2 * Copyright 2014-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (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 /* Custom extension utility functions */
12 #include <openssl/ct.h>
13 #include "../ssl_local.h"
14 #include "internal/cryptlib.h"
15 #include "statem_local.h"
19 custom_ext_add_cb add_cb;
20 custom_ext_free_cb free_cb;
21 } custom_ext_add_cb_wrap;
25 custom_ext_parse_cb parse_cb;
26 } custom_ext_parse_cb_wrap;
29 * Provide thin wrapper callbacks which convert new style arguments to old style
31 static int custom_ext_add_old_cb_wrap(SSL *s, unsigned int ext_type,
33 const unsigned char **out,
34 size_t *outlen, X509 *x, size_t chainidx,
35 int *al, void *add_arg)
37 custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;
39 if (add_cb_wrap->add_cb == NULL)
42 return add_cb_wrap->add_cb(s, ext_type, out, outlen, al,
43 add_cb_wrap->add_arg);
46 static void custom_ext_free_old_cb_wrap(SSL *s, unsigned int ext_type,
48 const unsigned char *out, void *add_arg)
50 custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;
52 if (add_cb_wrap->free_cb == NULL)
55 add_cb_wrap->free_cb(s, ext_type, out, add_cb_wrap->add_arg);
58 static int custom_ext_parse_old_cb_wrap(SSL *s, unsigned int ext_type,
60 const unsigned char *in,
61 size_t inlen, X509 *x, size_t chainidx,
62 int *al, void *parse_arg)
64 custom_ext_parse_cb_wrap *parse_cb_wrap =
65 (custom_ext_parse_cb_wrap *)parse_arg;
67 if (parse_cb_wrap->parse_cb == NULL)
70 return parse_cb_wrap->parse_cb(s, ext_type, in, inlen, al,
71 parse_cb_wrap->parse_arg);
75 * Find a custom extension from the list. The |role| param is there to
76 * support the legacy API where custom extensions for client and server could
77 * be set independently on the same SSL_CTX. It is set to ENDPOINT_SERVER if we
78 * are trying to find a method relevant to the server, ENDPOINT_CLIENT for the
79 * client, or ENDPOINT_BOTH for either
81 custom_ext_method *custom_ext_find(const custom_ext_methods *exts,
82 ENDPOINT role, unsigned int ext_type,
86 custom_ext_method *meth = exts->meths;
88 for (i = 0; i < exts->meths_count; i++, meth++) {
89 if (ext_type == meth->ext_type
90 && (role == ENDPOINT_BOTH || role == meth->role
91 || meth->role == ENDPOINT_BOTH)) {
101 * Initialise custom extensions flags to indicate neither sent nor received.
103 void custom_ext_init(custom_ext_methods *exts)
106 custom_ext_method *meth = exts->meths;
108 for (i = 0; i < exts->meths_count; i++, meth++)
112 /* Pass received custom extension data to the application for parsing. */
113 int custom_ext_parse(SSL_CONNECTION *s, unsigned int context,
114 unsigned int ext_type,
115 const unsigned char *ext_data, size_t ext_size, X509 *x,
119 custom_ext_methods *exts = &s->cert->custext;
120 custom_ext_method *meth;
121 ENDPOINT role = ENDPOINT_BOTH;
123 if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
124 role = s->server ? ENDPOINT_SERVER : ENDPOINT_CLIENT;
126 meth = custom_ext_find(exts, role, ext_type, NULL);
127 /* If not found return success */
131 /* Check if extension is defined for our protocol. If not, skip */
132 if (!extension_is_relevant(s, meth->context, context))
135 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
136 | SSL_EXT_TLS1_3_SERVER_HELLO
137 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
139 * If it's ServerHello or EncryptedExtensions we can't have any
140 * extensions not sent in ClientHello.
142 if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
143 SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
149 * Extensions received in the ClientHello or CertificateRequest are marked
150 * with the SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
151 * extensions in the response messages
153 if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST))
155 meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
157 /* If no parse function set return success */
158 if (meth->parse_cb == NULL)
161 if (meth->parse_cb(SSL_CONNECTION_GET_SSL(s), ext_type, context, ext_data,
162 ext_size, x, chainidx, &al, meth->parse_arg) <= 0) {
163 SSLfatal(s, al, SSL_R_BAD_EXTENSION);
171 * Request custom extension data from the application and add to the return
174 int custom_ext_add(SSL_CONNECTION *s, int context, WPACKET *pkt, X509 *x,
175 size_t chainidx, int maxversion)
177 custom_ext_methods *exts = &s->cert->custext;
178 custom_ext_method *meth;
182 for (i = 0; i < exts->meths_count; i++) {
183 const unsigned char *out = NULL;
186 meth = exts->meths + i;
188 if (!should_add_extension(s, meth->context, context, maxversion))
191 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
192 | SSL_EXT_TLS1_3_SERVER_HELLO
193 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
194 | SSL_EXT_TLS1_3_CERTIFICATE
195 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)) != 0) {
196 /* Only send extensions present in ClientHello/CertificateRequest */
197 if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
201 * We skip it if the callback is absent - except for a ClientHello where
202 * we add an empty extension.
