2 * Copyright 2014-2020 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 *s, unsigned int context, unsigned int ext_type,
114 const unsigned char *ext_data, size_t ext_size, X509 *x,
118 custom_ext_methods *exts = &s->cert->custext;
119 custom_ext_method *meth;
120 ENDPOINT role = ENDPOINT_BOTH;
122 if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
123 role = s->server ? ENDPOINT_SERVER : ENDPOINT_CLIENT;
125 meth = custom_ext_find(exts, role, ext_type, NULL);
126 /* If not found return success */
130 /* Check if extension is defined for our protocol. If not, skip */
131 if (!extension_is_relevant(s, meth->context, context))
134 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
135 | SSL_EXT_TLS1_3_SERVER_HELLO
136 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
138 * If it's ServerHello or EncryptedExtensions we can't have any
139 * extensions not sent in ClientHello.
141 if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
142 SSLfatal(s, TLS1_AD_UNSUPPORTED_EXTENSION, SSL_R_BAD_EXTENSION);
148 * Extensions received in the ClientHello are marked with the
149 * SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
150 * extensions in the ServerHello/EncryptedExtensions message
152 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
153 meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
155 /* If no parse function set return success */
159 if (meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
160 &al, meth->parse_arg) <= 0) {
161 SSLfatal(s, al, SSL_R_BAD_EXTENSION);
169 * Request custom extension data from the application and add to the return
172 int custom_ext_add(SSL *s, int context, WPACKET *pkt, X509 *x, size_t chainidx,
175 custom_ext_methods *exts = &s->cert->custext;
176 custom_ext_method *meth;
180 for (i = 0; i < exts->meths_count; i++) {
181 const unsigned char *out = NULL;
184 meth = exts->meths + i;
186 if (!should_add_extension(s, meth->context, context, maxversion))
189 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
190 | SSL_EXT_TLS1_3_SERVER_HELLO
191 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
192 | SSL_EXT_TLS1_3_CERTIFICATE
193 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST)) != 0) {
194 /* Only send extensions present in ClientHello. */
195 if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
199 * We skip it if the callback is absent - except for a ClientHello where
200 * we add an empty extension.
202 if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
205 if (meth->add_cb != NULL) {
206 int cb_retval = meth->add_cb(s, meth->ext_type, context, &out,
207 &outlen, x, chainidx, &al,
211 SSLfatal(s, al, SSL_R_CALLBACK_FAILED);
212 return 0; /* error */
215 continue; /* skip this extension */
218 if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
219 || !WPACKET_start_sub_packet_u16(pkt)
220 || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
221 || !WPACKET_close(pkt)) {
222 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
225 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
227 * We can't send duplicates: code logic should prevent this.
229 if (!ossl_assert((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0)) {
230 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
234 * Indicate extension has been sent: this is both a sanity check to
235 * ensure we don't send duplicate extensions and indicates that it
236 * is not an error if the extension is present in ServerHello.
