2 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
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
11 #include "../ssl_locl.h"
12 #include "statem_locl.h"
14 static int final_renegotiate(SSL *s, unsigned int context, int sent,
16 static int init_server_name(SSL *s, unsigned int context);
17 static int final_server_name(SSL *s, unsigned int context, int sent,
20 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
23 static int init_session_ticket(SSL *s, unsigned int context);
24 #ifndef OPENSSL_NO_OCSP
25 static int init_status_request(SSL *s, unsigned int context);
27 #ifndef OPENSSL_NO_NEXTPROTONEG
28 static int init_npn(SSL *s, unsigned int context);
30 static int init_alpn(SSL *s, unsigned int context);
31 static int final_alpn(SSL *s, unsigned int context, int sent, int *al);
32 static int init_sig_algs(SSL *s, unsigned int context);
33 #ifndef OPENSSL_NO_SRP
34 static int init_srp(SSL *s, unsigned int context);
36 static int init_etm(SSL *s, unsigned int context);
37 static int init_ems(SSL *s, unsigned int context);
38 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
39 static int init_psk_kex_modes(SSL *s, unsigned int context);
41 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
43 #ifndef OPENSSL_NO_SRTP
44 static int init_srtp(SSL *s, unsigned int context);
46 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
47 static int final_early_data(SSL *s, unsigned int context, int sent, int *al);
49 /* Structure to define a built-in extension */
50 typedef struct extensions_definition_st {
51 /* The defined type for the extension */
54 * The context that this extension applies to, e.g. what messages and
59 * Initialise extension before parsing. Always called for relevant contexts
60 * even if extension not present
62 int (*init)(SSL *s, unsigned int context);
63 /* Parse extension sent from client to server */
64 int (*parse_ctos)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
65 size_t chainidx, int *al);
66 /* Parse extension send from server to client */
67 int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
68 size_t chainidx, int *al);
69 /* Construct extension sent from server to client */
70 int (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
71 size_t chainidx, int *al);
72 /* Construct extension sent from client to server */
73 int (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
74 size_t chainidx, int *al);
76 * Finalise extension after parsing. Always called where an extensions was
77 * initialised even if the extension was not present. |sent| is set to 1 if
78 * the extension was seen, or 0 otherwise.
80 int (*final)(SSL *s, unsigned int context, int sent, int *al);
81 } EXTENSION_DEFINITION;
84 * Definitions of all built-in extensions. NOTE: Changes in the number or order
85 * of these extensions should be mirrored with equivalent changes to the
86 * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
87 * Each extension has an initialiser, a client and
88 * server side parser and a finaliser. The initialiser is called (if the
89 * extension is relevant to the given context) even if we did not see the
90 * extension in the message that we received. The parser functions are only
91 * called if we see the extension in the message. The finalisers are always
92 * called if the initialiser was called.
93 * There are also server and client side constructor functions which are always
94 * called during message construction if the extension is relevant for the
96 * The initialisation, parsing, finalisation and construction functions are
97 * always called in the order defined in this list. Some extensions may depend
98 * on others having been processed first, so the order of this list is
100 * The extension context is defined by a series of flags which specify which
101 * messages the extension is relevant to. These flags also specify whether the
102 * extension is relevant to a particular protocol or protocol version.
