1 /*
2 * SSLv3/TLSv1 server-side functions
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 *
7 * This file is provided under the Apache License 2.0, or the
8 * GNU General Public License v2.0 or later.
9 *
10 * **********
11 * Apache License 2.0:
12 *
13 * Licensed under the Apache License, Version 2.0 (the "License"); you may
14 * not use this file except in compliance with the License.
15 * You may obtain a copy of the License at
16 *
17 * http://www.apache.org/licenses/LICENSE-2.0
18 *
19 * Unless required by applicable law or agreed to in writing, software
20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22 * See the License for the specific language governing permissions and
23 * limitations under the License.
24 *
25 * **********
26 *
27 * **********
28 * GNU General Public License v2.0 or later:
29 *
30 * This program is free software; you can redistribute it and/or modify
31 * it under the terms of the GNU General Public License as published by
32 * the Free Software Foundation; either version 2 of the License, or
33 * (at your option) any later version.
34 *
35 * This program is distributed in the hope that it will be useful,
36 * but WITHOUT ANY WARRANTY; without even the implied warranty of
37 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
38 * GNU General Public License for more details.
39 *
40 * You should have received a copy of the GNU General Public License along
41 * with this program; if not, write to the Free Software Foundation, Inc.,
42 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
43 *
44 * **********
45 */
46
47 #if !defined(MBEDTLS_CONFIG_FILE)
48 #include "mbedtls/config.h"
49 #else
50 #include MBEDTLS_CONFIG_FILE
51 #endif
52
53 #if defined(MBEDTLS_SSL_SRV_C)
54
55 #if defined(MBEDTLS_PLATFORM_C)
56 #include "mbedtls/platform.h"
57 #else
58 #include <stdlib.h>
59 #define mbedtls_calloc calloc
60 #define mbedtls_free free
61 #endif
62
63 #include "mbedtls/debug.h"
64 #include "mbedtls/ssl.h"
65 #include "mbedtls/ssl_internal.h"
66 #include "mbedtls/platform_util.h"
67
68 #include <string.h>
69
70 #if defined(MBEDTLS_ECP_C)
71 #include "mbedtls/ecp.h"
72 #endif
73
74 #if defined(MBEDTLS_HAVE_TIME)
75 #include "mbedtls/platform_time.h"
76 #endif
77
78 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context * ssl,const unsigned char * info,size_t ilen)79 int mbedtls_ssl_set_client_transport_id( mbedtls_ssl_context *ssl,
80 const unsigned char *info,
81 size_t ilen )
82 {
83 if( ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER )
84 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
85
86 mbedtls_free( ssl->cli_id );
87
88 if( ( ssl->cli_id = mbedtls_calloc( 1, ilen ) ) == NULL )
89 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
90
91 memcpy( ssl->cli_id, info, ilen );
92 ssl->cli_id_len = ilen;
93
94 return( 0 );
95 }
96
mbedtls_ssl_conf_dtls_cookies(mbedtls_ssl_config * conf,mbedtls_ssl_cookie_write_t * f_cookie_write,mbedtls_ssl_cookie_check_t * f_cookie_check,void * p_cookie)97 void mbedtls_ssl_conf_dtls_cookies( mbedtls_ssl_config *conf,
98 mbedtls_ssl_cookie_write_t *f_cookie_write,
99 mbedtls_ssl_cookie_check_t *f_cookie_check,
100 void *p_cookie )
101 {
102 conf->f_cookie_write = f_cookie_write;
103 conf->f_cookie_check = f_cookie_check;
104 conf->p_cookie = p_cookie;
105 }
106 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
107
108 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
ssl_parse_servername_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)109 static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
110 const unsigned char *buf,
111 size_t len )
112 {
113 int ret;
114 size_t servername_list_size, hostname_len;
115 const unsigned char *p;
116
117 MBEDTLS_SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) );
118
119 if( len < 2 )
120 {
121 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
122 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
123 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
124 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
125 }
126 servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
127 if( servername_list_size + 2 != len )
128 {
129 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
130 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
131 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
132 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
133 }
134
135 p = buf + 2;
136 while( servername_list_size > 2 )
137 {
138 hostname_len = ( ( p[1] << 8 ) | p[2] );
139 if( hostname_len + 3 > servername_list_size )
140 {
141 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
142 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
143 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
144 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
145 }
146
147 if( p[0] == MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME )
148 {
149 ret = ssl->conf->f_sni( ssl->conf->p_sni,
150 ssl, p + 3, hostname_len );
151 if( ret != 0 )
152 {
153 MBEDTLS_SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret );
154 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
155 MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME );
156 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
157 }
158 return( 0 );
159 }
160
161 servername_list_size -= hostname_len + 3;
162 p += hostname_len + 3;
163 }
164
165 if( servername_list_size != 0 )
166 {
167 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
168 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
169 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
170 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
171 }
172
173 return( 0 );
174 }
175 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
176
ssl_parse_renegotiation_info(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)177 static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
178 const unsigned char *buf,
179 size_t len )
180 {
181 #if defined(MBEDTLS_SSL_RENEGOTIATION)
182 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
183 {
184 /* Check verify-data in constant-time. The length OTOH is no secret */
185 if( len != 1 + ssl->verify_data_len ||
186 buf[0] != ssl->verify_data_len ||
187 mbedtls_ssl_safer_memcmp( buf + 1, ssl->peer_verify_data,
188 ssl->verify_data_len ) != 0 )
189 {
190 MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
191 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
192 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
193 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
194 }
195 }
196 else
197 #endif /* MBEDTLS_SSL_RENEGOTIATION */
198 {
199 if( len != 1 || buf[0] != 0x0 )
200 {
201 MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
202 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
203 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
204 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
205 }
206
207 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
208 }
209
210 return( 0 );
211 }
212
213 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
214 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
215
216 /*
217 * Status of the implementation of signature-algorithms extension:
218 *
219 * Currently, we are only considering the signature-algorithm extension
220 * to pick a ciphersuite which allows us to send the ServerKeyExchange
221 * message with a signature-hash combination that the user allows.
222 *
223 * We do *not* check whether all certificates in our certificate
224 * chain are signed with an allowed signature-hash pair.
225 * This needs to be done at a later stage.
226 *
227 */
ssl_parse_signature_algorithms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)228 static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
229 const unsigned char *buf,
230 size_t len )
231 {
232 size_t sig_alg_list_size;
233
234 const unsigned char *p;
235 const unsigned char *end = buf + len;
236
237 mbedtls_md_type_t md_cur;
238 mbedtls_pk_type_t sig_cur;
239
240 if ( len < 2 ) {
241 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
242 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
243 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
244 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
245 }
246 sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
247 if( sig_alg_list_size + 2 != len ||
248 sig_alg_list_size % 2 != 0 )
249 {
250 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
251 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
252 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
253 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
254 }
255
256 /* Currently we only guarantee signing the ServerKeyExchange message according
257 * to the constraints specified in this extension (see above), so it suffices
258 * to remember only one suitable hash for each possible signature algorithm.
259 *
260 * This will change when we also consider certificate signatures,
261 * in which case we will need to remember the whole signature-hash
262 * pair list from the extension.
263 */
264
265 for( p = buf + 2; p < end; p += 2 )
266 {
267 /* Silently ignore unknown signature or hash algorithms. */
268
269 if( ( sig_cur = mbedtls_ssl_pk_alg_from_sig( p[1] ) ) == MBEDTLS_PK_NONE )
270 {
271 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext"
272 " unknown sig alg encoding %d", p[1] ) );
273 continue;
274 }
275
276 /* Check if we support the hash the user proposes */
277 md_cur = mbedtls_ssl_md_alg_from_hash( p[0] );
278 if( md_cur == MBEDTLS_MD_NONE )
279 {
280 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
281 " unknown hash alg encoding %d", p[0] ) );
282 continue;
283 }
284
285 if( mbedtls_ssl_check_sig_hash( ssl, md_cur ) == 0 )
286 {
287 mbedtls_ssl_sig_hash_set_add( &ssl->handshake->hash_algs, sig_cur, md_cur );
288 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
289 " match sig %d and hash %d",
290 sig_cur, md_cur ) );
291 }
292 else
293 {
294 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: "
295 "hash alg %d not supported", md_cur ) );
296 }
297 }
298
299 return( 0 );
300 }
301 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
302 MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
303
304 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
305 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_supported_elliptic_curves(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)306 static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
307 const unsigned char *buf,
308 size_t len )
309 {
310 size_t list_size, our_size;
311 const unsigned char *p;
312 const mbedtls_ecp_curve_info *curve_info, **curves;
313
314 if ( len < 2 ) {
315 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
316 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
317 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
318 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
319 }
320 list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
321 if( list_size + 2 != len ||
322 list_size % 2 != 0 )
323 {
324 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
325 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
326 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
327 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
328 }
329
330 /* Should never happen unless client duplicates the extension */
331 if( ssl->handshake->curves != NULL )
332 {
333 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
334 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
335 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
336 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
337 }
338
339 /* Don't allow our peer to make us allocate too much memory,
340 * and leave room for a final 0 */
341 our_size = list_size / 2 + 1;
342 if( our_size > MBEDTLS_ECP_DP_MAX )
343 our_size = MBEDTLS_ECP_DP_MAX;
344
345 if( ( curves = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == NULL )
346 {
347 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
348 MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
349 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
350 }
351
352 ssl->handshake->curves = curves;
353
354 p = buf + 2;
355 while( list_size > 0 && our_size > 1 )
356 {
357 curve_info = mbedtls_ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] );
358
359 if( curve_info != NULL )
360 {
361 *curves++ = curve_info;
362 our_size--;
363 }
364
365 list_size -= 2;
366 p += 2;
367 }
368
369 return( 0 );
370 }
371
ssl_parse_supported_point_formats(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)372 static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl,
373 const unsigned char *buf,
374 size_t len )
375 {
376 size_t list_size;
377 const unsigned char *p;
378
379 if( len == 0 || (size_t)( buf[0] + 1 ) != len )
380 {
381 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
382 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
383 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
384 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
385 }
386 list_size = buf[0];
387
388 p = buf + 1;
389 while( list_size > 0 )
390 {
391 if( p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED ||
392 p[0] == MBEDTLS_ECP_PF_COMPRESSED )
393 {
394 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
395 ssl->handshake->ecdh_ctx.point_format = p[0];
396 #endif
397 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
398 ssl->handshake->ecjpake_ctx.point_format = p[0];
399 #endif
400 MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
401 return( 0 );
402 }
403
404 list_size--;
405 p++;
406 }
407
408 return( 0 );
409 }
410 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
411 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
412
413 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_ecjpake_kkpp(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)414 static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
415 const unsigned char *buf,
416 size_t len )
417 {
418 int ret;
419
420 if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
421 {
422 MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip ecjpake kkpp extension" ) );
423 return( 0 );
424 }
425
426 if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx,
427 buf, len ) ) != 0 )
428 {
429 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
430 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
431 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
432 return( ret );
433 }
434
435 /* Only mark the extension as OK when we're sure it is */
436 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK;
437
438 return( 0 );
439 }
440 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
441
442 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_parse_max_fragment_length_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)443 static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
444 const unsigned char *buf,
445 size_t len )
446 {
447 if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID )
448 {
449 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
450 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
451 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
452 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
453 }
454
455 ssl->session_negotiate->mfl_code = buf[0];
456
457 return( 0 );
458 }
459 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
460
461 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_parse_truncated_hmac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)462 static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
463 const unsigned char *buf,
464 size_t len )
465 {
466 if( len != 0 )
467 {
468 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
469 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
470 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
471 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
472 }
473
474 ((void) buf);
475
476 if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED )
477 ssl->session_negotiate->trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED;
478
479 return( 0 );
480 }
481 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
482
483 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_parse_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)484 static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
485 const unsigned char *buf,
486 size_t len )
487 {
488 if( len != 0 )
489 {
490 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
491 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
492 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
493 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
494 }
495
496 ((void) buf);
497
498 if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED &&
499 ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
500 {
501 ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED;
502 }
503
504 return( 0 );
505 }
506 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
507
508 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_parse_extended_ms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)509 static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
510 const unsigned char *buf,
511 size_t len )
512 {
513 if( len != 0 )
514 {
515 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
516 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
517 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
518 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
519 }
520
521 ((void) buf);
522
523 if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED &&
524 ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
525 {
526 ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
527 }
528
529 return( 0 );
530 }
531 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
532
533 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_parse_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t len)534 static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
535 unsigned char *buf,
536 size_t len )
537 {
538 int ret;
539 mbedtls_ssl_session session;
540
541 mbedtls_ssl_session_init( &session );
542
543 if( ssl->conf->f_ticket_parse == NULL ||
544 ssl->conf->f_ticket_write == NULL )
545 {
546 return( 0 );
547 }
548
549 /* Remember the client asked us to send a new ticket */
550 ssl->handshake->new_session_ticket = 1;
551
552 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %d", len ) );
553
554 if( len == 0 )
555 return( 0 );
556
557 #if defined(MBEDTLS_SSL_RENEGOTIATION)
558 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
559 {
560 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
561 return( 0 );
562 }
563 #endif /* MBEDTLS_SSL_RENEGOTIATION */
564
565 /*
566 * Failures are ok: just ignore the ticket and proceed.
567 */
568 if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session,
569 buf, len ) ) != 0 )
570 {
571 mbedtls_ssl_session_free( &session );
572
573 if( ret == MBEDTLS_ERR_SSL_INVALID_MAC )
574 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) );
575 else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED )
576 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) );
577 else
578 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
579
580 return( 0 );
581 }
582
583 /*
584 * Keep the session ID sent by the client, since we MUST send it back to
585 * inform them we're accepting the ticket (RFC 5077 section 3.4)
586 */
587 session.id_len = ssl->session_negotiate->id_len;
588 memcpy( &session.id, ssl->session_negotiate->id, session.id_len );
589
590 mbedtls_ssl_session_free( ssl->session_negotiate );
591 memcpy( ssl->session_negotiate, &session, sizeof( mbedtls_ssl_session ) );
592
593 /* Zeroize instead of free as we copied the content */
594 mbedtls_platform_zeroize( &session, sizeof( mbedtls_ssl_session ) );
595
596 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
597
598 ssl->handshake->resume = 1;
599
600 /* Don't send a new ticket after all, this one is OK */
601 ssl->handshake->new_session_ticket = 0;
602
603 return( 0 );
604 }
605 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
606
607 #if defined(MBEDTLS_SSL_ALPN)
ssl_parse_alpn_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)608 static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
609 const unsigned char *buf, size_t len )
610 {
611 size_t list_len, cur_len, ours_len;
612 const unsigned char *theirs, *start, *end;
613 const char **ours;
614
615 /* If ALPN not configured, just ignore the extension */
616 if( ssl->conf->alpn_list == NULL )
617 return( 0 );
618
619 /*
620 * opaque ProtocolName<1..2^8-1>;
621 *
622 * struct {
623 * ProtocolName protocol_name_list<2..2^16-1>
624 * } ProtocolNameList;
625 */
626
627 /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
628 if( len < 4 )
629 {
630 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
631 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
632 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
633 }
634
635 list_len = ( buf[0] << 8 ) | buf[1];
636 if( list_len != len - 2 )
637 {
638 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
639 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
640 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
641 }
642
643 /*
644 * Validate peer's list (lengths)
645 */
646 start = buf + 2;
647 end = buf + len;
648 for( theirs = start; theirs != end; theirs += cur_len )
649 {
650 cur_len = *theirs++;
651
652 /* Current identifier must fit in list */
653 if( cur_len > (size_t)( end - theirs ) )
654 {
655 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
656 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
657 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
658 }
659
660 /* Empty strings MUST NOT be included */
661 if( cur_len == 0 )
662 {
663 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
664 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
665 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
666 }
667 }
668
669 /*
670 * Use our order of preference
671 */
672 for( ours = ssl->conf->alpn_list; *ours != NULL; ours++ )
673 {
674 ours_len = strlen( *ours );
675 for( theirs = start; theirs != end; theirs += cur_len )
676 {
677 cur_len = *theirs++;
678
679 if( cur_len == ours_len &&
680 memcmp( theirs, *ours, cur_len ) == 0 )
681 {
682 ssl->alpn_chosen = *ours;
683 return( 0 );
684 }
685 }
686 }
687
688 /* If we get there, no match was found */
689 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
690 MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
691 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
692 }
693 #endif /* MBEDTLS_SSL_ALPN */
694
695 /*
696 * Auxiliary functions for ServerHello parsing and related actions
697 */
698
699 #if defined(MBEDTLS_X509_CRT_PARSE_C)
700 /*
701 * Return 0 if the given key uses one of the acceptable curves, -1 otherwise
702 */
703 #if defined(MBEDTLS_ECDSA_C)
ssl_check_key_curve(mbedtls_pk_context * pk,const mbedtls_ecp_curve_info ** curves)704 static int ssl_check_key_curve( mbedtls_pk_context *pk,
705 const mbedtls_ecp_curve_info **curves )
706 {
707 const mbedtls_ecp_curve_info **crv = curves;
708 mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id;
709
710 while( *crv != NULL )
711 {
712 if( (*crv)->grp_id == grp_id )
713 return( 0 );
714 crv++;
715 }
716
717 return( -1 );
718 }
719 #endif /* MBEDTLS_ECDSA_C */
720
721 /*
722 * Try picking a certificate for this ciphersuite,
723 * return 0 on success and -1 on failure.
724 */
ssl_pick_cert(mbedtls_ssl_context * ssl,const mbedtls_ssl_ciphersuite_t * ciphersuite_info)725 static int ssl_pick_cert( mbedtls_ssl_context *ssl,
726 const mbedtls_ssl_ciphersuite_t * ciphersuite_info )
727 {
728 mbedtls_ssl_key_cert *cur, *list, *fallback = NULL;
729 mbedtls_pk_type_t pk_alg =
730 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
731 uint32_t flags;
732
733 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
734 if( ssl->handshake->sni_key_cert != NULL )
735 list = ssl->handshake->sni_key_cert;
736 else
737 #endif
738 list = ssl->conf->key_cert;
739
740 if( pk_alg == MBEDTLS_PK_NONE )
741 return( 0 );
742
743 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) );
744
745 if( list == NULL )
746 {
747 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server has no certificate" ) );
748 return( -1 );
749 }
750
751 for( cur = list; cur != NULL; cur = cur->next )
752 {
753 MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
754 cur->cert );
755
756 if( ! mbedtls_pk_can_do( &cur->cert->pk, pk_alg ) )
757 {
758 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) );
759 continue;
760 }
761
762 /*
763 * This avoids sending the client a cert it'll reject based on
764 * keyUsage or other extensions.
765 *
766 * It also allows the user to provision different certificates for
767 * different uses based on keyUsage, eg if they want to avoid signing
768 * and decrypting with the same RSA key.
769 */
770 if( mbedtls_ssl_check_cert_usage( cur->cert, ciphersuite_info,
771 MBEDTLS_SSL_IS_SERVER, &flags ) != 0 )
772 {
773 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
774 "(extended) key usage extension" ) );
775 continue;
776 }
777
778 #if defined(MBEDTLS_ECDSA_C)
779 if( pk_alg == MBEDTLS_PK_ECDSA &&
780 ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 0 )
781 {
782 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) );
783 continue;
784 }
785 #endif
786
787 /*
788 * Try to select a SHA-1 certificate for pre-1.2 clients, but still
789 * present them a SHA-higher cert rather than failing if it's the only
790 * one we got that satisfies the other conditions.
791 */
792 if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 &&
793 cur->cert->sig_md != MBEDTLS_MD_SHA1 )
794 {
795 if( fallback == NULL )
796 fallback = cur;
797 {
798 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate not preferred: "
799 "sha-2 with pre-TLS 1.2 client" ) );
800 continue;
801 }
802 }
803
804 /* If we get there, we got a winner */
805 break;
806 }
807
808 if( cur == NULL )
809 cur = fallback;
810
811 /* Do not update ssl->handshake->key_cert unless there is a match */
812 if( cur != NULL )
813 {
814 ssl->handshake->key_cert = cur;
815 MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
816 ssl->handshake->key_cert->cert );
817 return( 0 );
818 }
819
820 return( -1 );
821 }
822 #endif /* MBEDTLS_X509_CRT_PARSE_C */
823
824 /*
825 * Check if a given ciphersuite is suitable for use with our config/keys/etc
826 * Sets ciphersuite_info only if the suite matches.
827 */
ssl_ciphersuite_match(mbedtls_ssl_context * ssl,int suite_id,const mbedtls_ssl_ciphersuite_t ** ciphersuite_info)828 static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id,
829 const mbedtls_ssl_ciphersuite_t **ciphersuite_info )
830 {
831 const mbedtls_ssl_ciphersuite_t *suite_info;
832
833 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
834 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
835 mbedtls_pk_type_t sig_type;
836 #endif
837
838 suite_info = mbedtls_ssl_ciphersuite_from_id( suite_id );
839 if( suite_info == NULL )
840 {
841 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
842 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
843 }
844
845 MBEDTLS_SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %s", suite_info->name ) );
846
847 if( suite_info->min_minor_ver > ssl->minor_ver ||
848 suite_info->max_minor_ver < ssl->minor_ver )
849 {
850 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) );
851 return( 0 );
852 }
853
854 #if defined(MBEDTLS_SSL_PROTO_DTLS)
855 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
856 ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
857 return( 0 );
858 #endif
859
860 #if defined(MBEDTLS_ARC4_C)
861 if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED &&
862 suite_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
863 {
864 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) );
865 return( 0 );
866 }
867 #endif
868
869 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
870 if( suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
871 ( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK ) == 0 )
872 {
873 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: ecjpake "
874 "not configured or ext missing" ) );
875 return( 0 );
876 }
877 #endif
878
879
880 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
881 if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) &&
882 ( ssl->handshake->curves == NULL ||
883 ssl->handshake->curves[0] == NULL ) )
884 {
885 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
886 "no common elliptic curve" ) );
887 return( 0 );
888 }
889 #endif
890
891 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
892 /* If the ciphersuite requires a pre-shared key and we don't
893 * have one, skip it now rather than failing later */
894 if( mbedtls_ssl_ciphersuite_uses_psk( suite_info ) &&
895 ssl->conf->f_psk == NULL &&
896 ( ssl->conf->psk == NULL || ssl->conf->psk_identity == NULL ||
897 ssl->conf->psk_identity_len == 0 || ssl->conf->psk_len == 0 ) )
898 {
899 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) );
900 return( 0 );
901 }
902 #endif
903
904 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
905 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
906 /* If the ciphersuite requires signing, check whether
907 * a suitable hash algorithm is present. */
908 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
909 {
910 sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
911 if( sig_type != MBEDTLS_PK_NONE &&
912 mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == MBEDTLS_MD_NONE )
913 {
914 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
915 "for signature algorithm %d", sig_type ) );
916 return( 0 );
917 }
918 }
919
920 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
921 MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
922
923 #if defined(MBEDTLS_X509_CRT_PARSE_C)
924 /*
925 * Final check: if ciphersuite requires us to have a
926 * certificate/key of a particular type:
927 * - select the appropriate certificate if we have one, or
928 * - try the next ciphersuite if we don't
929 * This must be done last since we modify the key_cert list.
