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
139 TLSEXT_TYPE_early_data,
140 EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
141 NULL, NULL, NULL, NULL, tls_construct_ctos_early_data, NULL
143 #ifndef OPENSSL_NO_EC
145 TLSEXT_TYPE_ec_point_formats,
146 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
147 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
148 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
152 TLSEXT_TYPE_supported_groups,
153 EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
154 NULL, tls_parse_ctos_supported_groups, NULL,
155 NULL /* TODO(TLS1.3): Need to add this */,
156 tls_construct_ctos_supported_groups, NULL
163 TLSEXT_TYPE_session_ticket,
164 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
165 init_session_ticket, tls_parse_ctos_session_ticket,
166 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
167 tls_construct_ctos_session_ticket, NULL
170 TLSEXT_TYPE_signature_algorithms,
172 init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
173 tls_construct_ctos_sig_algs, final_sig_algs
175 #ifndef OPENSSL_NO_OCSP
177 TLSEXT_TYPE_status_request,
178 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
179 | EXT_TLS1_3_CERTIFICATE,
180 init_status_request, tls_parse_ctos_status_request,
181 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
182 tls_construct_ctos_status_request, NULL
187 #ifndef OPENSSL_NO_NEXTPROTONEG
189 TLSEXT_TYPE_next_proto_neg,
190 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
191 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
192 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
199 * Must appear in this list after server_name so that finalisation
200 * happens after server_name callbacks
202 TLSEXT_TYPE_application_layer_protocol_negotiation,
203 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
204 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
205 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
206 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
208 #ifndef OPENSSL_NO_SRTP
210 TLSEXT_TYPE_use_srtp,
211 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
212 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS | EXT_DTLS_ONLY,
213 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
214 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
220 TLSEXT_TYPE_encrypt_then_mac,
221 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY | EXT_SSL3_ALLOWED,
222 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
223 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
225 #ifndef OPENSSL_NO_CT
227 TLSEXT_TYPE_signed_certificate_timestamp,
228 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
229 | EXT_TLS1_3_CERTIFICATE,
232 * No server side support for this, but can be provided by a custom
233 * extension. This is an exception to the rule that custom extensions
234 * cannot override built in ones.
236 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
242 TLSEXT_TYPE_extended_master_secret,
243 EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
244 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
245 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
248 TLSEXT_TYPE_supported_versions,
249 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
251 /* Processed inline as part of version selection */
252 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
255 TLSEXT_TYPE_psk_kex_modes,
256 EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
257 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
258 tls_construct_ctos_psk_kex_modes, NULL
260 #ifndef OPENSSL_NO_EC
263 * Must be in this list after supported_groups. We need that to have
264 * been parsed before we do this one.
266 TLSEXT_TYPE_key_share,
267 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO
268 | EXT_TLS1_3_HELLO_RETRY_REQUEST | EXT_TLS_IMPLEMENTATION_ONLY
270 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
271 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
277 * Special unsolicited ServerHello extension only used when
278 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
280 TLSEXT_TYPE_cryptopro_bug,
281 EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
282 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
285 /* Must be immediately before pre_shared_key */
286 /* TODO(TLS1.3): Fix me */
290 /* We send this, but don't read it */
291 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
294 /* Required by the TLSv1.3 spec to always be the last extension */
296 EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO | EXT_TLS_IMPLEMENTATION_ONLY
298 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
299 tls_construct_ctos_psk, NULL
304 * Verify whether we are allowed to use the extension |type| in the current
305 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
306 * indicate the extension is not allowed. If returning 1 then |*found| is set to
307 * 1 if we found a definition for the extension, and |*idx| is set to its index
309 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
310 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
311 RAW_EXTENSION **found)
314 size_t builtin_num = OSSL_NELEM(ext_defs);
315 const EXTENSION_DEFINITION *thisext;
317 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
318 if (type == thisext->type) {
319 /* Check we're allowed to use this extension in this context */
320 if ((context & thisext->context) == 0)
323 if (SSL_IS_DTLS(s)) {
324 if ((thisext->context & EXT_TLS_ONLY) != 0)
326 } else if ((thisext->context & EXT_DTLS_ONLY) != 0) {
330 *found = &rawexlist[i];
335 if ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) == 0) {
337 * Custom extensions only apply to <=TLS1.2. This extension is unknown
338 * in this context - we allow it
344 /* Check the custom extensions */
346 for (i = builtin_num; i < builtin_num + meths->meths_count; i++) {
347 if (meths->meths[i - builtin_num].ext_type == type) {
348 *found = &rawexlist[i];
354 /* Unknown extension. We allow it */
360 * Check whether the context defined for an extension |extctx| means whether
361 * the extension is relevant for the current context |thisctx| or not. Returns
362 * 1 if the extension is relevant for this context, and 0 otherwise
364 static int extension_is_relevant(SSL *s, unsigned int extctx,
365 unsigned int thisctx)
368 && (extctx & EXT_TLS_IMPLEMENTATION_ONLY) != 0)
369 || (s->version == SSL3_VERSION
370 && (extctx & EXT_SSL3_ALLOWED) == 0)
372 && (extctx & EXT_TLS1_2_AND_BELOW_ONLY) != 0)
373 || (!SSL_IS_TLS13(s) && (extctx & EXT_TLS1_3_ONLY) != 0))
380 * Gather a list of all the extensions from the data in |packet]. |context|
381 * tells us which message this extension is for. The raw extension data is
382 * stored in |*res| on success. In the event of an error the alert type to use
383 * is stored in |*al|. We don't actually process the content of the extensions
384 * yet, except to check their types. This function also runs the initialiser
385 * functions for all known extensions (whether we have collected them or not).
386 * If successful the caller is responsible for freeing the contents of |*res|.
388 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
389 * more than one extension of the same type in a ClientHello or ServerHello.
390 * This function returns 1 if all extensions are unique and we have parsed their
391 * types, and 0 if the extensions contain duplicates, could not be successfully
392 * found, or an internal error occurred. We only check duplicates for
393 * extensions that we know about. We ignore others.
395 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
396 RAW_EXTENSION **res, int *al, size_t *len)
398 PACKET extensions = *packet;
401 custom_ext_methods *exts = NULL;
402 RAW_EXTENSION *raw_extensions = NULL;
403 const EXTENSION_DEFINITION *thisexd;
408 * Initialise server side custom extensions. Client side is done during
409 * construction of extensions for the ClientHello.
411 if ((context & EXT_CLIENT_HELLO) != 0) {
412 exts = &s->cert->srv_ext;
413 custom_ext_init(&s->cert->srv_ext);
414 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
415 exts = &s->cert->cli_ext;
418 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
419 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
420 if (raw_extensions == NULL) {
421 *al = SSL_AD_INTERNAL_ERROR;
422 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
426 while (PACKET_remaining(&extensions) > 0) {
429 RAW_EXTENSION *thisex;
431 if (!PACKET_get_net_2(&extensions, &type) ||
432 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
433 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
434 *al = SSL_AD_DECODE_ERROR;
438 * Verify this extension is allowed. We only check duplicates for
439 * extensions that we recognise.
441 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
442 || (thisex != NULL && thisex->present == 1)) {
443 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
444 *al = SSL_AD_ILLEGAL_PARAMETER;
447 if (thisex != NULL) {
448 thisex->data = extension;
455 * Initialise all known extensions relevant to this context, whether we have
458 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
459 if(thisexd->init != NULL && (thisexd->context & context) != 0
460 && extension_is_relevant(s, thisexd->context, context)
461 && !thisexd->init(s, context)) {
462 *al = SSL_AD_INTERNAL_ERROR;
467 *res = raw_extensions;
473 OPENSSL_free(raw_extensions);
478 * Runs the parser for a given extension with index |idx|. |exts| contains the
479 * list of all parsed extensions previously collected by
480 * tls_collect_extensions(). The parser is only run if it is applicable for the
481 * given |context| and the parser has not already been run. If this is for a
482 * Certificate message, then we also provide the parser with the relevant
483 * Certificate |x| and its position in the |chainidx| with 0 being the first
484 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
485 * |*al| is populated with a suitable alert code. If an extension is not present
486 * this counted as success.
488 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
489 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
491 RAW_EXTENSION *currext = &exts[idx];
492 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
493 size_t chainidx, int *al) = NULL;
495 /* Skip if the extension is not present */
496 if (!currext->present)
500 s->ext.debug_cb(s, !s->server, currext->type,
501 PACKET_data(&currext->data),
502 PACKET_remaining(&currext->data),
505 /* Skip if we've already parsed this extension */
511 if (idx < OSSL_NELEM(ext_defs)) {
512 /* We are handling a built-in extension */
513 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
515 /* Check if extension is defined for our protocol. If not, skip */
516 if (!extension_is_relevant(s, extdef->context, context))
519 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
522 return parser(s, &currext->data, context, x, chainidx, al);
525 * If the parser is NULL we fall through to the custom extension
531 * This is a custom extension. We only allow this if it is a non
532 * resumed session on the server side.
534 * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
535 * We're going to need a new mechanism for TLS1.3 to specify which
536 * messages to add the custom extensions to.
538 if ((!s->hit || !s->server)
540 & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
541 && custom_ext_parse(s, s->server, currext->type,
542 PACKET_data(&currext->data),
543 PACKET_remaining(&currext->data),
551 * Parse all remaining extensions that have not yet been parsed. Also calls the
552 * finalisation for all extensions at the end, whether we collected them or not.
553 * Returns 1 for success or 0 for failure. If we are working on a Certificate
554 * message then we also pass the Certificate |x| and its position in the
555 * |chainidx|, with 0 being the first certificate. On failure, |*al| is
556 * populated with a suitable alert code.
558 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
559 size_t chainidx, int *al)
561 size_t i, numexts = OSSL_NELEM(ext_defs);
562 const EXTENSION_DEFINITION *thisexd;
564 /* Calculate the number of extensions in the extensions list */
565 if ((context & EXT_CLIENT_HELLO) != 0) {
566 numexts += s->cert->srv_ext.meths_count;
567 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
568 numexts += s->cert->cli_ext.meths_count;
571 /* Parse each extension in turn */
572 for (i = 0; i < numexts; i++) {
573 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
578 * Finalise all known extensions relevant to this context, whether we have
581 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
582 if(thisexd->final != NULL
583 && (thisexd->context & context) != 0
584 && !thisexd->final(s, context, exts[i].present, al))
592 * Construct all the extensions relevant to the current |context| and write
593 * them to |pkt|. If this is an extension for a Certificate in a Certificate
594 * message, then |x| will be set to the Certificate we are handling, and
595 * |chainidx| will indicate the position in the chainidx we are processing (with
596 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
597 * failure occurs then |al| is populated with a suitable alert code. On a
598 * failure construction stops at the first extension to fail to construct.
600 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
601 X509 *x, size_t chainidx, int *al)
604 int addcustom = 0, min_version, max_version = 0, reason, tmpal;
605 const EXTENSION_DEFINITION *thisexd;
608 * Normally if something goes wrong during construction it's an internal
609 * error. We can always override this later.
611 tmpal = SSL_AD_INTERNAL_ERROR;
613 if (!WPACKET_start_sub_packet_u16(pkt)
615 * If extensions are of zero length then we don't even add the
616 * extensions length bytes to a ClientHello/ServerHello in SSLv3
618 || ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
619 && s->version == SSL3_VERSION
620 && !WPACKET_set_flags(pkt,
621 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
622 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
626 if ((context & EXT_CLIENT_HELLO) != 0) {
627 reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
629 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
634 /* Add custom extensions first */
635 if ((context & EXT_CLIENT_HELLO) != 0) {
636 custom_ext_init(&s->cert->cli_ext);
638 } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
640 * We already initialised the custom extensions during ClientHello
643 * TODO(TLS1.3): We're going to need a new custom extension mechanism
644 * for TLS1.3, so that custom extensions can specify which of the
645 * multiple message they wish to add themselves to.
650 if (addcustom && !custom_ext_add(s, s->server, pkt, &tmpal)) {
651 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
655 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
656 int (*construct)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
657 size_t chainidx, int *al);
659 /* Skip if not relevant for our context */
660 if ((thisexd->context & context) == 0)
663 construct = s->server ? thisexd->construct_stoc
664 : thisexd->construct_ctos;
666 /* Check if this extension is defined for our protocol. If not, skip */
668 && (thisexd->context & EXT_TLS_IMPLEMENTATION_ONLY)
670 || (s->version == SSL3_VERSION
671 && (thisexd->context & EXT_SSL3_ALLOWED) == 0)
673 && (thisexd->context & EXT_TLS1_2_AND_BELOW_ONLY)
676 && (thisexd->context & EXT_TLS1_3_ONLY) != 0
677 && (context & EXT_CLIENT_HELLO) == 0)
678 || ((thisexd->context & EXT_TLS1_3_ONLY) != 0
679 && (context & EXT_CLIENT_HELLO) != 0
680 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
681 || construct == NULL)
684 if (!construct(s, pkt, context, x, chainidx, &tmpal))
688 if (!WPACKET_close(pkt)) {
689 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
701 * Built in extension finalisation and initialisation functions. All initialise
702 * or finalise the associated extension type for the given |context|. For
703 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
704 * otherwise. These functions return 1 on success or 0 on failure. In the event
705 * of a failure then |*al| is populated with a suitable error code.
708 static int final_renegotiate(SSL *s, unsigned int context, int sent,
713 * Check if we can connect to a server that doesn't support safe
716 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
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);
728 /* Need RI if renegotiating */
730 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
732 *al = SSL_AD_HANDSHAKE_FAILURE;
733 SSLerr(SSL_F_FINAL_RENEGOTIATE,
734 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
742 static int init_server_name(SSL *s, unsigned int context)
745 s->servername_done = 0;
750 static int final_server_name(SSL *s, unsigned int context, int sent,
753 int ret = SSL_TLSEXT_ERR_NOACK;
754 int altmp = SSL_AD_UNRECOGNIZED_NAME;
756 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
757 ret = s->ctx->ext.servername_cb(s, &altmp,
758 s->ctx->ext.servername_arg);
759 else if (s->session_ctx != NULL
760 && s->session_ctx->ext.servername_cb != 0)
761 ret = s->session_ctx->ext.servername_cb(s, &altmp,
762 s->session_ctx->ext.servername_arg);
765 case SSL_TLSEXT_ERR_ALERT_FATAL:
769 case SSL_TLSEXT_ERR_ALERT_WARNING:
773 case SSL_TLSEXT_ERR_NOACK:
774 s->servername_done = 0;
782 #ifndef OPENSSL_NO_EC
783 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
786 unsigned long alg_k, alg_a;
791 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
792 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
795 * If we are client and using an elliptic curve cryptography cipher
796 * suite, then if server returns an EC point formats lists extension it
797 * must contain uncompressed.
799 if (s->ext.ecpointformats != NULL
800 && s->ext.ecpointformats_len > 0
801 && s->session->ext.ecpointformats != NULL
802 && s->session->ext.ecpointformats_len > 0
803 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
804 /* we are using an ECC cipher */
806 unsigned char *list = s->session->ext.ecpointformats;
808 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
809 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
812 if (i == s->session->ext.ecpointformats_len) {
813 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
814 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
823 static int init_session_ticket(SSL *s, unsigned int context)
826 s->ext.ticket_expected = 0;
831 #ifndef OPENSSL_NO_OCSP
832 static int init_status_request(SSL *s, unsigned int context)
835 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
838 * Ensure we get sensible values passed to tlsext_status_cb in the event
839 * that we don't receive a status message
841 OPENSSL_free(s->ext.ocsp.resp);
842 s->ext.ocsp.resp = NULL;
843 s->ext.ocsp.resp_len = 0;
850 #ifndef OPENSSL_NO_NEXTPROTONEG
851 static int init_npn(SSL *s, unsigned int context)
859 static int init_alpn(SSL *s, unsigned int context)
861 OPENSSL_free(s->s3->alpn_selected);
862 s->s3->alpn_selected = NULL;
864 s->s3->alpn_selected_len = 0;
865 OPENSSL_free(s->s3->alpn_proposed);
866 s->s3->alpn_proposed = NULL;
867 s->s3->alpn_proposed_len = 0;
872 static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
874 const unsigned char *selected = NULL;
875 unsigned char selected_len = 0;
880 if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
881 int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
882 s->s3->alpn_proposed,
883 (unsigned int)s->s3->alpn_proposed_len,
884 s->ctx->ext.alpn_select_cb_arg);
886 if (r == SSL_TLSEXT_ERR_OK) {
887 OPENSSL_free(s->s3->alpn_selected);
888 s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
889 if (s->s3->alpn_selected == NULL) {
890 *al = SSL_AD_INTERNAL_ERROR;
893 s->s3->alpn_selected_len = selected_len;
894 #ifndef OPENSSL_NO_NEXTPROTONEG
895 /* ALPN takes precedence over NPN. */
899 *al = SSL_AD_NO_APPLICATION_PROTOCOL;
907 static int init_sig_algs(SSL *s, unsigned int context)
909 /* Clear any signature algorithms extension received */
910 OPENSSL_free(s->s3->tmp.peer_sigalgs);
911 s->s3->tmp.peer_sigalgs = NULL;
916 #ifndef OPENSSL_NO_SRP
917 static int init_srp(SSL *s, unsigned int context)
919 OPENSSL_free(s->srp_ctx.login);
920 s->srp_ctx.login = NULL;
926 static int init_etm(SSL *s, unsigned int context)
933 static int init_ems(SSL *s, unsigned int context)
936 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
941 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
943 if (!s->server && s->hit) {
945 * Check extended master secret extension is consistent with
948 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
949 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
950 *al = SSL_AD_HANDSHAKE_FAILURE;
951 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
959 #ifndef OPENSSL_NO_SRTP
960 static int init_srtp(SSL *s, unsigned int context)
963 s->srtp_profile = NULL;
969 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
971 if (!sent && SSL_IS_TLS13(s)) {
972 *al = TLS13_AD_MISSING_EXTENSION;
973 SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
980 #ifndef OPENSSL_NO_EC
981 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
983 if (!SSL_IS_TLS13(s))
990 * we have no key_share
992 * (we are not resuming
993 * OR the kex_mode doesn't allow non key_share resumes)
1000 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
1001 /* Nothing left we can do - just fail */
1002 *al = SSL_AD_HANDSHAKE_FAILURE;
1003 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1010 * we have no key_share
1013 * we didn't already send a HelloRetryRequest
1015 * the client sent a key_share extension
1017 * (we are not resuming
1018 * OR the kex_mode allows key_share resumes)
1020 * a shared group exists
1022 * send a HelloRetryRequest
1024 * we are not resuming
1026 * the kex_mode doesn't allow non key_share resumes
1030 if (s->server && s->s3->peer_tmp == NULL) {
1031 /* No suitable share */
1032 if (s->hello_retry_request == 0 && sent
1034 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1036 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1037 size_t num_curves, clnt_num_curves, i;
1038 unsigned int group_id = 0;
1040 /* Check if a shared group exists */
1042 /* Get the clients list of supported groups. */
1043 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1044 *al = SSL_AD_INTERNAL_ERROR;
1045 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1049 /* Get our list of available groups */
1050 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1051 *al = SSL_AD_INTERNAL_ERROR;
1052 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1056 /* Find the first group we allow that is also in client's list */
1057 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1058 i++, pcurvestmp += 2) {
1059 group_id = bytestogroup(pcurvestmp);
1061 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1065 if (i < num_curves) {
1066 /* A shared group exists so send a HelloRetryRequest */
1067 s->s3->group_id = group_id;
1068 s->hello_retry_request = 1;
1073 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1074 /* Nothing left we can do - just fail */
1075 *al = SSL_AD_HANDSHAKE_FAILURE;
1076 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1081 /* We have a key_share so don't send any more HelloRetryRequest messages */
1083 s->hello_retry_request = 0;
1086 * For a client side resumption with no key_share we need to generate
1087 * the handshake secret (otherwise this is done during key_share
1090 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1091 *al = SSL_AD_INTERNAL_ERROR;
1092 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1100 static int init_psk_kex_modes(SSL *s, unsigned int context)
1102 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1106 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1107 size_t binderoffset, const unsigned char *binderin,
1108 unsigned char *binderout,
1109 SSL_SESSION *sess, int sign)
1111 EVP_PKEY *mackey = NULL;
1112 EVP_MD_CTX *mctx = NULL;
1113 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1114 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1115 const char resumption_label[] = "resumption psk binder key";
1116 size_t bindersize, hashsize = EVP_MD_size(md);
1119 /* Generate the early_secret */
1120 if (!tls13_generate_secret(s, md, NULL, sess->master_key,
1121 sess->master_key_length,
1122 (unsigned char *)&s->early_secret)) {
1123 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1128 * Create the handshake hash for the binder key...the messages so far are
1131 mctx = EVP_MD_CTX_new();
1133 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1134 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1135 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1139 /* Generate the binder key */
1140 if (!tls13_hkdf_expand(s, md, s->early_secret,
1141 (unsigned char *)resumption_label,
1142 sizeof(resumption_label) - 1, hash, binderkey,
1144 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1148 /* Generate the finished key */
1149 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1150 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1154 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1155 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1160 * Get a hash of the ClientHello up to the start of the binders. If we are
1161 * following a HelloRetryRequest then this includes the hash of the first
1162 * ClientHello and the HelloRetryRequest itself.
1164 if (s->hello_retry_request) {
1168 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1169 if (hdatalen <= 0) {
1170 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1175 * For servers the handshake buffer data will include the second
1176 * ClientHello - which we don't want - so we need to take that bit off.
1179 if (hdatalen < s->init_num + SSL3_HM_HEADER_LENGTH) {
1180 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1183 hdatalen -= s->init_num + SSL3_HM_HEADER_LENGTH;
1186 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1187 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1192 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1193 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1194 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1198 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1199 if (mackey == NULL) {
1200 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1205 binderout = tmpbinder;
1207 bindersize = hashsize;
1208 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1209 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1210 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1211 || bindersize != hashsize) {
1212 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1219 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1220 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1224 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1225 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1226 EVP_PKEY_free(mackey);
1227 EVP_MD_CTX_free(mctx);