2 * Copyright 2014-2016 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 /* Custom extension utility functions */
13 #include <openssl/ct.h>
14 #include "../ssl_locl.h"
15 #include "statem_locl.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 return parse_cb_wrap->parse_cb(s, ext_type, in, inlen, al,
68 parse_cb_wrap->parse_arg);
72 * Find a custom extension from the list. The |server| param is there to
73 * support the legacy API where custom extensions for client and server could
74 * be set independently on the same SSL_CTX. It is set to 1 if we are trying
75 * to find a method relevant to the server, 0 for the client, or -1 if we don't
78 custom_ext_method *custom_ext_find(const custom_ext_methods *exts, int server,
79 unsigned int ext_type, size_t *idx)
82 custom_ext_method *meth = exts->meths;
84 for (i = 0; i < exts->meths_count; i++, meth++) {
85 if (ext_type == meth->ext_type
86 && (server == -1 || server == meth->server
87 || meth->server == -1)) {
97 * Initialise custom extensions flags to indicate neither sent nor received.
99 void custom_ext_init(custom_ext_methods *exts)
102 custom_ext_method *meth = exts->meths;
104 for (i = 0; i < exts->meths_count; i++, meth++)
108 /* Pass received custom extension data to the application for parsing. */
109 int custom_ext_parse(SSL *s, unsigned int context, unsigned int ext_type,
110 const unsigned char *ext_data, size_t ext_size, X509 *x,
111 size_t chainidx, int *al)
113 custom_ext_methods *exts = &s->cert->custext;
114 custom_ext_method *meth;
117 if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
120 meth = custom_ext_find(exts, server, ext_type, NULL);
121 /* If not found return success */
125 /* Check if extension is defined for our protocol. If not, skip */
126 if (!extension_is_relevant(s, meth->context, context))
129 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
130 | SSL_EXT_TLS1_3_SERVER_HELLO
131 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
133 * If it's ServerHello or EncryptedExtensions we can't have any
134 * extensions not sent in ClientHello.
136 if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
137 *al = TLS1_AD_UNSUPPORTED_EXTENSION;
143 * Extensions received in the ClientHello are marked with the
144 * SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
145 * extensions in the ServerHello/EncryptedExtensions message
147 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
148 meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
150 /* If no parse function set return success */
154 return meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
155 al, meth->parse_arg);
159 * Request custom extension data from the application and add to the return
162 int custom_ext_add(SSL *s, int context, WPACKET *pkt, X509 *x, size_t chainidx,
163 int maxversion, int *al)
165 custom_ext_methods *exts = &s->cert->custext;
166 custom_ext_method *meth;
169 for (i = 0; i < exts->meths_count; i++) {
170 const unsigned char *out = NULL;
173 meth = exts->meths + i;
175 if (!should_add_extension(s, meth->context, context, maxversion))
178 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
179 | SSL_EXT_TLS1_3_SERVER_HELLO
180 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
182 * For ServerHello/EncryptedExtensions only send extensions present
185 if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
189 * We skip it if the callback is absent - except for a ClientHello where
190 * we add an empty extension.
192 if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
195 if (meth->add_cb != NULL) {
196 int cb_retval = meth->add_cb(s, meth->ext_type, context, &out,
197 &outlen, x, chainidx, al,
201 return 0; /* error */
203 continue; /* skip this extension */
206 if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
207 || !WPACKET_start_sub_packet_u16(pkt)
208 || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
209 || !WPACKET_close(pkt)) {
210 *al = SSL_AD_INTERNAL_ERROR;
213 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
215 * We can't send duplicates: code logic should prevent this.
217 assert((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0);
219 * Indicate extension has been sent: this is both a sanity check to
220 * ensure we don't send duplicate extensions and indicates that it
221 * is not an error if the extension is present in ServerHello.
