xref: /freebsd/crypto/openssl/ssl/statem/extensions_clnt.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
1 /*
2  * Copyright 2016-2022 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (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_local.h"
12 #include "internal/cryptlib.h"
13 #include "statem_local.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, ERR_R_INTERNAL_ERROR);
29         return EXT_RETURN_FAIL;
30     }
31 
32     return EXT_RETURN_SENT;
33 }
34 
35 EXT_RETURN tls_construct_ctos_server_name(SSL *s, WPACKET *pkt,
36                                           unsigned int context, X509 *x,
37                                           size_t chainidx)
38 {
39     if (s->ext.hostname == NULL)
40         return EXT_RETURN_NOT_SENT;
41 
42     /* Add TLS extension servername to the Client Hello message */
43     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_server_name)
44                /* Sub-packet for server_name extension */
45             || !WPACKET_start_sub_packet_u16(pkt)
46                /* Sub-packet for servername list (always 1 hostname)*/
47             || !WPACKET_start_sub_packet_u16(pkt)
48             || !WPACKET_put_bytes_u8(pkt, TLSEXT_NAMETYPE_host_name)
49             || !WPACKET_sub_memcpy_u16(pkt, s->ext.hostname,
50                                        strlen(s->ext.hostname))
51             || !WPACKET_close(pkt)
52             || !WPACKET_close(pkt)) {
53         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
54         return EXT_RETURN_FAIL;
55     }
56 
57     return EXT_RETURN_SENT;
58 }
59 
60 /* Push a Max Fragment Len extension into ClientHello */
61 EXT_RETURN tls_construct_ctos_maxfragmentlen(SSL *s, WPACKET *pkt,
62                                              unsigned int context, X509 *x,
63                                              size_t chainidx)
64 {
65     if (s->ext.max_fragment_len_mode == TLSEXT_max_fragment_length_DISABLED)
66         return EXT_RETURN_NOT_SENT;
67 
68     /* Add Max Fragment Length extension if client enabled it. */
69     /*-
70      * 4 bytes for this extension type and extension length
71      * 1 byte for the Max Fragment Length code value.
72      */
73     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_max_fragment_length)
74             /* Sub-packet for Max Fragment Length extension (1 byte) */
75             || !WPACKET_start_sub_packet_u16(pkt)
76             || !WPACKET_put_bytes_u8(pkt, s->ext.max_fragment_len_mode)
77             || !WPACKET_close(pkt)) {
78         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
79         return EXT_RETURN_FAIL;
80     }
81 
82     return EXT_RETURN_SENT;
83 }
84 
85 #ifndef OPENSSL_NO_SRP
86 EXT_RETURN tls_construct_ctos_srp(SSL *s, WPACKET *pkt, unsigned int context,
87                                   X509 *x, size_t chainidx)
88 {
89     /* Add SRP username if there is one */
90     if (s->srp_ctx.login == NULL)
91         return EXT_RETURN_NOT_SENT;
92 
93     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_srp)
94                /* Sub-packet for SRP extension */
95             || !WPACKET_start_sub_packet_u16(pkt)
96             || !WPACKET_start_sub_packet_u8(pkt)
97                /* login must not be zero...internal error if so */
98             || !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)
99             || !WPACKET_memcpy(pkt, s->srp_ctx.login,
100                                strlen(s->srp_ctx.login))
101             || !WPACKET_close(pkt)
102             || !WPACKET_close(pkt)) {
103         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
104         return EXT_RETURN_FAIL;
105     }
106 
107     return EXT_RETURN_SENT;
108 }
109 #endif
110 
111 static int use_ecc(SSL *s, int min_version, int max_version)
112 {
113     int i, end, ret = 0;
114     unsigned long alg_k, alg_a;
115     STACK_OF(SSL_CIPHER) *cipher_stack = NULL;
116     const uint16_t *pgroups = NULL;
117     size_t num_groups, j;
118 
119     /* See if we support any ECC ciphersuites */
120     if (s->version == SSL3_VERSION)
121         return 0;
122 
123     cipher_stack = SSL_get1_supported_ciphers(s);
124     end = sk_SSL_CIPHER_num(cipher_stack);
125     for (i = 0; i < end; i++) {
126         const SSL_CIPHER *c = sk_SSL_CIPHER_value(cipher_stack, i);
127 
128         alg_k = c->algorithm_mkey;
129         alg_a = c->algorithm_auth;
130         if ((alg_k & (SSL_kECDHE | SSL_kECDHEPSK))
131                 || (alg_a & SSL_aECDSA)
132                 || c->min_tls >= TLS1_3_VERSION) {
133             ret = 1;
134             break;
135         }
136     }
137     sk_SSL_CIPHER_free(cipher_stack);
138     if (!ret)
139         return 0;
140 
141     /* Check we have at least one EC supported group */
142     tls1_get_supported_groups(s, &pgroups, &num_groups);
143     for (j = 0; j < num_groups; j++) {
144         uint16_t ctmp = pgroups[j];
145 
146         if (tls_valid_group(s, ctmp, min_version, max_version, 1, NULL)
147                 && tls_group_allowed(s, ctmp, SSL_SECOP_CURVE_SUPPORTED))
148             return 1;
149     }
150 
151     return 0;
152 }
153 
154 EXT_RETURN tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt,
155                                             unsigned int context, X509 *x,
156                                             size_t chainidx)
157 {
158     const unsigned char *pformats;
159     size_t num_formats;
160     int reason, min_version, max_version;
161 
162     reason = ssl_get_min_max_version(s, &min_version, &max_version, NULL);
163     if (reason != 0) {
164         SSLfatal(s, SSL_AD_INTERNAL_ERROR, reason);
165         return EXT_RETURN_FAIL;
166     }
167     if (!use_ecc(s, min_version, max_version))
168         return EXT_RETURN_NOT_SENT;
169 
170     /* Add TLS extension ECPointFormats to the ClientHello message */
171     tls1_get_formatlist(s, &pformats, &num_formats);
172 
173     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_ec_point_formats)
174                /* Sub-packet for formats extension */
175             || !WPACKET_start_sub_packet_u16(pkt)
176             || !WPACKET_sub_memcpy_u8(pkt, pformats, num_formats)
177             || !WPACKET_close(pkt)) {
178         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
179         return EXT_RETURN_FAIL;
180     }
181 
182     return EXT_RETURN_SENT;
183 }
184 
185 EXT_RETURN tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
186                                                unsigned int context, X509 *x,
187                                                size_t chainidx)
188 {
189     const uint16_t *pgroups = NULL;
190     size_t num_groups = 0, i, tls13added = 0, added = 0;
191     int min_version, max_version, reason;
192 
193     reason = ssl_get_min_max_version(s, &min_version, &max_version, NULL);
194     if (reason != 0) {
195         SSLfatal(s, SSL_AD_INTERNAL_ERROR, reason);
196         return EXT_RETURN_FAIL;
197     }
198 
199     /*
200      * We only support EC groups in TLSv1.2 or below, and in DTLS. Therefore
201      * if we don't have EC support then we don't send this extension.
