xref: /freebsd/crypto/openssl/ssl/statem/extensions_clnt.c (revision 38effe887ee979f91ad5abf42a2291558e7ff8d1)
1 /*
2  * Copyright 2016-2019 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 #include <openssl/ocsp.h>
11 #include "../ssl_locl.h"
12 #include "internal/cryptlib.h"
13 #include "statem_locl.h"
14 
15 EXT_RETURN tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt,
16                                           unsigned int context, X509 *x,
17                                           size_t chainidx)
18 {
19     /* Add RI if renegotiating */
20     if (!s->renegotiate)
21         return EXT_RETURN_NOT_SENT;
22 
23     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
24             || !WPACKET_start_sub_packet_u16(pkt)
25             || !WPACKET_sub_memcpy_u8(pkt, s->s3->previous_client_finished,
26                                s->s3->previous_client_finished_len)
27             || !WPACKET_close(pkt)) {
28         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_RENEGOTIATE,
29                  ERR_R_INTERNAL_ERROR);
30         return EXT_RETURN_FAIL;
31     }
32 
33     return EXT_RETURN_SENT;
34 }
35 
36 EXT_RETURN tls_construct_ctos_server_name(SSL *s, WPACKET *pkt,
37                                           unsigned int context, X509 *x,
38                                           size_t chainidx)
39 {
40     if (s->ext.hostname == NULL)
41         return EXT_RETURN_NOT_SENT;
42 
43     /* Add TLS extension servername to the Client Hello message */
44     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_server_name)
45                /* Sub-packet for server_name extension */
46             || !WPACKET_start_sub_packet_u16(pkt)
47                /* Sub-packet for servername list (always 1 hostname)*/
48             || !WPACKET_start_sub_packet_u16(pkt)
49             || !WPACKET_put_bytes_u8(pkt, TLSEXT_NAMETYPE_host_name)
50             || !WPACKET_sub_memcpy_u16(pkt, s->ext.hostname,
51                                        strlen(s->ext.hostname))
52             || !WPACKET_close(pkt)
53             || !WPACKET_close(pkt)) {
54         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_SERVER_NAME,
55                  ERR_R_INTERNAL_ERROR);
56         return EXT_RETURN_FAIL;
57     }
58 
59     return EXT_RETURN_SENT;
60 }
61 
62 /* Push a Max Fragment Len extension into ClientHello */
63 EXT_RETURN tls_construct_ctos_maxfragmentlen(SSL *s, WPACKET *pkt,
64                                              unsigned int context, X509 *x,
65                                              size_t chainidx)
66 {
67     if (s->ext.max_fragment_len_mode == TLSEXT_max_fragment_length_DISABLED)
68         return EXT_RETURN_NOT_SENT;
69 
70     /* Add Max Fragment Length extension if client enabled it. */
71     /*-
72      * 4 bytes for this extension type and extension length
73      * 1 byte for the Max Fragment Length code value.
74      */
75     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_max_fragment_length)
76             /* Sub-packet for Max Fragment Length extension (1 byte) */
77             || !WPACKET_start_sub_packet_u16(pkt)
78             || !WPACKET_put_bytes_u8(pkt, s->ext.max_fragment_len_mode)
79             || !WPACKET_close(pkt)) {
80         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
81                  SSL_F_TLS_CONSTRUCT_CTOS_MAXFRAGMENTLEN, ERR_R_INTERNAL_ERROR);
82         return EXT_RETURN_FAIL;
83     }
84 
85     return EXT_RETURN_SENT;
86 }
87 
88 #ifndef OPENSSL_NO_SRP
89 EXT_RETURN tls_construct_ctos_srp(SSL *s, WPACKET *pkt, unsigned int context,
90                                   X509 *x, size_t chainidx)
91 {
92     /* Add SRP username if there is one */
93     if (s->srp_ctx.login == NULL)
94         return EXT_RETURN_NOT_SENT;
95 
96     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_srp)
97                /* Sub-packet for SRP extension */
98             || !WPACKET_start_sub_packet_u16(pkt)
99             || !WPACKET_start_sub_packet_u8(pkt)
100                /* login must not be zero...internal error if so */
101             || !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)
102             || !WPACKET_memcpy(pkt, s->srp_ctx.login,
103                                strlen(s->srp_ctx.login))
104             || !WPACKET_close(pkt)
105             || !WPACKET_close(pkt)) {
106         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_SRP,
107                  ERR_R_INTERNAL_ERROR);
108         return EXT_RETURN_FAIL;
109     }
110 
111     return EXT_RETURN_SENT;
112 }
113 #endif
114 
115 #ifndef OPENSSL_NO_EC
116 static int use_ecc(SSL *s)
117 {
118     int i, end, ret = 0;
119     unsigned long alg_k, alg_a;
120     STACK_OF(SSL_CIPHER) *cipher_stack = NULL;
121 
122     /* See if we support any ECC ciphersuites */
123     if (s->version == SSL3_VERSION)
124         return 0;
125 
126     cipher_stack = SSL_get1_supported_ciphers(s);
127     end = sk_SSL_CIPHER_num(cipher_stack);
128     for (i = 0; i < end; i++) {
129         const SSL_CIPHER *c = sk_SSL_CIPHER_value(cipher_stack, i);
130 
131         alg_k = c->algorithm_mkey;
132         alg_a = c->algorithm_auth;
133         if ((alg_k & (SSL_kECDHE | SSL_kECDHEPSK))
134                 || (alg_a & SSL_aECDSA)
135                 || c->min_tls >= TLS1_3_VERSION) {
136             ret = 1;
137             break;
138         }
139     }
140 
141     sk_SSL_CIPHER_free(cipher_stack);
142     return ret;
143 }
144 
145 EXT_RETURN tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt,
146                                             unsigned int context, X509 *x,
147                                             size_t chainidx)
148 {
149     const unsigned char *pformats;
150     size_t num_formats;
151 
152     if (!use_ecc(s))
153         return EXT_RETURN_NOT_SENT;
154 
155     /* Add TLS extension ECPointFormats to the ClientHello message */
156     tls1_get_formatlist(s, &pformats, &num_formats);
157 
158     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_ec_point_formats)
159                /* Sub-packet for formats extension */
160             || !WPACKET_start_sub_packet_u16(pkt)
161             || !WPACKET_sub_memcpy_u8(pkt, pformats, num_formats)
162             || !WPACKET_close(pkt)) {
163         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
164                  SSL_F_TLS_CONSTRUCT_CTOS_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
165         return EXT_RETURN_FAIL;
166     }
167 
168     return EXT_RETURN_SENT;
169 }
170 
171 EXT_RETURN tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
172                                                unsigned int context, X509 *x,
173                                                size_t chainidx)
174 {
175     const uint16_t *pgroups = NULL;
176     size_t num_groups = 0, i;
177 
178     if (!use_ecc(s))
179         return EXT_RETURN_NOT_SENT;
180 
181     /*
182      * Add TLS extension supported_groups to the ClientHello message
183      */
184     /* TODO(TLS1.3): Add support for DHE groups */
185     tls1_get_supported_groups(s, &pgroups, &num_groups);
186 
187     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_groups)
188                /* Sub-packet for supported_groups extension */
189             || !WPACKET_start_sub_packet_u16(pkt)
190             || !WPACKET_start_sub_packet_u16(pkt)) {
191         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
192                  SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
193                  ERR_R_INTERNAL_ERROR);
194         return EXT_RETURN_FAIL;
195     }
196     /* Copy curve ID if supported */
197     for (i = 0; i < num_groups; i++) {
198         uint16_t ctmp = pgroups[i];
199 
200         if (tls_curve_allowed(s, ctmp, SSL_SECOP_CURVE_SUPPORTED)) {
201             if (!WPACKET_put_bytes_u16(pkt, ctmp)) {
202                     SSLfatal(s, SSL_AD_INTERNAL_ERROR,
203                              SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
204                              ERR_R_INTERNAL_ERROR);
205                     return EXT_RETURN_FAIL;
206                 }
207         }
208     }
209     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
210         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
211                  SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
212                  ERR_R_INTERNAL_ERROR);
213         return EXT_RETURN_FAIL;
214     }
215 
216     return EXT_RETURN_SENT;
217 }
218 #endif
219 
220 EXT_RETURN tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt,
221                                              unsigned int context, X509 *x,
222                                              size_t chainidx)
223 {
224     size_t ticklen;
225 
226     if (!tls_use_ticket(s))
227         return EXT_RETURN_NOT_SENT;
228 
229     if (!s->new_session && s->session != NULL
230             && s->session->ext.tick != NULL
231             && s->session->ssl_version != TLS1_3_VERSION) {
232         ticklen = s->session->ext.ticklen;
233     } else if (s->session && s->ext.session_ticket != NULL
234                && s->ext.session_ticket->data != NULL) {
235         ticklen = s->ext.session_ticket->length;
236         s->session->ext.tick = OPENSSL_malloc(ticklen);
237         if (s->session->ext.tick == NULL) {
238             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
239                      SSL_F_TLS_CONSTRUCT_CTOS_SESSION_TICKET,
240                      ERR_R_INTERNAL_ERROR);
241             return EXT_RETURN_FAIL;
242         }
243         memcpy(s->session->ext.tick,
244                s->ext.session_ticket->data, ticklen);
245         s->session->ext.ticklen = ticklen;
246     } else {
247         ticklen = 0;
248     }
249 
250     if (ticklen == 0 && s->ext.session_ticket != NULL &&
251             s->ext.session_ticket->data == NULL)
252         return EXT_RETURN_NOT_SENT;
253 
254     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_session_ticket)
255             || !WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick, ticklen)) {
256         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
257                  SSL_F_TLS_CONSTRUCT_CTOS_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
258         return EXT_RETURN_FAIL;
259     }
260 
261     return EXT_RETURN_SENT;
262 }
263 
264 EXT_RETURN tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt,
265                                        unsigned int context, X509 *x,
266                                        size_t chainidx)
267 {
268     size_t salglen;
269     const uint16_t *salg;
270 
271     if (!SSL_CLIENT_USE_SIGALGS(s))
272         return EXT_RETURN_NOT_SENT;
273 
274     salglen = tls12_get_psigalgs(s, 1, &salg);
275     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_signature_algorithms)
276                /* Sub-packet for sig-algs extension */
277             || !WPACKET_start_sub_packet_u16(pkt)
278                /* Sub-packet for the actual list */
279             || !WPACKET_start_sub_packet_u16(pkt)
280             || !tls12_copy_sigalgs(s, pkt, salg, salglen)
281             || !WPACKET_close(pkt)
282             || !WPACKET_close(pkt)) {
283         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_SIG_ALGS,
284                  ERR_R_INTERNAL_ERROR);
285         return EXT_RETURN_FAIL;
286     }
287 
288     return EXT_RETURN_SENT;
289 }
290 
291 #ifndef OPENSSL_NO_OCSP
292 EXT_RETURN tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
293                                              unsigned int context, X509 *x,
294                                              size_t chainidx)
295 {
296     int i;
297 
298     /* This extension isn't defined for client Certificates */
299     if (x != NULL)
300         return EXT_RETURN_NOT_SENT;
301 
302     if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp)
303         return EXT_RETURN_NOT_SENT;
304 
305     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
306                /* Sub-packet for status request extension */
307             || !WPACKET_start_sub_packet_u16(pkt)
308             || !WPACKET_put_bytes_u8(pkt, TLSEXT_STATUSTYPE_ocsp)
309                /* Sub-packet for the ids */
310             || !WPACKET_start_sub_packet_u16(pkt)) {
311         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
312                  SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
313         return EXT_RETURN_FAIL;
314     }
315     for (i = 0; i < sk_OCSP_RESPID_num(s->ext.ocsp.ids); i++) {
316         unsigned char *idbytes;
317         OCSP_RESPID *id = sk_OCSP_RESPID_value(s->ext.ocsp.ids, i);
318         int idlen = i2d_OCSP_RESPID(id, NULL);
319 
320         if (idlen <= 0
321                    /* Sub-packet for an individual id */
322                 || !WPACKET_sub_allocate_bytes_u16(pkt, idlen, &idbytes)
323                 || i2d_OCSP_RESPID(id, &idbytes) != idlen) {
324             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
325                      SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST,
326                      ERR_R_INTERNAL_ERROR);
327             return EXT_RETURN_FAIL;
328         }
329     }
330     if (!WPACKET_close(pkt)
331             || !WPACKET_start_sub_packet_u16(pkt)) {
332         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
333                  SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
334         return EXT_RETURN_FAIL;
335     }
336     if (s->ext.ocsp.exts) {
337         unsigned char *extbytes;
338         int extlen = i2d_X509_EXTENSIONS(s->ext.ocsp.exts, NULL);
339 
340         if (extlen < 0) {
341             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
342                      SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST,
343                      ERR_R_INTERNAL_ERROR);
344             return EXT_RETURN_FAIL;
345         }
346         if (!WPACKET_allocate_bytes(pkt, extlen, &extbytes)
347                 || i2d_X509_EXTENSIONS(s->ext.ocsp.exts, &extbytes)
348                    != extlen) {
349             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
350                      SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST,
351                      ERR_R_INTERNAL_ERROR);
352             return EXT_RETURN_FAIL;
353        }
354     }
355     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
356         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
357                  SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
358         return EXT_RETURN_FAIL;
359     }
360 
361     return EXT_RETURN_SENT;
362 }
363 #endif
364 
365 #ifndef OPENSSL_NO_NEXTPROTONEG
366 EXT_RETURN tls_construct_ctos_npn(SSL *s, WPACKET *pkt, unsigned int context,
367                                   X509 *x, size_t chainidx)
368 {
369     if (s->ctx->ext.npn_select_cb == NULL || !SSL_IS_FIRST_HANDSHAKE(s))
370         return EXT_RETURN_NOT_SENT;
371 
372     /*
373      * The client advertises an empty extension to indicate its support
374      * for Next Protocol Negotiation
375      */
376     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_next_proto_neg)
377             || !WPACKET_put_bytes_u16(pkt, 0)) {
378         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_NPN,
379                  ERR_R_INTERNAL_ERROR);
380         return EXT_RETURN_FAIL;
381     }
382 
383     return EXT_RETURN_SENT;
384 }
385 #endif
386 
387 EXT_RETURN tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, unsigned int context,
388                                    X509 *x, size_t chainidx)
389 {
390     s->s3->alpn_sent = 0;
391 
392     if (s->ext.alpn == NULL || !SSL_IS_FIRST_HANDSHAKE(s))
393         return EXT_RETURN_NOT_SENT;
394 
395     if (!WPACKET_put_bytes_u16(pkt,
396                 TLSEXT_TYPE_application_layer_protocol_negotiation)
397                /* Sub-packet ALPN extension */
398             || !WPACKET_start_sub_packet_u16(pkt)
399             || !WPACKET_sub_memcpy_u16(pkt, s->ext.alpn, s->ext.alpn_len)
400             || !WPACKET_close(pkt)) {
401         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_ALPN,
402                  ERR_R_INTERNAL_ERROR);
403         return EXT_RETURN_FAIL;
404     }
405     s->s3->alpn_sent = 1;
406 
407     return EXT_RETURN_SENT;
408 }
409 
410 
411 #ifndef OPENSSL_NO_SRTP
412 EXT_RETURN tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt,
413                                        unsigned int context, X509 *x,
414                                        size_t chainidx)
415 {
416     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = SSL_get_srtp_profiles(s);
417     int i, end;
418 
419     if (clnt == NULL)
420         return EXT_RETURN_NOT_SENT;
421 
422     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_use_srtp)
423                /* Sub-packet for SRTP extension */
424             || !WPACKET_start_sub_packet_u16(pkt)
425                /* Sub-packet for the protection profile list */
426             || !WPACKET_start_sub_packet_u16(pkt)) {
427         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_USE_SRTP,
428                  ERR_R_INTERNAL_ERROR);
429         return EXT_RETURN_FAIL;
430     }
431 
432     end = sk_SRTP_PROTECTION_PROFILE_num(clnt);
433     for (i = 0; i < end; i++) {
434         const SRTP_PROTECTION_PROFILE *prof =
435             sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
436 
437         if (prof == NULL || !WPACKET_put_bytes_u16(pkt, prof->id)) {
438             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
439                      SSL_F_TLS_CONSTRUCT_CTOS_USE_SRTP, ERR_R_INTERNAL_ERROR);
440             return EXT_RETURN_FAIL;
441         }
442     }
443     if (!WPACKET_close(pkt)
444                /* Add an empty use_mki value */
445             || !WPACKET_put_bytes_u8(pkt, 0)
446             || !WPACKET_close(pkt)) {
447         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_USE_SRTP,
448                  ERR_R_INTERNAL_ERROR);
449         return EXT_RETURN_FAIL;
450     }
451 
452     return EXT_RETURN_SENT;
453 }
454 #endif
455 
456 EXT_RETURN tls_construct_ctos_etm(SSL *s, WPACKET *pkt, unsigned int context,
457                                   X509 *x, size_t chainidx)
458 {
459     if (s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
460         return EXT_RETURN_NOT_SENT;
461 
462     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_encrypt_then_mac)
463             || !WPACKET_put_bytes_u16(pkt, 0)) {
464         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_ETM,
465                  ERR_R_INTERNAL_ERROR);
466         return EXT_RETURN_FAIL;
467     }
468 
469     return EXT_RETURN_SENT;
470 }
471 
472 #ifndef OPENSSL_NO_CT
473 EXT_RETURN tls_construct_ctos_sct(SSL *s, WPACKET *pkt, unsigned int context,
474                                   X509 *x, size_t chainidx)
475 {
476     if (s->ct_validation_callback == NULL)
477         return EXT_RETURN_NOT_SENT;
478 
479     /* Not defined for client Certificates */
480     if (x != NULL)
481         return EXT_RETURN_NOT_SENT;
482 
483     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_signed_certificate_timestamp)
484             || !WPACKET_put_bytes_u16(pkt, 0)) {
485         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_SCT,
486                  ERR_R_INTERNAL_ERROR);
487         return EXT_RETURN_FAIL;
488     }
489 
490     return EXT_RETURN_SENT;
491 }
492 #endif
493 
494 EXT_RETURN tls_construct_ctos_ems(SSL *s, WPACKET *pkt, unsigned int context,
495                                   X509 *x, size_t chainidx)
496 {
497     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
498             || !WPACKET_put_bytes_u16(pkt, 0)) {
499         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_EMS,
500                  ERR_R_INTERNAL_ERROR);
501         return EXT_RETURN_FAIL;
502     }
503 
504     return EXT_RETURN_SENT;
505 }
506 
507 EXT_RETURN tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
508                                                  unsigned int context, X509 *x,
509                                                  size_t chainidx)
510 {
511     int currv, min_version, max_version, reason;
512 
513     reason = ssl_get_min_max_version(s, &min_version, &max_version, NULL);
514     if (reason != 0) {
515         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
516                  SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS, reason);
517         return EXT_RETURN_FAIL;
518     }
519 
520     /*
521      * Don't include this if we can't negotiate TLSv1.3. We can do a straight
522      * comparison here because we will never be called in DTLS.
523      */
524     if (max_version < TLS1_3_VERSION)
525         return EXT_RETURN_NOT_SENT;
526 
527     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_versions)
528             || !WPACKET_start_sub_packet_u16(pkt)
529             || !WPACKET_start_sub_packet_u8(pkt)) {
530         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
531                  SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
532                  ERR_R_INTERNAL_ERROR);
533         return EXT_RETURN_FAIL;
534     }
535 
536     for (currv = max_version; currv >= min_version; currv--) {
537         if (!WPACKET_put_bytes_u16(pkt, currv)) {
538             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
539                      SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
540                      ERR_R_INTERNAL_ERROR);
541             return EXT_RETURN_FAIL;
542         }
543     }
544     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
545         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
546                  SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
547                  ERR_R_INTERNAL_ERROR);
548         return EXT_RETURN_FAIL;
549     }
550 
551     return EXT_RETURN_SENT;
552 }
553 
554 /*
555  * Construct a psk_kex_modes extension.
556  */
557 EXT_RETURN tls_construct_ctos_psk_kex_modes(SSL *s, WPACKET *pkt,
558                                             unsigned int context, X509 *x,
559                                             size_t chainidx)
560 {
561 #ifndef OPENSSL_NO_TLS1_3
562     int nodhe = s->options & SSL_OP_ALLOW_NO_DHE_KEX;
563 
564     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk_kex_modes)
565             || !WPACKET_start_sub_packet_u16(pkt)
566             || !WPACKET_start_sub_packet_u8(pkt)
567             || !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE_DHE)
568             || (nodhe && !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE))
569             || !WPACKET_close(pkt)
570             || !WPACKET_close(pkt)) {
571         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
572                  SSL_F_TLS_CONSTRUCT_CTOS_PSK_KEX_MODES, ERR_R_INTERNAL_ERROR);
573         return EXT_RETURN_FAIL;
574     }
575 
576     s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_KE_DHE;
577     if (nodhe)
578         s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE;
579 #endif
580 
581     return EXT_RETURN_SENT;
582 }
583 
584 #ifndef OPENSSL_NO_TLS1_3
585 static int add_key_share(SSL *s, WPACKET *pkt, unsigned int curve_id)
586 {
587     unsigned char *encoded_point = NULL;
588     EVP_PKEY *key_share_key = NULL;
589     size_t encodedlen;
590 
591     if (s->s3->tmp.pkey != NULL) {
592         if (!ossl_assert(s->hello_retry_request == SSL_HRR_PENDING)) {
593             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_ADD_KEY_SHARE,
594                      ERR_R_INTERNAL_ERROR);
595             return 0;
596         }
597         /*
598          * Could happen if we got an HRR that wasn't requesting a new key_share
599          */
600         key_share_key = s->s3->tmp.pkey;
601     } else {
602         key_share_key = ssl_generate_pkey_group(s, curve_id);
603         if (key_share_key == NULL) {
604             /* SSLfatal() already called */
605             return 0;
606         }
607     }
608 
609     /* Encode the public key. */
610     encodedlen = EVP_PKEY_get1_tls_encodedpoint(key_share_key,
611                                                 &encoded_point);
612     if (encodedlen == 0) {
613         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_ADD_KEY_SHARE, ERR_R_EC_LIB);
614         goto err;
615     }
616 
617     /* Create KeyShareEntry */
618     if (!WPACKET_put_bytes_u16(pkt, curve_id)
619             || !WPACKET_sub_memcpy_u16(pkt, encoded_point, encodedlen)) {
620         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_ADD_KEY_SHARE,
621                  ERR_R_INTERNAL_ERROR);
622         goto err;
623     }
624 
625     /*
626      * TODO(TLS1.3): When changing to send more than one key_share we're
627      * going to need to be able to save more than one EVP_PKEY. For now
628      * we reuse the existing tmp.pkey
629      */
630     s->s3->tmp.pkey = key_share_key;
631     s->s3->group_id = curve_id;
632     OPENSSL_free(encoded_point);
633 
634     return 1;
635  err:
636     if (s->s3->tmp.pkey == NULL)
637         EVP_PKEY_free(key_share_key);
638     OPENSSL_free(encoded_point);
639     return 0;
640 }
641 #endif
642 
643 EXT_RETURN tls_construct_ctos_key_share(SSL *s, WPACKET *pkt,
644                                         unsigned int context, X509 *x,
645                                         size_t chainidx)
646 {
647 #ifndef OPENSSL_NO_TLS1_3
648     size_t i, num_groups = 0;
649     const uint16_t *pgroups = NULL;
650     uint16_t curve_id = 0;
651 
652     /* key_share extension */
653     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
654                /* Extension data sub-packet */
655             || !WPACKET_start_sub_packet_u16(pkt)
656                /* KeyShare list sub-packet */
657             || !WPACKET_start_sub_packet_u16(pkt)) {
658         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE,
659                  ERR_R_INTERNAL_ERROR);
660         return EXT_RETURN_FAIL;
661     }
662 
663     tls1_get_supported_groups(s, &pgroups, &num_groups);
664 
665     /*
666      * TODO(TLS1.3): Make the number of key_shares sent configurable. For
667      * now, just send one
668      */
669     if (s->s3->group_id != 0) {
670         curve_id = s->s3->group_id;
671     } else {
672         for (i = 0; i < num_groups; i++) {
673 
674             if (!tls_curve_allowed(s, pgroups[i], SSL_SECOP_CURVE_SUPPORTED))
675                 continue;
676 
677             curve_id = pgroups[i];
678             break;
679         }
680     }
681 
682     if (curve_id == 0) {
683         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE,
684                  SSL_R_NO_SUITABLE_KEY_SHARE);
685         return EXT_RETURN_FAIL;
686     }
687 
688     if (!add_key_share(s, pkt, curve_id)) {
689         /* SSLfatal() already called */
690         return EXT_RETURN_FAIL;
691     }
692 
693     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
694         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE,
695                  ERR_R_INTERNAL_ERROR);
696         return EXT_RETURN_FAIL;
697     }
698     return EXT_RETURN_SENT;
699 #else
700     return EXT_RETURN_NOT_SENT;
701 #endif
702 }
703 
704 EXT_RETURN tls_construct_ctos_cookie(SSL *s, WPACKET *pkt, unsigned int context,
705                                      X509 *x, size_t chainidx)
706 {
707     EXT_RETURN ret = EXT_RETURN_FAIL;
708 
709     /* Should only be set if we've had an HRR */
710     if (s->ext.tls13_cookie_len == 0)
711         return EXT_RETURN_NOT_SENT;
712 
713     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_cookie)
714                /* Extension data sub-packet */
715             || !WPACKET_start_sub_packet_u16(pkt)
716             || !WPACKET_sub_memcpy_u16(pkt, s->ext.tls13_cookie,
717                                        s->ext.tls13_cookie_len)
718             || !WPACKET_close(pkt)) {
719         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_COOKIE,
720                  ERR_R_INTERNAL_ERROR);
721         goto end;
722     }
723 
724     ret = EXT_RETURN_SENT;
725  end:
726     OPENSSL_free(s->ext.tls13_cookie);
727     s->ext.tls13_cookie = NULL;
728     s->ext.tls13_cookie_len = 0;
729 
730     return ret;
731 }
732 
733 EXT_RETURN tls_construct_ctos_early_data(SSL *s, WPACKET *pkt,
734                                          unsigned int context, X509 *x,
735                                          size_t chainidx)
736 {
737 #ifndef OPENSSL_NO_PSK
738     char identity[PSK_MAX_IDENTITY_LEN + 1];
739 #endif  /* OPENSSL_NO_PSK */
740     const unsigned char *id = NULL;
741     size_t idlen = 0;
742     SSL_SESSION *psksess = NULL;
743     SSL_SESSION *edsess = NULL;
744     const EVP_MD *handmd = NULL;
745 
746     if (s->hello_retry_request == SSL_HRR_PENDING)
747         handmd = ssl_handshake_md(s);
748 
749     if (s->psk_use_session_cb != NULL
750             && (!s->psk_use_session_cb(s, handmd, &id, &idlen, &psksess)
751                 || (psksess != NULL
752                     && psksess->ssl_version != TLS1_3_VERSION))) {
753         SSL_SESSION_free(psksess);
754         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
755                  SSL_R_BAD_PSK);
756         return EXT_RETURN_FAIL;
757     }
758 
759 #ifndef OPENSSL_NO_PSK
760     if (psksess == NULL && s->psk_client_callback != NULL) {
761         unsigned char psk[PSK_MAX_PSK_LEN];
762         size_t psklen = 0;
763 
764         memset(identity, 0, sizeof(identity));
765         psklen = s->psk_client_callback(s, NULL, identity, sizeof(identity) - 1,
766                                         psk, sizeof(psk));
767 
768         if (psklen > PSK_MAX_PSK_LEN) {
769             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
770                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
771             return EXT_RETURN_FAIL;
772         } else if (psklen > 0) {
773             const unsigned char tls13_aes128gcmsha256_id[] = { 0x13, 0x01 };
774             const SSL_CIPHER *cipher;
775 
776             idlen = strlen(identity);
777             if (idlen > PSK_MAX_IDENTITY_LEN) {
778                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
779                          SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
780                          ERR_R_INTERNAL_ERROR);
781                 return EXT_RETURN_FAIL;
782             }
783             id = (unsigned char *)identity;
784 
785             /*
786              * We found a PSK using an old style callback. We don't know
787              * the digest so we default to SHA256 as per the TLSv1.3 spec
788              */
789             cipher = SSL_CIPHER_find(s, tls13_aes128gcmsha256_id);
790             if (cipher == NULL) {
791                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
792                          SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
793                          ERR_R_INTERNAL_ERROR);
794                 return EXT_RETURN_FAIL;
795             }
796 
797             psksess = SSL_SESSION_new();
798             if (psksess == NULL
799                     || !SSL_SESSION_set1_master_key(psksess, psk, psklen)
800                     || !SSL_SESSION_set_cipher(psksess, cipher)
801                     || !SSL_SESSION_set_protocol_version(psksess, TLS1_3_VERSION)) {
802                 SSLfatal(s, SSL_AD_INTERNAL_ERROR,
803                          SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
804                          ERR_R_INTERNAL_ERROR);
805                 OPENSSL_cleanse(psk, psklen);
806                 return EXT_RETURN_FAIL;
807             }
808             OPENSSL_cleanse(psk, psklen);
809         }
810     }
811 #endif  /* OPENSSL_NO_PSK */
812 
813     SSL_SESSION_free(s->psksession);
814     s->psksession = psksess;
815     if (psksess != NULL) {
816         OPENSSL_free(s->psksession_id);
817         s->psksession_id = OPENSSL_memdup(id, idlen);
818         if (s->psksession_id == NULL) {
819             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
820                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
821             return EXT_RETURN_FAIL;
822         }
823         s->psksession_id_len = idlen;
824     }
825 
826     if (s->early_data_state != SSL_EARLY_DATA_CONNECTING
827             || (s->session->ext.max_early_data == 0
828                 && (psksess == NULL || psksess->ext.max_early_data == 0))) {
829         s->max_early_data = 0;
830         return EXT_RETURN_NOT_SENT;
831     }
832     edsess = s->session->ext.max_early_data != 0 ? s->session : psksess;
833     s->max_early_data = edsess->ext.max_early_data;
834 
835     if (edsess->ext.hostname != NULL) {
836         if (s->ext.hostname == NULL
837                 || (s->ext.hostname != NULL
838                     && strcmp(s->ext.hostname, edsess->ext.hostname) != 0)) {
839             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
840                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
841                      SSL_R_INCONSISTENT_EARLY_DATA_SNI);
842             return EXT_RETURN_FAIL;
843         }
844     }
845 
846     if ((s->ext.alpn == NULL && edsess->ext.alpn_selected != NULL)) {
847         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
848                  SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
849         return EXT_RETURN_FAIL;
850     }
851 
852     /*
853      * Verify that we are offering an ALPN protocol consistent with the early
854      * data.
855      */
856     if (edsess->ext.alpn_selected != NULL) {
857         PACKET prots, alpnpkt;
858         int found = 0;
859 
860         if (!PACKET_buf_init(&prots, s->ext.alpn, s->ext.alpn_len)) {
861             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
862                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
863             return EXT_RETURN_FAIL;
864         }
865         while (PACKET_get_length_prefixed_1(&prots, &alpnpkt)) {
866             if (PACKET_equal(&alpnpkt, edsess->ext.alpn_selected,
867                              edsess->ext.alpn_selected_len)) {
868                 found = 1;
869                 break;
870             }
871         }
872         if (!found) {
873             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
874                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
875                      SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
876             return EXT_RETURN_FAIL;
877         }
878     }
879 
880     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
881             || !WPACKET_start_sub_packet_u16(pkt)
882             || !WPACKET_close(pkt)) {
883         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
884                  ERR_R_INTERNAL_ERROR);
885         return EXT_RETURN_FAIL;
886     }
887 
888     /*
889      * We set this to rejected here. Later, if the server acknowledges the
890      * extension, we set it to accepted.
891      */
892     s->ext.early_data = SSL_EARLY_DATA_REJECTED;
893     s->ext.early_data_ok = 1;
894 
895     return EXT_RETURN_SENT;
896 }
897 
898 #define F5_WORKAROUND_MIN_MSG_LEN   0xff
899 #define F5_WORKAROUND_MAX_MSG_LEN   0x200
900 
901 /*
902  * PSK pre binder overhead =
903  *  2 bytes for TLSEXT_TYPE_psk
904  *  2 bytes for extension length
905  *  2 bytes for identities list length
906  *  2 bytes for identity length
907  *  4 bytes for obfuscated_ticket_age
908  *  2 bytes for binder list length
909  *  1 byte for binder length
910  * The above excludes the number of bytes for the identity itself and the
911  * subsequent binder bytes
912  */
913 #define PSK_PRE_BINDER_OVERHEAD (2 + 2 + 2 + 2 + 4 + 2 + 1)
914 
915 EXT_RETURN tls_construct_ctos_padding(SSL *s, WPACKET *pkt,
916                                       unsigned int context, X509 *x,
917                                       size_t chainidx)
918 {
919     unsigned char *padbytes;
920     size_t hlen;
921 
922     if ((s->options & SSL_OP_TLSEXT_PADDING) == 0)
923         return EXT_RETURN_NOT_SENT;
924 
925     /*
926      * Add padding to workaround bugs in F5 terminators. See RFC7685.
927      * This code calculates the length of all extensions added so far but
928      * excludes the PSK extension (because that MUST be written last). Therefore
929      * this extension MUST always appear second to last.
930      */
931     if (!WPACKET_get_total_written(pkt, &hlen)) {
932         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PADDING,
933                  ERR_R_INTERNAL_ERROR);
934         return EXT_RETURN_FAIL;
935     }
936 
937     /*
938      * If we're going to send a PSK then that will be written out after this
939      * extension, so we need to calculate how long it is going to be.
940      */
941     if (s->session->ssl_version == TLS1_3_VERSION
942             && s->session->ext.ticklen != 0
943             && s->session->cipher != NULL) {
944         const EVP_MD *md = ssl_md(s->session->cipher->algorithm2);
945 
946         if (md != NULL) {
947             /*
948              * Add the fixed PSK overhead, the identity length and the binder
949              * length.
950              */
951             hlen +=  PSK_PRE_BINDER_OVERHEAD + s->session->ext.ticklen
952                      + EVP_MD_size(md);
953         }
954     }
955 
956     if (hlen > F5_WORKAROUND_MIN_MSG_LEN && hlen < F5_WORKAROUND_MAX_MSG_LEN) {
957         /* Calculate the amount of padding we need to add */
958         hlen = F5_WORKAROUND_MAX_MSG_LEN - hlen;
959 
960         /*
961          * Take off the size of extension header itself (2 bytes for type and
962          * 2 bytes for length bytes), but ensure that the extension is at least
963          * 1 byte long so as not to have an empty extension last (WebSphere 7.x,
964          * 8.x are intolerant of that condition)
965          */
966         if (hlen > 4)
967             hlen -= 4;
968         else
969             hlen = 1;
970 
971         if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_padding)
972                 || !WPACKET_sub_allocate_bytes_u16(pkt, hlen, &padbytes)) {
973             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PADDING,
974                      ERR_R_INTERNAL_ERROR);
975             return EXT_RETURN_FAIL;
976         }
977         memset(padbytes, 0, hlen);
978     }
979 
980     return EXT_RETURN_SENT;
981 }
982 
983 /*
984  * Construct the pre_shared_key extension
985  */
986 EXT_RETURN tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context,
987                                   X509 *x, size_t chainidx)
988 {
989 #ifndef OPENSSL_NO_TLS1_3
990     uint32_t now, agesec, agems = 0;
991     size_t reshashsize = 0, pskhashsize = 0, binderoffset, msglen;
992     unsigned char *resbinder = NULL, *pskbinder = NULL, *msgstart = NULL;
993     const EVP_MD *handmd = NULL, *mdres = NULL, *mdpsk = NULL;
994     int dores = 0;
995 
996     s->ext.tick_identity = 0;
997 
998     /*
999      * Note: At this stage of the code we only support adding a single
1000      * resumption PSK. If we add support for multiple PSKs then the length
1001      * calculations in the padding extension will need to be adjusted.
1002      */
1003 
1004     /*
1005      * If this is an incompatible or new session then we have nothing to resume
1006      * so don't add this extension.
1007      */
1008     if (s->session->ssl_version != TLS1_3_VERSION
1009             || (s->session->ext.ticklen == 0 && s->psksession == NULL))
1010         return EXT_RETURN_NOT_SENT;
1011 
1012     if (s->hello_retry_request == SSL_HRR_PENDING)
1013         handmd = ssl_handshake_md(s);
1014 
1015     if (s->session->ext.ticklen != 0) {
1016         /* Get the digest associated with the ciphersuite in the session */
1017         if (s->session->cipher == NULL) {
1018             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1019                      ERR_R_INTERNAL_ERROR);
1020             return EXT_RETURN_FAIL;
1021         }
1022         mdres = ssl_md(s->session->cipher->algorithm2);
1023         if (mdres == NULL) {
1024             /*
1025              * Don't recognize this cipher so we can't use the session.
1026              * Ignore it
1027              */
1028             goto dopsksess;
1029         }
1030 
1031         if (s->hello_retry_request == SSL_HRR_PENDING && mdres != handmd) {
1032             /*
1033              * Selected ciphersuite hash does not match the hash for the session
1034              * so we can't use it.
1035              */
1036             goto dopsksess;
1037         }
1038 
1039         /*
1040          * Technically the C standard just says time() returns a time_t and says
1041          * nothing about the encoding of that type. In practice most
1042          * implementations follow POSIX which holds it as an integral type in
1043          * seconds since epoch. We've already made the assumption that we can do
1044          * this in multiple places in the code, so portability shouldn't be an
1045          * issue.
1046          */
1047         now = (uint32_t)time(NULL);
1048         agesec = now - (uint32_t)s->session->time;
1049         /*
1050          * We calculate the age in seconds but the server may work in ms. Due to
1051          * rounding errors we could overestimate the age by up to 1s. It is
1052          * better to underestimate it. Otherwise, if the RTT is very short, when
1053          * the server calculates the age reported by the client it could be
1054          * bigger than the age calculated on the server - which should never
1055          * happen.
1056          */
1057         if (agesec > 0)
1058             agesec--;
1059 
1060         if (s->session->ext.tick_lifetime_hint < agesec) {
1061             /* Ticket is too old. Ignore it. */
1062             goto dopsksess;
1063         }
1064 
1065         /*
1066          * Calculate age in ms. We're just doing it to nearest second. Should be
1067          * good enough.
1068          */
1069         agems = agesec * (uint32_t)1000;
1070 
1071         if (agesec != 0 && agems / (uint32_t)1000 != agesec) {
1072             /*
1073              * Overflow. Shouldn't happen unless this is a *really* old session.
1074              * If so we just ignore it.
1075              */
1076             goto dopsksess;
1077         }
1078 
1079         /*
1080          * Obfuscate the age. Overflow here is fine, this addition is supposed
1081          * to be mod 2^32.
1082          */
1083         agems += s->session->ext.tick_age_add;
1084 
1085         reshashsize = EVP_MD_size(mdres);
1086         s->ext.tick_identity++;
1087         dores = 1;
1088     }
1089 
1090  dopsksess:
1091     if (!dores && s->psksession == NULL)
1092         return EXT_RETURN_NOT_SENT;
1093 
1094     if (s->psksession != NULL) {
1095         mdpsk = ssl_md(s->psksession->cipher->algorithm2);
1096         if (mdpsk == NULL) {
1097             /*
1098              * Don't recognize this cipher so we can't use the session.
1099              * If this happens it's an application bug.
1100              */
1101             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1102                      SSL_R_BAD_PSK);
1103             return EXT_RETURN_FAIL;
1104         }
1105 
1106         if (s->hello_retry_request == SSL_HRR_PENDING && mdpsk != handmd) {
1107             /*
1108              * Selected ciphersuite hash does not match the hash for the PSK
1109              * session. This is an application bug.
1110              */
1111             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1112                      SSL_R_BAD_PSK);
1113             return EXT_RETURN_FAIL;
1114         }
1115 
1116         pskhashsize = EVP_MD_size(mdpsk);
1117     }
1118 
1119     /* Create the extension, but skip over the binder for now */
1120     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
1121             || !WPACKET_start_sub_packet_u16(pkt)
1122             || !WPACKET_start_sub_packet_u16(pkt)) {
1123         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1124                  ERR_R_INTERNAL_ERROR);
1125         return EXT_RETURN_FAIL;
1126     }
1127 
1128     if (dores) {
1129         if (!WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick,
1130                                            s->session->ext.ticklen)
1131                 || !WPACKET_put_bytes_u32(pkt, agems)) {
1132             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1133                      ERR_R_INTERNAL_ERROR);
1134             return EXT_RETURN_FAIL;
1135         }
1136     }
1137 
1138     if (s->psksession != NULL) {
1139         if (!WPACKET_sub_memcpy_u16(pkt, s->psksession_id,
1140                                     s->psksession_id_len)
1141                 || !WPACKET_put_bytes_u32(pkt, 0)) {
1142             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1143                      ERR_R_INTERNAL_ERROR);
1144             return EXT_RETURN_FAIL;
1145         }
1146         s->ext.tick_identity++;
1147     }
1148 
1149     if (!WPACKET_close(pkt)
1150             || !WPACKET_get_total_written(pkt, &binderoffset)
1151             || !WPACKET_start_sub_packet_u16(pkt)
1152             || (dores
1153                 && !WPACKET_sub_allocate_bytes_u8(pkt, reshashsize, &resbinder))
1154             || (s->psksession != NULL
1155                 && !WPACKET_sub_allocate_bytes_u8(pkt, pskhashsize, &pskbinder))
1156             || !WPACKET_close(pkt)
1157             || !WPACKET_close(pkt)
1158             || !WPACKET_get_total_written(pkt, &msglen)
1159                /*
1160                 * We need to fill in all the sub-packet lengths now so we can
1161                 * calculate the HMAC of the message up to the binders
1162                 */
1163             || !WPACKET_fill_lengths(pkt)) {
1164         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1165                  ERR_R_INTERNAL_ERROR);
1166         return EXT_RETURN_FAIL;
1167     }
1168 
1169     msgstart = WPACKET_get_curr(pkt) - msglen;
1170 
1171     if (dores
1172             && tls_psk_do_binder(s, mdres, msgstart, binderoffset, NULL,
1173                                  resbinder, s->session, 1, 0) != 1) {
1174         /* SSLfatal() already called */
1175         return EXT_RETURN_FAIL;
1176     }
1177 
1178     if (s->psksession != NULL
1179             && tls_psk_do_binder(s, mdpsk, msgstart, binderoffset, NULL,
1180                                  pskbinder, s->psksession, 1, 1) != 1) {
1181         /* SSLfatal() already called */
1182         return EXT_RETURN_FAIL;
1183     }
1184 
1185     return EXT_RETURN_SENT;
1186 #else
1187     return EXT_RETURN_NOT_SENT;
1188 #endif
1189 }
1190 
1191 EXT_RETURN tls_construct_ctos_post_handshake_auth(SSL *s, WPACKET *pkt,
1192                                                   unsigned int context,
1193                                                   X509 *x, size_t chainidx)
1194 {
1195 #ifndef OPENSSL_NO_TLS1_3
1196     if (!s->pha_enabled)
1197         return EXT_RETURN_NOT_SENT;
1198 
1199     /* construct extension - 0 length, no contents */
1200     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_post_handshake_auth)
1201             || !WPACKET_start_sub_packet_u16(pkt)
1202             || !WPACKET_close(pkt)) {
1203         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1204                  SSL_F_TLS_CONSTRUCT_CTOS_POST_HANDSHAKE_AUTH,
1205                  ERR_R_INTERNAL_ERROR);
1206         return EXT_RETURN_FAIL;
1207     }
1208 
1209     s->post_handshake_auth = SSL_PHA_EXT_SENT;
1210 
1211     return EXT_RETURN_SENT;
1212 #else
1213     return EXT_RETURN_NOT_SENT;
1214 #endif
1215 }
1216 
1217 
1218 /*
1219  * Parse the server's renegotiation binding and abort if it's not right
1220  */
1221 int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
1222                                X509 *x, size_t chainidx)
1223 {
1224     size_t expected_len = s->s3->previous_client_finished_len
1225         + s->s3->previous_server_finished_len;
1226     size_t ilen;
1227     const unsigned char *data;
1228 
1229     /* Check for logic errors */
1230     if (!ossl_assert(expected_len == 0
1231                      || s->s3->previous_client_finished_len != 0)
1232         || !ossl_assert(expected_len == 0
1233                         || s->s3->previous_server_finished_len != 0)) {
1234         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1235                  ERR_R_INTERNAL_ERROR);
1236         return 0;
1237     }
1238 
1239     /* Parse the length byte */
1240     if (!PACKET_get_1_len(pkt, &ilen)) {
1241         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1242                  SSL_R_RENEGOTIATION_ENCODING_ERR);
1243         return 0;
1244     }
1245 
1246     /* Consistency check */
1247     if (PACKET_remaining(pkt) != ilen) {
1248         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1249                  SSL_R_RENEGOTIATION_ENCODING_ERR);
1250         return 0;
1251     }
1252 
1253     /* Check that the extension matches */
1254     if (ilen != expected_len) {
1255         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1256                  SSL_R_RENEGOTIATION_MISMATCH);
1257         return 0;
1258     }
1259 
1260     if (!PACKET_get_bytes(pkt, &data, s->s3->previous_client_finished_len)
1261         || memcmp(data, s->s3->previous_client_finished,
1262                   s->s3->previous_client_finished_len) != 0) {
1263         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1264                  SSL_R_RENEGOTIATION_MISMATCH);
1265         return 0;
1266     }
1267 
1268     if (!PACKET_get_bytes(pkt, &data, s->s3->previous_server_finished_len)
1269         || memcmp(data, s->s3->previous_server_finished,
1270                   s->s3->previous_server_finished_len) != 0) {
1271         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1272                  SSL_R_RENEGOTIATION_MISMATCH);
1273         return 0;
1274     }
1275     s->s3->send_connection_binding = 1;
1276 
1277     return 1;
1278 }
1279 
1280 /* Parse the server's max fragment len extension packet */
1281 int tls_parse_stoc_maxfragmentlen(SSL *s, PACKET *pkt, unsigned int context,
1282                                   X509 *x, size_t chainidx)
1283 {
1284     unsigned int value;
1285 
1286     if (PACKET_remaining(pkt) != 1 || !PACKET_get_1(pkt, &value)) {
1287         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_MAXFRAGMENTLEN,
1288                  SSL_R_BAD_EXTENSION);
1289         return 0;
1290     }
1291 
1292     /* |value| should contains a valid max-fragment-length code. */
1293     if (!IS_MAX_FRAGMENT_LENGTH_EXT_VALID(value)) {
1294         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1295                  SSL_F_TLS_PARSE_STOC_MAXFRAGMENTLEN,
1296                  SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
1297         return 0;
1298     }
1299 
1300     /* Must be the same value as client-configured one who was sent to server */
1301     /*-
1302      * RFC 6066: if a client receives a maximum fragment length negotiation
1303      * response that differs from the length it requested, ...
1304      * It must abort with SSL_AD_ILLEGAL_PARAMETER alert
1305      */
1306     if (value != s->ext.max_fragment_len_mode) {
1307         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1308                  SSL_F_TLS_PARSE_STOC_MAXFRAGMENTLEN,
1309                  SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
1310         return 0;
1311     }
1312 
1313     /*
1314      * Maximum Fragment Length Negotiation succeeded.
1315      * The negotiated Maximum Fragment Length is binding now.
1316      */
1317     s->session->ext.max_fragment_len_mode = value;
1318 
1319     return 1;
1320 }
1321 
1322 int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, unsigned int context,
1323                                X509 *x, size_t chainidx)
1324 {
1325     if (s->ext.hostname == NULL) {
1326         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1327                  ERR_R_INTERNAL_ERROR);
1328         return 0;
1329     }
1330 
1331     if (PACKET_remaining(pkt) > 0) {
1332         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1333                  SSL_R_BAD_EXTENSION);
1334         return 0;
1335     }
1336 
1337     if (!s->hit) {
1338         if (s->session->ext.hostname != NULL) {
1339             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1340                      ERR_R_INTERNAL_ERROR);
1341             return 0;
1342         }
1343         s->session->ext.hostname = OPENSSL_strdup(s->ext.hostname);
1344         if (s->session->ext.hostname == NULL) {
1345             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1346                      ERR_R_INTERNAL_ERROR);
1347             return 0;
1348         }
1349     }
1350 
1351     return 1;
1352 }
1353 
1354 #ifndef OPENSSL_NO_EC
1355 int tls_parse_stoc_ec_pt_formats(SSL *s, PACKET *pkt, unsigned int context,
1356                                  X509 *x, size_t chainidx)
1357 {
1358     size_t ecpointformats_len;
1359     PACKET ecptformatlist;
1360 
1361     if (!PACKET_as_length_prefixed_1(pkt, &ecptformatlist)) {
1362         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS,
1363                  SSL_R_BAD_EXTENSION);
1364         return 0;
1365     }
1366     if (!s->hit) {
1367         ecpointformats_len = PACKET_remaining(&ecptformatlist);
1368         if (ecpointformats_len == 0) {
1369             SSLfatal(s, SSL_AD_DECODE_ERROR,
1370                      SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS, SSL_R_BAD_LENGTH);
1371             return 0;
1372         }
1373 
1374         s->ext.peer_ecpointformats_len = 0;
1375         OPENSSL_free(s->ext.peer_ecpointformats);
1376         s->ext.peer_ecpointformats = OPENSSL_malloc(ecpointformats_len);
1377         if (s->ext.peer_ecpointformats == NULL) {
1378             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1379                      SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
1380             return 0;
1381         }
1382 
1383         s->ext.peer_ecpointformats_len = ecpointformats_len;
1384 
1385         if (!PACKET_copy_bytes(&ecptformatlist,
1386                                s->ext.peer_ecpointformats,
1387                                ecpointformats_len)) {
1388             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1389                      SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
1390             return 0;
1391         }
1392     }
1393 
1394     return 1;
1395 }
1396 #endif
1397 
1398 int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
1399                                   X509 *x, size_t chainidx)
1400 {
1401     if (s->ext.session_ticket_cb != NULL &&
1402         !s->ext.session_ticket_cb(s, PACKET_data(pkt),
1403                               PACKET_remaining(pkt),
1404                               s->ext.session_ticket_cb_arg)) {
1405         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1406                  SSL_F_TLS_PARSE_STOC_SESSION_TICKET, SSL_R_BAD_EXTENSION);
1407         return 0;
1408     }
1409 
1410     if (!tls_use_ticket(s)) {
1411         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION,
1412                  SSL_F_TLS_PARSE_STOC_SESSION_TICKET, SSL_R_BAD_EXTENSION);
1413         return 0;
1414     }
1415     if (PACKET_remaining(pkt) > 0) {
1416         SSLfatal(s, SSL_AD_DECODE_ERROR,
1417                  SSL_F_TLS_PARSE_STOC_SESSION_TICKET, SSL_R_BAD_EXTENSION);
1418         return 0;
1419     }
1420 
1421     s->ext.ticket_expected = 1;
1422 
1423     return 1;
1424 }
1425 
1426 #ifndef OPENSSL_NO_OCSP
1427 int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, unsigned int context,
1428                                   X509 *x, size_t chainidx)
1429 {
1430     if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST) {
1431         /* We ignore this if the server sends a CertificateRequest */
1432         /* TODO(TLS1.3): Add support for this */
1433         return 1;
1434     }
1435 
1436     /*
1437      * MUST only be sent if we've requested a status
1438      * request message. In TLS <= 1.2 it must also be empty.
1439      */
1440     if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp) {
1441         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION,
1442                  SSL_F_TLS_PARSE_STOC_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
1443         return 0;
1444     }
1445     if (!SSL_IS_TLS13(s) && PACKET_remaining(pkt) > 0) {
1446         SSLfatal(s, SSL_AD_DECODE_ERROR,
1447                  SSL_F_TLS_PARSE_STOC_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
1448         return 0;
1449     }
1450 
1451     if (SSL_IS_TLS13(s)) {
1452         /* We only know how to handle this if it's for the first Certificate in
1453          * the chain. We ignore any other responses.
1454          */
1455         if (chainidx != 0)
1456             return 1;
1457 
1458         /* SSLfatal() already called */
1459         return tls_process_cert_status_body(s, pkt);
1460     }
1461 
1462     /* Set flag to expect CertificateStatus message */
1463     s->ext.status_expected = 1;
1464 
1465     return 1;
1466 }
1467 #endif
1468 
1469 
1470 #ifndef OPENSSL_NO_CT
1471 int tls_parse_stoc_sct(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1472                        size_t chainidx)
1473 {
1474     if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST) {
1475         /* We ignore this if the server sends it in a CertificateRequest */
1476         /* TODO(TLS1.3): Add support for this */
1477         return 1;
1478     }
1479 
1480     /*
1481      * Only take it if we asked for it - i.e if there is no CT validation
1482      * callback set, then a custom extension MAY be processing it, so we
1483      * need to let control continue to flow to that.
1484      */
1485     if (s->ct_validation_callback != NULL) {
1486         size_t size = PACKET_remaining(pkt);
1487 
1488         /* Simply copy it off for later processing */
1489         OPENSSL_free(s->ext.scts);
1490         s->ext.scts = NULL;
1491 
1492         s->ext.scts_len = (uint16_t)size;
1493         if (size > 0) {
1494             s->ext.scts = OPENSSL_malloc(size);
1495             if (s->ext.scts == NULL
1496                     || !PACKET_copy_bytes(pkt, s->ext.scts, size)) {
1497                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SCT,
1498                          ERR_R_INTERNAL_ERROR);
1499                 return 0;
1500             }
1501         }
1502     } else {
1503         ENDPOINT role = (context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0
1504                         ? ENDPOINT_CLIENT : ENDPOINT_BOTH;
1505 
1506         /*
1507          * If we didn't ask for it then there must be a custom extension,
1508          * otherwise this is unsolicited.
1509          */
1510         if (custom_ext_find(&s->cert->custext, role,
1511                             TLSEXT_TYPE_signed_certificate_timestamp,
1512                             NULL) == NULL) {
1513             SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_F_TLS_PARSE_STOC_SCT,
1514                      SSL_R_BAD_EXTENSION);
1515             return 0;
1516         }
1517 
1518         if (!custom_ext_parse(s, context,
1519                              TLSEXT_TYPE_signed_certificate_timestamp,
1520                              PACKET_data(pkt), PACKET_remaining(pkt),
1521                              x, chainidx)) {
1522             /* SSLfatal already called */
1523             return 0;
1524         }
1525     }
1526 
1527     return 1;
1528 }
1529 #endif
1530 
1531 
1532 #ifndef OPENSSL_NO_NEXTPROTONEG
1533 /*
1534  * ssl_next_proto_validate validates a Next Protocol Negotiation block. No
1535  * elements of zero length are allowed and the set of elements must exactly
1536  * fill the length of the block. Returns 1 on success or 0 on failure.
1537  */
1538 static int ssl_next_proto_validate(SSL *s, PACKET *pkt)
1539 {
1540     PACKET tmp_protocol;
1541 
1542     while (PACKET_remaining(pkt)) {
1543         if (!PACKET_get_length_prefixed_1(pkt, &tmp_protocol)
1544             || PACKET_remaining(&tmp_protocol) == 0) {
1545             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL_NEXT_PROTO_VALIDATE,
1546                      SSL_R_BAD_EXTENSION);
1547             return 0;
1548         }
1549     }
1550 
1551     return 1;
1552 }
1553 
1554 int tls_parse_stoc_npn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1555                        size_t chainidx)
1556 {
1557     unsigned char *selected;
1558     unsigned char selected_len;
1559     PACKET tmppkt;
1560 
1561     /* Check if we are in a renegotiation. If so ignore this extension */
1562     if (!SSL_IS_FIRST_HANDSHAKE(s))
1563         return 1;
1564 
1565     /* We must have requested it. */
1566     if (s->ctx->ext.npn_select_cb == NULL) {
1567         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_F_TLS_PARSE_STOC_NPN,
1568                  SSL_R_BAD_EXTENSION);
1569         return 0;
1570     }
1571 
1572     /* The data must be valid */
1573     tmppkt = *pkt;
1574     if (!ssl_next_proto_validate(s, &tmppkt)) {
1575         /* SSLfatal() already called */
1576         return 0;
1577     }
1578     if (s->ctx->ext.npn_select_cb(s, &selected, &selected_len,
1579                                   PACKET_data(pkt),
1580                                   PACKET_remaining(pkt),
1581                                   s->ctx->ext.npn_select_cb_arg) !=
1582              SSL_TLSEXT_ERR_OK) {
1583         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PARSE_STOC_NPN,
1584                  SSL_R_BAD_EXTENSION);
1585         return 0;
1586     }
1587 
1588     /*
1589      * Could be non-NULL if server has sent multiple NPN extensions in
1590      * a single Serverhello
1591      */
1592     OPENSSL_free(s->ext.npn);
1593     s->ext.npn = OPENSSL_malloc(selected_len);
1594     if (s->ext.npn == NULL) {
1595         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_NPN,
1596                  ERR_R_INTERNAL_ERROR);
1597         return 0;
1598     }
1599 
1600     memcpy(s->ext.npn, selected, selected_len);
1601     s->ext.npn_len = selected_len;
1602     s->s3->npn_seen = 1;
1603 
1604     return 1;
1605 }
1606 #endif
1607 
1608 int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1609                         size_t chainidx)
1610 {
1611     size_t len;
1612 
1613     /* We must have requested it. */
1614     if (!s->s3->alpn_sent) {
1615         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_F_TLS_PARSE_STOC_ALPN,
1616                  SSL_R_BAD_EXTENSION);
1617         return 0;
1618     }
1619     /*-
1620      * The extension data consists of:
1621      *   uint16 list_length
1622      *   uint8 proto_length;
1623      *   uint8 proto[proto_length];
1624      */
1625     if (!PACKET_get_net_2_len(pkt, &len)
1626         || PACKET_remaining(pkt) != len || !PACKET_get_1_len(pkt, &len)
1627         || PACKET_remaining(pkt) != len) {
1628         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1629                  SSL_R_BAD_EXTENSION);
1630         return 0;
1631     }
1632     OPENSSL_free(s->s3->alpn_selected);
1633     s->s3->alpn_selected = OPENSSL_malloc(len);
1634     if (s->s3->alpn_selected == NULL) {
1635         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1636                  ERR_R_INTERNAL_ERROR);
1637         return 0;
1638     }
1639     if (!PACKET_copy_bytes(pkt, s->s3->alpn_selected, len)) {
1640         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1641                  SSL_R_BAD_EXTENSION);
1642         return 0;
1643     }
1644     s->s3->alpn_selected_len = len;
1645 
1646     if (s->session->ext.alpn_selected == NULL
1647             || s->session->ext.alpn_selected_len != len
1648             || memcmp(s->session->ext.alpn_selected, s->s3->alpn_selected, len)
1649                != 0) {
1650         /* ALPN not consistent with the old session so cannot use early_data */
1651         s->ext.early_data_ok = 0;
1652     }
1653     if (!s->hit) {
1654         /*
1655          * This is a new session and so alpn_selected should have been
1656          * initialised to NULL. We should update it with the selected ALPN.
1657          */
1658         if (!ossl_assert(s->session->ext.alpn_selected == NULL)) {
1659             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1660                      ERR_R_INTERNAL_ERROR);
1661             return 0;
1662         }
1663         s->session->ext.alpn_selected =
1664             OPENSSL_memdup(s->s3->alpn_selected, s->s3->alpn_selected_len);
1665         if (s->session->ext.alpn_selected == NULL) {
1666             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1667                      ERR_R_INTERNAL_ERROR);
1668             return 0;
1669         }
1670         s->session->ext.alpn_selected_len = s->s3->alpn_selected_len;
1671     }
1672 
1673     return 1;
1674 }
1675 
1676 #ifndef OPENSSL_NO_SRTP
1677 int tls_parse_stoc_use_srtp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1678                             size_t chainidx)
1679 {
1680     unsigned int id, ct, mki;
1681     int i;
1682     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
1683     SRTP_PROTECTION_PROFILE *prof;
1684 
1685     if (!PACKET_get_net_2(pkt, &ct) || ct != 2
1686             || !PACKET_get_net_2(pkt, &id)
1687             || !PACKET_get_1(pkt, &mki)
1688             || PACKET_remaining(pkt) != 0) {
1689         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1690                  SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
1691         return 0;
1692     }
1693 
1694     if (mki != 0) {
1695         /* Must be no MKI, since we never offer one */
1696         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1697                  SSL_R_BAD_SRTP_MKI_VALUE);
1698         return 0;
1699     }
1700 
1701     /* Throw an error if the server gave us an unsolicited extension */
1702     clnt = SSL_get_srtp_profiles(s);
1703     if (clnt == NULL) {
1704         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1705                  SSL_R_NO_SRTP_PROFILES);
1706         return 0;
1707     }
1708 
1709     /*
1710      * Check to see if the server gave us something we support (and
1711      * presumably offered)
1712      */
1713     for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) {
1714         prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
1715 
1716         if (prof->id == id) {
1717             s->srtp_profile = prof;
1718             return 1;
1719         }
1720     }
1721 
1722     SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1723              SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
1724     return 0;
1725 }
1726 #endif
1727 
1728 int tls_parse_stoc_etm(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1729                        size_t chainidx)
1730 {
1731     /* Ignore if inappropriate ciphersuite */
1732     if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
1733             && s->s3->tmp.new_cipher->algorithm_mac != SSL_AEAD
1734             && s->s3->tmp.new_cipher->algorithm_enc != SSL_RC4)
1735         s->ext.use_etm = 1;
1736 
1737     return 1;
1738 }
1739 
1740 int tls_parse_stoc_ems(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1741                        size_t chainidx)
1742 {
1743     s->s3->flags |= TLS1_FLAGS_RECEIVED_EXTMS;
1744     if (!s->hit)
1745         s->session->flags |= SSL_SESS_FLAG_EXTMS;
1746 
1747     return 1;
1748 }
1749 
1750 int tls_parse_stoc_supported_versions(SSL *s, PACKET *pkt, unsigned int context,
1751                                       X509 *x, size_t chainidx)
1752 {
1753     unsigned int version;
1754 
1755     if (!PACKET_get_net_2(pkt, &version)
1756             || PACKET_remaining(pkt) != 0) {
1757         SSLfatal(s, SSL_AD_DECODE_ERROR,
1758                  SSL_F_TLS_PARSE_STOC_SUPPORTED_VERSIONS,
1759                  SSL_R_LENGTH_MISMATCH);
1760         return 0;
1761     }
1762 
1763     /*
1764      * The only protocol version we support which is valid in this extension in
1765      * a ServerHello is TLSv1.3 therefore we shouldn't be getting anything else.
1766      */
1767     if (version != TLS1_3_VERSION) {
1768         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1769                  SSL_F_TLS_PARSE_STOC_SUPPORTED_VERSIONS,
1770                  SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
1771         return 0;
1772     }
1773 
1774     /* We ignore this extension for HRRs except to sanity check it */
1775     if (context == SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)
1776         return 1;
1777 
1778     /* We just set it here. We validate it in ssl_choose_client_version */
1779     s->version = version;
1780 
1781     return 1;
1782 }
1783 
1784 int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1785                              size_t chainidx)
1786 {
1787 #ifndef OPENSSL_NO_TLS1_3
1788     unsigned int group_id;
1789     PACKET encoded_pt;
1790     EVP_PKEY *ckey = s->s3->tmp.pkey, *skey = NULL;
1791 
1792     /* Sanity check */
1793     if (ckey == NULL || s->s3->peer_tmp != NULL) {
1794         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1795                  ERR_R_INTERNAL_ERROR);
1796         return 0;
1797     }
1798 
1799     if (!PACKET_get_net_2(pkt, &group_id)) {
1800         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1801                  SSL_R_LENGTH_MISMATCH);
1802         return 0;
1803     }
1804 
1805     if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0) {
1806         const uint16_t *pgroups = NULL;
1807         size_t i, num_groups;
1808 
1809         if (PACKET_remaining(pkt) != 0) {
1810             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1811                      SSL_R_LENGTH_MISMATCH);
1812             return 0;
1813         }
1814 
1815         /*
1816          * It is an error if the HelloRetryRequest wants a key_share that we
1817          * already sent in the first ClientHello
1818          */
1819         if (group_id == s->s3->group_id) {
1820             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1821                      SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
1822             return 0;
1823         }
1824 
1825         /* Validate the selected group is one we support */
1826         tls1_get_supported_groups(s, &pgroups, &num_groups);
1827         for (i = 0; i < num_groups; i++) {
1828             if (group_id == pgroups[i])
1829                 break;
1830         }
1831         if (i >= num_groups
1832                 || !tls_curve_allowed(s, group_id, SSL_SECOP_CURVE_SUPPORTED)) {
1833             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1834                      SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
1835             return 0;
1836         }
1837 
1838         s->s3->group_id = group_id;
1839         EVP_PKEY_free(s->s3->tmp.pkey);
1840         s->s3->tmp.pkey = NULL;
1841         return 1;
1842     }
1843 
1844     if (group_id != s->s3->group_id) {
1845         /*
1846          * This isn't for the group that we sent in the original
1847          * key_share!
1848          */
1849         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1850                  SSL_R_BAD_KEY_SHARE);
1851         return 0;
1852     }
1853 
1854     if (!PACKET_as_length_prefixed_2(pkt, &encoded_pt)
1855             || PACKET_remaining(&encoded_pt) == 0) {
1856         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1857                  SSL_R_LENGTH_MISMATCH);
1858         return 0;
1859     }
1860 
1861     skey = EVP_PKEY_new();
1862     if (skey == NULL || EVP_PKEY_copy_parameters(skey, ckey) <= 0) {
1863         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1864                  ERR_R_MALLOC_FAILURE);
1865         return 0;
1866     }
1867     if (!EVP_PKEY_set1_tls_encodedpoint(skey, PACKET_data(&encoded_pt),
1868                                         PACKET_remaining(&encoded_pt))) {
1869         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1870                  SSL_R_BAD_ECPOINT);
1871         EVP_PKEY_free(skey);
1872         return 0;
1873     }
1874 
1875     if (ssl_derive(s, ckey, skey, 1) == 0) {
1876         /* SSLfatal() already called */
1877         EVP_PKEY_free(skey);
1878         return 0;
1879     }
1880     s->s3->peer_tmp = skey;
1881 #endif
1882 
1883     return 1;
1884 }
1885 
1886 int tls_parse_stoc_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1887                        size_t chainidx)
1888 {
1889     PACKET cookie;
1890 
1891     if (!PACKET_as_length_prefixed_2(pkt, &cookie)
1892             || !PACKET_memdup(&cookie, &s->ext.tls13_cookie,
1893                               &s->ext.tls13_cookie_len)) {
1894         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_COOKIE,
1895                  SSL_R_LENGTH_MISMATCH);
1896         return 0;
1897     }
1898 
1899     return 1;
1900 }
1901 
1902 int tls_parse_stoc_early_data(SSL *s, PACKET *pkt, unsigned int context,
1903                               X509 *x, size_t chainidx)
1904 {
1905     if (context == SSL_EXT_TLS1_3_NEW_SESSION_TICKET) {
1906         unsigned long max_early_data;
1907 
1908         if (!PACKET_get_net_4(pkt, &max_early_data)
1909                 || PACKET_remaining(pkt) != 0) {
1910             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_EARLY_DATA,
1911                      SSL_R_INVALID_MAX_EARLY_DATA);
1912             return 0;
1913         }
1914 
1915         s->session->ext.max_early_data = max_early_data;
1916 
1917         return 1;
1918     }
1919 
1920     if (PACKET_remaining(pkt) != 0) {
1921         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_EARLY_DATA,
1922                  SSL_R_BAD_EXTENSION);
1923         return 0;
1924     }
1925 
1926     if (!s->ext.early_data_ok
1927             || !s->hit) {
1928         /*
1929          * If we get here then we didn't send early data, or we didn't resume
1930          * using the first identity, or the SNI/ALPN is not consistent so the
1931          * server should not be accepting it.
1932          */
1933         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_EARLY_DATA,
1934                  SSL_R_BAD_EXTENSION);
1935         return 0;
1936     }
1937 
1938     s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1939 
1940     return 1;
1941 }
1942 
1943 int tls_parse_stoc_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1944                        size_t chainidx)
1945 {
1946 #ifndef OPENSSL_NO_TLS1_3
1947     unsigned int identity;
1948 
1949     if (!PACKET_get_net_2(pkt, &identity) || PACKET_remaining(pkt) != 0) {
1950         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_PSK,
1951                  SSL_R_LENGTH_MISMATCH);
1952         return 0;
1953     }
1954 
1955     if (identity >= (unsigned int)s->ext.tick_identity) {
1956         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_PSK,
1957                  SSL_R_BAD_PSK_IDENTITY);
1958         return 0;
1959     }
1960 
1961     /*
1962      * Session resumption tickets are always sent before PSK tickets. If the
1963      * ticket index is 0 then it must be for a session resumption ticket if we
1964      * sent two tickets, or if we didn't send a PSK ticket.
1965      */
1966     if (identity == 0 && (s->psksession == NULL || s->ext.tick_identity == 2)) {
1967         s->hit = 1;
1968         SSL_SESSION_free(s->psksession);
1969         s->psksession = NULL;
1970         return 1;
1971     }
1972 
1973     if (s->psksession == NULL) {
1974         /* Should never happen */
1975         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_PSK,
1976                  ERR_R_INTERNAL_ERROR);
1977         return 0;
1978     }
1979 
1980     /*
1981      * If we used the external PSK for sending early_data then s->early_secret
1982      * is already set up, so don't overwrite it. Otherwise we copy the
1983      * early_secret across that we generated earlier.
1984      */
1985     if ((s->early_data_state != SSL_EARLY_DATA_WRITE_RETRY
1986                 && s->early_data_state != SSL_EARLY_DATA_FINISHED_WRITING)
1987             || s->session->ext.max_early_data > 0
1988             || s->psksession->ext.max_early_data == 0)
1989         memcpy(s->early_secret, s->psksession->early_secret, EVP_MAX_MD_SIZE);
1990 
1991     SSL_SESSION_free(s->session);
1992     s->session = s->psksession;
1993     s->psksession = NULL;
1994     s->hit = 1;
1995     /* Early data is only allowed if we used the first ticket */
1996     if (identity != 0)
1997         s->ext.early_data_ok = 0;
1998 #endif
1999 
2000     return 1;
2001 }
2002