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)
83 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;
103 for (i = 0; i < exts->meths_count; i++, meth++)
107 /* Pass received custom extension data to the application for parsing. */
108 int custom_ext_parse(SSL *s, unsigned int context, unsigned int ext_type,
109 const unsigned char *ext_data, size_t ext_size, X509 *x,
110 size_t chainidx, int *al)
112 custom_ext_methods *exts = &s->cert->custext;
113 custom_ext_method *meth;
116 if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
119 meth = custom_ext_find(exts, server, ext_type, NULL);
120 /* If not found return success */
124 /* Check if extension is defined for our protocol. If not, skip */
125 if (!extension_is_relevant(s, meth->context, context))
128 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
129 | SSL_EXT_TLS1_3_SERVER_HELLO
130 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
132 * If it's ServerHello or EncryptedExtensions we can't have any
133 * extensions not sent in ClientHello.
135 if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
136 *al = TLS1_AD_UNSUPPORTED_EXTENSION;
142 * Extensions received in the ClientHello are marked with the
143 * SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
144 * extensions in the ServerHello/EncryptedExtensions message
146 if ((context & SSL_EXT_CLIENT_HELLO) != 0)
147 meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
149 /* If no parse function set return success */
153 return meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
154 al, meth->parse_arg);
158 * Request custom extension data from the application and add to the return
161 int custom_ext_add(SSL *s, int context, WPACKET *pkt, X509 *x, size_t chainidx,
162 int maxversion, int *al)
164 custom_ext_methods *exts = &s->cert->custext;
165 custom_ext_method *meth;
168 for (i = 0; i < exts->meths_count; i++) {
169 const unsigned char *out = NULL;
172 meth = exts->meths + i;
174 if (!should_add_extension(s, meth->context, context, maxversion))
177 if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
178 | SSL_EXT_TLS1_3_SERVER_HELLO
179 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
181 * For ServerHello/EncryptedExtensions only send extensions present
184 if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
188 * We skip it if the callback is absent - except for a ClientHello where
189 * we add an empty extension.
191 if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
194 if (meth->add_cb != NULL) {
196 cb_retval = meth->add_cb(s, meth->ext_type, context, &out, &outlen,
197 x, chainidx, al, meth->add_arg);
199 return 0; /* error */
201 continue; /* skip this extension */
204 if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
205 || !WPACKET_start_sub_packet_u16(pkt)
206 || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
207 || !WPACKET_close(pkt)) {
208 *al = SSL_AD_INTERNAL_ERROR;
211 if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
213 * We can't send duplicates: code logic should prevent this.
215 assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
217 * Indicate extension has been sent: this is both a sanity check to
218 * ensure we don't send duplicate extensions and indicates that it
219 * is not an error if the extension is present in ServerHello.
221 meth->ext_flags |= SSL_EXT_FLAG_SENT;
224 meth->free_cb(s, meth->ext_type, context, out, meth->add_arg);
229 /* Copy table of custom extensions */
230 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
235 if (src->meths_count > 0) {
237 OPENSSL_memdup(src->meths,
238 sizeof(custom_ext_method) * src->meths_count);
239 if (dst->meths == NULL)
241 dst->meths_count = src->meths_count;
243 for (i = 0; i < src->meths_count; i++) {
244 custom_ext_method *methsrc = src->meths + i;
245 custom_ext_method *methdst = dst->meths + i;
247 if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
251 * We have found an old style API wrapper. We need to copy the
256 methdst->add_arg = NULL;
257 methdst->parse_arg = NULL;
261 methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
262 sizeof(custom_ext_add_cb_wrap));
263 methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
264 sizeof(custom_ext_parse_cb_wrap));
266 if (methdst->add_arg == NULL || methdst->parse_arg == NULL)
272 custom_exts_free(dst);
279 void custom_exts_free(custom_ext_methods *exts)
283 for (i = 0; i < exts->meths_count; i++) {
284 custom_ext_method *meth = exts->meths + i;
286 if (meth->add_cb != custom_ext_add_old_cb_wrap)
289 /* Old style API wrapper. Need to free the arguments too */
290 OPENSSL_free(meth->add_arg);
291 OPENSSL_free(meth->parse_arg);
293 OPENSSL_free(exts->meths);
296 /* Return true if a client custom extension exists, false otherwise */
297 int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
299 return custom_ext_find(&ctx->cert->custext, 0, ext_type, NULL) != NULL;
302 static int add_custom_ext_intern(SSL_CTX *ctx, int server,
303 unsigned int ext_type,
304 unsigned int context,
305 custom_ext_add_cb_ex add_cb,
306 custom_ext_free_cb_ex free_cb,
308 custom_ext_parse_cb_ex parse_cb,
311 custom_ext_methods *exts = &ctx->cert->custext;
312 custom_ext_method *meth, *tmp;
315 * Check application error: if add_cb is not set free_cb will never be
318 if (!add_cb && free_cb)
321 #ifndef OPENSSL_NO_CT
323 * We don't want applications registering callbacks for SCT extensions
324 * whilst simultaneously using the built-in SCT validation features, as
325 * these two things may not play well together.
327 if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
328 && (context & SSL_EXT_CLIENT_HELLO) != 0
329 && SSL_CTX_ct_is_enabled(ctx))
334 * Don't add if extension supported internally, but make exception
335 * for extension types that previously were not supported, but now are.
337 if (SSL_extension_supported(ext_type)
338 && ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
341 /* Extension type must fit in 16 bits */
342 if (ext_type > 0xffff)
344 /* Search for duplicate */
345 if (custom_ext_find(exts, server, ext_type, NULL))
347 tmp = OPENSSL_realloc(exts->meths,
348 (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(custom_ext_add_cb_wrap));
377 custom_ext_parse_cb_wrap *parse_cb_wrap
378 = OPENSSL_malloc(sizeof(custom_ext_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: