2 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 #include "../ssl_locl.h"
12 #include "statem_locl.h"
14 static int final_renegotiate(SSL *s, unsigned int context, int sent,
16 static int init_server_name(SSL *s, unsigned int context);
17 static int final_server_name(SSL *s, unsigned int context, int sent,
20 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
23 static int init_session_ticket(SSL *s, unsigned int context);
24 #ifndef OPENSSL_NO_OCSP
25 static int init_status_request(SSL *s, unsigned int context);
27 #ifndef OPENSSL_NO_NEXTPROTONEG
28 static int init_npn(SSL *s, unsigned int context);
30 static int init_alpn(SSL *s, unsigned int context);
31 static int final_alpn(SSL *s, unsigned int context, int sent, int *al);
32 static int init_sig_algs(SSL *s, unsigned int context);
33 static int init_certificate_authorities(SSL *s, unsigned int context);
34 static int tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
35 unsigned int context, X509 *x,
36 size_t chainidx, int *al);
37 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
38 unsigned int context, X509 *x,
39 size_t chainidx, int *al);
40 #ifndef OPENSSL_NO_SRP
41 static int init_srp(SSL *s, unsigned int context);
43 static int init_etm(SSL *s, unsigned int context);
44 static int init_ems(SSL *s, unsigned int context);
45 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
46 static int init_psk_kex_modes(SSL *s, unsigned int context);
48 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
50 #ifndef OPENSSL_NO_SRTP
51 static int init_srtp(SSL *s, unsigned int context);
53 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
54 static int final_early_data(SSL *s, unsigned int context, int sent, int *al);
56 /* Structure to define a built-in extension */
57 typedef struct extensions_definition_st {
58 /* The defined type for the extension */
61 * The context that this extension applies to, e.g. what messages and
66 * Initialise extension before parsing. Always called for relevant contexts
67 * even if extension not present
69 int (*init)(SSL *s, unsigned int context);
70 /* Parse extension sent from client to server */
71 int (*parse_ctos)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
72 size_t chainidx, int *al);
73 /* Parse extension send from server to client */
74 int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
75 size_t chainidx, int *al);
76 /* Construct extension sent from server to client */
77 int (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
78 size_t chainidx, int *al);
79 /* Construct extension sent from client to server */
80 int (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
81 size_t chainidx, int *al);
83 * Finalise extension after parsing. Always called where an extensions was
84 * initialised even if the extension was not present. |sent| is set to 1 if
85 * the extension was seen, or 0 otherwise.
87 int (*final)(SSL *s, unsigned int context, int sent, int *al);
88 } EXTENSION_DEFINITION;
91 * Definitions of all built-in extensions. NOTE: Changes in the number or order
92 * of these extensions should be mirrored with equivalent changes to the
93 * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
94 * Each extension has an initialiser, a client and
95 * server side parser and a finaliser. The initialiser is called (if the
96 * extension is relevant to the given context) even if we did not see the
97 * extension in the message that we received. The parser functions are only
98 * called if we see the extension in the message. The finalisers are always
99 * called if the initialiser was called.
100 * There are also server and client side constructor functions which are always
101 * called during message construction if the extension is relevant for the
103 * The initialisation, parsing, finalisation and construction functions are
104 * always called in the order defined in this list. Some extensions may depend
105 * on others having been processed first, so the order of this list is
107 * The extension context is defined by a series of flags which specify which
108 * messages the extension is relevant to. These flags also specify whether the
109 * extension is relevant to a particular protocol or protocol version.
111 * TODO(TLS1.3): Make sure we have a test to check the consistency of these
113 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL }
114 static const EXTENSION_DEFINITION ext_defs[] = {
116 TLSEXT_TYPE_renegotiate,
117 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
118 | SSL_EXT_SSL3_ALLOWED | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
119 NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
120 tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
124 TLSEXT_TYPE_server_name,
125 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
126 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
128 tls_parse_ctos_server_name, tls_parse_stoc_server_name,
129 tls_construct_stoc_server_name, tls_construct_ctos_server_name,
132 #ifndef OPENSSL_NO_SRP
135 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
136 init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
141 #ifndef OPENSSL_NO_EC
143 TLSEXT_TYPE_ec_point_formats,
144 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
145 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
146 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
147 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
151 TLSEXT_TYPE_supported_groups,
152 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
153 NULL, tls_parse_ctos_supported_groups, NULL,
154 NULL /* TODO(TLS1.3): Need to add this */,
155 tls_construct_ctos_supported_groups, NULL
162 TLSEXT_TYPE_session_ticket,
163 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
164 | SSL_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,
171 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST,
172 init_sig_algs, tls_parse_ctos_sig_algs,
173 tls_parse_ctos_sig_algs, tls_construct_ctos_sig_algs,
174 tls_construct_ctos_sig_algs, final_sig_algs
176 #ifndef OPENSSL_NO_OCSP
178 TLSEXT_TYPE_status_request,
179 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
180 | SSL_EXT_TLS1_3_CERTIFICATE,
181 init_status_request, tls_parse_ctos_status_request,
182 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
183 tls_construct_ctos_status_request, NULL
188 #ifndef OPENSSL_NO_NEXTPROTONEG
190 TLSEXT_TYPE_next_proto_neg,
191 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
192 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
193 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
194 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
201 * Must appear in this list after server_name so that finalisation
202 * happens after server_name callbacks
204 TLSEXT_TYPE_application_layer_protocol_negotiation,
205 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
206 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
207 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
208 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
210 #ifndef OPENSSL_NO_SRTP
212 TLSEXT_TYPE_use_srtp,
213 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
214 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS | SSL_EXT_DTLS_ONLY,
215 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
216 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
222 TLSEXT_TYPE_encrypt_then_mac,
223 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
224 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
225 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
226 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
228 #ifndef OPENSSL_NO_CT
230 TLSEXT_TYPE_signed_certificate_timestamp,
231 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
232 | SSL_EXT_TLS1_3_CERTIFICATE,
235 * No server side support for this, but can be provided by a custom
236 * extension. This is an exception to the rule that custom extensions
237 * cannot override built in ones.
239 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
245 TLSEXT_TYPE_extended_master_secret,
246 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
247 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
248 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
249 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
252 TLSEXT_TYPE_supported_versions,
253 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
254 | SSL_EXT_TLS1_3_ONLY,
256 /* Processed inline as part of version selection */
257 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
260 TLSEXT_TYPE_psk_kex_modes,
261 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
262 | SSL_EXT_TLS1_3_ONLY,
263 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
264 tls_construct_ctos_psk_kex_modes, NULL
266 #ifndef OPENSSL_NO_EC
269 * Must be in this list after supported_groups. We need that to have
270 * been parsed before we do this one.
272 TLSEXT_TYPE_key_share,
273 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
274 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY
275 | SSL_EXT_TLS1_3_ONLY,
276 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
277 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
283 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
284 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
285 NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
290 * Special unsolicited ServerHello extension only used when
291 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
293 TLSEXT_TYPE_cryptopro_bug,
294 SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
295 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
298 TLSEXT_TYPE_early_data,
299 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
300 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
301 NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data,
302 tls_construct_stoc_early_data, tls_construct_ctos_early_data,
306 TLSEXT_TYPE_certificate_authorities,
307 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
308 | SSL_EXT_TLS1_3_ONLY,
309 init_certificate_authorities,
310 tls_parse_certificate_authorities, tls_parse_certificate_authorities,
311 tls_construct_certificate_authorities,
312 tls_construct_certificate_authorities, NULL,
315 /* Must be immediately before pre_shared_key */
317 SSL_EXT_CLIENT_HELLO,
319 /* We send this, but don't read it */
320 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
323 /* Required by the TLSv1.3 spec to always be the last extension */
325 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
326 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
327 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
328 tls_construct_ctos_psk, NULL
333 * Verify whether we are allowed to use the extension |type| in the current
334 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
335 * indicate the extension is not allowed. If returning 1 then |*found| is set to
336 * the definition for the extension we found.