202      */
203     if (!use_ecc(s, min_version, max_version)
204             && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
205         return EXT_RETURN_NOT_SENT;
206 
207     /*
208      * Add TLS extension supported_groups to the ClientHello message
209      */
210     tls1_get_supported_groups(s, &pgroups, &num_groups);
211 
212     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_groups)
213                /* Sub-packet for supported_groups extension */
214             || !WPACKET_start_sub_packet_u16(pkt)
215             || !WPACKET_start_sub_packet_u16(pkt)
216             || !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)) {
217         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
218         return EXT_RETURN_FAIL;
219     }
220     /* Copy group ID if supported */
221     for (i = 0; i < num_groups; i++) {
222         uint16_t ctmp = pgroups[i];
223         int okfortls13;
224 
225         if (tls_valid_group(s, ctmp, min_version, max_version, 0, &okfortls13)
226                 && tls_group_allowed(s, ctmp, SSL_SECOP_CURVE_SUPPORTED)) {
227             if (!WPACKET_put_bytes_u16(pkt, ctmp)) {
228                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
229                 return EXT_RETURN_FAIL;
230             }
231             if (okfortls13 && max_version == TLS1_3_VERSION)
232                 tls13added++;
233             added++;
234         }
235     }
236     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
237         if (added == 0)
238             SSLfatal_data(s, SSL_AD_INTERNAL_ERROR, SSL_R_NO_SUITABLE_GROUPS,
239                           "No groups enabled for max supported SSL/TLS version");
240         else
241             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
242         return EXT_RETURN_FAIL;
243     }
244 
245     if (tls13added == 0 && max_version == TLS1_3_VERSION) {
246         SSLfatal_data(s, SSL_AD_INTERNAL_ERROR, SSL_R_NO_SUITABLE_GROUPS,
247                       "No groups enabled for max supported SSL/TLS version");
248         return EXT_RETURN_FAIL;
249     }
250 
251     return EXT_RETURN_SENT;
252 }
253 
254 EXT_RETURN tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt,
255                                              unsigned int context, X509 *x,
256                                              size_t chainidx)
257 {
258     size_t ticklen;
259 
260     if (!tls_use_ticket(s))
261         return EXT_RETURN_NOT_SENT;
262 
263     if (!s->new_session && s->session != NULL
264             && s->session->ext.tick != NULL
265             && s->session->ssl_version != TLS1_3_VERSION) {
266         ticklen = s->session->ext.ticklen;
267     } else if (s->session && s->ext.session_ticket != NULL
268                && s->ext.session_ticket->data != NULL) {
269         ticklen = s->ext.session_ticket->length;
270         s->session->ext.tick = OPENSSL_malloc(ticklen);
271         if (s->session->ext.tick == NULL) {
272             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
273             return EXT_RETURN_FAIL;
274         }
275         memcpy(s->session->ext.tick,
276                s->ext.session_ticket->data, ticklen);
277         s->session->ext.ticklen = ticklen;
278     } else {
279         ticklen = 0;
280     }
281 
282     if (ticklen == 0 && s->ext.session_ticket != NULL &&
283             s->ext.session_ticket->data == NULL)
284         return EXT_RETURN_NOT_SENT;
285 
286     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_session_ticket)
287             || !WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick, ticklen)) {
288         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
289         return EXT_RETURN_FAIL;
290     }
291 
292     return EXT_RETURN_SENT;
293 }
294 
295 EXT_RETURN tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt,
296                                        unsigned int context, X509 *x,
297                                        size_t chainidx)
298 {
299     size_t salglen;
300     const uint16_t *salg;
301 
302     if (!SSL_CLIENT_USE_SIGALGS(s))
303         return EXT_RETURN_NOT_SENT;
304 
305     salglen = tls12_get_psigalgs(s, 1, &salg);
306     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_signature_algorithms)
307                /* Sub-packet for sig-algs extension */
308             || !WPACKET_start_sub_packet_u16(pkt)
309                /* Sub-packet for the actual list */
310             || !WPACKET_start_sub_packet_u16(pkt)
311             || !tls12_copy_sigalgs(s, pkt, salg, salglen)
312             || !WPACKET_close(pkt)
313             || !WPACKET_close(pkt)) {
314         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
315         return EXT_RETURN_FAIL;
316     }
317 
318     return EXT_RETURN_SENT;
319 }
320 
321 #ifndef OPENSSL_NO_OCSP
322 EXT_RETURN tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
323                                              unsigned int context, X509 *x,
324                                              size_t chainidx)
325 {
326     int i;
327 
328     /* This extension isn't defined for client Certificates */
329     if (x != NULL)
330         return EXT_RETURN_NOT_SENT;
331 
332     if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp)
333         return EXT_RETURN_NOT_SENT;
334 
335     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
336                /* Sub-packet for status request extension */
337             || !WPACKET_start_sub_packet_u16(pkt)
338             || !WPACKET_put_bytes_u8(pkt, TLSEXT_STATUSTYPE_ocsp)
339                /* Sub-packet for the ids */
340             || !WPACKET_start_sub_packet_u16(pkt)) {
341         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
342         return EXT_RETURN_FAIL;
343     }
344     for (i = 0; i < sk_OCSP_RESPID_num(s->ext.ocsp.ids); i++) {
345         unsigned char *idbytes;
346         OCSP_RESPID *id = sk_OCSP_RESPID_value(s->ext.ocsp.ids, i);
347         int idlen = i2d_OCSP_RESPID(id, NULL);
348 
349         if (idlen <= 0
350                    /* Sub-packet for an individual id */
351                 || !WPACKET_sub_allocate_bytes_u16(pkt, idlen, &idbytes)
352                 || i2d_OCSP_RESPID(id, &idbytes) != idlen) {
353             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
354             return EXT_RETURN_FAIL;
355         }
356     }
357     if (!WPACKET_close(pkt)
358             || !WPACKET_start_sub_packet_u16(pkt)) {
359         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
360         return EXT_RETURN_FAIL;
361     }
362     if (s->ext.ocsp.exts) {
363         unsigned char *extbytes;
364         int extlen = i2d_X509_EXTENSIONS(s->ext.ocsp.exts, NULL);
365 
366         if (extlen < 0) {
367             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
368             return EXT_RETURN_FAIL;
369         }
370         if (!WPACKET_allocate_bytes(pkt, extlen, &extbytes)
371                 || i2d_X509_EXTENSIONS(s->ext.ocsp.exts, &extbytes)
372                    != extlen) {
373             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
374             return EXT_RETURN_FAIL;
375        }
376     }
377     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
378         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
379         return EXT_RETURN_FAIL;
380     }
381 
382     return EXT_RETURN_SENT;
383 }
384 #endif
385 
386 #ifndef OPENSSL_NO_NEXTPROTONEG
387 EXT_RETURN tls_construct_ctos_npn(SSL *s, WPACKET *pkt, unsigned int context,
388                                   X509 *x, size_t chainidx)
389 {
390     if (s->ctx->ext.npn_select_cb == NULL || !SSL_IS_FIRST_HANDSHAKE(s))
391         return EXT_RETURN_NOT_SENT;
392 
393     /*
394      * The client advertises an empty extension to indicate its support
395      * for Next Protocol Negotiation
396      */
397     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_next_proto_neg)
398             || !WPACKET_put_bytes_u16(pkt, 0)) {
399         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
400         return EXT_RETURN_FAIL;
401     }
402 
403     return EXT_RETURN_SENT;
404 }
405 #endif
406 
407 EXT_RETURN tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, unsigned int context,
408                                    X509 *x, size_t chainidx)
409 {
410     s->s3.alpn_sent = 0;
411 
412     if (s->ext.alpn == NULL || !SSL_IS_FIRST_HANDSHAKE(s))
413         return EXT_RETURN_NOT_SENT;
414 
415     if (!WPACKET_put_bytes_u16(pkt,
416                 TLSEXT_TYPE_application_layer_protocol_negotiation)
417                /* Sub-packet ALPN extension */
418             || !WPACKET_start_sub_packet_u16(pkt)
419             || !WPACKET_sub_memcpy_u16(pkt, s->ext.alpn, s->ext.alpn_len)
420             || !WPACKET_close(pkt)) {
421         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
422         return EXT_RETURN_FAIL;
423     }
424     s->s3.alpn_sent = 1;
425 
426     return EXT_RETURN_SENT;
427 }
428 
429 
430 #ifndef OPENSSL_NO_SRTP
431 EXT_RETURN tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt,
432                                        unsigned int context, X509 *x,
433                                        size_t chainidx)
434 {
435     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = SSL_get_srtp_profiles(s);
436     int i, end;
437 
438     if (clnt == NULL)
439         return EXT_RETURN_NOT_SENT;
440 
441     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_use_srtp)
442                /* Sub-packet for SRTP extension */
443             || !WPACKET_start_sub_packet_u16(pkt)
444                /* Sub-packet for the protection profile list */
445             || !WPACKET_start_sub_packet_u16(pkt)) {
446         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
447         return EXT_RETURN_FAIL;
448     }
449 
450     end = sk_SRTP_PROTECTION_PROFILE_num(clnt);
451     for (i = 0; i < end; i++) {
452         const SRTP_PROTECTION_PROFILE *prof =
453             sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
454 
455         if (prof == NULL || !WPACKET_put_bytes_u16(pkt, prof->id)) {
456             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
457             return EXT_RETURN_FAIL;
458         }
459     }
460     if (!WPACKET_close(pkt)
461                /* Add an empty use_mki value */
462             || !WPACKET_put_bytes_u8(pkt, 0)
463             || !WPACKET_close(pkt)) {
464         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
465         return EXT_RETURN_FAIL;
466     }
467 
468     return EXT_RETURN_SENT;
469 }
470 #endif
471 
472 EXT_RETURN tls_construct_ctos_etm(SSL *s, WPACKET *pkt, unsigned int context,
473                                   X509 *x, size_t chainidx)
474 {
475     if (s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
476         return EXT_RETURN_NOT_SENT;
477 
478     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_encrypt_then_mac)
479             || !WPACKET_put_bytes_u16(pkt, 0)) {
480         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
481         return EXT_RETURN_FAIL;
482     }
483 
484     return EXT_RETURN_SENT;
485 }
486 
487 #ifndef OPENSSL_NO_CT
488 EXT_RETURN tls_construct_ctos_sct(SSL *s, WPACKET *pkt, unsigned int context,
489                                   X509 *x, size_t chainidx)
490 {
491     if (s->ct_validation_callback == NULL)
492         return EXT_RETURN_NOT_SENT;
493 
494     /* Not defined for client Certificates */
495     if (x != NULL)
496         return EXT_RETURN_NOT_SENT;
497 
498     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_signed_certificate_timestamp)
499             || !WPACKET_put_bytes_u16(pkt, 0)) {
500         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
501         return EXT_RETURN_FAIL;
502     }
503 
504     return EXT_RETURN_SENT;
505 }
506 #endif
507 
508 EXT_RETURN tls_construct_ctos_ems(SSL *s, WPACKET *pkt, unsigned int context,
509                                   X509 *x, size_t chainidx)
510 {
511     if (s->options & SSL_OP_NO_EXTENDED_MASTER_SECRET)
512         return EXT_RETURN_NOT_SENT;
513 
514     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
515             || !WPACKET_put_bytes_u16(pkt, 0)) {
516         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
517         return EXT_RETURN_FAIL;
518     }
519 
520     return EXT_RETURN_SENT;
521 }
522 
523 EXT_RETURN tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
524                                                  unsigned int context, X509 *x,
525                                                  size_t chainidx)
526 {
527     int currv, min_version, max_version, reason;
528 
529     reason = ssl_get_min_max_version(s, &min_version, &max_version, NULL);
530     if (reason != 0) {
531         SSLfatal(s, SSL_AD_INTERNAL_ERROR, reason);
532         return EXT_RETURN_FAIL;
533     }
534 
535     /*
536      * Don't include this if we can't negotiate TLSv1.3. We can do a straight
537      * comparison here because we will never be called in DTLS.