930 */
931 if( ssl_pick_cert( ssl, suite_info ) != 0 )
932 {
933 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
934 "no suitable certificate" ) );
935 return( 0 );
936 }
937 #endif
938
939 *ciphersuite_info = suite_info;
940 return( 0 );
941 }
942
943 #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
ssl_parse_client_hello_v2(mbedtls_ssl_context * ssl)944 static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
945 {
946 int ret, got_common_suite;
947 unsigned int i, j;
948 size_t n;
949 unsigned int ciph_len, sess_len, chal_len;
950 unsigned char *buf, *p;
951 const int *ciphersuites;
952 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
953
954 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
955
956 #if defined(MBEDTLS_SSL_RENEGOTIATION)
957 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
958 {
959 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
960 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
961 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
962 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
963 }
964 #endif /* MBEDTLS_SSL_RENEGOTIATION */
965
966 buf = ssl->in_hdr;
967
968 MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, 5 );
969
970 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
971 buf[2] ) );
972 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
973 ( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
974 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
975 buf[3], buf[4] ) );
976
977 /*
978 * SSLv2 Client Hello
979 *
980 * Record layer:
981 * 0 . 1 message length
982 *
983 * SSL layer:
984 * 2 . 2 message type
985 * 3 . 4 protocol version
986 */
987 if( buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO ||
988 buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3 )
989 {
990 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
991 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
992 }
993
994 n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
995
996 if( n < 17 || n > 512 )
997 {
998 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
999 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1000 }
1001
1002 ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3;
1003 ssl->minor_ver = ( buf[4] <= ssl->conf->max_minor_ver )
1004 ? buf[4] : ssl->conf->max_minor_ver;
1005
1006 if( ssl->minor_ver < ssl->conf->min_minor_ver )
1007 {
1008 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
1009 " [%d:%d] < [%d:%d]",
1010 ssl->major_ver, ssl->minor_ver,
1011 ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
1012
1013 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1014 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1015 return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
1016 }
1017
1018 ssl->handshake->max_major_ver = buf[3];
1019 ssl->handshake->max_minor_ver = buf[4];
1020
1021 if( ( ret = mbedtls_ssl_fetch_input( ssl, 2 + n ) ) != 0 )
1022 {
1023 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1024 return( ret );
1025 }
1026
1027 ssl->handshake->update_checksum( ssl, buf + 2, n );
1028
1029 buf = ssl->in_msg;
1030 n = ssl->in_left - 5;
1031
1032 /*
1033 * 0 . 1 ciphersuitelist length
1034 * 2 . 3 session id length
1035 * 4 . 5 challenge length
1036 * 6 . .. ciphersuitelist
1037 * .. . .. session id
1038 * .. . .. challenge
1039 */
1040 MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, n );
1041
1042 ciph_len = ( buf[0] << 8 ) | buf[1];
1043 sess_len = ( buf[2] << 8 ) | buf[3];
1044 chal_len = ( buf[4] << 8 ) | buf[5];
1045
1046 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d",
1047 ciph_len, sess_len, chal_len ) );
1048
1049 /*
1050 * Make sure each parameter length is valid
1051 */
1052 if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
1053 {
1054 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1055 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1056 }
1057
1058 if( sess_len > 32 )
1059 {
1060 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1061 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1062 }
1063
1064 if( chal_len < 8 || chal_len > 32 )
1065 {
1066 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1067 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1068 }
1069
1070 if( n != 6 + ciph_len + sess_len + chal_len )
1071 {
1072 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1073 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1074 }
1075
1076 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
1077 buf + 6, ciph_len );
1078 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id",
1079 buf + 6 + ciph_len, sess_len );
1080 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, challenge",
1081 buf + 6 + ciph_len + sess_len, chal_len );
1082
1083 p = buf + 6 + ciph_len;
1084 ssl->session_negotiate->id_len = sess_len;
1085 memset( ssl->session_negotiate->id, 0,
1086 sizeof( ssl->session_negotiate->id ) );
1087 memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len );
1088
1089 p += sess_len;
1090 memset( ssl->handshake->randbytes, 0, 64 );
1091 memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
1092
1093 /*
1094 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
1095 */
1096 for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
1097 {
1098 if( p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
1099 {
1100 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
1101 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1102 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1103 {
1104 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
1105 "during renegotiation" ) );
1106
1107 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1108 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1109 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1110 }
1111 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1112 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
1113 break;
1114 }
1115 }
1116
1117 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
1118 for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
1119 {
1120 if( p[0] == 0 &&
1121 p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
1122 p[2] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
1123 {
1124 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
1125
1126 if( ssl->minor_ver < ssl->conf->max_minor_ver )
1127 {
1128 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
1129
1130 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1131 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
1132
1133 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1134 }
1135
1136 break;
1137 }
1138 }
1139 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
1140
1141 got_common_suite = 0;
1142 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
1143 ciphersuite_info = NULL;
1144 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
1145 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
1146 for( i = 0; ciphersuites[i] != 0; i++ )
1147 #else
1148 for( i = 0; ciphersuites[i] != 0; i++ )
1149 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
1150 #endif
1151 {
1152 if( p[0] != 0 ||
1153 p[1] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
1154 p[2] != ( ( ciphersuites[i] ) & 0xFF ) )
1155 continue;
1156
1157 got_common_suite = 1;
1158
1159 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
1160 &ciphersuite_info ) ) != 0 )
1161 return( ret );
1162
1163 if( ciphersuite_info != NULL )
1164 goto have_ciphersuite_v2;
1165 }
1166
1167 if( got_common_suite )
1168 {
1169 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
1170 "but none of them usable" ) );
1171 return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
1172 }
1173 else
1174 {
1175 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
1176 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
1177 }
1178
1179 have_ciphersuite_v2:
1180 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
1181
1182 ssl->session_negotiate->ciphersuite = ciphersuites[i];
1183 ssl->transform_negotiate->ciphersuite_info = ciphersuite_info;
1184
1185 /*
1186 * SSLv2 Client Hello relevant renegotiation security checks
1187 */
1188 if( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
1189 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
1190 {
1191 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
1192 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1193 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1194 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1195 }
1196
1197 ssl->in_left = 0;
1198 ssl->state++;
1199
1200 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) );
1201
1202 return( 0 );
1203 }
1204 #endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
1205
1206 /* This function doesn't alert on errors that happen early during
1207 ClientHello parsing because they might indicate that the client is
1208 not talking SSL/TLS at all and would not understand our alert. */
ssl_parse_client_hello(mbedtls_ssl_context * ssl)1209 static int ssl_parse_client_hello( mbedtls_ssl_context *ssl )
1210 {
1211 int ret, got_common_suite;
1212 size_t i, j;
1213 size_t ciph_offset, comp_offset, ext_offset;
1214 size_t msg_len, ciph_len, sess_len, comp_len, ext_len;
1215 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1216 size_t cookie_offset, cookie_len;
1217 #endif
1218 unsigned char *buf, *p, *ext;
1219 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1220 int renegotiation_info_seen = 0;
1221 #endif
1222 int handshake_failure = 0;
1223 const int *ciphersuites;
1224 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
1225 int major, minor;
1226
1227 /* If there is no signature-algorithm extension present,
1228 * we need to fall back to the default values for allowed
1229 * signature-hash pairs. */
1230 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1231 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
1232 int sig_hash_alg_ext_present = 0;
1233 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1234 MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
1235
1236 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
1237
1238 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1239 read_record_header:
1240 #endif
1241 /*
1242 * If renegotiating, then the input was read with mbedtls_ssl_read_record(),
1243 * otherwise read it ourselves manually in order to support SSLv2
1244 * ClientHello, which doesn't use the same record layer format.
1245 */
1246 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1247 if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
1248 #endif
1249 {
1250 if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
1251 {
1252 /* No alert on a read error. */
1253 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1254 return( ret );
1255 }
1256 }
1257
1258 buf = ssl->in_hdr;
1259
1260 #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
1261 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1262 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM )
1263 #endif
1264 if( ( buf[0] & 0x80 ) != 0 )
1265 return( ssl_parse_client_hello_v2( ssl ) );
1266 #endif
1267
1268 MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_hdr_len( ssl ) );
1269
1270 /*
1271 * SSLv3/TLS Client Hello
1272 *
1273 * Record layer:
1274 * 0 . 0 message type
1275 * 1 . 2 protocol version
1276 * 3 . 11 DTLS: epoch + record sequence number
1277 * 3 . 4 message length
1278 */
1279 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d",
1280 buf[0] ) );
1281
1282 if( buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE )
1283 {
1284 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1285 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1286 }
1287
1288 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d",
1289 ( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) );
1290
1291 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, protocol version: [%d:%d]",
1292 buf[1], buf[2] ) );
1293
1294 mbedtls_ssl_read_version( &major, &minor, ssl->conf->transport, buf + 1 );
1295
1296 /* According to RFC 5246 Appendix E.1, the version here is typically
1297 * "{03,00}, the lowest version number supported by the client, [or] the
1298 * value of ClientHello.client_version", so the only meaningful check here
1299 * is the major version shouldn't be less than 3 */
1300 if( major < MBEDTLS_SSL_MAJOR_VERSION_3 )
1301 {
1302 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1303 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1304 }
1305
1306 /* For DTLS if this is the initial handshake, remember the client sequence
1307 * number to use it in our next message (RFC 6347 4.2.1) */
1308 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1309 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM
1310 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1311 && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
1312 #endif
1313 )
1314 {
1315 /* Epoch should be 0 for initial handshakes */
1316 if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 )
1317 {
1318 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1319 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1320 }
1321
1322 memcpy( ssl->cur_out_ctr + 2, ssl->in_ctr + 2, 6 );
1323
1324 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1325 if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
1326 {
1327 MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record, discarding" ) );
1328 ssl->next_record_offset = 0;
1329 ssl->in_left = 0;
1330 goto read_record_header;
1331 }
1332
1333 /* No MAC to check yet, so we can update right now */
1334 mbedtls_ssl_dtls_replay_update( ssl );
1335 #endif
1336 }
1337 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1338
1339 msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1];
1340
1341 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1342 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
1343 {
1344 /* Set by mbedtls_ssl_read_record() */
1345 msg_len = ssl->in_hslen;
1346 }
1347 else
1348 #endif
1349 {
1350 if( msg_len > MBEDTLS_SSL_IN_CONTENT_LEN )
1351 {
1352 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1353 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1354 }
1355
1356 if( ( ret = mbedtls_ssl_fetch_input( ssl,
1357 mbedtls_ssl_hdr_len( ssl ) + msg_len ) ) != 0 )
1358 {
1359 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1360 return( ret );
1361 }
1362
1363 /* Done reading this record, get ready for the next one */
1364 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1365 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1366 ssl->next_record_offset = msg_len + mbedtls_ssl_hdr_len( ssl );
1367 else
1368 #endif
1369 ssl->in_left = 0;
1370 }
1371
1372 buf = ssl->in_msg;
1373
1374 MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, msg_len );
1375
1376 ssl->handshake->update_checksum( ssl, buf, msg_len );
1377
1378 /*
1379 * Handshake layer:
1380 * 0 . 0 handshake type
1381 * 1 . 3 handshake length
1382 * 4 . 5 DTLS only: message seqence number
1383 * 6 . 8 DTLS only: fragment offset
1384 * 9 . 11 DTLS only: fragment length
1385 */
1386 if( msg_len < mbedtls_ssl_hs_hdr_len( ssl ) )
1387 {
1388 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1389 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1390 }
1391
1392 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
1393
1394 if( buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO )
1395 {
1396 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1397 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1398 }
1399
1400 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
1401 ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
1402
1403 /* We don't support fragmentation of ClientHello (yet?) */
1404 if( buf[1] != 0 ||
1405 msg_len != mbedtls_ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) )
1406 {
1407 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1408 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1409 }
1410
1411 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1412 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1413 {
1414 /*
1415 * Copy the client's handshake message_seq on initial handshakes,
1416 * check sequence number on renego.
1417 */
1418 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1419 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1420 {
1421 /* This couldn't be done in ssl_prepare_handshake_record() */
1422 unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
1423 ssl->in_msg[5];
1424
1425 if( cli_msg_seq != ssl->handshake->in_msg_seq )
1426 {
1427 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message_seq: "
1428 "%d (expected %d)", cli_msg_seq,
1429 ssl->handshake->in_msg_seq ) );
1430 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1431 }
1432
1433 ssl->handshake->in_msg_seq++;
1434 }
1435 else
1436 #endif
1437 {
1438 unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
1439 ssl->in_msg[5];
1440 ssl->handshake->out_msg_seq = cli_msg_seq;
1441 ssl->handshake->in_msg_seq = cli_msg_seq + 1;
1442 }
1443
1444 /*
1445 * For now we don't support fragmentation, so make sure
1446 * fragment_offset == 0 and fragment_length == length
1447 */
1448 if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
1449 memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
1450 {
1451 MBEDTLS_SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) );
1452 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
1453 }
1454 }
1455 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1456
1457 buf += mbedtls_ssl_hs_hdr_len( ssl );
1458 msg_len -= mbedtls_ssl_hs_hdr_len( ssl );
1459
1460 /*
1461 * ClientHello layer:
1462 * 0 . 1 protocol version
1463 * 2 . 33 random bytes (starting with 4 bytes of Unix time)
1464 * 34 . 35 session id length (1 byte)
1465 * 35 . 34+x session id
1466 * 35+x . 35+x DTLS only: cookie length (1 byte)
1467 * 36+x . .. DTLS only: cookie
1468 * .. . .. ciphersuite list length (2 bytes)
1469 * .. . .. ciphersuite list
1470 * .. . .. compression alg. list length (1 byte)
1471 * .. . .. compression alg. list
1472 * .. . .. extensions length (2 bytes, optional)
1473 * .. . .. extensions (optional)
1474 */
1475
1476 /*
1477 * Minimal length (with everything empty and extensions omitted) is
1478 * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
1479 * read at least up to session id length without worrying.