338 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
339 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
340 RAW_EXTENSION **found)
343 size_t builtin_num = OSSL_NELEM(ext_defs);
344 const EXTENSION_DEFINITION *thisext;
346 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
347 if (type == thisext->type) {
348 /* Check we're allowed to use this extension in this context */
349 if ((context & thisext->context) == 0)
352 if (SSL_IS_DTLS(s)) {
353 if ((thisext->context & SSL_EXT_TLS_ONLY) != 0)
355 } else if ((thisext->context & SSL_EXT_DTLS_ONLY) != 0) {
359 *found = &rawexlist[i];
364 if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) == 0) {
366 * Custom extensions only apply to <=TLS1.2. This extension is unknown
367 * in this context - we allow it
373 /* Check the custom extensions */
375 for (i = builtin_num; i < builtin_num + meths->meths_count; i++) {
376 if (meths->meths[i - builtin_num].ext_type == type) {
377 *found = &rawexlist[i];
383 /* Unknown extension. We allow it */
389 * Check whether the context defined for an extension |extctx| means whether
390 * the extension is relevant for the current context |thisctx| or not. Returns
391 * 1 if the extension is relevant for this context, and 0 otherwise
393 static int extension_is_relevant(SSL *s, unsigned int extctx,
394 unsigned int thisctx)
397 && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
398 || (s->version == SSL3_VERSION
399 && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
401 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
402 || (!SSL_IS_TLS13(s) && (extctx & SSL_EXT_TLS1_3_ONLY) != 0))
409 * Gather a list of all the extensions from the data in |packet]. |context|
410 * tells us which message this extension is for. The raw extension data is
411 * stored in |*res| on success. In the event of an error the alert type to use
412 * is stored in |*al|. We don't actually process the content of the extensions
413 * yet, except to check their types. This function also runs the initialiser
414 * functions for all known extensions (whether we have collected them or not).
415 * If successful the caller is responsible for freeing the contents of |*res|.
417 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
418 * more than one extension of the same type in a ClientHello or ServerHello.
419 * This function returns 1 if all extensions are unique and we have parsed their
420 * types, and 0 if the extensions contain duplicates, could not be successfully
421 * found, or an internal error occurred. We only check duplicates for
422 * extensions that we know about. We ignore others.
424 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
425 RAW_EXTENSION **res, int *al, size_t *len)
427 PACKET extensions = *packet;
430 custom_ext_methods *exts = NULL;
431 RAW_EXTENSION *raw_extensions = NULL;
432 const EXTENSION_DEFINITION *thisexd;
437 * Initialise server side custom extensions. Client side is done during
438 * construction of extensions for the ClientHello.
440 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
441 exts = &s->cert->srv_ext;
442 custom_ext_init(&s->cert->srv_ext);
443 } else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) {
444 exts = &s->cert->cli_ext;
447 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
448 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
449 if (raw_extensions == NULL) {
450 *al = SSL_AD_INTERNAL_ERROR;
451 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
455 while (PACKET_remaining(&extensions) > 0) {
458 RAW_EXTENSION *thisex;
460 if (!PACKET_get_net_2(&extensions, &type) ||
461 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
462 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
463 *al = SSL_AD_DECODE_ERROR;
467 * Verify this extension is allowed. We only check duplicates for
468 * extensions that we recognise. We also have a special case for the
469 * PSK extension, which must be the last one in the ClientHello.
471 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
472 || (thisex != NULL && thisex->present == 1)
473 || (type == TLSEXT_TYPE_psk
474 && (context & SSL_EXT_CLIENT_HELLO) != 0
475 && PACKET_remaining(&extensions) != 0)) {
476 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
477 *al = SSL_AD_ILLEGAL_PARAMETER;
480 if (thisex != NULL) {
481 thisex->data = extension;
488 * Initialise all known extensions relevant to this context, whether we have
491 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
492 if(thisexd->init != NULL && (thisexd->context & context) != 0
493 && extension_is_relevant(s, thisexd->context, context)
494 && !thisexd->init(s, context)) {
495 *al = SSL_AD_INTERNAL_ERROR;
500 *res = raw_extensions;
506 OPENSSL_free(raw_extensions);
511 * Runs the parser for a given extension with index |idx|. |exts| contains the
512 * list of all parsed extensions previously collected by
513 * tls_collect_extensions(). The parser is only run if it is applicable for the
514 * given |context| and the parser has not already been run. If this is for a
515 * Certificate message, then we also provide the parser with the relevant
516 * Certificate |x| and its position in the |chainidx| with 0 being the first
517 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
518 * |*al| is populated with a suitable alert code. If an extension is not present
519 * this counted as success.
521 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
522 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
524 RAW_EXTENSION *currext = &exts[idx];
525 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
526 size_t chainidx, int *al) = NULL;
528 /* Skip if the extension is not present */
529 if (!currext->present)
533 s->ext.debug_cb(s, !s->server, currext->type,
534 PACKET_data(&currext->data),
535 PACKET_remaining(&currext->data),
538 /* Skip if we've already parsed this extension */
544 if (idx < OSSL_NELEM(ext_defs)) {
545 /* We are handling a built-in extension */
546 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
548 /* Check if extension is defined for our protocol. If not, skip */
549 if (!extension_is_relevant(s, extdef->context, context))
552 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
555 return parser(s, &currext->data, context, x, chainidx, al);
558 * If the parser is NULL we fall through to the custom extension
564 * This is a custom extension. We only allow this if it is a non
565 * resumed session on the server side.
567 * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
568 * We're going to need a new mechanism for TLS1.3 to specify which
569 * messages to add the custom extensions to.
571 if ((!s->hit || !s->server)
573 & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
574 && custom_ext_parse(s, s->server, currext->type,
575 PACKET_data(&currext->data),
576 PACKET_remaining(&currext->data),
584 * Parse all remaining extensions that have not yet been parsed. Also calls the
585 * finalisation for all extensions at the end, whether we collected them or not.
586 * Returns 1 for success or 0 for failure. If we are working on a Certificate
587 * message then we also pass the Certificate |x| and its position in the
588 * |chainidx|, with 0 being the first certificate. On failure, |*al| is
589 * populated with a suitable alert code.
591 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
592 size_t chainidx, int *al)
594 size_t i, numexts = OSSL_NELEM(ext_defs);
595 const EXTENSION_DEFINITION *thisexd;
597 /* Calculate the number of extensions in the extensions list */
598 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
599 numexts += s->cert->srv_ext.meths_count;
600 } else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) {
601 numexts += s->cert->cli_ext.meths_count;
604 /* Parse each extension in turn */
605 for (i = 0; i < numexts; i++) {
606 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
611 * Finalise all known extensions relevant to this context, whether we have
614 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
615 if(thisexd->final != NULL
616 && (thisexd->context & context) != 0
617 && !thisexd->final(s, context, exts[i].present, al))
625 * Construct all the extensions relevant to the current |context| and write
626 * them to |pkt|. If this is an extension for a Certificate in a Certificate
627 * message, then |x| will be set to the Certificate we are handling, and
628 * |chainidx| will indicate the position in the chainidx we are processing (with
629 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
630 * failure occurs then |al| is populated with a suitable alert code. On a
631 * failure construction stops at the first extension to fail to construct.
633 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
634 X509 *x, size_t chainidx, int *al)
637 int addcustom = 0, min_version, max_version = 0, reason, tmpal;
638 const EXTENSION_DEFINITION *thisexd;
641 * Normally if something goes wrong during construction it's an internal
642 * error. We can always override this later.
644 tmpal = SSL_AD_INTERNAL_ERROR;
646 if (!WPACKET_start_sub_packet_u16(pkt)
648 * If extensions are of zero length then we don't even add the
649 * extensions length bytes to a ClientHello/ServerHello in SSLv3
652 (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
653 && s->version == SSL3_VERSION
654 && !WPACKET_set_flags(pkt,
655 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
656 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
660 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
661 reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
663 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
668 /* Add custom extensions first */
669 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
670 custom_ext_init(&s->cert->cli_ext);
672 } else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) {
674 * We already initialised the custom extensions during ClientHello
677 * TODO(TLS1.3): We're going to need a new custom extension mechanism
678 * for TLS1.3, so that custom extensions can specify which of the
679 * multiple message they wish to add themselves to.
684 if (addcustom && !custom_ext_add(s, s->server, pkt, &tmpal)) {
685 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
689 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
690 int (*construct)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
691 size_t chainidx, int *al);
693 /* Skip if not relevant for our context */
694 if ((thisexd->context & context) == 0)
697 construct = s->server ? thisexd->construct_stoc
698 : thisexd->construct_ctos;
700 /* Check if this extension is defined for our protocol. If not, skip */
702 && (thisexd->context & SSL_EXT_TLS_IMPLEMENTATION_ONLY)
704 || (s->version == SSL3_VERSION
705 && (thisexd->context & SSL_EXT_SSL3_ALLOWED) == 0)
707 && (thisexd->context & SSL_EXT_TLS1_2_AND_BELOW_ONLY)
710 && (thisexd->context & SSL_EXT_TLS1_3_ONLY) != 0
711 && (context & SSL_EXT_CLIENT_HELLO) == 0)
712 || ((thisexd->context & SSL_EXT_TLS1_3_ONLY) != 0
713 && (context & SSL_EXT_CLIENT_HELLO) != 0
714 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
715 || construct == NULL)
718 if (!construct(s, pkt, context, x, chainidx, &tmpal))
722 if (!WPACKET_close(pkt)) {
723 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
735 * Built in extension finalisation and initialisation functions. All initialise
736 * or finalise the associated extension type for the given |context|. For
737 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
738 * otherwise. These functions return 1 on success or 0 on failure. In the event
739 * of a failure then |*al| is populated with a suitable error code.
742 static int final_renegotiate(SSL *s, unsigned int context, int sent,
747 * Check if we can connect to a server that doesn't support safe
750 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
751 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
753 *al = SSL_AD_HANDSHAKE_FAILURE;
754 SSLerr(SSL_F_FINAL_RENEGOTIATE,
755 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
762 /* Need RI if renegotiating */
764 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
766 *al = SSL_AD_HANDSHAKE_FAILURE;
767 SSLerr(SSL_F_FINAL_RENEGOTIATE,
768 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
776 static int init_server_name(SSL *s, unsigned int context)
779 s->servername_done = 0;
784 static int final_server_name(SSL *s, unsigned int context, int sent,
787 int ret = SSL_TLSEXT_ERR_NOACK;
788 int altmp = SSL_AD_UNRECOGNIZED_NAME;
790 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
791 ret = s->ctx->ext.servername_cb(s, &altmp,
792 s->ctx->ext.servername_arg);
793 else if (s->session_ctx != NULL
794 && s->session_ctx->ext.servername_cb != 0)
795 ret = s->session_ctx->ext.servername_cb(s, &altmp,
796 s->session_ctx->ext.servername_arg);
799 case SSL_TLSEXT_ERR_ALERT_FATAL:
803 case SSL_TLSEXT_ERR_ALERT_WARNING:
807 case SSL_TLSEXT_ERR_NOACK:
808 s->servername_done = 0;
816 #ifndef OPENSSL_NO_EC
817 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
820 unsigned long alg_k, alg_a;
825 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
826 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
829 * If we are client and using an elliptic curve cryptography cipher
830 * suite, then if server returns an EC point formats lists extension it
831 * must contain uncompressed.
833 if (s->ext.ecpointformats != NULL
834 && s->ext.ecpointformats_len > 0
835 && s->session->ext.ecpointformats != NULL
836 && s->session->ext.ecpointformats_len > 0
837 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
838 /* we are using an ECC cipher */
840 unsigned char *list = s->session->ext.ecpointformats;
842 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
843 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
846 if (i == s->session->ext.ecpointformats_len) {
847 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
848 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
857 static int init_session_ticket(SSL *s, unsigned int context)
860 s->ext.ticket_expected = 0;
865 #ifndef OPENSSL_NO_OCSP
866 static int init_status_request(SSL *s, unsigned int context)
869 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
872 * Ensure we get sensible values passed to tlsext_status_cb in the event
873 * that we don't receive a status message
875 OPENSSL_free(s->ext.ocsp.resp);
876 s->ext.ocsp.resp = NULL;
877 s->ext.ocsp.resp_len = 0;
884 #ifndef OPENSSL_NO_NEXTPROTONEG
885 static int init_npn(SSL *s, unsigned int context)
893 static int init_alpn(SSL *s, unsigned int context)
895 OPENSSL_free(s->s3->alpn_selected);
896 s->s3->alpn_selected = NULL;
897 s->s3->alpn_selected_len = 0;
899 OPENSSL_free(s->s3->alpn_proposed);
900 s->s3->alpn_proposed = NULL;
901 s->s3->alpn_proposed_len = 0;
906 static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
908 const unsigned char *selected = NULL;
909 unsigned char selected_len = 0;
914 if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
915 int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
916 s->s3->alpn_proposed,
917 (unsigned int)s->s3->alpn_proposed_len,
918 s->ctx->ext.alpn_select_cb_arg);
920 if (r == SSL_TLSEXT_ERR_OK) {
921 OPENSSL_free(s->s3->alpn_selected);
922 s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
923 if (s->s3->alpn_selected == NULL) {
924 *al = SSL_AD_INTERNAL_ERROR;
927 s->s3->alpn_selected_len = selected_len;
928 #ifndef OPENSSL_NO_NEXTPROTONEG
929 /* ALPN takes precedence over NPN. */
933 *al = SSL_AD_NO_APPLICATION_PROTOCOL;
941 static int init_sig_algs(SSL *s, unsigned int context)
943 /* Clear any signature algorithms extension received */
944 OPENSSL_free(s->s3->tmp.peer_sigalgs);
945 s->s3->tmp.peer_sigalgs = NULL;
950 #ifndef OPENSSL_NO_SRP
951 static int init_srp(SSL *s, unsigned int context)
953 OPENSSL_free(s->srp_ctx.login);
954 s->srp_ctx.login = NULL;
960 static int init_etm(SSL *s, unsigned int context)
967 static int init_ems(SSL *s, unsigned int context)
970 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
975 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
977 if (!s->server && s->hit) {
979 * Check extended master secret extension is consistent with
982 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
983 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
984 *al = SSL_AD_HANDSHAKE_FAILURE;
985 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
993 static int init_certificate_authorities(SSL *s, unsigned int context)
995 sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free);
996 s->s3->tmp.peer_ca_names = NULL;
1000 static int tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
1001 unsigned int context, X509 *x,
1002 size_t chainidx, int *al)
1004 const STACK_OF(X509_NAME) *ca_sk = SSL_get0_CA_list(s);
1006 if (ca_sk == NULL || sk_X509_NAME_num(ca_sk) == 0)
1009 if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_certificate_authorities)
1010 || !WPACKET_start_sub_packet_u16(pkt)
1011 || !construct_ca_names(s, pkt)
1012 || !WPACKET_close(pkt)) {
1013 SSLerr(SSL_F_TLS_CONSTRUCT_CERTIFICATE_AUTHORITIES,
1014 ERR_R_INTERNAL_ERROR);
1021 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
1022 unsigned int context, X509 *x,
1023 size_t chainidx, int *al)
1025 if (!parse_ca_names(s, pkt, al))
1027 if (PACKET_remaining(pkt) != 0) {
1028 *al = SSL_AD_DECODE_ERROR;
1034 #ifndef OPENSSL_NO_SRTP
1035 static int init_srtp(SSL *s, unsigned int context)
1038 s->srtp_profile = NULL;
1044 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
1046 if (!sent && SSL_IS_TLS13(s)) {
1047 *al = TLS13_AD_MISSING_EXTENSION;
1048 SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
1055 #ifndef OPENSSL_NO_EC
1056 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
1058 if (!SSL_IS_TLS13(s))
1065 * we have no key_share
1067 * (we are not resuming
1068 * OR the kex_mode doesn't allow non key_share resumes)
1075 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
1076 /* Nothing left we can do - just fail */
1077 *al = SSL_AD_HANDSHAKE_FAILURE;
1078 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1085 * we have no key_share
1088 * we didn't already send a HelloRetryRequest
1090 * the client sent a key_share extension
1092 * (we are not resuming
1093 * OR the kex_mode allows key_share resumes)
1095 * a shared group exists
1097 * send a HelloRetryRequest
1099 * we are not resuming
1101 * the kex_mode doesn't allow non key_share resumes
1105 if (s->server && s->s3->peer_tmp == NULL) {
1106 /* No suitable share */
1107 if (s->hello_retry_request == 0 && sent
1109 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1111 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1112 size_t num_curves, clnt_num_curves, i;
1113 unsigned int group_id = 0;
1115 /* Check if a shared group exists */
1117 /* Get the clients list of supported groups. */
1118 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1119 *al = SSL_AD_INTERNAL_ERROR;
1120 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1124 /* Get our list of available groups */
1125 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1126 *al = SSL_AD_INTERNAL_ERROR;
1127 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1131 /* Find the first group we allow that is also in client's list */
1132 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1133 i++, pcurvestmp += 2) {
1134 group_id = bytestogroup(pcurvestmp);
1136 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1140 if (i < num_curves) {
1141 /* A shared group exists so send a HelloRetryRequest */
1142 s->s3->group_id = group_id;
1143 s->hello_retry_request = 1;
1148 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1149 /* Nothing left we can do - just fail */
1150 *al = SSL_AD_HANDSHAKE_FAILURE;
1151 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1156 /* We have a key_share so don't send any more HelloRetryRequest messages */
1158 s->hello_retry_request = 0;
1161 * For a client side resumption with no key_share we need to generate
1162 * the handshake secret (otherwise this is done during key_share
1165 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1166 *al = SSL_AD_INTERNAL_ERROR;
1167 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1175 static int init_psk_kex_modes(SSL *s, unsigned int context)
1177 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1181 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1182 size_t binderoffset, const unsigned char *binderin,
1183 unsigned char *binderout,
1184 SSL_SESSION *sess, int sign)
1186 EVP_PKEY *mackey = NULL;
1187 EVP_MD_CTX *mctx = NULL;
1188 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1189 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1190 const char resumption_label[] = "resumption psk binder key";
1191 size_t bindersize, hashsize = EVP_MD_size(md);
1194 /* Generate the early_secret */
1195 if (!tls13_generate_secret(s, md, NULL, sess->master_key,
1196 sess->master_key_length,
1197 (unsigned char *)&s->early_secret)) {
1198 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1203 * Create the handshake hash for the binder key...the messages so far are
1206 mctx = EVP_MD_CTX_new();
1208 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1209 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1210 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1214 /* Generate the binder key */
1215 if (!tls13_hkdf_expand(s, md, s->early_secret,
1216 (unsigned char *)resumption_label,
1217 sizeof(resumption_label) - 1, hash, binderkey,
1219 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1223 /* Generate the finished key */
1224 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1225 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1229 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1230 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1235 * Get a hash of the ClientHello up to the start of the binders. If we are
1236 * following a HelloRetryRequest then this includes the hash of the first
1237 * ClientHello and the HelloRetryRequest itself.
1239 if (s->hello_retry_request) {
1243 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1244 if (hdatalen <= 0) {
1245 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1250 * For servers the handshake buffer data will include the second
1251 * ClientHello - which we don't want - so we need to take that bit off.
1254 PACKET hashprefix, msg;
1256 /* Find how many bytes are left after the first two messages */
1257 if (!PACKET_buf_init(&hashprefix, hdata, hdatalen)
1258 || !PACKET_forward(&hashprefix, 1)
1259 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)
1260 || !PACKET_forward(&hashprefix, 1)
1261 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) {
1262 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1265 hdatalen -= PACKET_remaining(&hashprefix);
1268 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1269 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1274 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1275 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1276 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1280 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1281 if (mackey == NULL) {
1282 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1287 binderout = tmpbinder;
1289 bindersize = hashsize;
1290 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1291 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1292 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1293 || bindersize != hashsize) {
1294 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1301 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1302 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1306 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1307 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1308 EVP_PKEY_free(mackey);
1309 EVP_MD_CTX_free(mctx);
1314 static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
1316 if (!s->server || !sent)
1319 if (s->max_early_data == 0
1321 || s->session->ext.tick_identity != 0
1322 || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
1323 || !s->ext.early_data_ok
1324 || s->hello_retry_request
1325 || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
1326 || (s->s3->alpn_selected_len > 0
1327 && memcmp(s->s3->alpn_selected, s->session->ext.alpn_selected,
1328 s->s3->alpn_selected_len) != 0)) {
1329 s->ext.early_data = SSL_EARLY_DATA_REJECTED;
1331 s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1333 if (!tls13_change_cipher_state(s,
1334 SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
1335 *al = SSL_AD_INTERNAL_ERROR;