621     const SSL_CIPHER *c;
1622     STACK_OF(SSL_CIPHER) *ciphers = NULL;
1623     STACK_OF(SSL_CIPHER) *scsvs = NULL;
1624     CLIENTHELLO_MSG *clienthello = s->clienthello;
1625     DOWNGRADE dgrd = DOWNGRADE_NONE;
1626 
1627     /* Finished parsing the ClientHello, now we can start processing it */
1628     /* Give the ClientHello callback a crack at things */
1629     if (s->ctx->client_hello_cb != NULL) {
1630         /* A failure in the ClientHello callback terminates the connection. */
1631         switch (s->ctx->client_hello_cb(s, &al, s->ctx->client_hello_cb_arg)) {
1632         case SSL_CLIENT_HELLO_SUCCESS:
1633             break;
1634         case SSL_CLIENT_HELLO_RETRY:
1635             s->rwstate = SSL_CLIENT_HELLO_CB;
1636             return -1;
1637         case SSL_CLIENT_HELLO_ERROR:
1638         default:
1639             SSLfatal(s, al,
1640                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1641                      SSL_R_CALLBACK_FAILED);
1642             goto err;
1643         }
1644     }
1645 
1646     /* Set up the client_random */
1647     memcpy(s->s3->client_random, clienthello->random, SSL3_RANDOM_SIZE);
1648 
1649     /* Choose the version */
1650 
1651     if (clienthello->isv2) {
1652         if (clienthello->legacy_version == SSL2_VERSION
1653                 || (clienthello->legacy_version & 0xff00)
1654                    != (SSL3_VERSION_MAJOR << 8)) {
1655             /*
1656              * This is real SSLv2 or something completely unknown. We don't
1657              * support it.
1658              */
1659             SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
1660                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1661                      SSL_R_UNKNOWN_PROTOCOL);
1662             goto err;
1663         }
1664         /* SSLv3/TLS */
1665         s->client_version = clienthello->legacy_version;
1666     }
1667     /*
1668      * Do SSL/TLS version negotiation if applicable. For DTLS we just check
1669      * versions are potentially compatible. Version negotiation comes later.
1670      */
1671     if (!SSL_IS_DTLS(s)) {
1672         protverr = ssl_choose_server_version(s, clienthello, &dgrd);
1673     } else if (s->method->version != DTLS_ANY_VERSION &&
1674                DTLS_VERSION_LT((int)clienthello->legacy_version, s->version)) {
1675         protverr = SSL_R_VERSION_TOO_LOW;
1676     } else {
1677         protverr = 0;
1678     }
1679 
1680     if (protverr) {
1681         if (SSL_IS_FIRST_HANDSHAKE(s)) {
1682             /* like ssl3_get_record, send alert using remote version number */
1683             s->version = s->client_version = clienthello->legacy_version;
1684         }
1685         SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
1686                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO, protverr);
1687         goto err;
1688     }
1689 
1690     /* TLSv1.3 specifies that a ClientHello must end on a record boundary */
1691     if (SSL_IS_TLS13(s) && RECORD_LAYER_processed_read_pending(&s->rlayer)) {
1692         SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
1693                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1694                  SSL_R_NOT_ON_RECORD_BOUNDARY);
1695         goto err;
1696     }
1697 
1698     if (SSL_IS_DTLS(s)) {
1699         /* Empty cookie was already handled above by returning early. */
1700         if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
1701             if (s->ctx->app_verify_cookie_cb != NULL) {
1702                 if (s->ctx->app_verify_cookie_cb(s, clienthello->dtls_cookie,
1703                         clienthello->dtls_cookie_len) == 0) {
1704                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1705                              SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1706                              SSL_R_COOKIE_MISMATCH);
1707                     goto err;
1708                     /* else cookie verification succeeded */
1709                 }
1710                 /* default verification */
1711             } else if (s->d1->cookie_len != clienthello->dtls_cookie_len
1712                     || memcmp(clienthello->dtls_cookie, s->d1->cookie,
1713                               s->d1->cookie_len) != 0) {
1714                 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1715                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1716                          SSL_R_COOKIE_MISMATCH);
1717                 goto err;
1718             }
1719             s->d1->cookie_verified = 1;
1720         }
1721         if (s->method->version == DTLS_ANY_VERSION) {
1722             protverr = ssl_choose_server_version(s, clienthello, &dgrd);
1723             if (protverr != 0) {
1724                 s->version = s->client_version;
1725                 SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
1726                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO, protverr);
1727                 goto err;
1728             }
1729         }
1730     }
1731 
1732     s->hit = 0;
1733 
1734     if (!ssl_cache_cipherlist(s, &clienthello->ciphersuites,
1735                               clienthello->isv2) ||
1736         !bytes_to_cipher_list(s, &clienthello->ciphersuites, &ciphers, &scsvs,
1737                               clienthello->isv2, 1)) {
1738         /* SSLfatal() already called */
1739         goto err;
1740     }
1741 
1742     s->s3->send_connection_binding = 0;
1743     /* Check what signalling cipher-suite values were received. */
1744     if (scsvs != NULL) {
1745         for(i = 0; i < sk_SSL_CIPHER_num(scsvs); i++) {
1746             c = sk_SSL_CIPHER_value(scsvs, i);
1747             if (SSL_CIPHER_get_id(c) == SSL3_CK_SCSV) {
1748                 if (s->renegotiate) {
1749                     /* SCSV is fatal if renegotiating */
1750                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1751                              SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1752                              SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING);
1753                     goto err;
1754                 }
1755                 s->s3->send_connection_binding = 1;
1756             } else if (SSL_CIPHER_get_id(c) == SSL3_CK_FALLBACK_SCSV &&
1757                        !ssl_check_version_downgrade(s)) {
1758                 /*
1759                  * This SCSV indicates that the client previously tried
1760                  * a higher version.  We should fail if the current version
1761                  * is an unexpected downgrade, as that indicates that the first
1762                  * connection may have been tampered with in order to trigger
1763                  * an insecure downgrade.
1764                  */
1765                 SSLfatal(s, SSL_AD_INAPPROPRIATE_FALLBACK,
1766                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1767                          SSL_R_INAPPROPRIATE_FALLBACK);
1768                 goto err;
1769             }
1770         }
1771     }
1772 
1773     /* For TLSv1.3 we must select the ciphersuite *before* session resumption */
1774     if (SSL_IS_TLS13(s)) {
1775         const SSL_CIPHER *cipher =
1776             ssl3_choose_cipher(s, ciphers, SSL_get_ciphers(s));
1777 
1778         if (cipher == NULL) {
1779             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1780                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1781                      SSL_R_NO_SHARED_CIPHER);
1782             goto err;
1783         }
1784         if (s->hello_retry_request == SSL_HRR_PENDING
1785                 && (s->s3->tmp.new_cipher == NULL
1786                     || s->s3->tmp.new_cipher->id != cipher->id)) {
1787             /*
1788              * A previous HRR picked a different ciphersuite to the one we
1789              * just selected. Something must have changed.
1790              */
1791             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1792                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1793                      SSL_R_BAD_CIPHER);
1794             goto err;
1795         }
1796         s->s3->tmp.new_cipher = cipher;
1797     }
1798 
1799     /* We need to do this before getting the session */
1800     if (!tls_parse_extension(s, TLSEXT_IDX_extended_master_secret,
1801                              SSL_EXT_CLIENT_HELLO,
1802                              clienthello->pre_proc_exts, NULL, 0)) {
1803         /* SSLfatal() already called */
1804         goto err;
1805     }
1806 
1807     /*
1808      * We don't allow resumption in a backwards compatible ClientHello.
1809      * TODO(openssl-team): in TLS1.1+, session_id MUST be empty.
1810      *
1811      * Versions before 0.9.7 always allow clients to resume sessions in
1812      * renegotiation. 0.9.7 and later allow this by default, but optionally
1813      * ignore resumption requests with flag
1814      * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag rather
1815      * than a change to default behavior so that applications relying on
1816      * this for security won't even compile against older library versions).
1817      * 1.0.1 and later also have a function SSL_renegotiate_abbreviated() to
1818      * request renegotiation but not a new session (s->new_session remains
1819      * unset): for servers, this essentially just means that the
1820      * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
1821      * ignored.
1822      */
1823     if (clienthello->isv2 ||
1824         (s->new_session &&
1825          (s->options & SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
1826         if (!ssl_get_new_session(s, 1)) {
1827             /* SSLfatal() already called */
1828             goto err;
1829         }
1830     } else {
1831         i = ssl_get_prev_session(s, clienthello);
1832         if (i == 1) {
1833             /* previous session */
1834             s->hit = 1;
1835         } else if (i == -1) {
1836             /* SSLfatal() already called */
1837             goto err;
1838         } else {
1839             /* i == 0 */
1840             if (!ssl_get_new_session(s, 1)) {
1841                 /* SSLfatal() already called */
1842                 goto err;
1843             }
1844         }
1845     }
1846 
1847     if (SSL_IS_TLS13(s)) {
1848         memcpy(s->tmp_session_id, s->clienthello->session_id,
1849                s->clienthello->session_id_len);
1850         s->tmp_session_id_len = s->clienthello->session_id_len;
1851     }
1852 
1853     /*
1854      * If it is a hit, check that the cipher is in the list. In TLSv1.3 we check
1855      * ciphersuite compatibility with the session as part of resumption.
1856      */
1857     if (!SSL_IS_TLS13(s) && s->hit) {
1858         j = 0;
1859         id = s->session->cipher->id;
1860 
1861 #ifdef CIPHER_DEBUG
1862         fprintf(stderr, "client sent %d ciphers\n", sk_SSL_CIPHER_num(ciphers));
1863 #endif
1864         for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
1865             c = sk_SSL_CIPHER_value(ciphers, i);
1866 #ifdef CIPHER_DEBUG
1867             fprintf(stderr, "client [%2d of %2d]:%s\n",
1868                     i, sk_SSL_CIPHER_num(ciphers), SSL_CIPHER_get_name(c));
1869 #endif
1870             if (c->id == id) {
1871                 j = 1;
1872                 break;
1873             }
1874         }
1875         if (j == 0) {
1876             /*
1877              * we need to have the cipher in the cipher list if we are asked
1878              * to reuse it
1879              */
1880             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1881                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1882                      SSL_R_REQUIRED_CIPHER_MISSING);
1883             goto err;
1884         }
1885     }
1886 
1887     for (loop = 0; loop < clienthello->compressions_len; loop++) {
1888         if (clienthello->compressions[loop] == 0)
1889             break;
1890     }
1891 
1892     if (loop >= clienthello->compressions_len) {
1893         /* no compress */
1894         SSLfatal(s, SSL_AD_DECODE_ERROR,
1895                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1896                  SSL_R_NO_COMPRESSION_SPECIFIED);
1897         goto err;
1898     }
1899 
1900 #ifndef OPENSSL_NO_EC
1901     if (s->options & SSL_OP_SAFARI_ECDHE_ECDSA_BUG)
1902         ssl_check_for_safari(s, clienthello);
1903 #endif                          /* !OPENSSL_NO_EC */
1904 
1905     /* TLS extensions */
1906     if (!tls_parse_all_extensions(s, SSL_EXT_CLIENT_HELLO,
1907                                   clienthello->pre_proc_exts, NULL, 0, 1)) {
1908         /* SSLfatal() already called */
1909         goto err;
1910     }
1911 
1912     /*
1913      * Check if we want to use external pre-shared secret for this handshake
1914      * for not reused session only. We need to generate server_random before
1915      * calling tls_session_secret_cb in order to allow SessionTicket
1916      * processing to use it in key derivation.
1917      */
1918     {
1919         unsigned char *pos;
1920         pos = s->s3->server_random;
1921         if (ssl_fill_hello_random(s, 1, pos, SSL3_RANDOM_SIZE, dgrd) <= 0) {
1922             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1923                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1924                      ERR_R_INTERNAL_ERROR);
1925             goto err;
1926         }
1927     }
1928 
1929     if (!s->hit
1930             && s->version >= TLS1_VERSION
1931             && !SSL_IS_TLS13(s)
1932             && !SSL_IS_DTLS(s)
1933             && s->ext.session_secret_cb) {
1934         const SSL_CIPHER *pref_cipher = NULL;
1935         /*
1936          * s->session->master_key_length is a size_t, but this is an int for
1937          * backwards compat reasons
1938          */
1939         int master_key_length;
1940 
1941         master_key_length = sizeof(s->session->master_key);
1942         if (s->ext.session_secret_cb(s, s->session->master_key,
1943                                      &master_key_length, ciphers,
1944                                      &pref_cipher,
1945                                      s->ext.session_secret_cb_arg)
1946                 && master_key_length > 0) {
1947             s->session->master_key_length = master_key_length;
1948             s->hit = 1;
1949             s->peer_ciphers = ciphers;
1950             s->session->verify_result = X509_V_OK;
1951 
1952             ciphers = NULL;
1953 
1954             /* check if some cipher was preferred by call back */
1955             if (pref_cipher == NULL)
1956                 pref_cipher = ssl3_choose_cipher(s, s->peer_ciphers,
1957                                                  SSL_get_ciphers(s));
1958             if (pref_cipher == NULL) {
1959                 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1960                          SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1961                          SSL_R_NO_SHARED_CIPHER);
1962                 goto err;
1963             }
1964 
1965             s->session->cipher = pref_cipher;
1966             sk_SSL_CIPHER_free(s->cipher_list);
1967             s->cipher_list = sk_SSL_CIPHER_dup(s->peer_ciphers);
1968             sk_SSL_CIPHER_free(s->cipher_list_by_id);
1969             s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->peer_ciphers);
1970         }
1971     }
1972 
1973     /*
1974      * Worst case, we will use the NULL compression, but if we have other
1975      * options, we will now look for them.  We have complen-1 compression
1976      * algorithms from the client, starting at q.
1977      */
1978     s->s3->tmp.new_compression = NULL;
1979     if (SSL_IS_TLS13(s)) {
1980         /*
1981          * We already checked above that the NULL compression method appears in
1982          * the list. Now we check there aren't any others (which is illegal in
1983          * a TLSv1.3 ClientHello.
1984          */
1985         if (clienthello->compressions_len != 1) {
1986             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1987                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
1988                      SSL_R_INVALID_COMPRESSION_ALGORITHM);
1989             goto err;
1990         }
1991     }
1992 #ifndef OPENSSL_NO_COMP
1993     /* This only happens if we have a cache hit */
1994     else if (s->session->compress_meth != 0) {
1995         int m, comp_id = s->session->compress_meth;
1996         unsigned int k;
1997         /* Perform sanity checks on resumed compression algorithm */
1998         /* Can't disable compression */
1999         if (!ssl_allow_compression(s)) {
2000             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2001                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2002                      SSL_R_INCONSISTENT_COMPRESSION);
2003             goto err;
2004         }
2005         /* Look for resumed compression method */
2006         for (m = 0; m < sk_SSL_COMP_num(s->ctx->comp_methods); m++) {
2007             comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
2008             if (comp_id == comp->id) {
2009                 s->s3->tmp.new_compression = comp;
2010                 break;
2011             }
2012         }
2013         if (s->s3->tmp.new_compression == NULL) {
2014             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2015                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2016                      SSL_R_INVALID_COMPRESSION_ALGORITHM);
2017             goto err;
2018         }
2019         /* Look for resumed method in compression list */
2020         for (k = 0; k < clienthello->compressions_len; k++) {
2021             if (clienthello->compressions[k] == comp_id)
2022                 break;
2023         }
2024         if (k >= clienthello->compressions_len) {
2025             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
2026                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2027                      SSL_R_REQUIRED_COMPRESSION_ALGORITHM_MISSING);
2028             goto err;
2029         }
2030     } else if (s->hit) {
2031         comp = NULL;
2032     } else if (ssl_allow_compression(s) && s->ctx->comp_methods) {
2033         /* See if we have a match */
2034         int m, nn, v, done = 0;
2035         unsigned int o;
2036 
2037         nn = sk_SSL_COMP_num(s->ctx->comp_methods);
2038         for (m = 0; m < nn; m++) {
2039             comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
2040             v = comp->id;
2041             for (o = 0; o < clienthello->compressions_len; o++) {
2042                 if (v == clienthello->compressions[o]) {
2043                     done = 1;
2044                     break;
2045                 }
2046             }
2047             if (done)
2048                 break;
2049         }
2050         if (done)
2051             s->s3->tmp.new_compression = comp;
2052         else
2053             comp = NULL;
2054     }
2055 #else
2056     /*
2057      * If compression is disabled we'd better not try to resume a session
2058      * using compression.
2059      */
2060     if (s->session->compress_meth != 0) {
2061         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2062                  SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2063                  SSL_R_INCONSISTENT_COMPRESSION);
2064         goto err;
2065     }
2066 #endif
2067 
2068     /*
2069      * Given s->peer_ciphers and SSL_get_ciphers, we must pick a cipher
2070      */
2071 
2072     if (!s->hit || SSL_IS_TLS13(s)) {
2073         sk_SSL_CIPHER_free(s->peer_ciphers);
2074         s->peer_ciphers = ciphers;
2075         if (ciphers == NULL) {
2076             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2077                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
2078                      ERR_R_INTERNAL_ERROR);
2079             goto err;
2080         }
2081         ciphers = NULL;
2082     }
2083 
2084     if (!s->hit) {
2085 #ifdef OPENSSL_NO_COMP
2086         s->session->compress_meth = 0;
2087 #else
2088         s->session->compress_meth = (comp == NULL) ? 0 : comp->id;
2089 #endif
2090         if (!tls1_set_server_sigalgs(s)) {
2091             /* SSLfatal() already called */
2092             goto err;
2093         }
2094     }
2095 
2096     sk_SSL_CIPHER_free(ciphers);
2097     sk_SSL_CIPHER_free(scsvs);
2098     OPENSSL_free(clienthello->pre_proc_exts);
2099     OPENSSL_free(s->clienthello);
2100     s->clienthello = NULL;
2101     return 1;
2102  err:
2103     sk_SSL_CIPHER_free(ciphers);
2104     sk_SSL_CIPHER_free(scsvs);
2105     OPENSSL_free(clienthello->pre_proc_exts);
2106     OPENSSL_free(s->clienthello);
2107     s->clienthello = NULL;
2108 
2109     return 0;
2110 }
2111 
2112 /*
2113  * Call the status request callback if needed. Upon success, returns 1.
2114  * Upon failure, returns 0.
2115  */
2116 static int tls_handle_status_request(SSL *s)
2117 {
2118     s->ext.status_expected = 0;
2119 
2120     /*
2121      * If status request then ask callback what to do. Note: this must be
2122      * called after servername callbacks in case the certificate has changed,
2123      * and must be called after the cipher has been chosen because this may
2124      * influence which certificate is sent
2125      */
2126     if (s->ext.status_type != TLSEXT_STATUSTYPE_nothing && s->ctx != NULL
2127             && s->ctx->ext.status_cb != NULL) {
2128         int ret;
2129 
2130         /* If no certificate can't return certificate status */
2131         if (s->s3->tmp.cert != NULL) {
2132             /*
2133              * Set current certificate to one we will use so SSL_get_certificate
2134              * et al can pick it up.
2135              */
2136             s->cert->key = s->s3->tmp.cert;
2137             ret = s->ctx->ext.status_cb(s, s->ctx->ext.status_arg);
2138             switch (ret) {
2139                 /* We don't want to send a status request response */
2140             case SSL_TLSEXT_ERR_NOACK:
2141                 s->ext.status_expected = 0;
2142                 break;
2143                 /* status request response should be sent */
2144             case SSL_TLSEXT_ERR_OK:
2145                 if (s->ext.ocsp.resp)
2146                     s->ext.status_expected = 1;
2147                 break;
2148                 /* something bad happened */
2149             case SSL_TLSEXT_ERR_ALERT_FATAL:
2150             default:
2151                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2152                          SSL_F_TLS_HANDLE_STATUS_REQUEST,
2153                          SSL_R_CLIENTHELLO_TLSEXT);
2154                 return 0;
2155             }
2156         }
2157     }
2158 
2159     return 1;
2160 }
2161 
2162 /*
2163  * Call the alpn_select callback if needed. Upon success, returns 1.
2164  * Upon failure, returns 0.
2165  */
2166 int tls_handle_alpn(SSL *s)
2167 {
2168     const unsigned char *selected = NULL;
2169     unsigned char selected_len = 0;
2170 
2171     if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
2172         int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
2173                                            s->s3->alpn_proposed,
2174                                            (unsigned int)s->s3->alpn_proposed_len,
2175                                            s->ctx->ext.alpn_select_cb_arg);
2176 
2177         if (r == SSL_TLSEXT_ERR_OK) {
2178             OPENSSL_free(s->s3->alpn_selected);
2179             s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
2180             if (s->s3->alpn_selected == NULL) {
2181                 s->s3->alpn_selected_len = 0;
2182                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_HANDLE_ALPN,
2183                          ERR_R_INTERNAL_ERROR);
2184                 return 0;
2185             }
2186             s->s3->alpn_selected_len = selected_len;
2187 #ifndef OPENSSL_NO_NEXTPROTONEG
2188             /* ALPN takes precedence over NPN. */
2189             s->s3->npn_seen = 0;
2190 #endif
2191 
2192             /* Check ALPN is consistent with session */
2193             if (s->session->ext.alpn_selected == NULL
2194                         || selected_len != s->session->ext.alpn_selected_len
2195                         || memcmp(selected, s->session->ext.alpn_selected,
2196                                   selected_len) != 0) {
2197                 /* Not consistent so can't be used for early_data */
2198                 s->ext.early_data_ok = 0;
2199 
2200                 if (!s->hit) {
2201                     /*
2202                      * This is a new session and so alpn_selected should have
2203                      * been initialised to NULL. We should update it with the
2204                      * selected ALPN.
2205                      */
2206                     if (!ossl_assert(s->session->ext.alpn_selected == NULL)) {
2207                         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2208                                  SSL_F_TLS_HANDLE_ALPN,
2209                                  ERR_R_INTERNAL_ERROR);
2210                         return 0;
2211                     }
2212                     s->session->ext.alpn_selected = OPENSSL_memdup(selected,
2213                                                                    selected_len);
2214                     if (s->session->ext.alpn_selected == NULL) {
2215                         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2216                                  SSL_F_TLS_HANDLE_ALPN,
2217                                  ERR_R_INTERNAL_ERROR);
2218                         return 0;
2219                     }
2220                     s->session->ext.alpn_selected_len = selected_len;
2221                 }
2222             }
2223 
2224             return 1;
2225         } else if (r != SSL_TLSEXT_ERR_NOACK) {
2226             SSLfatal(s, SSL_AD_NO_APPLICATION_PROTOCOL, SSL_F_TLS_HANDLE_ALPN,
2227                      SSL_R_NO_APPLICATION_PROTOCOL);
2228             return 0;
2229         }
2230         /*
2231          * If r == SSL_TLSEXT_ERR_NOACK then behave as if no callback was
2232          * present.
2233          */
2234     }
2235 
2236     /* Check ALPN is consistent with session */
2237     if (s->session->ext.alpn_selected != NULL) {
2238         /* Not consistent so can't be used for early_data */
2239         s->ext.early_data_ok = 0;
2240     }
2241 
2242     return 1;
2243 }
2244 
2245 WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
2246 {
2247     const SSL_CIPHER *cipher;
2248 
2249     if (wst == WORK_MORE_A) {
2250         int rv = tls_early_post_process_client_hello(s);
2251         if (rv == 0) {
2252             /* SSLfatal() was already called */
2253             goto err;
2254         }
2255         if (rv < 0)
2256             return WORK_MORE_A;
2257         wst = WORK_MORE_B;
2258     }
2259     if (wst == WORK_MORE_B) {
2260         if (!s->hit || SSL_IS_TLS13(s)) {
2261             /* Let cert callback update server certificates if required */
2262             if (!s->hit && s->cert->cert_cb != NULL) {
2263                 int rv = s->cert->cert_cb(s, s->cert->cert_cb_arg);
2264                 if (rv == 0) {
2265                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2266                              SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
2267                              SSL_R_CERT_CB_ERROR);
2268                     goto err;
2269                 }
2270                 if (rv < 0) {
2271                     s->rwstate = SSL_X509_LOOKUP;
2272                     return WORK_MORE_B;
2273                 }
2274                 s->rwstate = SSL_NOTHING;
2275             }
2276 
2277             /* In TLSv1.3 we selected the ciphersuite before resumption */
2278             if (!SSL_IS_TLS13(s)) {
2279                 cipher =
2280                     ssl3_choose_cipher(s, s->peer_ciphers, SSL_get_ciphers(s));
2281 
2282                 if (cipher == NULL) {
2283                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2284                              SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
2285                              SSL_R_NO_SHARED_CIPHER);
2286                     goto err;
2287                 }
2288                 s->s3->tmp.new_cipher = cipher;
2289             }
2290             if (!s->hit) {
2291                 if (!tls_choose_sigalg(s, 1)) {
2292                     /* SSLfatal already called */
2293                     goto err;
2294                 }
2295                 /* check whether we should disable session resumption */
2296                 if (s->not_resumable_session_cb != NULL)
2297                     s->session->not_resumable =
2298                         s->not_resumable_session_cb(s,
2299                             ((s->s3->tmp.new_cipher->algorithm_mkey
2300                               & (SSL_kDHE | SSL_kECDHE)) != 0));
2301                 if (s->session->not_resumable)
2302                     /* do not send a session ticket */
2303                     s->ext.ticket_expected = 0;
2304             }
2305         } else {
2306             /* Session-id reuse */
2307             s->s3->tmp.new_cipher = s->session->cipher;
2308         }
2309 
2310         /*-
2311          * we now have the following setup.
2312          * client_random
2313          * cipher_list          - our preferred list of ciphers
2314          * ciphers              - the clients preferred list of ciphers
2315          * compression          - basically ignored right now
2316          * ssl version is set   - sslv3
2317          * s->session           - The ssl session has been setup.
2318          * s->hit               - session reuse flag
2319          * s->s3->tmp.new_cipher- the new cipher to use.
2320          */
2321 
2322         /*
2323          * Call status_request callback if needed. Has to be done after the
2324          * certificate callbacks etc above.
2325          */
2326         if (!tls_handle_status_request(s)) {
2327             /* SSLfatal() already called */
2328             goto err;
2329         }
2330         /*
2331          * Call alpn_select callback if needed.  Has to be done after SNI and
2332          * cipher negotiation (HTTP/2 restricts permitted ciphers). In TLSv1.3
2333          * we already did this because cipher negotiation happens earlier, and
2334          * we must handle ALPN before we decide whether to accept early_data.
2335          */
2336         if (!SSL_IS_TLS13(s) && !tls_handle_alpn(s)) {
2337             /* SSLfatal() already called */
2338             goto err;
2339         }
2340 
2341         wst = WORK_MORE_C;
2342     }
2343 #ifndef OPENSSL_NO_SRP
2344     if (wst == WORK_MORE_C) {
2345         int ret;
2346         if ((ret = ssl_check_srp_ext_ClientHello(s)) == 0) {
2347             /*
2348              * callback indicates further work to be done
2349              */
2350             s->rwstate = SSL_X509_LOOKUP;
2351             return WORK_MORE_C;
2352         }
2353         if (ret < 0) {
2354             /* SSLfatal() already called */
2355             goto err;
2356         }
2357     }
2358 #endif
2359 
2360     return WORK_FINISHED_STOP;
2361  err:
2362     return WORK_ERROR;
2363 }
2364 
2365 int tls_construct_server_hello(SSL *s, WPACKET *pkt)
2366 {
2367     int compm;
2368     size_t sl, len;
2369     int version;
2370     unsigned char *session_id;
2371     int usetls13 = SSL_IS_TLS13(s) || s->hello_retry_request == SSL_HRR_PENDING;
2372 
2373     version = usetls13 ? TLS1_2_VERSION : s->version;
2374     if (!WPACKET_put_bytes_u16(pkt, version)
2375                /*
2376                 * Random stuff. Filling of the server_random takes place in
2377                 * tls_process_client_hello()
2378                 */
2379             || !WPACKET_memcpy(pkt,
2380                                s->hello_retry_request == SSL_HRR_PENDING
2381                                    ? hrrrandom : s->s3->server_random,
2382                                SSL3_RANDOM_SIZE)) {
2383         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_SERVER_HELLO,
2384                  ERR_R_INTERNAL_ERROR);
2385         return 0;
2386     }
2387 
2388     /*-
2389      * There are several cases for the session ID to send
2390      * back in the server hello:
2391      * - For session reuse from the session cache,
2392      *   we send back the old session ID.
2393      * - If stateless session reuse (using a session ticket)
2394      *   is successful, we send back the client's "session ID"
2395      *   (which doesn't actually identify the session).
2396      * - If it is a new session, we send back the new
2397      *   session ID.
2398      * - However, if we want the new session to be single-use,
2399      *   we send back a 0-length session ID.
2400      * - In TLSv1.3 we echo back the session id sent to us by the client
2401      *   regardless
2402      * s->hit is non-zero in either case of session reuse,
2403      * so the following won't overwrite an ID that we're supposed
2404      * to send back.
2405      */
2406     if (s->session->not_resumable ||
2407         (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)
2408          && !s->hit))
2409         s->session->session_id_length = 0;
2410 
2411     if (usetls13) {
2412         sl = s->tmp_session_id_len;
2413         session_id = s->tmp_session_id;
2414     } else {
2415         sl = s->session->session_id_length;
2416         session_id = s->session->session_id;
2417     }
2418 
2419     if (sl > sizeof(s->session->session_id)) {
2420         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_SERVER_HELLO,
2421                  ERR_R_INTERNAL_ERROR);
2422         return 0;
2423     }
2424 
2425     /* set up the compression method */
2426 #ifdef OPENSSL_NO_COMP
2427     compm = 0;
2428 #else
2429     if (usetls13 || s->s3->tmp.new_compression == NULL)
2430         compm = 0;
2431     else
2432         compm = s->s3->tmp.new_compression->id;
2433 #endif
2434 
2435     if (!WPACKET_sub_memcpy_u8(pkt, session_id, sl)
2436             || !s->method->put_cipher_by_char(s->s3->tmp.new_cipher, pkt, &len)
2437             || !WPACKET_put_bytes_u8(pkt, compm)) {
2438         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_SERVER_HELLO,
2439                  ERR_R_INTERNAL_ERROR);
2440         return 0;
2441     }
2442 
2443     if (!tls_construct_extensions(s, pkt,
2444                                   s->hello_retry_request == SSL_HRR_PENDING
2445                                       ? SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
2446                                       : (SSL_IS_TLS13(s)
2447                                           ? SSL_EXT_TLS1_3_SERVER_HELLO
2448                                           : SSL_EXT_TLS1_2_SERVER_HELLO),
2449                                   NULL, 0)) {
2450         /* SSLfatal() already called */
2451         return 0;
2452     }
2453 
2454     if (s->hello_retry_request == SSL_HRR_PENDING) {
2455         /* Ditch the session. We'll create a new one next time around */
2456         SSL_SESSION_free(s->session);
2457         s->session = NULL;
2458         s->hit = 0;
2459 
2460         /*
2461          * Re-initialise the Transcript Hash. We're going to prepopulate it with
2462          * a synthetic message_hash in place of ClientHello1.
2463          */
2464         if (!create_synthetic_message_hash(s, NULL, 0, NULL, 0)) {
2465             /* SSLfatal() already called */
2466             return 0;
2467         }
2468     } else if (!(s->verify_mode & SSL_VERIFY_PEER)
2469                 && !ssl3_digest_cached_records(s, 0)) {
2470         /* SSLfatal() already called */;
2471         return 0;
2472     }
2473 
2474     return 1;
2475 }
2476 
2477 int tls_construct_server_done(SSL *s, WPACKET *pkt)
2478 {
2479     if (!s->s3->tmp.cert_request) {
2480         if (!ssl3_digest_cached_records(s, 0)) {
2481             /* SSLfatal() already called */
2482             return 0;
2483         }
2484     }
2485     return 1;
2486 }
2487 
2488 int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
2489 {
2490 #ifndef OPENSSL_NO_DH
2491     EVP_PKEY *pkdh = NULL;
2492 #endif
2493 #ifndef OPENSSL_NO_EC
2494     unsigned char *encodedPoint = NULL;
2495     size_t encodedlen = 0;
2496     int curve_id = 0;
2497 #endif
2498     const SIGALG_LOOKUP *lu = s->s3->tmp.sigalg;
2499     int i;
2500     unsigned long type;
2501     const BIGNUM *r[4];
2502     EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
2503     EVP_PKEY_CTX *pctx = NULL;
2504     size_t paramlen, paramoffset;
2505 
2506     if (!WPACKET_get_total_written(pkt, &paramoffset)) {
2507         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2508                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
2509         goto err;
2510     }
2511 
2512     if (md_ctx == NULL) {
2513         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2514                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
2515         goto err;
2516     }
2517 
2518     type = s->s3->tmp.new_cipher->algorithm_mkey;
2519 
2520     r[0] = r[1] = r[2] = r[3] = NULL;
2521 #ifndef OPENSSL_NO_PSK
2522     /* Plain PSK or RSAPSK nothing to do */
2523     if (type & (SSL_kPSK | SSL_kRSAPSK)) {
2524     } else
2525 #endif                          /* !OPENSSL_NO_PSK */
2526 #ifndef OPENSSL_NO_DH
2527     if (type & (SSL_kDHE | SSL_kDHEPSK)) {
2528         CERT *cert = s->cert;
2529 
2530         EVP_PKEY *pkdhp = NULL;
2531         DH *dh;
2532 
2533         if (s->cert->dh_tmp_auto) {
2534             DH *dhp = ssl_get_auto_dh(s);
2535             pkdh = EVP_PKEY_new();
2536             if (pkdh == NULL || dhp == NULL) {
2537                 DH_free(dhp);
2538                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2539                          SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2540                          ERR_R_INTERNAL_ERROR);
2541                 goto err;
2542             }
2543             EVP_PKEY_assign_DH(pkdh, dhp);
2544             pkdhp = pkdh;
2545         } else {
2546             pkdhp = cert->dh_tmp;
2547         }
2548         if ((pkdhp == NULL) && (s->cert->dh_tmp_cb != NULL)) {
2549             DH *dhp = s->cert->dh_tmp_cb(s, 0, 1024);
2550             pkdh = ssl_dh_to_pkey(dhp);
2551             if (pkdh == NULL) {
2552                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2553                          SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2554                          ERR_R_INTERNAL_ERROR);
2555                 goto err;
2556             }
2557             pkdhp = pkdh;
2558         }
2559         if (pkdhp == NULL) {
2560             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2561                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2562                      SSL_R_MISSING_TMP_DH_KEY);
2563             goto err;
2564         }
2565         if (!ssl_security(s, SSL_SECOP_TMP_DH,
2566                           EVP_PKEY_security_bits(pkdhp), 0, pkdhp)) {
2567             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2568                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2569                      SSL_R_DH_KEY_TOO_SMALL);
2570             goto err;
2571         }
2572         if (s->s3->tmp.pkey != NULL) {
2573             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2574                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2575                      ERR_R_INTERNAL_ERROR);
2576             goto err;
2577         }
2578 
2579         s->s3->tmp.pkey = ssl_generate_pkey(pkdhp);
2580         if (s->s3->tmp.pkey == NULL) {
2581             SSLfatal(s, SSL_AD_INTERNAL_ERROR, 0, ERR_R_INTERNAL_ERROR);
2582             goto err;
2583         }
2584 
2585         dh = EVP_PKEY_get0_DH(s->s3->tmp.pkey);
2586         if (dh == NULL) {
2587             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2588                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2589                      ERR_R_INTERNAL_ERROR);
2590             goto err;
2591         }
2592 
2593         EVP_PKEY_free(pkdh);
2594         pkdh = NULL;
2595 
2596         DH_get0_pqg(dh, &r[0], NULL, &r[1]);
2597         DH_get0_key(dh, &r[2], NULL);
2598     } else
2599 #endif
2600 #ifndef OPENSSL_NO_EC
2601     if (type & (SSL_kECDHE | SSL_kECDHEPSK)) {
2602 
2603         if (s->s3->tmp.pkey != NULL) {
2604             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2605                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2606                      ERR_R_INTERNAL_ERROR);
2607             goto err;
2608         }
2609 
2610         /* Get NID of appropriate shared curve */
2611         curve_id = tls1_shared_group(s, -2);
2612         if (curve_id == 0) {
2613             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
2614                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2615                      SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
2616             goto err;
2617         }
2618         s->s3->tmp.pkey = ssl_generate_pkey_group(s, curve_id);
2619         /* Generate a new key for this curve */
2620         if (s->s3->tmp.pkey == NULL) {
2621             /* SSLfatal() already called */
2622             goto err;
2623         }
2624 
2625         /* Encode the public key. */
2626         encodedlen = EVP_PKEY_get1_tls_encodedpoint(s->s3->tmp.pkey,
2627                                                     &encodedPoint);
2628         if (encodedlen == 0) {
2629             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2630                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_EC_LIB);
2631             goto err;
2632         }
2633 
2634         /*
2635          * We'll generate the serverKeyExchange message explicitly so we
2636          * can set these to NULLs
2637          */
2638         r[0] = NULL;
2639         r[1] = NULL;
2640         r[2] = NULL;
2641         r[3] = NULL;
2642     } else
2643 #endif                          /* !OPENSSL_NO_EC */
2644 #ifndef OPENSSL_NO_SRP
2645     if (type & SSL_kSRP) {
2646         if ((s->srp_ctx.N == NULL) ||
2647             (s->srp_ctx.g == NULL) ||
2648             (s->srp_ctx.s == NULL) || (s->srp_ctx.B == NULL)) {
2649             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2650                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2651                      SSL_R_MISSING_SRP_PARAM);
2652             goto err;
2653         }
2654         r[0] = s->srp_ctx.N;
2655         r[1] = s->srp_ctx.g;
2656         r[2] = s->srp_ctx.s;
2657         r[3] = s->srp_ctx.B;
2658     } else
2659 #endif
2660     {
2661         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2662                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2663                  SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
2664         goto err;
2665     }
2666 
2667     if (((s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aSRP)) != 0)
2668         || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) != 0) {
2669         lu = NULL;
2670     } else if (lu == NULL) {
2671         SSLfatal(s, SSL_AD_DECODE_ERROR,
2672                  SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
2673         goto err;
2674     }
2675 
2676 #ifndef OPENSSL_NO_PSK
2677     if (type & SSL_PSK) {
2678         size_t len = (s->cert->psk_identity_hint == NULL)
2679                         ? 0 : strlen(s->cert->psk_identity_hint);
2680 
2681         /*
2682          * It should not happen that len > PSK_MAX_IDENTITY_LEN - we already
2683          * checked this when we set the identity hint - but just in case
2684          */
2685         if (len > PSK_MAX_IDENTITY_LEN
2686                 || !WPACKET_sub_memcpy_u16(pkt, s->cert->psk_identity_hint,
2687                                            len)) {
2688             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2689                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2690                      ERR_R_INTERNAL_ERROR);
2691             goto err;
2692         }
2693     }
2694 #endif
2695 
2696     for (i = 0; i < 4 && r[i] != NULL; i++) {
2697         unsigned char *binval;
2698         int res;
2699 
2700 #ifndef OPENSSL_NO_SRP
2701         if ((i == 2) && (type & SSL_kSRP)) {
2702             res = WPACKET_start_sub_packet_u8(pkt);
2703         } else
2704 #endif
2705             res = WPACKET_start_sub_packet_u16(pkt);
2706 
2707         if (!res) {
2708             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2709                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2710                      ERR_R_INTERNAL_ERROR);
2711             goto err;
2712         }
2713 
2714 #ifndef OPENSSL_NO_DH
2715         /*-
2716          * for interoperability with some versions of the Microsoft TLS
2717          * stack, we need to zero pad the DHE pub key to the same length
2718          * as the prime
2719          */
2720         if ((i == 2) && (type & (SSL_kDHE | SSL_kDHEPSK))) {
2721             size_t len = BN_num_bytes(r[0]) - BN_num_bytes(r[2]);
2722 
2723             if (len > 0) {
2724                 if (!WPACKET_allocate_bytes(pkt, len, &binval)) {
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                 memset(binval, 0, len);
2731             }
2732         }
2733 #endif
2734         if (!WPACKET_allocate_bytes(pkt, BN_num_bytes(r[i]), &binval)
2735                 || !WPACKET_close(pkt)) {
2736             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2737                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2738                      ERR_R_INTERNAL_ERROR);
2739             goto err;
2740         }
2741 
2742         BN_bn2bin(r[i], binval);
2743     }
2744 
2745 #ifndef OPENSSL_NO_EC
2746     if (type & (SSL_kECDHE | SSL_kECDHEPSK)) {
2747         /*
2748          * We only support named (not generic) curves. In this situation, the
2749          * ServerKeyExchange message has: [1 byte CurveType], [2 byte CurveName]
2750          * [1 byte length of encoded point], followed by the actual encoded
2751          * point itself
2752          */
2753         if (!WPACKET_put_bytes_u8(pkt, NAMED_CURVE_TYPE)
2754                 || !WPACKET_put_bytes_u8(pkt, 0)
2755                 || !WPACKET_put_bytes_u8(pkt, curve_id)
2756                 || !WPACKET_sub_memcpy_u8(pkt, encodedPoint, encodedlen)) {
2757             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2758                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2759                      ERR_R_INTERNAL_ERROR);
2760             goto err;
2761         }
2762         OPENSSL_free(encodedPoint);
2763         encodedPoint = NULL;
2764     }
2765 #endif
2766 
2767     /* not anonymous */
2768     if (lu != NULL) {
2769         EVP_PKEY *pkey = s->s3->tmp.cert->privatekey;
2770         const EVP_MD *md;
2771         unsigned char *sigbytes1, *sigbytes2, *tbs;
2772         size_t siglen, tbslen;
2773         int rv;
2774 
2775         if (pkey == NULL || !tls1_lookup_md(lu, &md)) {
2776             /* Should never happen */
2777             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2778                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2779                      ERR_R_INTERNAL_ERROR);
2780             goto err;
2781         }
2782         /* Get length of the parameters we have written above */
2783         if (!WPACKET_get_length(pkt, &paramlen)) {
2784             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2785                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2786                      ERR_R_INTERNAL_ERROR);
2787             goto err;
2788         }
2789         /* send signature algorithm */
2790         if (SSL_USE_SIGALGS(s) && !WPACKET_put_bytes_u16(pkt, lu->sigalg)) {
2791             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2792                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2793                      ERR_R_INTERNAL_ERROR);
2794             goto err;
2795         }
2796         /*
2797          * Create the signature. We don't know the actual length of the sig
2798          * until after we've created it, so we reserve enough bytes for it
2799          * up front, and then properly allocate them in the WPACKET
2800          * afterwards.
2801          */
2802         siglen = EVP_PKEY_size(pkey);
2803         if (!WPACKET_sub_reserve_bytes_u16(pkt, siglen, &sigbytes1)
2804             || EVP_DigestSignInit(md_ctx, &pctx, md, NULL, pkey) <= 0) {
2805             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2806                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2807                      ERR_R_INTERNAL_ERROR);
2808             goto err;
2809         }
2810         if (lu->sig == EVP_PKEY_RSA_PSS) {
2811             if (EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) <= 0
2812                 || EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST) <= 0) {
2813                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2814                          SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2815                         ERR_R_EVP_LIB);
2816                 goto err;
2817             }
2818         }
2819         tbslen = construct_key_exchange_tbs(s, &tbs,
2820                                             s->init_buf->data + paramoffset,
2821                                             paramlen);
2822         if (tbslen == 0) {
2823             /* SSLfatal() already called */
2824             goto err;
2825         }
2826         rv = EVP_DigestSign(md_ctx, sigbytes1, &siglen, tbs, tbslen);
2827         OPENSSL_free(tbs);
2828         if (rv <= 0 || !WPACKET_sub_allocate_bytes_u16(pkt, siglen, &sigbytes2)
2829             || sigbytes1 != sigbytes2) {
2830             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2831                      SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
2832                      ERR_R_INTERNAL_ERROR);
2833             goto err;
2834         }
2835     }
2836 
2837     EVP_MD_CTX_free(md_ctx);
2838     return 1;
2839  err:
2840 #ifndef OPENSSL_NO_DH
2841     EVP_PKEY_free(pkdh);
2842 #endif
2843 #ifndef OPENSSL_NO_EC
2844     OPENSSL_free(encodedPoint);
2845 #endif
2846     EVP_MD_CTX_free(md_ctx);
2847     return 0;
2848 }
2849 
2850 int tls_construct_certificate_request(SSL *s, WPACKET *pkt)
2851 {
2852     if (SSL_IS_TLS13(s)) {
2853         /* Send random context when doing post-handshake auth */
2854         if (s->post_handshake_auth == SSL_PHA_REQUEST_PENDING) {
2855             OPENSSL_free(s->pha_context);
2856             s->pha_context_len = 32;
2857             if ((s->pha_context = OPENSSL_malloc(s->pha_context_len)) == NULL) {
2858                 s->pha_context_len = 0;
2859                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2860                          SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2861                          ERR_R_INTERNAL_ERROR);
2862                 return 0;
2863             }
2864             if (RAND_bytes(s->pha_context, s->pha_context_len) <= 0
2865                     || !WPACKET_sub_memcpy_u8(pkt, s->pha_context,
2866                                               s->pha_context_len)) {
2867                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2868                          SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2869                          ERR_R_INTERNAL_ERROR);
2870                 return 0;
2871             }
2872             /* reset the handshake hash back to just after the ClientFinished */
2873             if (!tls13_restore_handshake_digest_for_pha(s)) {
2874                 /* SSLfatal() already called */
2875                 return 0;
2876             }
2877         } else {
2878             if (!WPACKET_put_bytes_u8(pkt, 0)) {
2879                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2880                          SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2881                          ERR_R_INTERNAL_ERROR);
2882                 return 0;
2883             }
2884         }
2885 
2886         if (!tls_construct_extensions(s, pkt,
2887                                       SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, NULL,
2888                                       0)) {
2889             /* SSLfatal() already called */
2890             return 0;
2891         }
2892         goto done;
2893     }
2894 
2895     /* get the list of acceptable cert types */
2896     if (!WPACKET_start_sub_packet_u8(pkt)
2897         || !ssl3_get_req_cert_type(s, pkt) || !WPACKET_close(pkt)) {
2898         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2899                  SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST, ERR_R_INTERNAL_ERROR);
2900         return 0;
2901     }
2902 
2903     if (SSL_USE_SIGALGS(s)) {
2904         const uint16_t *psigs;
2905         size_t nl = tls12_get_psigalgs(s, 1, &psigs);
2906 
2907         if (!WPACKET_start_sub_packet_u16(pkt)
2908                 || !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)
2909                 || !tls12_copy_sigalgs(s, pkt, psigs, nl)
2910                 || !WPACKET_close(pkt)) {
2911             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2912                      SSL_F_TLS_CONSTRUCT_CERTIFICATE_REQUEST,
2913                      ERR_R_INTERNAL_ERROR);
2914             return 0;
2915         }
2916     }
2917 
2918     if (!construct_ca_names(s, get_ca_names(s), pkt)) {
2919         /* SSLfatal() already called */
2920         return 0;
2921     }
2922 
2923  done:
2924     s->certreqs_sent++;
2925     s->s3->tmp.cert_request = 1;
2926     return 1;
2927 }
2928 
2929 static int tls_process_cke_psk_preamble(SSL *s, PACKET *pkt)
2930 {
2931 #ifndef OPENSSL_NO_PSK
2932     unsigned char psk[PSK_MAX_PSK_LEN];
2933     size_t psklen;
2934     PACKET psk_identity;
2935 
2936     if (!PACKET_get_length_prefixed_2(pkt, &psk_identity)) {
2937         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2938                  SSL_R_LENGTH_MISMATCH);
2939         return 0;
2940     }
2941     if (PACKET_remaining(&psk_identity) > PSK_MAX_IDENTITY_LEN) {
2942         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2943                  SSL_R_DATA_LENGTH_TOO_LONG);
2944         return 0;
2945     }
2946     if (s->psk_server_callback == NULL) {
2947         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2948                  SSL_R_PSK_NO_SERVER_CB);
2949         return 0;
2950     }
2951 
2952     if (!PACKET_strndup(&psk_identity, &s->session->psk_identity)) {
2953         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2954                  ERR_R_INTERNAL_ERROR);
2955         return 0;
2956     }
2957 
2958     psklen = s->psk_server_callback(s, s->session->psk_identity,
2959                                     psk, sizeof(psk));
2960 
2961     if (psklen > PSK_MAX_PSK_LEN) {
2962         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2963                  ERR_R_INTERNAL_ERROR);
2964         return 0;
2965     } else if (psklen == 0) {
2966         /*
2967          * PSK related to the given identity not found
2968          */
2969         SSLfatal(s, SSL_AD_UNKNOWN_PSK_IDENTITY,
2970                  SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2971                  SSL_R_PSK_IDENTITY_NOT_FOUND);
2972         return 0;
2973     }
2974 
2975     OPENSSL_free(s->s3->tmp.psk);
2976     s->s3->tmp.psk = OPENSSL_memdup(psk, psklen);
2977     OPENSSL_cleanse(psk, psklen);
2978 
2979     if (s->s3->tmp.psk == NULL) {
2980         s->s3->tmp.psklen = 0;
2981         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
2982                  SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE, ERR_R_MALLOC_FAILURE);
2983         return 0;
2984     }
2985 
2986     s->s3->tmp.psklen = psklen;
2987 
2988     return 1;
2989 #else
2990     /* Should never happen */
2991     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_PSK_PREAMBLE,
2992              ERR_R_INTERNAL_ERROR);
2993     return 0;
2994 #endif
2995 }
2996 
2997 static int tls_process_cke_rsa(SSL *s, PACKET *pkt)
2998 {
2999 #ifndef OPENSSL_NO_RSA
3000     unsigned char rand_premaster_secret[SSL_MAX_MASTER_KEY_LENGTH];
3001     int decrypt_len;
3002     unsigned char decrypt_good, version_good;
3003     size_t j, padding_len;
3004     PACKET enc_premaster;
3005     RSA *rsa = NULL;
3006     unsigned char *rsa_decrypt = NULL;
3007     int ret = 0;
3008 
3009     rsa = EVP_PKEY_get0_RSA(s->cert->pkeys[SSL_PKEY_RSA].privatekey);
3010     if (rsa == NULL) {
3011         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3012                  SSL_R_MISSING_RSA_CERTIFICATE);
3013         return 0;
3014     }
3015 
3016     /* SSLv3 and pre-standard DTLS omit the length bytes. */
3017     if (s->version == SSL3_VERSION || s->version == DTLS1_BAD_VER) {
3018         enc_premaster = *pkt;
3019     } else {
3020         if (!PACKET_get_length_prefixed_2(pkt, &enc_premaster)
3021             || PACKET_remaining(pkt) != 0) {
3022             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3023                      SSL_R_LENGTH_MISMATCH);
3024             return 0;
3025         }
3026     }
3027 
3028     /*
3029      * We want to be sure that the plaintext buffer size makes it safe to
3030      * iterate over the entire size of a premaster secret
3031      * (SSL_MAX_MASTER_KEY_LENGTH). Reject overly short RSA keys because
3032      * their ciphertext cannot accommodate a premaster secret anyway.
3033      */
3034     if (RSA_size(rsa) < SSL_MAX_MASTER_KEY_LENGTH) {
3035         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3036                  RSA_R_KEY_SIZE_TOO_SMALL);
3037         return 0;
3038     }
3039 
3040     rsa_decrypt = OPENSSL_malloc(RSA_size(rsa));
3041     if (rsa_decrypt == NULL) {
3042         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3043                  ERR_R_MALLOC_FAILURE);
3044         return 0;
3045     }
3046 
3047     /*
3048      * We must not leak whether a decryption failure occurs because of
3049      * Bleichenbacher's attack on PKCS #1 v1.5 RSA padding (see RFC 2246,
3050      * section 7.4.7.1). The code follows that advice of the TLS RFC and
3051      * generates a random premaster secret for the case that the decrypt
3052      * fails. See https://tools.ietf.org/html/rfc5246#section-7.4.7.1
3053      */
3054 
3055     if (RAND_priv_bytes(rand_premaster_secret,
3056                       sizeof(rand_premaster_secret)) <= 0) {
3057         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3058                  ERR_R_INTERNAL_ERROR);
3059         goto err;
3060     }
3061 
3062     /*
3063      * Decrypt with no padding. PKCS#1 padding will be removed as part of
3064      * the timing-sensitive code below.
3065      */
3066      /* TODO(size_t): Convert this function */
3067     decrypt_len = (int)RSA_private_decrypt((int)PACKET_remaining(&enc_premaster),
3068                                            PACKET_data(&enc_premaster),
3069                                            rsa_decrypt, rsa, RSA_NO_PADDING);
3070     if (decrypt_len < 0) {
3071         SSLfatal(s, SSL_AD_DECRYPT_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3072                  ERR_R_INTERNAL_ERROR);
3073         goto err;
3074     }
3075 
3076     /* Check the padding. See RFC 3447, section 7.2.2. */
3077 
3078     /*
3079      * The smallest padded premaster is 11 bytes of overhead. Small keys
3080      * are publicly invalid, so this may return immediately. This ensures
3081      * PS is at least 8 bytes.
3082      */
3083     if (decrypt_len < 11 + SSL_MAX_MASTER_KEY_LENGTH) {
3084         SSLfatal(s, SSL_AD_DECRYPT_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3085                  SSL_R_DECRYPTION_FAILED);
3086         goto err;
3087     }
3088 
3089     padding_len = decrypt_len - SSL_MAX_MASTER_KEY_LENGTH;
3090     decrypt_good = constant_time_eq_int_8(rsa_decrypt[0], 0) &
3091         constant_time_eq_int_8(rsa_decrypt[1], 2);
3092     for (j = 2; j < padding_len - 1; j++) {
3093         decrypt_good &= ~constant_time_is_zero_8(rsa_decrypt[j]);
3094     }
3095     decrypt_good &= constant_time_is_zero_8(rsa_decrypt[padding_len - 1]);
3096 
3097     /*
3098      * If the version in the decrypted pre-master secret is correct then
3099      * version_good will be 0xff, otherwise it'll be zero. The
3100      * Klima-Pokorny-Rosa extension of Bleichenbacher's attack
3101      * (http://eprint.iacr.org/2003/052/) exploits the version number
3102      * check as a "bad version oracle". Thus version checks are done in
3103      * constant time and are treated like any other decryption error.
3104      */
3105     version_good =
3106         constant_time_eq_8(rsa_decrypt[padding_len],
3107                            (unsigned)(s->client_version >> 8));
3108     version_good &=
3109         constant_time_eq_8(rsa_decrypt[padding_len + 1],
3110                            (unsigned)(s->client_version & 0xff));
3111 
3112     /*
3113      * The premaster secret must contain the same version number as the
3114      * ClientHello to detect version rollback attacks (strangely, the
3115      * protocol does not offer such protection for DH ciphersuites).
3116      * However, buggy clients exist that send the negotiated protocol
3117      * version instead if the server does not support the requested
3118      * protocol version. If SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such
3119      * clients.
3120      */
3121     if (s->options & SSL_OP_TLS_ROLLBACK_BUG) {
3122         unsigned char workaround_good;
3123         workaround_good = constant_time_eq_8(rsa_decrypt[padding_len],
3124                                              (unsigned)(s->version >> 8));
3125         workaround_good &=
3126             constant_time_eq_8(rsa_decrypt[padding_len + 1],
3127                                (unsigned)(s->version & 0xff));
3128         version_good |= workaround_good;
3129     }
3130 
3131     /*
3132      * Both decryption and version must be good for decrypt_good to
3133      * remain non-zero (0xff).
3134      */
3135     decrypt_good &= version_good;
3136 
3137     /*
3138      * Now copy rand_premaster_secret over from p using
3139      * decrypt_good_mask. If decryption failed, then p does not
3140      * contain valid plaintext, however, a check above guarantees
3141      * it is still sufficiently large to read from.
3142      */
3143     for (j = 0; j < sizeof(rand_premaster_secret); j++) {
3144         rsa_decrypt[padding_len + j] =
3145             constant_time_select_8(decrypt_good,
3146                                    rsa_decrypt[padding_len + j],
3147                                    rand_premaster_secret[j]);
3148     }
3149 
3150     if (!ssl_generate_master_secret(s, rsa_decrypt + padding_len,
3151                                     sizeof(rand_premaster_secret), 0)) {
3152         /* SSLfatal() already called */
3153         goto err;
3154     }
3155 
3156     ret = 1;
3157  err:
3158     OPENSSL_free(rsa_decrypt);
3159     return ret;
3160 #else
3161     /* Should never happen */
3162     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_RSA,
3163              ERR_R_INTERNAL_ERROR);
3164     return 0;
3165 #endif
3166 }
3167 
3168 static int tls_process_cke_dhe(SSL *s, PACKET *pkt)
3169 {
3170 #ifndef OPENSSL_NO_DH
3171     EVP_PKEY *skey = NULL;
3172     DH *cdh;
3173     unsigned int i;
3174     BIGNUM *pub_key;
3175     const unsigned char *data;
3176     EVP_PKEY *ckey = NULL;
3177     int ret = 0;
3178 
3179     if (!PACKET_get_net_2(pkt, &i) || PACKET_remaining(pkt) != i) {
3180         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3181                SSL_R_DH_PUBLIC_VALUE_LENGTH_IS_WRONG);
3182         goto err;
3183     }
3184     skey = s->s3->tmp.pkey;
3185     if (skey == NULL) {
3186         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3187                  SSL_R_MISSING_TMP_DH_KEY);
3188         goto err;
3189     }
3190 
3191     if (PACKET_remaining(pkt) == 0L) {
3192         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3193                  SSL_R_MISSING_TMP_DH_KEY);
3194         goto err;
3195     }
3196     if (!PACKET_get_bytes(pkt, &data, i)) {
3197         /* We already checked we have enough data */
3198         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3199                  ERR_R_INTERNAL_ERROR);
3200         goto err;
3201     }
3202     ckey = EVP_PKEY_new();
3203     if (ckey == NULL || EVP_PKEY_copy_parameters(ckey, skey) == 0) {
3204         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3205                  SSL_R_BN_LIB);
3206         goto err;
3207     }
3208 
3209     cdh = EVP_PKEY_get0_DH(ckey);
3210     pub_key = BN_bin2bn(data, i, NULL);
3211     if (pub_key == NULL || cdh == NULL || !DH_set0_key(cdh, pub_key, NULL)) {
3212         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3213                  ERR_R_INTERNAL_ERROR);
3214         BN_free(pub_key);
3215         goto err;
3216     }
3217 
3218     if (ssl_derive(s, skey, ckey, 1) == 0) {
3219         /* SSLfatal() already called */
3220         goto err;
3221     }
3222 
3223     ret = 1;
3224     EVP_PKEY_free(s->s3->tmp.pkey);
3225     s->s3->tmp.pkey = NULL;
3226  err:
3227     EVP_PKEY_free(ckey);
3228     return ret;
3229 #else
3230     /* Should never happen */
3231     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_DHE,
3232              ERR_R_INTERNAL_ERROR);
3233     return 0;
3234 #endif
3235 }
3236 
3237 static int tls_process_cke_ecdhe(SSL *s, PACKET *pkt)
3238 {
3239 #ifndef OPENSSL_NO_EC
3240     EVP_PKEY *skey = s->s3->tmp.pkey;
3241     EVP_PKEY *ckey = NULL;
3242     int ret = 0;
3243 
3244     if (PACKET_remaining(pkt) == 0L) {
3245         /* We don't support ECDH client auth */
3246         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PROCESS_CKE_ECDHE,
3247                  SSL_R_MISSING_TMP_ECDH_KEY);
3248         goto err;
3249     } else {
3250         unsigned int i;
3251         const unsigned char *data;
3252 
3253         /*
3254          * Get client's public key from encoded point in the
3255          * ClientKeyExchange message.
3256          */
3257 
3258         /* Get encoded point length */
3259         if (!PACKET_get_1(pkt, &i) || !PACKET_get_bytes(pkt, &data, i)
3260             || PACKET_remaining(pkt) != 0) {
3261             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3262                      SSL_R_LENGTH_MISMATCH);
3263             goto err;
3264         }
3265         if (skey == NULL) {
3266             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3267                      SSL_R_MISSING_TMP_ECDH_KEY);
3268             goto err;
3269         }
3270 
3271         ckey = EVP_PKEY_new();
3272         if (ckey == NULL || EVP_PKEY_copy_parameters(ckey, skey) <= 0) {
3273             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3274                      ERR_R_EVP_LIB);
3275             goto err;
3276         }
3277         if (EVP_PKEY_set1_tls_encodedpoint(ckey, data, i) == 0) {
3278             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3279                      ERR_R_EC_LIB);
3280             goto err;
3281         }
3282     }
3283 
3284     if (ssl_derive(s, skey, ckey, 1) == 0) {
3285         /* SSLfatal() already called */
3286         goto err;
3287     }
3288 
3289     ret = 1;
3290     EVP_PKEY_free(s->s3->tmp.pkey);
3291     s->s3->tmp.pkey = NULL;
3292  err:
3293     EVP_PKEY_free(ckey);
3294 
3295     return ret;
3296 #else
3297     /* Should never happen */
3298     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_ECDHE,
3299              ERR_R_INTERNAL_ERROR);
3300     return 0;
3301 #endif
3302 }
3303 
3304 static int tls_process_cke_srp(SSL *s, PACKET *pkt)
3305 {
3306 #ifndef OPENSSL_NO_SRP
3307     unsigned int i;
3308     const unsigned char *data;
3309 
3310     if (!PACKET_get_net_2(pkt, &i)
3311         || !PACKET_get_bytes(pkt, &data, i)) {
3312         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3313                  SSL_R_BAD_SRP_A_LENGTH);
3314         return 0;
3315     }
3316     if ((s->srp_ctx.A = BN_bin2bn(data, i, NULL)) == NULL) {
3317         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3318                  ERR_R_BN_LIB);
3319         return 0;
3320     }
3321     if (BN_ucmp(s->srp_ctx.A, s->srp_ctx.N) >= 0 || BN_is_zero(s->srp_ctx.A)) {
3322         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PROCESS_CKE_SRP,
3323                  SSL_R_BAD_SRP_PARAMETERS);
3324         return 0;
3325     }
3326     OPENSSL_free(s->session->srp_username);
3327     s->session->srp_username = OPENSSL_strdup(s->srp_ctx.login);
3328     if (s->session->srp_username == NULL) {
3329         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3330                  ERR_R_MALLOC_FAILURE);
3331         return 0;
3332     }
3333 
3334     if (!srp_generate_server_master_secret(s)) {
3335         /* SSLfatal() already called */
3336         return 0;
3337     }
3338 
3339     return 1;
3340 #else
3341     /* Should never happen */
3342     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_SRP,
3343              ERR_R_INTERNAL_ERROR);
3344     return 0;
3345 #endif
3346 }
3347 
3348 static int tls_process_cke_gost(SSL *s, PACKET *pkt)
3349 {
3350 #ifndef OPENSSL_NO_GOST
3351     EVP_PKEY_CTX *pkey_ctx;
3352     EVP_PKEY *client_pub_pkey = NULL, *pk = NULL;
3353     unsigned char premaster_secret[32];
3354     const unsigned char *start;
3355     size_t outlen = 32, inlen;
3356     unsigned long alg_a;
3357     GOST_KX_MESSAGE *pKX = NULL;
3358     const unsigned char *ptr;
3359     int ret = 0;
3360 
3361     /* Get our certificate private key */
3362     alg_a = s->s3->tmp.new_cipher->algorithm_auth;
3363     if (alg_a & SSL_aGOST12) {
3364         /*
3365          * New GOST ciphersuites have SSL_aGOST01 bit too
3366          */
3367         pk = s->cert->pkeys[SSL_PKEY_GOST12_512].privatekey;
3368         if (pk == NULL) {
3369             pk = s->cert->pkeys[SSL_PKEY_GOST12_256].privatekey;
3370         }
3371         if (pk == NULL) {
3372             pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
3373         }
3374     } else if (alg_a & SSL_aGOST01) {
3375         pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;
3376     }
3377 
3378     pkey_ctx = EVP_PKEY_CTX_new(pk, NULL);
3379     if (pkey_ctx == NULL) {
3380         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3381                  ERR_R_MALLOC_FAILURE);
3382         return 0;
3383     }
3384     if (EVP_PKEY_decrypt_init(pkey_ctx) <= 0) {
3385         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3386                  ERR_R_INTERNAL_ERROR);
3387         return 0;
3388     }
3389     /*
3390      * If client certificate is present and is of the same type, maybe
3391      * use it for key exchange.  Don't mind errors from
3392      * EVP_PKEY_derive_set_peer, because it is completely valid to use a
3393      * client certificate for authorization only.
3394      */
3395     client_pub_pkey = X509_get0_pubkey(s->session->peer);
3396     if (client_pub_pkey) {
3397         if (EVP_PKEY_derive_set_peer(pkey_ctx, client_pub_pkey) <= 0)
3398             ERR_clear_error();
3399     }
3400 
3401     ptr = PACKET_data(pkt);
3402     /* Some implementations provide extra data in the opaqueBlob
3403      * We have nothing to do with this blob so we just skip it */
3404     pKX = d2i_GOST_KX_MESSAGE(NULL, &ptr, PACKET_remaining(pkt));
3405     if (pKX == NULL
3406        || pKX->kxBlob == NULL
3407        || ASN1_TYPE_get(pKX->kxBlob) != V_ASN1_SEQUENCE) {
3408          SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3409                   SSL_R_DECRYPTION_FAILED);
3410          goto err;
3411     }
3412 
3413     if (!PACKET_forward(pkt, ptr - PACKET_data(pkt))) {
3414         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3415                  SSL_R_DECRYPTION_FAILED);
3416         goto err;
3417     }
3418 
3419     if (PACKET_remaining(pkt) != 0) {
3420         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3421                  SSL_R_DECRYPTION_FAILED);
3422         goto err;
3423     }
3424 
3425     inlen = pKX->kxBlob->value.sequence->length;
3426     start = pKX->kxBlob->value.sequence->data;
3427 
3428     if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen, start,
3429                          inlen) <= 0) {
3430         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3431                  SSL_R_DECRYPTION_FAILED);
3432         goto err;
3433     }
3434     /* Generate master secret */
3435     if (!ssl_generate_master_secret(s, premaster_secret,
3436                                     sizeof(premaster_secret), 0)) {
3437         /* SSLfatal() already called */
3438         goto err;
3439     }
3440     /* Check if pubkey from client certificate was used */
3441     if (EVP_PKEY_CTX_ctrl(pkey_ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 2,
3442                           NULL) > 0)
3443         s->statem.no_cert_verify = 1;
3444 
3445     ret = 1;
3446  err:
3447     EVP_PKEY_CTX_free(pkey_ctx);
3448     GOST_KX_MESSAGE_free(pKX);
3449     return ret;
3450 #else
3451     /* Should never happen */
3452     SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
3453              ERR_R_INTERNAL_ERROR);
3454     return 0;
3455 #endif
3456 }
3457 
3458 MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
3459 {
3460     unsigned long alg_k;
3461 
3462     alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
3463 
3464     /* For PSK parse and retrieve identity, obtain PSK key */
3465     if ((alg_k & SSL_PSK) && !tls_process_cke_psk_preamble(s, pkt)) {
3466         /* SSLfatal() already called */
3467         goto err;
3468     }
3469 
3470     if (alg_k & SSL_kPSK) {
3471         /* Identity extracted earlier: should be nothing left */
3472         if (PACKET_remaining(pkt) != 0) {
3473             SSLfatal(s, SSL_AD_DECODE_ERROR,
3474                      SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE,
3475                      SSL_R_LENGTH_MISMATCH);
3476             goto err;
3477         }
3478         /* PSK handled by ssl_generate_master_secret */
3479         if (!ssl_generate_master_secret(s, NULL, 0, 0)) {
3480             /* SSLfatal() already called */
3481             goto err;
3482         }
3483     } else if (alg_k & (SSL_kRSA | SSL_kRSAPSK)) {
3484         if (!tls_process_cke_rsa(s, pkt)) {
3485             /* SSLfatal() already called */
3486             goto err;
3487         }
3488     } else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
3489         if (!tls_process_cke_dhe(s, pkt)) {
3490             /* SSLfatal() already called */
3491             goto err;
3492         }
3493     } else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
3494         if (!tls_process_cke_ecdhe(s, pkt)) {
3495             /* SSLfatal() already called */
3496             goto err;
3497         }
3498     } else if (alg_k & SSL_kSRP) {
3499         if (!tls_process_cke_srp(s, pkt)) {
3500             /* SSLfatal() already called */
3501             goto err;
3502         }
3503     } else if (alg_k & SSL_kGOST) {
3504         if (!tls_process_cke_gost(s, pkt)) {
3505             /* SSLfatal() already called */
3506             goto err;
3507         }
3508     } else {
3509         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3510                  SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE,
3511                  SSL_R_UNKNOWN_CIPHER_TYPE);
3512         goto err;
3513     }
3514 
3515     return MSG_PROCESS_CONTINUE_PROCESSING;
3516  err:
3517 #ifndef OPENSSL_NO_PSK
3518     OPENSSL_clear_free(s->s3->tmp.psk, s->s3->tmp.psklen);
3519     s->s3->tmp.psk = NULL;
3520     s->s3->tmp.psklen = 0;
3521 #endif
3522     return MSG_PROCESS_ERROR;
3523 }
3524 
3525 WORK_STATE tls_post_process_client_key_exchange(SSL *s, WORK_STATE wst)
3526 {
3527 #ifndef OPENSSL_NO_SCTP
3528     if (wst == WORK_MORE_A) {
3529         if (SSL_IS_DTLS(s)) {
3530             unsigned char sctpauthkey[64];
3531             char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
3532             size_t labellen;
3533             /*
3534              * Add new shared key for SCTP-Auth, will be ignored if no SCTP
3535              * used.
3536              */
3537             memcpy(labelbuffer, DTLS1_SCTP_AUTH_LABEL,
3538                    sizeof(DTLS1_SCTP_AUTH_LABEL));
3539 
3540             /* Don't include the terminating zero. */
3541             labellen = sizeof(labelbuffer) - 1;
3542             if (s->mode & SSL_MODE_DTLS_SCTP_LABEL_LENGTH_BUG)
3543                 labellen += 1;
3544 
3545             if (SSL_export_keying_material(s, sctpauthkey,
3546                                            sizeof(sctpauthkey), labelbuffer,
3547                                            labellen, NULL, 0,
3548                                            0) <= 0) {
3549                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3550                          SSL_F_TLS_POST_PROCESS_CLIENT_KEY_EXCHANGE,
3551                          ERR_R_INTERNAL_ERROR);
3552                 return WORK_ERROR;
3553             }
3554 
3555             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
3556                      sizeof(sctpauthkey), sctpauthkey);
3557         }
3558     }
3559 #endif
3560 
3561     if (s->statem.no_cert_verify || !s->session->peer) {
3562         /*
3563          * No certificate verify or no peer certificate so we no longer need
3564          * the handshake_buffer
3565          */
3566         if (!ssl3_digest_cached_records(s, 0)) {
3567             /* SSLfatal() already called */
3568             return WORK_ERROR;
3569         }
3570         return WORK_FINISHED_CONTINUE;
3571     } else {
3572         if (!s->s3->handshake_buffer) {
3573             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3574                      SSL_F_TLS_POST_PROCESS_CLIENT_KEY_EXCHANGE,
3575                      ERR_R_INTERNAL_ERROR);
3576             return WORK_ERROR;
3577         }
3578         /*
3579          * For sigalgs freeze the handshake buffer. If we support
3580          * extms we've done this already so this is a no-op
3581          */
3582         if (!ssl3_digest_cached_records(s, 1)) {
3583             /* SSLfatal() already called */
3584             return WORK_ERROR;
3585         }
3586     }
3587 
3588     return WORK_FINISHED_CONTINUE;
3589 }
3590 
3591 MSG_PROCESS_RETURN tls_process_client_certificate(SSL *s, PACKET *pkt)
3592 {
3593     int i;
3594     MSG_PROCESS_RETURN ret = MSG_PROCESS_ERROR;
3595     X509 *x = NULL;
3596     unsigned long l;
3597     const unsigned char *certstart, *certbytes;
3598     STACK_OF(X509) *sk = NULL;
3599     PACKET spkt, context;
3600     size_t chainidx;
3601     SSL_SESSION *new_sess = NULL;
3602 
3603     /*
3604      * To get this far we must have read encrypted data from the client. We no
3605      * longer tolerate unencrypted alerts. This value is ignored if less than
3606      * TLSv1.3
3607      */
3608     s->statem.enc_read_state = ENC_READ_STATE_VALID;
3609 
3610     if ((sk = sk_X509_new_null()) == NULL) {
3611         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3612                  ERR_R_MALLOC_FAILURE);
3613         goto err;
3614     }
3615 
3616     if (SSL_IS_TLS13(s) && (!PACKET_get_length_prefixed_1(pkt, &context)
3617                             || (s->pha_context == NULL && PACKET_remaining(&context) != 0)
3618                             || (s->pha_context != NULL &&
3619                                 !PACKET_equal(&context, s->pha_context, s->pha_context_len)))) {
3620         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3621                  SSL_R_INVALID_CONTEXT);
3622         goto err;
3623     }
3624 
3625     if (!PACKET_get_length_prefixed_3(pkt, &spkt)
3626             || PACKET_remaining(pkt) != 0) {
3627         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3628                  SSL_R_LENGTH_MISMATCH);
3629         goto err;
3630     }
3631 
3632     for (chainidx = 0; PACKET_remaining(&spkt) > 0; chainidx++) {
3633         if (!PACKET_get_net_3(&spkt, &l)
3634             || !PACKET_get_bytes(&spkt, &certbytes, l)) {
3635             SSLfatal(s, SSL_AD_DECODE_ERROR,
3636                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3637                      SSL_R_CERT_LENGTH_MISMATCH);
3638             goto err;
3639         }
3640 
3641         certstart = certbytes;
3642         x = d2i_X509(NULL, (const unsigned char **)&certbytes, l);
3643         if (x == NULL) {
3644             SSLfatal(s, SSL_AD_DECODE_ERROR,
3645                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE, ERR_R_ASN1_LIB);
3646             goto err;
3647         }
3648         if (certbytes != (certstart + l)) {
3649             SSLfatal(s, SSL_AD_DECODE_ERROR,
3650                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3651                      SSL_R_CERT_LENGTH_MISMATCH);
3652             goto err;
3653         }
3654 
3655         if (SSL_IS_TLS13(s)) {
3656             RAW_EXTENSION *rawexts = NULL;
3657             PACKET extensions;
3658 
3659             if (!PACKET_get_length_prefixed_2(&spkt, &extensions)) {
3660                 SSLfatal(s, SSL_AD_DECODE_ERROR,
3661                          SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3662                          SSL_R_BAD_LENGTH);
3663                 goto err;
3664             }
3665             if (!tls_collect_extensions(s, &extensions,
3666                                         SSL_EXT_TLS1_3_CERTIFICATE, &rawexts,
3667                                         NULL, chainidx == 0)
3668                 || !tls_parse_all_extensions(s, SSL_EXT_TLS1_3_CERTIFICATE,
3669                                              rawexts, x, chainidx,
3670                                              PACKET_remaining(&spkt) == 0)) {
3671                 OPENSSL_free(rawexts);
3672                 goto err;
3673             }
3674             OPENSSL_free(rawexts);
3675         }
3676 
3677         if (!sk_X509_push(sk, x)) {
3678             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3679                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3680                      ERR_R_MALLOC_FAILURE);
3681             goto err;
3682         }
3683         x = NULL;
3684     }
3685 
3686     if (sk_X509_num(sk) <= 0) {
3687         /* TLS does not mind 0 certs returned */
3688         if (s->version == SSL3_VERSION) {
3689             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
3690                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3691                      SSL_R_NO_CERTIFICATES_RETURNED);
3692             goto err;
3693         }
3694         /* Fail for TLS only if we required a certificate */
3695         else if ((s->verify_mode & SSL_VERIFY_PEER) &&
3696                  (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
3697             SSLfatal(s, SSL_AD_CERTIFICATE_REQUIRED,
3698                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3699                      SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
3700             goto err;
3701         }
3702         /* No client certificate so digest cached records */
3703         if (s->s3->handshake_buffer && !ssl3_digest_cached_records(s, 0)) {
3704             /* SSLfatal() already called */
3705             goto err;
3706         }
3707     } else {
3708         EVP_PKEY *pkey;
3709         i = ssl_verify_cert_chain(s, sk);
3710         if (i <= 0) {
3711             SSLfatal(s, ssl_x509err2alert(s->verify_result),
3712                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3713                      SSL_R_CERTIFICATE_VERIFY_FAILED);
3714             goto err;
3715         }
3716         if (i > 1) {
3717             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
3718                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE, i);
3719             goto err;
3720         }
3721         pkey = X509_get0_pubkey(sk_X509_value(sk, 0));
3722         if (pkey == NULL) {
3723             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
3724                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3725                      SSL_R_UNKNOWN_CERTIFICATE_TYPE);
3726             goto err;
3727         }
3728     }
3729 
3730     /*
3731      * Sessions must be immutable once they go into the session cache. Otherwise
3732      * we can get multi-thread problems. Therefore we don't "update" sessions,
3733      * we replace them with a duplicate. Here, we need to do this every time
3734      * a new certificate is received via post-handshake authentication, as the
3735      * session may have already gone into the session cache.
3736      */
3737 
3738     if (s->post_handshake_auth == SSL_PHA_REQUESTED) {
3739         if ((new_sess = ssl_session_dup(s->session, 0)) == 0) {
3740             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3741                      SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE,
3742                      ERR_R_MALLOC_FAILURE);
3743             goto err;
3744         }
3745 
3746         SSL_SESSION_free(s->session);
3747         s->session = new_sess;
3748     }
3749 
3750     X509_free(s->session->peer);
3751     s->session->peer = sk_X509_shift(sk);
3752     s->session->verify_result = s->verify_result;
3753 
3754     sk_X509_pop_free(s->session->peer_chain, X509_free);
3755     s->session->peer_chain = sk;
3756     sk = NULL;
3757 
3758     /*
3759      * Freeze the handshake buffer. For <TLS1.3 we do this after the CKE
3760      * message
3761      */
3762     if (SSL_IS_TLS13(s) && !ssl3_digest_cached_records(s, 1)) {
3763         /* SSLfatal() already called */
3764         goto err;
3765     }
3766 
3767     /*
3768      * Inconsistency alert: cert_chain does *not* include the peer's own
3769      * certificate, while we do include it in statem_clnt.c
3770      */
3771 
3772     /* Save the current hash state for when we receive the CertificateVerify */
3773     if (SSL_IS_TLS13(s)) {
3774         if (!ssl_handshake_hash(s, s->cert_verify_hash,
3775                                 sizeof(s->cert_verify_hash),
3776                                 &s->cert_verify_hash_len)) {
3777             /* SSLfatal() already called */
3778             goto err;
3779         }
3780 
3781         /* Resend session tickets */
3782         s->sent_tickets = 0;
3783     }
3784 
3785     ret = MSG_PROCESS_CONTINUE_READING;
3786 
3787  err:
3788     X509_free(x);
3789     sk_X509_pop_free(sk, X509_free);
3790     return ret;
3791 }
3792 
3793 int tls_construct_server_certificate(SSL *s, WPACKET *pkt)
3794 {
3795     CERT_PKEY *cpk = s->s3->tmp.cert;
3796 
3797     if (cpk == NULL) {
3798         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3799                  SSL_F_TLS_CONSTRUCT_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
3800         return 0;
3801     }
3802 
3803     /*
3804      * In TLSv1.3 the certificate chain is always preceded by a 0 length context
3805      * for the server Certificate message
3806      */
3807     if (SSL_IS_TLS13(s) && !WPACKET_put_bytes_u8(pkt, 0)) {
3808         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3809                  SSL_F_TLS_CONSTRUCT_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
3810         return 0;
3811     }
3812     if (!ssl3_output_cert_chain(s, pkt, cpk)) {
3813         /* SSLfatal() already called */
3814         return 0;
3815     }
3816 
3817     return 1;
3818 }
3819 
3820 static int create_ticket_prequel(SSL *s, WPACKET *pkt, uint32_t age_add,
3821                                  unsigned char *tick_nonce)
3822 {
3823     /*
3824      * Ticket lifetime hint: For TLSv1.2 this is advisory only and we leave this
3825      * unspecified for resumed session (for simplicity).
3826      * In TLSv1.3 we reset the "time" field above, and always specify the
3827      * timeout.
3828      */
3829     if (!WPACKET_put_bytes_u32(pkt,
3830                                (s->hit && !SSL_IS_TLS13(s))
3831                                ? 0 : s->session->timeout)) {
3832         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CREATE_TICKET_PREQUEL,
3833                  ERR_R_INTERNAL_ERROR);
3834         return 0;
3835     }
3836 
3837     if (SSL_IS_TLS13(s)) {
3838         if (!WPACKET_put_bytes_u32(pkt, age_add)
3839                 || !WPACKET_sub_memcpy_u8(pkt, tick_nonce, TICKET_NONCE_SIZE)) {
3840             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CREATE_TICKET_PREQUEL,
3841                      ERR_R_INTERNAL_ERROR);
3842             return 0;
3843         }
3844     }
3845 
3846     /* Start the sub-packet for the actual ticket data */
3847     if (!WPACKET_start_sub_packet_u16(pkt)) {
3848         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CREATE_TICKET_PREQUEL,
3849                  ERR_R_INTERNAL_ERROR);
3850         return 0;
3851     }
3852 
3853     return 1;
3854 }
3855 
3856 static int construct_stateless_ticket(SSL *s, WPACKET *pkt, uint32_t age_add,
3857                                       unsigned char *tick_nonce)
3858 {
3859     unsigned char *senc = NULL;
3860     EVP_CIPHER_CTX *ctx = NULL;
3861     HMAC_CTX *hctx = NULL;
3862     unsigned char *p, *encdata1, *encdata2, *macdata1, *macdata2;
3863     const unsigned char *const_p;
3864     int len, slen_full, slen, lenfinal;
3865     SSL_SESSION *sess;
3866     unsigned int hlen;
3867     SSL_CTX *tctx = s->session_ctx;
3868     unsigned char iv[EVP_MAX_IV_LENGTH];
3869     unsigned char key_name[TLSEXT_KEYNAME_LENGTH];
3870     int iv_len, ok = 0;
3871     size_t macoffset, macendoffset;
3872 
3873     /* get session encoding length */
3874     slen_full = i2d_SSL_SESSION(s->session, NULL);
3875     /*
3876      * Some length values are 16 bits, so forget it if session is too
3877      * long
3878      */
3879     if (slen_full == 0 || slen_full > 0xFF00) {
3880         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3881                  ERR_R_INTERNAL_ERROR);
3882         goto err;
3883     }
3884     senc = OPENSSL_malloc(slen_full);
3885     if (senc == NULL) {
3886         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3887                  SSL_F_CONSTRUCT_STATELESS_TICKET, ERR_R_MALLOC_FAILURE);
3888         goto err;
3889     }
3890 
3891     ctx = EVP_CIPHER_CTX_new();
3892     hctx = HMAC_CTX_new();
3893     if (ctx == NULL || hctx == NULL) {
3894         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3895                  ERR_R_MALLOC_FAILURE);
3896         goto err;
3897     }
3898 
3899     p = senc;
3900     if (!i2d_SSL_SESSION(s->session, &p)) {
3901         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3902                  ERR_R_INTERNAL_ERROR);
3903         goto err;
3904     }
3905 
3906     /*
3907      * create a fresh copy (not shared with other threads) to clean up
3908      */
3909     const_p = senc;
3910     sess = d2i_SSL_SESSION(NULL, &const_p, slen_full);
3911     if (sess == NULL) {
3912         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3913                  ERR_R_INTERNAL_ERROR);
3914         goto err;
3915     }
3916 
3917     slen = i2d_SSL_SESSION(sess, NULL);
3918     if (slen == 0 || slen > slen_full) {
3919         /* shouldn't ever happen */
3920         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3921                  ERR_R_INTERNAL_ERROR);
3922         SSL_SESSION_free(sess);
3923         goto err;
3924     }
3925     p = senc;
3926     if (!i2d_SSL_SESSION(sess, &p)) {
3927         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3928                  ERR_R_INTERNAL_ERROR);
3929         SSL_SESSION_free(sess);
3930         goto err;
3931     }
3932     SSL_SESSION_free(sess);
3933 
3934     /*
3935      * Initialize HMAC and cipher contexts. If callback present it does
3936      * all the work otherwise use generated values from parent ctx.
3937      */
3938     if (tctx->ext.ticket_key_cb) {
3939         /* if 0 is returned, write an empty ticket */
3940         int ret = tctx->ext.ticket_key_cb(s, key_name, iv, ctx,
3941                                              hctx, 1);
3942 
3943         if (ret == 0) {
3944 
3945             /* Put timeout and length */
3946             if (!WPACKET_put_bytes_u32(pkt, 0)
3947                     || !WPACKET_put_bytes_u16(pkt, 0)) {
3948                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
3949                          SSL_F_CONSTRUCT_STATELESS_TICKET,
3950                          ERR_R_INTERNAL_ERROR);
3951                 goto err;
3952             }
3953             OPENSSL_free(senc);
3954             EVP_CIPHER_CTX_free(ctx);
3955             HMAC_CTX_free(hctx);
3956             return 1;
3957         }
3958         if (ret < 0) {
3959             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3960                      SSL_R_CALLBACK_FAILED);
3961             goto err;
3962         }
3963         iv_len = EVP_CIPHER_CTX_iv_length(ctx);
3964     } else {
3965         const EVP_CIPHER *cipher = EVP_aes_256_cbc();
3966 
3967         iv_len = EVP_CIPHER_iv_length(cipher);
3968         if (RAND_bytes(iv, iv_len) <= 0
3969                 || !EVP_EncryptInit_ex(ctx, cipher, NULL,
3970                                        tctx->ext.secure->tick_aes_key, iv)
3971                 || !HMAC_Init_ex(hctx, tctx->ext.secure->tick_hmac_key,
3972                                  sizeof(tctx->ext.secure->tick_hmac_key),
3973                                  EVP_sha256(), NULL)) {
3974             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
3975                      ERR_R_INTERNAL_ERROR);
3976             goto err;
3977         }
3978         memcpy(key_name, tctx->ext.tick_key_name,
3979                sizeof(tctx->ext.tick_key_name));
3980     }
3981 
3982     if (!create_ticket_prequel(s, pkt, age_add, tick_nonce)) {
3983         /* SSLfatal() already called */
3984         goto err;
3985     }
3986 
3987     if (!WPACKET_get_total_written(pkt, &macoffset)
3988                /* Output key name */
3989             || !WPACKET_memcpy(pkt, key_name, sizeof(key_name))
3990                /* output IV */
3991             || !WPACKET_memcpy(pkt, iv, iv_len)
3992             || !WPACKET_reserve_bytes(pkt, slen + EVP_MAX_BLOCK_LENGTH,
3993                                       &encdata1)
3994                /* Encrypt session data */
3995             || !EVP_EncryptUpdate(ctx, encdata1, &len, senc, slen)
3996             || !WPACKET_allocate_bytes(pkt, len, &encdata2)
3997             || encdata1 != encdata2
3998             || !EVP_EncryptFinal(ctx, encdata1 + len, &lenfinal)
3999             || !WPACKET_allocate_bytes(pkt, lenfinal, &encdata2)
4000             || encdata1 + len != encdata2
4001             || len + lenfinal > slen + EVP_MAX_BLOCK_LENGTH
4002             || !WPACKET_get_total_written(pkt, &macendoffset)
4003             || !HMAC_Update(hctx,
4004                             (unsigned char *)s->init_buf->data + macoffset,
4005                             macendoffset - macoffset)
4006             || !WPACKET_reserve_bytes(pkt, EVP_MAX_MD_SIZE, &macdata1)
4007             || !HMAC_Final(hctx, macdata1, &hlen)
4008             || hlen > EVP_MAX_MD_SIZE
4009             || !WPACKET_allocate_bytes(pkt, hlen, &macdata2)
4010             || macdata1 != macdata2) {
4011         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4012                  SSL_F_CONSTRUCT_STATELESS_TICKET, ERR_R_INTERNAL_ERROR);
4013         goto err;
4014     }
4015 
4016     /* Close the sub-packet created by create_ticket_prequel() */
4017     if (!WPACKET_close(pkt)) {
4018         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATELESS_TICKET,
4019                  ERR_R_INTERNAL_ERROR);
4020         goto err;
4021     }
4022 
4023     ok = 1;
4024  err:
4025     OPENSSL_free(senc);
4026     EVP_CIPHER_CTX_free(ctx);
4027     HMAC_CTX_free(hctx);
4028     return ok;
4029 }
4030 
4031 static int construct_stateful_ticket(SSL *s, WPACKET *pkt, uint32_t age_add,
4032                                      unsigned char *tick_nonce)
4033 {
4034     if (!create_ticket_prequel(s, pkt, age_add, tick_nonce)) {
4035         /* SSLfatal() already called */
4036         return 0;
4037     }
4038 
4039     if (!WPACKET_memcpy(pkt, s->session->session_id,
4040                         s->session->session_id_length)
4041             || !WPACKET_close(pkt)) {
4042         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_STATEFUL_TICKET,
4043                  ERR_R_INTERNAL_ERROR);
4044         return 0;
4045     }
4046 
4047     return 1;
4048 }
4049 
4050 int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt)
4051 {
4052     SSL_CTX *tctx = s->session_ctx;
4053     unsigned char tick_nonce[TICKET_NONCE_SIZE];
4054     union {
4055         unsigned char age_add_c[sizeof(uint32_t)];
4056         uint32_t age_add;
4057     } age_add_u;
4058 
4059     age_add_u.age_add = 0;
4060 
4061     if (SSL_IS_TLS13(s)) {
4062         size_t i, hashlen;
4063         uint64_t nonce;
4064         static const unsigned char nonce_label[] = "resumption";
4065         const EVP_MD *md = ssl_handshake_md(s);
4066         int hashleni = EVP_MD_size(md);
4067 
4068         /* Ensure cast to size_t is safe */
4069         if (!ossl_assert(hashleni >= 0)) {
4070             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4071                      SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4072                      ERR_R_INTERNAL_ERROR);
4073             goto err;
4074         }
4075         hashlen = (size_t)hashleni;
4076 
4077         /*
4078          * If we already sent one NewSessionTicket, or we resumed then
4079          * s->session may already be in a cache and so we must not modify it.
4080          * Instead we need to take a copy of it and modify that.
4081          */
4082         if (s->sent_tickets != 0 || s->hit) {
4083             SSL_SESSION *new_sess = ssl_session_dup(s->session, 0);
4084 
4085             if (new_sess == NULL) {
4086                 /* SSLfatal already called */
4087                 goto err;
4088             }
4089 
4090             SSL_SESSION_free(s->session);
4091             s->session = new_sess;
4092         }
4093 
4094         if (!ssl_generate_session_id(s, s->session)) {
4095             /* SSLfatal() already called */
4096             goto err;
4097         }
4098         if (RAND_bytes(age_add_u.age_add_c, sizeof(age_add_u)) <= 0) {
4099             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4100                      SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4101                      ERR_R_INTERNAL_ERROR);
4102             goto err;
4103         }
4104         s->session->ext.tick_age_add = age_add_u.age_add;
4105 
4106         nonce = s->next_ticket_nonce;
4107         for (i = TICKET_NONCE_SIZE; i > 0; i--) {
4108             tick_nonce[i - 1] = (unsigned char)(nonce & 0xff);
4109             nonce >>= 8;
4110         }
4111 
4112         if (!tls13_hkdf_expand(s, md, s->resumption_master_secret,
4113                                nonce_label,
4114                                sizeof(nonce_label) - 1,
4115                                tick_nonce,
4116                                TICKET_NONCE_SIZE,
4117                                s->session->master_key,
4118                                hashlen, 1)) {
4119             /* SSLfatal() already called */
4120             goto err;
4121         }
4122         s->session->master_key_length = hashlen;
4123 
4124         s->session->time = (long)time(NULL);
4125         if (s->s3->alpn_selected != NULL) {
4126             OPENSSL_free(s->session->ext.alpn_selected);
4127             s->session->ext.alpn_selected =
4128                 OPENSSL_memdup(s->s3->alpn_selected, s->s3->alpn_selected_len);
4129             if (s->session->ext.alpn_selected == NULL) {
4130                 s->session->ext.alpn_selected_len = 0;
4131                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4132                          SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4133                          ERR_R_MALLOC_FAILURE);
4134                 goto err;
4135             }
4136             s->session->ext.alpn_selected_len = s->s3->alpn_selected_len;
4137         }
4138         s->session->ext.max_early_data = s->max_early_data;
4139     }
4140 
4141     if (tctx->generate_ticket_cb != NULL &&
4142         tctx->generate_ticket_cb(s, tctx->ticket_cb_data) == 0) {
4143         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
4144                  SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
4145                  ERR_R_INTERNAL_ERROR);
4146         goto err;
4147     }
4148     /*
4149      * If we are using anti-replay protection then we behave as if
4150      * SSL_OP_NO_TICKET is set - we are caching tickets anyway so there
4151      * is no point in using full stateless tickets.
4152      */
4153     if (SSL_IS_TLS13(s)
4154             && ((s->options & SSL_OP_NO_TICKET) != 0
4155                 || (s->max_early_data > 0
4156                     && (s->options & SSL_OP_NO_ANTI_REPLAY) == 0))) {
4157         if (!construct_stateful_ticket(s, pkt, age_add_u.age_add, tick_nonce)) {
4158             /* SSLfatal() already called */
4159             goto err;
4160         }
4161     } else if (!construct_stateless_ticket(s, pkt, age_add_u.age_add,
4162                                            tick_nonce)) {
4163         /* SSLfatal() already called */
4164         goto err;
4165     }
4166 
4167     if (SSL_IS_TLS13(s)) {
4168         if (!tls_construct_extensions(s, pkt,
4169                                       SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
4170                                       NULL, 0)) {
4171             /* SSLfatal() already called */
4172             goto err;
4173         }
4174         /*
4175          * Increment both |sent_tickets| and |next_ticket_nonce|. |sent_tickets|
4176          * gets reset to 0 if we send more tickets following a post-handshake
4177          * auth, but |next_ticket_nonce| does not.
4178          */
4179         s->sent_tickets++;
4180         s->next_ticket_nonce++;
4181         ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
4182     }
4183 
4184     return 1;
4185  err:
4186     return 0;
4187 }
4188 
4189 /*
4190  * In TLSv1.3 this is called from the extensions code, otherwise it is used to
4191  * create a separate message. Returns 1 on success or 0 on failure.
4192  */
4193 int tls_construct_cert_status_body(SSL *s, WPACKET *pkt)
4194 {
4195     if (!WPACKET_put_bytes_u8(pkt, s->ext.status_type)
4196             || !WPACKET_sub_memcpy_u24(pkt, s->ext.ocsp.resp,
4197                                        s->ext.ocsp.resp_len)) {
4198         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CERT_STATUS_BODY,
4199                  ERR_R_INTERNAL_ERROR);
4200         return 0;
4201     }
4202 
4203     return 1;
4204 }
4205 
4206 int tls_construct_cert_status(SSL *s, WPACKET *pkt)
4207 {
4208     if (!tls_construct_cert_status_body(s, pkt)) {
4209         /* SSLfatal() already called */
4210         return 0;
4211     }
4212 
4213     return 1;
4214 }
4215 
4216 #ifndef OPENSSL_NO_NEXTPROTONEG
4217 /*
4218  * tls_process_next_proto reads a Next Protocol Negotiation handshake message.
4219  * It sets the next_proto member in s if found
4220  */
4221 MSG_PROCESS_RETURN tls_process_next_proto(SSL *s, PACKET *pkt)
4222 {
4223     PACKET next_proto, padding;
4224     size_t next_proto_len;
4225 
4226     /*-
4227      * The payload looks like:
4228      *   uint8 proto_len;
4229      *   uint8 proto[proto_len];
4230      *   uint8 padding_len;
4231      *   uint8 padding[padding_len];
4232      */
4233     if (!PACKET_get_length_prefixed_1(pkt, &next_proto)
4234         || !PACKET_get_length_prefixed_1(pkt, &padding)
4235         || PACKET_remaining(pkt) > 0) {
4236         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_NEXT_PROTO,
4237                  SSL_R_LENGTH_MISMATCH);
4238         return MSG_PROCESS_ERROR;
4239     }
4240 
4241     if (!PACKET_memdup(&next_proto, &s->ext.npn, &next_proto_len)) {
4242         s->ext.npn_len = 0;
4243         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_NEXT_PROTO,
4244                  ERR_R_INTERNAL_ERROR);
4245         return MSG_PROCESS_ERROR;
4246     }
4247 
4248     s->ext.npn_len = (unsigned char)next_proto_len;
4249 
4250     return MSG_PROCESS_CONTINUE_READING;
4251 }
4252 #endif
4253 
4254 static int tls_construct_encrypted_extensions(SSL *s, WPACKET *pkt)
4255 {
4256     if (!tls_construct_extensions(s, pkt, SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
4257                                   NULL, 0)) {
4258         /* SSLfatal() already called */
4259         return 0;
4260     }
4261 
4262     return 1;
4263 }
4264 
4265 MSG_PROCESS_RETURN tls_process_end_of_early_data(SSL *s, PACKET *pkt)
4266 {
4267     if (PACKET_remaining(pkt) != 0) {
4268         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_END_OF_EARLY_DATA,
4269                  SSL_R_LENGTH_MISMATCH);
4270         return MSG_PROCESS_ERROR;
4271     }
4272 
4273     if (s->early_data_state != SSL_EARLY_DATA_READING
4274             && s->early_data_state != SSL_EARLY_DATA_READ_RETRY) {
4275         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_END_OF_EARLY_DATA,
4276                  ERR_R_INTERNAL_ERROR);
4277         return MSG_PROCESS_ERROR;
4278     }
4279 
4280     /*
4281      * EndOfEarlyData signals a key change so the end of the message must be on
4282      * a record boundary.
4283      */
4284     if (RECORD_LAYER_processed_read_pending(&s->rlayer)) {
4285         SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
4286                  SSL_F_TLS_PROCESS_END_OF_EARLY_DATA,
4287                  SSL_R_NOT_ON_RECORD_BOUNDARY);
4288         return MSG_PROCESS_ERROR;
4289     }
4290 
4291     s->early_data_state = SSL_EARLY_DATA_FINISHED_READING;
4292     if (!s->method->ssl3_enc->change_cipher_state(s,
4293                 SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_SERVER_READ)) {
4294         /* SSLfatal() already called */
4295         return MSG_PROCESS_ERROR;
4296     }
4297 
4298     return MSG_PROCESS_CONTINUE_READING;
4299 }
4300