204 if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
207 if (meth->add_cb != NULL) {
208 int cb_retval = meth->add_cb(SSL_CONNECTION_GET_SSL(s),
209 meth->ext_type, context, &out,
210 &outlen, x, chainidx, &al,
214 SSLfatal(s, al, SSL_R_CALLBACK_FAILED);
215 return 0; /* error */
218 continue; /* skip this extension */
221 if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
222 || !WPACKET_start_sub_packet_u16(pkt)
223 || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
224 || !WPACKET_close(pkt)) {
225 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
228 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
230 * We can't send duplicates: code logic should prevent this.
232 if (!ossl_assert((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0)) {
233 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
237 * Indicate extension has been sent: this is both a sanity check to
238 * ensure we don't send duplicate extensions and indicates that it
239 * is not an error if the extension is present in ServerHello.
241 meth->ext_flags |= SSL_EXT_FLAG_SENT;
243 if (meth->free_cb != NULL)
244 meth->free_cb(SSL_CONNECTION_GET_SSL(s), meth->ext_type, context,
250 /* Copy the flags from src to dst for any extensions that exist in both */
251 int custom_exts_copy_flags(custom_ext_methods *dst,
252 const custom_ext_methods *src)
255 custom_ext_method *methsrc = src->meths;
257 for (i = 0; i < src->meths_count; i++, methsrc++) {
258 custom_ext_method *methdst = custom_ext_find(dst, methsrc->role,
259 methsrc->ext_type, NULL);
264 methdst->ext_flags = methsrc->ext_flags;
270 /* Copy table of custom extensions */
271 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
276 if (src->meths_count > 0) {
278 OPENSSL_memdup(src->meths,
279 sizeof(*src->meths) * src->meths_count);
280 if (dst->meths == NULL)
282 dst->meths_count = src->meths_count;
284 for (i = 0; i < src->meths_count; i++) {
285 custom_ext_method *methsrc = src->meths + i;
286 custom_ext_method *methdst = dst->meths + i;
288 if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
292 * We have found an old style API wrapper. We need to copy the
297 methdst->add_arg = NULL;
298 methdst->parse_arg = NULL;
302 methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
303 sizeof(custom_ext_add_cb_wrap));
304 methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
305 sizeof(custom_ext_parse_cb_wrap));
307 if (methdst->add_arg == NULL || methdst->parse_arg == NULL)
313 custom_exts_free(dst);
320 void custom_exts_free(custom_ext_methods *exts)
323 custom_ext_method *meth;
325 for (i = 0, meth = exts->meths; i < exts->meths_count; i++, meth++) {
326 if (meth->add_cb != custom_ext_add_old_cb_wrap)
329 /* Old style API wrapper. Need to free the arguments too */
330 OPENSSL_free(meth->add_arg);
331 OPENSSL_free(meth->parse_arg);
333 OPENSSL_free(exts->meths);
336 /* Return true if a client custom extension exists, false otherwise */
337 int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
339 return custom_ext_find(&ctx->cert->custext, ENDPOINT_CLIENT, ext_type,
343 static int add_custom_ext_intern(SSL_CTX *ctx, ENDPOINT role,
344 unsigned int ext_type,
345 unsigned int context,
346 SSL_custom_ext_add_cb_ex add_cb,
347 SSL_custom_ext_free_cb_ex free_cb,
349 SSL_custom_ext_parse_cb_ex parse_cb,
352 custom_ext_methods *exts = &ctx->cert->custext;
353 custom_ext_method *meth, *tmp;
356 * Check application error: if add_cb is not set free_cb will never be
359 if (add_cb == NULL && free_cb != NULL)
362 #ifndef OPENSSL_NO_CT
364 * We don't want applications registering callbacks for SCT extensions
365 * whilst simultaneously using the built-in SCT validation features, as
366 * these two things may not play well together.
368 if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
369 && (context & SSL_EXT_CLIENT_HELLO) != 0
370 && SSL_CTX_ct_is_enabled(ctx))
375 * Don't add if extension supported internally, but make exception
376 * for extension types that previously were not supported, but now are.