238 meth->ext_flags |= SSL_EXT_FLAG_SENT;
240 if (meth->free_cb != NULL)
241 meth->free_cb(s, meth->ext_type, context, out, meth->add_arg);
246 /* Copy the flags from src to dst for any extensions that exist in both */
247 int custom_exts_copy_flags(custom_ext_methods *dst,
248 const custom_ext_methods *src)
251 custom_ext_method *methsrc = src->meths;
253 for (i = 0; i < src->meths_count; i++, methsrc++) {
254 custom_ext_method *methdst = custom_ext_find(dst, methsrc->role,
255 methsrc->ext_type, NULL);
260 methdst->ext_flags = methsrc->ext_flags;
266 /* Copy table of custom extensions */
267 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
272 if (src->meths_count > 0) {
274 OPENSSL_memdup(src->meths,
275 sizeof(*src->meths) * src->meths_count);
276 if (dst->meths == NULL)
278 dst->meths_count = src->meths_count;
280 for (i = 0; i < src->meths_count; i++) {
281 custom_ext_method *methsrc = src->meths + i;
282 custom_ext_method *methdst = dst->meths + i;
284 if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
288 * We have found an old style API wrapper. We need to copy the
293 methdst->add_arg = NULL;
294 methdst->parse_arg = NULL;
298 methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
299 sizeof(custom_ext_add_cb_wrap));
300 methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
301 sizeof(custom_ext_parse_cb_wrap));
303 if (methdst->add_arg == NULL || methdst->parse_arg == NULL)
309 custom_exts_free(dst);
316 void custom_exts_free(custom_ext_methods *exts)
319 custom_ext_method *meth;
321 for (i = 0, meth = exts->meths; i < exts->meths_count; i++, meth++) {
322 if (meth->add_cb != custom_ext_add_old_cb_wrap)
325 /* Old style API wrapper. Need to free the arguments too */
326 OPENSSL_free(meth->add_arg);
327 OPENSSL_free(meth->parse_arg);
329 OPENSSL_free(exts->meths);
332 /* Return true if a client custom extension exists, false otherwise */
333 int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
335 return custom_ext_find(&ctx->cert->custext, ENDPOINT_CLIENT, ext_type,
339 static int add_custom_ext_intern(SSL_CTX *ctx, ENDPOINT role,
340 unsigned int ext_type,
341 unsigned int context,
342 SSL_custom_ext_add_cb_ex add_cb,
343 SSL_custom_ext_free_cb_ex free_cb,
345 SSL_custom_ext_parse_cb_ex parse_cb,
348 custom_ext_methods *exts = &ctx->cert->custext;
349 custom_ext_method *meth, *tmp;
352 * Check application error: if add_cb is not set free_cb will never be
355 if (add_cb == NULL && free_cb != NULL)
358 #ifndef OPENSSL_NO_CT
360 * We don't want applications registering callbacks for SCT extensions
361 * whilst simultaneously using the built-in SCT validation features, as
362 * these two things may not play well together.
364 if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
365 && (context & SSL_EXT_CLIENT_HELLO) != 0
366 && SSL_CTX_ct_is_enabled(ctx))
371 * Don't add if extension supported internally, but make exception
372 * for extension types that previously were not supported, but now are.
374 if (SSL_extension_supported(ext_type)
375 && ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
378 /* Extension type must fit in 16 bits */
379 if (ext_type > 0xffff)
381 /* Search for duplicate */
382 if (custom_ext_find(exts, role, ext_type, NULL))
384 tmp = OPENSSL_realloc(exts->meths,
385 (exts->meths_count + 1) * sizeof(custom_ext_method));
390 meth = exts->meths + exts->meths_count;
391 memset(meth, 0, sizeof(*meth));
393 meth->context = context;
394 meth->parse_cb = parse_cb;
