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
132 #ifndef OPENSSL_NO_EC
134 TLSEXT_TYPE_ec_point_formats,
135 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
136 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
137 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
141 TLSEXT_TYPE_supported_groups,
142 EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
143 NULL, tls_parse_ctos_supported_groups, NULL,
144 NULL /* TODO(TLS1.3): Need to add this */,
145 tls_construct_ctos_supported_groups, NULL
152 TLSEXT_TYPE_session_ticket,
153 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
154 init_session_ticket, tls_parse_ctos_session_ticket,
155 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
156 tls_construct_ctos_session_ticket, NULL
159 TLSEXT_TYPE_signature_algorithms,
161 init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
162 tls_construct_ctos_sig_algs, final_sig_algs
164 #ifndef OPENSSL_NO_OCSP
166 TLSEXT_TYPE_status_request,
167 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
168 | EXT_TLS1_3_CERTIFICATE,
169 init_status_request, tls_parse_ctos_status_request,
170 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
171 tls_construct_ctos_status_request, NULL
176 #ifndef OPENSSL_NO_NEXTPROTONEG
178 TLSEXT_TYPE_next_proto_neg,
179 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
180 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
181 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
188 * Must appear in this list after server_name so that finalisation
189 * happens after server_name callbacks
191 TLSEXT_TYPE_application_layer_protocol_negotiation,
192 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
193 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
194 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
195 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
197 #ifndef OPENSSL_NO_SRTP
199 TLSEXT_TYPE_use_srtp,
200 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
201 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS | EXT_DTLS_ONLY,
202 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
203 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
209 TLSEXT_TYPE_encrypt_then_mac,
210 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
211 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
212 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
214 #ifndef OPENSSL_NO_CT
216 TLSEXT_TYPE_signed_certificate_timestamp,
217 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
218 | EXT_TLS1_3_CERTIFICATE,
221 * No server side support for this, but can be provided by a custom
222 * extension. This is an exception to the rule that custom extensions
223 * cannot override built in ones.
225 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
231 TLSEXT_TYPE_extended_master_secret,
232 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
233 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
234 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
237 TLSEXT_TYPE_supported_versions,
238 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
240 /* Processed inline as part of version selection */
241 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
244 TLSEXT_TYPE_psk_kex_modes,
245 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
246 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
247 tls_construct_ctos_psk_kex_modes, NULL
249 #ifndef OPENSSL_NO_EC
252 * Must be in this list after supported_groups. We need that to have
253 * been parsed before we do this one.
255 TLSEXT_TYPE_key_share,
256 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO
257 | EXT_TLS1_3_HELLO_RETRY_REQUEST | EXT_TLS_IMPLEMENTATION_ONLY
259 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
260 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
266 * Special unsolicited ServerHello extension only used when
267 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
269 TLSEXT_TYPE_cryptopro_bug,
270 EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
271 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
274 /* Must be immediately before pre_shared_key */
275 /* TODO(TLS1.3): Fix me */
279 /* We send this, but don't read it */
280 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
283 /* Required by the TLSv1.3 spec to always be the last extension */
285 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO | EXT_TLS_IMPLEMENTATION_ONLY
287 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
288 tls_construct_ctos_psk, NULL
293 * Verify whether we are allowed to use the extension |type| in the current
294 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
295 * indicate the extension is not allowed. If returning 1 then |*found| is set to
296 * 1 if we found a definition for the extension, and |*idx| is set to its index
298 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
299 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
300 RAW_EXTENSION **found)
303 size_t builtin_num = OSSL_NELEM(ext_defs);
304 const EXTENSION_DEFINITION *thisext;
306 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
307 if (type == thisext->type) {
308 /* Check we're allowed to use this extension in this context */
309 if ((context & thisext->context) == 0)
312 if (SSL_IS_DTLS(s)) {
313 if ((thisext->context & EXT_TLS_ONLY) != 0)
315 } else if ((thisext->context & EXT_DTLS_ONLY) != 0) {
319 *found = &rawexlist[i];
324 if ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) == 0) {
326 * Custom extensions only apply to <=TLS1.2. This extension is unknown
327 * in this context - we allow it
333 /* Check the custom extensions */
335 for (i = builtin_num; i < builtin_num + meths->meths_count; i++) {
336 if (meths->meths[i - builtin_num].ext_type == type) {
337 *found = &rawexlist[i];
343 /* Unknown extension. We allow it */
349 * Check whether the context defined for an extension |extctx| means whether
350 * the extension is relevant for the current context |thisctx| or not. Returns
351 * 1 if the extension is relevant for this context, and 0 otherwise
353 static int extension_is_relevant(SSL *s, unsigned int extctx,
354 unsigned int thisctx)
357 && (extctx & EXT_TLS_IMPLEMENTATION_ONLY) != 0)
358 || (s->version == SSL3_VERSION
359 && (extctx & EXT_SSL3_ALLOWED) == 0)
361 && (extctx & EXT_TLS1_2_AND_BELOW_ONLY) != 0)
362 || (!SSL_IS_TLS13(s) && (extctx & EXT_TLS1_3_ONLY) != 0))
369 * Gather a list of all the extensions from the data in |packet]. |context|
370 * tells us which message this extension is for. The raw extension data is
371 * stored in |*res| on success. In the event of an error the alert type to use
372 * is stored in |*al|. We don't actually process the content of the extensions
373 * yet, except to check their types. This function also runs the initialiser
374 * functions for all known extensions (whether we have collected them or not).
375 * If successful the caller is responsible for freeing the contents of |*res|.
377 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
378 * more than one extension of the same type in a ClientHello or ServerHello.
379 * This function returns 1 if all extensions are unique and we have parsed their
380 * types, and 0 if the extensions contain duplicates, could not be successfully
381 * found, or an internal error occurred. We only check duplicates for
382 * extensions that we know about. We ignore others.
384 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
385 RAW_EXTENSION **res, int *al)
387 PACKET extensions = *packet;
389 custom_ext_methods *exts = NULL;
390 RAW_EXTENSION *raw_extensions = NULL;
391 const EXTENSION_DEFINITION *thisexd;
396 * Initialise server side custom extensions. Client side is done during
397 * construction of extensions for the ClientHello.
399 if ((context & EXT_CLIENT_HELLO) != 0) {
400 exts = &s->cert->srv_ext;
401 custom_ext_init(&s->cert->srv_ext);
402 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
403 exts = &s->cert->cli_ext;
406 raw_extensions = OPENSSL_zalloc((OSSL_NELEM(ext_defs)
407 + (exts != NULL ? exts->meths_count : 0))
408 * sizeof(*raw_extensions));
409 if (raw_extensions == NULL) {
410 *al = SSL_AD_INTERNAL_ERROR;
411 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
415 while (PACKET_remaining(&extensions) > 0) {
418 RAW_EXTENSION *thisex;
420 if (!PACKET_get_net_2(&extensions, &type) ||
421 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
422 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
423 *al = SSL_AD_DECODE_ERROR;
427 * Verify this extension is allowed. We only check duplicates for
428 * extensions that we recognise.
430 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
431 || (thisex != NULL && thisex->present == 1)) {
432 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
433 *al = SSL_AD_ILLEGAL_PARAMETER;
436 if (thisex != NULL) {
437 thisex->data = extension;
444 * Initialise all known extensions relevant to this context, whether we have
447 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
448 if(thisexd->init != NULL && (thisexd->context & context) != 0
449 && extension_is_relevant(s, thisexd->context, context)
450 && !thisexd->init(s, context)) {
451 *al = SSL_AD_INTERNAL_ERROR;
456 *res = raw_extensions;
460 OPENSSL_free(raw_extensions);
465 * Runs the parser for a given extension with index |idx|. |exts| contains the
466 * list of all parsed extensions previously collected by
467 * tls_collect_extensions(). The parser is only run if it is applicable for the
468 * given |context| and the parser has not already been run. If this is for a
469 * Certificate message, then we also provide the parser with the relevant
470 * Certificate |x| and its position in the |chainidx| with 0 being the first
471 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
472 * |*al| is populated with a suitable alert code. If an extension is not present
473 * this counted as success.
475 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
476 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
478 RAW_EXTENSION *currext = &exts[idx];
479 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
480 size_t chainidx, int *al) = NULL;
482 /* Skip if the extension is not present */
483 if (!currext->present)
487 s->ext.debug_cb(s, !s->server, currext->type,
488 PACKET_data(&currext->data),
489 PACKET_remaining(&currext->data),
492 /* Skip if we've already parsed this extension */
498 if (idx < OSSL_NELEM(ext_defs)) {
499 /* We are handling a built-in extension */
500 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
502 /* Check if extension is defined for our protocol. If not, skip */
503 if (!extension_is_relevant(s, extdef->context, context))
506 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
509 return parser(s, &currext->data, context, x, chainidx, al);
512 * If the parser is NULL we fall through to the custom extension
518 * This is a custom extension. We only allow this if it is a non
519 * resumed session on the server side.
521 * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
522 * We're going to need a new mechanism for TLS1.3 to specify which
523 * messages to add the custom extensions to.
525 if ((!s->hit || !s->server)
527 & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
528 && custom_ext_parse(s, s->server, currext->type,
529 PACKET_data(&currext->data),
530 PACKET_remaining(&currext->data),
538 * Parse all remaining extensions that have not yet been parsed. Also calls the
539 * finalisation for all extensions at the end, whether we collected them or not.
540 * Returns 1 for success or 0 for failure. If we are working on a Certificate
541 * message then we also pass the Certificate |x| and its position in the
542 * |chainidx|, with 0 being the first certificate. On failure, |*al| is
543 * populated with a suitable alert code.
545 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
546 size_t chainidx, int *al)
548 size_t i, numexts = OSSL_NELEM(ext_defs);
549 const EXTENSION_DEFINITION *thisexd;
551 /* Calculate the number of extensions in the extensions list */
552 if ((context & EXT_CLIENT_HELLO) != 0) {
553 numexts += s->cert->srv_ext.meths_count;
554 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
555 numexts += s->cert->cli_ext.meths_count;
558 /* Parse each extension in turn */
559 for (i = 0; i < numexts; i++) {
560 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
565 * Finalise all known extensions relevant to this context, whether we have
568 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
569 if(thisexd->final != NULL
570 && (thisexd->context & context) != 0
571 && !thisexd->final(s, context, exts[i].present, al))
579 * Construct all the extensions relevant to the current |context| and write
580 * them to |pkt|. If this is an extension for a Certificate in a Certificate
581 * message, then |x| will be set to the Certificate we are handling, and
582 * |chainidx| will indicate the position in the chainidx we are processing (with
583 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
584 * failure occurs then |al| is populated with a suitable alert code. On a
585 * failure construction stops at the first extension to fail to construct.
587 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
588 X509 *x, size_t chainidx, int *al)
591 int addcustom = 0, min_version, max_version = 0, reason, tmpal;
592 const EXTENSION_DEFINITION *thisexd;
595 * Normally if something goes wrong during construction it's an internal
596 * error. We can always override this later.
598 tmpal = SSL_AD_INTERNAL_ERROR;
600 if (!WPACKET_start_sub_packet_u16(pkt)
602 * If extensions are of zero length then we don't even add the
603 * extensions length bytes to a ClientHello/ServerHello in SSLv3
605 || ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
606 && s->version == SSL3_VERSION
607 && !WPACKET_set_flags(pkt,
608 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
609 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
613 if ((context & EXT_CLIENT_HELLO) != 0) {
614 reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
616 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
621 /* Add custom extensions first */
622 if ((context & EXT_CLIENT_HELLO) != 0) {
623 custom_ext_init(&s->cert->cli_ext);
625 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
627 * We already initialised the custom extensions during ClientHello
630 * TODO(TLS1.3): We're going to need a new custom extension mechanism
631 * for TLS1.3, so that custom extensions can specify which of the
632 * multiple message they wish to add themselves to.
637 if (addcustom && !custom_ext_add(s, s->server, pkt, &tmpal)) {
638 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
642 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
643 int (*construct)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
644 size_t chainidx, int *al);
646 /* Skip if not relevant for our context */
647 if ((thisexd->context & context) == 0)
650 construct = s->server ? thisexd->construct_stoc
651 : thisexd->construct_ctos;
653 /* Check if this extension is defined for our protocol. If not, skip */
655 && (thisexd->context & EXT_TLS_IMPLEMENTATION_ONLY)
657 || (s->version == SSL3_VERSION
658 && (thisexd->context & EXT_SSL3_ALLOWED) == 0)
660 && (thisexd->context & EXT_TLS1_2_AND_BELOW_ONLY)
663 && (thisexd->context & EXT_TLS1_3_ONLY) != 0
664 && (context & EXT_CLIENT_HELLO) == 0)
665 || ((thisexd->context & EXT_TLS1_3_ONLY) != 0
666 && (context & EXT_CLIENT_HELLO) != 0
667 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
668 || construct == NULL)
671 if (!construct(s, pkt, context, x, chainidx, &tmpal))
675 if (!WPACKET_close(pkt)) {
676 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
688 * Built in extension finalisation and initialisation functions. All initialise
689 * or finalise the associated extension type for the given |context|. For
690 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
691 * otherwise. These functions return 1 on success or 0 on failure. In the event
692 * of a failure then |*al| is populated with a suitable error code.
695 static int final_renegotiate(SSL *s, unsigned int context, int sent,
700 * Check if we can connect to a server that doesn't support safe
703 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
704 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
706 *al = SSL_AD_HANDSHAKE_FAILURE;
707 SSLerr(SSL_F_FINAL_RENEGOTIATE,
708 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
715 /* Need RI if renegotiating */
717 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
719 *al = SSL_AD_HANDSHAKE_FAILURE;
720 SSLerr(SSL_F_FINAL_RENEGOTIATE,
721 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
729 static int init_server_name(SSL *s, unsigned int context)
732 s->servername_done = 0;
737 static int final_server_name(SSL *s, unsigned int context, int sent,
740 int ret = SSL_TLSEXT_ERR_NOACK;
741 int altmp = SSL_AD_UNRECOGNIZED_NAME;
743 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
744 ret = s->ctx->ext.servername_cb(s, &altmp,
745 s->ctx->ext.servername_arg);
746 else if (s->session_ctx != NULL
747 && s->session_ctx->ext.servername_cb != 0)
748 ret = s->session_ctx->ext.servername_cb(s, &altmp,
749 s->session_ctx->ext.servername_arg);
752 case SSL_TLSEXT_ERR_ALERT_FATAL:
756 case SSL_TLSEXT_ERR_ALERT_WARNING:
760 case SSL_TLSEXT_ERR_NOACK:
761 s->servername_done = 0;
769 #ifndef OPENSSL_NO_EC
770 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
773 unsigned long alg_k, alg_a;
778 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
779 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
782 * If we are client and using an elliptic curve cryptography cipher
783 * suite, then if server returns an EC point formats lists extension it
784 * must contain uncompressed.
786 if (s->ext.ecpointformats != NULL
787 && s->ext.ecpointformats_len > 0
788 && s->session->ext.ecpointformats != NULL
789 && s->session->ext.ecpointformats_len > 0
790 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
791 /* we are using an ECC cipher */
793 unsigned char *list = s->session->ext.ecpointformats;
795 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
796 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
799 if (i == s->session->ext.ecpointformats_len) {
800 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
801 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
810 static int init_session_ticket(SSL *s, unsigned int context)
813 s->ext.ticket_expected = 0;
818 #ifndef OPENSSL_NO_OCSP
819 static int init_status_request(SSL *s, unsigned int context)
822 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
825 * Ensure we get sensible values passed to tlsext_status_cb in the event
826 * that we don't receive a status message
828 OPENSSL_free(s->ext.ocsp.resp);
829 s->ext.ocsp.resp = NULL;
830 s->ext.ocsp.resp_len = 0;
837 #ifndef OPENSSL_NO_NEXTPROTONEG
838 static int init_npn(SSL *s, unsigned int context)
846 static int init_alpn(SSL *s, unsigned int context)
848 OPENSSL_free(s->s3->alpn_selected);
849 s->s3->alpn_selected = NULL;
851 s->s3->alpn_selected_len = 0;
852 OPENSSL_free(s->s3->alpn_proposed);
853 s->s3->alpn_proposed = NULL;
854 s->s3->alpn_proposed_len = 0;
859 static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
861 const unsigned char *selected = NULL;
862 unsigned char selected_len = 0;
867 if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
868 int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
869 s->s3->alpn_proposed,
870 (unsigned int)s->s3->alpn_proposed_len,
871 s->ctx->ext.alpn_select_cb_arg);
873 if (r == SSL_TLSEXT_ERR_OK) {
874 OPENSSL_free(s->s3->alpn_selected);
875 s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
876 if (s->s3->alpn_selected == NULL) {
877 *al = SSL_AD_INTERNAL_ERROR;
880 s->s3->alpn_selected_len = selected_len;
881 #ifndef OPENSSL_NO_NEXTPROTONEG
882 /* ALPN takes precedence over NPN. */
886 *al = SSL_AD_NO_APPLICATION_PROTOCOL;
894 static int init_sig_algs(SSL *s, unsigned int context)
896 /* Clear any signature algorithms extension received */
897 OPENSSL_free(s->s3->tmp.peer_sigalgs);
898 s->s3->tmp.peer_sigalgs = NULL;
903 #ifndef OPENSSL_NO_SRP
904 static int init_srp(SSL *s, unsigned int context)
906 OPENSSL_free(s->srp_ctx.login);
907 s->srp_ctx.login = NULL;
913 static int init_etm(SSL *s, unsigned int context)
915 s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC;
920 static int init_ems(SSL *s, unsigned int context)
923 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
928 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
930 if (!s->server && s->hit) {
932 * Check extended master secret extension is consistent with
935 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
936 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
937 *al = SSL_AD_HANDSHAKE_FAILURE;
938 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
946 #ifndef OPENSSL_NO_SRTP
947 static int init_srtp(SSL *s, unsigned int context)
950 s->srtp_profile = NULL;
956 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
958 if (!sent && SSL_IS_TLS13(s)) {
959 *al = TLS13_AD_MISSING_EXTENSION;
960 SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
967 #ifndef OPENSSL_NO_EC
968 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
970 if (!SSL_IS_TLS13(s))
977 * we have no key_share
979 * (we are not resuming
980 * OR the kex_mode doesn't allow non key_share resumes)
987 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
988 /* Nothing left we can do - just fail */
989 *al = SSL_AD_HANDSHAKE_FAILURE;
990 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
997 * we have no key_share
1000 * we didn't already send a HelloRetryRequest
1002 * the client sent a key_share extension
1004 * (we are not resuming
1005 * OR the kex_mode allows key_share resumes)
1007 * a shared group exists
1009 * send a HelloRetryRequest
1011 * we are not resuming
1013 * the kex_mode doesn't allow non key_share resumes
1017 if (s->server && s->s3->peer_tmp == NULL) {
1018 /* No suitable share */
1019 if (s->hello_retry_request == 0 && sent
1021 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1023 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1024 size_t num_curves, clnt_num_curves, i;
1025 unsigned int group_id = 0;
1027 /* Check if a shared group exists */
1029 /* Get the clients list of supported groups. */
1030 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1031 *al = SSL_AD_INTERNAL_ERROR;
1032 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1036 /* Get our list of available groups */
1037 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1038 *al = SSL_AD_INTERNAL_ERROR;
1039 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1043 /* Find the first group we allow that is also in client's list */
1044 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1045 i++, pcurvestmp += 2) {
1046 group_id = bytestogroup(pcurvestmp);
1048 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1052 if (i < num_curves) {
1053 /* A shared group exists so send a HelloRetryRequest */
1054 s->s3->group_id = group_id;
1055 s->hello_retry_request = 1;
1060 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1061 /* Nothing left we can do - just fail */
1062 *al = SSL_AD_HANDSHAKE_FAILURE;
1063 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1068 /* We have a key_share so don't send any more HelloRetryRequest messages */
1070 s->hello_retry_request = 0;
1073 * For a client side resumption with no key_share we need to generate
1074 * the handshake secret (otherwise this is done during key_share
1077 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1078 *al = SSL_AD_INTERNAL_ERROR;
1079 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1087 static int init_psk_kex_modes(SSL *s, unsigned int context)
1089 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1093 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1094 size_t binderoffset, const unsigned char *binderin,
1095 unsigned char *binderout,
1096 SSL_SESSION *sess, int sign)
1098 EVP_PKEY *mackey = NULL;
1099 EVP_MD_CTX *mctx = NULL;
1100 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1101 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1102 const char resumption_label[] = "resumption psk binder key";
1103 size_t bindersize, hashsize = EVP_MD_size(md);
1106 /* Generate the early_secret */
1107 if (!tls13_generate_secret(s, md, NULL, sess->master_key,
1108 sess->master_key_length,
1109 (unsigned char *)&s->early_secret)) {
1110 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1115 * Create the handshake hash for the binder key...the messages so far are
1118 mctx = EVP_MD_CTX_new();
1120 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1121 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1122 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1126 /* Generate the binder key */
1127 if (!tls13_hkdf_expand(s, md, s->early_secret,
1128 (unsigned char *)resumption_label,
1129 sizeof(resumption_label) - 1, hash, binderkey,
1131 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1135 /* Generate the finished key */
1136 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1137 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1141 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1142 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1147 * Get a hash of the ClientHello up to the start of the binders. If we are
1148 * following a HelloRetryRequest then this includes the hash of the first
1149 * ClientHello and the HelloRetryRequest itself.
1151 if (s->hello_retry_request) {
1155 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1156 if (hdatalen <= 0) {
1157 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1162 * For servers the handshake buffer data will include the second
1163 * ClientHello - which we don't want - so we need to take that bit off.
1166 if (hdatalen < s->init_num + SSL3_HM_HEADER_LENGTH) {
1167 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1170 hdatalen -= s->init_num + SSL3_HM_HEADER_LENGTH;
1173 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1174 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1179 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1180 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1181 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1185 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1186 if (mackey == NULL) {
1187 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1192 binderout = tmpbinder;
1194 bindersize = hashsize;
1195 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1196 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1197 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1198 || bindersize != hashsize) {
1199 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1206 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1207 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1211 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1212 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1213 EVP_PKEY_free(mackey);
1214 EVP_MD_CTX_free(mctx);