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 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 EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
39 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
40 unsigned int context, X509 *x,
41 size_t chainidx, int *al);
42 #ifndef OPENSSL_NO_SRP
43 static int init_srp(SSL *s, unsigned int context);
45 static int init_etm(SSL *s, unsigned int context);
46 static int init_ems(SSL *s, unsigned int context);
47 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
48 static int init_psk_kex_modes(SSL *s, unsigned int context);
50 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
52 #ifndef OPENSSL_NO_SRTP
53 static int init_srtp(SSL *s, unsigned int context);
55 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
56 static int final_early_data(SSL *s, unsigned int context, int sent, int *al);
58 /* Structure to define a built-in extension */
59 typedef struct extensions_definition_st {
60 /* The defined type for the extension */
63 * The context that this extension applies to, e.g. what messages and
68 * Initialise extension before parsing. Always called for relevant contexts
69 * even if extension not present
71 int (*init)(SSL *s, unsigned int context);
72 /* Parse extension sent from client to server */
73 int (*parse_ctos)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
74 size_t chainidx, int *al);
75 /* Parse extension send from server to client */
76 int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
77 size_t chainidx, int *al);
78 /* Construct extension sent from server to client */
79 EXT_RETURN (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context,
80 X509 *x, size_t chainidx, int *al);
81 /* Construct extension sent from client to server */
82 EXT_RETURN (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context,
83 X509 *x, size_t chainidx, int *al);
85 * Finalise extension after parsing. Always called where an extensions was
86 * initialised even if the extension was not present. |sent| is set to 1 if
87 * the extension was seen, or 0 otherwise.
89 int (*final)(SSL *s, unsigned int context, int sent, int *al);
90 } EXTENSION_DEFINITION;
93 * Definitions of all built-in extensions. NOTE: Changes in the number or order
94 * of these extensions should be mirrored with equivalent changes to the
95 * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
96 * Each extension has an initialiser, a client and
97 * server side parser and a finaliser. The initialiser is called (if the
98 * extension is relevant to the given context) even if we did not see the
99 * extension in the message that we received. The parser functions are only
100 * called if we see the extension in the message. The finalisers are always
101 * called if the initialiser was called.
102 * There are also server and client side constructor functions which are always
103 * called during message construction if the extension is relevant for the
105 * The initialisation, parsing, finalisation and construction functions are
106 * always called in the order defined in this list. Some extensions may depend
107 * on others having been processed first, so the order of this list is
109 * The extension context is defined by a series of flags which specify which
110 * messages the extension is relevant to. These flags also specify whether the
111 * extension is relevant to a particular protocol or protocol version.
113 * TODO(TLS1.3): Make sure we have a test to check the consistency of these
115 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL }
116 static const EXTENSION_DEFINITION ext_defs[] = {
118 TLSEXT_TYPE_renegotiate,
119 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
120 | SSL_EXT_SSL3_ALLOWED | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
121 NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
122 tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
126 TLSEXT_TYPE_server_name,
127 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
128 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
130 tls_parse_ctos_server_name, tls_parse_stoc_server_name,
131 tls_construct_stoc_server_name, tls_construct_ctos_server_name,
134 #ifndef OPENSSL_NO_SRP
137 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
138 init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
143 #ifndef OPENSSL_NO_EC
145 TLSEXT_TYPE_ec_point_formats,
146 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
147 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
148 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
149 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
153 TLSEXT_TYPE_supported_groups,
154 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
155 NULL, tls_parse_ctos_supported_groups, NULL,
156 tls_construct_stoc_supported_groups,
157 tls_construct_ctos_supported_groups, NULL
164 TLSEXT_TYPE_session_ticket,
165 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
166 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
167 init_session_ticket, tls_parse_ctos_session_ticket,
168 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
169 tls_construct_ctos_session_ticket, NULL
172 TLSEXT_TYPE_signature_algorithms,
173 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST,
174 init_sig_algs, tls_parse_ctos_sig_algs,
175 tls_parse_ctos_sig_algs, tls_construct_ctos_sig_algs,
176 tls_construct_ctos_sig_algs, final_sig_algs
178 #ifndef OPENSSL_NO_OCSP
180 TLSEXT_TYPE_status_request,
181 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
182 | SSL_EXT_TLS1_3_CERTIFICATE,
183 init_status_request, tls_parse_ctos_status_request,
184 tls_parse_stoc_status_request, tls_construct_stoc_status_request,
185 tls_construct_ctos_status_request, NULL
190 #ifndef OPENSSL_NO_NEXTPROTONEG
192 TLSEXT_TYPE_next_proto_neg,
193 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
194 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
195 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
196 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
203 * Must appear in this list after server_name so that finalisation
204 * happens after server_name callbacks
206 TLSEXT_TYPE_application_layer_protocol_negotiation,
207 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
208 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
209 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
210 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
212 #ifndef OPENSSL_NO_SRTP
214 TLSEXT_TYPE_use_srtp,
215 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
216 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS | SSL_EXT_DTLS_ONLY,
217 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
218 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
224 TLSEXT_TYPE_encrypt_then_mac,
225 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
226 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
227 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
228 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
230 #ifndef OPENSSL_NO_CT
232 TLSEXT_TYPE_signed_certificate_timestamp,
233 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
234 | SSL_EXT_TLS1_3_CERTIFICATE,
237 * No server side support for this, but can be provided by a custom
238 * extension. This is an exception to the rule that custom extensions
239 * cannot override built in ones.
241 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL
247 TLSEXT_TYPE_extended_master_secret,
248 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
249 | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
250 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
251 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
254 TLSEXT_TYPE_supported_versions,
255 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
256 | SSL_EXT_TLS1_3_ONLY,
258 /* Processed inline as part of version selection */
259 NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
262 TLSEXT_TYPE_psk_kex_modes,
263 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
264 | SSL_EXT_TLS1_3_ONLY,
265 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
266 tls_construct_ctos_psk_kex_modes, NULL
268 #ifndef OPENSSL_NO_EC
271 * Must be in this list after supported_groups. We need that to have
272 * been parsed before we do this one.
274 TLSEXT_TYPE_key_share,
275 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
276 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY
277 | SSL_EXT_TLS1_3_ONLY,
278 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
279 tls_construct_stoc_key_share, tls_construct_ctos_key_share,
285 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
286 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
287 NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
292 * Special unsolicited ServerHello extension only used when
293 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
295 TLSEXT_TYPE_cryptopro_bug,
296 SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
297 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
300 TLSEXT_TYPE_early_data,
301 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
302 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
303 NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data,
304 tls_construct_stoc_early_data, tls_construct_ctos_early_data,
308 TLSEXT_TYPE_certificate_authorities,
309 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
310 | SSL_EXT_TLS1_3_ONLY,
311 init_certificate_authorities,
312 tls_parse_certificate_authorities, tls_parse_certificate_authorities,
313 tls_construct_certificate_authorities,
314 tls_construct_certificate_authorities, NULL,
317 /* Must be immediately before pre_shared_key */
319 SSL_EXT_CLIENT_HELLO,
321 /* We send this, but don't read it */
322 NULL, NULL, NULL, tls_construct_ctos_padding, NULL
325 /* Required by the TLSv1.3 spec to always be the last extension */
327 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
328 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
329 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
330 tls_construct_ctos_psk, NULL
334 /* Check whether an extension's context matches the current context */
335 static int validate_context(SSL *s, unsigned int extctx, unsigned int thisctx)
337 /* Check we're allowed to use this extension in this context */
338 if ((thisctx & extctx) == 0)
341 if (SSL_IS_DTLS(s)) {
342 if ((extctx & SSL_EXT_TLS_ONLY) != 0)
344 } else if ((extctx & SSL_EXT_DTLS_ONLY) != 0) {
352 * Verify whether we are allowed to use the extension |type| in the current
353 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
354 * indicate the extension is not allowed. If returning 1 then |*found| is set to
355 * the definition for the extension we found.
357 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
358 custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
359 RAW_EXTENSION **found)
362 size_t builtin_num = OSSL_NELEM(ext_defs);
363 const EXTENSION_DEFINITION *thisext;
365 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
366 if (type == thisext->type) {
367 if (!validate_context(s, thisext->context, context))
370 *found = &rawexlist[i];
375 /* Check the custom extensions */
378 ENDPOINT role = ENDPOINT_BOTH;
379 custom_ext_method *meth = NULL;
381 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
382 role = ENDPOINT_SERVER;
383 else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0)
384 role = ENDPOINT_CLIENT;
386 meth = custom_ext_find(meths, role, type, &offset);
388 if (!validate_context(s, meth->context, context))
390 *found = &rawexlist[offset + builtin_num];
395 /* Unknown extension. We allow it */
401 * Check whether the context defined for an extension |extctx| means whether
402 * the extension is relevant for the current context |thisctx| or not. Returns
403 * 1 if the extension is relevant for this context, and 0 otherwise
405 int extension_is_relevant(SSL *s, unsigned int extctx, unsigned int thisctx)
408 && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
409 || (s->version == SSL3_VERSION
410 && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
412 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
413 || (!SSL_IS_TLS13(s) && (extctx & SSL_EXT_TLS1_3_ONLY) != 0)
414 || (s->hit && (extctx & SSL_EXT_IGNORE_ON_RESUMPTION) != 0))
421 * Gather a list of all the extensions from the data in |packet]. |context|
422 * tells us which message this extension is for. The raw extension data is
423 * stored in |*res| on success. In the event of an error the alert type to use
424 * is stored in |*al|. We don't actually process the content of the extensions
425 * yet, except to check their types. This function also runs the initialiser
426 * functions for all known extensions if |init| is nonzero (whether we have
427 * collected them or not). If successful the caller is responsible for freeing
428 * the contents of |*res|.
430 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
431 * more than one extension of the same type in a ClientHello or ServerHello.
432 * This function returns 1 if all extensions are unique and we have parsed their
433 * types, and 0 if the extensions contain duplicates, could not be successfully
434 * found, or an internal error occurred. We only check duplicates for
435 * extensions that we know about. We ignore others.
437 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
438 RAW_EXTENSION **res, int *al, size_t *len,
441 PACKET extensions = *packet;
444 custom_ext_methods *exts = &s->cert->custext;
445 RAW_EXTENSION *raw_extensions = NULL;
446 const EXTENSION_DEFINITION *thisexd;
451 * Initialise server side custom extensions. Client side is done during
452 * construction of extensions for the ClientHello.
454 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
455 custom_ext_init(&s->cert->custext);
457 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
458 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
459 if (raw_extensions == NULL) {
460 *al = SSL_AD_INTERNAL_ERROR;
461 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
466 while (PACKET_remaining(&extensions) > 0) {
467 unsigned int type, idx;
469 RAW_EXTENSION *thisex;
471 if (!PACKET_get_net_2(&extensions, &type) ||
472 !PACKET_get_length_prefixed_2(&extensions, &extension)) {
473 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
474 *al = SSL_AD_DECODE_ERROR;
478 * Verify this extension is allowed. We only check duplicates for
479 * extensions that we recognise. We also have a special case for the
480 * PSK extension, which must be the last one in the ClientHello.
482 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
483 || (thisex != NULL && thisex->present == 1)
484 || (type == TLSEXT_TYPE_psk
485 && (context & SSL_EXT_CLIENT_HELLO) != 0
486 && PACKET_remaining(&extensions) != 0)) {
487 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
488 *al = SSL_AD_ILLEGAL_PARAMETER;
491 idx = thisex - raw_extensions;
493 * Check that we requested this extension (if appropriate). Requests can
494 * be sent in the ClientHello and CertificateRequest. Unsolicited
495 * extensions can be sent in the NewSessionTicket. We only do this for
496 * the built-in extensions. Custom extensions have a different but
497 * similar check elsewhere.
499 * - The HRR cookie extension is unsolicited
500 * - The renegotiate extension is unsolicited (the client signals
501 * support via an SCSV)
502 * - The signed_certificate_timestamp extension can be provided by a
503 * custom extension or by the built-in version. We let the extension
504 * itself handle unsolicited response checks.
506 if (idx < OSSL_NELEM(ext_defs)
507 && (context & (SSL_EXT_CLIENT_HELLO
508 | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
509 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) == 0
510 && type != TLSEXT_TYPE_cookie
511 && type != TLSEXT_TYPE_renegotiate
512 && type != TLSEXT_TYPE_signed_certificate_timestamp
513 && (s->ext.extflags[idx] & SSL_EXT_FLAG_SENT) == 0) {
514 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_UNSOLICITED_EXTENSION);
515 *al = SSL_AD_UNSUPPORTED_EXTENSION;
518 if (thisex != NULL) {
519 thisex->data = extension;
522 thisex->received_order = i++;
528 * Initialise all known extensions relevant to this context,
529 * whether we have found them or not
531 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs);
533 if (thisexd->init != NULL && (thisexd->context & context) != 0
534 && extension_is_relevant(s, thisexd->context, context)
535 && !thisexd->init(s, context)) {
536 *al = SSL_AD_INTERNAL_ERROR;
542 *res = raw_extensions;
548 OPENSSL_free(raw_extensions);
553 * Runs the parser for a given extension with index |idx|. |exts| contains the
554 * list of all parsed extensions previously collected by
555 * tls_collect_extensions(). The parser is only run if it is applicable for the
556 * given |context| and the parser has not already been run. If this is for a
557 * Certificate message, then we also provide the parser with the relevant
558 * Certificate |x| and its position in the |chainidx| with 0 being the first
559 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
560 * |*al| is populated with a suitable alert code. If an extension is not present
561 * this counted as success.
563 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
564 RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
566 RAW_EXTENSION *currext = &exts[idx];
567 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
568 size_t chainidx, int *al) = NULL;
570 /* Skip if the extension is not present */
571 if (!currext->present)
575 s->ext.debug_cb(s, !s->server, currext->type,
576 PACKET_data(&currext->data),
577 PACKET_remaining(&currext->data),
580 /* Skip if we've already parsed this extension */
586 if (idx < OSSL_NELEM(ext_defs)) {
587 /* We are handling a built-in extension */
588 const EXTENSION_DEFINITION *extdef = &ext_defs[idx];
590 /* Check if extension is defined for our protocol. If not, skip */
591 if (!extension_is_relevant(s, extdef->context, context))
594 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
597 return parser(s, &currext->data, context, x, chainidx, al);
600 * If the parser is NULL we fall through to the custom extension
605 /* Parse custom extensions */
606 if (custom_ext_parse(s, context, currext->type,
607 PACKET_data(&currext->data),
608 PACKET_remaining(&currext->data),
609 x, chainidx, al) <= 0)
616 * Parse all remaining extensions that have not yet been parsed. Also calls the
617 * finalisation for all extensions at the end if |fin| is nonzero, whether we
618 * collected them or not. Returns 1 for success or 0 for failure. If we are
619 * working on a Certificate message then we also pass the Certificate |x| and
620 * its position in the |chainidx|, with 0 being the first certificate. On
621 * failure, |*al| is populated with a suitable alert code.
623 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
624 size_t chainidx, int *al, int fin)
626 size_t i, numexts = OSSL_NELEM(ext_defs);
627 const EXTENSION_DEFINITION *thisexd;
629 /* Calculate the number of extensions in the extensions list */
630 numexts += s->cert->custext.meths_count;
632 /* Parse each extension in turn */
633 for (i = 0; i < numexts; i++) {
634 if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
640 * Finalise all known extensions relevant to this context,
641 * whether we have found them or not
643 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs);
645 if (thisexd->final != NULL && (thisexd->context & context) != 0
646 && !thisexd->final(s, context, exts[i].present, al))
654 int should_add_extension(SSL *s, unsigned int extctx, unsigned int thisctx,
657 /* Skip if not relevant for our context */
658 if ((extctx & thisctx) == 0)
661 /* Check if this extension is defined for our protocol. If not, skip */
662 if ((SSL_IS_DTLS(s) && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
663 || (s->version == SSL3_VERSION
664 && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
666 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
668 && (extctx & SSL_EXT_TLS1_3_ONLY) != 0
669 && (thisctx & SSL_EXT_CLIENT_HELLO) == 0)
670 || ((extctx & SSL_EXT_TLS1_3_ONLY) != 0
671 && (thisctx & SSL_EXT_CLIENT_HELLO) != 0
672 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION)))
679 * Construct all the extensions relevant to the current |context| and write
680 * them to |pkt|. If this is an extension for a Certificate in a Certificate
681 * message, then |x| will be set to the Certificate we are handling, and
682 * |chainidx| will indicate the position in the chainidx we are processing (with
683 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
684 * failure occurs then |al| is populated with a suitable alert code. On a
685 * failure construction stops at the first extension to fail to construct.
687 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
688 X509 *x, size_t chainidx, int *al)
691 int min_version, max_version = 0, reason, tmpal;
692 const EXTENSION_DEFINITION *thisexd;
695 * Normally if something goes wrong during construction it's an internal
696 * error. We can always override this later.
698 tmpal = SSL_AD_INTERNAL_ERROR;
700 if (!WPACKET_start_sub_packet_u16(pkt)
702 * If extensions are of zero length then we don't even add the
703 * extensions length bytes to a ClientHello/ServerHello in SSLv3
706 (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
707 && s->version == SSL3_VERSION
708 && !WPACKET_set_flags(pkt,
709 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
710 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
714 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
715 reason = ssl_get_min_max_version(s, &min_version, &max_version);
717 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
722 /* Add custom extensions first */
723 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
724 /* On the server side with initiase during ClientHello parsing */
725 custom_ext_init(&s->cert->custext);
727 if (!custom_ext_add(s, context, pkt, x, chainidx, max_version, &tmpal)) {
728 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
732 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
733 EXT_RETURN (*construct)(SSL *s, WPACKET *pkt, unsigned int context,
734 X509 *x, size_t chainidx, int *al);
737 /* Skip if not relevant for our context */
738 if (!should_add_extension(s, thisexd->context, context, max_version))
741 construct = s->server ? thisexd->construct_stoc
742 : thisexd->construct_ctos;
744 if (construct == NULL)
747 ret = construct(s, pkt, context, x, chainidx, &tmpal);
748 if (ret == EXT_RETURN_FAIL)
750 if (ret == EXT_RETURN_SENT
751 && (context & (SSL_EXT_CLIENT_HELLO
752 | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
753 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) != 0)
754 s->ext.extflags[i] |= SSL_EXT_FLAG_SENT;
757 if (!WPACKET_close(pkt)) {
758 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
770 * Built in extension finalisation and initialisation functions. All initialise
771 * or finalise the associated extension type for the given |context|. For
772 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
773 * otherwise. These functions return 1 on success or 0 on failure. In the event
774 * of a failure then |*al| is populated with a suitable error code.
777 static int final_renegotiate(SSL *s, unsigned int context, int sent,
782 * Check if we can connect to a server that doesn't support safe
785 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
786 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
788 *al = SSL_AD_HANDSHAKE_FAILURE;
789 SSLerr(SSL_F_FINAL_RENEGOTIATE,
790 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
797 /* Need RI if renegotiating */
799 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
801 *al = SSL_AD_HANDSHAKE_FAILURE;
802 SSLerr(SSL_F_FINAL_RENEGOTIATE,
803 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
811 static int init_server_name(SSL *s, unsigned int context)
814 s->servername_done = 0;
819 static int final_server_name(SSL *s, unsigned int context, int sent,
822 int ret = SSL_TLSEXT_ERR_NOACK;
823 int altmp = SSL_AD_UNRECOGNIZED_NAME;
825 if (s->ctx != NULL && s->ctx->ext.servername_cb != 0)
826 ret = s->ctx->ext.servername_cb(s, &altmp,
827 s->ctx->ext.servername_arg);
828 else if (s->session_ctx != NULL
829 && s->session_ctx->ext.servername_cb != 0)
830 ret = s->session_ctx->ext.servername_cb(s, &altmp,
831 s->session_ctx->ext.servername_arg);
834 case SSL_TLSEXT_ERR_ALERT_FATAL:
838 case SSL_TLSEXT_ERR_ALERT_WARNING:
842 case SSL_TLSEXT_ERR_NOACK:
843 s->servername_done = 0;
851 #ifndef OPENSSL_NO_EC
852 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent,
855 unsigned long alg_k, alg_a;
860 alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
861 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
864 * If we are client and using an elliptic curve cryptography cipher
865 * suite, then if server returns an EC point formats lists extension it
866 * must contain uncompressed.
868 if (s->ext.ecpointformats != NULL
869 && s->ext.ecpointformats_len > 0
870 && s->session->ext.ecpointformats != NULL
871 && s->session->ext.ecpointformats_len > 0
872 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
873 /* we are using an ECC cipher */
875 unsigned char *list = s->session->ext.ecpointformats;
877 for (i = 0; i < s->session->ext.ecpointformats_len; i++) {
878 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed)
881 if (i == s->session->ext.ecpointformats_len) {
882 SSLerr(SSL_F_FINAL_EC_PT_FORMATS,
883 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
892 static int init_session_ticket(SSL *s, unsigned int context)
895 s->ext.ticket_expected = 0;
900 #ifndef OPENSSL_NO_OCSP
901 static int init_status_request(SSL *s, unsigned int context)
904 s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
907 * Ensure we get sensible values passed to tlsext_status_cb in the event
908 * that we don't receive a status message
910 OPENSSL_free(s->ext.ocsp.resp);
911 s->ext.ocsp.resp = NULL;
912 s->ext.ocsp.resp_len = 0;
919 #ifndef OPENSSL_NO_NEXTPROTONEG
920 static int init_npn(SSL *s, unsigned int context)
928 static int init_alpn(SSL *s, unsigned int context)
930 OPENSSL_free(s->s3->alpn_selected);
931 s->s3->alpn_selected = NULL;
932 s->s3->alpn_selected_len = 0;
934 OPENSSL_free(s->s3->alpn_proposed);
935 s->s3->alpn_proposed = NULL;
936 s->s3->alpn_proposed_len = 0;
941 static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
943 const unsigned char *selected = NULL;
944 unsigned char selected_len = 0;
949 if (s->ctx->ext.alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
950 int r = s->ctx->ext.alpn_select_cb(s, &selected, &selected_len,
951 s->s3->alpn_proposed,
952 (unsigned int)s->s3->alpn_proposed_len,
953 s->ctx->ext.alpn_select_cb_arg);
955 if (r == SSL_TLSEXT_ERR_OK) {
956 OPENSSL_free(s->s3->alpn_selected);
957 s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
958 if (s->s3->alpn_selected == NULL) {
959 *al = SSL_AD_INTERNAL_ERROR;
962 s->s3->alpn_selected_len = selected_len;
963 #ifndef OPENSSL_NO_NEXTPROTONEG
964 /* ALPN takes precedence over NPN. */
967 } else if (r == SSL_TLSEXT_ERR_NOACK) {
968 /* Behave as if no callback was present. */
971 *al = SSL_AD_NO_APPLICATION_PROTOCOL;
979 static int init_sig_algs(SSL *s, unsigned int context)
981 /* Clear any signature algorithms extension received */
982 OPENSSL_free(s->s3->tmp.peer_sigalgs);
983 s->s3->tmp.peer_sigalgs = NULL;
988 #ifndef OPENSSL_NO_SRP
989 static int init_srp(SSL *s, unsigned int context)
991 OPENSSL_free(s->srp_ctx.login);
992 s->srp_ctx.login = NULL;
998 static int init_etm(SSL *s, unsigned int context)
1005 static int init_ems(SSL *s, unsigned int context)
1008 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
1013 static int final_ems(SSL *s, unsigned int context, int sent, int *al)
1015 if (!s->server && s->hit) {
1017 * Check extended master secret extension is consistent with
1020 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
1021 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
1022 *al = SSL_AD_HANDSHAKE_FAILURE;
1023 SSLerr(SSL_F_FINAL_EMS, SSL_R_INCONSISTENT_EXTMS);
1031 static int init_certificate_authorities(SSL *s, unsigned int context)
1033 sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free);
1034 s->s3->tmp.peer_ca_names = NULL;
1038 static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
1039 unsigned int context,
1044 const STACK_OF(X509_NAME) *ca_sk = SSL_get0_CA_list(s);
1046 if (ca_sk == NULL || sk_X509_NAME_num(ca_sk) == 0)
1047 return EXT_RETURN_NOT_SENT;
1049 if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_certificate_authorities)
1050 || !WPACKET_start_sub_packet_u16(pkt)
1051 || !construct_ca_names(s, pkt)
1052 || !WPACKET_close(pkt)) {
1053 SSLerr(SSL_F_TLS_CONSTRUCT_CERTIFICATE_AUTHORITIES,
1054 ERR_R_INTERNAL_ERROR);
1055 return EXT_RETURN_FAIL;
1058 return EXT_RETURN_SENT;
1061 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
1062 unsigned int context, X509 *x,
1063 size_t chainidx, int *al)
1065 if (!parse_ca_names(s, pkt, al))
1067 if (PACKET_remaining(pkt) != 0) {
1068 *al = SSL_AD_DECODE_ERROR;
1074 #ifndef OPENSSL_NO_SRTP
1075 static int init_srtp(SSL *s, unsigned int context)
1078 s->srtp_profile = NULL;
1084 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
1086 if (!sent && SSL_IS_TLS13(s) && !s->hit) {
1087 *al = TLS13_AD_MISSING_EXTENSION;
1088 SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
1095 #ifndef OPENSSL_NO_EC
1096 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
1098 if (!SSL_IS_TLS13(s))
1101 /* Nothing to do for key_share in an HRR */
1102 if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0)
1109 * we have no key_share
1111 * (we are not resuming
1112 * OR the kex_mode doesn't allow non key_share resumes)
1119 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
1120 /* Nothing left we can do - just fail */
1121 *al = SSL_AD_MISSING_EXTENSION;
1122 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1129 * we have no key_share
1132 * we didn't already send a HelloRetryRequest
1134 * the client sent a key_share extension
1136 * (we are not resuming
1137 * OR the kex_mode allows key_share resumes)
1139 * a shared group exists
1141 * send a HelloRetryRequest
1143 * we are not resuming
1145 * the kex_mode doesn't allow non key_share resumes
1149 if (s->server && s->s3->peer_tmp == NULL) {
1150 /* No suitable share */
1151 if (s->hello_retry_request == 0 && sent
1153 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
1155 const unsigned char *pcurves, *pcurvestmp, *clntcurves;
1156 size_t num_curves, clnt_num_curves, i;
1157 unsigned int group_id = 0;
1159 /* Check if a shared group exists */
1161 /* Get the clients list of supported groups. */
1162 if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
1163 *al = SSL_AD_INTERNAL_ERROR;
1164 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1168 /* Get our list of available groups */
1169 if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
1170 *al = SSL_AD_INTERNAL_ERROR;
1171 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1175 /* Find the first group we allow that is also in client's list */
1176 for (i = 0, pcurvestmp = pcurves; i < num_curves;
1177 i++, pcurvestmp += 2) {
1178 group_id = bytestogroup(pcurvestmp);
1180 if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
1184 if (i < num_curves) {
1185 /* A shared group exists so send a HelloRetryRequest */
1186 s->s3->group_id = group_id;
1187 s->hello_retry_request = 1;
1192 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
1193 /* Nothing left we can do - just fail */
1195 *al = SSL_AD_MISSING_EXTENSION;
1197 *al = SSL_AD_HANDSHAKE_FAILURE;
1198 SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
1203 /* We have a key_share so don't send any more HelloRetryRequest messages */
1205 s->hello_retry_request = 0;
1208 * For a client side resumption with no key_share we need to generate
1209 * the handshake secret (otherwise this is done during key_share
1212 if (!sent && !s->server && !tls13_generate_handshake_secret(s, NULL, 0)) {
1213 *al = SSL_AD_INTERNAL_ERROR;
1214 SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
1222 static int init_psk_kex_modes(SSL *s, unsigned int context)
1224 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE;
1228 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
1229 size_t binderoffset, const unsigned char *binderin,
1230 unsigned char *binderout, SSL_SESSION *sess, int sign,
1233 EVP_PKEY *mackey = NULL;
1234 EVP_MD_CTX *mctx = NULL;
1235 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
1236 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
1237 unsigned char *early_secret;
1238 const char resumption_label[] = "res binder";
1239 const char external_label[] = "ext binder";
1241 size_t bindersize, labelsize, hashsize = EVP_MD_size(md);
1245 label = external_label;
1246 labelsize = sizeof(external_label) - 1;
1248 label = resumption_label;
1249 labelsize = sizeof(resumption_label) - 1;
1253 * Generate the early_secret. On the server side we've selected a PSK to
1254 * resume with (internal or external) so we always do this. On the client
1255 * side we do this for a non-external (i.e. resumption) PSK so that it
1256 * is in place for sending early data. For client side external PSK we
1257 * generate it but store it away for later use.
1259 if (s->server || !external)
1260 early_secret = (unsigned char *)s->early_secret;
1262 early_secret = (unsigned char *)sess->early_secret;
1263 if (!tls13_generate_secret(s, md, NULL, sess->master_key,
1264 sess->master_key_length, early_secret)) {
1265 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1270 * Create the handshake hash for the binder key...the messages so far are
1273 mctx = EVP_MD_CTX_new();
1275 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
1276 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1277 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1281 /* Generate the binder key */
1282 if (!tls13_hkdf_expand(s, md, early_secret, (unsigned char *)label,
1283 labelsize, hash, hashsize, binderkey, hashsize)) {
1284 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1288 /* Generate the finished key */
1289 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) {
1290 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1294 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
1295 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1300 * Get a hash of the ClientHello up to the start of the binders. If we are
1301 * following a HelloRetryRequest then this includes the hash of the first
1302 * ClientHello and the HelloRetryRequest itself.
1304 if (s->hello_retry_request) {
1308 hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
1309 if (hdatalen <= 0) {
1310 SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
1315 * For servers the handshake buffer data will include the second
1316 * ClientHello - which we don't want - so we need to take that bit off.
1319 PACKET hashprefix, msg;
1321 /* Find how many bytes are left after the first two messages */
1322 if (!PACKET_buf_init(&hashprefix, hdata, hdatalen)
1323 || !PACKET_forward(&hashprefix, 1)
1324 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)
1325 || !PACKET_forward(&hashprefix, 1)
1326 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) {
1327 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1330 hdatalen -= PACKET_remaining(&hashprefix);
1333 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
1334 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1339 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
1340 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
1341 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1345 mackey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, finishedkey, hashsize);
1346 if (mackey == NULL) {
1347 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1352 binderout = tmpbinder;
1354 bindersize = hashsize;
1355 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0
1356 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0
1357 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0
1358 || bindersize != hashsize) {
1359 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
1366 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1367 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0);
1371 OPENSSL_cleanse(binderkey, sizeof(binderkey));
1372 OPENSSL_cleanse(finishedkey, sizeof(finishedkey));
1373 EVP_PKEY_free(mackey);
1374 EVP_MD_CTX_free(mctx);
1379 static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
1381 if (!s->server || !sent)
1384 if (s->max_early_data == 0
1386 || s->session->ext.tick_identity != 0
1387 || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
1388 || !s->ext.early_data_ok
1389 || s->hello_retry_request
1390 || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
1391 || (s->s3->alpn_selected_len > 0
1392 && memcmp(s->s3->alpn_selected, s->session->ext.alpn_selected,
1393 s->s3->alpn_selected_len) != 0)) {
1394 s->ext.early_data = SSL_EARLY_DATA_REJECTED;
1396 s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
1398 if (!tls13_change_cipher_state(s,
1399 SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
1400 *al = SSL_AD_INTERNAL_ERROR;