104 * TODO(TLS1.3): Make sure we have a test to check the consistency of these
106 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL }
107 static const EXTENSION_DEFINITION ext_defs[] = {
109 TLSEXT_TYPE_renegotiate,
110 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_SSL3_ALLOWED
111 | EXT_TLS1_2_AND_BELOW_ONLY,
112 NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
113 tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
117 TLSEXT_TYPE_server_name,
118 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
119 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
121 tls_parse_ctos_server_name, tls_parse_stoc_server_name,
122 tls_construct_stoc_server_name, tls_construct_ctos_server_name,
125 #ifndef OPENSSL_NO_SRP
128 EXT_CLIENT_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
129 init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
135 TLSEXT_TYPE_early_data_info,
136 EXT_TLS1_3_NEW_SESSION_TICKET,
137 NULL, NULL, tls_parse_stoc_early_data_info,
138 tls_construct_stoc_early_data_info, NULL, NULL
140 #ifndef OPENSSL_NO_EC
142 TLSEXT_TYPE_ec_point_formats,
143 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
144 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
145 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
149 TLSEXT_TYPE_supported_groups,
150 EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
151 NULL, tls_parse_ctos_supported_groups, NULL,
152 NULL /* TODO(TLS1.3): Need to add this */,
153 tls_construct_ctos_supported_groups, NULL
160 TLSEXT_TYPE_session_ticket,
161 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
162 init_session_ticket, tls_parse_ctos_session_ticket,
163 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
164 tls_construct_ctos_session_ticket, NULL
167 TLSEXT_TYPE_signature_algorithms,
169 init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
170 tls_construct_ctos_sig_algs, final_sig_algs
172 #ifndef OPENSSL_NO_OCSP
174 TLSEXT_TYPE_status_request,
175 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
176 | EXT_TLS1_3_CERTIFICATE,
177 init_status_request, tls_parse_ctos_status_request,
178 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
179 tls_construct_ctos_status_request, NULL
184 #ifndef OPENSSL_NO_NEXTPROTONEG
186 TLSEXT_TYPE_next_proto_neg,
187 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
188 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
189 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
196 * Must appear in this list after server_name so that finalisation
197 * happens after server_name callbacks
199 TLSEXT_TYPE_application_layer_protocol_negotiation,
200 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
201 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
202 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
203 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
205 #ifndef OPENSSL_NO_SRTP
207 TLSEXT_TYPE_use_srtp,
208 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
209 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS | EXT_DTLS_ONLY,
210 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
211 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
217 TLSEXT_TYPE_encrypt_then_mac,
218 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY | EXT_SSL3_ALLOWED,
219 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
220 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
222 #ifndef OPENSSL_NO_CT
224 TLSEXT_TYPE_signed_certificate_timestamp,
225 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
226 | EXT_TLS1_3_CERTIFICATE,
229 * No server side support for this, but can be provided by a custom
230 * extension. This is an exception to the rule that custom extensions
231 * cannot override built in ones.
233 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
239 TLSEXT_TYPE_extended_master_secret,
240 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
241 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
242 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
245 TLSEXT_TYPE_supported_versions,
246 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
248 /* Processed inline as part of version selection */
249 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
252 TLSEXT_TYPE_psk_kex_modes,
253 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
254 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
255 tls_construct_ctos_psk_kex_modes, NULL
257 #ifndef OPENSSL_NO_EC
260 * Must be in this list after supported_groups. We need that to have
261 * been parsed before we do this one.
263 TLSEXT_TYPE_key_share,
264 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO
265 | EXT_TLS1_3_HELLO_RETRY_REQUEST | EXT_TLS_IMPLEMENTATION_ONLY
267 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
268 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
274 EXT_CLIENT_HELLO | EXT_TLS1_3_HELLO_RETRY_REQUEST
275 | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
276 NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
281 * Special unsolicited ServerHello extension only used when