538      */
539     if (max_version < TLS1_3_VERSION)
540         return EXT_RETURN_NOT_SENT;
541 
542     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_versions)
543             || !WPACKET_start_sub_packet_u16(pkt)
544             || !WPACKET_start_sub_packet_u8(pkt)) {
545         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
546         return EXT_RETURN_FAIL;
547     }
548 
549     for (currv = max_version; currv >= min_version; currv--) {
550         if (!WPACKET_put_bytes_u16(pkt, currv)) {
551             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
552             return EXT_RETURN_FAIL;
553         }
554     }
555     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
556         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
557         return EXT_RETURN_FAIL;
558     }
559 
560     return EXT_RETURN_SENT;
561 }
562 
563 /*
564  * Construct a psk_kex_modes extension.
565  */
566 EXT_RETURN tls_construct_ctos_psk_kex_modes(SSL *s, WPACKET *pkt,
567                                             unsigned int context, X509 *x,
568                                             size_t chainidx)
569 {
570 #ifndef OPENSSL_NO_TLS1_3
571     int nodhe = s->options & SSL_OP_ALLOW_NO_DHE_KEX;
572 
573     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk_kex_modes)
574             || !WPACKET_start_sub_packet_u16(pkt)
575             || !WPACKET_start_sub_packet_u8(pkt)
576             || !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE_DHE)
577             || (nodhe && !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE))
578             || !WPACKET_close(pkt)
579             || !WPACKET_close(pkt)) {
580         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
581         return EXT_RETURN_FAIL;
582     }
583 
584     s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_KE_DHE;
585     if (nodhe)
586         s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE;
587 #endif
588 
589     return EXT_RETURN_SENT;
590 }
591 
592 #ifndef OPENSSL_NO_TLS1_3
593 static int add_key_share(SSL *s, WPACKET *pkt, unsigned int curve_id)
594 {
595     unsigned char *encoded_point = NULL;
596     EVP_PKEY *key_share_key = NULL;
597     size_t encodedlen;
598 
599     if (s->s3.tmp.pkey != NULL) {
600         if (!ossl_assert(s->hello_retry_request == SSL_HRR_PENDING)) {
601             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
602             return 0;
603         }
604         /*
605          * Could happen if we got an HRR that wasn't requesting a new key_share
606          */
607         key_share_key = s->s3.tmp.pkey;
608     } else {
609         key_share_key = ssl_generate_pkey_group(s, curve_id);
610         if (key_share_key == NULL) {
611             /* SSLfatal() already called */
612             return 0;
613         }
614     }
615 
616     /* Encode the public key. */
617     encodedlen = EVP_PKEY_get1_encoded_public_key(key_share_key,
618                                                   &encoded_point);
619     if (encodedlen == 0) {
620         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_EC_LIB);
621         goto err;
622     }
623 
624     /* Create KeyShareEntry */
625     if (!WPACKET_put_bytes_u16(pkt, curve_id)
626             || !WPACKET_sub_memcpy_u16(pkt, encoded_point, encodedlen)) {
627         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
628         goto err;
629     }
630 
631     /*
632      * When changing to send more than one key_share we're
633      * going to need to be able to save more than one EVP_PKEY. For now
634      * we reuse the existing tmp.pkey
635      */
636     s->s3.tmp.pkey = key_share_key;
637     s->s3.group_id = curve_id;
638     OPENSSL_free(encoded_point);
639 
640     return 1;
641  err:
642     if (s->s3.tmp.pkey == NULL)
643         EVP_PKEY_free(key_share_key);
644     OPENSSL_free(encoded_point);
645     return 0;
646 }
647 #endif
648 
649 EXT_RETURN tls_construct_ctos_key_share(SSL *s, WPACKET *pkt,
650                                         unsigned int context, X509 *x,
651                                         size_t chainidx)
652 {
653 #ifndef OPENSSL_NO_TLS1_3
654     size_t i, num_groups = 0;
655     const uint16_t *pgroups = NULL;
656     uint16_t curve_id = 0;
657 
658     /* key_share extension */
659     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
660                /* Extension data sub-packet */
661             || !WPACKET_start_sub_packet_u16(pkt)
662                /* KeyShare list sub-packet */
663             || !WPACKET_start_sub_packet_u16(pkt)) {
664         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
665         return EXT_RETURN_FAIL;
666     }
667 
668     tls1_get_supported_groups(s, &pgroups, &num_groups);
669 
670     /*
671      * Make the number of key_shares sent configurable. For
672      * now, we just send one
673      */
674     if (s->s3.group_id != 0) {
675         curve_id = s->s3.group_id;
676     } else {
677         for (i = 0; i < num_groups; i++) {
678 
679             if (!tls_group_allowed(s, pgroups[i], SSL_SECOP_CURVE_SUPPORTED))
680                 continue;
681 
682             if (!tls_valid_group(s, pgroups[i], TLS1_3_VERSION, TLS1_3_VERSION,
683                                  0, NULL))
684                 continue;
685 
686             curve_id = pgroups[i];
687             break;
688         }
689     }
690 
691     if (curve_id == 0) {
692         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_NO_SUITABLE_KEY_SHARE);
693         return EXT_RETURN_FAIL;
694     }
695 
696     if (!add_key_share(s, pkt, curve_id)) {
697         /* SSLfatal() already called */
698         return EXT_RETURN_FAIL;
699     }
700 
701     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
702         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
703         return EXT_RETURN_FAIL;
704     }
705     return EXT_RETURN_SENT;
706 #else
707     return EXT_RETURN_NOT_SENT;
708 #endif
709 }
710 
711 EXT_RETURN tls_construct_ctos_cookie(SSL *s, WPACKET *pkt, unsigned int context,
712                                      X509 *x, size_t chainidx)
713 {
714     EXT_RETURN ret = EXT_RETURN_FAIL;
715 
716     /* Should only be set if we've had an HRR */
717     if (s->ext.tls13_cookie_len == 0)
718         return EXT_RETURN_NOT_SENT;
719 
720     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_cookie)
721                /* Extension data sub-packet */
722             || !WPACKET_start_sub_packet_u16(pkt)
723             || !WPACKET_sub_memcpy_u16(pkt, s->ext.tls13_cookie,
724                                        s->ext.tls13_cookie_len)
725             || !WPACKET_close(pkt)) {
726         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
727         goto end;
728     }
729 
730     ret = EXT_RETURN_SENT;
731  end:
732     OPENSSL_free(s->ext.tls13_cookie);
733     s->ext.tls13_cookie = NULL;
734     s->ext.tls13_cookie_len = 0;
735 
736     return ret;
737 }
738 
739 EXT_RETURN tls_construct_ctos_early_data(SSL *s, WPACKET *pkt,
740                                          unsigned int context, X509 *x,
741                                          size_t chainidx)
742 {
743 #ifndef OPENSSL_NO_PSK
744     char identity[PSK_MAX_IDENTITY_LEN + 1];
745 #endif  /* OPENSSL_NO_PSK */
746     const unsigned char *id = NULL;
747     size_t idlen = 0;
748     SSL_SESSION *psksess = NULL;
749     SSL_SESSION *edsess = NULL;
750     const EVP_MD *handmd = NULL;
751 
752     if (s->hello_retry_request == SSL_HRR_PENDING)
753         handmd = ssl_handshake_md(s);
754 
755     if (s->psk_use_session_cb != NULL
756             && (!s->psk_use_session_cb(s, handmd, &id, &idlen, &psksess)
757                 || (psksess != NULL
758                     && psksess->ssl_version != TLS1_3_VERSION))) {
759         SSL_SESSION_free(psksess);
760         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_PSK);
761         return EXT_RETURN_FAIL;
762     }
763 
764 #ifndef OPENSSL_NO_PSK
765     if (psksess == NULL && s->psk_client_callback != NULL) {
766         unsigned char psk[PSK_MAX_PSK_LEN];
767         size_t psklen = 0;
768 
769         memset(identity, 0, sizeof(identity));
770         psklen = s->psk_client_callback(s, NULL, identity, sizeof(identity) - 1,
771                                         psk, sizeof(psk));