378 if (SSL_extension_supported(ext_type)
379 && ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
382 /* Extension type must fit in 16 bits */
383 if (ext_type > 0xffff)
385 /* Search for duplicate */
386 if (custom_ext_find(exts, role, ext_type, NULL))
388 tmp = OPENSSL_realloc(exts->meths,
389 (exts->meths_count + 1) * sizeof(custom_ext_method));
394 meth = exts->meths + exts->meths_count;
395 memset(meth, 0, sizeof(*meth));
397 meth->context = context;
398 meth->parse_cb = parse_cb;
399 meth->add_cb = add_cb;
400 meth->free_cb = free_cb;
401 meth->ext_type = ext_type;
402 meth->add_arg = add_arg;
403 meth->parse_arg = parse_arg;
408 static int add_old_custom_ext(SSL_CTX *ctx, ENDPOINT role,
409 unsigned int ext_type,
410 unsigned int context,
411 custom_ext_add_cb add_cb,
412 custom_ext_free_cb free_cb,
414 custom_ext_parse_cb parse_cb, void *parse_arg)
416 custom_ext_add_cb_wrap *add_cb_wrap
417 = OPENSSL_malloc(sizeof(*add_cb_wrap));
418 custom_ext_parse_cb_wrap *parse_cb_wrap
419 = OPENSSL_malloc(sizeof(*parse_cb_wrap));
422 if (add_cb_wrap == NULL || parse_cb_wrap == NULL) {
423 OPENSSL_free(add_cb_wrap);
424 OPENSSL_free(parse_cb_wrap);
428 add_cb_wrap->add_arg = add_arg;
429 add_cb_wrap->add_cb = add_cb;
430 add_cb_wrap->free_cb = free_cb;
431 parse_cb_wrap->parse_arg = parse_arg;
432 parse_cb_wrap->parse_cb = parse_cb;
434 ret = add_custom_ext_intern(ctx, role, ext_type,
436 custom_ext_add_old_cb_wrap,
437 custom_ext_free_old_cb_wrap,
439 custom_ext_parse_old_cb_wrap,
443 OPENSSL_free(add_cb_wrap);
444 OPENSSL_free(parse_cb_wrap);
450 /* Application level functions to add the old custom extension callbacks */
451 int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
452 custom_ext_add_cb add_cb,
453 custom_ext_free_cb free_cb,
455 custom_ext_parse_cb parse_cb, void *parse_arg)
457 return add_old_custom_ext(ctx, ENDPOINT_CLIENT, ext_type,
458 SSL_EXT_TLS1_2_AND_BELOW_ONLY
459 | SSL_EXT_CLIENT_HELLO
460 | SSL_EXT_TLS1_2_SERVER_HELLO
461 | SSL_EXT_IGNORE_ON_RESUMPTION,
462 add_cb, free_cb, add_arg, parse_cb, parse_arg);
465 int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
466 custom_ext_add_cb add_cb,
467 custom_ext_free_cb free_cb,
469 custom_ext_parse_cb parse_cb, void *parse_arg)
471 return add_old_custom_ext(ctx, ENDPOINT_SERVER, ext_type,
472 SSL_EXT_TLS1_2_AND_BELOW_ONLY
473 | SSL_EXT_CLIENT_HELLO
474 | SSL_EXT_TLS1_2_SERVER_HELLO
475 | SSL_EXT_IGNORE_ON_RESUMPTION,
476 add_cb, free_cb, add_arg, parse_cb, parse_arg);
479 int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
480 unsigned int context,
481 SSL_custom_ext_add_cb_ex add_cb,
482 SSL_custom_ext_free_cb_ex free_cb,
484 SSL_custom_ext_parse_cb_ex parse_cb, void *parse_arg)
486 return add_custom_ext_intern(ctx, ENDPOINT_BOTH, ext_type, context, add_cb,
487 free_cb, add_arg, parse_cb, parse_arg);
490 int SSL_extension_supported(unsigned int ext_type)
493 /* Internally supported extensions. */
494 case TLSEXT_TYPE_application_layer_protocol_negotiation:
495 case TLSEXT_TYPE_ec_point_formats:
496 case TLSEXT_TYPE_supported_groups:
497 case TLSEXT_TYPE_key_share:
498 #ifndef OPENSSL_NO_NEXTPROTONEG
499 case TLSEXT_TYPE_next_proto_neg:
501 case TLSEXT_TYPE_padding:
502 case TLSEXT_TYPE_renegotiate:
503 case TLSEXT_TYPE_max_fragment_length:
504 case TLSEXT_TYPE_server_name:
505 case TLSEXT_TYPE_session_ticket:
506 case TLSEXT_TYPE_signature_algorithms:
507 #ifndef OPENSSL_NO_SRP
508 case TLSEXT_TYPE_srp:
510 #ifndef OPENSSL_NO_OCSP
511 case TLSEXT_TYPE_status_request:
513 #ifndef OPENSSL_NO_CT
514 case TLSEXT_TYPE_signed_certificate_timestamp:
516 #ifndef OPENSSL_NO_SRTP
517 case TLSEXT_TYPE_use_srtp:
519 case TLSEXT_TYPE_encrypt_then_mac:
520 case TLSEXT_TYPE_supported_versions:
521 case TLSEXT_TYPE_extended_master_secret:
522 case TLSEXT_TYPE_psk_kex_modes:
523 case TLSEXT_TYPE_cookie:
524 case TLSEXT_TYPE_early_data:
525 case TLSEXT_TYPE_certificate_authorities:
526 case TLSEXT_TYPE_psk:
527 case TLSEXT_TYPE_post_handshake_auth: