2 * Copyright 2016-2017 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 init_sig_algs(SSL *s, unsigned int context);
32 static int init_certificate_authorities(SSL *s, unsigned int context);
33 static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
38 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
39 unsigned int context, X509 *x,
40 size_t chainidx, int *al);
41 #ifndef OPENSSL_NO_SRP
42 static int init_srp(SSL *s, unsigned int context);
44 static int init_etm(SSL *s, unsigned int context);
45 static int init_ems(SSL *s, unsigned int context);
46 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
47 static int init_psk_kex_modes(SSL *s, unsigned int context);
49 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
51 #ifndef OPENSSL_NO_SRTP
52 static int init_srtp(SSL *s, unsigned int context);
54 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
55 static int final_early_data(SSL *s, unsigned int context, int sent, int *al);
57 /* Structure to define a built-in extension */
58 typedef struct extensions_definition_st {
59 /* The defined type for the extension */
62 * The context that this extension applies to, e.g. what messages and
67 * Initialise extension before parsing. Always called for relevant contexts
68 * even if extension not present
70 int (*init)(SSL *s, unsigned int context);
71 /* Parse extension sent from client to server */
72 int (*parse_ctos)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
73 size_t chainidx, int *al);
74 /* Parse extension send from server to client */
75 int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
76 size_t chainidx, int *al);
77 /* Construct extension sent from server to client */
78 EXT_RETURN (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context,
79 X509 *x, size_t chainidx, int *al);
80 /* Construct extension sent from client to server */
81 EXT_RETURN (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context,
82 X509 *x, size_t chainidx, int *al);
84 * Finalise extension after parsing. Always called where an extensions was
85 * initialised even if the extension was not present. |sent| is set to 1 if
86 * the extension was seen, or 0 otherwise.
88 int (*final)(SSL *s, unsigned int context, int sent, int *al);
89 } EXTENSION_DEFINITION;
92 * Definitions of all built-in extensions. NOTE: Changes in the number or order
93 * of these extensions should be mirrored with equivalent changes to the
94 * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
95 * Each extension has an initialiser, a client and
96 * server side parser and a finaliser. The initialiser is called (if the
97 * extension is relevant to the given context) even if we did not see the
98 * extension in the message that we received. The parser functions are only
99 * called if we see the extension in the message. The finalisers are always
100 * called if the initialiser was called.
101 * There are also server and client side constructor functions which are always
102 * called during message construction if the extension is relevant for the
104 * The initialisation, parsing, finalisation and construction functions are
105 * always called in the order defined in this list. Some extensions may depend
106 * on others having been processed first, so the order of this list is
108 * The extension context is defined by a series of flags which specify which
109 * messages the extension is relevant to. These flags also specify whether the
110 * extension is relevant to a particular protocol or protocol version.
112 * TODO(TLS1.3): Make sure we have a test to check the consistency of these
114 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL }
115 static const EXTENSION_DEFINITION ext_defs[] = {
117 TLSEXT_TYPE_renegotiate,
118 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
119 | SSL_EXT_SSL3_ALLOWED | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
120 NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
121 tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
125 TLSEXT_TYPE_server_name,
126 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
127 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
129 tls_parse_ctos_server_name, tls_parse_stoc_server_name,
130 tls_construct_stoc_server_name, tls_construct_ctos_server_name,
133 #ifndef OPENSSL_NO_SRP
136 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
137 init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
142 #ifndef OPENSSL_NO_EC
144 TLSEXT_TYPE_ec_point_formats,
145 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
146 | SSL_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 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
154 NULL, tls_parse_ctos_supported_groups, NULL,
155 tls_construct_stoc_supported_groups,
156 tls_construct_ctos_supported_groups, NULL
163 TLSEXT_TYPE_session_ticket,
164 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
165 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
166 init_session_ticket, tls_parse_ctos_session_ticket,
167 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
168 tls_construct_ctos_session_ticket, NULL
171 TLSEXT_TYPE_signature_algorithms,
172 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST,
173 init_sig_algs, tls_parse_ctos_sig_algs,
174 tls_parse_ctos_sig_algs, tls_construct_ctos_sig_algs,