282 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
284 TLSEXT_TYPE_cryptopro_bug,
285 EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
286 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
289 TLSEXT_TYPE_early_data,
290 EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
291 NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data,
292 tls_construct_stoc_early_data, tls_construct_ctos_early_data,
296 /* Must be immediately before pre_shared_key */
297 /* TODO(TLS1.3): Fix me */
301 /* We send this, but don't read it */
302 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
305 /* Required by the TLSv1.3 spec to always be the last extension */
307 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO | EXT_TLS_IMPLEMENTATION_ONLY
309 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
310 tls_construct_ctos_psk, NULL
315 * Verify whether we are allowed to use the extension |type| in the current
316 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
317 * indicate the extension is not allowed. If returning 1 then |*found| is set to
318 * 1 if we found a definition for the extension, and |*idx| is set to its index
320 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
321 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
322 RAW_EXTENSION **found)
325 size_t builtin_num = OSSL_NELEM(ext_defs);
326 const EXTENSION_DEFINITION *thisext;
328 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
329 if (type == thisext->type) {
330 /* Check we're allowed to use this extension in this context */
331 if ((context & thisext->context) == 0)
334 if (SSL_IS_DTLS(s)) {
335 if ((thisext->context & EXT_TLS_ONLY) != 0)
337 } else if ((thisext->context & EXT_DTLS_ONLY) != 0) {
341 *found = &rawexlist[i];
346 if ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) == 0) {
348 * Custom extensions only apply to <=TLS1.2. This extension is unknown
349 * in this context - we allow it
355 /* Check the custom extensions */
357 for (i = builtin_num; i < builtin_num + meths->meths_count; i++) {
358 if (meths->meths[i - builtin_num].ext_type == type) {
359 *found = &rawexlist[i];
365 /* Unknown extension. We allow it */
371 * Check whether the context defined for an extension |extctx| means whether
372 * the extension is relevant for the current context |thisctx| or not. Returns
373 * 1 if the extension is relevant for this context, and 0 otherwise
375 static int extension_is_relevant(SSL *s, unsigned int extctx,
376 unsigned int thisctx)
379 && (extctx & EXT_TLS_IMPLEMENTATION_ONLY) != 0)
380 || (s->version == SSL3_VERSION
381 && (extctx & EXT_SSL3_ALLOWED) == 0)
383 && (extctx & EXT_TLS1_2_AND_BELOW_ONLY) != 0)
384 || (!SSL_IS_TLS13(s) && (extctx & EXT_TLS1_3_ONLY) != 0))
391 * Gather a list of all the extensions from the data in |packet]. |context|
392 * tells us which message this extension is for. The raw extension data is
393 * stored in |*res| on success. In the event of an error the alert type to use
394 * is stored in |*al|. We don't actually process the content of the extensions
395 * yet, except to check their types. This function also runs the initialiser
396 * functions for all known extensions (whether we have collected them or not).
397 * If successful the caller is responsible for freeing the contents of |*res|.
399 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
400 * more than one extension of the same type in a ClientHello or ServerHello.
401 * This function returns 1 if all extensions are unique and we have parsed their
402 * types, and 0 if the extensions contain duplicates, could not be successfully
403 * found, or an internal error occurred. We only check duplicates for
404 * extensions that we know about. We ignore others.
406 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
407 RAW_EXTENSION **res, int *al, size_t *len)
409 PACKET extensions = *packet;
412 custom_ext_methods *exts = NULL;
413 RAW_EXTENSION *raw_extensions = NULL;
414 const EXTENSION_DEFINITION *thisexd;
419 * Initialise server side custom extensions. Client side is done during
420 * construction of extensions for the ClientHello.
422 if ((context & EXT_CLIENT_HELLO) != 0) {
423 exts = &s->cert->srv_ext;
424 custom_ext_init(&s->cert->srv_ext);
425 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
426 exts = &s->cert->cli_ext;
429 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
430 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
431 if (raw_extensions == NULL) {
432 *al = SSL_AD_INTERNAL_ERROR;
433 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
437 while (PACKET_remaining(&extensions) > 0) {
440 RAW_EXTENSION *thisex;
442 if (!PACKET_get_net_2(&extensions, &type) ||
443 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
444 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
445 *al = SSL_AD_DECODE_ERROR;
449 * Verify this extension is allowed. We only check duplicates for
450 * extensions that we recognise. We also have a special case for the
451 * PSK extension, which must be the last one in the ClientHello.
453 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
454 || (thisex != NULL && thisex->present == 1)
455 || (type == TLSEXT_TYPE_psk
456 && (context & EXT_CLIENT_HELLO) != 0
457 && PACKET_remaining(&extensions) != 0)) {
458 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
459 *al = SSL_AD_ILLEGAL_PARAMETER;
462 if (thisex != NULL) {
463 thisex->data = extension;
470 * Initialise all known extensions relevant to this context, whether we have
473 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
474 if(thisexd->init != NULL && (thisexd->context & context) != 0
475 && extension_is_relevant(s, thisexd->context, context)
476 && !thisexd->init(s, context)) {
477 *al = SSL_AD_INTERNAL_ERROR;
482 *res = raw_extensions;
488 OPENSSL_free(raw_extensions);
493 * Runs the parser for a given extension with index |idx|. |exts| contains the
494 * list of all parsed extensions previously collected by
495 * tls_collect_extensions(). The parser is only run if it is applicable for the
496 * given |context| and the parser has not already been run. If this is for a
497 * Certificate message, then we also provide the parser with the relevant
498 * Certificate |x| and its position in the |chainidx| with 0 being the first
499 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
500 * |*al| is populated with a suitable alert code. If an extension is not present
501 * this counted as success.
503 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
504 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
506 RAW_EXTENSION *currext = &exts[idx];
507 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
508 size_t chainidx, int *al) = NULL;
510 /* Skip if the extension is not present */
511 if (!currext->present)
515 s->ext.debug_cb(s, !s->server, currext->type,
516 PACKET_data(&currext->data),
517 PACKET_remaining(&currext->data),
520 /* Skip if we've already parsed this extension */
526 if (idx < OSSL_NELEM(ext_defs)) {
527 /* We are handling a built-in extension */
528 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
530 /* Check if extension is defined for our protocol. If not, skip */
531 if (!extension_is_relevant(s, extdef->context, context))
534 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
537 return parser(s, &currext->data, context, x, chainidx, al);
540 * If the parser is NULL we fall through to the custom extension
546 * This is a custom extension. We only allow this if it is a non
547 * resumed session on the server side.
549 * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
550 * We're going to need a new mechanism for TLS1.3 to specify which
551 * messages to add the custom extensions to.
553 if ((!s->hit || !s->server)
555 & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
556 && custom_ext_parse(s, s->server, currext->type,
557 PACKET_data(&currext->data),
558 PACKET_remaining(&currext->data),
566 * Parse all remaining extensions that have not yet been parsed. Also calls the
567 * finalisation for all extensions at the end, whether we collected them or not.
568 * Returns 1 for success or 0 for failure. If we are working on a Certificate
569 * message then we also pass the Certificate |x| and its position in the
570 * |chainidx|, with 0 being the first certificate. On failure, |*al| is
571 * populated with a suitable alert code.
573 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
574 size_t chainidx, int *al)
576 size_t i, numexts = OSSL_NELEM(ext_defs);
577 const EXTENSION_DEFINITION *thisexd;
579 /* Calculate the number of extensions in the extensions list */
580 if ((context & EXT_CLIENT_HELLO) != 0) {
581 numexts += s->cert->srv_ext.meths_count;
582 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
583 numexts += s->cert->cli_ext.meths_count;
586 /* Parse each extension in turn */
587 for (i = 0; i < numexts; i++) {
588 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
593 * Finalise all known extensions relevant to this context, whether we have
596 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
597 if(thisexd->final != NULL
598 && (thisexd->context & context) != 0
599 && !thisexd->final(s, context, exts[i].present, al))
607 * Construct all the extensions relevant to the current |context| and write
608 * them to |pkt|. If this is an extension for a Certificate in a Certificate
609 * message, then |x| will be set to the Certificate we are handling, and
610 * |chainidx| will indicate the position in the chainidx we are processing (with
611 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
612 * failure occurs then |al| is populated with a suitable alert code. On a
613 * failure construction stops at the first extension to fail to construct.
615 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
616 X509 *x, size_t chainidx, int *al)
619 int addcustom = 0, min_version, max_version = 0, reason, tmpal;
620 const EXTENSION_DEFINITION *thisexd;
623 * Normally if something goes wrong during construction it's an internal
624 * error. We can always override this later.
626 tmpal = SSL_AD_INTERNAL_ERROR;
628 if (!WPACKET_start_sub_packet_u16(pkt)
630 * If extensions are of zero length then we don't even add the
631 * extensions length bytes to a ClientHello/ServerHello in SSLv3
633 || ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
634 && s->version == SSL3_VERSION
635 && !WPACKET_set_flags(pkt,
636 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
637 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
641 if ((context & EXT_CLIENT_HELLO) != 0) {
642 reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
644 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
649 /* Add custom extensions first */
650 if ((context & EXT_CLIENT_HELLO) != 0) {
651 custom_ext_init(&s->cert->cli_ext);
653 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
655 * We already initialised the custom extensions during ClientHello
658 * TODO(TLS1.3): We're going to need a new custom extension mechanism
659 * for TLS1.3, so that custom extensions can specify which of the
660 * multiple message they wish to add themselves to.
665 if (addcustom && !custom_ext_add(s, s->server, pkt, &tmpal)) {
666 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
670 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
671 int (*construct)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
672 size_t chainidx, int *al);
674 /* Skip if not relevant for our context */
675 if ((thisexd->context & context) == 0)
678 construct = s->server ? thisexd->construct_stoc
679 : thisexd->construct_ctos;
681 /* Check if this extension is defined for our protocol. If not, skip */
683 && (thisexd->context & EXT_TLS_IMPLEMENTATION_ONLY)
685 || (s->version == SSL3_VERSION
686 && (thisexd->context & EXT_SSL3_ALLOWED) == 0)
688 && (thisexd->context & EXT_TLS1_2_AND_BELOW_ONLY)
691 && (thisexd->context & EXT_TLS1_3_ONLY) != 0
692 && (context & EXT_CLIENT_HELLO) == 0)
693 || ((thisexd->context & EXT_TLS1_3_ONLY) != 0
694 && (context & EXT_CLIENT_HELLO) != 0
695 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
696 || construct == NULL)
699 if (!construct(s, pkt, context, x, chainidx, &tmpal))
703 if (!WPACKET_close(pkt)) {
704 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
716 * Built in extension finalisation and initialisation functions. All initialise
717 * or finalise the associated extension type for the given |context|. For
718 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
719 * otherwise. These functions return 1 on success or 0 on failure. In the event
720 * of a failure then |*al| is populated with a suitable error code.
723 static int final_renegotiate(SSL *s, unsigned int context, int sent,
728 * Check if we can connect to a server that doesn't support safe
731 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
732 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
734 *al = SSL_AD_HANDSHAKE_FAILURE;
735 SSLerr(SSL_F_FINAL_RENEGOTIATE,
736 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
743 /* Need RI if renegotiating */
745 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
747 *al = SSL_AD_HANDSHAKE_FAILURE;
748 SSLerr(SSL_F_FINAL_RENEGOTIATE,
749 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
757 static int init_server_name(SSL *s, unsigned int context)
760 s->servername_done = 0;
765 static int final_server_name(SSL *s, unsigned int context, int sent,
768 int ret = SSL_TLSEXT_ERR_NOACK;
769 int altmp = SSL_AD_UNRECOGNIZED_NAME;
771 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
772 ret = s->ctx->ext.servername_cb(s, &altmp,
773 s->ctx->ext.servername_arg);
774 else if (s->session_ctx != NULL
775 && s->session_ctx->ext.servername_cb != 0)
776 ret = s->session_ctx->ext.servername_cb(s, &altmp,
777 s->session_ctx->ext.servername_arg);
780 case SSL_TLSEXT_ERR_ALERT_FATAL:
784 case SSL_TLSEXT_ERR_ALERT_WARNING:
788 case SSL_TLSEXT_ERR_NOACK:
789 s->servername_done = 0;
797 #ifndef OPENSSL_NO_EC
798 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
801 unsigned long alg_k, alg_a;
806 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
807 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
810 * If we are client and using an elliptic curve cryptography cipher
811 * suite, then if server returns an EC point formats lists extension it
812 * must contain uncompressed.
814 if (s->ext.ecpointformats != NULL
815 && s->ext.ecpointformats_len > 0
816 && s->session->ext.ecpointformats != NULL
817 && s->session->ext.ecpointformats_len > 0
818 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
819 /* we are using an ECC cipher */
821 unsigned char *list = s->session->ext.ecpointformats;
823 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
824 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
827 if (i == s->session->ext.ecpointformats_len) {
828 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
829 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
838 static int init_session_ticket(SSL *s, unsigned int context)
841 s->ext.ticket_expected = 0;
846 #ifndef OPENSSL_NO_OCSP
847 static int init_status_request(SSL *s, unsigned int context)
850 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
853 * Ensure we get sensible values passed to tlsext_status_cb in the event
854 * that we don't receive a status message
856 OPENSSL_free(s->ext.ocsp.resp);
857 s->ext.ocsp.resp = NULL;
858 s->ext.ocsp.resp_len = 0;
865 #ifndef OPENSSL_NO_NEXTPROTONEG
866 static int init_npn(SSL *s, unsigned int context)
874 static int init_alpn(SSL *s, unsigned int context)
876 OPENSSL_free(s->s3->alpn_selected);
877 s->s3->alpn_selected = NULL;
879 s->s3->alpn_selected_len = 0;
880 OPENSSL_free(s->s3->alpn_proposed);
881 s->s3->alpn_proposed = NULL;
882 s->s3->alpn_proposed_len = 0;
887 static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
889 const unsigned char *selected = NULL;
890 unsigned char selected_len = 0;
895 if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
896 int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
897 s->s3->alpn_proposed,
898 (unsigned int)s->s3->alpn_proposed_len,
899 s->ctx->ext.alpn_select_cb_arg);
901 if (r == SSL_TLSEXT_ERR_OK) {
902 OPENSSL_free(s->s3->alpn_selected);
903 s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
904 if (s->s3->alpn_selected == NULL) {
905 *al = SSL_AD_INTERNAL_ERROR;
908 s->s3->alpn_selected_len = selected_len;
909 #ifndef OPENSSL_NO_NEXTPROTONEG
910 /* ALPN takes precedence over NPN. */
914 *al = SSL_AD_NO_APPLICATION_PROTOCOL;
922 static int init_sig_algs(SSL *s, unsigned int context)
924 /* Clear any signature algorithms extension received */
925 OPENSSL_free(s->s3->tmp.peer_sigalgs);
926 s->s3->tmp.peer_sigalgs = NULL;
931 #ifndef OPENSSL_NO_SRP
932 static int init_srp(SSL *s, unsigned int context)
934 OPENSSL_free(s->srp_ctx.login);
935 s->srp_ctx.login = NULL;
941 static int init_etm(SSL *s, unsigned int context)
948 static int init_ems(SSL *s, unsigned int context)
951 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
956 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
958 if (!s->server && s->hit) {
960 * Check extended master secret extension is consistent with
963 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
964 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
965 *al = SSL_AD_HANDSHAKE_FAILURE;
966 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
974 #ifndef OPENSSL_NO_SRTP
975 static int init_srtp(SSL *s, unsigned int context)
978 s->srtp_profile = NULL;
984 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
986 if (!sent && SSL_IS_TLS13(s)) {
987 *al = TLS13_AD_MISSING_EXTENSION;
988 SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
995 #ifndef OPENSSL_NO_EC
996 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
998 if (!SSL_IS_TLS13(s))
1005 * we have no key_share
1007 * (we are not resuming
1008 * OR the kex_mode doesn't allow non key_share resumes)
1015 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
1016 /* Nothing left we can do - just fail */
1017 *al = SSL_AD_HANDSHAKE_FAILURE;
1018 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1025 * we have no key_share
1028 * we didn't already send a HelloRetryRequest
1030 * the client sent a key_share extension
1032 * (we are not resuming
1033 * OR the kex_mode allows key_share resumes)
1035 * a shared group exists
1037 * send a HelloRetryRequest
1039 * we are not resuming
1041 * the kex_mode doesn't allow non key_share resumes
1045 if (s->server && s->s3->peer_tmp == NULL) {
1046 /* No suitable share */
1047 if (s->hello_retry_request == 0 && sent
1049 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1051 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1052 size_t num_curves, clnt_num_curves, i;
1053 unsigned int group_id = 0;
1055 /* Check if a shared group exists */
1057 /* Get the clients list of supported groups. */
1058 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1059 *al = SSL_AD_INTERNAL_ERROR;
1060 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1064 /* Get our list of available groups */
1065 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1066 *al = SSL_AD_INTERNAL_ERROR;
1067 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1071 /* Find the first group we allow that is also in client's list */
1072 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1073 i++, pcurvestmp += 2) {
1074 group_id = bytestogroup(pcurvestmp);
1076 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1080 if (i < num_curves) {
1081 /* A shared group exists so send a HelloRetryRequest */
1082 s->s3->group_id = group_id;
1083 s->hello_retry_request = 1;
1088 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1089 /* Nothing left we can do - just fail */
1090 *al = SSL_AD_HANDSHAKE_FAILURE;
1091 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1096 /* We have a key_share so don't send any more HelloRetryRequest messages */
1098 s->hello_retry_request = 0;
1101 * For a client side resumption with no key_share we need to generate
1102 * the handshake secret (otherwise this is done during key_share
1105 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1106 *al = SSL_AD_INTERNAL_ERROR;
1107 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1115 static int init_psk_kex_modes(SSL *s, unsigned int context)
1117 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1121 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1122 size_t binderoffset, const unsigned char *binderin,
1123 unsigned char *binderout,
1124 SSL_SESSION *sess, int sign)
1126 EVP_PKEY *mackey = NULL;
1127 EVP_MD_CTX *mctx = NULL;
1128 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1129 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1130 const char resumption_label[] = "resumption psk binder key";
1131 size_t bindersize, hashsize = EVP_MD_size(md);
1134 /* Generate the early_secret */
1135 if (!tls13_generate_secret(s, md, NULL, sess->master_key,
1136 sess->master_key_length,
1137 (unsigned char *)&s->early_secret)) {
1138 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1143 * Create the handshake hash for the binder key...the messages so far are
1146 mctx = EVP_MD_CTX_new();
1148 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1149 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1150 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1154 /* Generate the binder key */
1155 if (!tls13_hkdf_expand(s, md, s->early_secret,
1156 (unsigned char *)resumption_label,
1157 sizeof(resumption_label) - 1, hash, binderkey,
1159 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1163 /* Generate the finished key */
1164 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1165 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1169 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1170 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1175 * Get a hash of the ClientHello up to the start of the binders. If we are
1176 * following a HelloRetryRequest then this includes the hash of the first
1177 * ClientHello and the HelloRetryRequest itself.
1179 if (s->hello_retry_request) {
1183 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1184 if (hdatalen <= 0) {
1185 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1190 * For servers the handshake buffer data will include the second
1191 * ClientHello - which we don't want - so we need to take that bit off.
1194 if (hdatalen < s->init_num + SSL3_HM_HEADER_LENGTH) {
1195 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1198 hdatalen -= s->init_num + SSL3_HM_HEADER_LENGTH;
1201 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1202 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1207 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1208 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1209 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1213 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1214 if (mackey == NULL) {
1215 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1220 binderout = tmpbinder;
1222 bindersize = hashsize;
1223 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1224 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1225 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1226 || bindersize != hashsize) {
1227 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1234 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1235 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1239 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1240 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1241 EVP_PKEY_free(mackey);
1242 EVP_MD_CTX_free(mctx);
1247 static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
1249 if (!s->server || !sent)
1252 if (s->max_early_data == 0
1254 || s->session->ext.tick_identity != 0
1255 || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
1256 || !s->ext.early_data_ok
1257 || s->hello_retry_request
1258 || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
1259 || (s->s3->alpn_selected_len > 0
1260 && memcmp(s->s3->alpn_selected, s->session->ext.alpn_selected,
1261 s->s3->alpn_selected_len) != 0)) {
1262 s->ext.early_data = SSL_EARLY_DATA_REJECTED;
1264 s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1266 if (!tls13_change_cipher_state(s,
1267 SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
1268 *al = SSL_AD_INTERNAL_ERROR;