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
10 #include "../ssl_locl.h"
11 #include "statem_locl.h"
13 static int final_renegotiate(SSL *s, unsigned int context, int sent,
15 static int init_server_name(SSL *s, unsigned int context);
16 static int final_server_name(SSL *s, unsigned int context, int sent,
19 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
22 static int init_session_ticket(SSL *s, unsigned int context);
23 #ifndef OPENSSL_NO_OCSP
24 static int init_status_request(SSL *s, unsigned int context);
26 #ifndef OPENSSL_NO_NEXTPROTONEG
27 static int init_npn(SSL *s, unsigned int context);
29 static int init_alpn(SSL *s, unsigned int context);
30 static int final_alpn(SSL *s, unsigned int context, int sent, int *al);
31 static int init_sig_algs(SSL *s, unsigned int context);
32 #ifndef OPENSSL_NO_SRP
33 static int init_srp(SSL *s, unsigned int context);
35 static int init_etm(SSL *s, unsigned int context);
36 static int init_ems(SSL *s, unsigned int context);
37 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
38 static int init_psk_kex_modes(SSL *s, unsigned int context);
40 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
42 #ifndef OPENSSL_NO_SRTP
43 static int init_srtp(SSL *s, unsigned int context);
45 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
47 /* Structure to define a built-in extension */
48 typedef struct extensions_definition_st {
49 /* The defined type for the extension */
52 * The context that this extension applies to, e.g. what messages and
57 * Initialise extension before parsing. Always called for relevant contexts
58 * even if extension not present
60 int (*init)(SSL *s, unsigned int context);
61 /* Parse extension sent from client to server */
62 int (*parse_ctos)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
63 size_t chainidx, int *al);
64 /* Parse extension send from server to client */
65 int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
66 size_t chainidx, int *al);
67 /* Construct extension sent from server to client */
68 int (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
69 size_t chainidx, int *al);
70 /* Construct extension sent from client to server */
71 int (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
72 size_t chainidx, int *al);
74 * Finalise extension after parsing. Always called where an extensions was
75 * initialised even if the extension was not present. |sent| is set to 1 if
76 * the extension was seen, or 0 otherwise.
78 int (*final)(SSL *s, unsigned int context, int sent, int *al);
79 } EXTENSION_DEFINITION;
82 * Definitions of all built-in extensions. NOTE: Changes in the number or order
83 * of these extensions should be mirrored with equivalent changes to the
84 * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
85 * Each extension has an initialiser, a client and
86 * server side parser and a finaliser. The initialiser is called (if the
87 * extension is relevant to the given context) even if we did not see the
88 * extension in the message that we received. The parser functions are only
89 * called if we see the extension in the message. The finalisers are always
90 * called if the initialiser was called.
91 * There are also server and client side constructor functions which are always
92 * called during message construction if the extension is relevant for the
94 * The initialisation, parsing, finalisation and construction functions are
95 * always called in the order defined in this list. Some extensions may depend
96 * on others having been processed first, so the order of this list is
98 * The extension context is defined by a series of flags which specify which
99 * messages the extension is relevant to. These flags also specify whether the
100 * extension is relevant to a particular protocol or protocol version.
102 * TODO(TLS1.3): Make sure we have a test to check the consistency of these
104 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL }
105 static const EXTENSION_DEFINITION ext_defs[] = {
107 TLSEXT_TYPE_renegotiate,
108 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_SSL3_ALLOWED
109 | EXT_TLS1_2_AND_BELOW_ONLY,
110 NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
111 tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
115 TLSEXT_TYPE_server_name,
116 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
117 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
119 tls_parse_ctos_server_name, tls_parse_stoc_server_name,
120 tls_construct_stoc_server_name, tls_construct_ctos_server_name,
123 #ifndef OPENSSL_NO_SRP
126 EXT_CLIENT_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
127 init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
133 TLSEXT_TYPE_early_data_info,
134 EXT_TLS1_3_NEW_SESSION_TICKET,
135 NULL, NULL, tls_parse_stoc_early_data_info,
136 tls_construct_stoc_early_data_info, NULL, NULL
138 #ifndef OPENSSL_NO_EC
140 TLSEXT_TYPE_ec_point_formats,
141 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
142 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
143 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
147 TLSEXT_TYPE_supported_groups,
148 EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
149 NULL, tls_parse_ctos_supported_groups, NULL,
150 NULL /* TODO(TLS1.3): Need to add this */,
151 tls_construct_ctos_supported_groups, NULL
158 TLSEXT_TYPE_session_ticket,
159 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
160 init_session_ticket, tls_parse_ctos_session_ticket,
161 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
162 tls_construct_ctos_session_ticket, NULL
165 TLSEXT_TYPE_signature_algorithms,
167 init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
168 tls_construct_ctos_sig_algs, final_sig_algs
170 #ifndef OPENSSL_NO_OCSP
172 TLSEXT_TYPE_status_request,
173 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
174 | EXT_TLS1_3_CERTIFICATE,
175 init_status_request, tls_parse_ctos_status_request,
176 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
177 tls_construct_ctos_status_request, NULL
182 #ifndef OPENSSL_NO_NEXTPROTONEG
184 TLSEXT_TYPE_next_proto_neg,
185 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
186 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
187 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
194 * Must appear in this list after server_name so that finalisation
195 * happens after server_name callbacks
197 TLSEXT_TYPE_application_layer_protocol_negotiation,
198 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
199 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
200 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
201 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
203 #ifndef OPENSSL_NO_SRTP
205 TLSEXT_TYPE_use_srtp,
206 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
207 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS | EXT_DTLS_ONLY,
208 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
209 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
215 TLSEXT_TYPE_encrypt_then_mac,
216 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY | EXT_SSL3_ALLOWED,
217 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
218 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
220 #ifndef OPENSSL_NO_CT
222 TLSEXT_TYPE_signed_certificate_timestamp,
223 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
224 | EXT_TLS1_3_CERTIFICATE,
227 * No server side support for this, but can be provided by a custom
228 * extension. This is an exception to the rule that custom extensions
229 * cannot override built in ones.
231 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
237 TLSEXT_TYPE_extended_master_secret,
238 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
239 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
240 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
243 TLSEXT_TYPE_supported_versions,
244 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
246 /* Processed inline as part of version selection */
247 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
250 TLSEXT_TYPE_psk_kex_modes,
251 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
252 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
253 tls_construct_ctos_psk_kex_modes, NULL
255 #ifndef OPENSSL_NO_EC
258 * Must be in this list after supported_groups. We need that to have
259 * been parsed before we do this one.
261 TLSEXT_TYPE_key_share,
262 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO
263 | EXT_TLS1_3_HELLO_RETRY_REQUEST | EXT_TLS_IMPLEMENTATION_ONLY
265 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
266 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
272 * Special unsolicited ServerHello extension only used when
273 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
275 TLSEXT_TYPE_cryptopro_bug,
276 EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
277 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
280 /* Must be immediately before pre_shared_key */
281 /* TODO(TLS1.3): Fix me */
285 /* We send this, but don't read it */
286 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
289 /* Required by the TLSv1.3 spec to always be the last extension */
291 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO | EXT_TLS_IMPLEMENTATION_ONLY
293 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
294 tls_construct_ctos_psk, NULL
299 * Verify whether we are allowed to use the extension |type| in the current
300 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
301 * indicate the extension is not allowed. If returning 1 then |*found| is set to
302 * 1 if we found a definition for the extension, and |*idx| is set to its index
304 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
305 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
306 RAW_EXTENSION **found)
309 size_t builtin_num = OSSL_NELEM(ext_defs);
310 const EXTENSION_DEFINITION *thisext;
312 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
313 if (type == thisext->type) {
314 /* Check we're allowed to use this extension in this context */
315 if ((context & thisext->context) == 0)
318 if (SSL_IS_DTLS(s)) {
319 if ((thisext->context & EXT_TLS_ONLY) != 0)
321 } else if ((thisext->context & EXT_DTLS_ONLY) != 0) {
325 *found = &rawexlist[i];
330 if ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) == 0) {
332 * Custom extensions only apply to <=TLS1.2. This extension is unknown
333 * in this context - we allow it
339 /* Check the custom extensions */
341 for (i = builtin_num; i < builtin_num + meths->meths_count; i++) {
342 if (meths->meths[i - builtin_num].ext_type == type) {
343 *found = &rawexlist[i];
349 /* Unknown extension. We allow it */
355 * Check whether the context defined for an extension |extctx| means whether
356 * the extension is relevant for the current context |thisctx| or not. Returns
357 * 1 if the extension is relevant for this context, and 0 otherwise
359 static int extension_is_relevant(SSL *s, unsigned int extctx,
360 unsigned int thisctx)
363 && (extctx & EXT_TLS_IMPLEMENTATION_ONLY) != 0)
364 || (s->version == SSL3_VERSION
365 && (extctx & EXT_SSL3_ALLOWED) == 0)
367 && (extctx & EXT_TLS1_2_AND_BELOW_ONLY) != 0)
368 || (!SSL_IS_TLS13(s) && (extctx & EXT_TLS1_3_ONLY) != 0))
375 * Gather a list of all the extensions from the data in |packet]. |context|
376 * tells us which message this extension is for. The raw extension data is
377 * stored in |*res| on success. In the event of an error the alert type to use
378 * is stored in |*al|. We don't actually process the content of the extensions
379 * yet, except to check their types. This function also runs the initialiser
380 * functions for all known extensions (whether we have collected them or not).
381 * If successful the caller is responsible for freeing the contents of |*res|.
383 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
384 * more than one extension of the same type in a ClientHello or ServerHello.
385 * This function returns 1 if all extensions are unique and we have parsed their
386 * types, and 0 if the extensions contain duplicates, could not be successfully
387 * found, or an internal error occurred. We only check duplicates for
388 * extensions that we know about. We ignore others.
390 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
391 RAW_EXTENSION **res, int *al, size_t *len)
393 PACKET extensions = *packet;
396 custom_ext_methods *exts = NULL;
397 RAW_EXTENSION *raw_extensions = NULL;
398 const EXTENSION_DEFINITION *thisexd;
403 * Initialise server side custom extensions. Client side is done during
404 * construction of extensions for the ClientHello.
406 if ((context & EXT_CLIENT_HELLO) != 0) {
407 exts = &s->cert->srv_ext;
408 custom_ext_init(&s->cert->srv_ext);
409 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
410 exts = &s->cert->cli_ext;
413 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
414 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
415 if (raw_extensions == NULL) {
416 *al = SSL_AD_INTERNAL_ERROR;
417 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
421 while (PACKET_remaining(&extensions) > 0) {
424 RAW_EXTENSION *thisex;
426 if (!PACKET_get_net_2(&extensions, &type) ||
427 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
428 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
429 *al = SSL_AD_DECODE_ERROR;
433 * Verify this extension is allowed. We only check duplicates for
434 * extensions that we recognise.
436 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
437 || (thisex != NULL && thisex->present == 1)) {
438 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
439 *al = SSL_AD_ILLEGAL_PARAMETER;
442 if (thisex != NULL) {
443 thisex->data = extension;
450 * Initialise all known extensions relevant to this context, whether we have
453 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
454 if(thisexd->init != NULL && (thisexd->context & context) != 0
455 && extension_is_relevant(s, thisexd->context, context)
456 && !thisexd->init(s, context)) {
457 *al = SSL_AD_INTERNAL_ERROR;
462 *res = raw_extensions;
468 OPENSSL_free(raw_extensions);
473 * Runs the parser for a given extension with index |idx|. |exts| contains the
474 * list of all parsed extensions previously collected by
475 * tls_collect_extensions(). The parser is only run if it is applicable for the
476 * given |context| and the parser has not already been run. If this is for a
477 * Certificate message, then we also provide the parser with the relevant
478 * Certificate |x| and its position in the |chainidx| with 0 being the first
479 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
480 * |*al| is populated with a suitable alert code. If an extension is not present
481 * this counted as success.
483 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
484 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
486 RAW_EXTENSION *currext = &exts[idx];
487 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
488 size_t chainidx, int *al) = NULL;
490 /* Skip if the extension is not present */
491 if (!currext->present)
495 s->ext.debug_cb(s, !s->server, currext->type,
496 PACKET_data(&currext->data),
497 PACKET_remaining(&currext->data),
500 /* Skip if we've already parsed this extension */
506 if (idx < OSSL_NELEM(ext_defs)) {
507 /* We are handling a built-in extension */
508 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
510 /* Check if extension is defined for our protocol. If not, skip */
511 if (!extension_is_relevant(s, extdef->context, context))
514 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
517 return parser(s, &currext->data, context, x, chainidx, al);
520 * If the parser is NULL we fall through to the custom extension
526 * This is a custom extension. We only allow this if it is a non
527 * resumed session on the server side.
529 * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
530 * We're going to need a new mechanism for TLS1.3 to specify which
531 * messages to add the custom extensions to.
533 if ((!s->hit || !s->server)
535 & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
536 && custom_ext_parse(s, s->server, currext->type,
537 PACKET_data(&currext->data),
538 PACKET_remaining(&currext->data),
546 * Parse all remaining extensions that have not yet been parsed. Also calls the
547 * finalisation for all extensions at the end, whether we collected them or not.
548 * Returns 1 for success or 0 for failure. If we are working on a Certificate
549 * message then we also pass the Certificate |x| and its position in the
550 * |chainidx|, with 0 being the first certificate. On failure, |*al| is
551 * populated with a suitable alert code.
553 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
554 size_t chainidx, int *al)
556 size_t i, numexts = OSSL_NELEM(ext_defs);
557 const EXTENSION_DEFINITION *thisexd;
559 /* Calculate the number of extensions in the extensions list */
560 if ((context & EXT_CLIENT_HELLO) != 0) {
561 numexts += s->cert->srv_ext.meths_count;
562 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
563 numexts += s->cert->cli_ext.meths_count;
566 /* Parse each extension in turn */
567 for (i = 0; i < numexts; i++) {
568 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
573 * Finalise all known extensions relevant to this context, whether we have
576 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
577 if(thisexd->final != NULL
578 && (thisexd->context & context) != 0
579 && !thisexd->final(s, context, exts[i].present, al))
587 * Construct all the extensions relevant to the current |context| and write
588 * them to |pkt|. If this is an extension for a Certificate in a Certificate
589 * message, then |x| will be set to the Certificate we are handling, and
590 * |chainidx| will indicate the position in the chainidx we are processing (with
591 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
592 * failure occurs then |al| is populated with a suitable alert code. On a
593 * failure construction stops at the first extension to fail to construct.
595 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
596 X509 *x, size_t chainidx, int *al)
599 int addcustom = 0, min_version, max_version = 0, reason, tmpal;
600 const EXTENSION_DEFINITION *thisexd;
603 * Normally if something goes wrong during construction it's an internal
604 * error. We can always override this later.
606 tmpal = SSL_AD_INTERNAL_ERROR;
608 if (!WPACKET_start_sub_packet_u16(pkt)
610 * If extensions are of zero length then we don't even add the
611 * extensions length bytes to a ClientHello/ServerHello in SSLv3
613 || ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
614 && s->version == SSL3_VERSION
615 && !WPACKET_set_flags(pkt,
616 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
617 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
621 if ((context & EXT_CLIENT_HELLO) != 0) {
622 reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
624 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
629 /* Add custom extensions first */
630 if ((context & EXT_CLIENT_HELLO) != 0) {
631 custom_ext_init(&s->cert->cli_ext);
633 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
635 * We already initialised the custom extensions during ClientHello
638 * TODO(TLS1.3): We're going to need a new custom extension mechanism
639 * for TLS1.3, so that custom extensions can specify which of the
640 * multiple message they wish to add themselves to.
645 if (addcustom && !custom_ext_add(s, s->server, pkt, &tmpal)) {
646 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
650 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
651 int (*construct)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
652 size_t chainidx, int *al);
654 /* Skip if not relevant for our context */
655 if ((thisexd->context & context) == 0)
658 construct = s->server ? thisexd->construct_stoc
659 : thisexd->construct_ctos;
661 /* Check if this extension is defined for our protocol. If not, skip */
663 && (thisexd->context & EXT_TLS_IMPLEMENTATION_ONLY)
665 || (s->version == SSL3_VERSION
666 && (thisexd->context & EXT_SSL3_ALLOWED) == 0)
668 && (thisexd->context & EXT_TLS1_2_AND_BELOW_ONLY)
671 && (thisexd->context & EXT_TLS1_3_ONLY) != 0
672 && (context & EXT_CLIENT_HELLO) == 0)
673 || ((thisexd->context & EXT_TLS1_3_ONLY) != 0
674 && (context & EXT_CLIENT_HELLO) != 0
675 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
676 || construct == NULL)
679 if (!construct(s, pkt, context, x, chainidx, &tmpal))
683 if (!WPACKET_close(pkt)) {
684 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
696 * Built in extension finalisation and initialisation functions. All initialise
697 * or finalise the associated extension type for the given |context|. For
698 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
699 * otherwise. These functions return 1 on success or 0 on failure. In the event
700 * of a failure then |*al| is populated with a suitable error code.
703 static int final_renegotiate(SSL *s, unsigned int context, int sent,
708 * Check if we can connect to a server that doesn't support safe
711 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
712 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
714 *al = SSL_AD_HANDSHAKE_FAILURE;
715 SSLerr(SSL_F_FINAL_RENEGOTIATE,
716 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
723 /* Need RI if renegotiating */
725 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
727 *al = SSL_AD_HANDSHAKE_FAILURE;
728 SSLerr(SSL_F_FINAL_RENEGOTIATE,
729 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
737 static int init_server_name(SSL *s, unsigned int context)
740 s->servername_done = 0;
745 static int final_server_name(SSL *s, unsigned int context, int sent,
748 int ret = SSL_TLSEXT_ERR_NOACK;
749 int altmp = SSL_AD_UNRECOGNIZED_NAME;
751 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
752 ret = s->ctx->ext.servername_cb(s, &altmp,
753 s->ctx->ext.servername_arg);
754 else if (s->session_ctx != NULL
755 && s->session_ctx->ext.servername_cb != 0)
756 ret = s->session_ctx->ext.servername_cb(s, &altmp,
757 s->session_ctx->ext.servername_arg);
760 case SSL_TLSEXT_ERR_ALERT_FATAL:
764 case SSL_TLSEXT_ERR_ALERT_WARNING:
768 case SSL_TLSEXT_ERR_NOACK:
769 s->servername_done = 0;
777 #ifndef OPENSSL_NO_EC
778 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
781 unsigned long alg_k, alg_a;
786 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
787 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
790 * If we are client and using an elliptic curve cryptography cipher
791 * suite, then if server returns an EC point formats lists extension it
792 * must contain uncompressed.
794 if (s->ext.ecpointformats != NULL
795 && s->ext.ecpointformats_len > 0
796 && s->session->ext.ecpointformats != NULL
797 && s->session->ext.ecpointformats_len > 0
798 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
799 /* we are using an ECC cipher */
801 unsigned char *list = s->session->ext.ecpointformats;
803 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
804 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
807 if (i == s->session->ext.ecpointformats_len) {
808 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
809 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
818 static int init_session_ticket(SSL *s, unsigned int context)
821 s->ext.ticket_expected = 0;
826 #ifndef OPENSSL_NO_OCSP
827 static int init_status_request(SSL *s, unsigned int context)
830 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
833 * Ensure we get sensible values passed to tlsext_status_cb in the event
834 * that we don't receive a status message
836 OPENSSL_free(s->ext.ocsp.resp);
837 s->ext.ocsp.resp = NULL;
838 s->ext.ocsp.resp_len = 0;
845 #ifndef OPENSSL_NO_NEXTPROTONEG
846 static int init_npn(SSL *s, unsigned int context)
854 static int init_alpn(SSL *s, unsigned int context)
856 OPENSSL_free(s->s3->alpn_selected);
857 s->s3->alpn_selected = NULL;
859 s->s3->alpn_selected_len = 0;
860 OPENSSL_free(s->s3->alpn_proposed);
861 s->s3->alpn_proposed = NULL;
862 s->s3->alpn_proposed_len = 0;
867 static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
869 const unsigned char *selected = NULL;
870 unsigned char selected_len = 0;
875 if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
876 int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
877 s->s3->alpn_proposed,
878 (unsigned int)s->s3->alpn_proposed_len,
879 s->ctx->ext.alpn_select_cb_arg);
881 if (r == SSL_TLSEXT_ERR_OK) {
882 OPENSSL_free(s->s3->alpn_selected);
883 s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
884 if (s->s3->alpn_selected == NULL) {
885 *al = SSL_AD_INTERNAL_ERROR;
888 s->s3->alpn_selected_len = selected_len;
889 #ifndef OPENSSL_NO_NEXTPROTONEG
890 /* ALPN takes precedence over NPN. */
894 *al = SSL_AD_NO_APPLICATION_PROTOCOL;
902 static int init_sig_algs(SSL *s, unsigned int context)
904 /* Clear any signature algorithms extension received */
905 OPENSSL_free(s->s3->tmp.peer_sigalgs);
906 s->s3->tmp.peer_sigalgs = NULL;
911 #ifndef OPENSSL_NO_SRP
912 static int init_srp(SSL *s, unsigned int context)
914 OPENSSL_free(s->srp_ctx.login);
915 s->srp_ctx.login = NULL;
921 static int init_etm(SSL *s, unsigned int context)
928 static int init_ems(SSL *s, unsigned int context)
931 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
936 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
938 if (!s->server && s->hit) {
940 * Check extended master secret extension is consistent with
943 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
944 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
945 *al = SSL_AD_HANDSHAKE_FAILURE;
946 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
954 #ifndef OPENSSL_NO_SRTP
955 static int init_srtp(SSL *s, unsigned int context)
958 s->srtp_profile = NULL;
964 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
966 if (!sent && SSL_IS_TLS13(s)) {
967 *al = TLS13_AD_MISSING_EXTENSION;
968 SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
975 #ifndef OPENSSL_NO_EC
976 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
978 if (!SSL_IS_TLS13(s))
985 * we have no key_share
987 * (we are not resuming
988 * OR the kex_mode doesn't allow non key_share resumes)
995 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
996 /* Nothing left we can do - just fail */
997 *al = SSL_AD_HANDSHAKE_FAILURE;
998 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1005 * we have no key_share
1008 * we didn't already send a HelloRetryRequest
1010 * the client sent a key_share extension
1012 * (we are not resuming
1013 * OR the kex_mode allows key_share resumes)
1015 * a shared group exists
1017 * send a HelloRetryRequest
1019 * we are not resuming
1021 * the kex_mode doesn't allow non key_share resumes
1025 if (s->server && s->s3->peer_tmp == NULL) {
1026 /* No suitable share */
1027 if (s->hello_retry_request == 0 && sent
1029 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1031 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1032 size_t num_curves, clnt_num_curves, i;
1033 unsigned int group_id = 0;
1035 /* Check if a shared group exists */
1037 /* Get the clients list of supported groups. */
1038 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1039 *al = SSL_AD_INTERNAL_ERROR;
1040 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1044 /* Get our list of available groups */
1045 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1046 *al = SSL_AD_INTERNAL_ERROR;
1047 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1051 /* Find the first group we allow that is also in client's list */
1052 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1053 i++, pcurvestmp += 2) {
1054 group_id = bytestogroup(pcurvestmp);
1056 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1060 if (i < num_curves) {
1061 /* A shared group exists so send a HelloRetryRequest */
1062 s->s3->group_id = group_id;
1063 s->hello_retry_request = 1;
1068 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1069 /* Nothing left we can do - just fail */
1070 *al = SSL_AD_HANDSHAKE_FAILURE;
1071 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1076 /* We have a key_share so don't send any more HelloRetryRequest messages */
1078 s->hello_retry_request = 0;
1081 * For a client side resumption with no key_share we need to generate
1082 * the handshake secret (otherwise this is done during key_share
1085 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1086 *al = SSL_AD_INTERNAL_ERROR;
1087 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1095 static int init_psk_kex_modes(SSL *s, unsigned int context)
1097 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1101 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1102 size_t binderoffset, const unsigned char *binderin,
1103 unsigned char *binderout,
1104 SSL_SESSION *sess, int sign)
1106 EVP_PKEY *mackey = NULL;
1107 EVP_MD_CTX *mctx = NULL;
1108 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1109 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1110 const char resumption_label[] = "resumption psk binder key";
1111 size_t bindersize, hashsize = EVP_MD_size(md);
1114 /* Generate the early_secret */
1115 if (!tls13_generate_secret(s, md, NULL, sess->master_key,
1116 sess->master_key_length,
1117 (unsigned char *)&s->early_secret)) {
1118 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1123 * Create the handshake hash for the binder key...the messages so far are
1126 mctx = EVP_MD_CTX_new();
1128 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1129 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1130 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1134 /* Generate the binder key */
1135 if (!tls13_hkdf_expand(s, md, s->early_secret,
1136 (unsigned char *)resumption_label,
1137 sizeof(resumption_label) - 1, hash, binderkey,
1139 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1143 /* Generate the finished key */
1144 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1145 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1149 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1150 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1155 * Get a hash of the ClientHello up to the start of the binders. If we are
1156 * following a HelloRetryRequest then this includes the hash of the first
1157 * ClientHello and the HelloRetryRequest itself.
1159 if (s->hello_retry_request) {
1163 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1164 if (hdatalen <= 0) {
1165 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1170 * For servers the handshake buffer data will include the second
1171 * ClientHello - which we don't want - so we need to take that bit off.
1174 if (hdatalen < s->init_num + SSL3_HM_HEADER_LENGTH) {
1175 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1178 hdatalen -= s->init_num + SSL3_HM_HEADER_LENGTH;
1181 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1182 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1187 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1188 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1189 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1193 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1194 if (mackey == NULL) {
1195 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1200 binderout = tmpbinder;
1202 bindersize = hashsize;
1203 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1204 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1205 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1206 || bindersize != hashsize) {
1207 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1214 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1215 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1219 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1220 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1221 EVP_PKEY_free(mackey);
1222 EVP_MD_CTX_free(mctx);