175 tls_construct_ctos_sig_algs, final_sig_algs
177 #ifndef OPENSSL_NO_OCSP
179 TLSEXT_TYPE_status_request,
180 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
181 | SSL_EXT_TLS1_3_CERTIFICATE,
182 init_status_request, tls_parse_ctos_status_request,
183 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
184 tls_construct_ctos_status_request, NULL
189 #ifndef OPENSSL_NO_NEXTPROTONEG
191 TLSEXT_TYPE_next_proto_neg,
192 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
193 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
194 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
195 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
202 * Must appear in this list after server_name so that finalisation
203 * happens after server_name callbacks
205 TLSEXT_TYPE_application_layer_protocol_negotiation,
206 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
207 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
208 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
209 tls_construct_stoc_alpn, tls_construct_ctos_alpn, NULL
211 #ifndef OPENSSL_NO_SRTP
213 TLSEXT_TYPE_use_srtp,
214 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
215 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS | SSL_EXT_DTLS_ONLY,
216 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
217 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
223 TLSEXT_TYPE_encrypt_then_mac,
224 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
225 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
226 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
227 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
229 #ifndef OPENSSL_NO_CT
231 TLSEXT_TYPE_signed_certificate_timestamp,
232 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
233 | SSL_EXT_TLS1_3_CERTIFICATE,
236 * No server side support for this, but can be provided by a custom
237 * extension. This is an exception to the rule that custom extensions
238 * cannot override built in ones.
240 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
246 TLSEXT_TYPE_extended_master_secret,
247 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
248 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
249 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
250 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
253 TLSEXT_TYPE_supported_versions,
254 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
255 | SSL_EXT_TLS1_3_ONLY,
257 /* Processed inline as part of version selection */
258 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
261 TLSEXT_TYPE_psk_kex_modes,
262 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
263 | SSL_EXT_TLS1_3_ONLY,
264 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
265 tls_construct_ctos_psk_kex_modes, NULL
267 #ifndef OPENSSL_NO_EC
270 * Must be in this list after supported_groups. We need that to have
271 * been parsed before we do this one.
273 TLSEXT_TYPE_key_share,
274 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
275 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY
276 | SSL_EXT_TLS1_3_ONLY,
277 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
278 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
284 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
285 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
286 NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
291 * Special unsolicited ServerHello extension only used when
292 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
294 TLSEXT_TYPE_cryptopro_bug,
295 SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
296 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
299 TLSEXT_TYPE_early_data,
300 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
301 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
302 NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data,
303 tls_construct_stoc_early_data, tls_construct_ctos_early_data,
307 TLSEXT_TYPE_certificate_authorities,
308 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
309 | SSL_EXT_TLS1_3_ONLY,
310 init_certificate_authorities,
311 tls_parse_certificate_authorities, tls_parse_certificate_authorities,
312 tls_construct_certificate_authorities,
313 tls_construct_certificate_authorities, NULL,
316 /* Must be immediately before pre_shared_key */
318 SSL_EXT_CLIENT_HELLO,
320 /* We send this, but don't read it */
321 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
324 /* Required by the TLSv1.3 spec to always be the last extension */
326 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
327 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
328 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
329 tls_construct_ctos_psk, NULL
333 /* Check whether an extension's context matches the current context */
334 static int validate_context(SSL *s, unsigned int extctx, unsigned int thisctx)
336 /* Check we're allowed to use this extension in this context */
337 if ((thisctx & extctx) == 0)
340 if (SSL_IS_DTLS(s)) {
341 if ((extctx & SSL_EXT_TLS_ONLY) != 0)
343 } else if ((extctx & SSL_EXT_DTLS_ONLY) != 0) {
351 * Verify whether we are allowed to use the extension |type| in the current
352 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
353 * indicate the extension is not allowed. If returning 1 then |*found| is set to
354 * the definition for the extension we found.