223 meth->ext_flags |= SSL_EXT_FLAG_SENT;
225 if (meth->free_cb != NULL)
226 meth->free_cb(s, meth->ext_type, context, out, meth->add_arg);
231 /* Copy table of custom extensions */
232 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
237 if (src->meths_count > 0) {
239 OPENSSL_memdup(src->meths,
240 sizeof(*src->meths) * src->meths_count);
241 if (dst->meths == NULL)
243 dst->meths_count = src->meths_count;
245 for (i = 0; i < src->meths_count; i++) {
246 custom_ext_method *methsrc = src->meths + i;
247 custom_ext_method *methdst = dst->meths + i;
249 if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
253 * We have found an old style API wrapper. We need to copy the
258 methdst->add_arg = NULL;
259 methdst->parse_arg = NULL;
263 methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
264 sizeof(custom_ext_add_cb_wrap));
265 methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
266 sizeof(custom_ext_parse_cb_wrap));
268 if (methdst->add_arg == NULL || methdst->parse_arg == NULL)
274 custom_exts_free(dst);
281 void custom_exts_free(custom_ext_methods *exts)
284 custom_ext_method *meth;
286 for (i = 0, meth = exts->meths; i < exts->meths_count; i++, meth++) {
287 if (meth->add_cb != custom_ext_add_old_cb_wrap)
290 /* Old style API wrapper. Need to free the arguments too */
291 OPENSSL_free(meth->add_arg);
292 OPENSSL_free(meth->parse_arg);
294 OPENSSL_free(exts->meths);
297 /* Return true if a client custom extension exists, false otherwise */
298 int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
300 return custom_ext_find(&ctx->cert->custext, 0, ext_type, NULL) != NULL;
303 static int add_custom_ext_intern(SSL_CTX *ctx, int server,
304 unsigned int ext_type,
305 unsigned int context,
306 custom_ext_add_cb_ex add_cb,
307 custom_ext_free_cb_ex free_cb,
309 custom_ext_parse_cb_ex parse_cb,
312 custom_ext_methods *exts = &ctx->cert->custext;
313 custom_ext_method *meth, *tmp;
316 * Check application error: if add_cb is not set free_cb will never be
319 if (add_cb == NULL && free_cb != NULL)
322 #ifndef OPENSSL_NO_CT
324 * We don't want applications registering callbacks for SCT extensions
325 * whilst simultaneously using the built-in SCT validation features, as
326 * these two things may not play well together.
328 if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
329 && (context & SSL_EXT_CLIENT_HELLO) != 0
330 && SSL_CTX_ct_is_enabled(ctx))
335 * Don't add if extension supported internally, but make exception
336 * for extension types that previously were not supported, but now are.
338 if (SSL_extension_supported(ext_type)
339 && ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
342 /* Extension type must fit in 16 bits */
343 if (ext_type > 0xffff)
345 /* Search for duplicate */
346 if (custom_ext_find(exts, server, ext_type, NULL))
348 tmp = OPENSSL_realloc(exts->meths,
349 (exts->meths_count + 1) * sizeof(custom_ext_method));
354 meth = exts->meths + exts->meths_count;
355 memset(meth, 0, sizeof(*meth));
356 meth->server = server;
357 meth->context = context;
358 meth->parse_cb = parse_cb;
359 meth->add_cb = add_cb;
360 meth->free_cb = free_cb;
361 meth->ext_type = ext_type;
362 meth->add_arg = add_arg;
363 meth->parse_arg = parse_arg;
368 static int add_old_custom_ext(SSL_CTX *ctx, int server, unsigned int ext_type,
369 unsigned int context,
370 custom_ext_add_cb add_cb,
371 custom_ext_free_cb free_cb,
373 custom_ext_parse_cb parse_cb, void *parse_arg)
375 custom_ext_add_cb_wrap *add_cb_wrap
376 = OPENSSL_malloc(sizeof(*add_cb_wrap));
377 custom_ext_parse_cb_wrap *parse_cb_wrap
378 = OPENSSL_malloc(sizeof(*parse_cb_wrap));
381 if (add_cb_wrap == NULL || parse_cb_wrap == NULL) {
382 OPENSSL_free(add_cb_wrap);
383 OPENSSL_free(parse_cb_wrap);
387 add_cb_wrap->add_arg = add_arg;
388 add_cb_wrap->add_cb = add_cb;
389 add_cb_wrap->free_cb = free_cb;
390 parse_cb_wrap->parse_arg = parse_arg;
391 parse_cb_wrap->parse_cb = parse_cb;
394 * TODO(TLS1.3): Is it possible with the old API to add custom exts for both
395 * client and server for the same type in the same SSL_CTX? We don't handle
398 ret = add_custom_ext_intern(ctx, server, ext_type,
400 custom_ext_add_old_cb_wrap,
401 custom_ext_free_old_cb_wrap,
403 custom_ext_parse_old_cb_wrap,
407 OPENSSL_free(add_cb_wrap);
408 OPENSSL_free(parse_cb_wrap);
414 /* Application level functions to add the old custom extension callbacks */
415 int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
416 custom_ext_add_cb add_cb,
417 custom_ext_free_cb free_cb,
419 custom_ext_parse_cb parse_cb, void *parse_arg)
421 return add_old_custom_ext(ctx, 0, ext_type,
422 SSL_EXT_TLS1_2_AND_BELOW_ONLY
423 | SSL_EXT_CLIENT_HELLO
424 | SSL_EXT_TLS1_2_SERVER_HELLO
425 | SSL_EXT_IGNORE_ON_RESUMPTION,
426 add_cb, free_cb, add_arg, parse_cb, parse_arg);
429 int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
430 custom_ext_add_cb add_cb,
431 custom_ext_free_cb free_cb,
433 custom_ext_parse_cb parse_cb, void *parse_arg)
435 return add_old_custom_ext(ctx, 1, ext_type,
436 SSL_EXT_TLS1_2_AND_BELOW_ONLY
437 | SSL_EXT_CLIENT_HELLO
438 | SSL_EXT_TLS1_2_SERVER_HELLO
439 | SSL_EXT_IGNORE_ON_RESUMPTION,
440 add_cb, free_cb, add_arg, parse_cb, parse_arg);
443 int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
444 unsigned int context,
445 custom_ext_add_cb_ex add_cb,
446 custom_ext_free_cb_ex free_cb,
448 custom_ext_parse_cb_ex parse_cb, void *parse_arg)
450 return add_custom_ext_intern(ctx, -1, ext_type, context, add_cb, free_cb,
451 add_arg, parse_cb, parse_arg);
454 int SSL_extension_supported(unsigned int ext_type)
457 /* Internally supported extensions. */
458 case TLSEXT_TYPE_application_layer_protocol_negotiation:
459 #ifndef OPENSSL_NO_EC
460 case TLSEXT_TYPE_ec_point_formats:
461 case TLSEXT_TYPE_supported_groups:
462 case TLSEXT_TYPE_key_share:
464 #ifndef OPENSSL_NO_NEXTPROTONEG
465 case TLSEXT_TYPE_next_proto_neg:
467 case TLSEXT_TYPE_padding:
468 case TLSEXT_TYPE_renegotiate:
469 case TLSEXT_TYPE_server_name:
470 case TLSEXT_TYPE_session_ticket:
471 case TLSEXT_TYPE_signature_algorithms:
472 #ifndef OPENSSL_NO_SRP
473 case TLSEXT_TYPE_srp:
475 #ifndef OPENSSL_NO_OCSP
476 case TLSEXT_TYPE_status_request:
478 #ifndef OPENSSL_NO_CT
479 case TLSEXT_TYPE_signed_certificate_timestamp:
481 #ifndef OPENSSL_NO_SRTP
482 case TLSEXT_TYPE_use_srtp:
484 case TLSEXT_TYPE_encrypt_then_mac:
485 case TLSEXT_TYPE_supported_versions:
486 case TLSEXT_TYPE_extended_master_secret:
487 case TLSEXT_TYPE_psk_kex_modes:
488 case TLSEXT_TYPE_cookie:
489 case TLSEXT_TYPE_early_data:
490 case TLSEXT_TYPE_certificate_authorities:
491 case TLSEXT_TYPE_psk: