2 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #include "../ssl_locl.h"
11 #include "statem_locl.h"
13 static int final_renegotiate(SSL
*s
, unsigned int context
, int sent
,
15 static int init_server_name(SSL
*s
, unsigned int context
);
16 static int final_server_name(SSL
*s
, unsigned int context
, int sent
,
19 static int final_ec_pt_formats(SSL
*s
, unsigned int context
, int sent
,
22 static int init_session_ticket(SSL
*s
, unsigned int context
);
23 #ifndef OPENSSL_NO_OCSP
24 static int init_status_request(SSL
*s
, unsigned int context
);
26 #ifndef OPENSSL_NO_NEXTPROTONEG
27 static int init_npn(SSL
*s
, unsigned int context
);
29 static int init_alpn(SSL
*s
, unsigned int context
);
30 static int final_alpn(SSL
*s
, unsigned int context
, int sent
, int *al
);
31 static int init_sig_algs(SSL
*s
, unsigned int context
);
32 #ifndef OPENSSL_NO_SRP
33 static int init_srp(SSL
*s
, unsigned int context
);
35 static int init_etm(SSL
*s
, unsigned int context
);
36 static int init_ems(SSL
*s
, unsigned int context
);
37 static int final_ems(SSL
*s
, unsigned int context
, int sent
, int *al
);
38 static int init_psk_kex_modes(SSL
*s
, unsigned int context
);
39 static int final_key_share(SSL
*s
, unsigned int context
, int sent
, int *al
);
40 #ifndef OPENSSL_NO_SRTP
41 static int init_srtp(SSL
*s
, unsigned int context
);
43 static int final_sig_algs(SSL
*s
, unsigned int context
, int sent
, int *al
);
45 /* Structure to define a built-in extension */
46 typedef struct extensions_definition_st
{
47 /* The defined type for the extension */
50 * The context that this extension applies to, e.g. what messages and
55 * Initialise extension before parsing. Always called for relevant contexts
56 * even if extension not present
58 int (*init
)(SSL
*s
, unsigned int context
);
59 /* Parse extension sent from client to server */
60 int (*parse_ctos
)(SSL
*s
, PACKET
*pkt
, X509
*x
, size_t chainidx
, int *al
);
61 /* Parse extension send from server to client */
62 int (*parse_stoc
)(SSL
*s
, PACKET
*pkt
, X509
*x
, size_t chainidx
, int *al
);
63 /* Construct extension sent from server to client */
64 int (*construct_stoc
)(SSL
*s
, WPACKET
*pkt
, X509
*x
, size_t chainidx
,
66 /* Construct extension sent from client to server */
67 int (*construct_ctos
)(SSL
*s
, WPACKET
*pkt
, X509
*x
, size_t chainidx
,
70 * Finalise extension after parsing. Always called where an extensions was
71 * initialised even if the extension was not present. |sent| is set to 1 if
72 * the extension was seen, or 0 otherwise.
74 int (*final
)(SSL
*s
, unsigned int context
, int sent
, int *al
);
75 } EXTENSION_DEFINITION
;
78 * Definitions of all built-in extensions. NOTE: Changes in the number or order
79 * of these extensions should be mirrored with equivalent changes to the
80 * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
81 * Each extension has an initialiser, a client and
82 * server side parser and a finaliser. The initialiser is called (if the
83 * extension is relevant to the given context) even if we did not see the
84 * extension in the message that we received. The parser functions are only
85 * called if we see the extension in the message. The finalisers are always
86 * called if the initialiser was called.
87 * There are also server and client side constructor functions which are always
88 * called during message construction if the extension is relevant for the
90 * The initialisation, parsing, finalisation and construction functions are
91 * always called in the order defined in this list. Some extensions may depend
92 * on others having been processed first, so the order of this list is
94 * The extension context is defined by a series of flags which specify which
95 * messages the extension is relevant to. These flags also specify whether the
96 * extension is relevant to a particular protocol or protocol version.
98 * TODO(TLS1.3): Make sure we have a test to check the consistency of these
100 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL }
101 static const EXTENSION_DEFINITION ext_defs
[] = {
103 TLSEXT_TYPE_renegotiate
,
104 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
| EXT_SSL3_ALLOWED
105 | EXT_TLS1_2_AND_BELOW_ONLY
,
106 NULL
, tls_parse_ctos_renegotiate
, tls_parse_stoc_renegotiate
,
107 tls_construct_stoc_renegotiate
, tls_construct_ctos_renegotiate
,
111 TLSEXT_TYPE_server_name
,
112 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
113 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS
,
115 tls_parse_ctos_server_name
, tls_parse_stoc_server_name
,
116 tls_construct_stoc_server_name
, tls_construct_ctos_server_name
,
119 #ifndef OPENSSL_NO_SRP
122 EXT_CLIENT_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
123 init_srp
, tls_parse_ctos_srp
, NULL
, NULL
, tls_construct_ctos_srp
, NULL
128 #ifndef OPENSSL_NO_EC
130 TLSEXT_TYPE_ec_point_formats
,
131 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
132 NULL
, tls_parse_ctos_ec_pt_formats
, tls_parse_stoc_ec_pt_formats
,
133 tls_construct_stoc_ec_pt_formats
, tls_construct_ctos_ec_pt_formats
,
137 TLSEXT_TYPE_supported_groups
,
138 EXT_CLIENT_HELLO
| EXT_TLS1_3_ENCRYPTED_EXTENSIONS
,
139 NULL
, tls_parse_ctos_supported_groups
, NULL
,
140 NULL
/* TODO(TLS1.3): Need to add this */,
141 tls_construct_ctos_supported_groups
, NULL
148 TLSEXT_TYPE_session_ticket
,
149 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
150 init_session_ticket
, tls_parse_ctos_session_ticket
,
151 tls_parse_stoc_session_ticket
, tls_construct_stoc_session_ticket
,
152 tls_construct_ctos_session_ticket
, NULL
155 TLSEXT_TYPE_signature_algorithms
,
157 init_sig_algs
, tls_parse_ctos_sig_algs
, NULL
, NULL
,
158 tls_construct_ctos_sig_algs
, final_sig_algs
160 #ifndef OPENSSL_NO_OCSP
162 TLSEXT_TYPE_status_request
,
163 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
164 | EXT_TLS1_3_CERTIFICATE
,
165 init_status_request
, tls_parse_ctos_status_request
,
166 tls_parse_stoc_status_request
, tls_construct_stoc_status_request
,
167 tls_construct_ctos_status_request
, NULL
172 #ifndef OPENSSL_NO_NEXTPROTONEG
174 TLSEXT_TYPE_next_proto_neg
,
175 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
176 init_npn
, tls_parse_ctos_npn
, tls_parse_stoc_npn
,
177 tls_construct_stoc_next_proto_neg
, tls_construct_ctos_npn
, NULL
184 * Must appear in this list after server_name so that finalisation
185 * happens after server_name callbacks
187 TLSEXT_TYPE_application_layer_protocol_negotiation
,
188 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
189 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS
,
190 init_alpn
, tls_parse_ctos_alpn
, tls_parse_stoc_alpn
,
191 tls_construct_stoc_alpn
, tls_construct_ctos_alpn
, final_alpn
193 #ifndef OPENSSL_NO_SRTP
195 TLSEXT_TYPE_use_srtp
,
196 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
197 | EXT_TLS1_3_ENCRYPTED_EXTENSIONS
| EXT_DTLS_ONLY
,
198 init_srtp
, tls_parse_ctos_use_srtp
, tls_parse_stoc_use_srtp
,
199 tls_construct_stoc_use_srtp
, tls_construct_ctos_use_srtp
, NULL
205 TLSEXT_TYPE_encrypt_then_mac
,
206 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
207 init_etm
, tls_parse_ctos_etm
, tls_parse_stoc_etm
,
208 tls_construct_stoc_etm
, tls_construct_ctos_etm
, NULL
210 #ifndef OPENSSL_NO_CT
212 TLSEXT_TYPE_signed_certificate_timestamp
,
213 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
214 | EXT_TLS1_3_CERTIFICATE
,
217 * No server side support for this, but can be provided by a custom
218 * extension. This is an exception to the rule that custom extensions
219 * cannot override built in ones.
221 NULL
, tls_parse_stoc_sct
, NULL
, tls_construct_ctos_sct
, NULL
227 TLSEXT_TYPE_extended_master_secret
,
228 EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
229 init_ems
, tls_parse_ctos_ems
, tls_parse_stoc_ems
,
230 tls_construct_stoc_ems
, tls_construct_ctos_ems
, final_ems
233 TLSEXT_TYPE_supported_versions
,
234 EXT_CLIENT_HELLO
| EXT_TLS_IMPLEMENTATION_ONLY
| EXT_TLS1_3_ONLY
,
236 /* Processed inline as part of version selection */
237 NULL
, NULL
, NULL
, tls_construct_ctos_supported_versions
, NULL
240 /* Must be before key_share */
241 TLSEXT_TYPE_psk_kex_modes
,
242 EXT_CLIENT_HELLO
| EXT_TLS_IMPLEMENTATION_ONLY
| EXT_TLS1_3_ONLY
,
243 init_psk_kex_modes
, tls_parse_ctos_psk_kex_modes
, NULL
, NULL
,
244 tls_construct_ctos_psk_kex_modes
, NULL
248 * Must be in this list after supported_groups. We need that to have
249 * been parsed before we do this one.
251 TLSEXT_TYPE_key_share
,
252 EXT_CLIENT_HELLO
| EXT_TLS1_3_SERVER_HELLO
253 | EXT_TLS1_3_HELLO_RETRY_REQUEST
| EXT_TLS_IMPLEMENTATION_ONLY
255 NULL
, tls_parse_ctos_key_share
, tls_parse_stoc_key_share
,
256 tls_construct_stoc_key_share
, tls_construct_ctos_key_share
,
261 * Special unsolicited ServerHello extension only used when
262 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
264 TLSEXT_TYPE_cryptopro_bug
,
265 EXT_TLS1_2_SERVER_HELLO
| EXT_TLS1_2_AND_BELOW_ONLY
,
266 NULL
, NULL
, NULL
, tls_construct_stoc_cryptopro_bug
, NULL
, NULL
269 /* Must be immediately before pre_shared_key */
270 /* TODO(TLS1.3): Fix me */
274 /* We send this, but don't read it */
275 NULL
, NULL
, NULL
, tls_construct_ctos_padding
, NULL
278 /* Required by the TLSv1.3 spec to always be the last extension */
280 EXT_CLIENT_HELLO
| EXT_TLS1_3_SERVER_HELLO
| EXT_TLS_IMPLEMENTATION_ONLY
282 NULL
, tls_parse_ctos_psk
, tls_parse_stoc_psk
, tls_construct_stoc_psk
,
283 tls_construct_ctos_psk
, NULL
288 * Verify whether we are allowed to use the extension |type| in the current
289 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
290 * indicate the extension is not allowed. If returning 1 then |*found| is set to
291 * 1 if we found a definition for the extension, and |*idx| is set to its index
293 static int verify_extension(SSL
*s
, unsigned int context
, unsigned int type
,
294 custom_ext_methods
*meths
, RAW_EXTENSION
*rawexlist
,
295 RAW_EXTENSION
**found
)
298 size_t builtin_num
= OSSL_NELEM(ext_defs
);
299 const EXTENSION_DEFINITION
*thisext
;
301 for (i
= 0, thisext
= ext_defs
; i
< builtin_num
; i
++, thisext
++) {
302 if (type
== thisext
->type
) {
303 /* Check we're allowed to use this extension in this context */
304 if ((context
& thisext
->context
) == 0)
307 if (SSL_IS_DTLS(s
)) {
308 if ((thisext
->context
& EXT_TLS_ONLY
) != 0)
310 } else if ((thisext
->context
& EXT_DTLS_ONLY
) != 0) {
314 *found
= &rawexlist
[i
];
319 if ((context
& (EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
)) == 0) {
321 * Custom extensions only apply to <=TLS1.2. This extension is unknown
322 * in this context - we allow it
328 /* Check the custom extensions */
330 for (i
= builtin_num
; i
< builtin_num
+ meths
->meths_count
; i
++) {
331 if (meths
->meths
[i
- builtin_num
].ext_type
== type
) {
332 *found
= &rawexlist
[i
];
338 /* Unknown extension. We allow it */
344 * Check whether the context defined for an extension |extctx| means whether
345 * the extension is relevant for the current context |thisctx| or not. Returns
346 * 1 if the extension is relevant for this context, and 0 otherwise
348 static int extension_is_relevant(SSL
*s
, unsigned int extctx
,
349 unsigned int thisctx
)
352 && (extctx
& EXT_TLS_IMPLEMENTATION_ONLY
) != 0)
353 || (s
->version
== SSL3_VERSION
354 && (extctx
& EXT_SSL3_ALLOWED
) == 0)
356 && (extctx
& EXT_TLS1_2_AND_BELOW_ONLY
) != 0)
357 || (!SSL_IS_TLS13(s
) && (extctx
& EXT_TLS1_3_ONLY
) != 0))
364 * Gather a list of all the extensions from the data in |packet]. |context|
365 * tells us which message this extension is for. The raw extension data is
366 * stored in |*res| on success. In the event of an error the alert type to use
367 * is stored in |*al|. We don't actually process the content of the extensions
368 * yet, except to check their types. This function also runs the initialiser
369 * functions for all known extensions (whether we have collected them or not).
370 * If successful the caller is responsible for freeing the contents of |*res|.
372 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
373 * more than one extension of the same type in a ClientHello or ServerHello.
374 * This function returns 1 if all extensions are unique and we have parsed their
375 * types, and 0 if the extensions contain duplicates, could not be successfully
376 * found, or an internal error occurred. We only check duplicates for
377 * extensions that we know about. We ignore others.
379 int tls_collect_extensions(SSL
*s
, PACKET
*packet
, unsigned int context
,
380 RAW_EXTENSION
**res
, int *al
)
382 PACKET extensions
= *packet
;
384 custom_ext_methods
*exts
= NULL
;
385 RAW_EXTENSION
*raw_extensions
= NULL
;
386 const EXTENSION_DEFINITION
*thisexd
;
391 * Initialise server side custom extensions. Client side is done during
392 * construction of extensions for the ClientHello.
394 if ((context
& EXT_CLIENT_HELLO
) != 0) {
395 exts
= &s
->cert
->srv_ext
;
396 custom_ext_init(&s
->cert
->srv_ext
);
397 } else if ((context
& EXT_TLS1_2_SERVER_HELLO
) != 0) {
398 exts
= &s
->cert
->cli_ext
;
401 raw_extensions
= OPENSSL_zalloc((OSSL_NELEM(ext_defs
)
402 + (exts
!= NULL
? exts
->meths_count
: 0))
403 * sizeof(*raw_extensions
));
404 if (raw_extensions
== NULL
) {
405 *al
= SSL_AD_INTERNAL_ERROR
;
406 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS
, ERR_R_MALLOC_FAILURE
);
410 while (PACKET_remaining(&extensions
) > 0) {
413 RAW_EXTENSION
*thisex
;
415 if (!PACKET_get_net_2(&extensions
, &type
) ||
416 !PACKET_get_length_prefixed_2(&extensions
, &extension
)) {
417 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS
, SSL_R_BAD_EXTENSION
);
418 *al
= SSL_AD_DECODE_ERROR
;
422 * Verify this extension is allowed. We only check duplicates for
423 * extensions that we recognise.
425 if (!verify_extension(s
, context
, type
, exts
, raw_extensions
, &thisex
)
426 || (thisex
!= NULL
&& thisex
->present
== 1)) {
427 SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS
, SSL_R_BAD_EXTENSION
);
428 *al
= SSL_AD_ILLEGAL_PARAMETER
;
431 if (thisex
!= NULL
) {
432 thisex
->data
= extension
;
439 * Initialise all known extensions relevant to this context, whether we have
442 for (thisexd
= ext_defs
, i
= 0; i
< OSSL_NELEM(ext_defs
); i
++, thisexd
++) {
443 if(thisexd
->init
!= NULL
&& (thisexd
->context
& context
) != 0
444 && extension_is_relevant(s
, thisexd
->context
, context
)
445 && !thisexd
->init(s
, context
)) {
446 *al
= SSL_AD_INTERNAL_ERROR
;
451 *res
= raw_extensions
;
455 OPENSSL_free(raw_extensions
);
460 * Runs the parser for a given extension with index |idx|. |exts| contains the
461 * list of all parsed extensions previously collected by
462 * tls_collect_extensions(). The parser is only run if it is applicable for the
463 * given |context| and the parser has not already been run. If this is for a
464 * Certificate message, then we also provide the parser with the relevant
465 * Certificate |x| and its position in the |chainidx| with 0 being the first
466 * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
467 * |*al| is populated with a suitable alert code. If an extension is not present
468 * this counted as success.
470 int tls_parse_extension(SSL
*s
, TLSEXT_INDEX idx
, int context
,
471 RAW_EXTENSION
*exts
, X509
*x
, size_t chainidx
, int *al
)
473 RAW_EXTENSION
*currext
= &exts
[idx
];
474 int (*parser
)(SSL
*s
, PACKET
*pkt
, X509
*x
, size_t chainidx
, int *al
) = NULL
;
476 /* Skip if the extension is not present */
477 if (!currext
->present
)
481 s
->ext
.debug_cb(s
, !s
->server
, currext
->type
,
482 PACKET_data(&currext
->data
),
483 PACKET_remaining(&currext
->data
),
486 /* Skip if we've already parsed this extension */
492 if (idx
< OSSL_NELEM(ext_defs
)) {
493 /* We are handling a built-in extension */
494 const EXTENSION_DEFINITION
*extdef
= &ext_defs
[idx
];
496 /* Check if extension is defined for our protocol. If not, skip */
497 if (!extension_is_relevant(s
, extdef
->context
, context
))
500 parser
= s
->server
? extdef
->parse_ctos
: extdef
->parse_stoc
;
503 return parser(s
, &currext
->data
, x
, chainidx
, al
);
506 * If the parser is NULL we fall through to the custom extension
512 * This is a custom extension. We only allow this if it is a non
513 * resumed session on the server side.
515 * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
516 * We're going to need a new mechanism for TLS1.3 to specify which
517 * messages to add the custom extensions to.
519 if ((!s
->hit
|| !s
->server
)
521 & (EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
)) != 0
522 && custom_ext_parse(s
, s
->server
, currext
->type
,
523 PACKET_data(&currext
->data
),
524 PACKET_remaining(&currext
->data
),
532 * Parse all remaining extensions that have not yet been parsed. Also calls the
533 * finalisation for all extensions at the end, whether we collected them or not.
534 * Returns 1 for success or 0 for failure. If we are working on a Certificate
535 * message then we also pass the Certificate |x| and its position in the
536 * |chainidx|, with 0 being the first certificate. On failure, |*al| is
537 * populated with a suitable alert code.
539 int tls_parse_all_extensions(SSL
*s
, int context
, RAW_EXTENSION
*exts
, X509
*x
,
540 size_t chainidx
, int *al
)
542 size_t i
, numexts
= OSSL_NELEM(ext_defs
);
543 const EXTENSION_DEFINITION
*thisexd
;
545 /* Calculate the number of extensions in the extensions list */
546 if ((context
& EXT_CLIENT_HELLO
) != 0) {
547 numexts
+= s
->cert
->srv_ext
.meths_count
;
548 } else if ((context
& EXT_TLS1_2_SERVER_HELLO
) != 0) {
549 numexts
+= s
->cert
->cli_ext
.meths_count
;
552 /* Parse each extension in turn */
553 for (i
= 0; i
< numexts
; i
++) {
554 if (!tls_parse_extension(s
, i
, context
, exts
, x
, chainidx
, al
))
559 * Finalise all known extensions relevant to this context, whether we have
562 for (i
= 0, thisexd
= ext_defs
; i
< OSSL_NELEM(ext_defs
); i
++, thisexd
++) {
563 if(thisexd
->final
!= NULL
564 && (thisexd
->context
& context
) != 0
565 && !thisexd
->final(s
, context
, exts
[i
].present
, al
))
573 * Construct all the extensions relevant to the current |context| and write
574 * them to |pkt|. If this is an extension for a Certificate in a Certificate
575 * message, then |x| will be set to the Certificate we are handling, and
576 * |chainidx| will indicate the position in the chainidx we are processing (with
577 * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
578 * failure occurs then |al| is populated with a suitable alert code. On a
579 * failure construction stops at the first extension to fail to construct.
581 int tls_construct_extensions(SSL
*s
, WPACKET
*pkt
, unsigned int context
,
582 X509
*x
, size_t chainidx
, int *al
)
585 int addcustom
= 0, min_version
, max_version
= 0, reason
, tmpal
;
586 const EXTENSION_DEFINITION
*thisexd
;
589 * Normally if something goes wrong during construction it's an internal
590 * error. We can always override this later.
592 tmpal
= SSL_AD_INTERNAL_ERROR
;
594 if (!WPACKET_start_sub_packet_u16(pkt
)
596 * If extensions are of zero length then we don't even add the
597 * extensions length bytes to a ClientHello/ServerHello in SSLv3
599 || ((context
& (EXT_CLIENT_HELLO
| EXT_TLS1_2_SERVER_HELLO
)) != 0
600 && s
->version
== SSL3_VERSION
601 && !WPACKET_set_flags(pkt
,
602 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH
))) {
603 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS
, ERR_R_INTERNAL_ERROR
);
607 if ((context
& EXT_CLIENT_HELLO
) != 0) {
608 reason
= ssl_get_client_min_max_version(s
, &min_version
, &max_version
);
610 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS
, reason
);
615 /* Add custom extensions first */
616 if ((context
& EXT_CLIENT_HELLO
) != 0) {
617 custom_ext_init(&s
->cert
->cli_ext
);
619 } else if ((context
& EXT_TLS1_2_SERVER_HELLO
) != 0) {
621 * We already initialised the custom extensions during ClientHello
624 * TODO(TLS1.3): We're going to need a new custom extension mechanism
625 * for TLS1.3, so that custom extensions can specify which of the
626 * multiple message they wish to add themselves to.
631 if (addcustom
&& !custom_ext_add(s
, s
->server
, pkt
, &tmpal
)) {
632 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS
, ERR_R_INTERNAL_ERROR
);
636 for (i
= 0, thisexd
= ext_defs
; i
< OSSL_NELEM(ext_defs
); i
++, thisexd
++) {
637 int (*construct
)(SSL
*s
, WPACKET
*pkt
, X509
*x
, size_t chainidx
,
640 /* Skip if not relevant for our context */
641 if ((thisexd
->context
& context
) == 0)
644 construct
= s
->server
? thisexd
->construct_stoc
645 : thisexd
->construct_ctos
;
647 /* Check if this extension is defined for our protocol. If not, skip */
649 && (thisexd
->context
& EXT_TLS_IMPLEMENTATION_ONLY
)
651 || (s
->version
== SSL3_VERSION
652 && (thisexd
->context
& EXT_SSL3_ALLOWED
) == 0)
654 && (thisexd
->context
& EXT_TLS1_2_AND_BELOW_ONLY
)
657 && (thisexd
->context
& EXT_TLS1_3_ONLY
) != 0
658 && (context
& EXT_CLIENT_HELLO
) == 0)
659 || ((thisexd
->context
& EXT_TLS1_3_ONLY
) != 0
660 && (context
& EXT_CLIENT_HELLO
) != 0
661 && (SSL_IS_DTLS(s
) || max_version
< TLS1_3_VERSION
))
662 || construct
== NULL
)
665 if (!construct(s
, pkt
, x
, chainidx
, &tmpal
))
669 if (!WPACKET_close(pkt
)) {
670 SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS
, ERR_R_INTERNAL_ERROR
);
682 * Built in extension finalisation and initialisation functions. All initialise
683 * or finalise the associated extension type for the given |context|. For
684 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0
685 * otherwise. These functions return 1 on success or 0 on failure. In the event
686 * of a failure then |*al| is populated with a suitable error code.
689 static int final_renegotiate(SSL
*s
, unsigned int context
, int sent
,
694 * Check if we can connect to a server that doesn't support safe
697 if (!(s
->options
& SSL_OP_LEGACY_SERVER_CONNECT
)
698 && !(s
->options
& SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
)
700 *al
= SSL_AD_HANDSHAKE_FAILURE
;
701 SSLerr(SSL_F_FINAL_RENEGOTIATE
,
702 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED
);
709 /* Need RI if renegotiating */
711 && !(s
->options
& SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
)
713 *al
= SSL_AD_HANDSHAKE_FAILURE
;
714 SSLerr(SSL_F_FINAL_RENEGOTIATE
,
715 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED
);
723 static int init_server_name(SSL
*s
, unsigned int context
)
726 s
->servername_done
= 0;
731 static int final_server_name(SSL
*s
, unsigned int context
, int sent
,
734 int ret
= SSL_TLSEXT_ERR_NOACK
;
735 int altmp
= SSL_AD_UNRECOGNIZED_NAME
;
737 if (s
->ctx
!= NULL
&& s
->ctx
->ext
.servername_cb
!= 0)
738 ret
= s
->ctx
->ext
.servername_cb(s
, &altmp
,
739 s
->ctx
->ext
.servername_arg
);
740 else if (s
->initial_ctx
!= NULL
741 && s
->initial_ctx
->ext
.servername_cb
!= 0)
742 ret
= s
->initial_ctx
->ext
.servername_cb(s
, &altmp
,
743 s
->initial_ctx
->ext
.servername_arg
);
746 case SSL_TLSEXT_ERR_ALERT_FATAL
:
750 case SSL_TLSEXT_ERR_ALERT_WARNING
:
754 case SSL_TLSEXT_ERR_NOACK
:
755 s
->servername_done
= 0;
763 #ifndef OPENSSL_NO_EC
764 static int final_ec_pt_formats(SSL
*s
, unsigned int context
, int sent
,
767 unsigned long alg_k
, alg_a
;
772 alg_k
= s
->s3
->tmp
.new_cipher
->algorithm_mkey
;
773 alg_a
= s
->s3
->tmp
.new_cipher
->algorithm_auth
;
776 * If we are client and using an elliptic curve cryptography cipher
777 * suite, then if server returns an EC point formats lists extension it
778 * must contain uncompressed.
780 if (s
->ext
.ecpointformats
!= NULL
781 && s
->ext
.ecpointformats_len
> 0
782 && s
->session
->ext
.ecpointformats
!= NULL
783 && s
->session
->ext
.ecpointformats_len
> 0
784 && ((alg_k
& SSL_kECDHE
) || (alg_a
& SSL_aECDSA
))) {
785 /* we are using an ECC cipher */
787 unsigned char *list
= s
->session
->ext
.ecpointformats
;
789 for (i
= 0; i
< s
->session
->ext
.ecpointformats_len
; i
++) {
790 if (*list
++ == TLSEXT_ECPOINTFORMAT_uncompressed
)
793 if (i
== s
->session
->ext
.ecpointformats_len
) {
794 SSLerr(SSL_F_FINAL_EC_PT_FORMATS
,
795 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST
);
804 static int init_session_ticket(SSL
*s
, unsigned int context
)
807 s
->ext
.ticket_expected
= 0;
812 #ifndef OPENSSL_NO_OCSP
813 static int init_status_request(SSL
*s
, unsigned int context
)
816 s
->ext
.status_type
= TLSEXT_STATUSTYPE_nothing
;
819 * Ensure we get sensible values passed to tlsext_status_cb in the event
820 * that we don't receive a status message
822 OPENSSL_free(s
->ext
.ocsp
.resp
);
823 s
->ext
.ocsp
.resp
= NULL
;
824 s
->ext
.ocsp
.resp_len
= 0;
831 #ifndef OPENSSL_NO_NEXTPROTONEG
832 static int init_npn(SSL
*s
, unsigned int context
)
840 static int init_alpn(SSL
*s
, unsigned int context
)
842 OPENSSL_free(s
->s3
->alpn_selected
);
843 s
->s3
->alpn_selected
= NULL
;
845 s
->s3
->alpn_selected_len
= 0;
846 OPENSSL_free(s
->s3
->alpn_proposed
);
847 s
->s3
->alpn_proposed
= NULL
;
848 s
->s3
->alpn_proposed_len
= 0;
853 static int final_alpn(SSL
*s
, unsigned int context
, int sent
, int *al
)
855 const unsigned char *selected
= NULL
;
856 unsigned char selected_len
= 0;
861 if (s
->ctx
->ext
.alpn_select_cb
!= NULL
&& s
->s3
->alpn_proposed
!= NULL
) {
862 int r
= s
->ctx
->ext
.alpn_select_cb(s
, &selected
, &selected_len
,
863 s
->s3
->alpn_proposed
,
864 (unsigned int)s
->s3
->alpn_proposed_len
,
865 s
->ctx
->ext
.alpn_select_cb_arg
);
867 if (r
== SSL_TLSEXT_ERR_OK
) {
868 OPENSSL_free(s
->s3
->alpn_selected
);
869 s
->s3
->alpn_selected
= OPENSSL_memdup(selected
, selected_len
);
870 if (s
->s3
->alpn_selected
== NULL
) {
871 *al
= SSL_AD_INTERNAL_ERROR
;
874 s
->s3
->alpn_selected_len
= selected_len
;
875 #ifndef OPENSSL_NO_NEXTPROTONEG
876 /* ALPN takes precedence over NPN. */
880 *al
= SSL_AD_NO_APPLICATION_PROTOCOL
;
888 static int init_sig_algs(SSL
*s
, unsigned int context
)
890 /* Clear any signature algorithms extension received */
891 OPENSSL_free(s
->s3
->tmp
.peer_sigalgs
);
892 s
->s3
->tmp
.peer_sigalgs
= NULL
;
897 #ifndef OPENSSL_NO_SRP
898 static int init_srp(SSL
*s
, unsigned int context
)
900 OPENSSL_free(s
->srp_ctx
.login
);
901 s
->srp_ctx
.login
= NULL
;
907 static int init_etm(SSL
*s
, unsigned int context
)
909 s
->s3
->flags
&= ~TLS1_FLAGS_ENCRYPT_THEN_MAC
;
914 static int init_ems(SSL
*s
, unsigned int context
)
917 s
->s3
->flags
&= ~TLS1_FLAGS_RECEIVED_EXTMS
;
922 static int final_ems(SSL
*s
, unsigned int context
, int sent
, int *al
)
924 if (!s
->server
&& s
->hit
) {
926 * Check extended master secret extension is consistent with
929 if (!(s
->s3
->flags
& TLS1_FLAGS_RECEIVED_EXTMS
) !=
930 !(s
->session
->flags
& SSL_SESS_FLAG_EXTMS
)) {
931 *al
= SSL_AD_HANDSHAKE_FAILURE
;
932 SSLerr(SSL_F_FINAL_EMS
, SSL_R_INCONSISTENT_EXTMS
);
940 #ifndef OPENSSL_NO_SRTP
941 static int init_srtp(SSL
*s
, unsigned int context
)
944 s
->srtp_profile
= NULL
;
950 static int final_sig_algs(SSL
*s
, unsigned int context
, int sent
, int *al
)
952 if (!sent
&& SSL_IS_TLS13(s
)) {
953 *al
= TLS13_AD_MISSING_EXTENSION
;
954 SSLerr(SSL_F_FINAL_SIG_ALGS
, SSL_R_MISSING_SIGALGS_EXTENSION
);
962 static int final_key_share(SSL
*s
, unsigned int context
, int sent
, int *al
)
964 if (!SSL_IS_TLS13(s
))
969 * we have no key_share
971 * (we are not resuming
972 * OR the kex_mode doesn't allow non key_share resumes)
976 if (((s
->server
&& s
->s3
->peer_tmp
== NULL
) || (!s
->server
&& !sent
))
978 || (s
->ext
.psk_kex_mode
& TLSEXT_KEX_MODE_FLAG_KE
) == 0)) {
979 /* No suitable share */
980 /* TODO(TLS1.3): Send a HelloRetryRequest */
981 *al
= SSL_AD_HANDSHAKE_FAILURE
;
982 SSLerr(SSL_F_FINAL_KEY_SHARE
, SSL_R_NO_SUITABLE_KEY_SHARE
);
987 * For a client side resumption with no key_share we need to generate
988 * the handshake secret (otherwise this is done during key_share
991 if (!sent
&& !s
->server
&& !tls13_generate_handshake_secret(s
, NULL
, 0)) {
992 *al
= SSL_AD_INTERNAL_ERROR
;
993 SSLerr(SSL_F_FINAL_KEY_SHARE
, ERR_R_INTERNAL_ERROR
);
1000 static int init_psk_kex_modes(SSL
*s
, unsigned int context
)
1002 s
->ext
.psk_kex_mode
= TLSEXT_KEX_MODE_FLAG_NONE
;
1006 int tls_psk_do_binder(SSL
*s
, const EVP_MD
*md
, const unsigned char *msgstart
,
1007 size_t binderoffset
, const unsigned char *binderin
,
1008 unsigned char *binderout
,
1009 SSL_SESSION
*sess
, int sign
)
1011 EVP_PKEY
*mackey
= NULL
;
1012 EVP_MD_CTX
*mctx
= NULL
;
1013 unsigned char hash
[EVP_MAX_MD_SIZE
], binderkey
[EVP_MAX_MD_SIZE
];
1014 unsigned char finishedkey
[EVP_MAX_MD_SIZE
], tmpbinder
[EVP_MAX_MD_SIZE
];
1015 const char resumption_label
[] = "resumption psk binder key";
1016 size_t bindersize
, hashsize
= EVP_MD_size(md
);
1019 /* Generate the early_secret */
1020 if (!tls13_generate_secret(s
, md
, NULL
, sess
->master_key
,
1021 sess
->master_key_length
,
1022 (unsigned char *)&s
->early_secret
)) {
1023 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1028 * Create the handshake hash for the binder key...the messages so far are
1031 mctx
= EVP_MD_CTX_new();
1033 || EVP_DigestInit_ex(mctx
, md
, NULL
) <= 0
1034 || EVP_DigestFinal_ex(mctx
, hash
, NULL
) <= 0) {
1035 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1039 /* Generate the binder key */
1040 if (!tls13_hkdf_expand(s
, md
, s
->early_secret
,
1041 (unsigned char *)resumption_label
,
1042 sizeof(resumption_label
) - 1, hash
, binderkey
,
1044 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1048 /* Generate the finished key */
1049 if (!tls13_derive_finishedkey(s
, md
, binderkey
, finishedkey
, hashsize
)) {
1050 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1055 * Get a hash of the ClientHello up to the start of the binders.
1056 * TODO(TLS1.3): This will need to be tweaked when we implement
1057 * HelloRetryRequest to include the digest of the previous messages here.
1059 if (EVP_DigestInit_ex(mctx
, md
, NULL
) <= 0
1060 || EVP_DigestUpdate(mctx
, msgstart
, binderoffset
) <= 0
1061 || EVP_DigestFinal_ex(mctx
, hash
, NULL
) <= 0) {
1062 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1066 mackey
= EVP_PKEY_new_mac_key(EVP_PKEY_HMAC
, NULL
, finishedkey
, hashsize
);
1067 if (mackey
== NULL
) {
1068 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1073 binderout
= tmpbinder
;
1075 bindersize
= hashsize
;
1076 if (EVP_DigestSignInit(mctx
, NULL
, md
, NULL
, mackey
) <= 0
1077 || EVP_DigestSignUpdate(mctx
, hash
, hashsize
) <= 0
1078 || EVP_DigestSignFinal(mctx
, binderout
, &bindersize
) <= 0
1079 || bindersize
!= hashsize
) {
1080 SSLerr(SSL_F_TLS_PSK_DO_BINDER
, ERR_R_INTERNAL_ERROR
);
1087 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */
1088 ret
= (CRYPTO_memcmp(binderin
, binderout
, hashsize
) == 0);
1092 OPENSSL_cleanse(binderkey
, sizeof(binderkey
));
1093 OPENSSL_cleanse(finishedkey
, sizeof(finishedkey
));
1094 EVP_PKEY_free(mackey
);
1095 EVP_MD_CTX_free(mctx
);