356 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
357 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
358 RAW_EXTENSION **found)
361 size_t builtin_num = OSSL_NELEM(ext_defs);
362 const EXTENSION_DEFINITION *thisext;
364 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
365 if (type == thisext->type) {
366 if (!validate_context(s, thisext->context, context))
369 *found = &rawexlist[i];
374 /* Check the custom extensions */
377 ENDPOINT role = ENDPOINT_BOTH;
378 custom_ext_method *meth = NULL;
380 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
381 role = ENDPOINT_SERVER;
382 else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0)
383 role = ENDPOINT_CLIENT;
385 meth = custom_ext_find(meths, role, type, &offset);
387 if (!validate_context(s, meth->context, context))
389 *found = &rawexlist[offset + builtin_num];
394 /* Unknown extension. We allow it */
400 * Check whether the context defined for an extension |extctx| means whether
401 * the extension is relevant for the current context |thisctx| or not. Returns
402 * 1 if the extension is relevant for this context, and 0 otherwise
404 int extension_is_relevant(SSL *s, unsigned int extctx, unsigned int thisctx)
407 && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
408 || (s->version == SSL3_VERSION
409 && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
411 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
412 || (!SSL_IS_TLS13(s) && (extctx & SSL_EXT_TLS1_3_ONLY) != 0)
413 || (s->hit && (extctx & SSL_EXT_IGNORE_ON_RESUMPTION) != 0))
420 * Gather a list of all the extensions from the data in |packet]. |context|
421 * tells us which message this extension is for. The raw extension data is
422 * stored in |*res| on success. In the event of an error the alert type to use
423 * is stored in |*al|. We don't actually process the content of the extensions
424 * yet, except to check their types. This function also runs the initialiser
425 * functions for all known extensions if |init| is nonzero (whether we have
426 * collected them or not). If successful the caller is responsible for freeing
427 * the contents of |*res|.
429 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
430 * more than one extension of the same type in a ClientHello or ServerHello.
431 * This function returns 1 if all extensions are unique and we have parsed their
432 * types, and 0 if the extensions contain duplicates, could not be successfully
433 * found, or an internal error occurred. We only check duplicates for
434 * extensions that we know about. We ignore others.
436 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
437 RAW_EXTENSION **res, int *al, size_t *len,
440 PACKET extensions = *packet;
443 custom_ext_methods *exts = &s->cert->custext;
444 RAW_EXTENSION *raw_extensions = NULL;
445 const EXTENSION_DEFINITION *thisexd;
450 * Initialise server side custom extensions. Client side is done during
451 * construction of extensions for the ClientHello.
453 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
454 custom_ext_init(&s->cert->custext);
456 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
457 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
458 if (raw_extensions == NULL) {
459 *al = SSL_AD_INTERNAL_ERROR;
460 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
465 while (PACKET_remaining(&extensions) > 0) {
466 unsigned int type, idx;
468 RAW_EXTENSION *thisex;
470 if (!PACKET_get_net_2(&extensions, &type) ||
471 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
472 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
473 *al = SSL_AD_DECODE_ERROR;
477 * Verify this extension is allowed. We only check duplicates for
478 * extensions that we recognise. We also have a special case for the
479 * PSK extension, which must be the last one in the ClientHello.
481 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
482 || (thisex != NULL && thisex->present == 1)
483 || (type == TLSEXT_TYPE_psk
484 && (context & SSL_EXT_CLIENT_HELLO) != 0
485 && PACKET_remaining(&extensions) != 0)) {
486 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
487 *al = SSL_AD_ILLEGAL_PARAMETER;
490 idx = thisex - raw_extensions;
492 * Check that we requested this extension (if appropriate). Requests can
493 * be sent in the ClientHello and CertificateRequest. Unsolicited
494 * extensions can be sent in the NewSessionTicket. We only do this for
495 * the built-in extensions. Custom extensions have a different but
496 * similar check elsewhere.
498 * - The HRR cookie extension is unsolicited
499 * - The renegotiate extension is unsolicited (the client signals
500 * support via an SCSV)
501 * - The signed_certificate_timestamp extension can be provided by a
502 * custom extension or by the built-in version. We let the extension
503 * itself handle unsolicited response checks.
505 if (idx < OSSL_NELEM(ext_defs)
506 && (context & (SSL_EXT_CLIENT_HELLO
507 | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
508 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) == 0
509 && type != TLSEXT_TYPE_cookie
510 && type != TLSEXT_TYPE_renegotiate
511 && type != TLSEXT_TYPE_signed_certificate_timestamp
512 && (s->ext.extflags[idx] & SSL_EXT_FLAG_SENT) == 0) {
513 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_UNSOLICITED_EXTENSION);
514 *al = SSL_AD_UNSUPPORTED_EXTENSION;
517 if (thisex != NULL) {
518 thisex->data = extension;
521 thisex->received_order = i++;
523 s->ext.debug_cb(s, !s->server, thisex->type,
524 PACKET_data(&thisex->data),
525 PACKET_remaining(&thisex->data),
532 * Initialise all known extensions relevant to this context,
533 * whether we have found them or not
535 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs);
537 if (thisexd->init != NULL && (thisexd->context & context) != 0
538 && extension_is_relevant(s, thisexd->context, context)
539 && !thisexd->init(s, context)) {
540 *al = SSL_AD_INTERNAL_ERROR;
546 *res = raw_extensions;
552 OPENSSL_free(raw_extensions);
557 * Runs the parser for a given extension with index |idx|. |exts| contains the
558 * list of all parsed extensions previously collected by
559 * tls_collect_extensions(). The parser is only run if it is applicable for the
560 * given |context| and the parser has not already been run. If this is for a
561 * Certificate message, then we also provide the parser with the relevant
562 * Certificate |x| and its position in the |chainidx| with 0 being the first
563 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
564 * |*al| is populated with a suitable alert code. If an extension is not present
565 * this counted as success.
567 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
568 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
570 RAW_EXTENSION *currext = &exts[idx];
571 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
572 size_t chainidx, int *al) = NULL;
574 /* Skip if the extension is not present */
575 if (!currext->present)
578 /* Skip if we've already parsed this extension */
584 if (idx < OSSL_NELEM(ext_defs)) {
585 /* We are handling a built-in extension */
586 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
588 /* Check if extension is defined for our protocol. If not, skip */
589 if (!extension_is_relevant(s, extdef->context, context))
592 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
595 return parser(s, &currext->data, context, x, chainidx, al);
598 * If the parser is NULL we fall through to the custom extension
603 /* Parse custom extensions */
604 if (custom_ext_parse(s, context, currext->type,
605 PACKET_data(&currext->data),
606 PACKET_remaining(&currext->data),
607 x, chainidx, al) <= 0)
614 * Parse all remaining extensions that have not yet been parsed. Also calls the
615 * finalisation for all extensions at the end if |fin| is nonzero, whether we
616 * collected them or not. Returns 1 for success or 0 for failure. If we are
617 * working on a Certificate message then we also pass the Certificate |x| and
618 * its position in the |chainidx|, with 0 being the first certificate. On
619 * failure, |*al| is populated with a suitable alert code.
621 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
622 size_t chainidx, int *al, int fin)
624 size_t i, numexts = OSSL_NELEM(ext_defs);
625 const EXTENSION_DEFINITION *thisexd;
627 /* Calculate the number of extensions in the extensions list */
628 numexts += s->cert->custext.meths_count;
630 /* Parse each extension in turn */
631 for (i = 0; i < numexts; i++) {
632 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
638 * Finalise all known extensions relevant to this context,
639 * whether we have found them or not
641 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs);
643 if (thisexd->final != NULL && (thisexd->context & context) != 0
644 && !thisexd->final(s, context, exts[i].present, al))
652 int should_add_extension(SSL *s, unsigned int extctx, unsigned int thisctx,
655 /* Skip if not relevant for our context */
656 if ((extctx & thisctx) == 0)
659 /* Check if this extension is defined for our protocol. If not, skip */
660 if ((SSL_IS_DTLS(s) && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
661 || (s->version == SSL3_VERSION
662 && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
664 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
666 && (extctx & SSL_EXT_TLS1_3_ONLY) != 0
667 && (thisctx & SSL_EXT_CLIENT_HELLO) == 0)
668 || ((extctx & SSL_EXT_TLS1_3_ONLY) != 0
669 && (thisctx & SSL_EXT_CLIENT_HELLO) != 0
670 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION)))
677 * Construct all the extensions relevant to the current |context| and write
678 * them to |pkt|. If this is an extension for a Certificate in a Certificate
679 * message, then |x| will be set to the Certificate we are handling, and
680 * |chainidx| will indicate the position in the chainidx we are processing (with
681 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
682 * failure occurs then |al| is populated with a suitable alert code. On a
683 * failure construction stops at the first extension to fail to construct.
685 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
686 X509 *x, size_t chainidx, int *al)
689 int min_version, max_version = 0, reason, tmpal;
690 const EXTENSION_DEFINITION *thisexd;
693 * Normally if something goes wrong during construction it's an internal
694 * error. We can always override this later.
696 tmpal = SSL_AD_INTERNAL_ERROR;
698 if (!WPACKET_start_sub_packet_u16(pkt)
700 * If extensions are of zero length then we don't even add the
701 * extensions length bytes to a ClientHello/ServerHello in SSLv3
704 (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
705 && s->version == SSL3_VERSION
706 && !WPACKET_set_flags(pkt,
707 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
708 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
712 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
713 reason = ssl_get_min_max_version(s, &min_version, &max_version);
715 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
720 /* Add custom extensions first */
721 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
722 /* On the server side with initialise during ClientHello parsing */
723 custom_ext_init(&s->cert->custext);
725 if (!custom_ext_add(s, context, pkt, x, chainidx, max_version, &tmpal)) {
726 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
730 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
731 EXT_RETURN (*construct)(SSL *s, WPACKET *pkt, unsigned int context,
732 X509 *x, size_t chainidx, int *al);
735 /* Skip if not relevant for our context */
736 if (!should_add_extension(s, thisexd->context, context, max_version))
739 construct = s->server ? thisexd->construct_stoc
740 : thisexd->construct_ctos;
742 if (construct == NULL)
745 ret = construct(s, pkt, context, x, chainidx, &tmpal);
746 if (ret == EXT_RETURN_FAIL)
748 if (ret == EXT_RETURN_SENT
749 && (context & (SSL_EXT_CLIENT_HELLO
750 | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
751 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) != 0)
752 s->ext.extflags[i] |= SSL_EXT_FLAG_SENT;
755 if (!WPACKET_close(pkt)) {
756 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
768 * Built in extension finalisation and initialisation functions. All initialise
769 * or finalise the associated extension type for the given |context|. For
770 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
771 * otherwise. These functions return 1 on success or 0 on failure. In the event
772 * of a failure then |*al| is populated with a suitable error code.
775 static int final_renegotiate(SSL *s, unsigned int context, int sent,
780 * Check if we can connect to a server that doesn't support safe
783 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
784 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
786 *al = SSL_AD_HANDSHAKE_FAILURE;
787 SSLerr(SSL_F_FINAL_RENEGOTIATE,
788 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
795 /* Need RI if renegotiating */
797 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
799 *al = SSL_AD_HANDSHAKE_FAILURE;
800 SSLerr(SSL_F_FINAL_RENEGOTIATE,
801 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
809 static int init_server_name(SSL *s, unsigned int context)
812 s->servername_done = 0;
817 static int final_server_name(SSL *s, unsigned int context, int sent,
820 int ret = SSL_TLSEXT_ERR_NOACK;
821 int altmp = SSL_AD_UNRECOGNIZED_NAME;
823 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
824 ret = s->ctx->ext.servername_cb(s, &altmp,
825 s->ctx->ext.servername_arg);
826 else if (s->session_ctx != NULL
827 && s->session_ctx->ext.servername_cb != 0)
828 ret = s->session_ctx->ext.servername_cb(s, &altmp,
829 s->session_ctx->ext.servername_arg);
832 case SSL_TLSEXT_ERR_ALERT_FATAL:
836 case SSL_TLSEXT_ERR_ALERT_WARNING:
840 case SSL_TLSEXT_ERR_NOACK:
841 s->servername_done = 0;
849 #ifndef OPENSSL_NO_EC
850 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
853 unsigned long alg_k, alg_a;
858 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
859 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
862 * If we are client and using an elliptic curve cryptography cipher
863 * suite, then if server returns an EC point formats lists extension it
864 * must contain uncompressed.
866 if (s->ext.ecpointformats != NULL
867 && s->ext.ecpointformats_len > 0
868 && s->session->ext.ecpointformats != NULL
869 && s->session->ext.ecpointformats_len > 0
870 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
871 /* we are using an ECC cipher */
873 unsigned char *list = s->session->ext.ecpointformats;
875 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
876 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
879 if (i == s->session->ext.ecpointformats_len) {
880 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
881 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
890 static int init_session_ticket(SSL *s, unsigned int context)
893 s->ext.ticket_expected = 0;
898 #ifndef OPENSSL_NO_OCSP
899 static int init_status_request(SSL *s, unsigned int context)
902 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
905 * Ensure we get sensible values passed to tlsext_status_cb in the event
906 * that we don't receive a status message
908 OPENSSL_free(s->ext.ocsp.resp);
909 s->ext.ocsp.resp = NULL;
910 s->ext.ocsp.resp_len = 0;
917 #ifndef OPENSSL_NO_NEXTPROTONEG
918 static int init_npn(SSL *s, unsigned int context)
926 static int init_alpn(SSL *s, unsigned int context)
928 OPENSSL_free(s->s3->alpn_selected);
929 s->s3->alpn_selected = NULL;
930 s->s3->alpn_selected_len = 0;
932 OPENSSL_free(s->s3->alpn_proposed);
933 s->s3->alpn_proposed = NULL;
934 s->s3->alpn_proposed_len = 0;
939 static int init_sig_algs(SSL *s, unsigned int context)
941 /* Clear any signature algorithms extension received */
942 OPENSSL_free(s->s3->tmp.peer_sigalgs);
943 s->s3->tmp.peer_sigalgs = NULL;
948 #ifndef OPENSSL_NO_SRP
949 static int init_srp(SSL *s, unsigned int context)
951 OPENSSL_free(s->srp_ctx.login);
952 s->srp_ctx.login = NULL;
958 static int init_etm(SSL *s, unsigned int context)
965 static int init_ems(SSL *s, unsigned int context)
968 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
973 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
975 if (!s->server && s->hit) {
977 * Check extended master secret extension is consistent with
980 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
981 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
982 *al = SSL_AD_HANDSHAKE_FAILURE;
983 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
991 static int init_certificate_authorities(SSL *s, unsigned int context)
993 sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free);
994 s->s3->tmp.peer_ca_names = NULL;
998 static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
999 unsigned int context,
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)
1007 return EXT_RETURN_NOT_SENT;
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);
1015 return EXT_RETURN_FAIL;
1018 return EXT_RETURN_SENT;
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) && !s->hit) {
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))
1061 /* Nothing to do for key_share in an HRR */
1062 if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0)
1069 * we have no key_share
1071 * (we are not resuming
1072 * OR the kex_mode doesn't allow non key_share resumes)
1079 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
1080 /* Nothing left we can do - just fail */
1081 *al = SSL_AD_MISSING_EXTENSION;
1082 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1089 * we have no key_share
1092 * we didn't already send a HelloRetryRequest
1094 * the client sent a key_share extension
1096 * (we are not resuming
1097 * OR the kex_mode allows key_share resumes)
1099 * a shared group exists
1101 * send a HelloRetryRequest
1103 * we are not resuming
1105 * the kex_mode doesn't allow non key_share resumes
1109 if (s->server && s->s3->peer_tmp == NULL) {
1110 /* No suitable share */
1111 if (s->hello_retry_request == 0 && sent
1113 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1115 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1116 size_t num_curves, clnt_num_curves, i;
1117 unsigned int group_id = 0;
1119 /* Check if a shared group exists */
1121 /* Get the clients list of supported groups. */
1122 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1123 *al = SSL_AD_INTERNAL_ERROR;
1124 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1128 /* Get our list of available groups */
1129 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1130 *al = SSL_AD_INTERNAL_ERROR;
1131 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1135 /* Find the first group we allow that is also in client's list */
1136 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1137 i++, pcurvestmp += 2) {
1138 group_id = bytestogroup(pcurvestmp);
1140 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1144 if (i < num_curves) {
1145 /* A shared group exists so send a HelloRetryRequest */
1146 s->s3->group_id = group_id;
1147 s->hello_retry_request = 1;
1152 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1153 /* Nothing left we can do - just fail */
1155 *al = SSL_AD_MISSING_EXTENSION;
1157 *al = SSL_AD_HANDSHAKE_FAILURE;
1158 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1163 /* We have a key_share so don't send any more HelloRetryRequest messages */
1165 s->hello_retry_request = 0;
1168 * For a client side resumption with no key_share we need to generate
1169 * the handshake secret (otherwise this is done during key_share
1172 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1173 *al = SSL_AD_INTERNAL_ERROR;
1174 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1182 static int init_psk_kex_modes(SSL *s, unsigned int context)
1184 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1188 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1189 size_t binderoffset, const unsigned char *binderin,
1190 unsigned char *binderout, SSL_SESSION *sess, int sign,
1193 EVP_PKEY *mackey = NULL;
1194 EVP_MD_CTX *mctx = NULL;
1195 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1196 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1197 unsigned char tmppsk[EVP_MAX_MD_SIZE];
1198 unsigned char *early_secret, *psk;
1199 const char resumption_label[] = "res binder";
1200 const char external_label[] = "ext binder";
1201 const char nonce_label[] = "resumption";
1203 size_t bindersize, labelsize, hashsize = EVP_MD_size(md);
1207 label = external_label;
1208 labelsize = sizeof(external_label) - 1;
1210 label = resumption_label;
1211 labelsize = sizeof(resumption_label) - 1;
1214 if (sess->master_key_length != hashsize) {
1215 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_PSK);
1220 psk = sess->master_key;
1223 if (!tls13_hkdf_expand(s, md, sess->master_key,
1224 (const unsigned char *)nonce_label,
1225 sizeof(nonce_label) - 1, sess->ext.tick_nonce,
1226 sess->ext.tick_nonce_len, psk, hashsize)) {
1227 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1233 * Generate the early_secret. On the server side we've selected a PSK to
1234 * resume with (internal or external) so we always do this. On the client
1235 * side we do this for a non-external (i.e. resumption) PSK so that it
1236 * is in place for sending early data. For client side external PSK we
1237 * generate it but store it away for later use.
1239 if (s->server || !external)
1240 early_secret = (unsigned char *)s->early_secret;
1242 early_secret = (unsigned char *)sess->early_secret;
1243 if (!tls13_generate_secret(s, md, NULL, psk, hashsize, early_secret)) {
1244 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1249 * Create the handshake hash for the binder key...the messages so far are
1252 mctx = EVP_MD_CTX_new();
1254 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1255 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1256 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1260 /* Generate the binder key */
1261 if (!tls13_hkdf_expand(s, md, early_secret, (unsigned char *)label,
1262 labelsize, hash, hashsize, binderkey, hashsize)) {
1263 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1267 /* Generate the finished key */
1268 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1269 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1273 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1274 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1279 * Get a hash of the ClientHello up to the start of the binders. If we are
1280 * following a HelloRetryRequest then this includes the hash of the first
1281 * ClientHello and the HelloRetryRequest itself.
1283 if (s->hello_retry_request) {
1287 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1288 if (hdatalen <= 0) {
1289 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1294 * For servers the handshake buffer data will include the second
1295 * ClientHello - which we don't want - so we need to take that bit off.
1298 PACKET hashprefix, msg;
1300 /* Find how many bytes are left after the first two messages */
1301 if (!PACKET_buf_init(&hashprefix, hdata, hdatalen)
1302 || !PACKET_forward(&hashprefix, 1)
1303 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)
1304 || !PACKET_forward(&hashprefix, 1)
1305 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) {
1306 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1309 hdatalen -= PACKET_remaining(&hashprefix);
1312 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1313 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1318 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1319 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1320 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1324 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1325 if (mackey == NULL) {
1326 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1331 binderout = tmpbinder;
1333 bindersize = hashsize;
1334 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1335 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1336 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1337 || bindersize != hashsize) {
1338 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1345 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1346 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1350 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1351 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1352 EVP_PKEY_free(mackey);
1353 EVP_MD_CTX_free(mctx);
1358 static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
1360 if (!s->server || !sent)
1363 if (s->max_early_data == 0
1365 || s->session->ext.tick_identity != 0
1366 || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
1367 || !s->ext.early_data_ok
1368 || s->hello_retry_request
1369 || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
1370 || (s->s3->alpn_selected_len > 0
1371 && memcmp(s->s3->alpn_selected, s->session->ext.alpn_selected,
1372 s->s3->alpn_selected_len) != 0)) {
1373 s->ext.early_data = SSL_EARLY_DATA_REJECTED;
1375 s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1377 if (!tls13_change_cipher_state(s,
1378 SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
1379 *al = SSL_AD_INTERNAL_ERROR;