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( msg_len != ext_offset + 2 + ext_len )
1891 {
1892 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1893 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1894 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1895 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1896 }
1897 }
1898 else
1899 ext_len = 0;
1900
1901 ext = buf + ext_offset + 2;
1902 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len );
1903
1904 while( ext_len != 0 )
1905 {
1906 unsigned int ext_id;
1907 unsigned int ext_size;
1908 if ( ext_len < 4 ) {
1909 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1910 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1911 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1912 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1913 }
1914 ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) );
1915 ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) );
1916
1917 if( ext_size + 4 > ext_len )
1918 {
1919 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1920 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1921 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1922 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1923 }
1924 switch( ext_id )
1925 {
1926 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
1927 case MBEDTLS_TLS_EXT_SERVERNAME:
1928 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
1929 if( ssl->conf->f_sni == NULL )
1930 break;
1931
1932 ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size );
1933 if( ret != 0 )
1934 return( ret );
1935 break;
1936 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
1937
1938 case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO:
1939 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
1940 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1941 renegotiation_info_seen = 1;
1942 #endif
1943
1944 ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
1945 if( ret != 0 )
1946 return( ret );
1947 break;
1948
1949 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1950 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1951 case MBEDTLS_TLS_EXT_SIG_ALG:
1952 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
1953
1954 ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
1955 if( ret != 0 )
1956 return( ret );
1957
1958 sig_hash_alg_ext_present = 1;
1959 break;
1960 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1961 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1962
1963 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
1964 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1965 case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
1966 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
1967
1968 ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
1969 if( ret != 0 )
1970 return( ret );
1971 break;
1972
1973 case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS:
1974 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) );
1975 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
1976
1977 ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size );
1978 if( ret != 0 )
1979 return( ret );
1980 break;
1981 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
1982 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1983
1984 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1985 case MBEDTLS_TLS_EXT_ECJPAKE_KKPP:
1986 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ecjpake kkpp extension" ) );
1987
1988 ret = ssl_parse_ecjpake_kkpp( ssl, ext + 4, ext_size );
1989 if( ret != 0 )
1990 return( ret );
1991 break;
1992 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1993
1994 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
1995 case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH:
1996 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
1997
1998 ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size );
1999 if( ret != 0 )
2000 return( ret );
2001 break;
2002 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2003
2004 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2005 case MBEDTLS_TLS_EXT_TRUNCATED_HMAC:
2006 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
2007
2008 ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size );
2009 if( ret != 0 )
2010 return( ret );
2011 break;
2012 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2013
2014 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2015 case MBEDTLS_TLS_EXT_CID:
2016 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found CID extension" ) );
2017
2018 ret = ssl_parse_cid_ext( ssl, ext + 4, ext_size );
2019 if( ret != 0 )
2020 return( ret );
2021 break;
2022 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2023
2024 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2025 case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
2026 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
2027
2028 ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
2029 if( ret != 0 )
2030 return( ret );
2031 break;
2032 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2033
2034 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2035 case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET:
2036 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
2037
2038 ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size );
2039 if( ret != 0 )
2040 return( ret );
2041 break;
2042 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2043
2044 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2045 case MBEDTLS_TLS_EXT_SESSION_TICKET:
2046 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) );
2047
2048 ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size );
2049 if( ret != 0 )
2050 return( ret );
2051 break;
2052 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2053
2054 #if defined(MBEDTLS_SSL_ALPN)
2055 case MBEDTLS_TLS_EXT_ALPN:
2056 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );
2057
2058 ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
2059 if( ret != 0 )
2060 return( ret );
2061 break;
2062 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2063
2064 #if defined(MBEDTLS_SSL_DTLS_SRTP)
2065 case MBEDTLS_TLS_EXT_USE_SRTP:
2066 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found use_srtp extension" ) );
2067
2068 ret = ssl_parse_use_srtp_ext( ssl, ext + 4, ext_size );
2069 if( ret != 0 )
2070 return( ret );
2071 break;
2072 #endif /* MBEDTLS_SSL_DTLS_SRTP */
2073
2074 default:
2075 MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %u (ignoring)",
2076 ext_id ) );
2077 }
2078
2079 ext_len -= 4 + ext_size;
2080 ext += 4 + ext_size;
2081 }
2082 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2083 }
2084 #endif
2085
2086 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
2087 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
2088 {
2089 if( p[0] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
2090 p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
2091 {
2092 MBEDTLS_SSL_DEBUG_MSG( 2, ( "received FALLBACK_SCSV" ) );
2093
2094 if( ssl->minor_ver < ssl->conf->max_minor_ver )
2095 {
2096 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
2097
2098 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2099 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
2100
2101 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2102 }
2103
2104 break;
2105 }
2106 }
2107 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
2108
2109 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2110 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
2111
2112 /*
2113 * Try to fall back to default hash SHA1 if the client
2114 * hasn't provided any preferred signature-hash combinations.
2115 */
2116 if( sig_hash_alg_ext_present == 0 )
2117 {
2118 mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1;
2119
2120 if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 )
2121 md_default = MBEDTLS_MD_NONE;
2122
2123 mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default );
2124 }
2125
2126 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
2127 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
2128
2129 /*
2130 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
2131 */
2132 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
2133 {
2134 if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
2135 {
2136 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
2137 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2138 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
2139 {
2140 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
2141 "during renegotiation" ) );
2142 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2143 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2144 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2145 }
2146 #endif
2147 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
2148 break;
2149 }
2150 }
2151
2152 /*
2153 * Renegotiation security checks
2154 */
2155 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
2156 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
2157 {
2158 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
2159 handshake_failure = 1;
2160 }
2161 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2162 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2163 ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
2164 renegotiation_info_seen == 0 )
2165 {
2166 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
2167 handshake_failure = 1;
2168 }
2169 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2170 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
2171 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION )
2172 {
2173 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
2174 handshake_failure = 1;
2175 }
2176 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2177 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
2178 renegotiation_info_seen == 1 )
2179 {
2180 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
2181 handshake_failure = 1;
2182 }
2183 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2184
2185 if( handshake_failure == 1 )
2186 {
2187 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2188 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2189 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2190 }
2191
2192 /*
2193 * Search for a matching ciphersuite
2194 * (At the end because we need information from the EC-based extensions
2195 * and certificate from the SNI callback triggered by the SNI extension.)
2196 */
2197 got_common_suite = 0;
2198 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
2199 ciphersuite_info = NULL;
2200 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
2201 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
2202 for( i = 0; ciphersuites[i] != 0; i++ )
2203 #else
2204 for( i = 0; ciphersuites[i] != 0; i++ )
2205 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
2206 #endif
2207 {
2208 if( p[0] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
2209 p[1] != ( ( ciphersuites[i] ) & 0xFF ) )
2210 continue;
2211
2212 got_common_suite = 1;
2213
2214 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
2215 &ciphersuite_info ) ) != 0 )
2216 return( ret );
2217
2218 if( ciphersuite_info != NULL )
2219 goto have_ciphersuite;
2220 }
2221
2222 if( got_common_suite )
2223 {
2224 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
2225 "but none of them usable" ) );
2226 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2227 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2228 return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
2229 }
2230 else
2231 {
2232 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
2233 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2234 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2235 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
2236 }
2237
2238 have_ciphersuite:
2239 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
2240
2241 ssl->session_negotiate->ciphersuite = ciphersuites[i];
2242 ssl->handshake->ciphersuite_info = ciphersuite_info;
2243
2244 ssl->state++;
2245
2246 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2247 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
2248 mbedtls_ssl_recv_flight_completed( ssl );
2249 #endif
2250
2251 /* Debugging-only output for testsuite */
2252 #if defined(MBEDTLS_DEBUG_C) && \
2253 defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2254 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
2255 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
2256 {
2257 mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info );
2258 if( sig_alg != MBEDTLS_PK_NONE )
2259 {
2260 mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
2261 sig_alg );
2262 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
2263 mbedtls_ssl_hash_from_md_alg( md_alg ) ) );
2264 }
2265 else
2266 {
2267 MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm "
2268 "%u - should not happen", (unsigned) sig_alg ) );
2269 }
2270 }
2271 #endif
2272
2273 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
2274
2275 return( 0 );
2276 }
2277
2278 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_write_truncated_hmac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2279 static void ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl,
2280 unsigned char *buf,
2281 size_t *olen )
2282 {
2283 unsigned char *p = buf;
2284
2285 if( ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED )
2286 {
2287 *olen = 0;
2288 return;
2289 }
2290
2291 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) );
2292
2293 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
2294 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC ) & 0xFF );
2295
2296 *p++ = 0x00;
2297 *p++ = 0x00;
2298
2299 *olen = 4;
2300 }
2301 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2302
2303 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_write_cid_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2304 static void ssl_write_cid_ext( mbedtls_ssl_context *ssl,
2305 unsigned char *buf,
2306 size_t *olen )
2307 {
2308 unsigned char *p = buf;
2309 size_t ext_len;
2310 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2311
2312 *olen = 0;
2313
2314 /* Skip writing the extension if we don't want to use it or if
2315 * the client hasn't offered it. */
2316 if( ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED )
2317 return;
2318
2319 /* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX
2320 * which is at most 255, so the increment cannot overflow. */
2321 if( end < p || (size_t)( end - p ) < (unsigned)( ssl->own_cid_len + 5 ) )
2322 {
2323 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2324 return;
2325 }
2326
2327 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding CID extension" ) );
2328
2329 /*
2330 * Quoting draft-ietf-tls-dtls-connection-id-05
2331 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
2332 *
2333 * struct {
2334 * opaque cid<0..2^8-1>;
2335 * } ConnectionId;
2336 */
2337
2338 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_CID >> 8 ) & 0xFF );
2339 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_CID ) & 0xFF );
2340 ext_len = (size_t) ssl->own_cid_len + 1;
2341 *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
2342 *p++ = (unsigned char)( ( ext_len ) & 0xFF );
2343
2344 *p++ = (uint8_t) ssl->own_cid_len;
2345 memcpy( p, ssl->own_cid, ssl->own_cid_len );
2346
2347 *olen = ssl->own_cid_len + 5;
2348 }
2349 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
2350
2351 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2352 static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
2353 unsigned char *buf,
2354 size_t *olen )
2355 {
2356 unsigned char *p = buf;
2357 const mbedtls_ssl_ciphersuite_t *suite = NULL;
2358 const mbedtls_cipher_info_t *cipher = NULL;
2359
2360 if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ||
2361 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2362 {
2363 *olen = 0;
2364 return;
2365 }
2366
2367 /*
2368 * RFC 7366: "If a server receives an encrypt-then-MAC request extension
2369 * from a client and then selects a stream or Authenticated Encryption
2370 * with Associated Data (AEAD) ciphersuite, it MUST NOT send an
2371 * encrypt-then-MAC response extension back to the client."
2372 */
2373 if( ( suite = mbedtls_ssl_ciphersuite_from_id(
2374 ssl->session_negotiate->ciphersuite ) ) == NULL ||
2375 ( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL ||
2376 cipher->mode != MBEDTLS_MODE_CBC )
2377 {
2378 *olen = 0;
2379 return;
2380 }
2381
2382 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
2383
2384 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
2385 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
2386
2387 *p++ = 0x00;
2388 *p++ = 0x00;
2389
2390 *olen = 4;
2391 }
2392 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2393
2394 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2395 static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
2396 unsigned char *buf,
2397 size_t *olen )
2398 {
2399 unsigned char *p = buf;
2400
2401 if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED ||
2402 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2403 {
2404 *olen = 0;
2405 return;
2406 }
2407
2408 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
2409 "extension" ) );
2410
2411 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
2412 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF );
2413
2414 *p++ = 0x00;
2415 *p++ = 0x00;
2416
2417 *olen = 4;
2418 }
2419 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2420
2421 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2422 static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
2423 unsigned char *buf,
2424 size_t *olen )
2425 {
2426 unsigned char *p = buf;
2427
2428 if( ssl->handshake->new_session_ticket == 0 )
2429 {
2430 *olen = 0;
2431 return;
2432 }
2433
2434 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
2435
2436 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
2437 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET ) & 0xFF );
2438
2439 *p++ = 0x00;
2440 *p++ = 0x00;
2441
2442 *olen = 4;
2443 }
2444 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2445
ssl_write_renegotiation_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2446 static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
2447 unsigned char *buf,
2448 size_t *olen )
2449 {
2450 unsigned char *p = buf;
2451
2452 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION )
2453 {
2454 *olen = 0;
2455 return;
2456 }
2457
2458 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) );
2459
2460 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF );
2461 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ) & 0xFF );
2462
2463 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2464 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2465 {
2466 *p++ = 0x00;
2467 *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF;
2468 *p++ = ssl->verify_data_len * 2 & 0xFF;
2469
2470 memcpy( p, ssl->peer_verify_data, ssl->verify_data_len );
2471 p += ssl->verify_data_len;
2472 memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
2473 p += ssl->verify_data_len;
2474 }
2475 else
2476 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2477 {
2478 *p++ = 0x00;
2479 *p++ = 0x01;
2480 *p++ = 0x00;
2481 }
2482
2483 *olen = p - buf;
2484 }
2485
2486 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2487 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
2488 unsigned char *buf,
2489 size_t *olen )
2490 {
2491 unsigned char *p = buf;
2492
2493 if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE )
2494 {
2495 *olen = 0;
2496 return;
2497 }
2498
2499 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
2500
2501 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF );
2502 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF );
2503
2504 *p++ = 0x00;
2505 *p++ = 1;
2506
2507 *p++ = ssl->session_negotiate->mfl_code;
2508
2509 *olen = 5;
2510 }
2511 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2512
2513 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2514 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_supported_point_formats_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2515 static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
2516 unsigned char *buf,
2517 size_t *olen )
2518 {
2519 unsigned char *p = buf;
2520 ((void) ssl);
2521
2522 if( ( ssl->handshake->cli_exts &
2523 MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
2524 {
2525 *olen = 0;
2526 return;
2527 }
2528
2529 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
2530
2531 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
2532 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF );
2533
2534 *p++ = 0x00;
2535 *p++ = 2;
2536
2537 *p++ = 1;
2538 *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
2539
2540 *olen = 6;
2541 }
2542 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2543
2544 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2545 static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
2546 unsigned char *buf,
2547 size_t *olen )
2548 {
2549 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2550 unsigned char *p = buf;
2551 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2552 size_t kkpp_len;
2553
2554 *olen = 0;
2555
2556 /* Skip costly computation if not needed */
2557 if( ssl->handshake->ciphersuite_info->key_exchange !=
2558 MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2559 return;
2560
2561 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, ecjpake kkpp extension" ) );
2562
2563 if( end - p < 4 )
2564 {
2565 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2566 return;
2567 }
2568
2569 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP >> 8 ) & 0xFF );
2570 *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ) & 0xFF );
2571
2572 ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
2573 p + 2, end - p - 2, &kkpp_len,
2574 ssl->conf->f_rng, ssl->conf->p_rng );
2575 if( ret != 0 )
2576 {
2577 MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
2578 return;
2579 }
2580
2581 *p++ = (unsigned char)( ( kkpp_len >> 8 ) & 0xFF );
2582 *p++ = (unsigned char)( ( kkpp_len ) & 0xFF );
2583
2584 *olen = kkpp_len + 4;
2585 }
2586 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2587
2588 #if defined(MBEDTLS_SSL_ALPN )
ssl_write_alpn_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2589 static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
2590 unsigned char *buf, size_t *olen )
2591 {
2592 if( ssl->alpn_chosen == NULL )
2593 {
2594 *olen = 0;
2595 return;
2596 }
2597
2598 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
2599
2600 /*
2601 * 0 . 1 ext identifier
2602 * 2 . 3 ext length
2603 * 4 . 5 protocol list length
2604 * 6 . 6 protocol name length
2605 * 7 . 7+n protocol name
2606 */
2607 buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF );
2608 buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN ) & 0xFF );
2609
2610 *olen = 7 + strlen( ssl->alpn_chosen );
2611
2612 buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
2613 buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF );
2614
2615 buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
2616 buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF );
2617
2618 buf[6] = (unsigned char)( ( ( *olen - 7 ) ) & 0xFF );
2619
2620 memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
2621 }
2622 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
2623
2624 #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)2625 static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
2626 unsigned char *buf,
2627 size_t *olen )
2628 {
2629 size_t mki_len = 0, ext_len = 0;
2630 uint16_t profile_value = 0;
2631 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2632
2633 *olen = 0;
2634
2635 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
2636 ( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET ) )
2637 {
2638 return;
2639 }
2640
2641 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding use_srtp extension" ) );
2642
2643 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED )
2644 {
2645 mki_len = ssl->dtls_srtp_info.mki_len;
2646 }
2647
2648 /* The extension total size is 9 bytes :
2649 * - 2 bytes for the extension tag
2650 * - 2 bytes for the total size
2651 * - 2 bytes for the protection profile length
2652 * - 2 bytes for the protection profile
2653 * - 1 byte for the mki length
2654 * + the actual mki length
2655 * Check we have enough room in the output buffer */
2656 if( (size_t)( end - buf ) < mki_len + 9 )
2657 {
2658 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2659 return;
2660 }
2661
2662 /* extension */
2663 buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP >> 8 ) & 0xFF );
2664 buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP ) & 0xFF );
2665 /*
2666 * total length 5 and mki value: only one profile(2 bytes)
2667 * and length(2 bytes) and srtp_mki )
2668 */
2669 ext_len = 5 + mki_len;
2670 buf[2] = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
2671 buf[3] = (unsigned char)( ext_len & 0xFF );
2672
2673 /* protection profile length: 2 */
2674 buf[4] = 0x00;
2675 buf[5] = 0x02;
2676 profile_value = mbedtls_ssl_check_srtp_profile_value(
2677 ssl->dtls_srtp_info.chosen_dtls_srtp_profile );
2678 if( profile_value != MBEDTLS_TLS_SRTP_UNSET )
2679 {
2680 buf[6] = (unsigned char)( ( profile_value >> 8 ) & 0xFF );
2681 buf[7] = (unsigned char)( profile_value & 0xFF );
2682 }
2683 else
2684 {
2685 MBEDTLS_SSL_DEBUG_MSG( 1, ( "use_srtp extension invalid profile" ) );
2686 return;
2687 }
2688
2689 buf[8] = mki_len & 0xFF;
2690 memcpy( &buf[9], ssl->dtls_srtp_info.mki_value, mki_len );
2691
2692 *olen = 9 + mki_len;
2693 }
2694 #endif /* MBEDTLS_SSL_DTLS_SRTP */
2695
2696 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
ssl_write_hello_verify_request(mbedtls_ssl_context * ssl)2697 static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
2698 {
2699 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2700 unsigned char *p = ssl->out_msg + 4;
2701 unsigned char *cookie_len_byte;
2702
2703 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) );
2704
2705 /*
2706 * struct {
2707 * ProtocolVersion server_version;
2708 * opaque cookie<0..2^8-1>;
2709 * } HelloVerifyRequest;
2710 */
2711
2712 /* The RFC is not clear on this point, but sending the actual negotiated
2713 * version looks like the most interoperable thing to do. */
2714 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2715 ssl->conf->transport, p );
2716 MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 );
2717 p += 2;
2718
2719 /* If we get here, f_cookie_check is not null */
2720 if( ssl->conf->f_cookie_write == NULL )
2721 {
2722 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) );
2723 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2724 }
2725
2726 /* Skip length byte until we know the length */
2727 cookie_len_byte = p++;
2728
2729 if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
2730 &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
2731 ssl->cli_id, ssl->cli_id_len ) ) != 0 )
2732 {
2733 MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
2734 return( ret );
2735 }
2736
2737 *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) );
2738
2739 MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte );
2740
2741 ssl->out_msglen = p - ssl->out_msg;
2742 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2743 ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
2744
2745 ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
2746
2747 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
2748 {
2749 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
2750 return( ret );
2751 }
2752
2753 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2754 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2755 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
2756 {
2757 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
2758 return( ret );
2759 }
2760 #endif /* MBEDTLS_SSL_PROTO_DTLS */
2761
2762 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
2763
2764 return( 0 );
2765 }
2766 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2767
ssl_handle_id_based_session_resumption(mbedtls_ssl_context * ssl)2768 static void ssl_handle_id_based_session_resumption( mbedtls_ssl_context *ssl )
2769 {
2770 int ret;
2771 mbedtls_ssl_session session_tmp;
2772 mbedtls_ssl_session * const session = ssl->session_negotiate;
2773
2774 /* Resume is 0 by default, see ssl_handshake_init().
2775 * It may be already set to 1 by ssl_parse_session_ticket_ext(). */
2776 if( ssl->handshake->resume == 1 )
2777 return;
2778 if( session->id_len == 0 )
2779 return;
2780 if( ssl->conf->f_get_cache == NULL )
2781 return;
2782 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2783 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2784 return;
2785 #endif
2786
2787 mbedtls_ssl_session_init( &session_tmp );
2788
2789 session_tmp.id_len = session->id_len;
2790 memcpy( session_tmp.id, session->id, session->id_len );
2791
2792 ret = ssl->conf->f_get_cache( ssl->conf->p_cache,
2793 &session_tmp );
2794 if( ret != 0 )
2795 goto exit;
2796
2797 if( session->ciphersuite != session_tmp.ciphersuite ||
2798 session->compression != session_tmp.compression )
2799 {
2800 /* Mismatch between cached and negotiated session */
2801 goto exit;
2802 }
2803
2804 /* Move semantics */
2805 mbedtls_ssl_session_free( session );
2806 *session = session_tmp;
2807 memset( &session_tmp, 0, sizeof( session_tmp ) );
2808
2809 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
2810 ssl->handshake->resume = 1;
2811
2812 exit:
2813
2814 mbedtls_ssl_session_free( &session_tmp );
2815 }
2816
ssl_write_server_hello(mbedtls_ssl_context * ssl)2817 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
2818 {
2819 #if defined(MBEDTLS_HAVE_TIME)
2820 mbedtls_time_t t;
2821 #endif
2822 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2823 size_t olen, ext_len = 0, n;
2824 unsigned char *buf, *p;
2825
2826 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
2827
2828 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
2829 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2830 ssl->handshake->verify_cookie_len != 0 )
2831 {
2832 MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) );
2833 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2834
2835 return( ssl_write_hello_verify_request( ssl ) );
2836 }
2837 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2838
2839 if( ssl->conf->f_rng == NULL )
2840 {
2841 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
2842 return( MBEDTLS_ERR_SSL_NO_RNG );
2843 }
2844
2845 /*
2846 * 0 . 0 handshake type
2847 * 1 . 3 handshake length
2848 * 4 . 5 protocol version
2849 * 6 . 9 UNIX time()
2850 * 10 . 37 random bytes
2851 */
2852 buf = ssl->out_msg;
2853 p = buf + 4;
2854
2855 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2856 ssl->conf->transport, p );
2857 p += 2;
2858
2859 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
2860 buf[4], buf[5] ) );
2861
2862 #if defined(MBEDTLS_HAVE_TIME)
2863 t = mbedtls_time( NULL );
2864 *p++ = (unsigned char)( t >> 24 );
2865 *p++ = (unsigned char)( t >> 16 );
2866 *p++ = (unsigned char)( t >> 8 );
2867 *p++ = (unsigned char)( t );
2868
2869 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
2870 (long long) t ) );
2871 #else
2872 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 )
2873 return( ret );
2874
2875 p += 4;
2876 #endif /* MBEDTLS_HAVE_TIME */
2877
2878 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 )
2879 return( ret );
2880
2881 p += 28;
2882
2883 memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
2884
2885 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
2886
2887 ssl_handle_id_based_session_resumption( ssl );
2888
2889 if( ssl->handshake->resume == 0 )
2890 {
2891 /*
2892 * New session, create a new session id,
2893 * unless we're about to issue a session ticket
2894 */
2895 ssl->state++;
2896
2897 #if defined(MBEDTLS_HAVE_TIME)
2898 ssl->session_negotiate->start = mbedtls_time( NULL );
2899 #endif
2900
2901 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2902 if( ssl->handshake->new_session_ticket != 0 )
2903 {
2904 ssl->session_negotiate->id_len = n = 0;
2905 memset( ssl->session_negotiate->id, 0, 32 );
2906 }
2907 else
2908 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2909 {
2910 ssl->session_negotiate->id_len = n = 32;
2911 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id,
2912 n ) ) != 0 )
2913 return( ret );
2914 }
2915 }
2916 else
2917 {
2918 /*
2919 * Resuming a session
2920 */
2921 n = ssl->session_negotiate->id_len;
2922 ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
2923
2924 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
2925 {
2926 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
2927 return( ret );
2928 }
2929 }
2930
2931 /*
2932 * 38 . 38 session id length
2933 * 39 . 38+n session id
2934 * 39+n . 40+n chosen ciphersuite
2935 * 41+n . 41+n chosen compression alg.
2936 * 42+n . 43+n extensions length
2937 * 44+n . 43+n+m extensions
2938 */
2939 *p++ = (unsigned char) ssl->session_negotiate->id_len;
2940 memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
2941 p += ssl->session_negotiate->id_len;
2942
2943 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n ) );
2944 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
2945 MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
2946 ssl->handshake->resume ? "a" : "no" ) );
2947
2948 *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 );
2949 *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite );
2950 *p++ = (unsigned char)( ssl->session_negotiate->compression );
2951
2952 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s",
2953 mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
2954 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
2955 (unsigned int) ssl->session_negotiate->compression ) );
2956
2957 /* Do not write the extensions if the protocol is SSLv3 */
2958 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2959 if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
2960 {
2961 #endif
2962
2963 /*
2964 * First write extensions, then the total length
2965 */
2966 ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
2967 ext_len += olen;
2968
2969 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2970 ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
2971 ext_len += olen;
2972 #endif
2973
2974 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2975 ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
2976 ext_len += olen;
2977 #endif
2978
2979 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2980 ssl_write_cid_ext( ssl, p + 2 + ext_len, &olen );
2981 ext_len += olen;
2982 #endif
2983
2984 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2985 ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
2986 ext_len += olen;
2987 #endif
2988
2989 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2990 ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
2991 ext_len += olen;
2992 #endif
2993
2994 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2995 ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
2996 ext_len += olen;
2997 #endif
2998
2999 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
3000 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3001 if ( mbedtls_ssl_ciphersuite_uses_ec(
3002 mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
3003 {
3004 ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
3005 ext_len += olen;
3006 }
3007 #endif
3008
3009 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3010 ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
3011 ext_len += olen;
3012 #endif
3013
3014 #if defined(MBEDTLS_SSL_ALPN)
3015 ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
3016 ext_len += olen;
3017 #endif
3018
3019 #if defined(MBEDTLS_SSL_DTLS_SRTP)
3020 ssl_write_use_srtp_ext( ssl, p + 2 + ext_len, &olen );
3021 ext_len += olen;
3022 #endif
3023
3024 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %" MBEDTLS_PRINTF_SIZET,
3025 ext_len ) );
3026
3027 if( ext_len > 0 )
3028 {
3029 *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
3030 *p++ = (unsigned char)( ( ext_len ) & 0xFF );
3031 p += ext_len;
3032 }
3033
3034 #if defined(MBEDTLS_SSL_PROTO_SSL3)
3035 }
3036 #endif
3037
3038 ssl->out_msglen = p - buf;
3039 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3040 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
3041
3042 ret = mbedtls_ssl_write_handshake_msg( ssl );
3043
3044 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
3045
3046 return( ret );
3047 }
3048
3049 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_write_certificate_request(mbedtls_ssl_context * ssl)3050 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
3051 {
3052 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3053 ssl->handshake->ciphersuite_info;
3054
3055 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
3056
3057 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
3058 {
3059 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
3060 ssl->state++;
3061 return( 0 );
3062 }
3063
3064 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3065 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3066 }
3067 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_write_certificate_request(mbedtls_ssl_context * ssl)3068 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
3069 {
3070 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3071 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3072 ssl->handshake->ciphersuite_info;
3073 uint16_t dn_size, total_dn_size; /* excluding length bytes */
3074 size_t ct_len, sa_len; /* including length bytes */
3075 unsigned char *buf, *p;
3076 const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
3077 const mbedtls_x509_crt *crt;
3078 int authmode;
3079
3080 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
3081
3082 ssl->state++;
3083
3084 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
3085 if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
3086 authmode = ssl->handshake->sni_authmode;
3087 else
3088 #endif
3089 authmode = ssl->conf->authmode;
3090
3091 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ||
3092 authmode == MBEDTLS_SSL_VERIFY_NONE )
3093 {
3094 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
3095 return( 0 );
3096 }
3097
3098 /*
3099 * 0 . 0 handshake type
3100 * 1 . 3 handshake length
3101 * 4 . 4 cert type count
3102 * 5 .. m-1 cert types
3103 * m .. m+1 sig alg length (TLS 1.2 only)
3104 * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
3105 * n .. n+1 length of all DNs
3106 * n+2 .. n+3 length of DN 1
3107 * n+4 .. ... Distinguished Name #1
3108 * ... .. ... length of DN 2, etc.
3109 */
3110 buf = ssl->out_msg;
3111 p = buf + 4;
3112
3113 /*
3114 * Supported certificate types
3115 *
3116 * ClientCertificateType certificate_types<1..2^8-1>;
3117 * enum { (255) } ClientCertificateType;
3118 */
3119 ct_len = 0;
3120
3121 #if defined(MBEDTLS_RSA_C)
3122 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
3123 #endif
3124 #if defined(MBEDTLS_ECDSA_C)
3125 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
3126 #endif
3127
3128 p[0] = (unsigned char) ct_len++;
3129 p += ct_len;
3130
3131 sa_len = 0;
3132 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3133 /*
3134 * Add signature_algorithms for verify (TLS 1.2)
3135 *
3136 * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
3137 *
3138 * struct {
3139 * HashAlgorithm hash;
3140 * SignatureAlgorithm signature;
3141 * } SignatureAndHashAlgorithm;
3142 *
3143 * enum { (255) } HashAlgorithm;
3144 * enum { (255) } SignatureAlgorithm;
3145 */
3146 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3147 {
3148 const int *cur;
3149
3150 /*
3151 * Supported signature algorithms
3152 */
3153 for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ )
3154 {
3155 unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur );
3156
3157 if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) )
3158 continue;
3159
3160 #if defined(MBEDTLS_RSA_C)
3161 p[2 + sa_len++] = hash;
3162 p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA;
3163 #endif
3164 #if defined(MBEDTLS_ECDSA_C)
3165 p[2 + sa_len++] = hash;
3166 p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA;
3167 #endif
3168 }
3169
3170 p[0] = (unsigned char)( sa_len >> 8 );
3171 p[1] = (unsigned char)( sa_len );
3172 sa_len += 2;
3173 p += sa_len;
3174 }
3175 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3176
3177 /*
3178 * DistinguishedName certificate_authorities<0..2^16-1>;
3179 * opaque DistinguishedName<1..2^16-1>;
3180 */
3181 p += 2;
3182
3183 total_dn_size = 0;
3184
3185 if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED )
3186 {
3187 /* NOTE: If trusted certificates are provisioned
3188 * via a CA callback (configured through
3189 * `mbedtls_ssl_conf_ca_cb()`, then the
3190 * CertificateRequest is currently left empty. */
3191
3192 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
3193 if( ssl->handshake->sni_ca_chain != NULL )
3194 crt = ssl->handshake->sni_ca_chain;
3195 else
3196 #endif
3197 crt = ssl->conf->ca_chain;
3198
3199 while( crt != NULL && crt->version != 0 )
3200 {
3201 /* It follows from RFC 5280 A.1 that this length
3202 * can be represented in at most 11 bits. */
3203 dn_size = (uint16_t) crt->subject_raw.len;
3204
3205 if( end < p || (size_t)( end - p ) < 2 + (size_t) dn_size )
3206 {
3207 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) );
3208 break;
3209 }
3210
3211 *p++ = (unsigned char)( dn_size >> 8 );
3212 *p++ = (unsigned char)( dn_size );
3213 memcpy( p, crt->subject_raw.p, dn_size );
3214 p += dn_size;
3215
3216 MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size );
3217
3218 total_dn_size += 2 + dn_size;
3219 crt = crt->next;
3220 }
3221 }
3222
3223 ssl->out_msglen = p - buf;
3224 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3225 ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
3226 ssl->out_msg[4 + ct_len + sa_len] = (unsigned char)( total_dn_size >> 8 );
3227 ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size );
3228
3229 ret = mbedtls_ssl_write_handshake_msg( ssl );
3230
3231 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
3232
3233 return( ret );
3234 }
3235 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
3236
3237 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
3238 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
ssl_get_ecdh_params_from_cert(mbedtls_ssl_context * ssl)3239 static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
3240 {
3241 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3242
3243 if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) )
3244 {
3245 MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
3246 return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
3247 }
3248
3249 if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx,
3250 mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ),
3251 MBEDTLS_ECDH_OURS ) ) != 0 )
3252 {
3253 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret );
3254 return( ret );
3255 }
3256
3257 return( 0 );
3258 }
3259 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
3260 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
3261
3262 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3263 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
ssl_resume_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)3264 static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
3265 size_t *signature_len )
3266 {
3267 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3268 * signature length which will be added in ssl_write_server_key_exchange
3269 * after the call to ssl_prepare_server_key_exchange.
3270 * ssl_write_server_key_exchange also takes care of incrementing
3271 * ssl->out_msglen. */
3272 unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
3273 size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
3274 - sig_start );
3275 int ret = ssl->conf->f_async_resume( ssl,
3276 sig_start, signature_len, sig_max_len );
3277 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3278 {
3279 ssl->handshake->async_in_progress = 0;
3280 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3281 }
3282 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
3283 return( ret );
3284 }
3285 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3286 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3287
3288 /* Prepare the ServerKeyExchange message, up to and including
3289 * calculating the signature if any, but excluding formatting the
3290 * signature and sending the message. */
ssl_prepare_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)3291 static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
3292 size_t *signature_len )
3293 {
3294 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3295 ssl->handshake->ciphersuite_info;
3296
3297 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED)
3298 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3299 unsigned char *dig_signed = NULL;
3300 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3301 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */
3302
3303 (void) ciphersuite_info; /* unused in some configurations */
3304 #if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3305 (void) signature_len;
3306 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3307
3308 ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
3309
3310 /*
3311 *
3312 * Part 1: Provide key exchange parameters for chosen ciphersuite.
3313 *
3314 */
3315
3316 /*
3317 * - ECJPAKE key exchanges
3318 */
3319 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3320 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
3321 {
3322 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3323 size_t len = 0;
3324
3325 ret = mbedtls_ecjpake_write_round_two(
3326 &ssl->handshake->ecjpake_ctx,
3327 ssl->out_msg + ssl->out_msglen,
3328 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
3329 ssl->conf->f_rng, ssl->conf->p_rng );
3330 if( ret != 0 )
3331 {
3332 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret );
3333 return( ret );
3334 }
3335
3336 ssl->out_msglen += len;
3337 }
3338 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
3339
3340 /*
3341 * For (EC)DHE key exchanges with PSK, parameters are prefixed by support
3342 * identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
3343 * we use empty support identity hints here.
3344 **/
3345 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
3346 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
3347 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
3348 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
3349 {
3350 ssl->out_msg[ssl->out_msglen++] = 0x00;
3351 ssl->out_msg[ssl->out_msglen++] = 0x00;
3352 }
3353 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
3354 MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
3355
3356 /*
3357 * - DHE key exchanges
3358 */
3359 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED)
3360 if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
3361 {
3362 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3363 size_t len = 0;
3364
3365 if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
3366 {
3367 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) );
3368 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
3369 }
3370
3371 /*
3372 * Ephemeral DH parameters:
3373 *
3374 * struct {
3375 * opaque dh_p<1..2^16-1>;
3376 * opaque dh_g<1..2^16-1>;
3377 * opaque dh_Ys<1..2^16-1>;
3378 * } ServerDHParams;
3379 */
3380 if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx,
3381 &ssl->conf->dhm_P,
3382 &ssl->conf->dhm_G ) ) != 0 )
3383 {
3384 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret );
3385 return( ret );
3386 }
3387
3388 if( ( ret = mbedtls_dhm_make_params(
3389 &ssl->handshake->dhm_ctx,
3390 (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
3391 ssl->out_msg + ssl->out_msglen, &len,
3392 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3393 {
3394 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret );
3395 return( ret );
3396 }
3397
3398 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3399 dig_signed = ssl->out_msg + ssl->out_msglen;
3400 #endif
3401
3402 ssl->out_msglen += len;
3403
3404 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
3405 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
3406 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
3407 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
3408 }
3409 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */
3410
3411 /*
3412 * - ECDHE key exchanges
3413 */
3414 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED)
3415 if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) )
3416 {
3417 /*
3418 * Ephemeral ECDH parameters:
3419 *
3420 * struct {
3421 * ECParameters curve_params;
3422 * ECPoint public;
3423 * } ServerECDHParams;
3424 */
3425 const mbedtls_ecp_curve_info **curve = NULL;
3426 const mbedtls_ecp_group_id *gid;
3427 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3428 size_t len = 0;
3429
3430 /* Match our preference list against the offered curves */
3431 for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ )
3432 for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
3433 if( (*curve)->grp_id == *gid )
3434 goto curve_matching_done;
3435
3436 curve_matching_done:
3437 if( curve == NULL || *curve == NULL )
3438 {
3439 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
3440 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
3441 }
3442
3443 MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
3444
3445 if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
3446 (*curve)->grp_id ) ) != 0 )
3447 {
3448 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
3449 return( ret );
3450 }
3451
3452 if( ( ret = mbedtls_ecdh_make_params(
3453 &ssl->handshake->ecdh_ctx, &len,
3454 ssl->out_msg + ssl->out_msglen,
3455 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
3456 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3457 {
3458 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
3459 return( ret );
3460 }
3461
3462 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3463 dig_signed = ssl->out_msg + ssl->out_msglen;
3464 #endif
3465
3466 ssl->out_msglen += len;
3467
3468 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3469 MBEDTLS_DEBUG_ECDH_Q );
3470 }
3471 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */
3472
3473 /*
3474 *
3475 * Part 2: For key exchanges involving the server signing the
3476 * exchange parameters, compute and add the signature here.
3477 *
3478 */
3479 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3480 if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
3481 {
3482 size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
3483 size_t hashlen = 0;
3484 unsigned char hash[MBEDTLS_MD_MAX_SIZE];
3485 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3486
3487 /*
3488 * 2.1: Choose hash algorithm:
3489 * A: For TLS 1.2, obey signature-hash-algorithm extension
3490 * to choose appropriate hash.
3491 * B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1
3492 * (RFC 4492, Sec. 5.4)
3493 * C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3)
3494 */
3495
3496 mbedtls_md_type_t md_alg;
3497
3498 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3499 mbedtls_pk_type_t sig_alg =
3500 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
3501 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3502 {
3503 /* A: For TLS 1.2, obey signature-hash-algorithm extension
3504 * (RFC 5246, Sec. 7.4.1.4.1). */
3505 if( sig_alg == MBEDTLS_PK_NONE ||
3506 ( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
3507 sig_alg ) ) == MBEDTLS_MD_NONE )
3508 {
3509 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3510 /* (... because we choose a cipher suite
3511 * only if there is a matching hash.) */
3512 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3513 }
3514 }
3515 else
3516 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3517 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3518 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3519 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
3520 {
3521 /* B: Default hash SHA1 */
3522 md_alg = MBEDTLS_MD_SHA1;
3523 }
3524 else
3525 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3526 MBEDTLS_SSL_PROTO_TLS1_1 */
3527 {
3528 /* C: MD5 + SHA1 */
3529 md_alg = MBEDTLS_MD_NONE;
3530 }
3531
3532 MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %u for signing", (unsigned) md_alg ) );
3533
3534 /*
3535 * 2.2: Compute the hash to be signed
3536 */
3537 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3538 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3539 if( md_alg == MBEDTLS_MD_NONE )
3540 {
3541 hashlen = 36;
3542 ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash,
3543 dig_signed,
3544 dig_signed_len );
3545 if( ret != 0 )
3546 return( ret );
3547 }
3548 else
3549 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3550 MBEDTLS_SSL_PROTO_TLS1_1 */
3551 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3552 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3553 if( md_alg != MBEDTLS_MD_NONE )
3554 {
3555 ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
3556 dig_signed,
3557 dig_signed_len,
3558 md_alg );
3559 if( ret != 0 )
3560 return( ret );
3561 }
3562 else
3563 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
3564 MBEDTLS_SSL_PROTO_TLS1_2 */
3565 {
3566 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3567 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3568 }
3569
3570 MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
3571
3572 /*
3573 * 2.3: Compute and add the signature
3574 */
3575 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3576 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3577 {
3578 /*
3579 * For TLS 1.2, we need to specify signature and hash algorithm
3580 * explicitly through a prefix to the signature.
3581 *
3582 * struct {
3583 * HashAlgorithm hash;
3584 * SignatureAlgorithm signature;
3585 * } SignatureAndHashAlgorithm;
3586 *
3587 * struct {
3588 * SignatureAndHashAlgorithm algorithm;
3589 * opaque signature<0..2^16-1>;
3590 * } DigitallySigned;
3591 *
3592 */
3593
3594 ssl->out_msg[ssl->out_msglen++] =
3595 mbedtls_ssl_hash_from_md_alg( md_alg );
3596 ssl->out_msg[ssl->out_msglen++] =
3597 mbedtls_ssl_sig_from_pk_alg( sig_alg );
3598 }
3599 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3600
3601 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3602 if( ssl->conf->f_async_sign_start != NULL )
3603 {
3604 ret = ssl->conf->f_async_sign_start( ssl,
3605 mbedtls_ssl_own_cert( ssl ),
3606 md_alg, hash, hashlen );
3607 switch( ret )
3608 {
3609 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3610 /* act as if f_async_sign was null */
3611 break;
3612 case 0:
3613 ssl->handshake->async_in_progress = 1;
3614 return( ssl_resume_server_key_exchange( ssl, signature_len ) );
3615 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3616 ssl->handshake->async_in_progress = 1;
3617 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3618 default:
3619 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret );
3620 return( ret );
3621 }
3622 }
3623 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3624
3625 if( mbedtls_ssl_own_key( ssl ) == NULL )
3626 {
3627 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) );
3628 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3629 }
3630
3631 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3632 * signature length which will be added in ssl_write_server_key_exchange
3633 * after the call to ssl_prepare_server_key_exchange.
3634 * ssl_write_server_key_exchange also takes care of incrementing
3635 * ssl->out_msglen. */
3636 if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ),
3637 md_alg, hash, hashlen,
3638 ssl->out_msg + ssl->out_msglen + 2,
3639 signature_len,
3640 ssl->conf->f_rng,
3641 ssl->conf->p_rng ) ) != 0 )
3642 {
3643 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret );
3644 return( ret );
3645 }
3646 }
3647 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3648
3649 return( 0 );
3650 }
3651
3652 /* Prepare the ServerKeyExchange message and send it. For ciphersuites
3653 * that do not include a ServerKeyExchange message, do nothing. Either
3654 * way, if successful, move on to the next step in the SSL state
3655 * machine. */
ssl_write_server_key_exchange(mbedtls_ssl_context * ssl)3656 static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
3657 {
3658 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3659 size_t signature_len = 0;
3660 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3661 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3662 ssl->handshake->ciphersuite_info;
3663 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3664
3665 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
3666
3667 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3668 /* Extract static ECDH parameters and abort if ServerKeyExchange
3669 * is not needed. */
3670 if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) )
3671 {
3672 /* For suites involving ECDH, extract DH parameters
3673 * from certificate at this point. */
3674 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED)
3675 if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) )
3676 {
3677 ssl_get_ecdh_params_from_cert( ssl );
3678 }
3679 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */
3680
3681 /* Key exchanges not involving ephemeral keys don't use
3682 * ServerKeyExchange, so end here. */
3683 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
3684 ssl->state++;
3685 return( 0 );
3686 }
3687 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3688
3689 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3690 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3691 /* If we have already prepared the message and there is an ongoing
3692 * signature operation, resume signing. */
3693 if( ssl->handshake->async_in_progress != 0 )
3694 {
3695 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) );
3696 ret = ssl_resume_server_key_exchange( ssl, &signature_len );
3697 }
3698 else
3699 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3700 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3701 {
3702 /* ServerKeyExchange is needed. Prepare the message. */
3703 ret = ssl_prepare_server_key_exchange( ssl, &signature_len );
3704 }
3705
3706 if( ret != 0 )
3707 {
3708 /* If we're starting to write a new message, set ssl->out_msglen
3709 * to 0. But if we're resuming after an asynchronous message,
3710 * out_msglen is the amount of data written so far and mst be
3711 * preserved. */
3712 if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3713 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) );
3714 else
3715 ssl->out_msglen = 0;
3716 return( ret );
3717 }
3718
3719 /* If there is a signature, write its length.
3720 * ssl_prepare_server_key_exchange already wrote the signature
3721 * itself at its proper place in the output buffer. */
3722 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3723 if( signature_len != 0 )
3724 {
3725 ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len >> 8 );
3726 ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len );
3727
3728 MBEDTLS_SSL_DEBUG_BUF( 3, "my signature",
3729 ssl->out_msg + ssl->out_msglen,
3730 signature_len );
3731
3732 /* Skip over the already-written signature */
3733 ssl->out_msglen += signature_len;
3734 }
3735 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3736
3737 /* Add header and send. */
3738 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3739 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
3740
3741 ssl->state++;
3742
3743 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3744 {
3745 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3746 return( ret );
3747 }
3748
3749 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
3750 return( 0 );
3751 }
3752
ssl_write_server_hello_done(mbedtls_ssl_context * ssl)3753 static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
3754 {
3755 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3756
3757 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
3758
3759 ssl->out_msglen = 4;
3760 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3761 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
3762
3763 ssl->state++;
3764
3765 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3766 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
3767 mbedtls_ssl_send_flight_completed( ssl );
3768 #endif
3769
3770 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3771 {
3772 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3773 return( ret );
3774 }
3775
3776 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3777 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
3778 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
3779 {
3780 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
3781 return( ret );
3782 }
3783 #endif /* MBEDTLS_SSL_PROTO_DTLS */
3784
3785 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
3786
3787 return( 0 );
3788 }
3789
3790 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
3791 defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
ssl_parse_client_dh_public(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3792 static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p,
3793 const unsigned char *end )
3794 {
3795 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3796 size_t n;
3797
3798 /*
3799 * Receive G^Y mod P, premaster = (G^Y)^X mod P
3800 */
3801 if( *p + 2 > end )
3802 {
3803 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3804 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3805 }
3806
3807 n = ( (*p)[0] << 8 ) | (*p)[1];
3808 *p += 2;
3809
3810 if( *p + n > end )
3811 {
3812 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3813 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3814 }
3815
3816 if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 )
3817 {
3818 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret );
3819 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
3820 }
3821
3822 *p += n;
3823
3824 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
3825
3826 return( ret );
3827 }
3828 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
3829 MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3830
3831 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3832 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3833
3834 #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)3835 static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl,
3836 unsigned char *peer_pms,
3837 size_t *peer_pmslen,
3838 size_t peer_pmssize )
3839 {
3840 int ret = ssl->conf->f_async_resume( ssl,
3841 peer_pms, peer_pmslen, peer_pmssize );
3842 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3843 {
3844 ssl->handshake->async_in_progress = 0;
3845 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3846 }
3847 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret );
3848 return( ret );
3849 }
3850 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3851
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)3852 static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl,
3853 const unsigned char *p,
3854 const unsigned char *end,
3855 unsigned char *peer_pms,
3856 size_t *peer_pmslen,
3857 size_t peer_pmssize )
3858 {
3859 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3860 mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl );
3861 mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk;
3862 size_t len = mbedtls_pk_get_len( public_key );
3863
3864 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3865 /* If we have already started decoding the message and there is an ongoing
3866 * decryption operation, resume signing. */
3867 if( ssl->handshake->async_in_progress != 0 )
3868 {
3869 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) );
3870 return( ssl_resume_decrypt_pms( ssl,
3871 peer_pms, peer_pmslen, peer_pmssize ) );
3872 }
3873 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3874
3875 /*
3876 * Prepare to decrypt the premaster using own private RSA key
3877 */
3878 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3879 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3880 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
3881 {
3882 if ( p + 2 > end ) {
3883 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3884 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3885 }
3886 if( *p++ != ( ( len >> 8 ) & 0xFF ) ||
3887 *p++ != ( ( len ) & 0xFF ) )
3888 {
3889 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3890 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3891 }
3892 }
3893 #endif
3894
3895 if( p + len != end )
3896 {
3897 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3898 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3899 }
3900
3901 /*
3902 * Decrypt the premaster secret
3903 */
3904 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3905 if( ssl->conf->f_async_decrypt_start != NULL )
3906 {
3907 ret = ssl->conf->f_async_decrypt_start( ssl,
3908 mbedtls_ssl_own_cert( ssl ),
3909 p, len );
3910 switch( ret )
3911 {
3912 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3913 /* act as if f_async_decrypt_start was null */
3914 break;
3915 case 0:
3916 ssl->handshake->async_in_progress = 1;
3917 return( ssl_resume_decrypt_pms( ssl,
3918 peer_pms,
3919 peer_pmslen,
3920 peer_pmssize ) );
3921 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3922 ssl->handshake->async_in_progress = 1;
3923 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3924 default:
3925 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret );
3926 return( ret );
3927 }
3928 }
3929 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3930
3931 if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) )
3932 {
3933 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
3934 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3935 }
3936
3937 ret = mbedtls_pk_decrypt( private_key, p, len,
3938 peer_pms, peer_pmslen, peer_pmssize,
3939 ssl->conf->f_rng, ssl->conf->p_rng );
3940 return( ret );
3941 }
3942
ssl_parse_encrypted_pms(mbedtls_ssl_context * ssl,const unsigned char * p,const unsigned char * end,size_t pms_offset)3943 static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
3944 const unsigned char *p,
3945 const unsigned char *end,
3946 size_t pms_offset )
3947 {
3948 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3949 unsigned char *pms = ssl->handshake->premaster + pms_offset;
3950 unsigned char ver[2];
3951 unsigned char fake_pms[48], peer_pms[48];
3952 unsigned char mask;
3953 size_t i, peer_pmslen;
3954 unsigned int diff;
3955
3956 /* In case of a failure in decryption, the decryption may write less than
3957 * 2 bytes of output, but we always read the first two bytes. It doesn't
3958 * matter in the end because diff will be nonzero in that case due to
3959 * ret being nonzero, and we only care whether diff is 0.
3960 * But do initialize peer_pms and peer_pmslen for robustness anyway. This
3961 * also makes memory analyzers happy (don't access uninitialized memory,
3962 * even if it's an unsigned char). */
3963 peer_pms[0] = peer_pms[1] = ~0;
3964 peer_pmslen = 0;
3965
3966 ret = ssl_decrypt_encrypted_pms( ssl, p, end,
3967 peer_pms,
3968 &peer_pmslen,
3969 sizeof( peer_pms ) );
3970
3971 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3972 if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3973 return( ret );
3974 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3975
3976 mbedtls_ssl_write_version( ssl->handshake->max_major_ver,
3977 ssl->handshake->max_minor_ver,
3978 ssl->conf->transport, ver );
3979
3980 /* Avoid data-dependent branches while checking for invalid
3981 * padding, to protect against timing-based Bleichenbacher-type
3982 * attacks. */
3983 diff = (unsigned int) ret;
3984 diff |= peer_pmslen ^ 48;
3985 diff |= peer_pms[0] ^ ver[0];
3986 diff |= peer_pms[1] ^ ver[1];
3987
3988 /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
3989 /* MSVC has a warning about unary minus on unsigned, but this is
3990 * well-defined and precisely what we want to do here */
3991 #if defined(_MSC_VER)
3992 #pragma warning( push )
3993 #pragma warning( disable : 4146 )
3994 #endif
3995 mask = - ( ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ) );
3996 #if defined(_MSC_VER)
3997 #pragma warning( pop )
3998 #endif
3999
4000 /*
4001 * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
4002 * must not cause the connection to end immediately; instead, send a
4003 * bad_record_mac later in the handshake.
4004 * To protect against timing-based variants of the attack, we must
4005 * not have any branch that depends on whether the decryption was
4006 * successful. In particular, always generate the fake premaster secret,
4007 * regardless of whether it will ultimately influence the output or not.
4008 */
4009 ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) );
4010 if( ret != 0 )
4011 {
4012 /* It's ok to abort on an RNG failure, since this does not reveal
4013 * anything about the RSA decryption. */
4014 return( ret );
4015 }
4016
4017 #if defined(MBEDTLS_SSL_DEBUG_ALL)
4018 if( diff != 0 )
4019 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4020 #endif
4021
4022 if( sizeof( ssl->handshake->premaster ) < pms_offset ||
4023 sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
4024 {
4025 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4026 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4027 }
4028 ssl->handshake->pmslen = 48;
4029
4030 /* Set pms to either the true or the fake PMS, without
4031 * data-dependent branches. */
4032 for( i = 0; i < ssl->handshake->pmslen; i++ )
4033 pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
4034
4035 return( 0 );
4036 }
4037 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
4038 MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
4039
4040 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
ssl_parse_client_psk_identity(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)4041 static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p,
4042 const unsigned char *end )
4043 {
4044 int ret = 0;
4045 uint16_t n;
4046
4047 if( ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
4048 {
4049 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
4050 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
4051 }
4052
4053 /*
4054 * Receive client pre-shared key identity name
4055 */
4056 if( end - *p < 2 )
4057 {
4058 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4059 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4060 }
4061
4062 n = ( (*p)[0] << 8 ) | (*p)[1];
4063 *p += 2;
4064
4065 if( n == 0 || n > end - *p )
4066 {
4067 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4068 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4069 }
4070
4071 if( ssl->conf->f_psk != NULL )
4072 {
4073 if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 )
4074 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
4075 }
4076 else
4077 {
4078 /* Identity is not a big secret since clients send it in the clear,
4079 * but treat it carefully anyway, just in case */
4080 if( n != ssl->conf->psk_identity_len ||
4081 mbedtls_ssl_safer_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
4082 {
4083 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
4084 }
4085 }
4086
4087 if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
4088 {
4089 MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
4090 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
4091 MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
4092 return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
4093 }
4094
4095 *p += n;
4096
4097 return( 0 );
4098 }
4099 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
4100
ssl_parse_client_key_exchange(mbedtls_ssl_context * ssl)4101 static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
4102 {
4103 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4104 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
4105 unsigned char *p, *end;
4106
4107 ciphersuite_info = ssl->handshake->ciphersuite_info;
4108
4109 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
4110
4111 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
4112 ( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
4113 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
4114 if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
4115 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) &&
4116 ( ssl->handshake->async_in_progress != 0 ) )
4117 {
4118 /* We've already read a record and there is an asynchronous
4119 * operation in progress to decrypt it. So skip reading the
4120 * record. */
4121 MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) );
4122 }
4123 else
4124 #endif
4125 if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
4126 {
4127 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
4128 return( ret );
4129 }
4130
4131 p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
4132 end = ssl->in_msg + ssl->in_hslen;
4133
4134 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
4135 {
4136 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4137 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4138 }
4139
4140 if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
4141 {
4142 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4143 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4144 }
4145
4146 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
4147 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
4148 {
4149 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
4150 {
4151 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
4152 return( ret );
4153 }
4154
4155 if( p != end )
4156 {
4157 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4158 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4159 }
4160
4161 if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
4162 ssl->handshake->premaster,
4163 MBEDTLS_PREMASTER_SIZE,
4164 &ssl->handshake->pmslen,
4165 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
4166 {
4167 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
4168 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
4169 }
4170
4171 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
4172 }
4173 else
4174 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
4175 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
4176 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
4177 defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
4178 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
4179 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
4180 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
4181 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
4182 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
4183 {
4184 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
4185 p, end - p) ) != 0 )
4186 {
4187 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
4188 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
4189 }
4190
4191 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4192 MBEDTLS_DEBUG_ECDH_QP );
4193
4194 if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
4195 &ssl->handshake->pmslen,
4196 ssl->handshake->premaster,
4197 MBEDTLS_MPI_MAX_SIZE,
4198 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
4199 {
4200 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
4201 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
4202 }
4203
4204 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4205 MBEDTLS_DEBUG_ECDH_Z );
4206 }
4207 else
4208 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
4209 MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
4210 MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
4211 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
4212 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
4213 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
4214 {
4215 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4216 {
4217 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4218 return( ret );
4219 }
4220
4221 if( p != end )
4222 {
4223 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4224 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4225 }
4226
4227 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4228 /* For opaque PSKs, we perform the PSK-to-MS derivation atomatically
4229 * and skip the intermediate PMS. */
4230 if( ssl_use_opaque_psk( ssl ) == 1 )
4231 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skip PMS generation for opaque PSK" ) );
4232 else
4233 #endif /* MBEDTLS_USE_PSA_CRYPTO */
4234 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4235 ciphersuite_info->key_exchange ) ) != 0 )
4236 {
4237 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4238 return( ret );
4239 }
4240 }
4241 else
4242 #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
4243 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
4244 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
4245 {
4246 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
4247 if ( ssl->handshake->async_in_progress != 0 )
4248 {
4249 /* There is an asynchronous operation in progress to
4250 * decrypt the encrypted premaster secret, so skip
4251 * directly to resuming this operation. */
4252 MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) );
4253 /* Update p to skip the PSK identity. ssl_parse_encrypted_pms
4254 * won't actually use it, but maintain p anyway for robustness. */
4255 p += ssl->conf->psk_identity_len + 2;
4256 }
4257 else
4258 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
4259 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4260 {
4261 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4262 return( ret );
4263 }
4264
4265 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4266 /* Opaque PSKs are currently only supported for PSK-only. */
4267 if( ssl_use_opaque_psk( ssl ) == 1 )
4268 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4269 #endif
4270
4271 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
4272 {
4273 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
4274 return( ret );
4275 }
4276
4277 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4278 ciphersuite_info->key_exchange ) ) != 0 )
4279 {
4280 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4281 return( ret );
4282 }
4283 }
4284 else
4285 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
4286 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
4287 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
4288 {
4289 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4290 {
4291 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4292 return( ret );
4293 }
4294 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
4295 {
4296 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
4297 return( ret );
4298 }
4299
4300 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4301 /* Opaque PSKs are currently only supported for PSK-only. */
4302 if( ssl_use_opaque_psk( ssl ) == 1 )
4303 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4304 #endif
4305
4306 if( p != end )
4307 {
4308 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4309 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4310 }
4311
4312 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4313 ciphersuite_info->key_exchange ) ) != 0 )
4314 {
4315 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4316 return( ret );
4317 }
4318 }
4319 else
4320 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
4321 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
4322 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
4323 {
4324 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4325 {
4326 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4327 return( ret );
4328 }
4329
4330 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
4331 p, end - p ) ) != 0 )
4332 {
4333 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
4334 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
4335 }
4336
4337 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4338 /* Opaque PSKs are currently only supported for PSK-only. */
4339 if( ssl_use_opaque_psk( ssl ) == 1 )
4340 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4341 #endif
4342
4343 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4344 MBEDTLS_DEBUG_ECDH_QP );
4345
4346 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4347 ciphersuite_info->key_exchange ) ) != 0 )
4348 {
4349 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4350 return( ret );
4351 }
4352 }
4353 else
4354 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
4355 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
4356 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
4357 {
4358 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 )
4359 {
4360 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
4361 return( ret );
4362 }
4363 }
4364 else
4365 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
4366 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
4367 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
4368 {
4369 ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx,
4370 p, end - p );
4371 if( ret != 0 )
4372 {
4373 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
4374 return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
4375 }
4376
4377 ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
4378 ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
4379 ssl->conf->f_rng, ssl->conf->p_rng );
4380 if( ret != 0 )
4381 {
4382 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
4383 return( ret );
4384 }
4385 }
4386 else
4387 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
4388 {
4389 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4390 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4391 }
4392
4393 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
4394 {
4395 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
4396 return( ret );
4397 }
4398
4399 ssl->state++;
4400
4401 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
4402
4403 return( 0 );
4404 }
4405
4406 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4407 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4408 {
4409 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4410 ssl->handshake->ciphersuite_info;
4411
4412 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4413
4414 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4415 {
4416 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4417 ssl->state++;
4418 return( 0 );
4419 }
4420
4421 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4422 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4423 }
4424 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4425 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4426 {
4427 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
4428 size_t i, sig_len;
4429 unsigned char hash[48];
4430 unsigned char *hash_start = hash;
4431 size_t hashlen;
4432 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4433 mbedtls_pk_type_t pk_alg;
4434 #endif
4435 mbedtls_md_type_t md_alg;
4436 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4437 ssl->handshake->ciphersuite_info;
4438 mbedtls_pk_context * peer_pk;
4439
4440 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4441
4442 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4443 {
4444 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4445 ssl->state++;
4446 return( 0 );
4447 }
4448
4449 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4450 if( ssl->session_negotiate->peer_cert == NULL )
4451 {
4452 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4453 ssl->state++;
4454 return( 0 );
4455 }
4456 #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4457 if( ssl->session_negotiate->peer_cert_digest == NULL )
4458 {
4459 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4460 ssl->state++;
4461 return( 0 );
4462 }
4463 #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4464
4465 /* Read the message without adding it to the checksum */
4466 ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
4467 if( 0 != ret )
4468 {
4469 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
4470 return( ret );
4471 }
4472
4473 ssl->state++;
4474
4475 /* Process the message contents */
4476 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
4477 ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY )
4478 {
4479 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4480 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4481 }
4482
4483 i = mbedtls_ssl_hs_hdr_len( ssl );
4484
4485 #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4486 peer_pk = &ssl->handshake->peer_pubkey;
4487 #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4488 if( ssl->session_negotiate->peer_cert == NULL )
4489 {
4490 /* Should never happen */
4491 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4492 }
4493 peer_pk = &ssl->session_negotiate->peer_cert->pk;
4494 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4495
4496 /*
4497 * struct {
4498 * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
4499 * opaque signature<0..2^16-1>;
4500 * } DigitallySigned;
4501 */
4502 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
4503 defined(MBEDTLS_SSL_PROTO_TLS1_1)
4504 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 )
4505 {
4506 md_alg = MBEDTLS_MD_NONE;
4507 hashlen = 36;
4508
4509 /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
4510 if( mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECDSA ) )
4511 {
4512 hash_start += 16;
4513 hashlen -= 16;
4514 md_alg = MBEDTLS_MD_SHA1;
4515 }
4516 }
4517 else
4518 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 ||
4519 MBEDTLS_SSL_PROTO_TLS1_1 */
4520 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4521 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
4522 {
4523 if( i + 2 > ssl->in_hslen )
4524 {
4525 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4526 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4527 }
4528
4529 /*
4530 * Hash
4531 */
4532 md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] );
4533
4534 if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) )
4535 {
4536 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4537 " for verify message" ) );
4538 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4539 }
4540
4541 #if !defined(MBEDTLS_MD_SHA1)
4542 if( MBEDTLS_MD_SHA1 == md_alg )
4543 hash_start += 16;
4544 #endif
4545
4546 /* Info from md_alg will be used instead */
4547 hashlen = 0;
4548
4549 i++;
4550
4551 /*
4552 * Signature
4553 */
4554 if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) )
4555 == MBEDTLS_PK_NONE )
4556 {
4557 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4558 " for verify message" ) );
4559 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4560 }
4561
4562 /*
4563 * Check the certificate's key type matches the signature alg
4564 */
4565 if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
4566 {
4567 MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
4568 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4569 }
4570
4571 i++;
4572 }
4573 else
4574 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
4575 {
4576 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4577 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4578 }
4579
4580 if( i + 2 > ssl->in_hslen )
4581 {
4582 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4583 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4584 }
4585
4586 sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
4587 i += 2;
4588
4589 if( i + sig_len != ssl->in_hslen )
4590 {
4591 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4592 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4593 }
4594
4595 /* Calculate hash and verify signature */
4596 {
4597 size_t dummy_hlen;
4598 ssl->handshake->calc_verify( ssl, hash, &dummy_hlen );
4599 }
4600
4601 if( ( ret = mbedtls_pk_verify( peer_pk,
4602 md_alg, hash_start, hashlen,
4603 ssl->in_msg + i, sig_len ) ) != 0 )
4604 {
4605 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
4606 return( ret );
4607 }
4608
4609 mbedtls_ssl_update_handshake_status( ssl );
4610
4611 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
4612
4613 return( ret );
4614 }
4615 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
4616
4617 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_new_session_ticket(mbedtls_ssl_context * ssl)4618 static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
4619 {
4620 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4621 size_t tlen;
4622 uint32_t lifetime;
4623
4624 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
4625
4626 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
4627 ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
4628
4629 /*
4630 * struct {
4631 * uint32 ticket_lifetime_hint;
4632 * opaque ticket<0..2^16-1>;
4633 * } NewSessionTicket;
4634 *
4635 * 4 . 7 ticket_lifetime_hint (0 = unspecified)
4636 * 8 . 9 ticket_len (n)
4637 * 10 . 9+n ticket content
4638 */
4639
4640 if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
4641 ssl->session_negotiate,
4642 ssl->out_msg + 10,
4643 ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
4644 &tlen, &lifetime ) ) != 0 )
4645 {
4646 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
4647 tlen = 0;
4648 }
4649
4650 ssl->out_msg[4] = ( lifetime >> 24 ) & 0xFF;
4651 ssl->out_msg[5] = ( lifetime >> 16 ) & 0xFF;
4652 ssl->out_msg[6] = ( lifetime >> 8 ) & 0xFF;
4653 ssl->out_msg[7] = ( lifetime ) & 0xFF;
4654
4655 ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF );
4656 ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF );
4657
4658 ssl->out_msglen = 10 + tlen;
4659
4660 /*
4661 * Morally equivalent to updating ssl->state, but NewSessionTicket and
4662 * ChangeCipherSpec share the same state.
4663 */
4664 ssl->handshake->new_session_ticket = 0;
4665
4666 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
4667 {
4668 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
4669 return( ret );
4670 }
4671
4672 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
4673
4674 return( 0 );
4675 }
4676 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
4677
4678 /*
4679 * SSL handshake -- server side -- single step
4680 */
mbedtls_ssl_handshake_server_step(mbedtls_ssl_context * ssl)4681 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
4682 {
4683 int ret = 0;
4684
4685 if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
4686 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4687
4688 MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
4689
4690 if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
4691 return( ret );
4692
4693 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4694 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
4695 ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
4696 {
4697 if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
4698 return( ret );
4699 }
4700 #endif /* MBEDTLS_SSL_PROTO_DTLS */
4701
4702 switch( ssl->state )
4703 {
4704 case MBEDTLS_SSL_HELLO_REQUEST:
4705 ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
4706 break;
4707
4708 /*
4709 * <== ClientHello
4710 */
4711 case MBEDTLS_SSL_CLIENT_HELLO:
4712 ret = ssl_parse_client_hello( ssl );
4713 break;
4714
4715 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4716 case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
4717 return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
4718 #endif
4719
4720 /*
4721 * ==> ServerHello
4722 * Certificate
4723 * ( ServerKeyExchange )
4724 * ( CertificateRequest )
4725 * ServerHelloDone
4726 */
4727 case MBEDTLS_SSL_SERVER_HELLO:
4728 ret = ssl_write_server_hello( ssl );
4729 break;
4730
4731 case MBEDTLS_SSL_SERVER_CERTIFICATE:
4732 ret = mbedtls_ssl_write_certificate( ssl );
4733 break;
4734
4735 case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
4736 ret = ssl_write_server_key_exchange( ssl );
4737 break;
4738
4739 case MBEDTLS_SSL_CERTIFICATE_REQUEST:
4740 ret = ssl_write_certificate_request( ssl );
4741 break;
4742
4743 case MBEDTLS_SSL_SERVER_HELLO_DONE:
4744 ret = ssl_write_server_hello_done( ssl );
4745 break;
4746
4747 /*
4748 * <== ( Certificate/Alert )
4749 * ClientKeyExchange
4750 * ( CertificateVerify )
4751 * ChangeCipherSpec
4752 * Finished
4753 */
4754 case MBEDTLS_SSL_CLIENT_CERTIFICATE:
4755 ret = mbedtls_ssl_parse_certificate( ssl );
4756 break;
4757
4758 case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
4759 ret = ssl_parse_client_key_exchange( ssl );
4760 break;
4761
4762 case MBEDTLS_SSL_CERTIFICATE_VERIFY:
4763 ret = ssl_parse_certificate_verify( ssl );
4764 break;
4765
4766 case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
4767 ret = mbedtls_ssl_parse_change_cipher_spec( ssl );
4768 break;
4769
4770 case MBEDTLS_SSL_CLIENT_FINISHED:
4771 ret = mbedtls_ssl_parse_finished( ssl );
4772 break;
4773
4774 /*
4775 * ==> ( NewSessionTicket )
4776 * ChangeCipherSpec
4777 * Finished
4778 */
4779 case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
4780 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
4781 if( ssl->handshake->new_session_ticket != 0 )
4782 ret = ssl_write_new_session_ticket( ssl );
4783 else
4784 #endif
4785 ret = mbedtls_ssl_write_change_cipher_spec( ssl );
4786 break;
4787
4788 case MBEDTLS_SSL_SERVER_FINISHED:
4789 ret = mbedtls_ssl_write_finished( ssl );
4790 break;
4791
4792 case MBEDTLS_SSL_FLUSH_BUFFERS:
4793 MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
4794 ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
4795 break;
4796
4797 case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
4798 mbedtls_ssl_handshake_wrapup( ssl );
4799 break;
4800
4801 default:
4802 MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
4803 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4804 }
4805
4806 return( ret );
4807 }
4808 #endif /* MBEDTLS_SSL_SRV_C */
4809