1 /*
2 * SSLv3/TLSv1 server-side functions
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19
20 #include "common.h"
21
22 #if defined(MBEDTLS_SSL_SRV_C)
23
24 #if defined(MBEDTLS_PLATFORM_C)
25 #include "mbedtls/platform.h"
26 #else
27 #include <stdlib.h>
28 #define mbedtls_calloc calloc
29 #define mbedtls_free free
30 #endif
31
32 #include "mbedtls/ssl.h"
33 #include "mbedtls/ssl_internal.h"
34 #include "mbedtls/debug.h"
35 #include "mbedtls/error.h"
36 #include "mbedtls/platform_util.h"
37
38 #include <string.h>
39
40 #if defined(MBEDTLS_ECP_C)
41 #include "mbedtls/ecp.h"
42 #endif
43
44 #if defined(MBEDTLS_HAVE_TIME)
45 #include "mbedtls/platform_time.h"
46 #endif
47
48 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context * ssl,const unsigned char * info,size_t ilen)49 int mbedtls_ssl_set_client_transport_id( mbedtls_ssl_context *ssl,
50 const unsigned char *info,
51 size_t ilen )
52 {
53 if( ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER )
54 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
55
56 mbedtls_free( ssl->cli_id );
57
58 if( ( ssl->cli_id = mbedtls_calloc( 1, ilen ) ) == NULL )
59 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
60
61 memcpy( ssl->cli_id, info, ilen );
62 ssl->cli_id_len = ilen;
63
64 return( 0 );
65 }
66
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)67 void mbedtls_ssl_conf_dtls_cookies( mbedtls_ssl_config *conf,
68 mbedtls_ssl_cookie_write_t *f_cookie_write,
69 mbedtls_ssl_cookie_check_t *f_cookie_check,
70 void *p_cookie )
71 {
72 conf->f_cookie_write = f_cookie_write;
73 conf->f_cookie_check = f_cookie_check;
74 conf->p_cookie = p_cookie;
75 }
76 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
77
78 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
ssl_parse_servername_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)79 static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
80 const unsigned char *buf,
81 size_t len )
82 {
83 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
84 size_t servername_list_size, hostname_len;
85 const unsigned char *p;
86
87 MBEDTLS_SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) );
88
89 if( len < 2 )
90 {
91 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
92 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
93 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
94 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
95 }
96 servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
97 if( servername_list_size + 2 != len )
98 {
99 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
100 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
101 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
102 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
103 }
104
105 p = buf + 2;
106 while( servername_list_size > 2 )
107 {
108 hostname_len = ( ( p[1] << 8 ) | p[2] );
109 if( hostname_len + 3 > servername_list_size )
110 {
111 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
112 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
113 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
114 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
115 }
116
117 if( p[0] == MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME )
118 {
119 ret = ssl->conf->f_sni( ssl->conf->p_sni,
120 ssl, p + 3, hostname_len );
121 if( ret != 0 )
122 {
123 MBEDTLS_SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret );
124 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
125 MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME );
126 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
127 }
128 return( 0 );
129 }
130
131 servername_list_size -= hostname_len + 3;
132 p += hostname_len + 3;
133 }
134
135 if( servername_list_size != 0 )
136 {
137 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
138 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
139 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
140 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
141 }
142
143 return( 0 );
144 }
145 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
146
147 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
ssl_conf_has_psk_or_cb(mbedtls_ssl_config const * conf)148 static int ssl_conf_has_psk_or_cb( mbedtls_ssl_config const *conf )
149 {
150 if( conf->f_psk != NULL )
151 return( 1 );
152
153 if( conf->psk_identity_len == 0 || conf->psk_identity == NULL )
154 return( 0 );
155
156 if( conf->psk != NULL && conf->psk_len != 0 )
157 return( 1 );
158
159 #if defined(MBEDTLS_USE_PSA_CRYPTO)
160 if( ! mbedtls_svc_key_id_is_null( conf->psk_opaque ) )
161 return( 1 );
162 #endif /* MBEDTLS_USE_PSA_CRYPTO */
163
164 return( 0 );
165 }
166
167 #if defined(MBEDTLS_USE_PSA_CRYPTO)
ssl_use_opaque_psk(mbedtls_ssl_context const * ssl)168 static int ssl_use_opaque_psk( mbedtls_ssl_context const *ssl )
169 {
170 if( ssl->conf->f_psk != NULL )
171 {
172 /* If we've used a callback to select the PSK,
173 * the static configuration is irrelevant. */
174
175 if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) )
176 return( 1 );
177
178 return( 0 );
179 }
180
181 if( ! mbedtls_svc_key_id_is_null( ssl->conf->psk_opaque ) )
182 return( 1 );
183
184 return( 0 );
185 }
186 #endif /* MBEDTLS_USE_PSA_CRYPTO */
187 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
188
ssl_parse_renegotiation_info(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)189 static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
190 const unsigned char *buf,
191 size_t len )
192 {
193 #if defined(MBEDTLS_SSL_RENEGOTIATION)
194 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
195 {
196 /* Check verify-data in constant-time. The length OTOH is no secret */
197 if( len != 1 + ssl->verify_data_len ||
198 buf[0] != ssl->verify_data_len ||
199 mbedtls_ssl_safer_memcmp( buf + 1, ssl->peer_verify_data,
200 ssl->verify_data_len ) != 0 )
201 {
202 MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
203 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
204 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
205 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
206 }
207 }
208 else
209 #endif /* MBEDTLS_SSL_RENEGOTIATION */
210 {
211 if( len != 1 || buf[0] != 0x0 )
212 {
213 MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
214 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
215 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
216 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
217 }
218
219 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
220 }
221
222 return( 0 );
223 }
224
225 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
226 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
227
228 /*
229 * Status of the implementation of signature-algorithms extension:
230 *
231 * Currently, we are only considering the signature-algorithm extension
232 * to pick a ciphersuite which allows us to send the ServerKeyExchange
233 * message with a signature-hash combination that the user allows.
234 *
235 * We do *not* check whether all certificates in our certificate
236 * chain are signed with an allowed signature-hash pair.
237 * This needs to be done at a later stage.
238 *
239 */
ssl_parse_signature_algorithms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)240 static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
241 const unsigned char *buf,
242 size_t len )
243 {
244 size_t sig_alg_list_size;
245
246 const unsigned char *p;
247 const unsigned char *end = buf + len;
248
249 mbedtls_md_type_t md_cur;
250 mbedtls_pk_type_t sig_cur;
251
252 if ( len < 2 ) {
253 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
254 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
255 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
256 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
257 }
258 sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
259 if( sig_alg_list_size + 2 != len ||
260 sig_alg_list_size % 2 != 0 )
261 {
262 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
263 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
264 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
265 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
266 }
267
268 /* Currently we only guarantee signing the ServerKeyExchange message according
269 * to the constraints specified in this extension (see above), so it suffices
270 * to remember only one suitable hash for each possible signature algorithm.
271 *
272 * This will change when we also consider certificate signatures,
273 * in which case we will need to remember the whole signature-hash
274 * pair list from the extension.
275 */
276
277 for( p = buf + 2; p < end; p += 2 )
278 {
279 /* Silently ignore unknown signature or hash algorithms. */
280
281 if( ( sig_cur = mbedtls_ssl_pk_alg_from_sig( p[1] ) ) == MBEDTLS_PK_NONE )
282 {
283 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext"
284 " unknown sig alg encoding %d", p[1] ) );
285 continue;
286 }
287
288 /* Check if we support the hash the user proposes */
289 md_cur = mbedtls_ssl_md_alg_from_hash( p[0] );
290 if( md_cur == MBEDTLS_MD_NONE )
291 {
292 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
293 " unknown hash alg encoding %d", p[0] ) );
294 continue;
295 }
296
297 if( mbedtls_ssl_check_sig_hash( ssl, md_cur ) == 0 )
298 {
299 mbedtls_ssl_sig_hash_set_add( &ssl->handshake->hash_algs, sig_cur, md_cur );
300 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
301 " match sig %u and hash %u",
302 (unsigned) sig_cur, (unsigned) md_cur ) );
303 }
304 else
305 {
306 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: "
307 "hash alg %u not supported", (unsigned) md_cur ) );
308 }
309 }
310
311 return( 0 );
312 }
313 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
314 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
315
316 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
317 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_supported_elliptic_curves(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)318 static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
319 const unsigned char *buf,
320 size_t len )
321 {
322 size_t list_size, our_size;
323 const unsigned char *p;
324 const mbedtls_ecp_curve_info *curve_info, **curves;
325
326 if ( len < 2 ) {
327 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
328 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
329 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
330 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
331 }
332 list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
333 if( list_size + 2 != len ||
334 list_size % 2 != 0 )
335 {
336 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
337 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
338 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
339 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
340 }
341
342 /* Should never happen unless client duplicates the extension */
343 if( ssl->handshake->curves != NULL )
344 {
345 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
346 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
347 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
348 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
349 }
350
351 /* Don't allow our peer to make us allocate too much memory,
352 * and leave room for a final 0 */
353 our_size = list_size / 2 + 1;
354 if( our_size > MBEDTLS_ECP_DP_MAX )
355 our_size = MBEDTLS_ECP_DP_MAX;
356
357 if( ( curves = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == NULL )
358 {
359 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
360 MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
361 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
362 }
363
364 ssl->handshake->curves = curves;
365
366 p = buf + 2;
367 while( list_size > 0 && our_size > 1 )
368 {
369 curve_info = mbedtls_ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] );
370
371 if( curve_info != NULL )
372 {
373 *curves++ = curve_info;
374 our_size--;
375 }
376
377 list_size -= 2;
378 p += 2;
379 }
380
381 return( 0 );
382 }
383
ssl_parse_supported_point_formats(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)384 static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl,
385 const unsigned char *buf,
386 size_t len )
387 {
388 size_t list_size;
389 const unsigned char *p;
390
391 if( len == 0 || (size_t)( buf[0] + 1 ) != len )
392 {
393 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
394 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
395 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
396 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
397 }
398 list_size = buf[0];
399
400 p = buf + 1;
401 while( list_size > 0 )
402 {
403 if( p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED ||
404 p[0] == MBEDTLS_ECP_PF_COMPRESSED )
405 {
406 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
407 ssl->handshake->ecdh_ctx.point_format = p[0];
408 #endif
409 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
410 ssl->handshake->ecjpake_ctx.point_format = p[0];
411 #endif
412 MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
413 return( 0 );
414 }
415
416 list_size--;
417 p++;
418 }
419
420 return( 0 );
421 }
422 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
423 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
424
425 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_ecjpake_kkpp(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)426 static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
427 const unsigned char *buf,
428 size_t len )
429 {
430 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
431
432 if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
433 {
434 MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip ecjpake kkpp extension" ) );
435 return( 0 );
436 }
437
438 if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx,
439 buf, len ) ) != 0 )
440 {
441 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
442 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
443 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
444 return( ret );
445 }
446
447 /* Only mark the extension as OK when we're sure it is */
448 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK;
449
450 return( 0 );
451 }
452 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
453
454 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_parse_max_fragment_length_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)455 static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
456 const unsigned char *buf,
457 size_t len )
458 {
459 if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID )
460 {
461 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
462 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
463 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
464 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
465 }
466
467 ssl->session_negotiate->mfl_code = buf[0];
468
469 return( 0 );
470 }
471 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
472
473 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_parse_cid_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)474 static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl,
475 const unsigned char *buf,
476 size_t len )
477 {
478 size_t peer_cid_len;
479
480 /* CID extension only makes sense in DTLS */
481 if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
482 {
483 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
484 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
485 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
486 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
487 }
488
489 /*
490 * Quoting draft-ietf-tls-dtls-connection-id-05
491 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
492 *
493 * struct {
494 * opaque cid<0..2^8-1>;
495 * } ConnectionId;
496 */
497
498 if( len < 1 )
499 {
500 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
501 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
502 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
503 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
504 }
505
506 peer_cid_len = *buf++;
507 len--;
508
509 if( len != peer_cid_len )
510 {
511 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
512 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
513 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
514 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
515 }
516
517 /* Ignore CID if the user has disabled its use. */
518 if( ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED )
519 {
520 /* Leave ssl->handshake->cid_in_use in its default
521 * value of MBEDTLS_SSL_CID_DISABLED. */
522 MBEDTLS_SSL_DEBUG_MSG( 3, ( "Client sent CID extension, but CID disabled" ) );
523 return( 0 );
524 }
525
526 if( peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX )
527 {
528 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
529 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
530 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
531 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
532 }
533
534 ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED;
535 ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len;
536 memcpy( ssl->handshake->peer_cid, buf, peer_cid_len );
537
538 MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use of CID extension negotiated" ) );
539 MBEDTLS_SSL_DEBUG_BUF( 3, "Client CID", buf, peer_cid_len );
540
541 return( 0 );
542 }
543 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
544
545 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_parse_truncated_hmac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)546 static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
547 const unsigned char *buf,
548 size_t len )
549 {
550 if( len != 0 )
551 {
552 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
553 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
554 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
555 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
556 }
557
558 ((void) buf);
559
560 if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED )
561 ssl->session_negotiate->trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED;
562
563 return( 0 );
564 }
565 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
566
567 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_parse_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)568 static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
569 const unsigned char *buf,
570 size_t len )
571 {
572 if( len != 0 )
573 {
574 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
575 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
576 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
577 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
578 }
579
580 ((void) buf);
581
582 if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED &&
583 ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
584 {
585 ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED;
586 }
587
588 return( 0 );
589 }
590 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
591
592 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_parse_extended_ms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)593 static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
594 const unsigned char *buf,
595 size_t len )
596 {
597 if( len != 0 )
598 {
599 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
600 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
601 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
602 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
603 }
604
605 ((void) buf);
606
607 if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED &&
608 ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
609 {
610 ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
611 }
612
613 return( 0 );
614 }
615 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
616
617 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_parse_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t len)618 static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
619 unsigned char *buf,
620 size_t len )
621 {
622 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
623 mbedtls_ssl_session session;
624
625 mbedtls_ssl_session_init( &session );
626
627 if( ssl->conf->f_ticket_parse == NULL ||
628 ssl->conf->f_ticket_write == NULL )
629 {
630 return( 0 );
631 }
632
633 /* Remember the client asked us to send a new ticket */
634 ssl->handshake->new_session_ticket = 1;
635
636 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %" MBEDTLS_PRINTF_SIZET, len ) );
637
638 if( len == 0 )
639 return( 0 );
640
641 #if defined(MBEDTLS_SSL_RENEGOTIATION)
642 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
643 {
644 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
645 return( 0 );
646 }
647 #endif /* MBEDTLS_SSL_RENEGOTIATION */
648
649 /*
650 * Failures are ok: just ignore the ticket and proceed.
651 */
652 if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session,
653 buf, len ) ) != 0 )
654 {
655 mbedtls_ssl_session_free( &session );
656
657 if( ret == MBEDTLS_ERR_SSL_INVALID_MAC )
658 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) );
659 else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED )
660 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) );
661 else
662 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
663
664 return( 0 );
665 }
666
667 /*
668 * Keep the session ID sent by the client, since we MUST send it back to
669 * inform them we're accepting the ticket (RFC 5077 section 3.4)
670 */
671 session.id_len = ssl->session_negotiate->id_len;
672 memcpy( &session.id, ssl->session_negotiate->id, session.id_len );
673
674 mbedtls_ssl_session_free( ssl->session_negotiate );
675 memcpy( ssl->session_negotiate, &session, sizeof( mbedtls_ssl_session ) );
676
677 /* Zeroize instead of free as we copied the content */
678 mbedtls_platform_zeroize( &session, sizeof( mbedtls_ssl_session ) );
679
680 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
681
682 ssl->handshake->resume = 1;
683
684 /* Don't send a new ticket after all, this one is OK */
685 ssl->handshake->new_session_ticket = 0;
686
687 return( 0 );
688 }
689 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
690
691 #if defined(MBEDTLS_SSL_ALPN)
ssl_parse_alpn_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)692 static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
693 const unsigned char *buf, size_t len )
694 {
695 size_t list_len, cur_len, ours_len;
696 const unsigned char *theirs, *start, *end;
697 const char **ours;
698
699 /* If ALPN not configured, just ignore the extension */
700 if( ssl->conf->alpn_list == NULL )
701 return( 0 );
702
703 /*
704 * opaque ProtocolName<1..2^8-1>;
705 *
706 * struct {
707 * ProtocolName protocol_name_list<2..2^16-1>
708 * } ProtocolNameList;
709 */
710
711 /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
712 if( len < 4 )
713 {
714 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
715 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
716 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
717 }
718
719 list_len = ( buf[0] << 8 ) | buf[1];
720 if( list_len != len - 2 )
721 {
722 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
723 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
724 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
725 }
726
727 /*
728 * Validate peer's list (lengths)
729 */
730 start = buf + 2;
731 end = buf + len;
732 for( theirs = start; theirs != end; theirs += cur_len )
733 {
734 cur_len = *theirs++;
735
736 /* Current identifier must fit in list */
737 if( cur_len > (size_t)( end - theirs ) )
738 {
739 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
740 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
741 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
742 }
743
744 /* Empty strings MUST NOT be included */
745 if( cur_len == 0 )
746 {
747 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
748 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
749 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
750 }
751 }
752
753 /*
754 * Use our order of preference
755 */
756 for( ours = ssl->conf->alpn_list; *ours != NULL; ours++ )
757 {
758 ours_len = strlen( *ours );
759 for( theirs = start; theirs != end; theirs += cur_len )
760 {
761 cur_len = *theirs++;
762
763 if( cur_len == ours_len &&
764 memcmp( theirs, *ours, cur_len ) == 0 )
765 {
766 ssl->alpn_chosen = *ours;
767 return( 0 );
768 }
769 }
770 }
771
772 /* If we get there, no match was found */
773 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
774 MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
775 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
776 }
777 #endif /* MBEDTLS_SSL_ALPN */
778
779 #if defined(MBEDTLS_SSL_DTLS_SRTP)
ssl_parse_use_srtp_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)780 static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
781 const unsigned char *buf,
782 size_t len )
783 {
784 mbedtls_ssl_srtp_profile client_protection = MBEDTLS_TLS_SRTP_UNSET;
785 size_t i,j;
786 size_t profile_length;
787 uint16_t mki_length;
788 /*! 2 bytes for profile length and 1 byte for mki len */
789 const size_t size_of_lengths = 3;
790
791 /* If use_srtp is not configured, just ignore the extension */
792 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
793 ( ssl->conf->dtls_srtp_profile_list == NULL ) ||
794 ( ssl->conf->dtls_srtp_profile_list_len == 0 ) )
795 {
796 return( 0 );
797 }
798
799 /* RFC5764 section 4.1.1
800 * uint8 SRTPProtectionProfile[2];
801 *
802 * struct {
803 * SRTPProtectionProfiles SRTPProtectionProfiles;
804 * opaque srtp_mki<0..255>;
805 * } UseSRTPData;
806
807 * SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>;
808 */
809
810 /*
811 * Min length is 5: at least one protection profile(2 bytes)
812 * and length(2 bytes) + srtp_mki length(1 byte)
813 * Check here that we have at least 2 bytes of protection profiles length
814 * and one of srtp_mki length
815 */
816 if( len < size_of_lengths )
817 {
818 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
819 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
820 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
821 }
822
823 ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_TLS_SRTP_UNSET;
824
825 /* first 2 bytes are protection profile length(in bytes) */
826 profile_length = ( buf[0] << 8 ) | buf[1];
827 buf += 2;
828
829 /* The profile length cannot be bigger than input buffer size - lengths fields */
830 if( profile_length > len - size_of_lengths ||
831 profile_length % 2 != 0 ) /* profiles are 2 bytes long, so the length must be even */
832 {
833 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
834 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
835 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
836 }
837 /*
838 * parse the extension list values are defined in
839 * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
840 */
841 for( j = 0; j < profile_length; j += 2 )
842 {
843 uint16_t protection_profile_value = buf[j] << 8 | buf[j + 1];
844 client_protection = mbedtls_ssl_check_srtp_profile_value( protection_profile_value );
845
846 if( client_protection != MBEDTLS_TLS_SRTP_UNSET )
847 {
848 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found srtp profile: %s",
849 mbedtls_ssl_get_srtp_profile_as_string(
850 client_protection ) ) );
851 }
852 else
853 {
854 continue;
855 }
856 /* check if suggested profile is in our list */
857 for( i = 0; i < ssl->conf->dtls_srtp_profile_list_len; i++)
858 {
859 if( client_protection == ssl->conf->dtls_srtp_profile_list[i] )
860 {
861 ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i];
862 MBEDTLS_SSL_DEBUG_MSG( 3, ( "selected srtp profile: %s",
863 mbedtls_ssl_get_srtp_profile_as_string(
864 client_protection ) ) );
865 break;
866 }
867 }
868 if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_TLS_SRTP_UNSET )
869 break;
870 }
871 buf += profile_length; /* buf points to the mki length */
872 mki_length = *buf;
873 buf++;
874
875 if( mki_length > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH ||
876 mki_length + profile_length + size_of_lengths != len )
877 {
878 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
879 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
880 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
881 }
882
883 /* Parse the mki only if present and mki is supported locally */
884 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED &&
885 mki_length > 0 )
886 {
887 ssl->dtls_srtp_info.mki_len = mki_length;
888
889 memcpy( ssl->dtls_srtp_info.mki_value, buf, mki_length );
890
891 MBEDTLS_SSL_DEBUG_BUF( 3, "using mki", ssl->dtls_srtp_info.mki_value,
892 ssl->dtls_srtp_info.mki_len );
893 }
894
895 return( 0 );
896 }
897 #endif /* MBEDTLS_SSL_DTLS_SRTP */
898
899 /*
900 * Auxiliary functions for ServerHello parsing and related actions
901 */
902
903 #if defined(MBEDTLS_X509_CRT_PARSE_C)
904 /*
905 * Return 0 if the given key uses one of the acceptable curves, -1 otherwise
906 */
907 #if defined(MBEDTLS_ECDSA_C)
ssl_check_key_curve(mbedtls_pk_context * pk,const mbedtls_ecp_curve_info ** curves)908 static int ssl_check_key_curve( mbedtls_pk_context *pk,
909 const mbedtls_ecp_curve_info **curves )
910 {
911 const mbedtls_ecp_curve_info **crv = curves;
912 mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id;
913
914 while( *crv != NULL )
915 {
916 if( (*crv)->grp_id == grp_id )
917 return( 0 );
918 crv++;
919 }
920
921 return( -1 );
922 }
923 #endif /* MBEDTLS_ECDSA_C */
924
925 /*
926 * Try picking a certificate for this ciphersuite,
927 * return 0 on success and -1 on failure.
928 */
ssl_pick_cert(mbedtls_ssl_context * ssl,const mbedtls_ssl_ciphersuite_t * ciphersuite_info)929 static int ssl_pick_cert( mbedtls_ssl_context *ssl,
930 const mbedtls_ssl_ciphersuite_t * ciphersuite_info )
931 {
932 mbedtls_ssl_key_cert *cur, *list, *fallback = NULL;
933 mbedtls_pk_type_t pk_alg =
934 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
935 uint32_t flags;
936
937 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
938 if( ssl->handshake->sni_key_cert != NULL )
939 list = ssl->handshake->sni_key_cert;
940 else
941 #endif
942 list = ssl->conf->key_cert;
943
944 if( pk_alg == MBEDTLS_PK_NONE )
945 return( 0 );
946
947 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) );
948
949 if( list == NULL )
950 {
951 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server has no certificate" ) );
952 return( -1 );
953 }
954
955 for( cur = list; cur != NULL; cur = cur->next )
956 {
957 flags = 0;
958 MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
959 cur->cert );
960
961 if( ! mbedtls_pk_can_do( &cur->cert->pk, pk_alg ) )
962 {
963 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) );
964 continue;
965 }
966
967 /*
968 * This avoids sending the client a cert it'll reject based on
969 * keyUsage or other extensions.
970 *
971 * It also allows the user to provision different certificates for
972 * different uses based on keyUsage, eg if they want to avoid signing
973 * and decrypting with the same RSA key.
974 */
975 if( mbedtls_ssl_check_cert_usage( cur->cert, ciphersuite_info,
976 MBEDTLS_SSL_IS_SERVER, &flags ) != 0 )
977 {
978 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
979 "(extended) key usage extension" ) );
980 continue;
981 }
982
983 #if defined(MBEDTLS_ECDSA_C)
984 if( pk_alg == MBEDTLS_PK_ECDSA &&
985 ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 0 )
986 {
987 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) );
988 continue;
989 }
990 #endif
991
992 /*
993 * Try to select a SHA-1 certificate for pre-1.2 clients, but still
994 * present them a SHA-higher cert rather than failing if it's the only
995 * one we got that satisfies the other conditions.
996 */
997 if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 &&
998 cur->cert->sig_md != MBEDTLS_MD_SHA1 )
999 {
1000 if( fallback == NULL )
1001 fallback = cur;
1002 {
1003 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate not preferred: "
1004 "sha-2 with pre-TLS 1.2 client" ) );
1005 continue;
1006 }
1007 }
1008
1009 /* If we get there, we got a winner */
1010 break;
1011 }
1012
1013 if( cur == NULL )
1014 cur = fallback;
1015
1016 /* Do not update ssl->handshake->key_cert unless there is a match */
1017 if( cur != NULL )
1018 {
1019 ssl->handshake->key_cert = cur;
1020 MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
1021 ssl->handshake->key_cert->cert );
1022 return( 0 );
1023 }
1024
1025 return( -1 );
1026 }
1027 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1028
1029 /*
1030 * Check if a given ciphersuite is suitable for use with our config/keys/etc
1031 * Sets ciphersuite_info only if the suite matches.
1032 */
ssl_ciphersuite_match(mbedtls_ssl_context * ssl,int suite_id,const mbedtls_ssl_ciphersuite_t ** ciphersuite_info)1033 static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id,
1034 const mbedtls_ssl_ciphersuite_t **ciphersuite_info )
1035 {
1036 const mbedtls_ssl_ciphersuite_t *suite_info;
1037
1038 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1039 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1040 mbedtls_pk_type_t sig_type;
1041 #endif
1042
1043 suite_info = mbedtls_ssl_ciphersuite_from_id( suite_id );
1044 if( suite_info == NULL )
1045 {
1046 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
1047 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
1048 }
1049
1050 MBEDTLS_SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %#04x (%s)",
1051 (unsigned int) suite_id, suite_info->name ) );
1052
1053 if( suite_info->min_minor_ver > ssl->minor_ver ||
1054 suite_info->max_minor_ver < ssl->minor_ver )
1055 {
1056 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) );
1057 return( 0 );
1058 }
1059
1060 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1061 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
1062 ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
1063 return( 0 );
1064 #endif
1065
1066 #if defined(MBEDTLS_ARC4_C)
1067 if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED &&
1068 suite_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
1069 {
1070 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) );
1071 return( 0 );
1072 }
1073 #endif
1074
1075 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1076 if( suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
1077 ( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK ) == 0 )
1078 {
1079 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: ecjpake "
1080 "not configured or ext missing" ) );
1081 return( 0 );
1082 }
1083 #endif
1084
1085
1086 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
1087 if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) &&
1088 ( ssl->handshake->curves == NULL ||
1089 ssl->handshake->curves[0] == NULL ) )
1090 {
1091 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
1092 "no common elliptic curve" ) );
1093 return( 0 );
1094 }
1095 #endif
1096
1097 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
1098 /* If the ciphersuite requires a pre-shared key and we don't
1099 * have one, skip it now rather than failing later */
1100 if( mbedtls_ssl_ciphersuite_uses_psk( suite_info ) &&
1101 ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
1102 {
1103 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) );
1104 return( 0 );
1105 }
1106 #endif
1107
1108 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1109 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1110 /* If the ciphersuite requires signing, check whether
1111 * a suitable hash algorithm is present. */
1112 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
1113 {
1114 sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
1115 if( sig_type != MBEDTLS_PK_NONE &&
1116 mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == MBEDTLS_MD_NONE )
1117 {
1118 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
1119 "for signature algorithm %u", (unsigned) sig_type ) );
1120 return( 0 );
1121 }
1122 }
1123
1124 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1125 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1126
1127 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1128 /*
1129 * Final check: if ciphersuite requires us to have a
1130 * certificate/key of a particular type:
1131 * - select the appropriate certificate if we have one, or
1132 * - try the next ciphersuite if we don't
1133 * This must be done last since we modify the key_cert list.
1134 */
1135 if( ssl_pick_cert( ssl, suite_info ) != 0 )
1136 {
1137 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
1138 "no suitable certificate" ) );
1139 return( 0 );
1140 }
1141 #endif
1142
1143 *ciphersuite_info = suite_info;
1144 return( 0 );
1145 }
1146
1147 #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
ssl_parse_client_hello_v2(mbedtls_ssl_context * ssl)1148 static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
1149 {
1150 int ret, got_common_suite;
1151 unsigned int i, j;
1152 size_t n;
1153 unsigned int ciph_len, sess_len, chal_len;
1154 unsigned char *buf, *p;
1155 const int *ciphersuites;
1156 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
1157
1158 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
1159
1160 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1161 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
1162 {
1163 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
1164 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1165 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1166 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1167 }
1168 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1169
1170 buf = ssl->in_hdr;
1171
1172 MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, 5 );
1173
1174 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
1175 buf[2] ) );
1176 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
1177 ( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
1178 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
1179 buf[3], buf[4] ) );
1180
1181 /*
1182 * SSLv2 Client Hello
1183 *
1184 * Record layer:
1185 * 0 . 1 message length
1186 *
1187 * SSL layer:
1188 * 2 . 2 message type
1189 * 3 . 4 protocol version
1190 */
1191 if( buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO ||
1192 buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3 )
1193 {
1194 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1195 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1196 }
1197
1198 n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
1199
1200 if( n < 17 || n > 512 )
1201 {
1202 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1203 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1204 }
1205
1206 ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3;
1207 ssl->minor_ver = ( buf[4] <= ssl->conf->max_minor_ver )
1208 ? buf[4] : ssl->conf->max_minor_ver;
1209
1210 if( ssl->minor_ver < ssl->conf->min_minor_ver )
1211 {
1212 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
1213 " [%d:%d] < [%d:%d]",
1214 ssl->major_ver, ssl->minor_ver,
1215 ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
1216
1217 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1218 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1219 return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
1220 }
1221
1222 ssl->handshake->max_major_ver = buf[3];
1223 ssl->handshake->max_minor_ver = buf[4];
1224
1225 if( ( ret = mbedtls_ssl_fetch_input( ssl, 2 + n ) ) != 0 )
1226 {
1227 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1228 return( ret );
1229 }
1230
1231 ssl->handshake->update_checksum( ssl, buf + 2, n );
1232
1233 buf = ssl->in_msg;
1234 n = ssl->in_left - 5;
1235
1236 /*
1237 * 0 . 1 ciphersuitelist length
1238 * 2 . 3 session id length
1239 * 4 . 5 challenge length
1240 * 6 . .. ciphersuitelist
1241 * .. . .. session id
1242 * .. . .. challenge
1243 */
1244 MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, n );
1245
1246 ciph_len = ( buf[0] << 8 ) | buf[1];
1247 sess_len = ( buf[2] << 8 ) | buf[3];
1248 chal_len = ( buf[4] << 8 ) | buf[5];
1249
1250 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciph_len: %u, sess_len: %u, chal_len: %u",
1251 ciph_len, sess_len, chal_len ) );
1252
1253 /*
1254 * Make sure each parameter length is valid
1255 */
1256 if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
1257 {
1258 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1259 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1260 }
1261
1262 if( sess_len > 32 )
1263 {
1264 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1265 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1266 }
1267
1268 if( chal_len < 8 || chal_len > 32 )
1269 {
1270 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1271 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1272 }
1273
1274 if( n != 6 + ciph_len + sess_len + chal_len )
1275 {
1276 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1277 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1278 }
1279
1280 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
1281 buf + 6, ciph_len );
1282 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id",
1283 buf + 6 + ciph_len, sess_len );
1284 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, challenge",
1285 buf + 6 + ciph_len + sess_len, chal_len );
1286
1287 p = buf + 6 + ciph_len;
1288 ssl->session_negotiate->id_len = sess_len;
1289 memset( ssl->session_negotiate->id, 0,
1290 sizeof( ssl->session_negotiate->id ) );
1291 memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len );
1292
1293 p += sess_len;
1294 memset( ssl->handshake->randbytes, 0, 64 );
1295 memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
1296
1297 /*
1298 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
1299 */
1300 for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
1301 {
1302 if( p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
1303 {
1304 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
1305 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1306 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1307 {
1308 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
1309 "during renegotiation" ) );
1310
1311 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1312 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1313 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1314 }
1315 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1316 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
1317 break;
1318 }
1319 }
1320
1321 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
1322 for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
1323 {
1324 if( p[0] == 0 &&
1325 p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
1326 p[2] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
1327 {
1328 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
1329
1330 if( ssl->minor_ver < ssl->conf->max_minor_ver )
1331 {
1332 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
1333
1334 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1335 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
1336
1337 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1338 }
1339
1340 break;
1341 }
1342 }
1343 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
1344
1345 got_common_suite = 0;
1346 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
1347 ciphersuite_info = NULL;
1348 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
1349 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
1350 for( i = 0; ciphersuites[i] != 0; i++ )
1351 #else
1352 for( i = 0; ciphersuites[i] != 0; i++ )
1353 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
1354 #endif
1355 {
1356 if( p[0] != 0 ||
1357 p[1] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
1358 p[2] != ( ( ciphersuites[i] ) & 0xFF ) )
1359 continue;
1360
1361 got_common_suite = 1;
1362
1363 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
1364 &ciphersuite_info ) ) != 0 )
1365 return( ret );
1366
1367 if( ciphersuite_info != NULL )
1368 goto have_ciphersuite_v2;
1369 }
1370
1371 if( got_common_suite )
1372 {
1373 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
1374 "but none of them usable" ) );
1375 return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
1376 }
1377 else
1378 {
1379 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
1380 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
1381 }
1382
1383 have_ciphersuite_v2:
1384 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
1385
1386 ssl->session_negotiate->ciphersuite = ciphersuites[i];
1387 ssl->handshake->ciphersuite_info = ciphersuite_info;
1388
1389 /*
1390 * SSLv2 Client Hello relevant renegotiation security checks
1391 */
1392 if( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
1393 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
1394 {
1395 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
1396 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1397 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1398 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1399 }
1400
1401 ssl->in_left = 0;
1402 ssl->state++;
1403
1404 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) );
1405
1406 return( 0 );
1407 }
1408 #endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
1409
1410 /* This function doesn't alert on errors that happen early during
1411 ClientHello parsing because they might indicate that the client is
1412 not talking SSL/TLS at all and would not understand our alert. */
ssl_parse_client_hello(mbedtls_ssl_context * ssl)1413 static int ssl_parse_client_hello( mbedtls_ssl_context *ssl )
1414 {
1415 int ret, got_common_suite;
1416 size_t i, j;
1417 size_t ciph_offset, comp_offset, ext_offset;
1418 size_t msg_len, ciph_len, sess_len, comp_len, ext_len;
1419 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1420 size_t cookie_offset, cookie_len;
1421 #endif
1422 unsigned char *buf, *p, *ext;
1423 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1424 int renegotiation_info_seen = 0;
1425 #endif
1426 int handshake_failure = 0;
1427 const int *ciphersuites;
1428 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
1429 int major, minor;
1430
1431 /* If there is no signature-algorithm extension present,
1432 * we need to fall back to the default values for allowed
1433 * signature-hash pairs. */
1434 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1435 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1436 int sig_hash_alg_ext_present = 0;
1437 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1438 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1439
1440 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
1441
1442 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1443 read_record_header:
1444 #endif
1445 /*
1446 * If renegotiating, then the input was read with mbedtls_ssl_read_record(),
1447 * otherwise read it ourselves manually in order to support SSLv2
1448 * ClientHello, which doesn't use the same record layer format.
1449 */
1450 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1451 if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
1452 #endif
1453 {
1454 if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
1455 {
1456 /* No alert on a read error. */
1457 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1458 return( ret );
1459 }
1460 }
1461
1462 buf = ssl->in_hdr;
1463
1464 #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
1465 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1466 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM )
1467 #endif
1468 if( ( buf[0] & 0x80 ) != 0 )
1469 return( ssl_parse_client_hello_v2( ssl ) );
1470 #endif
1471
1472 MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_in_hdr_len( ssl ) );
1473
1474 /*
1475 * SSLv3/TLS Client Hello
1476 *
1477 * Record layer:
1478 * 0 . 0 message type
1479 * 1 . 2 protocol version
1480 * 3 . 11 DTLS: epoch + record sequence number
1481 * 3 . 4 message length
1482 */
1483 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d",
1484 buf[0] ) );
1485
1486 if( buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE )
1487 {
1488 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1489 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1490 }
1491
1492 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d",
1493 ( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) );
1494
1495 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, protocol version: [%d:%d]",
1496 buf[1], buf[2] ) );
1497
1498 mbedtls_ssl_read_version( &major, &minor, ssl->conf->transport, buf + 1 );
1499
1500 /* According to RFC 5246 Appendix E.1, the version here is typically
1501 * "{03,00}, the lowest version number supported by the client, [or] the
1502 * value of ClientHello.client_version", so the only meaningful check here
1503 * is the major version shouldn't be less than 3 */
1504 if( major < MBEDTLS_SSL_MAJOR_VERSION_3 )
1505 {
1506 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1507 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1508 }
1509
1510 /* For DTLS if this is the initial handshake, remember the client sequence
1511 * number to use it in our next message (RFC 6347 4.2.1) */
1512 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1513 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM
1514 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1515 && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
1516 #endif
1517 )
1518 {
1519 /* Epoch should be 0 for initial handshakes */
1520 if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 )
1521 {
1522 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1523 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1524 }
1525
1526 memcpy( ssl->cur_out_ctr + 2, ssl->in_ctr + 2, 6 );
1527
1528 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1529 if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
1530 {
1531 MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record, discarding" ) );
1532 ssl->next_record_offset = 0;
1533 ssl->in_left = 0;
1534 goto read_record_header;
1535 }
1536
1537 /* No MAC to check yet, so we can update right now */
1538 mbedtls_ssl_dtls_replay_update( ssl );
1539 #endif
1540 }
1541 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1542
1543 msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1];
1544
1545 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1546 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
1547 {
1548 /* Set by mbedtls_ssl_read_record() */
1549 msg_len = ssl->in_hslen;
1550 }
1551 else
1552 #endif
1553 {
1554 if( msg_len > MBEDTLS_SSL_IN_CONTENT_LEN )
1555 {
1556 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1557 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1558 }
1559
1560 if( ( ret = mbedtls_ssl_fetch_input( ssl,
1561 mbedtls_ssl_in_hdr_len( ssl ) + msg_len ) ) != 0 )
1562 {
1563 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1564 return( ret );
1565 }
1566
1567 /* Done reading this record, get ready for the next one */
1568 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1569 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1570 ssl->next_record_offset = msg_len + mbedtls_ssl_in_hdr_len( ssl );
1571 else
1572 #endif
1573 ssl->in_left = 0;
1574 }
1575
1576 buf = ssl->in_msg;
1577
1578 MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, msg_len );
1579
1580 ssl->handshake->update_checksum( ssl, buf, msg_len );
1581
1582 /*
1583 * Handshake layer:
1584 * 0 . 0 handshake type
1585 * 1 . 3 handshake length
1586 * 4 . 5 DTLS only: message seqence number
1587 * 6 . 8 DTLS only: fragment offset
1588 * 9 . 11 DTLS only: fragment length
1589 */
1590 if( msg_len < mbedtls_ssl_hs_hdr_len( ssl ) )
1591 {
1592 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1593 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1594 }
1595
1596 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
1597
1598 if( buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO )
1599 {
1600 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1601 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1602 }
1603
1604 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
1605 ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
1606
1607 /* We don't support fragmentation of ClientHello (yet?) */
1608 if( buf[1] != 0 ||
1609 msg_len != mbedtls_ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) )
1610 {
1611 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1612 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1613 }
1614
1615 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1616 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1617 {
1618 /*
1619 * Copy the client's handshake message_seq on initial handshakes,
1620 * check sequence number on renego.
1621 */
1622 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1623 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1624 {
1625 /* This couldn't be done in ssl_prepare_handshake_record() */
1626 unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
1627 ssl->in_msg[5];
1628
1629 if( cli_msg_seq != ssl->handshake->in_msg_seq )
1630 {
1631 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message_seq: "
1632 "%u (expected %u)", cli_msg_seq,
1633 ssl->handshake->in_msg_seq ) );
1634 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1635 }
1636
1637 ssl->handshake->in_msg_seq++;
1638 }
1639 else
1640 #endif
1641 {
1642 unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
1643 ssl->in_msg[5];
1644 ssl->handshake->out_msg_seq = cli_msg_seq;
1645 ssl->handshake->in_msg_seq = cli_msg_seq + 1;
1646 }
1647
1648 /*
1649 * For now we don't support fragmentation, so make sure
1650 * fragment_offset == 0 and fragment_length == length
1651 */
1652 if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
1653 memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
1654 {
1655 MBEDTLS_SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) );
1656 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
1657 }
1658 }
1659 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1660
1661 buf += mbedtls_ssl_hs_hdr_len( ssl );
1662 msg_len -= mbedtls_ssl_hs_hdr_len( ssl );
1663
1664 /*
1665 * ClientHello layer:
1666 * 0 . 1 protocol version
1667 * 2 . 33 random bytes (starting with 4 bytes of Unix time)
1668 * 34 . 35 session id length (1 byte)
1669 * 35 . 34+x session id
1670 * 35+x . 35+x DTLS only: cookie length (1 byte)
1671 * 36+x . .. DTLS only: cookie
1672 * .. . .. ciphersuite list length (2 bytes)
1673 * .. . .. ciphersuite list
1674 * .. . .. compression alg. list length (1 byte)
1675 * .. . .. compression alg. list
1676 * .. . .. extensions length (2 bytes, optional)
1677 * .. . .. extensions (optional)
1678 */
1679
1680 /*
1681 * Minimal length (with everything empty and extensions omitted) is
1682 * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
1683 * read at least up to session id length without worrying.
1684 */
1685 if( msg_len < 38 )
1686 {
1687 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1688 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1689 }
1690
1691 /*
1692 * Check and save the protocol version
1693 */
1694 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 );
1695
1696 mbedtls_ssl_read_version( &ssl->major_ver, &ssl->minor_ver,
1697 ssl->conf->transport, buf );
1698
1699 ssl->handshake->max_major_ver = ssl->major_ver;
1700 ssl->handshake->max_minor_ver = ssl->minor_ver;
1701
1702 if( ssl->major_ver < ssl->conf->min_major_ver ||
1703 ssl->minor_ver < ssl->conf->min_minor_ver )
1704 {
1705 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
1706 " [%d:%d] < [%d:%d]",
1707 ssl->major_ver, ssl->minor_ver,
1708 ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
1709 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1710 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1711 return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
1712 }
1713
1714 if( ssl->major_ver > ssl->conf->max_major_ver )
1715 {
1716 ssl->major_ver = ssl->conf->max_major_ver;
1717 ssl->minor_ver = ssl->conf->max_minor_ver;
1718 }
1719 else if( ssl->minor_ver > ssl->conf->max_minor_ver )
1720 ssl->minor_ver = ssl->conf->max_minor_ver;
1721
1722 /*
1723 * Save client random (inc. Unix time)
1724 */
1725 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 );
1726
1727 memcpy( ssl->handshake->randbytes, buf + 2, 32 );
1728
1729 /*
1730 * Check the session ID length and save session ID
1731 */
1732 sess_len = buf[34];
1733
1734 if( sess_len > sizeof( ssl->session_negotiate->id ) ||
1735 sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */
1736 {
1737 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1738 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1739 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1740 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1741 }
1742
1743 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len );
1744
1745 ssl->session_negotiate->id_len = sess_len;
1746 memset( ssl->session_negotiate->id, 0,
1747 sizeof( ssl->session_negotiate->id ) );
1748 memcpy( ssl->session_negotiate->id, buf + 35,
1749 ssl->session_negotiate->id_len );
1750
1751 /*
1752 * Check the cookie length and content
1753 */
1754 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1755 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1756 {
1757 cookie_offset = 35 + sess_len;
1758 cookie_len = buf[cookie_offset];
1759
1760 if( cookie_offset + 1 + cookie_len + 2 > msg_len )
1761 {
1762 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1763 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1764 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1765 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1766 }
1767
1768 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie",
1769 buf + cookie_offset + 1, cookie_len );
1770
1771 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
1772 if( ssl->conf->f_cookie_check != NULL
1773 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1774 && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
1775 #endif
1776 )
1777 {
1778 if( ssl->conf->f_cookie_check( ssl->conf->p_cookie,
1779 buf + cookie_offset + 1, cookie_len,
1780 ssl->cli_id, ssl->cli_id_len ) != 0 )
1781 {
1782 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification failed" ) );
1783 ssl->handshake->verify_cookie_len = 1;
1784 }
1785 else
1786 {
1787 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) );
1788 ssl->handshake->verify_cookie_len = 0;
1789 }
1790 }
1791 else
1792 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
1793 {
1794 /* We know we didn't send a cookie, so it should be empty */
1795 if( cookie_len != 0 )
1796 {
1797 /* This may be an attacker's probe, so don't send an alert */
1798 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1799 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1800 }
1801
1802 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification skipped" ) );
1803 }
1804
1805 /*
1806 * Check the ciphersuitelist length (will be parsed later)
1807 */
1808 ciph_offset = cookie_offset + 1 + cookie_len;
1809 }
1810 else
1811 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1812 ciph_offset = 35 + sess_len;
1813
1814 ciph_len = ( buf[ciph_offset + 0] << 8 )
1815 | ( buf[ciph_offset + 1] );
1816
1817 if( ciph_len < 2 ||
1818 ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
1819 ( ciph_len % 2 ) != 0 )
1820 {
1821 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1822 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1823 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1824 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1825 }
1826
1827 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
1828 buf + ciph_offset + 2, ciph_len );
1829
1830 /*
1831 * Check the compression algorithms length and pick one
1832 */
1833 comp_offset = ciph_offset + 2 + ciph_len;
1834
1835 comp_len = buf[comp_offset];
1836
1837 if( comp_len < 1 ||
1838 comp_len > 16 ||
1839 comp_len + comp_offset + 1 > msg_len )
1840 {
1841 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1842 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1843 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1844 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1845 }
1846
1847 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, compression",
1848 buf + comp_offset + 1, comp_len );
1849
1850 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
1851 #if defined(MBEDTLS_ZLIB_SUPPORT)
1852 for( i = 0; i < comp_len; ++i )
1853 {
1854 if( buf[comp_offset + 1 + i] == MBEDTLS_SSL_COMPRESS_DEFLATE )
1855 {
1856 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_DEFLATE;
1857 break;
1858 }
1859 }
1860 #endif
1861
1862 /* See comments in ssl_write_client_hello() */
1863 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1864 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1865 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
1866 #endif
1867
1868 /* Do not parse the extensions if the protocol is SSLv3 */
1869 #if defined(MBEDTLS_SSL_PROTO_SSL3)
1870 if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
1871 {
1872 #endif
1873 /*
1874 * Check the extension length
1875 */
1876 ext_offset = comp_offset + 1 + comp_len;
1877 if( msg_len > ext_offset )
1878 {
1879 if( msg_len < ext_offset + 2 )
1880 {
1881 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1882 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1883 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1884 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1885 }
1886
1887 ext_len = ( buf[ext_offset + 0] << 8 )
1888 | ( buf[ext_offset + 1] );
1889
1890 if( ( ext_len > 0 && ext_len < 4 ) ||
1891 msg_len != ext_offset + 2 + ext_len )
1892 {
1893 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1894 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1895 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1896 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1897 }
1898 }
1899 else
1900 ext_len = 0;
1901
1902 ext = buf + ext_offset + 2;
1903 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len );
1904
1905 while( ext_len != 0 )
1906 {
1907 unsigned int ext_id;
1908 unsigned int ext_size;
1909 if ( ext_len < 4 ) {
1910 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1911 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1912 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1913 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1914 }
1915 ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) );
1916 ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) );
1917
1918 if( ext_size + 4 > ext_len )
1919 {
1920 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1921 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1922 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1923 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1924 }
1925 switch( ext_id )
1926 {
1927 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
1928 case MBEDTLS_TLS_EXT_SERVERNAME:
1929 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
1930 if( ssl->conf->f_sni == NULL )
1931 break;
1932
1933 ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size );
1934 if( ret != 0 )
1935 return( ret );
1936 break;
1937 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
1938
1939 case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO:
1940 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
1941 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1942 renegotiation_info_seen = 1;
1943 #endif
1944
1945 ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
1946 if( ret != 0 )
1947 return( ret );
1948 break;
1949
1950 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1951 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1952 case MBEDTLS_TLS_EXT_SIG_ALG:
1953 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
1954
1955 ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
1956 if( ret != 0 )
1957 return( ret );
1958
1959 sig_hash_alg_ext_present = 1;
1960 break;
1961 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1962 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1963
1964 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
1965 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1966 case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
1967 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
1968
1969 ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
1970 if( ret != 0 )
1971 return( ret );
1972 break;
1973
1974 case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS:
1975 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) );
1976 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
1977
1978 ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size );
1979 if( ret != 0 )
1980 return( ret );
1981 break;
1982 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
1983 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1984
1985 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1986 case MBEDTLS_TLS_EXT_ECJPAKE_KKPP:
1987 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ecjpake kkpp extension" ) );
1988
1989 ret = ssl_parse_ecjpake_kkpp( ssl, ext + 4, ext_size );
1990 if( ret != 0 )
1991 return( ret );
1992 break;
1993 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1994
1995 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
1996 case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH:
1997 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
1998
1999 ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size );
2000 if( ret != 0 )
2001 return( ret );
2002 break;
2003 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2004
2005 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2006 case MBEDTLS_TLS_EXT_TRUNCATED_HMAC:
2007 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
2008
2009 ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size );
2010 if( ret != 0 )
2011 return( ret );
2012 break;
2013 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2014
2015 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2016 case MBEDTLS_TLS_EXT_CID:
2017 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found CID extension" ) );
2018
2019 ret = ssl_parse_cid_ext( ssl, ext + 4, ext_size );
2020 if( ret != 0 )
2021 return( ret );
2022 break;
2023 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2024
2025 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2026 case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
2027 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
2028
2029 ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
2030 if( ret != 0 )
2031 return( ret );
2032 break;
2033 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2034
2035 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2036 case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET:
2037 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
2038
2039 ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size );
2040 if( ret != 0 )
2041 return( ret );
2042 break;
2043 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2044
2045 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2046 case MBEDTLS_TLS_EXT_SESSION_TICKET:
2047 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) );
2048
2049 ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size );
2050 if( ret != 0 )
2051 return( ret );
2052 break;
2053 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2054
2055 #if defined(MBEDTLS_SSL_ALPN)
2056 case MBEDTLS_TLS_EXT_ALPN:
2057 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );
2058
2059 ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
2060 if( ret != 0 )
2061 return( ret );
2062 break;
2063 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2064
2065 #if defined(MBEDTLS_SSL_DTLS_SRTP)
2066 case MBEDTLS_TLS_EXT_USE_SRTP:
2067 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found use_srtp extension" ) );
2068
2069 ret = ssl_parse_use_srtp_ext( ssl, ext + 4, ext_size );
2070 if( ret != 0 )
2071 return( ret );
2072 break;
2073 #endif /* MBEDTLS_SSL_DTLS_SRTP */
2074
2075 default:
2076 MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %u (ignoring)",
2077 ext_id ) );
2078 }
2079
2080 ext_len -= 4 + ext_size;
2081 ext += 4 + ext_size;
2082
2083 if( ext_len > 0 && ext_len < 4 )
2084 {
2085 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
2086 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2087 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
2088 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2089 }
2090 }
2091 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2092 }
2093 #endif
2094
2095 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
2096 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
2097 {
2098 if( p[0] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
2099 p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
2100 {
2101 MBEDTLS_SSL_DEBUG_MSG( 2, ( "received FALLBACK_SCSV" ) );
2102
2103 if( ssl->minor_ver < ssl->conf->max_minor_ver )
2104 {
2105 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
2106
2107 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2108 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
2109
2110 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2111 }
2112
2113 break;
2114 }
2115 }
2116 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
2117
2118 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2119 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
2120
2121 /*
2122 * Try to fall back to default hash SHA1 if the client
2123 * hasn't provided any preferred signature-hash combinations.
2124 */
2125 if( sig_hash_alg_ext_present == 0 )
2126 {
2127 mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1;
2128
2129 if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 )
2130 md_default = MBEDTLS_MD_NONE;
2131
2132 mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default );
2133 }
2134
2135 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
2136 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
2137
2138 /*
2139 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
2140 */
2141 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
2142 {
2143 if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
2144 {
2145 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
2146 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2147 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
2148 {
2149 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
2150 "during renegotiation" ) );
2151 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2152 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2153 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2154 }
2155 #endif
2156 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
2157 break;
2158 }
2159 }
2160
2161 /*
2162 * Renegotiation security checks
2163 */
2164 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
2165 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
2166 {
2167 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
2168 handshake_failure = 1;
2169 }
2170 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2171 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2172 ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
2173 renegotiation_info_seen == 0 )
2174 {
2175 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
2176 handshake_failure = 1;
2177 }
2178 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2179 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
2180 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION )
2181 {
2182 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
2183 handshake_failure = 1;
2184 }
2185 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2186 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
2187 renegotiation_info_seen == 1 )
2188 {
2189 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
2190 handshake_failure = 1;
2191 }
2192 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2193
2194 if( handshake_failure == 1 )
2195 {
2196 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2197 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2198 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2199 }
2200
2201 /*
2202 * Search for a matching ciphersuite
2203 * (At the end because we need information from the EC-based extensions
2204 * and certificate from the SNI callback triggered by the SNI extension.)
2205 */
2206 got_common_suite = 0;
2207 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
2208 ciphersuite_info = NULL;
2209 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
2210 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
2211 for( i = 0; ciphersuites[i] != 0; i++ )
2212 #else
2213 for( i = 0; ciphersuites[i] != 0; i++ )
2214 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
2215 #endif
2216 {
2217 if( p[0] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
2218 p[1] != ( ( ciphersuites[i] ) & 0xFF ) )
2219 continue;
2220
2221 got_common_suite = 1;
2222
2223 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
2224 &ciphersuite_info ) ) != 0 )
2225 return( ret );
2226
2227 if( ciphersuite_info != NULL )
2228 goto have_ciphersuite;
2229 }
2230
2231 if( got_common_suite )
2232 {
2233 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
2234 "but none of them usable" ) );
2235 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2236 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2237 return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
2238 }
2239 else
2240 {
2241 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
2242 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2243 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2244 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
2245 }
2246
2247 have_ciphersuite:
2248 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
2249
2250 ssl->session_negotiate->ciphersuite = ciphersuites[i];
2251 ssl->handshake->ciphersuite_info = ciphersuite_info;
2252
2253 ssl->state++;
2254
2255 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2256 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
2257 mbedtls_ssl_recv_flight_completed( ssl );
2258 #endif
2259
2260 /* Debugging-only output for testsuite */
2261 #if defined(MBEDTLS_DEBUG_C) && \
2262 defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2263 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
2264 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
2265 {
2266 mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info );
2267 if( sig_alg != MBEDTLS_PK_NONE )
2268 {
2269 mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
2270 sig_alg );
2271 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
2272 mbedtls_ssl_hash_from_md_alg( md_alg ) ) );
2273 }
2274 else
2275 {
2276 MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm "
2277 "%u - should not happen", (unsigned) sig_alg ) );
2278 }
2279 }
2280 #endif
2281
2282 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
2283
2284 return( 0 );
2285 }
2286
2287 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_write_truncated_hmac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2288 static void ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl,
2289 unsigned char *buf,
2290 size_t *olen )
2291 {
2292 unsigned char *p = buf;
2293
2294 if( ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED )
2295 {
2296 *olen = 0;
2297 return;
2298 }
2299
2300 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) );
2301
2302 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
2303 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC ) & 0xFF );
2304
2305 *p++ = 0x00;
2306 *p++ = 0x00;
2307
2308 *olen = 4;
2309 }
2310 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2311
2312 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_write_cid_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2313 static void ssl_write_cid_ext( mbedtls_ssl_context *ssl,
2314 unsigned char *buf,
2315 size_t *olen )
2316 {
2317 unsigned char *p = buf;
2318 size_t ext_len;
2319 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2320
2321 *olen = 0;
2322
2323 /* Skip writing the extension if we don't want to use it or if
2324 * the client hasn't offered it. */
2325 if( ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED )
2326 return;
2327
2328 /* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX
2329 * which is at most 255, so the increment cannot overflow. */
2330 if( end < p || (size_t)( end - p ) < (unsigned)( ssl->own_cid_len + 5 ) )
2331 {
2332 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2333 return;
2334 }
2335
2336 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding CID extension" ) );
2337
2338 /*
2339 * Quoting draft-ietf-tls-dtls-connection-id-05
2340 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
2341 *
2342 * struct {
2343 * opaque cid<0..2^8-1>;
2344 * } ConnectionId;
2345 */
2346
2347 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_CID >> 8 ) & 0xFF );
2348 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_CID ) & 0xFF );
2349 ext_len = (size_t) ssl->own_cid_len + 1;
2350 *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
2351 *p++ = (unsigned char)( ( ext_len ) & 0xFF );
2352
2353 *p++ = (uint8_t) ssl->own_cid_len;
2354 memcpy( p, ssl->own_cid, ssl->own_cid_len );
2355
2356 *olen = ssl->own_cid_len + 5;
2357 }
2358 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
2359
2360 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2361 static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
2362 unsigned char *buf,
2363 size_t *olen )
2364 {
2365 unsigned char *p = buf;
2366 const mbedtls_ssl_ciphersuite_t *suite = NULL;
2367 const mbedtls_cipher_info_t *cipher = NULL;
2368
2369 if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ||
2370 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2371 {
2372 *olen = 0;
2373 return;
2374 }
2375
2376 /*
2377 * RFC 7366: "If a server receives an encrypt-then-MAC request extension
2378 * from a client and then selects a stream or Authenticated Encryption
2379 * with Associated Data (AEAD) ciphersuite, it MUST NOT send an
2380 * encrypt-then-MAC response extension back to the client."
2381 */
2382 if( ( suite = mbedtls_ssl_ciphersuite_from_id(
2383 ssl->session_negotiate->ciphersuite ) ) == NULL ||
2384 ( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL ||
2385 cipher->mode != MBEDTLS_MODE_CBC )
2386 {
2387 *olen = 0;
2388 return;
2389 }
2390
2391 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
2392
2393 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
2394 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
2395
2396 *p++ = 0x00;
2397 *p++ = 0x00;
2398
2399 *olen = 4;
2400 }
2401 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2402
2403 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2404 static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
2405 unsigned char *buf,
2406 size_t *olen )
2407 {
2408 unsigned char *p = buf;
2409
2410 if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED ||
2411 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2412 {
2413 *olen = 0;
2414 return;
2415 }
2416
2417 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
2418 "extension" ) );
2419
2420 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
2421 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF );
2422
2423 *p++ = 0x00;
2424 *p++ = 0x00;
2425
2426 *olen = 4;
2427 }
2428 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2429
2430 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2431 static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
2432 unsigned char *buf,
2433 size_t *olen )
2434 {
2435 unsigned char *p = buf;
2436
2437 if( ssl->handshake->new_session_ticket == 0 )
2438 {
2439 *olen = 0;
2440 return;
2441 }
2442
2443 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
2444
2445 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
2446 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET ) & 0xFF );
2447
2448 *p++ = 0x00;
2449 *p++ = 0x00;
2450
2451 *olen = 4;
2452 }
2453 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2454
ssl_write_renegotiation_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2455 static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
2456 unsigned char *buf,
2457 size_t *olen )
2458 {
2459 unsigned char *p = buf;
2460
2461 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION )
2462 {
2463 *olen = 0;
2464 return;
2465 }
2466
2467 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) );
2468
2469 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF );
2470 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ) & 0xFF );
2471
2472 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2473 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2474 {
2475 *p++ = 0x00;
2476 *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF;
2477 *p++ = ssl->verify_data_len * 2 & 0xFF;
2478
2479 memcpy( p, ssl->peer_verify_data, ssl->verify_data_len );
2480 p += ssl->verify_data_len;
2481 memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
2482 p += ssl->verify_data_len;
2483 }
2484 else
2485 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2486 {
2487 *p++ = 0x00;
2488 *p++ = 0x01;
2489 *p++ = 0x00;
2490 }
2491
2492 *olen = p - buf;
2493 }
2494
2495 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2496 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
2497 unsigned char *buf,
2498 size_t *olen )
2499 {
2500 unsigned char *p = buf;
2501
2502 if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE )
2503 {
2504 *olen = 0;
2505 return;
2506 }
2507
2508 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
2509
2510 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF );
2511 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF );
2512
2513 *p++ = 0x00;
2514 *p++ = 1;
2515
2516 *p++ = ssl->session_negotiate->mfl_code;
2517
2518 *olen = 5;
2519 }
2520 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2521
2522 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2523 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_supported_point_formats_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2524 static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
2525 unsigned char *buf,
2526 size_t *olen )
2527 {
2528 unsigned char *p = buf;
2529 ((void) ssl);
2530
2531 if( ( ssl->handshake->cli_exts &
2532 MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
2533 {
2534 *olen = 0;
2535 return;
2536 }
2537
2538 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
2539
2540 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
2541 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF );
2542
2543 *p++ = 0x00;
2544 *p++ = 2;
2545
2546 *p++ = 1;
2547 *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
2548
2549 *olen = 6;
2550 }
2551 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2552
2553 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2554 static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
2555 unsigned char *buf,
2556 size_t *olen )
2557 {
2558 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2559 unsigned char *p = buf;
2560 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2561 size_t kkpp_len;
2562
2563 *olen = 0;
2564
2565 /* Skip costly computation if not needed */
2566 if( ssl->handshake->ciphersuite_info->key_exchange !=
2567 MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2568 return;
2569
2570 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, ecjpake kkpp extension" ) );
2571
2572 if( end - p < 4 )
2573 {
2574 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2575 return;
2576 }
2577
2578 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP >> 8 ) & 0xFF );
2579 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ) & 0xFF );
2580
2581 ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
2582 p + 2, end - p - 2, &kkpp_len,
2583 ssl->conf->f_rng, ssl->conf->p_rng );
2584 if( ret != 0 )
2585 {
2586 MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
2587 return;
2588 }
2589
2590 *p++ = (unsigned char)( ( kkpp_len >> 8 ) & 0xFF );
2591 *p++ = (unsigned char)( ( kkpp_len ) & 0xFF );
2592
2593 *olen = kkpp_len + 4;
2594 }
2595 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2596
2597 #if defined(MBEDTLS_SSL_ALPN )
ssl_write_alpn_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2598 static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
2599 unsigned char *buf, size_t *olen )
2600 {
2601 if( ssl->alpn_chosen == NULL )
2602 {
2603 *olen = 0;
2604 return;
2605 }
2606
2607 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
2608
2609 /*
2610 * 0 . 1 ext identifier
2611 * 2 . 3 ext length
2612 * 4 . 5 protocol list length
2613 * 6 . 6 protocol name length
2614 * 7 . 7+n protocol name
2615 */
2616 buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF );
2617 buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN ) & 0xFF );
2618
2619 *olen = 7 + strlen( ssl->alpn_chosen );
2620
2621 buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
2622 buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF );
2623
2624 buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
2625 buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF );
2626
2627 buf[6] = (unsigned char)( ( ( *olen - 7 ) ) & 0xFF );
2628
2629 memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
2630 }
2631 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
2632
2633 #if defined(MBEDTLS_SSL_DTLS_SRTP ) && defined(MBEDTLS_SSL_PROTO_DTLS)
ssl_write_use_srtp_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2634 static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
2635 unsigned char *buf,
2636 size_t *olen )
2637 {
2638 size_t mki_len = 0, ext_len = 0;
2639 uint16_t profile_value = 0;
2640 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2641
2642 *olen = 0;
2643
2644 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
2645 ( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET ) )
2646 {
2647 return;
2648 }
2649
2650 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding use_srtp extension" ) );
2651
2652 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED )
2653 {
2654 mki_len = ssl->dtls_srtp_info.mki_len;
2655 }
2656
2657 /* The extension total size is 9 bytes :
2658 * - 2 bytes for the extension tag
2659 * - 2 bytes for the total size
2660 * - 2 bytes for the protection profile length
2661 * - 2 bytes for the protection profile
2662 * - 1 byte for the mki length
2663 * + the actual mki length
2664 * Check we have enough room in the output buffer */
2665 if( (size_t)( end - buf ) < mki_len + 9 )
2666 {
2667 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2668 return;
2669 }
2670
2671 /* extension */
2672 buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP >> 8 ) & 0xFF );
2673 buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP ) & 0xFF );
2674 /*
2675 * total length 5 and mki value: only one profile(2 bytes)
2676 * and length(2 bytes) and srtp_mki )
2677 */
2678 ext_len = 5 + mki_len;
2679 buf[2] = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
2680 buf[3] = (unsigned char)( ext_len & 0xFF );
2681
2682 /* protection profile length: 2 */
2683 buf[4] = 0x00;
2684 buf[5] = 0x02;
2685 profile_value = mbedtls_ssl_check_srtp_profile_value(
2686 ssl->dtls_srtp_info.chosen_dtls_srtp_profile );
2687 if( profile_value != MBEDTLS_TLS_SRTP_UNSET )
2688 {
2689 buf[6] = (unsigned char)( ( profile_value >> 8 ) & 0xFF );
2690 buf[7] = (unsigned char)( profile_value & 0xFF );
2691 }
2692 else
2693 {
2694 MBEDTLS_SSL_DEBUG_MSG( 1, ( "use_srtp extension invalid profile" ) );
2695 return;
2696 }
2697
2698 buf[8] = mki_len & 0xFF;
2699 memcpy( &buf[9], ssl->dtls_srtp_info.mki_value, mki_len );
2700
2701 *olen = 9 + mki_len;
2702 }
2703 #endif /* MBEDTLS_SSL_DTLS_SRTP */
2704
2705 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
ssl_write_hello_verify_request(mbedtls_ssl_context * ssl)2706 static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
2707 {
2708 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2709 unsigned char *p = ssl->out_msg + 4;
2710 unsigned char *cookie_len_byte;
2711
2712 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) );
2713
2714 /*
2715 * struct {
2716 * ProtocolVersion server_version;
2717 * opaque cookie<0..2^8-1>;
2718 * } HelloVerifyRequest;
2719 */
2720
2721 /* The RFC is not clear on this point, but sending the actual negotiated
2722 * version looks like the most interoperable thing to do. */
2723 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2724 ssl->conf->transport, p );
2725 MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 );
2726 p += 2;
2727
2728 /* If we get here, f_cookie_check is not null */
2729 if( ssl->conf->f_cookie_write == NULL )
2730 {
2731 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) );
2732 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2733 }
2734
2735 /* Skip length byte until we know the length */
2736 cookie_len_byte = p++;
2737
2738 if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
2739 &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
2740 ssl->cli_id, ssl->cli_id_len ) ) != 0 )
2741 {
2742 MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
2743 return( ret );
2744 }
2745
2746 *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) );
2747
2748 MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte );
2749
2750 ssl->out_msglen = p - ssl->out_msg;
2751 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2752 ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
2753
2754 ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
2755
2756 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
2757 {
2758 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
2759 return( ret );
2760 }
2761
2762 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2763 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2764 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
2765 {
2766 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
2767 return( ret );
2768 }
2769 #endif /* MBEDTLS_SSL_PROTO_DTLS */
2770
2771 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
2772
2773 return( 0 );
2774 }
2775 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2776
ssl_write_server_hello(mbedtls_ssl_context * ssl)2777 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
2778 {
2779 #if defined(MBEDTLS_HAVE_TIME)
2780 mbedtls_time_t t;
2781 #endif
2782 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2783 size_t olen, ext_len = 0, n;
2784 unsigned char *buf, *p;
2785
2786 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
2787
2788 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
2789 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2790 ssl->handshake->verify_cookie_len != 0 )
2791 {
2792 MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) );
2793 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2794
2795 return( ssl_write_hello_verify_request( ssl ) );
2796 }
2797 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2798
2799 if( ssl->conf->f_rng == NULL )
2800 {
2801 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
2802 return( MBEDTLS_ERR_SSL_NO_RNG );
2803 }
2804
2805 /*
2806 * 0 . 0 handshake type
2807 * 1 . 3 handshake length
2808 * 4 . 5 protocol version
2809 * 6 . 9 UNIX time()
2810 * 10 . 37 random bytes
2811 */
2812 buf = ssl->out_msg;
2813 p = buf + 4;
2814
2815 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2816 ssl->conf->transport, p );
2817 p += 2;
2818
2819 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
2820 buf[4], buf[5] ) );
2821
2822 #if defined(MBEDTLS_HAVE_TIME)
2823 t = mbedtls_time( NULL );
2824 *p++ = (unsigned char)( t >> 24 );
2825 *p++ = (unsigned char)( t >> 16 );
2826 *p++ = (unsigned char)( t >> 8 );
2827 *p++ = (unsigned char)( t );
2828
2829 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
2830 (long long) t ) );
2831 #else
2832 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 )
2833 return( ret );
2834
2835 p += 4;
2836 #endif /* MBEDTLS_HAVE_TIME */
2837
2838 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 )
2839 return( ret );
2840
2841 p += 28;
2842
2843 memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
2844
2845 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
2846
2847 /*
2848 * Resume is 0 by default, see ssl_handshake_init().
2849 * It may be already set to 1 by ssl_parse_session_ticket_ext().
2850 * If not, try looking up session ID in our cache.
2851 */
2852 if( ssl->handshake->resume == 0 &&
2853 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2854 ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
2855 #endif
2856 ssl->session_negotiate->id_len != 0 &&
2857 ssl->conf->f_get_cache != NULL &&
2858 ssl->conf->f_get_cache( ssl->conf->p_cache, ssl->session_negotiate ) == 0 )
2859 {
2860 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
2861 ssl->handshake->resume = 1;
2862 }
2863
2864 if( ssl->handshake->resume == 0 )
2865 {
2866 /*
2867 * New session, create a new session id,
2868 * unless we're about to issue a session ticket
2869 */
2870 ssl->state++;
2871
2872 #if defined(MBEDTLS_HAVE_TIME)
2873 ssl->session_negotiate->start = mbedtls_time( NULL );
2874 #endif
2875
2876 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2877 if( ssl->handshake->new_session_ticket != 0 )
2878 {
2879 ssl->session_negotiate->id_len = n = 0;
2880 memset( ssl->session_negotiate->id, 0, 32 );
2881 }
2882 else
2883 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2884 {
2885 ssl->session_negotiate->id_len = n = 32;
2886 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id,
2887 n ) ) != 0 )
2888 return( ret );
2889 }
2890 }
2891 else
2892 {
2893 /*
2894 * Resuming a session
2895 */
2896 n = ssl->session_negotiate->id_len;
2897 ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
2898
2899 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
2900 {
2901 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
2902 return( ret );
2903 }
2904 }
2905
2906 /*
2907 * 38 . 38 session id length
2908 * 39 . 38+n session id
2909 * 39+n . 40+n chosen ciphersuite
2910 * 41+n . 41+n chosen compression alg.
2911 * 42+n . 43+n extensions length
2912 * 44+n . 43+n+m extensions
2913 */
2914 *p++ = (unsigned char) ssl->session_negotiate->id_len;
2915 memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
2916 p += ssl->session_negotiate->id_len;
2917
2918 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n ) );
2919 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
2920 MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
2921 ssl->handshake->resume ? "a" : "no" ) );
2922
2923 *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 );
2924 *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite );
2925 *p++ = (unsigned char)( ssl->session_negotiate->compression );
2926
2927 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s",
2928 mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
2929 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
2930 (unsigned int) ssl->session_negotiate->compression ) );
2931
2932 /* Do not write the extensions if the protocol is SSLv3 */
2933 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2934 if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
2935 {
2936 #endif
2937
2938 /*
2939 * First write extensions, then the total length
2940 */
2941 ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
2942 ext_len += olen;
2943
2944 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2945 ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
2946 ext_len += olen;
2947 #endif
2948
2949 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2950 ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
2951 ext_len += olen;
2952 #endif
2953
2954 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2955 ssl_write_cid_ext( ssl, p + 2 + ext_len, &olen );
2956 ext_len += olen;
2957 #endif
2958
2959 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2960 ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
2961 ext_len += olen;
2962 #endif
2963
2964 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2965 ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
2966 ext_len += olen;
2967 #endif
2968
2969 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2970 ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
2971 ext_len += olen;
2972 #endif
2973
2974 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2975 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2976 if ( mbedtls_ssl_ciphersuite_uses_ec(
2977 mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
2978 {
2979 ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
2980 ext_len += olen;
2981 }
2982 #endif
2983
2984 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2985 ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
2986 ext_len += olen;
2987 #endif
2988
2989 #if defined(MBEDTLS_SSL_ALPN)
2990 ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
2991 ext_len += olen;
2992 #endif
2993
2994 #if defined(MBEDTLS_SSL_DTLS_SRTP)
2995 ssl_write_use_srtp_ext( ssl, p + 2 + ext_len, &olen );
2996 ext_len += olen;
2997 #endif
2998
2999 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %" MBEDTLS_PRINTF_SIZET,
3000 ext_len ) );
3001
3002 if( ext_len > 0 )
3003 {
3004 *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
3005 *p++ = (unsigned char)( ( ext_len ) & 0xFF );
3006 p += ext_len;
3007 }
3008
3009 #if defined(MBEDTLS_SSL_PROTO_SSL3)
3010 }
3011 #endif
3012
3013 ssl->out_msglen = p - buf;
3014 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3015 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
3016
3017 ret = mbedtls_ssl_write_handshake_msg( ssl );
3018
3019 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
3020
3021 return( ret );
3022 }
3023
3024 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_write_certificate_request(mbedtls_ssl_context * ssl)3025 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
3026 {
3027 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3028 ssl->handshake->ciphersuite_info;
3029
3030 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
3031
3032 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
3033 {
3034 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
3035 ssl->state++;
3036 return( 0 );
3037 }
3038
3039 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3040 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3041 }
3042 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_write_certificate_request(mbedtls_ssl_context * ssl)3043 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
3044 {
3045 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3046 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3047 ssl->handshake->ciphersuite_info;
3048 uint16_t dn_size, total_dn_size; /* excluding length bytes */
3049 size_t ct_len, sa_len; /* including length bytes */
3050 unsigned char *buf, *p;
3051 const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
3052 const mbedtls_x509_crt *crt;
3053 int authmode;
3054
3055 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
3056
3057 ssl->state++;
3058
3059 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
3060 if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
3061 authmode = ssl->handshake->sni_authmode;
3062 else
3063 #endif
3064 authmode = ssl->conf->authmode;
3065
3066 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ||
3067 authmode == MBEDTLS_SSL_VERIFY_NONE )
3068 {
3069 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
3070 return( 0 );
3071 }
3072
3073 /*
3074 * 0 . 0 handshake type
3075 * 1 . 3 handshake length
3076 * 4 . 4 cert type count
3077 * 5 .. m-1 cert types
3078 * m .. m+1 sig alg length (TLS 1.2 only)
3079 * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
3080 * n .. n+1 length of all DNs
3081 * n+2 .. n+3 length of DN 1
3082 * n+4 .. ... Distinguished Name #1
3083 * ... .. ... length of DN 2, etc.
3084 */
3085 buf = ssl->out_msg;
3086 p = buf + 4;
3087
3088 /*
3089 * Supported certificate types
3090 *
3091 * ClientCertificateType certificate_types<1..2^8-1>;
3092 * enum { (255) } ClientCertificateType;
3093 */
3094 ct_len = 0;
3095
3096 #if defined(MBEDTLS_RSA_C)
3097 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
3098 #endif
3099 #if defined(MBEDTLS_ECDSA_C)
3100 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
3101 #endif
3102
3103 p[0] = (unsigned char) ct_len++;
3104 p += ct_len;
3105
3106 sa_len = 0;
3107 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3108 /*
3109 * Add signature_algorithms for verify (TLS 1.2)
3110 *
3111 * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
3112 *
3113 * struct {
3114 * HashAlgorithm hash;
3115 * SignatureAlgorithm signature;
3116 * } SignatureAndHashAlgorithm;
3117 *
3118 * enum { (255) } HashAlgorithm;
3119 * enum { (255) } SignatureAlgorithm;
3120 */
3121 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3122 {
3123 const int *cur;
3124
3125 /*
3126 * Supported signature algorithms
3127 */
3128 for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ )
3129 {
3130 unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur );
3131
3132 if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) )
3133 continue;
3134
3135 #if defined(MBEDTLS_RSA_C)
3136 p[2 + sa_len++] = hash;
3137 p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA;
3138 #endif
3139 #if defined(MBEDTLS_ECDSA_C)
3140 p[2 + sa_len++] = hash;
3141 p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA;
3142 #endif
3143 }
3144
3145 p[0] = (unsigned char)( sa_len >> 8 );
3146 p[1] = (unsigned char)( sa_len );
3147 sa_len += 2;
3148 p += sa_len;
3149 }
3150 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3151
3152 /*
3153 * DistinguishedName certificate_authorities<0..2^16-1>;
3154 * opaque DistinguishedName<1..2^16-1>;
3155 */
3156 p += 2;
3157
3158 total_dn_size = 0;
3159
3160 if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED )
3161 {
3162 /* NOTE: If trusted certificates are provisioned
3163 * via a CA callback (configured through
3164 * `mbedtls_ssl_conf_ca_cb()`, then the
3165 * CertificateRequest is currently left empty. */
3166
3167 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
3168 if( ssl->handshake->sni_ca_chain != NULL )
3169 crt = ssl->handshake->sni_ca_chain;
3170 else
3171 #endif
3172 crt = ssl->conf->ca_chain;
3173
3174 while( crt != NULL && crt->version != 0 )
3175 {
3176 /* It follows from RFC 5280 A.1 that this length
3177 * can be represented in at most 11 bits. */
3178 dn_size = (uint16_t) crt->subject_raw.len;
3179
3180 if( end < p || (size_t)( end - p ) < 2 + (size_t) dn_size )
3181 {
3182 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) );
3183 break;
3184 }
3185
3186 *p++ = (unsigned char)( dn_size >> 8 );
3187 *p++ = (unsigned char)( dn_size );
3188 memcpy( p, crt->subject_raw.p, dn_size );
3189 p += dn_size;
3190
3191 MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size );
3192
3193 total_dn_size += 2 + dn_size;
3194 crt = crt->next;
3195 }
3196 }
3197
3198 ssl->out_msglen = p - buf;
3199 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3200 ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
3201 ssl->out_msg[4 + ct_len + sa_len] = (unsigned char)( total_dn_size >> 8 );
3202 ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size );
3203
3204 ret = mbedtls_ssl_write_handshake_msg( ssl );
3205
3206 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
3207
3208 return( ret );
3209 }
3210 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
3211
3212 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
3213 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
ssl_get_ecdh_params_from_cert(mbedtls_ssl_context * ssl)3214 static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
3215 {
3216 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3217
3218 if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) )
3219 {
3220 MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
3221 return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
3222 }
3223
3224 if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx,
3225 mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ),
3226 MBEDTLS_ECDH_OURS ) ) != 0 )
3227 {
3228 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret );
3229 return( ret );
3230 }
3231
3232 return( 0 );
3233 }
3234 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
3235 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
3236
3237 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3238 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
ssl_resume_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)3239 static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
3240 size_t *signature_len )
3241 {
3242 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3243 * signature length which will be added in ssl_write_server_key_exchange
3244 * after the call to ssl_prepare_server_key_exchange.
3245 * ssl_write_server_key_exchange also takes care of incrementing
3246 * ssl->out_msglen. */
3247 unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
3248 size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
3249 - sig_start );
3250 int ret = ssl->conf->f_async_resume( ssl,
3251 sig_start, signature_len, sig_max_len );
3252 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3253 {
3254 ssl->handshake->async_in_progress = 0;
3255 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3256 }
3257 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
3258 return( ret );
3259 }
3260 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3261 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3262
3263 /* Prepare the ServerKeyExchange message, up to and including
3264 * calculating the signature if any, but excluding formatting the
3265 * signature and sending the message. */
ssl_prepare_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)3266 static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
3267 size_t *signature_len )
3268 {
3269 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3270 ssl->handshake->ciphersuite_info;
3271
3272 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED)
3273 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3274 unsigned char *dig_signed = NULL;
3275 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3276 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */
3277
3278 (void) ciphersuite_info; /* unused in some configurations */
3279 #if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3280 (void) signature_len;
3281 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3282
3283 ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
3284
3285 /*
3286 *
3287 * Part 1: Provide key exchange parameters for chosen ciphersuite.
3288 *
3289 */
3290
3291 /*
3292 * - ECJPAKE key exchanges
3293 */
3294 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3295 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
3296 {
3297 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3298 size_t len = 0;
3299
3300 ret = mbedtls_ecjpake_write_round_two(
3301 &ssl->handshake->ecjpake_ctx,
3302 ssl->out_msg + ssl->out_msglen,
3303 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
3304 ssl->conf->f_rng, ssl->conf->p_rng );
3305 if( ret != 0 )
3306 {
3307 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret );
3308 return( ret );
3309 }
3310
3311 ssl->out_msglen += len;
3312 }
3313 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
3314
3315 /*
3316 * For (EC)DHE key exchanges with PSK, parameters are prefixed by support
3317 * identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
3318 * we use empty support identity hints here.
3319 **/
3320 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
3321 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
3322 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
3323 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
3324 {
3325 ssl->out_msg[ssl->out_msglen++] = 0x00;
3326 ssl->out_msg[ssl->out_msglen++] = 0x00;
3327 }
3328 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
3329 MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
3330
3331 /*
3332 * - DHE key exchanges
3333 */
3334 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED)
3335 if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
3336 {
3337 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3338 size_t len = 0;
3339
3340 if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
3341 {
3342 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) );
3343 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
3344 }
3345
3346 /*
3347 * Ephemeral DH parameters:
3348 *
3349 * struct {
3350 * opaque dh_p<1..2^16-1>;
3351 * opaque dh_g<1..2^16-1>;
3352 * opaque dh_Ys<1..2^16-1>;
3353 * } ServerDHParams;
3354 */
3355 if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx,
3356 &ssl->conf->dhm_P,
3357 &ssl->conf->dhm_G ) ) != 0 )
3358 {
3359 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret );
3360 return( ret );
3361 }
3362
3363 if( ( ret = mbedtls_dhm_make_params(
3364 &ssl->handshake->dhm_ctx,
3365 (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
3366 ssl->out_msg + ssl->out_msglen, &len,
3367 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3368 {
3369 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret );
3370 return( ret );
3371 }
3372
3373 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3374 dig_signed = ssl->out_msg + ssl->out_msglen;
3375 #endif
3376
3377 ssl->out_msglen += len;
3378
3379 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
3380 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
3381 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
3382 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
3383 }
3384 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */
3385
3386 /*
3387 * - ECDHE key exchanges
3388 */
3389 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED)
3390 if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) )
3391 {
3392 /*
3393 * Ephemeral ECDH parameters:
3394 *
3395 * struct {
3396 * ECParameters curve_params;
3397 * ECPoint public;
3398 * } ServerECDHParams;
3399 */
3400 const mbedtls_ecp_curve_info **curve = NULL;
3401 const mbedtls_ecp_group_id *gid;
3402 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3403 size_t len = 0;
3404
3405 /* Match our preference list against the offered curves */
3406 for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ )
3407 for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
3408 if( (*curve)->grp_id == *gid )
3409 goto curve_matching_done;
3410
3411 curve_matching_done:
3412 if( curve == NULL || *curve == NULL )
3413 {
3414 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
3415 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
3416 }
3417
3418 MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
3419
3420 if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
3421 (*curve)->grp_id ) ) != 0 )
3422 {
3423 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
3424 return( ret );
3425 }
3426
3427 if( ( ret = mbedtls_ecdh_make_params(
3428 &ssl->handshake->ecdh_ctx, &len,
3429 ssl->out_msg + ssl->out_msglen,
3430 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
3431 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3432 {
3433 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
3434 return( ret );
3435 }
3436
3437 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3438 dig_signed = ssl->out_msg + ssl->out_msglen;
3439 #endif
3440
3441 ssl->out_msglen += len;
3442
3443 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3444 MBEDTLS_DEBUG_ECDH_Q );
3445 }
3446 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */
3447
3448 /*
3449 *
3450 * Part 2: For key exchanges involving the server signing the
3451 * exchange parameters, compute and add the signature here.
3452 *
3453 */
3454 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3455 if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
3456 {
3457 size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
3458 size_t hashlen = 0;
3459 unsigned char hash[MBEDTLS_MD_MAX_SIZE];
3460 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3461
3462 /*
3463 * 2.1: Choose hash algorithm:
3464 * A: For TLS 1.2, obey signature-hash-algorithm extension
3465 * to choose appropriate hash.
3466 * B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1
3467 * (RFC 4492, Sec. 5.4)
3468 * C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3)
3469 */
3470
3471 mbedtls_md_type_t md_alg;
3472
3473 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3474 mbedtls_pk_type_t sig_alg =
3475 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
3476 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3477 {
3478 /* A: For TLS 1.2, obey signature-hash-algorithm extension
3479 * (RFC 5246, Sec. 7.4.1.4.1). */
3480 if( sig_alg == MBEDTLS_PK_NONE ||
3481 ( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
3482 sig_alg ) ) == MBEDTLS_MD_NONE )
3483 {
3484 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3485 /* (... because we choose a cipher suite
3486 * only if there is a matching hash.) */
3487 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3488 }
3489 }
3490 else
3491 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3492 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3493 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3494 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
3495 {
3496 /* B: Default hash SHA1 */
3497 md_alg = MBEDTLS_MD_SHA1;
3498 }
3499 else
3500 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3501 MBEDTLS_SSL_PROTO_TLS1_1 */
3502 {
3503 /* C: MD5 + SHA1 */
3504 md_alg = MBEDTLS_MD_NONE;
3505 }
3506
3507 MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %u for signing", (unsigned) md_alg ) );
3508
3509 /*
3510 * 2.2: Compute the hash to be signed
3511 */
3512 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3513 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3514 if( md_alg == MBEDTLS_MD_NONE )
3515 {
3516 hashlen = 36;
3517 ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash,
3518 dig_signed,
3519 dig_signed_len );
3520 if( ret != 0 )
3521 return( ret );
3522 }
3523 else
3524 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3525 MBEDTLS_SSL_PROTO_TLS1_1 */
3526 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3527 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3528 if( md_alg != MBEDTLS_MD_NONE )
3529 {
3530 ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
3531 dig_signed,
3532 dig_signed_len,
3533 md_alg );
3534 if( ret != 0 )
3535 return( ret );
3536 }
3537 else
3538 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
3539 MBEDTLS_SSL_PROTO_TLS1_2 */
3540 {
3541 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3542 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3543 }
3544
3545 MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
3546
3547 /*
3548 * 2.3: Compute and add the signature
3549 */
3550 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3551 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3552 {
3553 /*
3554 * For TLS 1.2, we need to specify signature and hash algorithm
3555 * explicitly through a prefix to the signature.
3556 *
3557 * struct {
3558 * HashAlgorithm hash;
3559 * SignatureAlgorithm signature;
3560 * } SignatureAndHashAlgorithm;
3561 *
3562 * struct {
3563 * SignatureAndHashAlgorithm algorithm;
3564 * opaque signature<0..2^16-1>;
3565 * } DigitallySigned;
3566 *
3567 */
3568
3569 ssl->out_msg[ssl->out_msglen++] =
3570 mbedtls_ssl_hash_from_md_alg( md_alg );
3571 ssl->out_msg[ssl->out_msglen++] =
3572 mbedtls_ssl_sig_from_pk_alg( sig_alg );
3573 }
3574 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3575
3576 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3577 if( ssl->conf->f_async_sign_start != NULL )
3578 {
3579 ret = ssl->conf->f_async_sign_start( ssl,
3580 mbedtls_ssl_own_cert( ssl ),
3581 md_alg, hash, hashlen );
3582 switch( ret )
3583 {
3584 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3585 /* act as if f_async_sign was null */
3586 break;
3587 case 0:
3588 ssl->handshake->async_in_progress = 1;
3589 return( ssl_resume_server_key_exchange( ssl, signature_len ) );
3590 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3591 ssl->handshake->async_in_progress = 1;
3592 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3593 default:
3594 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret );
3595 return( ret );
3596 }
3597 }
3598 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3599
3600 if( mbedtls_ssl_own_key( ssl ) == NULL )
3601 {
3602 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) );
3603 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3604 }
3605
3606 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3607 * signature length which will be added in ssl_write_server_key_exchange
3608 * after the call to ssl_prepare_server_key_exchange.
3609 * ssl_write_server_key_exchange also takes care of incrementing
3610 * ssl->out_msglen. */
3611 if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ),
3612 md_alg, hash, hashlen,
3613 ssl->out_msg + ssl->out_msglen + 2,
3614 signature_len,
3615 ssl->conf->f_rng,
3616 ssl->conf->p_rng ) ) != 0 )
3617 {
3618 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret );
3619 return( ret );
3620 }
3621 }
3622 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3623
3624 return( 0 );
3625 }
3626
3627 /* Prepare the ServerKeyExchange message and send it. For ciphersuites
3628 * that do not include a ServerKeyExchange message, do nothing. Either
3629 * way, if successful, move on to the next step in the SSL state
3630 * machine. */
ssl_write_server_key_exchange(mbedtls_ssl_context * ssl)3631 static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
3632 {
3633 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3634 size_t signature_len = 0;
3635 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3636 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3637 ssl->handshake->ciphersuite_info;
3638 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3639
3640 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
3641
3642 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3643 /* Extract static ECDH parameters and abort if ServerKeyExchange
3644 * is not needed. */
3645 if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) )
3646 {
3647 /* For suites involving ECDH, extract DH parameters
3648 * from certificate at this point. */
3649 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED)
3650 if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) )
3651 {
3652 ssl_get_ecdh_params_from_cert( ssl );
3653 }
3654 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */
3655
3656 /* Key exchanges not involving ephemeral keys don't use
3657 * ServerKeyExchange, so end here. */
3658 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
3659 ssl->state++;
3660 return( 0 );
3661 }
3662 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3663
3664 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3665 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3666 /* If we have already prepared the message and there is an ongoing
3667 * signature operation, resume signing. */
3668 if( ssl->handshake->async_in_progress != 0 )
3669 {
3670 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) );
3671 ret = ssl_resume_server_key_exchange( ssl, &signature_len );
3672 }
3673 else
3674 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3675 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3676 {
3677 /* ServerKeyExchange is needed. Prepare the message. */
3678 ret = ssl_prepare_server_key_exchange( ssl, &signature_len );
3679 }
3680
3681 if( ret != 0 )
3682 {
3683 /* If we're starting to write a new message, set ssl->out_msglen
3684 * to 0. But if we're resuming after an asynchronous message,
3685 * out_msglen is the amount of data written so far and mst be
3686 * preserved. */
3687 if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3688 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) );
3689 else
3690 ssl->out_msglen = 0;
3691 return( ret );
3692 }
3693
3694 /* If there is a signature, write its length.
3695 * ssl_prepare_server_key_exchange already wrote the signature
3696 * itself at its proper place in the output buffer. */
3697 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3698 if( signature_len != 0 )
3699 {
3700 ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len >> 8 );
3701 ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len );
3702
3703 MBEDTLS_SSL_DEBUG_BUF( 3, "my signature",
3704 ssl->out_msg + ssl->out_msglen,
3705 signature_len );
3706
3707 /* Skip over the already-written signature */
3708 ssl->out_msglen += signature_len;
3709 }
3710 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3711
3712 /* Add header and send. */
3713 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3714 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
3715
3716 ssl->state++;
3717
3718 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3719 {
3720 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3721 return( ret );
3722 }
3723
3724 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
3725 return( 0 );
3726 }
3727
ssl_write_server_hello_done(mbedtls_ssl_context * ssl)3728 static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
3729 {
3730 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3731
3732 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
3733
3734 ssl->out_msglen = 4;
3735 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3736 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
3737
3738 ssl->state++;
3739
3740 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3741 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
3742 mbedtls_ssl_send_flight_completed( ssl );
3743 #endif
3744
3745 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3746 {
3747 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3748 return( ret );
3749 }
3750
3751 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3752 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
3753 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
3754 {
3755 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
3756 return( ret );
3757 }
3758 #endif /* MBEDTLS_SSL_PROTO_DTLS */
3759
3760 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
3761
3762 return( 0 );
3763 }
3764
3765 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
3766 defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
ssl_parse_client_dh_public(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3767 static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p,
3768 const unsigned char *end )
3769 {
3770 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3771 size_t n;
3772
3773 /*
3774 * Receive G^Y mod P, premaster = (G^Y)^X mod P
3775 */
3776 if( *p + 2 > end )
3777 {
3778 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3779 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3780 }
3781
3782 n = ( (*p)[0] << 8 ) | (*p)[1];
3783 *p += 2;
3784
3785 if( *p + n > end )
3786 {
3787 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3788 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3789 }
3790
3791 if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 )
3792 {
3793 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret );
3794 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
3795 }
3796
3797 *p += n;
3798
3799 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
3800
3801 return( ret );
3802 }
3803 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
3804 MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3805
3806 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3807 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3808
3809 #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)3810 static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl,
3811 unsigned char *peer_pms,
3812 size_t *peer_pmslen,
3813 size_t peer_pmssize )
3814 {
3815 int ret = ssl->conf->f_async_resume( ssl,
3816 peer_pms, peer_pmslen, peer_pmssize );
3817 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3818 {
3819 ssl->handshake->async_in_progress = 0;
3820 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3821 }
3822 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret );
3823 return( ret );
3824 }
3825 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3826
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)3827 static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl,
3828 const unsigned char *p,
3829 const unsigned char *end,
3830 unsigned char *peer_pms,
3831 size_t *peer_pmslen,
3832 size_t peer_pmssize )
3833 {
3834 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3835 mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl );
3836 mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk;
3837 size_t len = mbedtls_pk_get_len( public_key );
3838
3839 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3840 /* If we have already started decoding the message and there is an ongoing
3841 * decryption operation, resume signing. */
3842 if( ssl->handshake->async_in_progress != 0 )
3843 {
3844 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) );
3845 return( ssl_resume_decrypt_pms( ssl,
3846 peer_pms, peer_pmslen, peer_pmssize ) );
3847 }
3848 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3849
3850 /*
3851 * Prepare to decrypt the premaster using own private RSA key
3852 */
3853 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3854 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3855 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
3856 {
3857 if ( p + 2 > end ) {
3858 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3859 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3860 }
3861 if( *p++ != ( ( len >> 8 ) & 0xFF ) ||
3862 *p++ != ( ( len ) & 0xFF ) )
3863 {
3864 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3865 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3866 }
3867 }
3868 #endif
3869
3870 if( p + len != end )
3871 {
3872 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3873 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3874 }
3875
3876 /*
3877 * Decrypt the premaster secret
3878 */
3879 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3880 if( ssl->conf->f_async_decrypt_start != NULL )
3881 {
3882 ret = ssl->conf->f_async_decrypt_start( ssl,
3883 mbedtls_ssl_own_cert( ssl ),
3884 p, len );
3885 switch( ret )
3886 {
3887 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3888 /* act as if f_async_decrypt_start was null */
3889 break;
3890 case 0:
3891 ssl->handshake->async_in_progress = 1;
3892 return( ssl_resume_decrypt_pms( ssl,
3893 peer_pms,
3894 peer_pmslen,
3895 peer_pmssize ) );
3896 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3897 ssl->handshake->async_in_progress = 1;
3898 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3899 default:
3900 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret );
3901 return( ret );
3902 }
3903 }
3904 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3905
3906 if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) )
3907 {
3908 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
3909 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3910 }
3911
3912 ret = mbedtls_pk_decrypt( private_key, p, len,
3913 peer_pms, peer_pmslen, peer_pmssize,
3914 ssl->conf->f_rng, ssl->conf->p_rng );
3915 return( ret );
3916 }
3917
ssl_parse_encrypted_pms(mbedtls_ssl_context * ssl,const unsigned char * p,const unsigned char * end,size_t pms_offset)3918 static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
3919 const unsigned char *p,
3920 const unsigned char *end,
3921 size_t pms_offset )
3922 {
3923 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3924 unsigned char *pms = ssl->handshake->premaster + pms_offset;
3925 unsigned char ver[2];
3926 unsigned char fake_pms[48], peer_pms[48];
3927 unsigned char mask;
3928 size_t i, peer_pmslen;
3929 unsigned int diff;
3930
3931 /* In case of a failure in decryption, the decryption may write less than
3932 * 2 bytes of output, but we always read the first two bytes. It doesn't
3933 * matter in the end because diff will be nonzero in that case due to
3934 * ret being nonzero, and we only care whether diff is 0.
3935 * But do initialize peer_pms and peer_pmslen for robustness anyway. This
3936 * also makes memory analyzers happy (don't access uninitialized memory,
3937 * even if it's an unsigned char). */
3938 peer_pms[0] = peer_pms[1] = ~0;
3939 peer_pmslen = 0;
3940
3941 ret = ssl_decrypt_encrypted_pms( ssl, p, end,
3942 peer_pms,
3943 &peer_pmslen,
3944 sizeof( peer_pms ) );
3945
3946 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3947 if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3948 return( ret );
3949 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3950
3951 mbedtls_ssl_write_version( ssl->handshake->max_major_ver,
3952 ssl->handshake->max_minor_ver,
3953 ssl->conf->transport, ver );
3954
3955 /* Avoid data-dependent branches while checking for invalid
3956 * padding, to protect against timing-based Bleichenbacher-type
3957 * attacks. */
3958 diff = (unsigned int) ret;
3959 diff |= peer_pmslen ^ 48;
3960 diff |= peer_pms[0] ^ ver[0];
3961 diff |= peer_pms[1] ^ ver[1];
3962
3963 /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
3964 /* MSVC has a warning about unary minus on unsigned, but this is
3965 * well-defined and precisely what we want to do here */
3966 #if defined(_MSC_VER)
3967 #pragma warning( push )
3968 #pragma warning( disable : 4146 )
3969 #endif
3970 mask = - ( ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ) );
3971 #if defined(_MSC_VER)
3972 #pragma warning( pop )
3973 #endif
3974
3975 /*
3976 * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
3977 * must not cause the connection to end immediately; instead, send a
3978 * bad_record_mac later in the handshake.
3979 * To protect against timing-based variants of the attack, we must
3980 * not have any branch that depends on whether the decryption was
3981 * successful. In particular, always generate the fake premaster secret,
3982 * regardless of whether it will ultimately influence the output or not.
3983 */
3984 ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) );
3985 if( ret != 0 )
3986 {
3987 /* It's ok to abort on an RNG failure, since this does not reveal
3988 * anything about the RSA decryption. */
3989 return( ret );
3990 }
3991
3992 #if defined(MBEDTLS_SSL_DEBUG_ALL)
3993 if( diff != 0 )
3994 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3995 #endif
3996
3997 if( sizeof( ssl->handshake->premaster ) < pms_offset ||
3998 sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
3999 {
4000 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4001 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4002 }
4003 ssl->handshake->pmslen = 48;
4004
4005 /* Set pms to either the true or the fake PMS, without
4006 * data-dependent branches. */
4007 for( i = 0; i < ssl->handshake->pmslen; i++ )
4008 pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
4009
4010 return( 0 );
4011 }
4012 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
4013 MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
4014
4015 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
ssl_parse_client_psk_identity(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)4016 static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p,
4017 const unsigned char *end )
4018 {
4019 int ret = 0;
4020 uint16_t n;
4021
4022 if( ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
4023 {
4024 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
4025 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
4026 }
4027
4028 /*
4029 * Receive client pre-shared key identity name
4030 */
4031 if( end - *p < 2 )
4032 {
4033 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4034 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4035 }
4036
4037 n = ( (*p)[0] << 8 ) | (*p)[1];
4038 *p += 2;
4039
4040 if( n == 0 || n > end - *p )
4041 {
4042 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4043 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4044 }
4045
4046 if( ssl->conf->f_psk != NULL )
4047 {
4048 if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 )
4049 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
4050 }
4051 else
4052 {
4053 /* Identity is not a big secret since clients send it in the clear,
4054 * but treat it carefully anyway, just in case */
4055 if( n != ssl->conf->psk_identity_len ||
4056 mbedtls_ssl_safer_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
4057 {
4058 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
4059 }
4060 }
4061
4062 if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
4063 {
4064 MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
4065 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
4066 MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
4067 return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
4068 }
4069
4070 *p += n;
4071
4072 return( 0 );
4073 }
4074 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
4075
ssl_parse_client_key_exchange(mbedtls_ssl_context * ssl)4076 static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
4077 {
4078 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4079 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
4080 unsigned char *p, *end;
4081
4082 ciphersuite_info = ssl->handshake->ciphersuite_info;
4083
4084 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
4085
4086 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
4087 ( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
4088 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
4089 if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
4090 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) &&
4091 ( ssl->handshake->async_in_progress != 0 ) )
4092 {
4093 /* We've already read a record and there is an asynchronous
4094 * operation in progress to decrypt it. So skip reading the
4095 * record. */
4096 MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) );
4097 }
4098 else
4099 #endif
4100 if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
4101 {
4102 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
4103 return( ret );
4104 }
4105
4106 p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
4107 end = ssl->in_msg + ssl->in_hslen;
4108
4109 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
4110 {
4111 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4112 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4113 }
4114
4115 if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
4116 {
4117 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4118 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4119 }
4120
4121 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
4122 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
4123 {
4124 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
4125 {
4126 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
4127 return( ret );
4128 }
4129
4130 if( p != end )
4131 {
4132 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4133 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4134 }
4135
4136 if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
4137 ssl->handshake->premaster,
4138 MBEDTLS_PREMASTER_SIZE,
4139 &ssl->handshake->pmslen,
4140 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
4141 {
4142 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
4143 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
4144 }
4145
4146 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
4147 }
4148 else
4149 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
4150 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
4151 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
4152 defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
4153 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
4154 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
4155 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
4156 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
4157 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
4158 {
4159 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
4160 p, end - p) ) != 0 )
4161 {
4162 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
4163 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
4164 }
4165
4166 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4167 MBEDTLS_DEBUG_ECDH_QP );
4168
4169 if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
4170 &ssl->handshake->pmslen,
4171 ssl->handshake->premaster,
4172 MBEDTLS_MPI_MAX_SIZE,
4173 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
4174 {
4175 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
4176 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
4177 }
4178
4179 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4180 MBEDTLS_DEBUG_ECDH_Z );
4181 }
4182 else
4183 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
4184 MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
4185 MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
4186 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
4187 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
4188 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
4189 {
4190 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4191 {
4192 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4193 return( ret );
4194 }
4195
4196 if( p != end )
4197 {
4198 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4199 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4200 }
4201
4202 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4203 /* For opaque PSKs, we perform the PSK-to-MS derivation atomatically
4204 * and skip the intermediate PMS. */
4205 if( ssl_use_opaque_psk( ssl ) == 1 )
4206 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skip PMS generation for opaque PSK" ) );
4207 else
4208 #endif /* MBEDTLS_USE_PSA_CRYPTO */
4209 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4210 ciphersuite_info->key_exchange ) ) != 0 )
4211 {
4212 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4213 return( ret );
4214 }
4215 }
4216 else
4217 #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
4218 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
4219 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
4220 {
4221 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
4222 if ( ssl->handshake->async_in_progress != 0 )
4223 {
4224 /* There is an asynchronous operation in progress to
4225 * decrypt the encrypted premaster secret, so skip
4226 * directly to resuming this operation. */
4227 MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) );
4228 /* Update p to skip the PSK identity. ssl_parse_encrypted_pms
4229 * won't actually use it, but maintain p anyway for robustness. */
4230 p += ssl->conf->psk_identity_len + 2;
4231 }
4232 else
4233 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
4234 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4235 {
4236 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4237 return( ret );
4238 }
4239
4240 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4241 /* Opaque PSKs are currently only supported for PSK-only. */
4242 if( ssl_use_opaque_psk( ssl ) == 1 )
4243 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4244 #endif
4245
4246 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
4247 {
4248 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
4249 return( ret );
4250 }
4251
4252 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4253 ciphersuite_info->key_exchange ) ) != 0 )
4254 {
4255 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4256 return( ret );
4257 }
4258 }
4259 else
4260 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
4261 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
4262 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
4263 {
4264 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4265 {
4266 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4267 return( ret );
4268 }
4269 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
4270 {
4271 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
4272 return( ret );
4273 }
4274
4275 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4276 /* Opaque PSKs are currently only supported for PSK-only. */
4277 if( ssl_use_opaque_psk( ssl ) == 1 )
4278 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4279 #endif
4280
4281 if( p != end )
4282 {
4283 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4284 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4285 }
4286
4287 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4288 ciphersuite_info->key_exchange ) ) != 0 )
4289 {
4290 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4291 return( ret );
4292 }
4293 }
4294 else
4295 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
4296 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
4297 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
4298 {
4299 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4300 {
4301 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4302 return( ret );
4303 }
4304
4305 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
4306 p, end - p ) ) != 0 )
4307 {
4308 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
4309 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
4310 }
4311
4312 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4313 /* Opaque PSKs are currently only supported for PSK-only. */
4314 if( ssl_use_opaque_psk( ssl ) == 1 )
4315 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4316 #endif
4317
4318 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4319 MBEDTLS_DEBUG_ECDH_QP );
4320
4321 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4322 ciphersuite_info->key_exchange ) ) != 0 )
4323 {
4324 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4325 return( ret );
4326 }
4327 }
4328 else
4329 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
4330 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
4331 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
4332 {
4333 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 )
4334 {
4335 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
4336 return( ret );
4337 }
4338 }
4339 else
4340 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
4341 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
4342 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
4343 {
4344 ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx,
4345 p, end - p );
4346 if( ret != 0 )
4347 {
4348 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
4349 return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
4350 }
4351
4352 ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
4353 ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
4354 ssl->conf->f_rng, ssl->conf->p_rng );
4355 if( ret != 0 )
4356 {
4357 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
4358 return( ret );
4359 }
4360 }
4361 else
4362 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
4363 {
4364 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4365 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4366 }
4367
4368 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
4369 {
4370 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
4371 return( ret );
4372 }
4373
4374 ssl->state++;
4375
4376 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
4377
4378 return( 0 );
4379 }
4380
4381 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4382 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4383 {
4384 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4385 ssl->handshake->ciphersuite_info;
4386
4387 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4388
4389 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4390 {
4391 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4392 ssl->state++;
4393 return( 0 );
4394 }
4395
4396 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4397 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4398 }
4399 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4400 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4401 {
4402 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
4403 size_t i, sig_len;
4404 unsigned char hash[48];
4405 unsigned char *hash_start = hash;
4406 size_t hashlen;
4407 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4408 mbedtls_pk_type_t pk_alg;
4409 #endif
4410 mbedtls_md_type_t md_alg;
4411 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4412 ssl->handshake->ciphersuite_info;
4413 mbedtls_pk_context * peer_pk;
4414
4415 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4416
4417 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4418 {
4419 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4420 ssl->state++;
4421 return( 0 );
4422 }
4423
4424 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4425 if( ssl->session_negotiate->peer_cert == NULL )
4426 {
4427 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4428 ssl->state++;
4429 return( 0 );
4430 }
4431 #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4432 if( ssl->session_negotiate->peer_cert_digest == NULL )
4433 {
4434 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4435 ssl->state++;
4436 return( 0 );
4437 }
4438 #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4439
4440 /* Read the message without adding it to the checksum */
4441 ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
4442 if( 0 != ret )
4443 {
4444 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
4445 return( ret );
4446 }
4447
4448 ssl->state++;
4449
4450 /* Process the message contents */
4451 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
4452 ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY )
4453 {
4454 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4455 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4456 }
4457
4458 i = mbedtls_ssl_hs_hdr_len( ssl );
4459
4460 #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4461 peer_pk = &ssl->handshake->peer_pubkey;
4462 #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4463 if( ssl->session_negotiate->peer_cert == NULL )
4464 {
4465 /* Should never happen */
4466 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4467 }
4468 peer_pk = &ssl->session_negotiate->peer_cert->pk;
4469 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4470
4471 /*
4472 * struct {
4473 * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
4474 * opaque signature<0..2^16-1>;
4475 * } DigitallySigned;
4476 */
4477 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
4478 defined(MBEDTLS_SSL_PROTO_TLS1_1)
4479 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 )
4480 {
4481 md_alg = MBEDTLS_MD_NONE;
4482 hashlen = 36;
4483
4484 /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
4485 if( mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECDSA ) )
4486 {
4487 hash_start += 16;
4488 hashlen -= 16;
4489 md_alg = MBEDTLS_MD_SHA1;
4490 }
4491 }
4492 else
4493 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 ||
4494 MBEDTLS_SSL_PROTO_TLS1_1 */
4495 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4496 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
4497 {
4498 if( i + 2 > ssl->in_hslen )
4499 {
4500 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4501 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4502 }
4503
4504 /*
4505 * Hash
4506 */
4507 md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] );
4508
4509 if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) )
4510 {
4511 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4512 " for verify message" ) );
4513 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4514 }
4515
4516 #if !defined(MBEDTLS_MD_SHA1)
4517 if( MBEDTLS_MD_SHA1 == md_alg )
4518 hash_start += 16;
4519 #endif
4520
4521 /* Info from md_alg will be used instead */
4522 hashlen = 0;
4523
4524 i++;
4525
4526 /*
4527 * Signature
4528 */
4529 if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) )
4530 == MBEDTLS_PK_NONE )
4531 {
4532 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4533 " for verify message" ) );
4534 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4535 }
4536
4537 /*
4538 * Check the certificate's key type matches the signature alg
4539 */
4540 if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
4541 {
4542 MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
4543 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4544 }
4545
4546 i++;
4547 }
4548 else
4549 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
4550 {
4551 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4552 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4553 }
4554
4555 if( i + 2 > ssl->in_hslen )
4556 {
4557 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4558 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4559 }
4560
4561 sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
4562 i += 2;
4563
4564 if( i + sig_len != ssl->in_hslen )
4565 {
4566 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4567 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4568 }
4569
4570 /* Calculate hash and verify signature */
4571 {
4572 size_t dummy_hlen;
4573 ssl->handshake->calc_verify( ssl, hash, &dummy_hlen );
4574 }
4575
4576 if( ( ret = mbedtls_pk_verify( peer_pk,
4577 md_alg, hash_start, hashlen,
4578 ssl->in_msg + i, sig_len ) ) != 0 )
4579 {
4580 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
4581 return( ret );
4582 }
4583
4584 mbedtls_ssl_update_handshake_status( ssl );
4585
4586 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
4587
4588 return( ret );
4589 }
4590 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
4591
4592 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_new_session_ticket(mbedtls_ssl_context * ssl)4593 static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
4594 {
4595 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4596 size_t tlen;
4597 uint32_t lifetime;
4598
4599 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
4600
4601 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
4602 ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
4603
4604 /*
4605 * struct {
4606 * uint32 ticket_lifetime_hint;
4607 * opaque ticket<0..2^16-1>;
4608 * } NewSessionTicket;
4609 *
4610 * 4 . 7 ticket_lifetime_hint (0 = unspecified)
4611 * 8 . 9 ticket_len (n)
4612 * 10 . 9+n ticket content
4613 */
4614
4615 if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
4616 ssl->session_negotiate,
4617 ssl->out_msg + 10,
4618 ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
4619 &tlen, &lifetime ) ) != 0 )
4620 {
4621 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
4622 tlen = 0;
4623 }
4624
4625 ssl->out_msg[4] = ( lifetime >> 24 ) & 0xFF;
4626 ssl->out_msg[5] = ( lifetime >> 16 ) & 0xFF;
4627 ssl->out_msg[6] = ( lifetime >> 8 ) & 0xFF;
4628 ssl->out_msg[7] = ( lifetime ) & 0xFF;
4629
4630 ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF );
4631 ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF );
4632
4633 ssl->out_msglen = 10 + tlen;
4634
4635 /*
4636 * Morally equivalent to updating ssl->state, but NewSessionTicket and
4637 * ChangeCipherSpec share the same state.
4638 */
4639 ssl->handshake->new_session_ticket = 0;
4640
4641 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
4642 {
4643 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
4644 return( ret );
4645 }
4646
4647 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
4648
4649 return( 0 );
4650 }
4651 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
4652
4653 /*
4654 * SSL handshake -- server side -- single step
4655 */
mbedtls_ssl_handshake_server_step(mbedtls_ssl_context * ssl)4656 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
4657 {
4658 int ret = 0;
4659
4660 if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
4661 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4662
4663 MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
4664
4665 if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
4666 return( ret );
4667
4668 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4669 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
4670 ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
4671 {
4672 if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
4673 return( ret );
4674 }
4675 #endif /* MBEDTLS_SSL_PROTO_DTLS */
4676
4677 switch( ssl->state )
4678 {
4679 case MBEDTLS_SSL_HELLO_REQUEST:
4680 ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
4681 break;
4682
4683 /*
4684 * <== ClientHello
4685 */
4686 case MBEDTLS_SSL_CLIENT_HELLO:
4687 ret = ssl_parse_client_hello( ssl );
4688 break;
4689
4690 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4691 case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
4692 return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
4693 #endif
4694
4695 /*
4696 * ==> ServerHello
4697 * Certificate
4698 * ( ServerKeyExchange )
4699 * ( CertificateRequest )
4700 * ServerHelloDone
4701 */
4702 case MBEDTLS_SSL_SERVER_HELLO:
4703 ret = ssl_write_server_hello( ssl );
4704 break;
4705
4706 case MBEDTLS_SSL_SERVER_CERTIFICATE:
4707 ret = mbedtls_ssl_write_certificate( ssl );
4708 break;
4709
4710 case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
4711 ret = ssl_write_server_key_exchange( ssl );
4712 break;
4713
4714 case MBEDTLS_SSL_CERTIFICATE_REQUEST:
4715 ret = ssl_write_certificate_request( ssl );
4716 break;
4717
4718 case MBEDTLS_SSL_SERVER_HELLO_DONE:
4719 ret = ssl_write_server_hello_done( ssl );
4720 break;
4721
4722 /*
4723 * <== ( Certificate/Alert )
4724 * ClientKeyExchange
4725 * ( CertificateVerify )
4726 * ChangeCipherSpec
4727 * Finished
4728 */
4729 case MBEDTLS_SSL_CLIENT_CERTIFICATE:
4730 ret = mbedtls_ssl_parse_certificate( ssl );
4731 break;
4732
4733 case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
4734 ret = ssl_parse_client_key_exchange( ssl );
4735 break;
4736
4737 case MBEDTLS_SSL_CERTIFICATE_VERIFY:
4738 ret = ssl_parse_certificate_verify( ssl );
4739 break;
4740
4741 case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
4742 ret = mbedtls_ssl_parse_change_cipher_spec( ssl );
4743 break;
4744
4745 case MBEDTLS_SSL_CLIENT_FINISHED:
4746 ret = mbedtls_ssl_parse_finished( ssl );
4747 break;
4748
4749 /*
4750 * ==> ( NewSessionTicket )
4751 * ChangeCipherSpec
4752 * Finished
4753 */
4754 case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
4755 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
4756 if( ssl->handshake->new_session_ticket != 0 )
4757 ret = ssl_write_new_session_ticket( ssl );
4758 else
4759 #endif
4760 ret = mbedtls_ssl_write_change_cipher_spec( ssl );
4761 break;
4762
4763 case MBEDTLS_SSL_SERVER_FINISHED:
4764 ret = mbedtls_ssl_write_finished( ssl );
4765 break;
4766
4767 case MBEDTLS_SSL_FLUSH_BUFFERS:
4768 MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
4769 ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
4770 break;
4771
4772 case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
4773 mbedtls_ssl_handshake_wrapup( ssl );
4774 break;
4775
4776 default:
4777 MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
4778 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4779 }
4780
4781 return( ret );
4782 }
4783 #endif /* MBEDTLS_SSL_SRV_C */
4784