772 
773         if (psklen > PSK_MAX_PSK_LEN) {
774             SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, ERR_R_INTERNAL_ERROR);
775             return EXT_RETURN_FAIL;
776         } else if (psklen > 0) {
777             const unsigned char tls13_aes128gcmsha256_id[] = { 0x13, 0x01 };
778             const SSL_CIPHER *cipher;
779 
780             idlen = strlen(identity);
781             if (idlen > PSK_MAX_IDENTITY_LEN) {
782                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
783                 return EXT_RETURN_FAIL;
784             }
785             id = (unsigned char *)identity;
786 
787             /*
788              * We found a PSK using an old style callback. We don't know
789              * the digest so we default to SHA256 as per the TLSv1.3 spec
790              */
791             cipher = SSL_CIPHER_find(s, tls13_aes128gcmsha256_id);
792             if (cipher == NULL) {
793                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 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, ERR_R_INTERNAL_ERROR);
803                 OPENSSL_cleanse(psk, psklen);
804                 return EXT_RETURN_FAIL;
805             }
806             OPENSSL_cleanse(psk, psklen);
807         }
808     }
809 #endif  /* OPENSSL_NO_PSK */
810 
811     SSL_SESSION_free(s->psksession);
812     s->psksession = psksess;
813     if (psksess != NULL) {
814         OPENSSL_free(s->psksession_id);
815         s->psksession_id = OPENSSL_memdup(id, idlen);
816         if (s->psksession_id == NULL) {
817             s->psksession_id_len = 0;
818             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
819             return EXT_RETURN_FAIL;
820         }
821         s->psksession_id_len = idlen;
822     }
823 
824     if (s->early_data_state != SSL_EARLY_DATA_CONNECTING
825             || (s->session->ext.max_early_data == 0
826                 && (psksess == NULL || psksess->ext.max_early_data == 0))) {
827         s->max_early_data = 0;
828         return EXT_RETURN_NOT_SENT;
829     }
830     edsess = s->session->ext.max_early_data != 0 ? s->session : psksess;
831     s->max_early_data = edsess->ext.max_early_data;
832 
833     if (edsess->ext.hostname != NULL) {
834         if (s->ext.hostname == NULL
835                 || (s->ext.hostname != NULL
836                     && strcmp(s->ext.hostname, edsess->ext.hostname) != 0)) {
837             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
838                      SSL_R_INCONSISTENT_EARLY_DATA_SNI);
839             return EXT_RETURN_FAIL;
840         }
841     }
842 
843     if ((s->ext.alpn == NULL && edsess->ext.alpn_selected != NULL)) {
844         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
845         return EXT_RETURN_FAIL;
846     }
847 
848     /*
849      * Verify that we are offering an ALPN protocol consistent with the early
850      * data.
851      */
852     if (edsess->ext.alpn_selected != NULL) {
853         PACKET prots, alpnpkt;
854         int found = 0;
855 
856         if (!PACKET_buf_init(&prots, s->ext.alpn, s->ext.alpn_len)) {
857             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
858             return EXT_RETURN_FAIL;
859         }
860         while (PACKET_get_length_prefixed_1(&prots, &alpnpkt)) {
861             if (PACKET_equal(&alpnpkt, edsess->ext.alpn_selected,
862                              edsess->ext.alpn_selected_len)) {
863                 found = 1;
864                 break;
865             }
866         }
867         if (!found) {
868             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
869                      SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
870             return EXT_RETURN_FAIL;
871         }
872     }
873 
874     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
875             || !WPACKET_start_sub_packet_u16(pkt)
876             || !WPACKET_close(pkt)) {
877         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
878         return EXT_RETURN_FAIL;
879     }
880 
881     /*
882      * We set this to rejected here. Later, if the server acknowledges the
883      * extension, we set it to accepted.
884      */
885     s->ext.early_data = SSL_EARLY_DATA_REJECTED;
886     s->ext.early_data_ok = 1;
887 
888     return EXT_RETURN_SENT;
889 }
890 
891 #define F5_WORKAROUND_MIN_MSG_LEN   0xff
892 #define F5_WORKAROUND_MAX_MSG_LEN   0x200
893 
894 /*
895  * PSK pre binder overhead =
896  *  2 bytes for TLSEXT_TYPE_psk
897  *  2 bytes for extension length
898  *  2 bytes for identities list length
899  *  2 bytes for identity length
900  *  4 bytes for obfuscated_ticket_age
901  *  2 bytes for binder list length
902  *  1 byte for binder length
903  * The above excludes the number of bytes for the identity itself and the
904  * subsequent binder bytes
905  */
906 #define PSK_PRE_BINDER_OVERHEAD (2 + 2 + 2 + 2 + 4 + 2 + 1)
907 
908 EXT_RETURN tls_construct_ctos_padding(SSL *s, WPACKET *pkt,
909                                       unsigned int context, X509 *x,
910                                       size_t chainidx)
911 {
912     unsigned char *padbytes;
913     size_t hlen;
914 
915     if ((s->options & SSL_OP_TLSEXT_PADDING) == 0)
916         return EXT_RETURN_NOT_SENT;
917 
918     /*
919      * Add padding to workaround bugs in F5 terminators. See RFC7685.
920      * This code calculates the length of all extensions added so far but
921      * excludes the PSK extension (because that MUST be written last). Therefore
922      * this extension MUST always appear second to last.
923      */
924     if (!WPACKET_get_total_written(pkt, &hlen)) {
925         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
926         return EXT_RETURN_FAIL;
927     }
928 
929     /*
930      * If we're going to send a PSK then that will be written out after this
931      * extension, so we need to calculate how long it is going to be.
932      */
933     if (s->session->ssl_version == TLS1_3_VERSION
934             && s->session->ext.ticklen != 0
935             && s->session->cipher != NULL) {
936         const EVP_MD *md = ssl_md(s->ctx, s->session->cipher->algorithm2);
937 
938         if (md != NULL) {
939             /*
940              * Add the fixed PSK overhead, the identity length and the binder
941              * length.
942              */
943             hlen +=  PSK_PRE_BINDER_OVERHEAD + s->session->ext.ticklen
944                      + EVP_MD_get_size(md);
945         }
946     }
947 
948     if (hlen > F5_WORKAROUND_MIN_MSG_LEN && hlen < F5_WORKAROUND_MAX_MSG_LEN) {
949         /* Calculate the amount of padding we need to add */
950         hlen = F5_WORKAROUND_MAX_MSG_LEN - hlen;
951 
952         /*
953          * Take off the size of extension header itself (2 bytes for type and
954          * 2 bytes for length bytes), but ensure that the extension is at least
955          * 1 byte long so as not to have an empty extension last (WebSphere 7.x,
956          * 8.x are intolerant of that condition)
957          */
958         if (hlen > 4)
959             hlen -= 4;
960         else
961             hlen = 1;
962 
963         if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_padding)
964                 || !WPACKET_sub_allocate_bytes_u16(pkt, hlen, &padbytes)) {
965             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
966             return EXT_RETURN_FAIL;
967         }
968         memset(padbytes, 0, hlen);
969     }
970 
971     return EXT_RETURN_SENT;
972 }
973 
974 /*
975  * Construct the pre_shared_key extension
976  */
977 EXT_RETURN tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context,
978                                   X509 *x, size_t chainidx)
979 {
980 #ifndef OPENSSL_NO_TLS1_3
981     uint32_t agesec, agems = 0;
982     size_t reshashsize = 0, pskhashsize = 0, binderoffset, msglen;
983     unsigned char *resbinder = NULL, *pskbinder = NULL, *msgstart = NULL;
984     const EVP_MD *handmd = NULL, *mdres = NULL, *mdpsk = NULL;
985     int dores = 0;
986 
987     s->ext.tick_identity = 0;
988 
989     /*
990      * Note: At this stage of the code we only support adding a single
991      * resumption PSK. If we add support for multiple PSKs then the length
992      * calculations in the padding extension will need to be adjusted.
993      */
994 
995     /*
996      * If this is an incompatible or new session then we have nothing to resume
997      * so don't add this extension.
998      */
999     if (s->session->ssl_version != TLS1_3_VERSION
1000             || (s->session->ext.ticklen == 0 && s->psksession == NULL))
1001         return EXT_RETURN_NOT_SENT;
1002 
1003     if (s->hello_retry_request == SSL_HRR_PENDING)
1004         handmd = ssl_handshake_md(s);
1005 
1006     if (s->session->ext.ticklen != 0) {
1007         /* Get the digest associated with the ciphersuite in the session */
1008         if (s->session->cipher == NULL) {
1009             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1010             return EXT_RETURN_FAIL;
1011         }
1012         mdres = ssl_md(s->ctx, s->session->cipher->algorithm2);
1013         if (mdres == NULL) {
1014             /*
1015              * Don't recognize this cipher so we can't use the session.
1016              * Ignore it
1017              */
1018             goto dopsksess;
1019         }
1020 
1021         if (s->hello_retry_request == SSL_HRR_PENDING && mdres != handmd) {
1022             /*
1023              * Selected ciphersuite hash does not match the hash for the session
1024              * so we can't use it.
1025              */
1026             goto dopsksess;
1027         }
1028 
1029         /*
1030          * Technically the C standard just says time() returns a time_t and says
1031          * nothing about the encoding of that type. In practice most
1032          * implementations follow POSIX which holds it as an integral type in
1033          * seconds since epoch. We've already made the assumption that we can do
1034          * this in multiple places in the code, so portability shouldn't be an
1035          * issue.
1036          */
1037         agesec = (uint32_t)(time(NULL) - s->session->time);
1038         /*
1039          * We calculate the age in seconds but the server may work in ms. Due to
1040          * rounding errors we could overestimate the age by up to 1s. It is
1041          * better to underestimate it. Otherwise, if the RTT is very short, when
1042          * the server calculates the age reported by the client it could be
1043          * bigger than the age calculated on the server - which should never
1044          * happen.
1045          */
1046         if (agesec > 0)
1047             agesec--;
1048 
1049         if (s->session->ext.tick_lifetime_hint < agesec) {
1050             /* Ticket is too old. Ignore it. */
1051             goto dopsksess;
1052         }
1053 
1054         /*
1055          * Calculate age in ms. We're just doing it to nearest second. Should be
1056          * good enough.
1057          */
1058         agems = agesec * (uint32_t)1000;
1059 
1060         if (agesec != 0 && agems / (uint32_t)1000 != agesec) {
1061             /*
1062              * Overflow. Shouldn't happen unless this is a *really* old session.
1063              * If so we just ignore it.
1064              */
1065             goto dopsksess;
1066         }
1067 
1068         /*
1069          * Obfuscate the age. Overflow here is fine, this addition is supposed
1070          * to be mod 2^32.
1071          */
1072         agems += s->session->ext.tick_age_add;
1073 
1074         reshashsize = EVP_MD_get_size(mdres);
1075         s->ext.tick_identity++;
1076         dores = 1;
1077     }
1078 
1079  dopsksess:
1080     if (!dores && s->psksession == NULL)
1081         return EXT_RETURN_NOT_SENT;
1082 
1083     if (s->psksession != NULL) {
1084         mdpsk = ssl_md(s->ctx, s->psksession->cipher->algorithm2);
1085         if (mdpsk == NULL) {
1086             /*
1087              * Don't recognize this cipher so we can't use the session.
1088              * If this happens it's an application bug.
1089              */
1090             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_PSK);
1091             return EXT_RETURN_FAIL;
1092         }
1093 
1094         if (s->hello_retry_request == SSL_HRR_PENDING && mdpsk != handmd) {
1095             /*
1096              * Selected ciphersuite hash does not match the hash for the PSK
1097              * session. This is an application bug.
1098              */
1099             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_BAD_PSK);
1100             return EXT_RETURN_FAIL;
1101         }
1102 
1103         pskhashsize = EVP_MD_get_size(mdpsk);
1104     }
1105 
1106     /* Create the extension, but skip over the binder for now */
1107     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
1108             || !WPACKET_start_sub_packet_u16(pkt)
1109             || !WPACKET_start_sub_packet_u16(pkt)) {
1110         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1111         return EXT_RETURN_FAIL;
1112     }
1113 
1114     if (dores) {
1115         if (!WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick,
1116                                            s->session->ext.ticklen)
1117                 || !WPACKET_put_bytes_u32(pkt, agems)) {
1118             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1119             return EXT_RETURN_FAIL;
1120         }
1121     }
1122 
1123     if (s->psksession != NULL) {
1124         if (!WPACKET_sub_memcpy_u16(pkt, s->psksession_id,
1125                                     s->psksession_id_len)
1126                 || !WPACKET_put_bytes_u32(pkt, 0)) {
1127             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1128             return EXT_RETURN_FAIL;
1129         }
1130         s->ext.tick_identity++;
1131     }
1132 
1133     if (!WPACKET_close(pkt)
1134             || !WPACKET_get_total_written(pkt, &binderoffset)
1135             || !WPACKET_start_sub_packet_u16(pkt)
1136             || (dores
1137                 && !WPACKET_sub_allocate_bytes_u8(pkt, reshashsize, &resbinder))
1138             || (s->psksession != NULL
1139                 && !WPACKET_sub_allocate_bytes_u8(pkt, pskhashsize, &pskbinder))
1140             || !WPACKET_close(pkt)
1141             || !WPACKET_close(pkt)
1142             || !WPACKET_get_total_written(pkt, &msglen)
1143                /*
1144                 * We need to fill in all the sub-packet lengths now so we can
1145                 * calculate the HMAC of the message up to the binders
1146                 */
1147             || !WPACKET_fill_lengths(pkt)) {
1148         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1149         return EXT_RETURN_FAIL;
1150     }
1151 
1152     msgstart = WPACKET_get_curr(pkt) - msglen;
1153 
1154     if (dores
1155             && tls_psk_do_binder(s, mdres, msgstart, binderoffset, NULL,
1156                                  resbinder, s->session, 1, 0) != 1) {
1157         /* SSLfatal() already called */
1158         return EXT_RETURN_FAIL;
1159     }
1160 
1161     if (s->psksession != NULL
1162             && tls_psk_do_binder(s, mdpsk, msgstart, binderoffset, NULL,
1163                                  pskbinder, s->psksession, 1, 1) != 1) {
1164         /* SSLfatal() already called */
1165         return EXT_RETURN_FAIL;
1166     }
1167 
1168     return EXT_RETURN_SENT;
1169 #else
1170     return EXT_RETURN_NOT_SENT;
1171 #endif
1172 }
1173 
1174 EXT_RETURN tls_construct_ctos_post_handshake_auth(SSL *s, WPACKET *pkt,
1175                                                   ossl_unused unsigned int context,
1176                                                   ossl_unused X509 *x,
1177                                                   ossl_unused size_t chainidx)
1178 {
1179 #ifndef OPENSSL_NO_TLS1_3
1180     if (!s->pha_enabled)
1181         return EXT_RETURN_NOT_SENT;
1182 
1183     /* construct extension - 0 length, no contents */
1184     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_post_handshake_auth)
1185             || !WPACKET_start_sub_packet_u16(pkt)
1186             || !WPACKET_close(pkt)) {
1187         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1188         return EXT_RETURN_FAIL;
1189     }
1190 
1191     s->post_handshake_auth = SSL_PHA_EXT_SENT;
1192 
1193     return EXT_RETURN_SENT;
1194 #else
1195     return EXT_RETURN_NOT_SENT;
1196 #endif
1197 }
1198 
1199 
1200 /*
1201  * Parse the server's renegotiation binding and abort if it's not right
1202  */
1203 int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
1204                                X509 *x, size_t chainidx)
1205 {
1206     size_t expected_len = s->s3.previous_client_finished_len
1207         + s->s3.previous_server_finished_len;
1208     size_t ilen;
1209     const unsigned char *data;
1210 
1211     /* Check for logic errors */
1212     if (!ossl_assert(expected_len == 0
1213                      || s->s3.previous_client_finished_len != 0)
1214         || !ossl_assert(expected_len == 0
1215                         || s->s3.previous_server_finished_len != 0)) {
1216         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1217         return 0;
1218     }
1219 
1220     /* Parse the length byte */
1221     if (!PACKET_get_1_len(pkt, &ilen)) {
1222         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_RENEGOTIATION_ENCODING_ERR);
1223         return 0;
1224     }
1225 
1226     /* Consistency check */
1227     if (PACKET_remaining(pkt) != ilen) {
1228         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_RENEGOTIATION_ENCODING_ERR);
1229         return 0;
1230     }
1231 
1232     /* Check that the extension matches */
1233     if (ilen != expected_len) {
1234         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_RENEGOTIATION_MISMATCH);
1235         return 0;
1236     }
1237 
1238     if (!PACKET_get_bytes(pkt, &data, s->s3.previous_client_finished_len)
1239         || memcmp(data, s->s3.previous_client_finished,
1240                   s->s3.previous_client_finished_len) != 0) {
1241         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_RENEGOTIATION_MISMATCH);
1242         return 0;
1243     }
1244 
1245     if (!PACKET_get_bytes(pkt, &data, s->s3.previous_server_finished_len)
1246         || memcmp(data, s->s3.previous_server_finished,
1247                   s->s3.previous_server_finished_len) != 0) {
1248         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_RENEGOTIATION_MISMATCH);
1249         return 0;
1250     }
1251     s->s3.send_connection_binding = 1;
1252 
1253     return 1;
1254 }
1255 
1256 /* Parse the server's max fragment len extension packet */
1257 int tls_parse_stoc_maxfragmentlen(SSL *s, PACKET *pkt, unsigned int context,
1258                                   X509 *x, size_t chainidx)
1259 {
1260     unsigned int value;
1261 
1262     if (PACKET_remaining(pkt) != 1 || !PACKET_get_1(pkt, &value)) {
1263         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1264         return 0;
1265     }
1266 
1267     /* |value| should contains a valid max-fragment-length code. */
1268     if (!IS_MAX_FRAGMENT_LENGTH_EXT_VALID(value)) {
1269         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1270                  SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
1271         return 0;
1272     }
1273 
1274     /* Must be the same value as client-configured one who was sent to server */
1275     /*-
1276      * RFC 6066: if a client receives a maximum fragment length negotiation
1277      * response that differs from the length it requested, ...
1278      * It must abort with SSL_AD_ILLEGAL_PARAMETER alert
1279      */
1280     if (value != s->ext.max_fragment_len_mode) {
1281         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1282                  SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
1283         return 0;
1284     }
1285 
1286     /*
1287      * Maximum Fragment Length Negotiation succeeded.
1288      * The negotiated Maximum Fragment Length is binding now.
1289      */
1290     s->session->ext.max_fragment_len_mode = value;
1291 
1292     return 1;
1293 }
1294 
1295 int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, unsigned int context,
1296                                X509 *x, size_t chainidx)
1297 {
1298     if (s->ext.hostname == NULL) {
1299         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1300         return 0;
1301     }
1302 
1303     if (PACKET_remaining(pkt) > 0) {
1304         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1305         return 0;
1306     }
1307 
1308     if (!s->hit) {
1309         if (s->session->ext.hostname != NULL) {
1310             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1311             return 0;
1312         }
1313         s->session->ext.hostname = OPENSSL_strdup(s->ext.hostname);
1314         if (s->session->ext.hostname == NULL) {
1315             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1316             return 0;
1317         }
1318     }
1319 
1320     return 1;
1321 }
1322 
1323 int tls_parse_stoc_ec_pt_formats(SSL *s, PACKET *pkt, unsigned int context,
1324                                  X509 *x, size_t chainidx)
1325 {
1326     size_t ecpointformats_len;
1327     PACKET ecptformatlist;
1328 
1329     if (!PACKET_as_length_prefixed_1(pkt, &ecptformatlist)) {
1330         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1331         return 0;
1332     }
1333     if (!s->hit) {
1334         ecpointformats_len = PACKET_remaining(&ecptformatlist);
1335         if (ecpointformats_len == 0) {
1336             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_LENGTH);
1337             return 0;
1338         }
1339 
1340         s->ext.peer_ecpointformats_len = 0;
1341         OPENSSL_free(s->ext.peer_ecpointformats);
1342         s->ext.peer_ecpointformats = OPENSSL_malloc(ecpointformats_len);
1343         if (s->ext.peer_ecpointformats == NULL) {
1344             s->ext.peer_ecpointformats_len = 0;
1345             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1346             return 0;
1347         }
1348 
1349         s->ext.peer_ecpointformats_len = ecpointformats_len;
1350 
1351         if (!PACKET_copy_bytes(&ecptformatlist,
1352                                s->ext.peer_ecpointformats,
1353                                ecpointformats_len)) {
1354             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1355             return 0;
1356         }
1357     }
1358 
1359     return 1;
1360 }
1361 
1362 int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
1363                                   X509 *x, size_t chainidx)
1364 {
1365     if (s->ext.session_ticket_cb != NULL &&
1366         !s->ext.session_ticket_cb(s, PACKET_data(pkt),
1367                               PACKET_remaining(pkt),
1368                               s->ext.session_ticket_cb_arg)) {
1369         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_BAD_EXTENSION);
1370         return 0;
1371     }
1372 
1373     if (!tls_use_ticket(s)) {
1374         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
1375         return 0;
1376     }
1377     if (PACKET_remaining(pkt) > 0) {
1378         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1379         return 0;
1380     }
1381 
1382     s->ext.ticket_expected = 1;
1383 
1384     return 1;
1385 }
1386 
1387 #ifndef OPENSSL_NO_OCSP
1388 int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, unsigned int context,
1389                                   X509 *x, size_t chainidx)
1390 {
1391     if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST) {
1392         /* We ignore this if the server sends a CertificateRequest */
1393         return 1;
1394     }
1395 
1396     /*
1397      * MUST only be sent if we've requested a status
1398      * request message. In TLS <= 1.2 it must also be empty.
1399      */
1400     if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp) {
1401         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
1402         return 0;
1403     }
1404     if (!SSL_IS_TLS13(s) && PACKET_remaining(pkt) > 0) {
1405         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1406         return 0;
1407     }
1408 
1409     if (SSL_IS_TLS13(s)) {
1410         /* We only know how to handle this if it's for the first Certificate in
1411          * the chain. We ignore any other responses.
1412          */
1413         if (chainidx != 0)
1414             return 1;
1415 
1416         /* SSLfatal() already called */
1417         return tls_process_cert_status_body(s, pkt);
1418     }
1419 
1420     /* Set flag to expect CertificateStatus message */
1421     s->ext.status_expected = 1;
1422 
1423     return 1;
1424 }
1425 #endif
1426 
1427 
1428 #ifndef OPENSSL_NO_CT
1429 int tls_parse_stoc_sct(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1430                        size_t chainidx)
1431 {
1432     if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST) {
1433         /* We ignore this if the server sends it in a CertificateRequest */
1434         return 1;
1435     }
1436 
1437     /*
1438      * Only take it if we asked for it - i.e if there is no CT validation
1439      * callback set, then a custom extension MAY be processing it, so we
1440      * need to let control continue to flow to that.
1441      */
1442     if (s->ct_validation_callback != NULL) {
1443         size_t size = PACKET_remaining(pkt);
1444 
1445         /* Simply copy it off for later processing */
1446         OPENSSL_free(s->ext.scts);
1447         s->ext.scts = NULL;
1448 
1449         s->ext.scts_len = (uint16_t)size;
1450         if (size > 0) {
1451             s->ext.scts = OPENSSL_malloc(size);
1452             if (s->ext.scts == NULL) {
1453                 s->ext.scts_len = 0;
1454                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
1455                 return 0;
1456             }
1457             if (!PACKET_copy_bytes(pkt, s->ext.scts, size)) {
1458                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1459                 return 0;
1460             }
1461         }
1462     } else {
1463         ENDPOINT role = (context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0
1464                         ? ENDPOINT_CLIENT : ENDPOINT_BOTH;
1465 
1466         /*
1467          * If we didn't ask for it then there must be a custom extension,
1468          * otherwise this is unsolicited.
1469          */
1470         if (custom_ext_find(&s->cert->custext, role,
1471                             TLSEXT_TYPE_signed_certificate_timestamp,
1472                             NULL) == NULL) {
1473             SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
1474             return 0;
1475         }
1476 
1477         if (!custom_ext_parse(s, context,
1478                              TLSEXT_TYPE_signed_certificate_timestamp,
1479                              PACKET_data(pkt), PACKET_remaining(pkt),
1480                              x, chainidx)) {
1481             /* SSLfatal already called */
1482             return 0;
1483         }
1484     }
1485 
1486     return 1;
1487 }
1488 #endif
1489 
1490 
1491 #ifndef OPENSSL_NO_NEXTPROTONEG
1492 /*
1493  * ssl_next_proto_validate validates a Next Protocol Negotiation block. No
1494  * elements of zero length are allowed and the set of elements must exactly
1495  * fill the length of the block. Returns 1 on success or 0 on failure.
1496  */
1497 static int ssl_next_proto_validate(SSL *s, PACKET *pkt)
1498 {
1499     PACKET tmp_protocol;
1500 
1501     while (PACKET_remaining(pkt)) {
1502         if (!PACKET_get_length_prefixed_1(pkt, &tmp_protocol)
1503             || PACKET_remaining(&tmp_protocol) == 0) {
1504             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1505             return 0;
1506         }
1507     }
1508 
1509     return 1;
1510 }
1511 
1512 int tls_parse_stoc_npn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1513                        size_t chainidx)
1514 {
1515     unsigned char *selected;
1516     unsigned char selected_len;
1517     PACKET tmppkt;
1518 
1519     /* Check if we are in a renegotiation. If so ignore this extension */
1520     if (!SSL_IS_FIRST_HANDSHAKE(s))
1521         return 1;
1522 
1523     /* We must have requested it. */
1524     if (s->ctx->ext.npn_select_cb == NULL) {
1525         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
1526         return 0;
1527     }
1528 
1529     /* The data must be valid */
1530     tmppkt = *pkt;
1531     if (!ssl_next_proto_validate(s, &tmppkt)) {
1532         /* SSLfatal() already called */
1533         return 0;
1534     }
1535     if (s->ctx->ext.npn_select_cb(s, &selected, &selected_len,
1536                                   PACKET_data(pkt),
1537                                   PACKET_remaining(pkt),
1538                                   s->ctx->ext.npn_select_cb_arg) !=
1539              SSL_TLSEXT_ERR_OK) {
1540         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_BAD_EXTENSION);
1541         return 0;
1542     }
1543 
1544     /*
1545      * Could be non-NULL if server has sent multiple NPN extensions in
1546      * a single Serverhello
1547      */
1548     OPENSSL_free(s->ext.npn);
1549     s->ext.npn = OPENSSL_malloc(selected_len);
1550     if (s->ext.npn == NULL) {
1551         s->ext.npn_len = 0;
1552         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1553         return 0;
1554     }
1555 
1556     memcpy(s->ext.npn, selected, selected_len);
1557     s->ext.npn_len = selected_len;
1558     s->s3.npn_seen = 1;
1559 
1560     return 1;
1561 }
1562 #endif
1563 
1564 int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1565                         size_t chainidx)
1566 {
1567     size_t len;
1568 
1569     /* We must have requested it. */
1570     if (!s->s3.alpn_sent) {
1571         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
1572         return 0;
1573     }
1574     /*-
1575      * The extension data consists of:
1576      *   uint16 list_length
1577      *   uint8 proto_length;
1578      *   uint8 proto[proto_length];
1579      */
1580     if (!PACKET_get_net_2_len(pkt, &len)
1581         || PACKET_remaining(pkt) != len || !PACKET_get_1_len(pkt, &len)
1582         || PACKET_remaining(pkt) != len) {
1583         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1584         return 0;
1585     }
1586     OPENSSL_free(s->s3.alpn_selected);
1587     s->s3.alpn_selected = OPENSSL_malloc(len);
1588     if (s->s3.alpn_selected == NULL) {
1589         s->s3.alpn_selected_len = 0;
1590         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1591         return 0;
1592     }
1593     if (!PACKET_copy_bytes(pkt, s->s3.alpn_selected, len)) {
1594         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1595         return 0;
1596     }
1597     s->s3.alpn_selected_len = len;
1598 
1599     if (s->session->ext.alpn_selected == NULL
1600             || s->session->ext.alpn_selected_len != len
1601             || memcmp(s->session->ext.alpn_selected, s->s3.alpn_selected, len)
1602                != 0) {
1603         /* ALPN not consistent with the old session so cannot use early_data */
1604         s->ext.early_data_ok = 0;
1605     }
1606     if (!s->hit) {
1607         /*
1608          * This is a new session and so alpn_selected should have been
1609          * initialised to NULL. We should update it with the selected ALPN.
1610          */
1611         if (!ossl_assert(s->session->ext.alpn_selected == NULL)) {
1612             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1613             return 0;
1614         }
1615         s->session->ext.alpn_selected =
1616             OPENSSL_memdup(s->s3.alpn_selected, s->s3.alpn_selected_len);
1617         if (s->session->ext.alpn_selected == NULL) {
1618             s->session->ext.alpn_selected_len = 0;
1619             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1620             return 0;
1621         }
1622         s->session->ext.alpn_selected_len = s->s3.alpn_selected_len;
1623     }
1624 
1625     return 1;
1626 }
1627 
1628 #ifndef OPENSSL_NO_SRTP
1629 int tls_parse_stoc_use_srtp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1630                             size_t chainidx)
1631 {
1632     unsigned int id, ct, mki;
1633     int i;
1634     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
1635     SRTP_PROTECTION_PROFILE *prof;
1636 
1637     if (!PACKET_get_net_2(pkt, &ct) || ct != 2
1638             || !PACKET_get_net_2(pkt, &id)
1639             || !PACKET_get_1(pkt, &mki)
1640             || PACKET_remaining(pkt) != 0) {
1641         SSLfatal(s, SSL_AD_DECODE_ERROR,
1642                  SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
1643         return 0;
1644     }
1645 
1646     if (mki != 0) {
1647         /* Must be no MKI, since we never offer one */
1648         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_SRTP_MKI_VALUE);
1649         return 0;
1650     }
1651 
1652     /* Throw an error if the server gave us an unsolicited extension */
1653     clnt = SSL_get_srtp_profiles(s);
1654     if (clnt == NULL) {
1655         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_NO_SRTP_PROFILES);
1656         return 0;
1657     }
1658 
1659     /*
1660      * Check to see if the server gave us something we support (and
1661      * presumably offered)
1662      */
1663     for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) {
1664         prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
1665 
1666         if (prof->id == id) {
1667             s->srtp_profile = prof;
1668             return 1;
1669         }
1670     }
1671 
1672     SSLfatal(s, SSL_AD_DECODE_ERROR,
1673              SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
1674     return 0;
1675 }
1676 #endif
1677 
1678 int tls_parse_stoc_etm(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1679                        size_t chainidx)
1680 {
1681     /* Ignore if inappropriate ciphersuite */
1682     if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
1683             && s->s3.tmp.new_cipher->algorithm_mac != SSL_AEAD
1684             && s->s3.tmp.new_cipher->algorithm_enc != SSL_RC4
1685             && s->s3.tmp.new_cipher->algorithm_enc != SSL_eGOST2814789CNT
1686             && s->s3.tmp.new_cipher->algorithm_enc != SSL_eGOST2814789CNT12
1687             && s->s3.tmp.new_cipher->algorithm_enc != SSL_MAGMA
1688             && s->s3.tmp.new_cipher->algorithm_enc != SSL_KUZNYECHIK)
1689         s->ext.use_etm = 1;
1690 
1691     return 1;
1692 }
1693 
1694 int tls_parse_stoc_ems(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1695                        size_t chainidx)
1696 {
1697     if (s->options & SSL_OP_NO_EXTENDED_MASTER_SECRET)
1698         return 1;
1699     s->s3.flags |= TLS1_FLAGS_RECEIVED_EXTMS;
1700     if (!s->hit)
1701         s->session->flags |= SSL_SESS_FLAG_EXTMS;
1702 
1703     return 1;
1704 }
1705 
1706 int tls_parse_stoc_supported_versions(SSL *s, PACKET *pkt, unsigned int context,
1707                                       X509 *x, size_t chainidx)
1708 {
1709     unsigned int version;
1710 
1711     if (!PACKET_get_net_2(pkt, &version)
1712             || PACKET_remaining(pkt) != 0) {
1713         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_MISMATCH);
1714         return 0;
1715     }
1716 
1717     /*
1718      * The only protocol version we support which is valid in this extension in
1719      * a ServerHello is TLSv1.3 therefore we shouldn't be getting anything else.
1720      */
1721     if (version != TLS1_3_VERSION) {
1722         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1723                  SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
1724         return 0;
1725     }
1726 
1727     /* We ignore this extension for HRRs except to sanity check it */
1728     if (context == SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)
1729         return 1;
1730 
1731     /* We just set it here. We validate it in ssl_choose_client_version */
1732     s->version = version;
1733 
1734     return 1;
1735 }
1736 
1737 int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1738                              size_t chainidx)
1739 {
1740 #ifndef OPENSSL_NO_TLS1_3
1741     unsigned int group_id;
1742     PACKET encoded_pt;
1743     EVP_PKEY *ckey = s->s3.tmp.pkey, *skey = NULL;
1744     const TLS_GROUP_INFO *ginf = NULL;
1745 
1746     /* Sanity check */
1747     if (ckey == NULL || s->s3.peer_tmp != NULL) {
1748         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1749         return 0;
1750     }
1751 
1752     if (!PACKET_get_net_2(pkt, &group_id)) {
1753         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_MISMATCH);
1754         return 0;
1755     }
1756 
1757     if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0) {
1758         const uint16_t *pgroups = NULL;
1759         size_t i, num_groups;
1760 
1761         if (PACKET_remaining(pkt) != 0) {
1762             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_MISMATCH);
1763             return 0;
1764         }
1765 
1766         /*
1767          * It is an error if the HelloRetryRequest wants a key_share that we
1768          * already sent in the first ClientHello
1769          */
1770         if (group_id == s->s3.group_id) {
1771             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_KEY_SHARE);
1772             return 0;
1773         }
1774 
1775         /* Validate the selected group is one we support */
1776         tls1_get_supported_groups(s, &pgroups, &num_groups);
1777         for (i = 0; i < num_groups; i++) {
1778             if (group_id == pgroups[i])
1779                 break;
1780         }
1781         if (i >= num_groups
1782                 || !tls_group_allowed(s, group_id, SSL_SECOP_CURVE_SUPPORTED)
1783                 || !tls_valid_group(s, group_id, TLS1_3_VERSION, TLS1_3_VERSION,
1784                                     0, NULL)) {
1785             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_KEY_SHARE);
1786             return 0;
1787         }
1788 
1789         s->s3.group_id = group_id;
1790         EVP_PKEY_free(s->s3.tmp.pkey);
1791         s->s3.tmp.pkey = NULL;
1792         return 1;
1793     }
1794 
1795     if (group_id != s->s3.group_id) {
1796         /*
1797          * This isn't for the group that we sent in the original
1798          * key_share!
1799          */
1800         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_KEY_SHARE);
1801         return 0;
1802     }
1803     /* Retain this group in the SSL_SESSION */
1804     if (!s->hit) {
1805         s->session->kex_group = group_id;
1806     } else if (group_id != s->session->kex_group) {
1807         /*
1808          * If this is a resumption but changed what group was used, we need
1809          * to record the new group in the session, but the session is not
1810          * a new session and could be in use by other threads.  So, make
1811          * a copy of the session to record the new information so that it's
1812          * useful for any sessions resumed from tickets issued on this
1813          * connection.
1814          */
1815         SSL_SESSION *new_sess;
1816 
1817         if ((new_sess = ssl_session_dup(s->session, 0)) == NULL) {
1818             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
1819             return 0;
1820         }
1821         SSL_SESSION_free(s->session);
1822         s->session = new_sess;
1823         s->session->kex_group = group_id;
1824     }
1825 
1826     if ((ginf = tls1_group_id_lookup(s->ctx, group_id)) == NULL) {
1827         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_KEY_SHARE);
1828         return 0;
1829     }
1830 
1831     if (!PACKET_as_length_prefixed_2(pkt, &encoded_pt)
1832             || PACKET_remaining(&encoded_pt) == 0) {
1833         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_MISMATCH);
1834         return 0;
1835     }
1836 
1837     if (!ginf->is_kem) {
1838         /* Regular KEX */
1839         skey = EVP_PKEY_new();
1840         if (skey == NULL || EVP_PKEY_copy_parameters(skey, ckey) <= 0) {
1841             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_COPY_PARAMETERS_FAILED);
1842             EVP_PKEY_free(skey);
1843             return 0;
1844         }
1845 
1846         if (tls13_set_encoded_pub_key(skey, PACKET_data(&encoded_pt),
1847                                       PACKET_remaining(&encoded_pt)) <= 0) {
1848             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_ECPOINT);
1849             EVP_PKEY_free(skey);
1850             return 0;
1851         }
1852 
1853         if (ssl_derive(s, ckey, skey, 1) == 0) {
1854             /* SSLfatal() already called */
1855             EVP_PKEY_free(skey);
1856             return 0;
1857         }
1858         s->s3.peer_tmp = skey;
1859     } else {
1860         /* KEM Mode */
1861         const unsigned char *ct = PACKET_data(&encoded_pt);
1862         size_t ctlen = PACKET_remaining(&encoded_pt);
1863 
1864         if (ssl_decapsulate(s, ckey, ct, ctlen, 1) == 0) {
1865             /* SSLfatal() already called */
1866             return 0;
1867         }
1868     }
1869     s->s3.did_kex = 1;
1870 #endif
1871 
1872     return 1;
1873 }
1874 
1875 int tls_parse_stoc_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1876                        size_t chainidx)
1877 {
1878     PACKET cookie;
1879 
1880     if (!PACKET_as_length_prefixed_2(pkt, &cookie)
1881             || !PACKET_memdup(&cookie, &s->ext.tls13_cookie,
1882                               &s->ext.tls13_cookie_len)) {
1883         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_MISMATCH);
1884         return 0;
1885     }
1886 
1887     return 1;
1888 }
1889 
1890 int tls_parse_stoc_early_data(SSL *s, PACKET *pkt, unsigned int context,
1891                               X509 *x, size_t chainidx)
1892 {
1893     if (context == SSL_EXT_TLS1_3_NEW_SESSION_TICKET) {
1894         unsigned long max_early_data;
1895 
1896         if (!PACKET_get_net_4(pkt, &max_early_data)
1897                 || PACKET_remaining(pkt) != 0) {
1898             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_INVALID_MAX_EARLY_DATA);
1899             return 0;
1900         }
1901 
1902         s->session->ext.max_early_data = max_early_data;
1903 
1904         return 1;
1905     }
1906 
1907     if (PACKET_remaining(pkt) != 0) {
1908         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_BAD_EXTENSION);
1909         return 0;
1910     }
1911 
1912     if (!s->ext.early_data_ok
1913             || !s->hit) {
1914         /*
1915          * If we get here then we didn't send early data, or we didn't resume
1916          * using the first identity, or the SNI/ALPN is not consistent so the
1917          * server should not be accepting it.
1918          */
1919         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_EXTENSION);
1920         return 0;
1921     }
1922 
1923     s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1924 
1925     return 1;
1926 }
1927 
1928 int tls_parse_stoc_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1929                        size_t chainidx)
1930 {
1931 #ifndef OPENSSL_NO_TLS1_3
1932     unsigned int identity;
1933 
1934     if (!PACKET_get_net_2(pkt, &identity) || PACKET_remaining(pkt) != 0) {
1935         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_R_LENGTH_MISMATCH);
1936         return 0;
1937     }
1938 
1939     if (identity >= (unsigned int)s->ext.tick_identity) {
1940         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_PSK_IDENTITY);
1941         return 0;
1942     }
1943 
1944     /*
1945      * Session resumption tickets are always sent before PSK tickets. If the
1946      * ticket index is 0 then it must be for a session resumption ticket if we
1947      * sent two tickets, or if we didn't send a PSK ticket.
1948      */
1949     if (identity == 0 && (s->psksession == NULL || s->ext.tick_identity == 2)) {
1950         s->hit = 1;
1951         SSL_SESSION_free(s->psksession);
1952         s->psksession = NULL;
1953         return 1;
1954     }
1955 
1956     if (s->psksession == NULL) {
1957         /* Should never happen */
1958         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
1959         return 0;
1960     }
1961 
1962     /*
1963      * If we used the external PSK for sending early_data then s->early_secret
1964      * is already set up, so don't overwrite it. Otherwise we copy the
1965      * early_secret across that we generated earlier.
1966      */
1967     if ((s->early_data_state != SSL_EARLY_DATA_WRITE_RETRY
1968                 && s->early_data_state != SSL_EARLY_DATA_FINISHED_WRITING)
1969             || s->session->ext.max_early_data > 0
1970             || s->psksession->ext.max_early_data == 0)
1971         memcpy(s->early_secret, s->psksession->early_secret, EVP_MAX_MD_SIZE);
1972 
1973     SSL_SESSION_free(s->session);
1974     s->session = s->psksession;
1975     s->psksession = NULL;
1976     s->hit = 1;
1977     /* Early data is only allowed if we used the first ticket */
1978     if (identity != 0)
1979         s->ext.early_data_ok = 0;
1980 #endif
1981 
1982     return 1;
1983 }
1984