1480 */
1481 if( msg_len < 38 )
1482 {
1483 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1484 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1485 }
1486
1487 /*
1488 * Check and save the protocol version
1489 */
1490 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 );
1491
1492 mbedtls_ssl_read_version( &ssl->major_ver, &ssl->minor_ver,
1493 ssl->conf->transport, buf );
1494
1495 ssl->handshake->max_major_ver = ssl->major_ver;
1496 ssl->handshake->max_minor_ver = ssl->minor_ver;
1497
1498 if( ssl->major_ver < ssl->conf->min_major_ver ||
1499 ssl->minor_ver < ssl->conf->min_minor_ver )
1500 {
1501 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
1502 " [%d:%d] < [%d:%d]",
1503 ssl->major_ver, ssl->minor_ver,
1504 ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
1505 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1506 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1507 return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
1508 }
1509
1510 if( ssl->major_ver > ssl->conf->max_major_ver )
1511 {
1512 ssl->major_ver = ssl->conf->max_major_ver;
1513 ssl->minor_ver = ssl->conf->max_minor_ver;
1514 }
1515 else if( ssl->minor_ver > ssl->conf->max_minor_ver )
1516 ssl->minor_ver = ssl->conf->max_minor_ver;
1517
1518 /*
1519 * Save client random (inc. Unix time)
1520 */
1521 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 );
1522
1523 memcpy( ssl->handshake->randbytes, buf + 2, 32 );
1524
1525 /*
1526 * Check the session ID length and save session ID
1527 */
1528 sess_len = buf[34];
1529
1530 if( sess_len > sizeof( ssl->session_negotiate->id ) ||
1531 sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */
1532 {
1533 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1534 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1535 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1536 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1537 }
1538
1539 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len );
1540
1541 ssl->session_negotiate->id_len = sess_len;
1542 memset( ssl->session_negotiate->id, 0,
1543 sizeof( ssl->session_negotiate->id ) );
1544 memcpy( ssl->session_negotiate->id, buf + 35,
1545 ssl->session_negotiate->id_len );
1546
1547 /*
1548 * Check the cookie length and content
1549 */
1550 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1551 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1552 {
1553 cookie_offset = 35 + sess_len;
1554 cookie_len = buf[cookie_offset];
1555
1556 if( cookie_offset + 1 + cookie_len + 2 > msg_len )
1557 {
1558 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1559 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1560 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1561 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1562 }
1563
1564 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie",
1565 buf + cookie_offset + 1, cookie_len );
1566
1567 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
1568 if( ssl->conf->f_cookie_check != NULL
1569 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1570 && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
1571 #endif
1572 )
1573 {
1574 if( ssl->conf->f_cookie_check( ssl->conf->p_cookie,
1575 buf + cookie_offset + 1, cookie_len,
1576 ssl->cli_id, ssl->cli_id_len ) != 0 )
1577 {
1578 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification failed" ) );
1579 ssl->handshake->verify_cookie_len = 1;
1580 }
1581 else
1582 {
1583 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) );
1584 ssl->handshake->verify_cookie_len = 0;
1585 }
1586 }
1587 else
1588 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
1589 {
1590 /* We know we didn't send a cookie, so it should be empty */
1591 if( cookie_len != 0 )
1592 {
1593 /* This may be an attacker's probe, so don't send an alert */
1594 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1595 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1596 }
1597
1598 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification skipped" ) );
1599 }
1600
1601 /*
1602 * Check the ciphersuitelist length (will be parsed later)
1603 */
1604 ciph_offset = cookie_offset + 1 + cookie_len;
1605 }
1606 else
1607 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1608 ciph_offset = 35 + sess_len;
1609
1610 ciph_len = ( buf[ciph_offset + 0] << 8 )
1611 | ( buf[ciph_offset + 1] );
1612
1613 if( ciph_len < 2 ||
1614 ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
1615 ( ciph_len % 2 ) != 0 )
1616 {
1617 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1618 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1619 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1620 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1621 }
1622
1623 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
1624 buf + ciph_offset + 2, ciph_len );
1625
1626 /*
1627 * Check the compression algorithms length and pick one
1628 */
1629 comp_offset = ciph_offset + 2 + ciph_len;
1630
1631 comp_len = buf[comp_offset];
1632
1633 if( comp_len < 1 ||
1634 comp_len > 16 ||
1635 comp_len + comp_offset + 1 > msg_len )
1636 {
1637 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1638 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1639 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1640 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1641 }
1642
1643 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, compression",
1644 buf + comp_offset + 1, comp_len );
1645
1646 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
1647 #if defined(MBEDTLS_ZLIB_SUPPORT)
1648 for( i = 0; i < comp_len; ++i )
1649 {
1650 if( buf[comp_offset + 1 + i] == MBEDTLS_SSL_COMPRESS_DEFLATE )
1651 {
1652 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_DEFLATE;
1653 break;
1654 }
1655 }
1656 #endif
1657
1658 /* See comments in ssl_write_client_hello() */
1659 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1660 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1661 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
1662 #endif
1663
1664 /* Do not parse the extensions if the protocol is SSLv3 */
1665 #if defined(MBEDTLS_SSL_PROTO_SSL3)
1666 if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
1667 {
1668 #endif
1669 /*
1670 * Check the extension length
1671 */
1672 ext_offset = comp_offset + 1 + comp_len;
1673 if( msg_len > ext_offset )
1674 {
1675 if( msg_len < ext_offset + 2 )
1676 {
1677 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1678 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1679 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1680 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1681 }
1682
1683 ext_len = ( buf[ext_offset + 0] << 8 )
1684 | ( buf[ext_offset + 1] );
1685
1686 if( ( ext_len > 0 && ext_len < 4 ) ||
1687 msg_len != ext_offset + 2 + ext_len )
1688 {
1689 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1690 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1691 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1692 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1693 }
1694 }
1695 else
1696 ext_len = 0;
1697
1698 ext = buf + ext_offset + 2;
1699 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len );
1700
1701 while( ext_len != 0 )
1702 {
1703 unsigned int ext_id;
1704 unsigned int ext_size;
1705 if ( ext_len < 4 ) {
1706 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1707 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1708 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1709 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1710 }
1711 ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) );
1712 ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) );
1713
1714 if( ext_size + 4 > ext_len )
1715 {
1716 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1717 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1718 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1719 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1720 }
1721 switch( ext_id )
1722 {
1723 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
1724 case MBEDTLS_TLS_EXT_SERVERNAME:
1725 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
1726 if( ssl->conf->f_sni == NULL )
1727 break;
1728
1729 ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size );
1730 if( ret != 0 )
1731 return( ret );
1732 break;
1733 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
1734
1735 case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO:
1736 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
1737 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1738 renegotiation_info_seen = 1;
1739 #endif
1740
1741 ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
1742 if( ret != 0 )
1743 return( ret );
1744 break;
1745
1746 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1747 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
1748 case MBEDTLS_TLS_EXT_SIG_ALG:
1749 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
1750
1751 ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
1752 if( ret != 0 )
1753 return( ret );
1754
1755 sig_hash_alg_ext_present = 1;
1756 break;
1757 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1758 MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
1759
1760 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
1761 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1762 case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
1763 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
1764
1765 ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
1766 if( ret != 0 )
1767 return( ret );
1768 break;
1769
1770 case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS:
1771 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) );
1772 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
1773
1774 ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size );
1775 if( ret != 0 )
1776 return( ret );
1777 break;
1778 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
1779 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1780
1781 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1782 case MBEDTLS_TLS_EXT_ECJPAKE_KKPP:
1783 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ecjpake kkpp extension" ) );
1784
1785 ret = ssl_parse_ecjpake_kkpp( ssl, ext + 4, ext_size );
1786 if( ret != 0 )
1787 return( ret );
1788 break;
1789 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1790
1791 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
1792 case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH:
1793 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
1794
1795 ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size );
1796 if( ret != 0 )
1797 return( ret );
1798 break;
1799 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
1800
1801 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
1802 case MBEDTLS_TLS_EXT_TRUNCATED_HMAC:
1803 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
1804
1805 ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size );
1806 if( ret != 0 )
1807 return( ret );
1808 break;
1809 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
1810
1811 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
1812 case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
1813 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
1814
1815 ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
1816 if( ret != 0 )
1817 return( ret );
1818 break;
1819 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
1820
1821 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
1822 case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET:
1823 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
1824
1825 ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size );
1826 if( ret != 0 )
1827 return( ret );
1828 break;
1829 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
1830
1831 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
1832 case MBEDTLS_TLS_EXT_SESSION_TICKET:
1833 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) );
1834
1835 ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size );
1836 if( ret != 0 )
1837 return( ret );
1838 break;
1839 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
1840
1841 #if defined(MBEDTLS_SSL_ALPN)
1842 case MBEDTLS_TLS_EXT_ALPN:
1843 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );
1844
1845 ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
1846 if( ret != 0 )
1847 return( ret );
1848 break;
1849 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
1850
1851 default:
1852 MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)",
1853 ext_id ) );
1854 }
1855
1856 ext_len -= 4 + ext_size;
1857 ext += 4 + ext_size;
1858
1859 if( ext_len > 0 && ext_len < 4 )
1860 {
1861 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1862 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1863 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1864 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1865 }
1866 }
1867 #if defined(MBEDTLS_SSL_PROTO_SSL3)
1868 }
1869 #endif
1870
1871 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
1872 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
1873 {
1874 if( p[0] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
1875 p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
1876 {
1877 MBEDTLS_SSL_DEBUG_MSG( 2, ( "received FALLBACK_SCSV" ) );
1878
1879 if( ssl->minor_ver < ssl->conf->max_minor_ver )
1880 {
1881 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
1882
1883 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1884 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
1885
1886 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1887 }
1888
1889 break;
1890 }
1891 }
1892 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
1893
1894 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1895 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
1896
1897 /*
1898 * Try to fall back to default hash SHA1 if the client
1899 * hasn't provided any preferred signature-hash combinations.
1900 */
1901 if( sig_hash_alg_ext_present == 0 )
1902 {
1903 mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1;
1904
1905 if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 )
1906 md_default = MBEDTLS_MD_NONE;
1907
1908 mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default );
1909 }
1910
1911 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1912 MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
1913
1914 /*
1915 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
1916 */
1917 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
1918 {
1919 if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
1920 {
1921 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
1922 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1923 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1924 {
1925 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
1926 "during renegotiation" ) );
1927 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1928 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1929 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1930 }
1931 #endif
1932 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
1933 break;
1934 }
1935 }
1936
1937 /*
1938 * Renegotiation security checks
1939 */
1940 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
1941 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
1942 {
1943 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
1944 handshake_failure = 1;
1945 }
1946 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1947 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
1948 ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
1949 renegotiation_info_seen == 0 )
1950 {
1951 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
1952 handshake_failure = 1;
1953 }
1954 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
1955 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
1956 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION )
1957 {
1958 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
1959 handshake_failure = 1;
1960 }
1961 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
1962 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
1963 renegotiation_info_seen == 1 )
1964 {
1965 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
1966 handshake_failure = 1;
1967 }
1968 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1969
1970 if( handshake_failure == 1 )
1971 {
1972 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1973 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1974 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1975 }
1976
1977 /*
1978 * Search for a matching ciphersuite
1979 * (At the end because we need information from the EC-based extensions
1980 * and certificate from the SNI callback triggered by the SNI extension.)
1981 */
1982 got_common_suite = 0;
1983 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
1984 ciphersuite_info = NULL;
1985 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
1986 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
1987 for( i = 0; ciphersuites[i] != 0; i++ )
1988 #else
1989 for( i = 0; ciphersuites[i] != 0; i++ )
1990 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
1991 #endif
1992 {
1993 if( p[0] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
1994 p[1] != ( ( ciphersuites[i] ) & 0xFF ) )
1995 continue;
1996
1997 got_common_suite = 1;
1998
1999 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
2000 &ciphersuite_info ) ) != 0 )
2001 return( ret );
2002
2003 if( ciphersuite_info != NULL )
2004 goto have_ciphersuite;
2005 }
2006
2007 if( got_common_suite )
2008 {
2009 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
2010 "but none of them usable" ) );
2011 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2012 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2013 return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
2014 }
2015 else
2016 {
2017 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
2018 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2019 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2020 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
2021 }
2022
2023 have_ciphersuite:
2024 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
2025
2026 ssl->session_negotiate->ciphersuite = ciphersuites[i];
2027 ssl->transform_negotiate->ciphersuite_info = ciphersuite_info;
2028
2029 ssl->state++;
2030
2031 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2032 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
2033 mbedtls_ssl_recv_flight_completed( ssl );
2034 #endif
2035
2036 /* Debugging-only output for testsuite */
2037 #if defined(MBEDTLS_DEBUG_C) && \
2038 defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2039 defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
2040 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
2041 {
2042 mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info );
2043 if( sig_alg != MBEDTLS_PK_NONE )
2044 {
2045 mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
2046 sig_alg );
2047 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
2048 mbedtls_ssl_hash_from_md_alg( md_alg ) ) );
2049 }
2050 else
2051 {
2052 MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm "
2053 "%d - should not happen", sig_alg ) );
2054 }
2055 }
2056 #endif
2057
2058 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
2059
2060 return( 0 );
2061 }
2062
2063 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_write_truncated_hmac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2064 static void ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl,
2065 unsigned char *buf,
2066 size_t *olen )
2067 {
2068 unsigned char *p = buf;
2069
2070 if( ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED )
2071 {
2072 *olen = 0;
2073 return;
2074 }
2075
2076 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) );
2077
2078 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
2079 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC ) & 0xFF );
2080
2081 *p++ = 0x00;
2082 *p++ = 0x00;
2083
2084 *olen = 4;
2085 }
2086 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2087
2088 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2089 static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
2090 unsigned char *buf,
2091 size_t *olen )
2092 {
2093 unsigned char *p = buf;
2094 const mbedtls_ssl_ciphersuite_t *suite = NULL;
2095 const mbedtls_cipher_info_t *cipher = NULL;
2096
2097 if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ||
2098 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2099 {
2100 *olen = 0;
2101 return;
2102 }
2103
2104 /*
2105 * RFC 7366: "If a server receives an encrypt-then-MAC request extension
2106 * from a client and then selects a stream or Authenticated Encryption
2107 * with Associated Data (AEAD) ciphersuite, it MUST NOT send an
2108 * encrypt-then-MAC response extension back to the client."
2109 */
2110 if( ( suite = mbedtls_ssl_ciphersuite_from_id(
2111 ssl->session_negotiate->ciphersuite ) ) == NULL ||
2112 ( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL ||
2113 cipher->mode != MBEDTLS_MODE_CBC )
2114 {
2115 *olen = 0;
2116 return;
2117 }
2118
2119 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
2120
2121 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
2122 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
2123
2124 *p++ = 0x00;
2125 *p++ = 0x00;
2126
2127 *olen = 4;
2128 }
2129 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2130
2131 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2132 static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
2133 unsigned char *buf,
2134 size_t *olen )
2135 {
2136 unsigned char *p = buf;
2137
2138 if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED ||
2139 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2140 {
2141 *olen = 0;
2142 return;
2143 }
2144
2145 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
2146 "extension" ) );
2147
2148 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
2149 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF );
2150
2151 *p++ = 0x00;
2152 *p++ = 0x00;
2153
2154 *olen = 4;
2155 }
2156 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2157
2158 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2159 static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
2160 unsigned char *buf,
2161 size_t *olen )
2162 {
2163 unsigned char *p = buf;
2164
2165 if( ssl->handshake->new_session_ticket == 0 )
2166 {
2167 *olen = 0;
2168 return;
2169 }
2170
2171 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
2172
2173 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
2174 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET ) & 0xFF );
2175
2176 *p++ = 0x00;
2177 *p++ = 0x00;
2178
2179 *olen = 4;
2180 }
2181 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2182
ssl_write_renegotiation_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2183 static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
2184 unsigned char *buf,
2185 size_t *olen )
2186 {
2187 unsigned char *p = buf;
2188
2189 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION )
2190 {
2191 *olen = 0;
2192 return;
2193 }
2194
2195 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) );
2196
2197 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF );
2198 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ) & 0xFF );
2199
2200 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2201 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2202 {
2203 *p++ = 0x00;
2204 *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF;
2205 *p++ = ssl->verify_data_len * 2 & 0xFF;
2206
2207 memcpy( p, ssl->peer_verify_data, ssl->verify_data_len );
2208 p += ssl->verify_data_len;
2209 memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
2210 p += ssl->verify_data_len;
2211 }
2212 else
2213 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2214 {
2215 *p++ = 0x00;
2216 *p++ = 0x01;
2217 *p++ = 0x00;
2218 }
2219
2220 *olen = p - buf;
2221 }
2222
2223 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2224 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
2225 unsigned char *buf,
2226 size_t *olen )
2227 {
2228 unsigned char *p = buf;
2229
2230 if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE )
2231 {
2232 *olen = 0;
2233 return;
2234 }
2235
2236 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
2237
2238 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF );
2239 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF );
2240
2241 *p++ = 0x00;
2242 *p++ = 1;
2243
2244 *p++ = ssl->session_negotiate->mfl_code;
2245
2246 *olen = 5;
2247 }
2248 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2249
2250 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2251 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_supported_point_formats_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2252 static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
2253 unsigned char *buf,
2254 size_t *olen )
2255 {
2256 unsigned char *p = buf;
2257 ((void) ssl);
2258
2259 if( ( ssl->handshake->cli_exts &
2260 MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
2261 {
2262 *olen = 0;
2263 return;
2264 }
2265
2266 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
2267
2268 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
2269 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF );
2270
2271 *p++ = 0x00;
2272 *p++ = 2;
2273
2274 *p++ = 1;
2275 *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
2276
2277 *olen = 6;
2278 }
2279 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2280
2281 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2282 static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
2283 unsigned char *buf,
2284 size_t *olen )
2285 {
2286 int ret;
2287 unsigned char *p = buf;
2288 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2289 size_t kkpp_len;
2290
2291 *olen = 0;
2292
2293 /* Skip costly computation if not needed */
2294 if( ssl->transform_negotiate->ciphersuite_info->key_exchange !=
2295 MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2296 return;
2297
2298 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, ecjpake kkpp extension" ) );
2299
2300 if( end - p < 4 )
2301 {
2302 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2303 return;
2304 }
2305
2306 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP >> 8 ) & 0xFF );
2307 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ) & 0xFF );
2308
2309 ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
2310 p + 2, end - p - 2, &kkpp_len,
2311 ssl->conf->f_rng, ssl->conf->p_rng );
2312 if( ret != 0 )
2313 {
2314 MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
2315 return;
2316 }
2317
2318 *p++ = (unsigned char)( ( kkpp_len >> 8 ) & 0xFF );
2319 *p++ = (unsigned char)( ( kkpp_len ) & 0xFF );
2320
2321 *olen = kkpp_len + 4;
2322 }
2323 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2324
2325 #if defined(MBEDTLS_SSL_ALPN )
ssl_write_alpn_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2326 static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
2327 unsigned char *buf, size_t *olen )
2328 {
2329 if( ssl->alpn_chosen == NULL )
2330 {
2331 *olen = 0;
2332 return;
2333 }
2334
2335 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
2336
2337 /*
2338 * 0 . 1 ext identifier
2339 * 2 . 3 ext length
2340 * 4 . 5 protocol list length
2341 * 6 . 6 protocol name length
2342 * 7 . 7+n protocol name
2343 */
2344 buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF );
2345 buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN ) & 0xFF );
2346
2347 *olen = 7 + strlen( ssl->alpn_chosen );
2348
2349 buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
2350 buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF );
2351
2352 buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
2353 buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF );
2354
2355 buf[6] = (unsigned char)( ( ( *olen - 7 ) ) & 0xFF );
2356
2357 memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
2358 }
2359 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
2360
2361 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
ssl_write_hello_verify_request(mbedtls_ssl_context * ssl)2362 static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
2363 {
2364 int ret;
2365 unsigned char *p = ssl->out_msg + 4;
2366 unsigned char *cookie_len_byte;
2367
2368 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) );
2369
2370 /*
2371 * struct {
2372 * ProtocolVersion server_version;
2373 * opaque cookie<0..2^8-1>;
2374 * } HelloVerifyRequest;
2375 */
2376
2377 /* The RFC is not clear on this point, but sending the actual negotiated
2378 * version looks like the most interoperable thing to do. */
2379 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2380 ssl->conf->transport, p );
2381 MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 );
2382 p += 2;
2383
2384 /* If we get here, f_cookie_check is not null */
2385 if( ssl->conf->f_cookie_write == NULL )
2386 {
2387 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) );
2388 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2389 }
2390
2391 /* Skip length byte until we know the length */
2392 cookie_len_byte = p++;
2393
2394 if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
2395 &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
2396 ssl->cli_id, ssl->cli_id_len ) ) != 0 )
2397 {
2398 MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
2399 return( ret );
2400 }
2401
2402 *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) );
2403
2404 MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte );
2405
2406 ssl->out_msglen = p - ssl->out_msg;
2407 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2408 ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
2409
2410 ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
2411
2412 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
2413 {
2414 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
2415 return( ret );
2416 }
2417
2418 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2419 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2420 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
2421 {
2422 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
2423 return( ret );
2424 }
2425 #endif /* MBEDTLS_SSL_PROTO_DTLS */
2426
2427 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
2428
2429 return( 0 );
2430 }
2431 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2432
ssl_write_server_hello(mbedtls_ssl_context * ssl)2433 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
2434 {
2435 #if defined(MBEDTLS_HAVE_TIME)
2436 mbedtls_time_t t;
2437 #endif
2438 int ret;
2439 size_t olen, ext_len = 0, n;
2440 unsigned char *buf, *p;
2441
2442 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
2443
2444 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
2445 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2446 ssl->handshake->verify_cookie_len != 0 )
2447 {
2448 MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) );
2449 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2450
2451 return( ssl_write_hello_verify_request( ssl ) );
2452 }
2453 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2454
2455 if( ssl->conf->f_rng == NULL )
2456 {
2457 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
2458 return( MBEDTLS_ERR_SSL_NO_RNG );
2459 }
2460
2461 /*
2462 * 0 . 0 handshake type
2463 * 1 . 3 handshake length
2464 * 4 . 5 protocol version
2465 * 6 . 9 UNIX time()
2466 * 10 . 37 random bytes
2467 */
2468 buf = ssl->out_msg;
2469 p = buf + 4;
2470
2471 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2472 ssl->conf->transport, p );
2473 p += 2;
2474
2475 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
2476 buf[4], buf[5] ) );
2477
2478 #if defined(MBEDTLS_HAVE_TIME)
2479 t = mbedtls_time( NULL );
2480 *p++ = (unsigned char)( t >> 24 );
2481 *p++ = (unsigned char)( t >> 16 );
2482 *p++ = (unsigned char)( t >> 8 );
2483 *p++ = (unsigned char)( t );
2484
2485 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) );
2486 #else
2487 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 )
2488 return( ret );
2489
2490 p += 4;
2491 #endif /* MBEDTLS_HAVE_TIME */
2492
2493 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 )
2494 return( ret );
2495
2496 p += 28;
2497
2498 memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
2499
2500 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
2501
2502 /*
2503 * Resume is 0 by default, see ssl_handshake_init().
2504 * It may be already set to 1 by ssl_parse_session_ticket_ext().
2505 * If not, try looking up session ID in our cache.
2506 */
2507 if( ssl->handshake->resume == 0 &&
2508 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2509 ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
2510 #endif
2511 ssl->session_negotiate->id_len != 0 &&
2512 ssl->conf->f_get_cache != NULL &&
2513 ssl->conf->f_get_cache( ssl->conf->p_cache, ssl->session_negotiate ) == 0 )
2514 {
2515 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
2516 ssl->handshake->resume = 1;
2517 }
2518
2519 if( ssl->handshake->resume == 0 )
2520 {
2521 /*
2522 * New session, create a new session id,
2523 * unless we're about to issue a session ticket
2524 */
2525 ssl->state++;
2526
2527 #if defined(MBEDTLS_HAVE_TIME)
2528 ssl->session_negotiate->start = mbedtls_time( NULL );
2529 #endif
2530
2531 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2532 if( ssl->handshake->new_session_ticket != 0 )
2533 {
2534 ssl->session_negotiate->id_len = n = 0;
2535 memset( ssl->session_negotiate->id, 0, 32 );
2536 }
2537 else
2538 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2539 {
2540 ssl->session_negotiate->id_len = n = 32;
2541 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id,
2542 n ) ) != 0 )
2543 return( ret );
2544 }
2545 }
2546 else
2547 {
2548 /*
2549 * Resuming a session
2550 */
2551 n = ssl->session_negotiate->id_len;
2552 ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
2553
2554 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
2555 {
2556 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
2557 return( ret );
2558 }
2559 }
2560
2561 /*
2562 * 38 . 38 session id length
2563 * 39 . 38+n session id
2564 * 39+n . 40+n chosen ciphersuite
2565 * 41+n . 41+n chosen compression alg.
2566 * 42+n . 43+n extensions length
2567 * 44+n . 43+n+m extensions
2568 */
2569 *p++ = (unsigned char) ssl->session_negotiate->id_len;
2570 memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
2571 p += ssl->session_negotiate->id_len;
2572
2573 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) );
2574 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
2575 MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
2576 ssl->handshake->resume ? "a" : "no" ) );
2577
2578 *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 );
2579 *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite );
2580 *p++ = (unsigned char)( ssl->session_negotiate->compression );
2581
2582 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s",
2583 mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
2584 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
2585 ssl->session_negotiate->compression ) );
2586
2587 /* Do not write the extensions if the protocol is SSLv3 */
2588 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2589 if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
2590 {
2591 #endif
2592
2593 /*
2594 * First write extensions, then the total length
2595 */
2596 ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
2597 ext_len += olen;
2598
2599 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2600 ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
2601 ext_len += olen;
2602 #endif
2603
2604 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2605 ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
2606 ext_len += olen;
2607 #endif
2608
2609 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2610 ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
2611 ext_len += olen;
2612 #endif
2613
2614 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2615 ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
2616 ext_len += olen;
2617 #endif
2618
2619 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2620 ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
2621 ext_len += olen;
2622 #endif
2623
2624 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2625 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2626 if ( mbedtls_ssl_ciphersuite_uses_ec(
2627 mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
2628 {
2629 ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
2630 ext_len += olen;
2631 }
2632 #endif
2633
2634 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2635 ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
2636 ext_len += olen;
2637 #endif
2638
2639 #if defined(MBEDTLS_SSL_ALPN)
2640 ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
2641 ext_len += olen;
2642 #endif
2643
2644 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %d", ext_len ) );
2645
2646 if( ext_len > 0 )
2647 {
2648 *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
2649 *p++ = (unsigned char)( ( ext_len ) & 0xFF );
2650 p += ext_len;
2651 }
2652
2653 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2654 }
2655 #endif
2656
2657 ssl->out_msglen = p - buf;
2658 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2659 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
2660
2661 ret = mbedtls_ssl_write_handshake_msg( ssl );
2662
2663 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2664
2665 return( ret );
2666 }
2667
2668 #if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) && \
2669 !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) && \
2670 !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) && \
2671 !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
2672 !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
2673 !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
ssl_write_certificate_request(mbedtls_ssl_context * ssl)2674 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
2675 {
2676 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
2677 ssl->transform_negotiate->ciphersuite_info;
2678
2679 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
2680
2681 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
2682 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
2683 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
2684 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
2685 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2686 {
2687 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
2688 ssl->state++;
2689 return( 0 );
2690 }
2691
2692 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
2693 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2694 }
2695 #else
ssl_write_certificate_request(mbedtls_ssl_context * ssl)2696 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
2697 {
2698 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
2699 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
2700 ssl->transform_negotiate->ciphersuite_info;
2701 size_t dn_size, total_dn_size; /* excluding length bytes */
2702 size_t ct_len, sa_len; /* including length bytes */
2703 unsigned char *buf, *p;
2704 const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2705 const mbedtls_x509_crt *crt;
2706 int authmode;
2707
2708 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
2709
2710 ssl->state++;
2711
2712 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
2713 if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
2714 authmode = ssl->handshake->sni_authmode;
2715 else
2716 #endif
2717 authmode = ssl->conf->authmode;
2718
2719 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
2720 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
2721 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
2722 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
2723 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ||
2724 authmode == MBEDTLS_SSL_VERIFY_NONE )
2725 {
2726 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
2727 return( 0 );
2728 }
2729
2730 /*
2731 * 0 . 0 handshake type
2732 * 1 . 3 handshake length
2733 * 4 . 4 cert type count
2734 * 5 .. m-1 cert types
2735 * m .. m+1 sig alg length (TLS 1.2 only)
2736 * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
2737 * n .. n+1 length of all DNs
2738 * n+2 .. n+3 length of DN 1
2739 * n+4 .. ... Distinguished Name #1
2740 * ... .. ... length of DN 2, etc.
2741 */
2742 buf = ssl->out_msg;
2743 p = buf + 4;
2744
2745 /*
2746 * Supported certificate types
2747 *
2748 * ClientCertificateType certificate_types<1..2^8-1>;
2749 * enum { (255) } ClientCertificateType;
2750 */
2751 ct_len = 0;
2752
2753 #if defined(MBEDTLS_RSA_C)
2754 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
2755 #endif
2756 #if defined(MBEDTLS_ECDSA_C)
2757 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
2758 #endif
2759
2760 p[0] = (unsigned char) ct_len++;
2761 p += ct_len;
2762
2763 sa_len = 0;
2764 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
2765 /*
2766 * Add signature_algorithms for verify (TLS 1.2)
2767 *
2768 * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
2769 *
2770 * struct {
2771 * HashAlgorithm hash;
2772 * SignatureAlgorithm signature;
2773 * } SignatureAndHashAlgorithm;
2774 *
2775 * enum { (255) } HashAlgorithm;
2776 * enum { (255) } SignatureAlgorithm;
2777 */
2778 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
2779 {
2780 const int *cur;
2781
2782 /*
2783 * Supported signature algorithms
2784 */
2785 for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ )
2786 {
2787 unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur );
2788
2789 if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) )
2790 continue;
2791
2792 #if defined(MBEDTLS_RSA_C)
2793 p[2 + sa_len++] = hash;
2794 p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA;
2795 #endif
2796 #if defined(MBEDTLS_ECDSA_C)
2797 p[2 + sa_len++] = hash;
2798 p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA;
2799 #endif
2800 }
2801
2802 p[0] = (unsigned char)( sa_len >> 8 );
2803 p[1] = (unsigned char)( sa_len );
2804 sa_len += 2;
2805 p += sa_len;
2806 }
2807 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
2808
2809 /*
2810 * DistinguishedName certificate_authorities<0..2^16-1>;
2811 * opaque DistinguishedName<1..2^16-1>;
2812 */
2813 p += 2;
2814
2815 total_dn_size = 0;
2816
2817 if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED )
2818 {
2819 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
2820 if( ssl->handshake->sni_ca_chain != NULL )
2821 crt = ssl->handshake->sni_ca_chain;
2822 else
2823 #endif
2824 crt = ssl->conf->ca_chain;
2825
2826 while( crt != NULL && crt->version != 0 )
2827 {
2828 dn_size = crt->subject_raw.len;
2829
2830 if( end < p ||
2831 (size_t)( end - p ) < dn_size ||
2832 (size_t)( end - p ) < 2 + dn_size )
2833 {
2834 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) );
2835 break;
2836 }
2837
2838 *p++ = (unsigned char)( dn_size >> 8 );
2839 *p++ = (unsigned char)( dn_size );
2840 memcpy( p, crt->subject_raw.p, dn_size );
2841 p += dn_size;
2842
2843 MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size );
2844
2845 total_dn_size += 2 + dn_size;
2846 crt = crt->next;
2847 }
2848 }
2849
2850 ssl->out_msglen = p - buf;
2851 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2852 ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
2853 ssl->out_msg[4 + ct_len + sa_len] = (unsigned char)( total_dn_size >> 8 );
2854 ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size );
2855
2856 ret = mbedtls_ssl_write_handshake_msg( ssl );
2857
2858 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
2859
2860 return( ret );
2861 }
2862 #endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
2863 !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
2864 !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
2865 !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
2866 !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
2867 !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
2868
2869 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
2870 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
ssl_get_ecdh_params_from_cert(mbedtls_ssl_context * ssl)2871 static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
2872 {
2873 int ret;
2874
2875 if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) )
2876 {
2877 MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
2878 return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
2879 }
2880
2881 if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx,
2882 mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ),
2883 MBEDTLS_ECDH_OURS ) ) != 0 )
2884 {
2885 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret );
2886 return( ret );
2887 }
2888
2889 return( 0 );
2890 }
2891 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
2892 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
2893
2894 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) && \
2895 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
ssl_resume_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)2896 static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
2897 size_t *signature_len )
2898 {
2899 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
2900 * signature length which will be added in ssl_write_server_key_exchange
2901 * after the call to ssl_prepare_server_key_exchange.
2902 * ssl_write_server_key_exchange also takes care of incrementing
2903 * ssl->out_msglen. */
2904 unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
2905 size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
2906 - sig_start );
2907 int ret = ssl->conf->f_async_resume( ssl,
2908 sig_start, signature_len, sig_max_len );
2909 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
2910 {
2911 ssl->handshake->async_in_progress = 0;
2912 mbedtls_ssl_set_async_operation_data( ssl, NULL );
2913 }
2914 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
2915 return( ret );
2916 }
2917 #endif /* defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) &&
2918 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
2919
2920 /* Prepare the ServerKeyExchange message, up to and including
2921 * calculating the signature if any, but excluding formatting the
2922 * signature and sending the message. */
ssl_prepare_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)2923 static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
2924 size_t *signature_len )
2925 {
2926 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
2927 ssl->transform_negotiate->ciphersuite_info;
2928 #if defined(MBEDTLS_KEY_EXCHANGE__SOME_PFS__ENABLED)
2929 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
2930 unsigned char *dig_signed = NULL;
2931 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
2932 #endif /* MBEDTLS_KEY_EXCHANGE__SOME_PFS__ENABLED */
2933
2934 (void) ciphersuite_info; /* unused in some configurations */
2935 #if !defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
2936 (void) signature_len;
2937 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
2938
2939 ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
2940
2941 /*
2942 *
2943 * Part 1: Provide key exchange parameters for chosen ciphersuite.
2944 *
2945 */
2946
2947 /*
2948 * - ECJPAKE key exchanges
2949 */
2950 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2951 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2952 {
2953 int ret;
2954 size_t len = 0;
2955
2956 ret = mbedtls_ecjpake_write_round_two(
2957 &ssl->handshake->ecjpake_ctx,
2958 ssl->out_msg + ssl->out_msglen,
2959 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
2960 ssl->conf->f_rng, ssl->conf->p_rng );
2961 if( ret != 0 )
2962 {
2963 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret );
2964 return( ret );
2965 }
2966
2967 ssl->out_msglen += len;
2968 }
2969 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2970
2971 /*
2972 * For (EC)DHE key exchanges with PSK, parameters are prefixed by support
2973 * identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
2974 * we use empty support identity hints here.
2975 **/
2976 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
2977 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
2978 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
2979 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
2980 {
2981 ssl->out_msg[ssl->out_msglen++] = 0x00;
2982 ssl->out_msg[ssl->out_msglen++] = 0x00;
2983 }
2984 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
2985 MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
2986
2987 /*
2988 * - DHE key exchanges
2989 */
2990 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__DHE_ENABLED)
2991 if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
2992 {
2993 int ret;
2994 size_t len = 0;
2995
2996 if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
2997 {
2998 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) );
2999 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
3000 }
3001
3002 /*
3003 * Ephemeral DH parameters:
3004 *
3005 * struct {
3006 * opaque dh_p<1..2^16-1>;
3007 * opaque dh_g<1..2^16-1>;
3008 * opaque dh_Ys<1..2^16-1>;
3009 * } ServerDHParams;
3010 */
3011 if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx,
3012 &ssl->conf->dhm_P,
3013 &ssl->conf->dhm_G ) ) != 0 )
3014 {
3015 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret );
3016 return( ret );
3017 }
3018
3019 if( ( ret = mbedtls_dhm_make_params(
3020 &ssl->handshake->dhm_ctx,
3021 (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
3022 ssl->out_msg + ssl->out_msglen, &len,
3023 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3024 {
3025 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret );
3026 return( ret );
3027 }
3028
3029 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
3030 dig_signed = ssl->out_msg + ssl->out_msglen;
3031 #endif
3032
3033 ssl->out_msglen += len;
3034
3035 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
3036 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
3037 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
3038 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
3039 }
3040 #endif /* MBEDTLS_KEY_EXCHANGE__SOME__DHE_ENABLED */
3041
3042 /*
3043 * - ECDHE key exchanges
3044 */
3045 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__ECDHE_ENABLED)
3046 if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) )
3047 {
3048 /*
3049 * Ephemeral ECDH parameters:
3050 *
3051 * struct {
3052 * ECParameters curve_params;
3053 * ECPoint public;
3054 * } ServerECDHParams;
3055 */
3056 const mbedtls_ecp_curve_info **curve = NULL;
3057 const mbedtls_ecp_group_id *gid;
3058 int ret;
3059 size_t len = 0;
3060
3061 /* Match our preference list against the offered curves */
3062 for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ )
3063 for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
3064 if( (*curve)->grp_id == *gid )
3065 goto curve_matching_done;
3066
3067 curve_matching_done:
3068 if( curve == NULL || *curve == NULL )
3069 {
3070 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
3071 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
3072 }
3073
3074 MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
3075
3076 if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
3077 (*curve)->grp_id ) ) != 0 )
3078 {
3079 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
3080 return( ret );
3081 }
3082
3083 if( ( ret = mbedtls_ecdh_make_params(
3084 &ssl->handshake->ecdh_ctx, &len,
3085 ssl->out_msg + ssl->out_msglen,
3086 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
3087 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3088 {
3089 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
3090 return( ret );
3091 }
3092
3093 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
3094 dig_signed = ssl->out_msg + ssl->out_msglen;
3095 #endif
3096
3097 ssl->out_msglen += len;
3098
3099 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3100 MBEDTLS_DEBUG_ECDH_Q );
3101 }
3102 #endif /* MBEDTLS_KEY_EXCHANGE__SOME__ECDHE_ENABLED */
3103
3104 /*
3105 *
3106 * Part 2: For key exchanges involving the server signing the
3107 * exchange parameters, compute and add the signature here.
3108 *
3109 */
3110 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
3111 if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
3112 {
3113 size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
3114 size_t hashlen = 0;
3115 unsigned char hash[MBEDTLS_MD_MAX_SIZE];
3116 int ret;
3117
3118 /*
3119 * 2.1: Choose hash algorithm:
3120 * A: For TLS 1.2, obey signature-hash-algorithm extension
3121 * to choose appropriate hash.
3122 * B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1
3123 * (RFC 4492, Sec. 5.4)
3124 * C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3)
3125 */
3126
3127 mbedtls_md_type_t md_alg;
3128
3129 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3130 mbedtls_pk_type_t sig_alg =
3131 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
3132 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3133 {
3134 /* A: For TLS 1.2, obey signature-hash-algorithm extension
3135 * (RFC 5246, Sec. 7.4.1.4.1). */
3136 if( sig_alg == MBEDTLS_PK_NONE ||
3137 ( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
3138 sig_alg ) ) == MBEDTLS_MD_NONE )
3139 {
3140 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3141 /* (... because we choose a cipher suite
3142 * only if there is a matching hash.) */
3143 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3144 }
3145 }
3146 else
3147 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3148 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3149 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3150 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
3151 {
3152 /* B: Default hash SHA1 */
3153 md_alg = MBEDTLS_MD_SHA1;
3154 }
3155 else
3156 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3157 MBEDTLS_SSL_PROTO_TLS1_1 */
3158 {
3159 /* C: MD5 + SHA1 */
3160 md_alg = MBEDTLS_MD_NONE;
3161 }
3162
3163 MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %d for signing", md_alg ) );
3164
3165 /*
3166 * 2.2: Compute the hash to be signed
3167 */
3168 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3169 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3170 if( md_alg == MBEDTLS_MD_NONE )
3171 {
3172 hashlen = 36;
3173 ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash,
3174 dig_signed,
3175 dig_signed_len );
3176 if( ret != 0 )
3177 return( ret );
3178 }
3179 else
3180 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3181 MBEDTLS_SSL_PROTO_TLS1_1 */
3182 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3183 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3184 if( md_alg != MBEDTLS_MD_NONE )
3185 {
3186 ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
3187 dig_signed,
3188 dig_signed_len,
3189 md_alg );
3190 if( ret != 0 )
3191 return( ret );
3192 }
3193 else
3194 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
3195 MBEDTLS_SSL_PROTO_TLS1_2 */
3196 {
3197 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3198 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3199 }
3200
3201 MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
3202
3203 /*
3204 * 2.3: Compute and add the signature
3205 */
3206 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3207 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3208 {
3209 /*
3210 * For TLS 1.2, we need to specify signature and hash algorithm
3211 * explicitly through a prefix to the signature.
3212 *
3213 * struct {
3214 * HashAlgorithm hash;
3215 * SignatureAlgorithm signature;
3216 * } SignatureAndHashAlgorithm;
3217 *
3218 * struct {
3219 * SignatureAndHashAlgorithm algorithm;
3220 * opaque signature<0..2^16-1>;
3221 * } DigitallySigned;
3222 *
3223 */
3224
3225 ssl->out_msg[ssl->out_msglen++] =
3226 mbedtls_ssl_hash_from_md_alg( md_alg );
3227 ssl->out_msg[ssl->out_msglen++] =
3228 mbedtls_ssl_sig_from_pk_alg( sig_alg );
3229 }
3230 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3231
3232 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3233 if( ssl->conf->f_async_sign_start != NULL )
3234 {
3235 ret = ssl->conf->f_async_sign_start( ssl,
3236 mbedtls_ssl_own_cert( ssl ),
3237 md_alg, hash, hashlen );
3238 switch( ret )
3239 {
3240 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3241 /* act as if f_async_sign was null */
3242 break;
3243 case 0:
3244 ssl->handshake->async_in_progress = 1;
3245 return( ssl_resume_server_key_exchange( ssl, signature_len ) );
3246 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3247 ssl->handshake->async_in_progress = 1;
3248 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3249 default:
3250 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret );
3251 return( ret );
3252 }
3253 }
3254 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3255
3256 if( mbedtls_ssl_own_key( ssl ) == NULL )
3257 {
3258 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) );
3259 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3260 }
3261
3262 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3263 * signature length which will be added in ssl_write_server_key_exchange
3264 * after the call to ssl_prepare_server_key_exchange.
3265 * ssl_write_server_key_exchange also takes care of incrementing
3266 * ssl->out_msglen. */
3267 if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ),
3268 md_alg, hash, hashlen,
3269 ssl->out_msg + ssl->out_msglen + 2,
3270 signature_len,
3271 ssl->conf->f_rng,
3272 ssl->conf->p_rng ) ) != 0 )
3273 {
3274 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret );
3275 return( ret );
3276 }
3277 }
3278 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
3279
3280 return( 0 );
3281 }
3282
3283 /* Prepare the ServerKeyExchange message and send it. For ciphersuites
3284 * that do not include a ServerKeyExchange message, do nothing. Either
3285 * way, if successful, move on to the next step in the SSL state
3286 * machine. */
ssl_write_server_key_exchange(mbedtls_ssl_context * ssl)3287 static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
3288 {
3289 int ret;
3290 size_t signature_len = 0;
3291 #if defined(MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED)
3292 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3293 ssl->transform_negotiate->ciphersuite_info;
3294 #endif /* MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED */
3295
3296 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
3297
3298 #if defined(MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED)
3299 /* Extract static ECDH parameters and abort if ServerKeyExchange
3300 * is not needed. */
3301 if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) )
3302 {
3303 /* For suites involving ECDH, extract DH parameters
3304 * from certificate at this point. */
3305 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__ECDH_ENABLED)
3306 if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) )
3307 {
3308 ssl_get_ecdh_params_from_cert( ssl );
3309 }
3310 #endif /* MBEDTLS_KEY_EXCHANGE__SOME__ECDH_ENABLED */
3311
3312 /* Key exchanges not involving ephemeral keys don't use
3313 * ServerKeyExchange, so end here. */
3314 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
3315 ssl->state++;
3316 return( 0 );
3317 }
3318 #endif /* MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED */
3319
3320 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) && \
3321 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3322 /* If we have already prepared the message and there is an ongoing
3323 * signature operation, resume signing. */
3324 if( ssl->handshake->async_in_progress != 0 )
3325 {
3326 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) );
3327 ret = ssl_resume_server_key_exchange( ssl, &signature_len );
3328 }
3329 else
3330 #endif /* defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) &&
3331 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3332 {
3333 /* ServerKeyExchange is needed. Prepare the message. */
3334 ret = ssl_prepare_server_key_exchange( ssl, &signature_len );
3335 }
3336
3337 if( ret != 0 )
3338 {
3339 /* If we're starting to write a new message, set ssl->out_msglen
3340 * to 0. But if we're resuming after an asynchronous message,
3341 * out_msglen is the amount of data written so far and mst be
3342 * preserved. */
3343 if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3344 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) );
3345 else
3346 ssl->out_msglen = 0;
3347 return( ret );
3348 }
3349
3350 /* If there is a signature, write its length.
3351 * ssl_prepare_server_key_exchange already wrote the signature
3352 * itself at its proper place in the output buffer. */
3353 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
3354 if( signature_len != 0 )
3355 {
3356 ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len >> 8 );
3357 ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len );
3358
3359 MBEDTLS_SSL_DEBUG_BUF( 3, "my signature",
3360 ssl->out_msg + ssl->out_msglen,
3361 signature_len );
3362
3363 /* Skip over the already-written signature */
3364 ssl->out_msglen += signature_len;
3365 }
3366 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
3367
3368 /* Add header and send. */
3369 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3370 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
3371
3372 ssl->state++;
3373
3374 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3375 {
3376 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3377 return( ret );
3378 }
3379
3380 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
3381 return( 0 );
3382 }
3383
ssl_write_server_hello_done(mbedtls_ssl_context * ssl)3384 static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
3385 {
3386 int ret;
3387
3388 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
3389
3390 ssl->out_msglen = 4;
3391 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3392 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
3393
3394 ssl->state++;
3395
3396 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3397 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
3398 mbedtls_ssl_send_flight_completed( ssl );
3399 #endif
3400
3401 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3402 {
3403 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3404 return( ret );
3405 }
3406
3407 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3408 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
3409 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
3410 {
3411 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
3412 return( ret );
3413 }
3414 #endif /* MBEDTLS_SSL_PROTO_DTLS */
3415
3416 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
3417
3418 return( 0 );
3419 }
3420
3421 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
3422 defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
ssl_parse_client_dh_public(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3423 static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p,
3424 const unsigned char *end )
3425 {
3426 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3427 size_t n;
3428
3429 /*
3430 * Receive G^Y mod P, premaster = (G^Y)^X mod P
3431 */
3432 if( *p + 2 > end )
3433 {
3434 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3435 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3436 }
3437
3438 n = ( (*p)[0] << 8 ) | (*p)[1];
3439 *p += 2;
3440
3441 if( *p + n > end )
3442 {
3443 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3444 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3445 }
3446
3447 if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 )
3448 {
3449 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret );
3450 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
3451 }
3452
3453 *p += n;
3454
3455 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
3456
3457 return( ret );
3458 }
3459 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
3460 MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3461
3462 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3463 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3464
3465 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
ssl_resume_decrypt_pms(mbedtls_ssl_context * ssl,unsigned char * peer_pms,size_t * peer_pmslen,size_t peer_pmssize)3466 static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl,
3467 unsigned char *peer_pms,
3468 size_t *peer_pmslen,
3469 size_t peer_pmssize )
3470 {
3471 int ret = ssl->conf->f_async_resume( ssl,
3472 peer_pms, peer_pmslen, peer_pmssize );
3473 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3474 {
3475 ssl->handshake->async_in_progress = 0;
3476 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3477 }
3478 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret );
3479 return( ret );
3480 }
3481 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3482
ssl_decrypt_encrypted_pms(mbedtls_ssl_context * ssl,const unsigned char * p,const unsigned char * end,unsigned char * peer_pms,size_t * peer_pmslen,size_t peer_pmssize)3483 static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl,
3484 const unsigned char *p,
3485 const unsigned char *end,
3486 unsigned char *peer_pms,
3487 size_t *peer_pmslen,
3488 size_t peer_pmssize )
3489 {
3490 int ret;
3491 mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl );
3492 mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk;
3493 size_t len = mbedtls_pk_get_len( public_key );
3494
3495 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3496 /* If we have already started decoding the message and there is an ongoing
3497 * decryption operation, resume signing. */
3498 if( ssl->handshake->async_in_progress != 0 )
3499 {
3500 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) );
3501 return( ssl_resume_decrypt_pms( ssl,
3502 peer_pms, peer_pmslen, peer_pmssize ) );
3503 }
3504 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3505
3506 /*
3507 * Prepare to decrypt the premaster using own private RSA key
3508 */
3509 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3510 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3511 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
3512 {
3513 if ( p + 2 > end ) {
3514 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3515 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3516 }
3517 if( *p++ != ( ( len >> 8 ) & 0xFF ) ||
3518 *p++ != ( ( len ) & 0xFF ) )
3519 {
3520 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3521 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3522 }
3523 }
3524 #endif
3525
3526 if( p + len != end )
3527 {
3528 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3529 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3530 }
3531
3532 /*
3533 * Decrypt the premaster secret
3534 */
3535 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3536 if( ssl->conf->f_async_decrypt_start != NULL )
3537 {
3538 ret = ssl->conf->f_async_decrypt_start( ssl,
3539 mbedtls_ssl_own_cert( ssl ),
3540 p, len );
3541 switch( ret )
3542 {
3543 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3544 /* act as if f_async_decrypt_start was null */
3545 break;
3546 case 0:
3547 ssl->handshake->async_in_progress = 1;
3548 return( ssl_resume_decrypt_pms( ssl,
3549 peer_pms,
3550 peer_pmslen,
3551 peer_pmssize ) );
3552 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3553 ssl->handshake->async_in_progress = 1;
3554 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3555 default:
3556 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret );
3557 return( ret );
3558 }
3559 }
3560 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3561
3562 if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) )
3563 {
3564 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
3565 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3566 }
3567
3568 ret = mbedtls_pk_decrypt( private_key, p, len,
3569 peer_pms, peer_pmslen, peer_pmssize,
3570 ssl->conf->f_rng, ssl->conf->p_rng );
3571 return( ret );
3572 }
3573
ssl_parse_encrypted_pms(mbedtls_ssl_context * ssl,const unsigned char * p,const unsigned char * end,size_t pms_offset)3574 static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
3575 const unsigned char *p,
3576 const unsigned char *end,
3577 size_t pms_offset )
3578 {
3579 int ret;
3580 unsigned char *pms = ssl->handshake->premaster + pms_offset;
3581 unsigned char ver[2];
3582 unsigned char fake_pms[48], peer_pms[48];
3583 unsigned char mask;
3584 size_t i, peer_pmslen;
3585 unsigned int diff;
3586
3587 /* In case of a failure in decryption, the decryption may write less than
3588 * 2 bytes of output, but we always read the first two bytes. It doesn't
3589 * matter in the end because diff will be nonzero in that case due to
3590 * peer_pmslen being less than 48, and we only care whether diff is 0.
3591 * But do initialize peer_pms for robustness anyway. This also makes
3592 * memory analyzers happy (don't access uninitialized memory, even
3593 * if it's an unsigned char). */
3594 peer_pms[0] = peer_pms[1] = ~0;
3595
3596 ret = ssl_decrypt_encrypted_pms( ssl, p, end,
3597 peer_pms,
3598 &peer_pmslen,
3599 sizeof( peer_pms ) );
3600
3601 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3602 if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3603 return( ret );
3604 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3605
3606 mbedtls_ssl_write_version( ssl->handshake->max_major_ver,
3607 ssl->handshake->max_minor_ver,
3608 ssl->conf->transport, ver );
3609
3610 /* Avoid data-dependent branches while checking for invalid
3611 * padding, to protect against timing-based Bleichenbacher-type
3612 * attacks. */
3613 diff = (unsigned int) ret;
3614 diff |= peer_pmslen ^ 48;
3615 diff |= peer_pms[0] ^ ver[0];
3616 diff |= peer_pms[1] ^ ver[1];
3617
3618 /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
3619 /* MSVC has a warning about unary minus on unsigned, but this is
3620 * well-defined and precisely what we want to do here */
3621 #if defined(_MSC_VER)
3622 #pragma warning( push )
3623 #pragma warning( disable : 4146 )
3624 #endif
3625 mask = - ( ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ) );
3626 #if defined(_MSC_VER)
3627 #pragma warning( pop )
3628 #endif
3629
3630 /*
3631 * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
3632 * must not cause the connection to end immediately; instead, send a
3633 * bad_record_mac later in the handshake.
3634 * To protect against timing-based variants of the attack, we must
3635 * not have any branch that depends on whether the decryption was
3636 * successful. In particular, always generate the fake premaster secret,
3637 * regardless of whether it will ultimately influence the output or not.
3638 */
3639 ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) );
3640 if( ret != 0 )
3641 {
3642 /* It's ok to abort on an RNG failure, since this does not reveal
3643 * anything about the RSA decryption. */
3644 return( ret );
3645 }
3646
3647 #if defined(MBEDTLS_SSL_DEBUG_ALL)
3648 if( diff != 0 )
3649 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3650 #endif
3651
3652 if( sizeof( ssl->handshake->premaster ) < pms_offset ||
3653 sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
3654 {
3655 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3656 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3657 }
3658 ssl->handshake->pmslen = 48;
3659
3660 /* Set pms to either the true or the fake PMS, without
3661 * data-dependent branches. */
3662 for( i = 0; i < ssl->handshake->pmslen; i++ )
3663 pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
3664
3665 return( 0 );
3666 }
3667 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
3668 MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
3669
3670 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
ssl_parse_client_psk_identity(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3671 static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p,
3672 const unsigned char *end )
3673 {
3674 int ret = 0;
3675 size_t n;
3676
3677 if( ssl->conf->f_psk == NULL &&
3678 ( ssl->conf->psk == NULL || ssl->conf->psk_identity == NULL ||
3679 ssl->conf->psk_identity_len == 0 || ssl->conf->psk_len == 0 ) )
3680 {
3681 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
3682 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3683 }
3684
3685 /*
3686 * Receive client pre-shared key identity name
3687 */
3688 if( end - *p < 2 )
3689 {
3690 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3691 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3692 }
3693
3694 n = ( (*p)[0] << 8 ) | (*p)[1];
3695 *p += 2;
3696
3697 if( n < 1 || n > 65535 || n > (size_t) ( end - *p ) )
3698 {
3699 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3700 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3701 }
3702
3703 if( ssl->conf->f_psk != NULL )
3704 {
3705 if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 )
3706 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
3707 }
3708 else
3709 {
3710 /* Identity is not a big secret since clients send it in the clear,
3711 * but treat it carefully anyway, just in case */
3712 if( n != ssl->conf->psk_identity_len ||
3713 mbedtls_ssl_safer_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
3714 {
3715 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
3716 }
3717 }
3718
3719 if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
3720 {
3721 MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
3722 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
3723 MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
3724 return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
3725 }
3726
3727 *p += n;
3728
3729 return( 0 );
3730 }
3731 #endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */
3732
ssl_parse_client_key_exchange(mbedtls_ssl_context * ssl)3733 static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
3734 {
3735 int ret;
3736 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
3737 unsigned char *p, *end;
3738
3739 ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
3740
3741 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
3742
3743 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
3744 ( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3745 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
3746 if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
3747 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) &&
3748 ( ssl->handshake->async_in_progress != 0 ) )
3749 {
3750 /* We've already read a record and there is an asynchronous
3751 * operation in progress to decrypt it. So skip reading the
3752 * record. */
3753 MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) );
3754 }
3755 else
3756 #endif
3757 if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
3758 {
3759 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
3760 return( ret );
3761 }
3762
3763 p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
3764 end = ssl->in_msg + ssl->in_hslen;
3765
3766 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
3767 {
3768 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3769 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3770 }
3771
3772 if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
3773 {
3774 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3775 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3776 }
3777
3778 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
3779 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
3780 {
3781 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
3782 {
3783 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
3784 return( ret );
3785 }
3786
3787 if( p != end )
3788 {
3789 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
3790 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3791 }
3792
3793 if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
3794 ssl->handshake->premaster,
3795 MBEDTLS_PREMASTER_SIZE,
3796 &ssl->handshake->pmslen,
3797 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3798 {
3799 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
3800 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
3801 }
3802
3803 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
3804 }
3805 else
3806 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
3807 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
3808 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
3809 defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
3810 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
3811 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
3812 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
3813 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
3814 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
3815 {
3816 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
3817 p, end - p) ) != 0 )
3818 {
3819 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
3820 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
3821 }
3822
3823 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3824 MBEDTLS_DEBUG_ECDH_QP );
3825
3826 if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
3827 &ssl->handshake->pmslen,
3828 ssl->handshake->premaster,
3829 MBEDTLS_MPI_MAX_SIZE,
3830 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3831 {
3832 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
3833 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
3834 }
3835
3836 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3837 MBEDTLS_DEBUG_ECDH_Z );
3838 }
3839 else
3840 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
3841 MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
3842 MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
3843 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
3844 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
3845 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
3846 {
3847 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3848 {
3849 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3850 return( ret );
3851 }
3852
3853 if( p != end )
3854 {
3855 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
3856 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3857 }
3858
3859 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3860 ciphersuite_info->key_exchange ) ) != 0 )
3861 {
3862 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3863 return( ret );
3864 }
3865 }
3866 else
3867 #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
3868 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3869 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
3870 {
3871 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3872 if ( ssl->handshake->async_in_progress != 0 )
3873 {
3874 /* There is an asynchronous operation in progress to
3875 * decrypt the encrypted premaster secret, so skip
3876 * directly to resuming this operation. */
3877 MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) );
3878 /* Update p to skip the PSK identity. ssl_parse_encrypted_pms
3879 * won't actually use it, but maintain p anyway for robustness. */
3880 p += ssl->conf->psk_identity_len + 2;
3881 }
3882 else
3883 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3884 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3885 {
3886 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3887 return( ret );
3888 }
3889
3890 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
3891 {
3892 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
3893 return( ret );
3894 }
3895
3896 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3897 ciphersuite_info->key_exchange ) ) != 0 )
3898 {
3899 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3900 return( ret );
3901 }
3902 }
3903 else
3904 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
3905 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
3906 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
3907 {
3908 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3909 {
3910 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3911 return( ret );
3912 }
3913 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
3914 {
3915 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
3916 return( ret );
3917 }
3918
3919 if( p != end )
3920 {
3921 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
3922 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3923 }
3924
3925 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3926 ciphersuite_info->key_exchange ) ) != 0 )
3927 {
3928 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3929 return( ret );
3930 }
3931 }
3932 else
3933 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3934 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
3935 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
3936 {
3937 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3938 {
3939 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3940 return( ret );
3941 }
3942
3943 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
3944 p, end - p ) ) != 0 )
3945 {
3946 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
3947 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
3948 }
3949
3950 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3951 MBEDTLS_DEBUG_ECDH_QP );
3952
3953 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3954 ciphersuite_info->key_exchange ) ) != 0 )
3955 {
3956 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3957 return( ret );
3958 }
3959 }
3960 else
3961 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
3962 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
3963 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
3964 {
3965 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 )
3966 {
3967 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
3968 return( ret );
3969 }
3970 }
3971 else
3972 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
3973 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3974 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
3975 {
3976 ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx,
3977 p, end - p );
3978 if( ret != 0 )
3979 {
3980 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
3981 return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
3982 }
3983
3984 ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
3985 ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
3986 ssl->conf->f_rng, ssl->conf->p_rng );
3987 if( ret != 0 )
3988 {
3989 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
3990 return( ret );
3991 }
3992 }
3993 else
3994 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
3995 {
3996 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3997 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3998 }
3999
4000 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
4001 {
4002 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
4003 return( ret );
4004 }
4005
4006 ssl->state++;
4007
4008 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
4009
4010 return( 0 );
4011 }
4012
4013 #if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) && \
4014 !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) && \
4015 !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) && \
4016 !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
4017 !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
4018 !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4019 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4020 {
4021 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4022 ssl->transform_negotiate->ciphersuite_info;
4023
4024 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4025
4026 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
4027 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
4028 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
4029 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
4030 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
4031 {
4032 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4033 ssl->state++;
4034 return( 0 );
4035 }
4036
4037 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4038 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4039 }
4040 #else
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4041 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4042 {
4043 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
4044 size_t i, sig_len;
4045 unsigned char hash[48];
4046 unsigned char *hash_start = hash;
4047 size_t hashlen;
4048 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4049 mbedtls_pk_type_t pk_alg;
4050 #endif
4051 mbedtls_md_type_t md_alg;
4052 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4053 ssl->transform_negotiate->ciphersuite_info;
4054
4055 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4056
4057 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
4058 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
4059 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
4060 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
4061 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ||
4062 ssl->session_negotiate->peer_cert == NULL )
4063 {
4064 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4065 ssl->state++;
4066 return( 0 );
4067 }
4068
4069 /* Read the message without adding it to the checksum */
4070 ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
4071 if( 0 != ret )
4072 {
4073 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
4074 return( ret );
4075 }
4076
4077 ssl->state++;
4078
4079 /* Process the message contents */
4080 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
4081 ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY )
4082 {
4083 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4084 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4085 }
4086
4087 i = mbedtls_ssl_hs_hdr_len( ssl );
4088
4089 /*
4090 * struct {
4091 * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
4092 * opaque signature<0..2^16-1>;
4093 * } DigitallySigned;
4094 */
4095 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
4096 defined(MBEDTLS_SSL_PROTO_TLS1_1)
4097 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 )
4098 {
4099 md_alg = MBEDTLS_MD_NONE;
4100 hashlen = 36;
4101
4102 /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
4103 if( mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk,
4104 MBEDTLS_PK_ECDSA ) )
4105 {
4106 hash_start += 16;
4107 hashlen -= 16;
4108 md_alg = MBEDTLS_MD_SHA1;
4109 }
4110 }
4111 else
4112 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 ||
4113 MBEDTLS_SSL_PROTO_TLS1_1 */
4114 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4115 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
4116 {
4117 if( i + 2 > ssl->in_hslen )
4118 {
4119 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4120 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4121 }
4122
4123 /*
4124 * Hash
4125 */
4126 md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] );
4127
4128 if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) )
4129 {
4130 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4131 " for verify message" ) );
4132 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4133 }
4134
4135 #if !defined(MBEDTLS_MD_SHA1)
4136 if( MBEDTLS_MD_SHA1 == md_alg )
4137 hash_start += 16;
4138 #endif
4139
4140 /* Info from md_alg will be used instead */
4141 hashlen = 0;
4142
4143 i++;
4144
4145 /*
4146 * Signature
4147 */
4148 if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) )
4149 == MBEDTLS_PK_NONE )
4150 {
4151 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4152 " for verify message" ) );
4153 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4154 }
4155
4156 /*
4157 * Check the certificate's key type matches the signature alg
4158 */
4159 if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) )
4160 {
4161 MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
4162 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4163 }
4164
4165 i++;
4166 }
4167 else
4168 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
4169 {
4170 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4171 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4172 }
4173
4174 if( i + 2 > ssl->in_hslen )
4175 {
4176 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4177 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4178 }
4179
4180 sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
4181 i += 2;
4182
4183 if( i + sig_len != ssl->in_hslen )
4184 {
4185 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4186 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4187 }
4188
4189 /* Calculate hash and verify signature */
4190 ssl->handshake->calc_verify( ssl, hash );
4191
4192 if( ( ret = mbedtls_pk_verify( &ssl->session_negotiate->peer_cert->pk,
4193 md_alg, hash_start, hashlen,
4194 ssl->in_msg + i, sig_len ) ) != 0 )
4195 {
4196 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
4197 return( ret );
4198 }
4199
4200 mbedtls_ssl_update_handshake_status( ssl );
4201
4202 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
4203
4204 return( ret );
4205 }
4206 #endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
4207 !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
4208 !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
4209 !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
4210 !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
4211 !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
4212
4213 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_new_session_ticket(mbedtls_ssl_context * ssl)4214 static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
4215 {
4216 int ret;
4217 size_t tlen;
4218 uint32_t lifetime;
4219
4220 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
4221
4222 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
4223 ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
4224
4225 /*
4226 * struct {
4227 * uint32 ticket_lifetime_hint;
4228 * opaque ticket<0..2^16-1>;
4229 * } NewSessionTicket;
4230 *
4231 * 4 . 7 ticket_lifetime_hint (0 = unspecified)
4232 * 8 . 9 ticket_len (n)
4233 * 10 . 9+n ticket content
4234 */
4235
4236 if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
4237 ssl->session_negotiate,
4238 ssl->out_msg + 10,
4239 ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
4240 &tlen, &lifetime ) ) != 0 )
4241 {
4242 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
4243 tlen = 0;
4244 }
4245
4246 ssl->out_msg[4] = ( lifetime >> 24 ) & 0xFF;
4247 ssl->out_msg[5] = ( lifetime >> 16 ) & 0xFF;
4248 ssl->out_msg[6] = ( lifetime >> 8 ) & 0xFF;
4249 ssl->out_msg[7] = ( lifetime ) & 0xFF;
4250
4251 ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF );
4252 ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF );
4253
4254 ssl->out_msglen = 10 + tlen;
4255
4256 /*
4257 * Morally equivalent to updating ssl->state, but NewSessionTicket and
4258 * ChangeCipherSpec share the same state.
4259 */
4260 ssl->handshake->new_session_ticket = 0;
4261
4262 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
4263 {
4264 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
4265 return( ret );
4266 }
4267
4268 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
4269
4270 return( 0 );
4271 }
4272 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
4273
4274 /*
4275 * SSL handshake -- server side -- single step
4276 */
mbedtls_ssl_handshake_server_step(mbedtls_ssl_context * ssl)4277 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
4278 {
4279 int ret = 0;
4280
4281 if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
4282 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4283
4284 MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
4285
4286 if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
4287 return( ret );
4288
4289 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4290 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
4291 ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
4292 {
4293 if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
4294 return( ret );
4295 }
4296 #endif /* MBEDTLS_SSL_PROTO_DTLS */
4297
4298 switch( ssl->state )
4299 {
4300 case MBEDTLS_SSL_HELLO_REQUEST:
4301 ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
4302 break;
4303
4304 /*
4305 * <== ClientHello
4306 */
4307 case MBEDTLS_SSL_CLIENT_HELLO:
4308 ret = ssl_parse_client_hello( ssl );
4309 break;
4310
4311 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4312 case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
4313 return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
4314 #endif
4315
4316 /*
4317 * ==> ServerHello
4318 * Certificate
4319 * ( ServerKeyExchange )
4320 * ( CertificateRequest )
4321 * ServerHelloDone
4322 */
4323 case MBEDTLS_SSL_SERVER_HELLO:
4324 ret = ssl_write_server_hello( ssl );
4325 break;
4326
4327 case MBEDTLS_SSL_SERVER_CERTIFICATE:
4328 ret = mbedtls_ssl_write_certificate( ssl );
4329 break;
4330
4331 case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
4332 ret = ssl_write_server_key_exchange( ssl );
4333 break;
4334
4335 case MBEDTLS_SSL_CERTIFICATE_REQUEST:
4336 ret = ssl_write_certificate_request( ssl );
4337 break;
4338
4339 case MBEDTLS_SSL_SERVER_HELLO_DONE:
4340 ret = ssl_write_server_hello_done( ssl );
4341 break;
4342
4343 /*
4344 * <== ( Certificate/Alert )
4345 * ClientKeyExchange
4346 * ( CertificateVerify )
4347 * ChangeCipherSpec
4348 * Finished
4349 */
4350 case MBEDTLS_SSL_CLIENT_CERTIFICATE:
4351 ret = mbedtls_ssl_parse_certificate( ssl );
4352 break;
4353
4354 case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
4355 ret = ssl_parse_client_key_exchange( ssl );
4356 break;
4357
4358 case MBEDTLS_SSL_CERTIFICATE_VERIFY:
4359 ret = ssl_parse_certificate_verify( ssl );
4360 break;
4361
4362 case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
4363 ret = mbedtls_ssl_parse_change_cipher_spec( ssl );
4364 break;
4365
4366 case MBEDTLS_SSL_CLIENT_FINISHED:
4367 ret = mbedtls_ssl_parse_finished( ssl );
4368 break;
4369
4370 /*
4371 * ==> ( NewSessionTicket )
4372 * ChangeCipherSpec
4373 * Finished
4374 */
4375 case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
4376 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
4377 if( ssl->handshake->new_session_ticket != 0 )
4378 ret = ssl_write_new_session_ticket( ssl );
4379 else
4380 #endif
4381 ret = mbedtls_ssl_write_change_cipher_spec( ssl );
4382 break;
4383
4384 case MBEDTLS_SSL_SERVER_FINISHED:
4385 ret = mbedtls_ssl_write_finished( ssl );
4386 break;
4387
4388 case MBEDTLS_SSL_FLUSH_BUFFERS:
4389 MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
4390 ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
4391 break;
4392
4393 case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
4394 mbedtls_ssl_handshake_wrapup( ssl );
4395 break;
4396
4397 default:
4398 MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
4399 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4400 }
4401
4402 return( ret );
4403 }
4404 #endif /* MBEDTLS_SSL_SRV_C */
4405