xref: /freebsd/crypto/openssl/ssl/statem/extensions_clnt.c (revision 833a452e9f082a7982a31c21f0da437dbbe0a39d)
1 /*
2  * Copyright 2016-2021 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_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, 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             s->psksession_id_len = 0;
820             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
821                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
822             return EXT_RETURN_FAIL;
823         }
824         s->psksession_id_len = idlen;
825     }
826 
827     if (s->early_data_state != SSL_EARLY_DATA_CONNECTING
828             || (s->session->ext.max_early_data == 0
829                 && (psksess == NULL || psksess->ext.max_early_data == 0))) {
830         s->max_early_data = 0;
831         return EXT_RETURN_NOT_SENT;
832     }
833     edsess = s->session->ext.max_early_data != 0 ? s->session : psksess;
834     s->max_early_data = edsess->ext.max_early_data;
835 
836     if (edsess->ext.hostname != NULL) {
837         if (s->ext.hostname == NULL
838                 || (s->ext.hostname != NULL
839                     && strcmp(s->ext.hostname, edsess->ext.hostname) != 0)) {
840             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
841                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
842                      SSL_R_INCONSISTENT_EARLY_DATA_SNI);
843             return EXT_RETURN_FAIL;
844         }
845     }
846 
847     if ((s->ext.alpn == NULL && edsess->ext.alpn_selected != NULL)) {
848         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
849                  SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
850         return EXT_RETURN_FAIL;
851     }
852 
853     /*
854      * Verify that we are offering an ALPN protocol consistent with the early
855      * data.
856      */
857     if (edsess->ext.alpn_selected != NULL) {
858         PACKET prots, alpnpkt;
859         int found = 0;
860 
861         if (!PACKET_buf_init(&prots, s->ext.alpn, s->ext.alpn_len)) {
862             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
863                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
864             return EXT_RETURN_FAIL;
865         }
866         while (PACKET_get_length_prefixed_1(&prots, &alpnpkt)) {
867             if (PACKET_equal(&alpnpkt, edsess->ext.alpn_selected,
868                              edsess->ext.alpn_selected_len)) {
869                 found = 1;
870                 break;
871             }
872         }
873         if (!found) {
874             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
875                      SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
876                      SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
877             return EXT_RETURN_FAIL;
878         }
879     }
880 
881     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
882             || !WPACKET_start_sub_packet_u16(pkt)
883             || !WPACKET_close(pkt)) {
884         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
885                  ERR_R_INTERNAL_ERROR);
886         return EXT_RETURN_FAIL;
887     }
888 
889     /*
890      * We set this to rejected here. Later, if the server acknowledges the
891      * extension, we set it to accepted.
892      */
893     s->ext.early_data = SSL_EARLY_DATA_REJECTED;
894     s->ext.early_data_ok = 1;
895 
896     return EXT_RETURN_SENT;
897 }
898 
899 #define F5_WORKAROUND_MIN_MSG_LEN   0xff
900 #define F5_WORKAROUND_MAX_MSG_LEN   0x200
901 
902 /*
903  * PSK pre binder overhead =
904  *  2 bytes for TLSEXT_TYPE_psk
905  *  2 bytes for extension length
906  *  2 bytes for identities list length
907  *  2 bytes for identity length
908  *  4 bytes for obfuscated_ticket_age
909  *  2 bytes for binder list length
910  *  1 byte for binder length
911  * The above excludes the number of bytes for the identity itself and the
912  * subsequent binder bytes
913  */
914 #define PSK_PRE_BINDER_OVERHEAD (2 + 2 + 2 + 2 + 4 + 2 + 1)
915 
916 EXT_RETURN tls_construct_ctos_padding(SSL *s, WPACKET *pkt,
917                                       unsigned int context, X509 *x,
918                                       size_t chainidx)
919 {
920     unsigned char *padbytes;
921     size_t hlen;
922 
923     if ((s->options & SSL_OP_TLSEXT_PADDING) == 0)
924         return EXT_RETURN_NOT_SENT;
925 
926     /*
927      * Add padding to workaround bugs in F5 terminators. See RFC7685.
928      * This code calculates the length of all extensions added so far but
929      * excludes the PSK extension (because that MUST be written last). Therefore
930      * this extension MUST always appear second to last.
931      */
932     if (!WPACKET_get_total_written(pkt, &hlen)) {
933         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PADDING,
934                  ERR_R_INTERNAL_ERROR);
935         return EXT_RETURN_FAIL;
936     }
937 
938     /*
939      * If we're going to send a PSK then that will be written out after this
940      * extension, so we need to calculate how long it is going to be.
941      */
942     if (s->session->ssl_version == TLS1_3_VERSION
943             && s->session->ext.ticklen != 0
944             && s->session->cipher != NULL) {
945         const EVP_MD *md = ssl_md(s->session->cipher->algorithm2);
946 
947         if (md != NULL) {
948             /*
949              * Add the fixed PSK overhead, the identity length and the binder
950              * length.
951              */
952             hlen +=  PSK_PRE_BINDER_OVERHEAD + s->session->ext.ticklen
953                      + EVP_MD_size(md);
954         }
955     }
956 
957     if (hlen > F5_WORKAROUND_MIN_MSG_LEN && hlen < F5_WORKAROUND_MAX_MSG_LEN) {
958         /* Calculate the amount of padding we need to add */
959         hlen = F5_WORKAROUND_MAX_MSG_LEN - hlen;
960 
961         /*
962          * Take off the size of extension header itself (2 bytes for type and
963          * 2 bytes for length bytes), but ensure that the extension is at least
964          * 1 byte long so as not to have an empty extension last (WebSphere 7.x,
965          * 8.x are intolerant of that condition)
966          */
967         if (hlen > 4)
968             hlen -= 4;
969         else
970             hlen = 1;
971 
972         if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_padding)
973                 || !WPACKET_sub_allocate_bytes_u16(pkt, hlen, &padbytes)) {
974             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PADDING,
975                      ERR_R_INTERNAL_ERROR);
976             return EXT_RETURN_FAIL;
977         }
978         memset(padbytes, 0, hlen);
979     }
980 
981     return EXT_RETURN_SENT;
982 }
983 
984 /*
985  * Construct the pre_shared_key extension
986  */
987 EXT_RETURN tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context,
988                                   X509 *x, size_t chainidx)
989 {
990 #ifndef OPENSSL_NO_TLS1_3
991     uint32_t now, agesec, agems = 0;
992     size_t reshashsize = 0, pskhashsize = 0, binderoffset, msglen;
993     unsigned char *resbinder = NULL, *pskbinder = NULL, *msgstart = NULL;
994     const EVP_MD *handmd = NULL, *mdres = NULL, *mdpsk = NULL;
995     int dores = 0;
996 
997     s->ext.tick_identity = 0;
998 
999     /*
1000      * Note: At this stage of the code we only support adding a single
1001      * resumption PSK. If we add support for multiple PSKs then the length
1002      * calculations in the padding extension will need to be adjusted.
1003      */
1004 
1005     /*
1006      * If this is an incompatible or new session then we have nothing to resume
1007      * so don't add this extension.
1008      */
1009     if (s->session->ssl_version != TLS1_3_VERSION
1010             || (s->session->ext.ticklen == 0 && s->psksession == NULL))
1011         return EXT_RETURN_NOT_SENT;
1012 
1013     if (s->hello_retry_request == SSL_HRR_PENDING)
1014         handmd = ssl_handshake_md(s);
1015 
1016     if (s->session->ext.ticklen != 0) {
1017         /* Get the digest associated with the ciphersuite in the session */
1018         if (s->session->cipher == NULL) {
1019             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1020                      ERR_R_INTERNAL_ERROR);
1021             return EXT_RETURN_FAIL;
1022         }
1023         mdres = ssl_md(s->session->cipher->algorithm2);
1024         if (mdres == NULL) {
1025             /*
1026              * Don't recognize this cipher so we can't use the session.
1027              * Ignore it
1028              */
1029             goto dopsksess;
1030         }
1031 
1032         if (s->hello_retry_request == SSL_HRR_PENDING && mdres != handmd) {
1033             /*
1034              * Selected ciphersuite hash does not match the hash for the session
1035              * so we can't use it.
1036              */
1037             goto dopsksess;
1038         }
1039 
1040         /*
1041          * Technically the C standard just says time() returns a time_t and says
1042          * nothing about the encoding of that type. In practice most
1043          * implementations follow POSIX which holds it as an integral type in
1044          * seconds since epoch. We've already made the assumption that we can do
1045          * this in multiple places in the code, so portability shouldn't be an
1046          * issue.
1047          */
1048         now = (uint32_t)time(NULL);
1049         agesec = now - (uint32_t)s->session->time;
1050         /*
1051          * We calculate the age in seconds but the server may work in ms. Due to
1052          * rounding errors we could overestimate the age by up to 1s. It is
1053          * better to underestimate it. Otherwise, if the RTT is very short, when
1054          * the server calculates the age reported by the client it could be
1055          * bigger than the age calculated on the server - which should never
1056          * happen.
1057          */
1058         if (agesec > 0)
1059             agesec--;
1060 
1061         if (s->session->ext.tick_lifetime_hint < agesec) {
1062             /* Ticket is too old. Ignore it. */
1063             goto dopsksess;
1064         }
1065 
1066         /*
1067          * Calculate age in ms. We're just doing it to nearest second. Should be
1068          * good enough.
1069          */
1070         agems = agesec * (uint32_t)1000;
1071 
1072         if (agesec != 0 && agems / (uint32_t)1000 != agesec) {
1073             /*
1074              * Overflow. Shouldn't happen unless this is a *really* old session.
1075              * If so we just ignore it.
1076              */
1077             goto dopsksess;
1078         }
1079 
1080         /*
1081          * Obfuscate the age. Overflow here is fine, this addition is supposed
1082          * to be mod 2^32.
1083          */
1084         agems += s->session->ext.tick_age_add;
1085 
1086         reshashsize = EVP_MD_size(mdres);
1087         s->ext.tick_identity++;
1088         dores = 1;
1089     }
1090 
1091  dopsksess:
1092     if (!dores && s->psksession == NULL)
1093         return EXT_RETURN_NOT_SENT;
1094 
1095     if (s->psksession != NULL) {
1096         mdpsk = ssl_md(s->psksession->cipher->algorithm2);
1097         if (mdpsk == NULL) {
1098             /*
1099              * Don't recognize this cipher so we can't use the session.
1100              * If this happens it's an application bug.
1101              */
1102             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1103                      SSL_R_BAD_PSK);
1104             return EXT_RETURN_FAIL;
1105         }
1106 
1107         if (s->hello_retry_request == SSL_HRR_PENDING && mdpsk != handmd) {
1108             /*
1109              * Selected ciphersuite hash does not match the hash for the PSK
1110              * session. This is an application bug.
1111              */
1112             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1113                      SSL_R_BAD_PSK);
1114             return EXT_RETURN_FAIL;
1115         }
1116 
1117         pskhashsize = EVP_MD_size(mdpsk);
1118     }
1119 
1120     /* Create the extension, but skip over the binder for now */
1121     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
1122             || !WPACKET_start_sub_packet_u16(pkt)
1123             || !WPACKET_start_sub_packet_u16(pkt)) {
1124         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1125                  ERR_R_INTERNAL_ERROR);
1126         return EXT_RETURN_FAIL;
1127     }
1128 
1129     if (dores) {
1130         if (!WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick,
1131                                            s->session->ext.ticklen)
1132                 || !WPACKET_put_bytes_u32(pkt, agems)) {
1133             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1134                      ERR_R_INTERNAL_ERROR);
1135             return EXT_RETURN_FAIL;
1136         }
1137     }
1138 
1139     if (s->psksession != NULL) {
1140         if (!WPACKET_sub_memcpy_u16(pkt, s->psksession_id,
1141                                     s->psksession_id_len)
1142                 || !WPACKET_put_bytes_u32(pkt, 0)) {
1143             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1144                      ERR_R_INTERNAL_ERROR);
1145             return EXT_RETURN_FAIL;
1146         }
1147         s->ext.tick_identity++;
1148     }
1149 
1150     if (!WPACKET_close(pkt)
1151             || !WPACKET_get_total_written(pkt, &binderoffset)
1152             || !WPACKET_start_sub_packet_u16(pkt)
1153             || (dores
1154                 && !WPACKET_sub_allocate_bytes_u8(pkt, reshashsize, &resbinder))
1155             || (s->psksession != NULL
1156                 && !WPACKET_sub_allocate_bytes_u8(pkt, pskhashsize, &pskbinder))
1157             || !WPACKET_close(pkt)
1158             || !WPACKET_close(pkt)
1159             || !WPACKET_get_total_written(pkt, &msglen)
1160                /*
1161                 * We need to fill in all the sub-packet lengths now so we can
1162                 * calculate the HMAC of the message up to the binders
1163                 */
1164             || !WPACKET_fill_lengths(pkt)) {
1165         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_CTOS_PSK,
1166                  ERR_R_INTERNAL_ERROR);
1167         return EXT_RETURN_FAIL;
1168     }
1169 
1170     msgstart = WPACKET_get_curr(pkt) - msglen;
1171 
1172     if (dores
1173             && tls_psk_do_binder(s, mdres, msgstart, binderoffset, NULL,
1174                                  resbinder, s->session, 1, 0) != 1) {
1175         /* SSLfatal() already called */
1176         return EXT_RETURN_FAIL;
1177     }
1178 
1179     if (s->psksession != NULL
1180             && tls_psk_do_binder(s, mdpsk, msgstart, binderoffset, NULL,
1181                                  pskbinder, s->psksession, 1, 1) != 1) {
1182         /* SSLfatal() already called */
1183         return EXT_RETURN_FAIL;
1184     }
1185 
1186     return EXT_RETURN_SENT;
1187 #else
1188     return EXT_RETURN_NOT_SENT;
1189 #endif
1190 }
1191 
1192 EXT_RETURN tls_construct_ctos_post_handshake_auth(SSL *s, WPACKET *pkt,
1193                                                   unsigned int context,
1194                                                   X509 *x, size_t chainidx)
1195 {
1196 #ifndef OPENSSL_NO_TLS1_3
1197     if (!s->pha_enabled)
1198         return EXT_RETURN_NOT_SENT;
1199 
1200     /* construct extension - 0 length, no contents */
1201     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_post_handshake_auth)
1202             || !WPACKET_start_sub_packet_u16(pkt)
1203             || !WPACKET_close(pkt)) {
1204         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1205                  SSL_F_TLS_CONSTRUCT_CTOS_POST_HANDSHAKE_AUTH,
1206                  ERR_R_INTERNAL_ERROR);
1207         return EXT_RETURN_FAIL;
1208     }
1209 
1210     s->post_handshake_auth = SSL_PHA_EXT_SENT;
1211 
1212     return EXT_RETURN_SENT;
1213 #else
1214     return EXT_RETURN_NOT_SENT;
1215 #endif
1216 }
1217 
1218 
1219 /*
1220  * Parse the server's renegotiation binding and abort if it's not right
1221  */
1222 int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
1223                                X509 *x, size_t chainidx)
1224 {
1225     size_t expected_len = s->s3->previous_client_finished_len
1226         + s->s3->previous_server_finished_len;
1227     size_t ilen;
1228     const unsigned char *data;
1229 
1230     /* Check for logic errors */
1231     if (!ossl_assert(expected_len == 0
1232                      || s->s3->previous_client_finished_len != 0)
1233         || !ossl_assert(expected_len == 0
1234                         || s->s3->previous_server_finished_len != 0)) {
1235         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1236                  ERR_R_INTERNAL_ERROR);
1237         return 0;
1238     }
1239 
1240     /* Parse the length byte */
1241     if (!PACKET_get_1_len(pkt, &ilen)) {
1242         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1243                  SSL_R_RENEGOTIATION_ENCODING_ERR);
1244         return 0;
1245     }
1246 
1247     /* Consistency check */
1248     if (PACKET_remaining(pkt) != ilen) {
1249         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1250                  SSL_R_RENEGOTIATION_ENCODING_ERR);
1251         return 0;
1252     }
1253 
1254     /* Check that the extension matches */
1255     if (ilen != expected_len) {
1256         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1257                  SSL_R_RENEGOTIATION_MISMATCH);
1258         return 0;
1259     }
1260 
1261     if (!PACKET_get_bytes(pkt, &data, s->s3->previous_client_finished_len)
1262         || memcmp(data, s->s3->previous_client_finished,
1263                   s->s3->previous_client_finished_len) != 0) {
1264         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1265                  SSL_R_RENEGOTIATION_MISMATCH);
1266         return 0;
1267     }
1268 
1269     if (!PACKET_get_bytes(pkt, &data, s->s3->previous_server_finished_len)
1270         || memcmp(data, s->s3->previous_server_finished,
1271                   s->s3->previous_server_finished_len) != 0) {
1272         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
1273                  SSL_R_RENEGOTIATION_MISMATCH);
1274         return 0;
1275     }
1276     s->s3->send_connection_binding = 1;
1277 
1278     return 1;
1279 }
1280 
1281 /* Parse the server's max fragment len extension packet */
1282 int tls_parse_stoc_maxfragmentlen(SSL *s, PACKET *pkt, unsigned int context,
1283                                   X509 *x, size_t chainidx)
1284 {
1285     unsigned int value;
1286 
1287     if (PACKET_remaining(pkt) != 1 || !PACKET_get_1(pkt, &value)) {
1288         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_MAXFRAGMENTLEN,
1289                  SSL_R_BAD_EXTENSION);
1290         return 0;
1291     }
1292 
1293     /* |value| should contains a valid max-fragment-length code. */
1294     if (!IS_MAX_FRAGMENT_LENGTH_EXT_VALID(value)) {
1295         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1296                  SSL_F_TLS_PARSE_STOC_MAXFRAGMENTLEN,
1297                  SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
1298         return 0;
1299     }
1300 
1301     /* Must be the same value as client-configured one who was sent to server */
1302     /*-
1303      * RFC 6066: if a client receives a maximum fragment length negotiation
1304      * response that differs from the length it requested, ...
1305      * It must abort with SSL_AD_ILLEGAL_PARAMETER alert
1306      */
1307     if (value != s->ext.max_fragment_len_mode) {
1308         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1309                  SSL_F_TLS_PARSE_STOC_MAXFRAGMENTLEN,
1310                  SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
1311         return 0;
1312     }
1313 
1314     /*
1315      * Maximum Fragment Length Negotiation succeeded.
1316      * The negotiated Maximum Fragment Length is binding now.
1317      */
1318     s->session->ext.max_fragment_len_mode = value;
1319 
1320     return 1;
1321 }
1322 
1323 int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, unsigned int context,
1324                                X509 *x, size_t chainidx)
1325 {
1326     if (s->ext.hostname == NULL) {
1327         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1328                  ERR_R_INTERNAL_ERROR);
1329         return 0;
1330     }
1331 
1332     if (PACKET_remaining(pkt) > 0) {
1333         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1334                  SSL_R_BAD_EXTENSION);
1335         return 0;
1336     }
1337 
1338     if (!s->hit) {
1339         if (s->session->ext.hostname != NULL) {
1340             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1341                      ERR_R_INTERNAL_ERROR);
1342             return 0;
1343         }
1344         s->session->ext.hostname = OPENSSL_strdup(s->ext.hostname);
1345         if (s->session->ext.hostname == NULL) {
1346             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SERVER_NAME,
1347                      ERR_R_INTERNAL_ERROR);
1348             return 0;
1349         }
1350     }
1351 
1352     return 1;
1353 }
1354 
1355 #ifndef OPENSSL_NO_EC
1356 int tls_parse_stoc_ec_pt_formats(SSL *s, PACKET *pkt, unsigned int context,
1357                                  X509 *x, size_t chainidx)
1358 {
1359     size_t ecpointformats_len;
1360     PACKET ecptformatlist;
1361 
1362     if (!PACKET_as_length_prefixed_1(pkt, &ecptformatlist)) {
1363         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS,
1364                  SSL_R_BAD_EXTENSION);
1365         return 0;
1366     }
1367     if (!s->hit) {
1368         ecpointformats_len = PACKET_remaining(&ecptformatlist);
1369         if (ecpointformats_len == 0) {
1370             SSLfatal(s, SSL_AD_DECODE_ERROR,
1371                      SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS, SSL_R_BAD_LENGTH);
1372             return 0;
1373         }
1374 
1375         s->ext.peer_ecpointformats_len = 0;
1376         OPENSSL_free(s->ext.peer_ecpointformats);
1377         s->ext.peer_ecpointformats = OPENSSL_malloc(ecpointformats_len);
1378         if (s->ext.peer_ecpointformats == NULL) {
1379             s->ext.peer_ecpointformats_len = 0;
1380             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1381                      SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
1382             return 0;
1383         }
1384 
1385         s->ext.peer_ecpointformats_len = ecpointformats_len;
1386 
1387         if (!PACKET_copy_bytes(&ecptformatlist,
1388                                s->ext.peer_ecpointformats,
1389                                ecpointformats_len)) {
1390             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
1391                      SSL_F_TLS_PARSE_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
1392             return 0;
1393         }
1394     }
1395 
1396     return 1;
1397 }
1398 #endif
1399 
1400 int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
1401                                   X509 *x, size_t chainidx)
1402 {
1403     if (s->ext.session_ticket_cb != NULL &&
1404         !s->ext.session_ticket_cb(s, PACKET_data(pkt),
1405                               PACKET_remaining(pkt),
1406                               s->ext.session_ticket_cb_arg)) {
1407         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
1408                  SSL_F_TLS_PARSE_STOC_SESSION_TICKET, SSL_R_BAD_EXTENSION);
1409         return 0;
1410     }
1411 
1412     if (!tls_use_ticket(s)) {
1413         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION,
1414                  SSL_F_TLS_PARSE_STOC_SESSION_TICKET, SSL_R_BAD_EXTENSION);
1415         return 0;
1416     }
1417     if (PACKET_remaining(pkt) > 0) {
1418         SSLfatal(s, SSL_AD_DECODE_ERROR,
1419                  SSL_F_TLS_PARSE_STOC_SESSION_TICKET, SSL_R_BAD_EXTENSION);
1420         return 0;
1421     }
1422 
1423     s->ext.ticket_expected = 1;
1424 
1425     return 1;
1426 }
1427 
1428 #ifndef OPENSSL_NO_OCSP
1429 int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, unsigned int context,
1430                                   X509 *x, size_t chainidx)
1431 {
1432     if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST) {
1433         /* We ignore this if the server sends a CertificateRequest */
1434         /* TODO(TLS1.3): Add support for this */
1435         return 1;
1436     }
1437 
1438     /*
1439      * MUST only be sent if we've requested a status
1440      * request message. In TLS <= 1.2 it must also be empty.
1441      */
1442     if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp) {
1443         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION,
1444                  SSL_F_TLS_PARSE_STOC_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
1445         return 0;
1446     }
1447     if (!SSL_IS_TLS13(s) && PACKET_remaining(pkt) > 0) {
1448         SSLfatal(s, SSL_AD_DECODE_ERROR,
1449                  SSL_F_TLS_PARSE_STOC_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
1450         return 0;
1451     }
1452 
1453     if (SSL_IS_TLS13(s)) {
1454         /* We only know how to handle this if it's for the first Certificate in
1455          * the chain. We ignore any other responses.
1456          */
1457         if (chainidx != 0)
1458             return 1;
1459 
1460         /* SSLfatal() already called */
1461         return tls_process_cert_status_body(s, pkt);
1462     }
1463 
1464     /* Set flag to expect CertificateStatus message */
1465     s->ext.status_expected = 1;
1466 
1467     return 1;
1468 }
1469 #endif
1470 
1471 
1472 #ifndef OPENSSL_NO_CT
1473 int tls_parse_stoc_sct(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1474                        size_t chainidx)
1475 {
1476     if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST) {
1477         /* We ignore this if the server sends it in a CertificateRequest */
1478         /* TODO(TLS1.3): Add support for this */
1479         return 1;
1480     }
1481 
1482     /*
1483      * Only take it if we asked for it - i.e if there is no CT validation
1484      * callback set, then a custom extension MAY be processing it, so we
1485      * need to let control continue to flow to that.
1486      */
1487     if (s->ct_validation_callback != NULL) {
1488         size_t size = PACKET_remaining(pkt);
1489 
1490         /* Simply copy it off for later processing */
1491         OPENSSL_free(s->ext.scts);
1492         s->ext.scts = NULL;
1493 
1494         s->ext.scts_len = (uint16_t)size;
1495         if (size > 0) {
1496             s->ext.scts = OPENSSL_malloc(size);
1497             if (s->ext.scts == NULL) {
1498                 s->ext.scts_len = 0;
1499                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SCT,
1500                          ERR_R_MALLOC_FAILURE);
1501                 return 0;
1502             }
1503             if (!PACKET_copy_bytes(pkt, s->ext.scts, size)) {
1504                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_SCT,
1505                          ERR_R_INTERNAL_ERROR);
1506                 return 0;
1507             }
1508         }
1509     } else {
1510         ENDPOINT role = (context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0
1511                         ? ENDPOINT_CLIENT : ENDPOINT_BOTH;
1512 
1513         /*
1514          * If we didn't ask for it then there must be a custom extension,
1515          * otherwise this is unsolicited.
1516          */
1517         if (custom_ext_find(&s->cert->custext, role,
1518                             TLSEXT_TYPE_signed_certificate_timestamp,
1519                             NULL) == NULL) {
1520             SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_F_TLS_PARSE_STOC_SCT,
1521                      SSL_R_BAD_EXTENSION);
1522             return 0;
1523         }
1524 
1525         if (!custom_ext_parse(s, context,
1526                              TLSEXT_TYPE_signed_certificate_timestamp,
1527                              PACKET_data(pkt), PACKET_remaining(pkt),
1528                              x, chainidx)) {
1529             /* SSLfatal already called */
1530             return 0;
1531         }
1532     }
1533 
1534     return 1;
1535 }
1536 #endif
1537 
1538 
1539 #ifndef OPENSSL_NO_NEXTPROTONEG
1540 /*
1541  * ssl_next_proto_validate validates a Next Protocol Negotiation block. No
1542  * elements of zero length are allowed and the set of elements must exactly
1543  * fill the length of the block. Returns 1 on success or 0 on failure.
1544  */
1545 static int ssl_next_proto_validate(SSL *s, PACKET *pkt)
1546 {
1547     PACKET tmp_protocol;
1548 
1549     while (PACKET_remaining(pkt)) {
1550         if (!PACKET_get_length_prefixed_1(pkt, &tmp_protocol)
1551             || PACKET_remaining(&tmp_protocol) == 0) {
1552             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL_NEXT_PROTO_VALIDATE,
1553                      SSL_R_BAD_EXTENSION);
1554             return 0;
1555         }
1556     }
1557 
1558     return 1;
1559 }
1560 
1561 int tls_parse_stoc_npn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1562                        size_t chainidx)
1563 {
1564     unsigned char *selected;
1565     unsigned char selected_len;
1566     PACKET tmppkt;
1567 
1568     /* Check if we are in a renegotiation. If so ignore this extension */
1569     if (!SSL_IS_FIRST_HANDSHAKE(s))
1570         return 1;
1571 
1572     /* We must have requested it. */
1573     if (s->ctx->ext.npn_select_cb == NULL) {
1574         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_F_TLS_PARSE_STOC_NPN,
1575                  SSL_R_BAD_EXTENSION);
1576         return 0;
1577     }
1578 
1579     /* The data must be valid */
1580     tmppkt = *pkt;
1581     if (!ssl_next_proto_validate(s, &tmppkt)) {
1582         /* SSLfatal() already called */
1583         return 0;
1584     }
1585     if (s->ctx->ext.npn_select_cb(s, &selected, &selected_len,
1586                                   PACKET_data(pkt),
1587                                   PACKET_remaining(pkt),
1588                                   s->ctx->ext.npn_select_cb_arg) !=
1589              SSL_TLSEXT_ERR_OK) {
1590         SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PARSE_STOC_NPN,
1591                  SSL_R_BAD_EXTENSION);
1592         return 0;
1593     }
1594 
1595     /*
1596      * Could be non-NULL if server has sent multiple NPN extensions in
1597      * a single Serverhello
1598      */
1599     OPENSSL_free(s->ext.npn);
1600     s->ext.npn = OPENSSL_malloc(selected_len);
1601     if (s->ext.npn == NULL) {
1602         s->ext.npn_len = 0;
1603         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_NPN,
1604                  ERR_R_INTERNAL_ERROR);
1605         return 0;
1606     }
1607 
1608     memcpy(s->ext.npn, selected, selected_len);
1609     s->ext.npn_len = selected_len;
1610     s->s3->npn_seen = 1;
1611 
1612     return 1;
1613 }
1614 #endif
1615 
1616 int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1617                         size_t chainidx)
1618 {
1619     size_t len;
1620 
1621     /* We must have requested it. */
1622     if (!s->s3->alpn_sent) {
1623         SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, SSL_F_TLS_PARSE_STOC_ALPN,
1624                  SSL_R_BAD_EXTENSION);
1625         return 0;
1626     }
1627     /*-
1628      * The extension data consists of:
1629      *   uint16 list_length
1630      *   uint8 proto_length;
1631      *   uint8 proto[proto_length];
1632      */
1633     if (!PACKET_get_net_2_len(pkt, &len)
1634         || PACKET_remaining(pkt) != len || !PACKET_get_1_len(pkt, &len)
1635         || PACKET_remaining(pkt) != len) {
1636         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1637                  SSL_R_BAD_EXTENSION);
1638         return 0;
1639     }
1640     OPENSSL_free(s->s3->alpn_selected);
1641     s->s3->alpn_selected = OPENSSL_malloc(len);
1642     if (s->s3->alpn_selected == NULL) {
1643         s->s3->alpn_selected_len = 0;
1644         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1645                  ERR_R_INTERNAL_ERROR);
1646         return 0;
1647     }
1648     if (!PACKET_copy_bytes(pkt, s->s3->alpn_selected, len)) {
1649         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1650                  SSL_R_BAD_EXTENSION);
1651         return 0;
1652     }
1653     s->s3->alpn_selected_len = len;
1654 
1655     if (s->session->ext.alpn_selected == NULL
1656             || s->session->ext.alpn_selected_len != len
1657             || memcmp(s->session->ext.alpn_selected, s->s3->alpn_selected, len)
1658                != 0) {
1659         /* ALPN not consistent with the old session so cannot use early_data */
1660         s->ext.early_data_ok = 0;
1661     }
1662     if (!s->hit) {
1663         /*
1664          * This is a new session and so alpn_selected should have been
1665          * initialised to NULL. We should update it with the selected ALPN.
1666          */
1667         if (!ossl_assert(s->session->ext.alpn_selected == NULL)) {
1668             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1669                      ERR_R_INTERNAL_ERROR);
1670             return 0;
1671         }
1672         s->session->ext.alpn_selected =
1673             OPENSSL_memdup(s->s3->alpn_selected, s->s3->alpn_selected_len);
1674         if (s->session->ext.alpn_selected == NULL) {
1675             s->session->ext.alpn_selected_len = 0;
1676             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_ALPN,
1677                      ERR_R_INTERNAL_ERROR);
1678             return 0;
1679         }
1680         s->session->ext.alpn_selected_len = s->s3->alpn_selected_len;
1681     }
1682 
1683     return 1;
1684 }
1685 
1686 #ifndef OPENSSL_NO_SRTP
1687 int tls_parse_stoc_use_srtp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1688                             size_t chainidx)
1689 {
1690     unsigned int id, ct, mki;
1691     int i;
1692     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
1693     SRTP_PROTECTION_PROFILE *prof;
1694 
1695     if (!PACKET_get_net_2(pkt, &ct) || ct != 2
1696             || !PACKET_get_net_2(pkt, &id)
1697             || !PACKET_get_1(pkt, &mki)
1698             || PACKET_remaining(pkt) != 0) {
1699         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1700                  SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
1701         return 0;
1702     }
1703 
1704     if (mki != 0) {
1705         /* Must be no MKI, since we never offer one */
1706         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1707                  SSL_R_BAD_SRTP_MKI_VALUE);
1708         return 0;
1709     }
1710 
1711     /* Throw an error if the server gave us an unsolicited extension */
1712     clnt = SSL_get_srtp_profiles(s);
1713     if (clnt == NULL) {
1714         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1715                  SSL_R_NO_SRTP_PROFILES);
1716         return 0;
1717     }
1718 
1719     /*
1720      * Check to see if the server gave us something we support (and
1721      * presumably offered)
1722      */
1723     for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) {
1724         prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
1725 
1726         if (prof->id == id) {
1727             s->srtp_profile = prof;
1728             return 1;
1729         }
1730     }
1731 
1732     SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_USE_SRTP,
1733              SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
1734     return 0;
1735 }
1736 #endif
1737 
1738 int tls_parse_stoc_etm(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1739                        size_t chainidx)
1740 {
1741     /* Ignore if inappropriate ciphersuite */
1742     if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
1743             && s->s3->tmp.new_cipher->algorithm_mac != SSL_AEAD
1744             && s->s3->tmp.new_cipher->algorithm_enc != SSL_RC4
1745             && s->s3->tmp.new_cipher->algorithm_enc != SSL_eGOST2814789CNT
1746             && s->s3->tmp.new_cipher->algorithm_enc != SSL_eGOST2814789CNT12)
1747         s->ext.use_etm = 1;
1748 
1749     return 1;
1750 }
1751 
1752 int tls_parse_stoc_ems(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1753                        size_t chainidx)
1754 {
1755     s->s3->flags |= TLS1_FLAGS_RECEIVED_EXTMS;
1756     if (!s->hit)
1757         s->session->flags |= SSL_SESS_FLAG_EXTMS;
1758 
1759     return 1;
1760 }
1761 
1762 int tls_parse_stoc_supported_versions(SSL *s, PACKET *pkt, unsigned int context,
1763                                       X509 *x, size_t chainidx)
1764 {
1765     unsigned int version;
1766 
1767     if (!PACKET_get_net_2(pkt, &version)
1768             || PACKET_remaining(pkt) != 0) {
1769         SSLfatal(s, SSL_AD_DECODE_ERROR,
1770                  SSL_F_TLS_PARSE_STOC_SUPPORTED_VERSIONS,
1771                  SSL_R_LENGTH_MISMATCH);
1772         return 0;
1773     }
1774 
1775     /*
1776      * The only protocol version we support which is valid in this extension in
1777      * a ServerHello is TLSv1.3 therefore we shouldn't be getting anything else.
1778      */
1779     if (version != TLS1_3_VERSION) {
1780         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1781                  SSL_F_TLS_PARSE_STOC_SUPPORTED_VERSIONS,
1782                  SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
1783         return 0;
1784     }
1785 
1786     /* We ignore this extension for HRRs except to sanity check it */
1787     if (context == SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)
1788         return 1;
1789 
1790     /* We just set it here. We validate it in ssl_choose_client_version */
1791     s->version = version;
1792 
1793     return 1;
1794 }
1795 
1796 int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1797                              size_t chainidx)
1798 {
1799 #ifndef OPENSSL_NO_TLS1_3
1800     unsigned int group_id;
1801     PACKET encoded_pt;
1802     EVP_PKEY *ckey = s->s3->tmp.pkey, *skey = NULL;
1803 
1804     /* Sanity check */
1805     if (ckey == NULL || s->s3->peer_tmp != NULL) {
1806         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1807                  ERR_R_INTERNAL_ERROR);
1808         return 0;
1809     }
1810 
1811     if (!PACKET_get_net_2(pkt, &group_id)) {
1812         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1813                  SSL_R_LENGTH_MISMATCH);
1814         return 0;
1815     }
1816 
1817     if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0) {
1818         const uint16_t *pgroups = NULL;
1819         size_t i, num_groups;
1820 
1821         if (PACKET_remaining(pkt) != 0) {
1822             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1823                      SSL_R_LENGTH_MISMATCH);
1824             return 0;
1825         }
1826 
1827         /*
1828          * It is an error if the HelloRetryRequest wants a key_share that we
1829          * already sent in the first ClientHello
1830          */
1831         if (group_id == s->s3->group_id) {
1832             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1833                      SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
1834             return 0;
1835         }
1836 
1837         /* Validate the selected group is one we support */
1838         tls1_get_supported_groups(s, &pgroups, &num_groups);
1839         for (i = 0; i < num_groups; i++) {
1840             if (group_id == pgroups[i])
1841                 break;
1842         }
1843         if (i >= num_groups
1844                 || !tls_curve_allowed(s, group_id, SSL_SECOP_CURVE_SUPPORTED)) {
1845             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
1846                      SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
1847             return 0;
1848         }
1849 
1850         s->s3->group_id = group_id;
1851         EVP_PKEY_free(s->s3->tmp.pkey);
1852         s->s3->tmp.pkey = NULL;
1853         return 1;
1854     }
1855 
1856     if (group_id != s->s3->group_id) {
1857         /*
1858          * This isn't for the group that we sent in the original
1859          * key_share!
1860          */
1861         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1862                  SSL_R_BAD_KEY_SHARE);
1863         return 0;
1864     }
1865 
1866     if (!PACKET_as_length_prefixed_2(pkt, &encoded_pt)
1867             || PACKET_remaining(&encoded_pt) == 0) {
1868         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1869                  SSL_R_LENGTH_MISMATCH);
1870         return 0;
1871     }
1872 
1873     skey = EVP_PKEY_new();
1874     if (skey == NULL || EVP_PKEY_copy_parameters(skey, ckey) <= 0) {
1875         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1876                  ERR_R_MALLOC_FAILURE);
1877         EVP_PKEY_free(skey);
1878         return 0;
1879     }
1880     if (!EVP_PKEY_set1_tls_encodedpoint(skey, PACKET_data(&encoded_pt),
1881                                         PACKET_remaining(&encoded_pt))) {
1882         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_KEY_SHARE,
1883                  SSL_R_BAD_ECPOINT);
1884         EVP_PKEY_free(skey);
1885         return 0;
1886     }
1887 
1888     if (ssl_derive(s, ckey, skey, 1) == 0) {
1889         /* SSLfatal() already called */
1890         EVP_PKEY_free(skey);
1891         return 0;
1892     }
1893     s->s3->peer_tmp = skey;
1894 #endif
1895 
1896     return 1;
1897 }
1898 
1899 int tls_parse_stoc_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1900                        size_t chainidx)
1901 {
1902     PACKET cookie;
1903 
1904     if (!PACKET_as_length_prefixed_2(pkt, &cookie)
1905             || !PACKET_memdup(&cookie, &s->ext.tls13_cookie,
1906                               &s->ext.tls13_cookie_len)) {
1907         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_COOKIE,
1908                  SSL_R_LENGTH_MISMATCH);
1909         return 0;
1910     }
1911 
1912     return 1;
1913 }
1914 
1915 int tls_parse_stoc_early_data(SSL *s, PACKET *pkt, unsigned int context,
1916                               X509 *x, size_t chainidx)
1917 {
1918     if (context == SSL_EXT_TLS1_3_NEW_SESSION_TICKET) {
1919         unsigned long max_early_data;
1920 
1921         if (!PACKET_get_net_4(pkt, &max_early_data)
1922                 || PACKET_remaining(pkt) != 0) {
1923             SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_EARLY_DATA,
1924                      SSL_R_INVALID_MAX_EARLY_DATA);
1925             return 0;
1926         }
1927 
1928         s->session->ext.max_early_data = max_early_data;
1929 
1930         return 1;
1931     }
1932 
1933     if (PACKET_remaining(pkt) != 0) {
1934         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_EARLY_DATA,
1935                  SSL_R_BAD_EXTENSION);
1936         return 0;
1937     }
1938 
1939     if (!s->ext.early_data_ok
1940             || !s->hit) {
1941         /*
1942          * If we get here then we didn't send early data, or we didn't resume
1943          * using the first identity, or the SNI/ALPN is not consistent so the
1944          * server should not be accepting it.
1945          */
1946         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_EARLY_DATA,
1947                  SSL_R_BAD_EXTENSION);
1948         return 0;
1949     }
1950 
1951     s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1952 
1953     return 1;
1954 }
1955 
1956 int tls_parse_stoc_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
1957                        size_t chainidx)
1958 {
1959 #ifndef OPENSSL_NO_TLS1_3
1960     unsigned int identity;
1961 
1962     if (!PACKET_get_net_2(pkt, &identity) || PACKET_remaining(pkt) != 0) {
1963         SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_STOC_PSK,
1964                  SSL_R_LENGTH_MISMATCH);
1965         return 0;
1966     }
1967 
1968     if (identity >= (unsigned int)s->ext.tick_identity) {
1969         SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_STOC_PSK,
1970                  SSL_R_BAD_PSK_IDENTITY);
1971         return 0;
1972     }
1973 
1974     /*
1975      * Session resumption tickets are always sent before PSK tickets. If the
1976      * ticket index is 0 then it must be for a session resumption ticket if we
1977      * sent two tickets, or if we didn't send a PSK ticket.
1978      */
1979     if (identity == 0 && (s->psksession == NULL || s->ext.tick_identity == 2)) {
1980         s->hit = 1;
1981         SSL_SESSION_free(s->psksession);
1982         s->psksession = NULL;
1983         return 1;
1984     }
1985 
1986     if (s->psksession == NULL) {
1987         /* Should never happen */
1988         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_STOC_PSK,
1989                  ERR_R_INTERNAL_ERROR);
1990         return 0;
1991     }
1992 
1993     /*
1994      * If we used the external PSK for sending early_data then s->early_secret
1995      * is already set up, so don't overwrite it. Otherwise we copy the
1996      * early_secret across that we generated earlier.
1997      */
1998     if ((s->early_data_state != SSL_EARLY_DATA_WRITE_RETRY
1999                 && s->early_data_state != SSL_EARLY_DATA_FINISHED_WRITING)
2000             || s->session->ext.max_early_data > 0
2001             || s->psksession->ext.max_early_data == 0)
2002         memcpy(s->early_secret, s->psksession->early_secret, EVP_MAX_MD_SIZE);
2003 
2004     SSL_SESSION_free(s->session);
2005     s->session = s->psksession;
2006     s->psksession = NULL;
2007     s->hit = 1;
2008     /* Early data is only allowed if we used the first ticket */
2009     if (identity != 0)
2010         s->ext.early_data_ok = 0;
2011 #endif
2012 
2013     return 1;
2014 }
2015