395 meth->add_cb = add_cb;
396 meth->free_cb = free_cb;
397 meth->ext_type = ext_type;
398 meth->add_arg = add_arg;
399 meth->parse_arg = parse_arg;
404 static int add_old_custom_ext(SSL_CTX *ctx, ENDPOINT role,
405 unsigned int ext_type,
406 unsigned int context,
407 custom_ext_add_cb add_cb,
408 custom_ext_free_cb free_cb,
410 custom_ext_parse_cb parse_cb, void *parse_arg)
412 custom_ext_add_cb_wrap *add_cb_wrap
413 = OPENSSL_malloc(sizeof(*add_cb_wrap));
414 custom_ext_parse_cb_wrap *parse_cb_wrap
415 = OPENSSL_malloc(sizeof(*parse_cb_wrap));
418 if (add_cb_wrap == NULL || parse_cb_wrap == NULL) {
419 OPENSSL_free(add_cb_wrap);
420 OPENSSL_free(parse_cb_wrap);
424 add_cb_wrap->add_arg = add_arg;
425 add_cb_wrap->add_cb = add_cb;
426 add_cb_wrap->free_cb = free_cb;
427 parse_cb_wrap->parse_arg = parse_arg;
428 parse_cb_wrap->parse_cb = parse_cb;
430 ret = add_custom_ext_intern(ctx, role, ext_type,
432 custom_ext_add_old_cb_wrap,
433 custom_ext_free_old_cb_wrap,
435 custom_ext_parse_old_cb_wrap,
439 OPENSSL_free(add_cb_wrap);
440 OPENSSL_free(parse_cb_wrap);
446 /* Application level functions to add the old custom extension callbacks */
447 int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
448 custom_ext_add_cb add_cb,
449 custom_ext_free_cb free_cb,
451 custom_ext_parse_cb parse_cb, void *parse_arg)
453 return add_old_custom_ext(ctx, ENDPOINT_CLIENT, ext_type,
454 SSL_EXT_TLS1_2_AND_BELOW_ONLY
455 | SSL_EXT_CLIENT_HELLO
456 | SSL_EXT_TLS1_2_SERVER_HELLO
457 | SSL_EXT_IGNORE_ON_RESUMPTION,
458 add_cb, free_cb, add_arg, parse_cb, parse_arg);
461 int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
462 custom_ext_add_cb add_cb,
463 custom_ext_free_cb free_cb,
465 custom_ext_parse_cb parse_cb, void *parse_arg)
467 return add_old_custom_ext(ctx, ENDPOINT_SERVER, ext_type,
468 SSL_EXT_TLS1_2_AND_BELOW_ONLY
469 | SSL_EXT_CLIENT_HELLO
470 | SSL_EXT_TLS1_2_SERVER_HELLO
471 | SSL_EXT_IGNORE_ON_RESUMPTION,
472 add_cb, free_cb, add_arg, parse_cb, parse_arg);
475 int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
476 unsigned int context,
477 SSL_custom_ext_add_cb_ex add_cb,
478 SSL_custom_ext_free_cb_ex free_cb,
480 SSL_custom_ext_parse_cb_ex parse_cb, void *parse_arg)
482 return add_custom_ext_intern(ctx, ENDPOINT_BOTH, ext_type, context, add_cb,
483 free_cb, add_arg, parse_cb, parse_arg);
486 int SSL_extension_supported(unsigned int ext_type)
489 /* Internally supported extensions. */
490 case TLSEXT_TYPE_application_layer_protocol_negotiation:
491 case TLSEXT_TYPE_ec_point_formats:
492 case TLSEXT_TYPE_supported_groups:
493 case TLSEXT_TYPE_key_share:
494 #ifndef OPENSSL_NO_NEXTPROTONEG
495 case TLSEXT_TYPE_next_proto_neg:
497 case TLSEXT_TYPE_padding:
498 case TLSEXT_TYPE_renegotiate:
499 case TLSEXT_TYPE_max_fragment_length:
500 case TLSEXT_TYPE_server_name:
501 case TLSEXT_TYPE_session_ticket:
502 case TLSEXT_TYPE_signature_algorithms:
503 #ifndef OPENSSL_NO_SRP
504 case TLSEXT_TYPE_srp:
506 #ifndef OPENSSL_NO_OCSP
507 case TLSEXT_TYPE_status_request:
509 #ifndef OPENSSL_NO_CT
510 case TLSEXT_TYPE_signed_certificate_timestamp:
512 #ifndef OPENSSL_NO_SRTP
513 case TLSEXT_TYPE_use_srtp:
515 case TLSEXT_TYPE_encrypt_then_mac:
516 case TLSEXT_TYPE_supported_versions:
517 case TLSEXT_TYPE_extended_master_secret:
518 case TLSEXT_TYPE_psk_kex_modes:
519 case TLSEXT_TYPE_cookie:
520 case TLSEXT_TYPE_early_data:
521 case TLSEXT_TYPE_certificate_authorities:
522 case TLSEXT_TYPE_psk:
523 case TLSEXT_TYPE_post_handshake_auth: