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 #include "constant_time_internal.h"
38 #include "mbedtls/constant_time.h"
39
40 #include <string.h>
41
42 #if defined(MBEDTLS_ECP_C)
43 #include "mbedtls/ecp.h"
44 #endif
45
46 #if defined(MBEDTLS_HAVE_TIME)
47 #include "mbedtls/platform_time.h"
48 #endif
49
50 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context * ssl,const unsigned char * info,size_t ilen)51 int mbedtls_ssl_set_client_transport_id( mbedtls_ssl_context *ssl,
52 const unsigned char *info,
53 size_t ilen )
54 {
55 if( ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER )
56 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
57
58 mbedtls_free( ssl->cli_id );
59
60 if( ( ssl->cli_id = mbedtls_calloc( 1, ilen ) ) == NULL )
61 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
62
63 memcpy( ssl->cli_id, info, ilen );
64 ssl->cli_id_len = ilen;
65
66 return( 0 );
67 }
68
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)69 void mbedtls_ssl_conf_dtls_cookies( mbedtls_ssl_config *conf,
70 mbedtls_ssl_cookie_write_t *f_cookie_write,
71 mbedtls_ssl_cookie_check_t *f_cookie_check,
72 void *p_cookie )
73 {
74 conf->f_cookie_write = f_cookie_write;
75 conf->f_cookie_check = f_cookie_check;
76 conf->p_cookie = p_cookie;
77 }
78 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
79
80 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
ssl_parse_servername_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)81 static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
82 const unsigned char *buf,
83 size_t len )
84 {
85 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
86 size_t servername_list_size, hostname_len;
87 const unsigned char *p;
88
89 MBEDTLS_SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) );
90
91 if( len < 2 )
92 {
93 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
94 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
95 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
96 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
97 }
98 servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
99 if( servername_list_size + 2 != len )
100 {
101 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
102 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
103 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
104 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
105 }
106
107 p = buf + 2;
108 while( servername_list_size > 2 )
109 {
110 hostname_len = ( ( p[1] << 8 ) | p[2] );
111 if( hostname_len + 3 > servername_list_size )
112 {
113 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
114 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
115 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
116 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
117 }
118
119 if( p[0] == MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME )
120 {
121 ret = ssl->conf->f_sni( ssl->conf->p_sni,
122 ssl, p + 3, hostname_len );
123 if( ret != 0 )
124 {
125 MBEDTLS_SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret );
126 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
127 MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME );
128 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
129 }
130 return( 0 );
131 }
132
133 servername_list_size -= hostname_len + 3;
134 p += hostname_len + 3;
135 }
136
137 if( servername_list_size != 0 )
138 {
139 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
140 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
141 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
142 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
143 }
144
145 return( 0 );
146 }
147 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
148
149 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
ssl_conf_has_psk_or_cb(mbedtls_ssl_config const * conf)150 static int ssl_conf_has_psk_or_cb( mbedtls_ssl_config const *conf )
151 {
152 if( conf->f_psk != NULL )
153 return( 1 );
154
155 if( conf->psk_identity_len == 0 || conf->psk_identity == NULL )
156 return( 0 );
157
158 if( conf->psk != NULL && conf->psk_len != 0 )
159 return( 1 );
160
161 #if defined(MBEDTLS_USE_PSA_CRYPTO)
162 if( ! mbedtls_svc_key_id_is_null( conf->psk_opaque ) )
163 return( 1 );
164 #endif /* MBEDTLS_USE_PSA_CRYPTO */
165
166 return( 0 );
167 }
168
169 #if defined(MBEDTLS_USE_PSA_CRYPTO)
ssl_use_opaque_psk(mbedtls_ssl_context const * ssl)170 static int ssl_use_opaque_psk( mbedtls_ssl_context const *ssl )
171 {
172 if( ssl->conf->f_psk != NULL )
173 {
174 /* If we've used a callback to select the PSK,
175 * the static configuration is irrelevant. */
176
177 if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) )
178 return( 1 );
179
180 return( 0 );
181 }
182
183 if( ! mbedtls_svc_key_id_is_null( ssl->conf->psk_opaque ) )
184 return( 1 );
185
186 return( 0 );
187 }
188 #endif /* MBEDTLS_USE_PSA_CRYPTO */
189 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
190
ssl_parse_renegotiation_info(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)191 static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
192 const unsigned char *buf,
193 size_t len )
194 {
195 #if defined(MBEDTLS_SSL_RENEGOTIATION)
196 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
197 {
198 /* Check verify-data in constant-time. The length OTOH is no secret */
199 if( len != 1 + ssl->verify_data_len ||
200 buf[0] != ssl->verify_data_len ||
201 mbedtls_ct_memcmp( buf + 1, ssl->peer_verify_data,
202 ssl->verify_data_len ) != 0 )
203 {
204 MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
205 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
206 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
207 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
208 }
209 }
210 else
211 #endif /* MBEDTLS_SSL_RENEGOTIATION */
212 {
213 if( len != 1 || buf[0] != 0x0 )
214 {
215 MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
216 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
217 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
218 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
219 }
220
221 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
222 }
223
224 return( 0 );
225 }
226
227 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
228 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
229
230 /*
231 * Status of the implementation of signature-algorithms extension:
232 *
233 * Currently, we are only considering the signature-algorithm extension
234 * to pick a ciphersuite which allows us to send the ServerKeyExchange
235 * message with a signature-hash combination that the user allows.
236 *
237 * We do *not* check whether all certificates in our certificate
238 * chain are signed with an allowed signature-hash pair.
239 * This needs to be done at a later stage.
240 *
241 */
ssl_parse_signature_algorithms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)242 static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
243 const unsigned char *buf,
244 size_t len )
245 {
246 size_t sig_alg_list_size;
247
248 const unsigned char *p;
249 const unsigned char *end = buf + len;
250
251 mbedtls_md_type_t md_cur;
252 mbedtls_pk_type_t sig_cur;
253
254 if ( len < 2 ) {
255 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
256 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
257 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
258 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
259 }
260 sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
261 if( sig_alg_list_size + 2 != len ||
262 sig_alg_list_size % 2 != 0 )
263 {
264 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
265 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
266 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
267 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
268 }
269
270 /* Currently we only guarantee signing the ServerKeyExchange message according
271 * to the constraints specified in this extension (see above), so it suffices
272 * to remember only one suitable hash for each possible signature algorithm.
273 *
274 * This will change when we also consider certificate signatures,
275 * in which case we will need to remember the whole signature-hash
276 * pair list from the extension.
277 */
278
279 for( p = buf + 2; p < end; p += 2 )
280 {
281 /* Silently ignore unknown signature or hash algorithms. */
282
283 if( ( sig_cur = mbedtls_ssl_pk_alg_from_sig( p[1] ) ) == MBEDTLS_PK_NONE )
284 {
285 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext"
286 " unknown sig alg encoding %d", p[1] ) );
287 continue;
288 }
289
290 /* Check if we support the hash the user proposes */
291 md_cur = mbedtls_ssl_md_alg_from_hash( p[0] );
292 if( md_cur == MBEDTLS_MD_NONE )
293 {
294 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
295 " unknown hash alg encoding %d", p[0] ) );
296 continue;
297 }
298
299 if( mbedtls_ssl_check_sig_hash( ssl, md_cur ) == 0 )
300 {
301 mbedtls_ssl_sig_hash_set_add( &ssl->handshake->hash_algs, sig_cur, md_cur );
302 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
303 " match sig %u and hash %u",
304 (unsigned) sig_cur, (unsigned) md_cur ) );
305 }
306 else
307 {
308 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: "
309 "hash alg %u not supported", (unsigned) md_cur ) );
310 }
311 }
312
313 return( 0 );
314 }
315 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
316 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
317
318 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
319 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_supported_elliptic_curves(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)320 static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
321 const unsigned char *buf,
322 size_t len )
323 {
324 size_t list_size, our_size;
325 const unsigned char *p;
326 const mbedtls_ecp_curve_info *curve_info, **curves;
327
328 if ( len < 2 ) {
329 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
330 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
331 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
332 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
333 }
334 list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
335 if( list_size + 2 != len ||
336 list_size % 2 != 0 )
337 {
338 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
339 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
340 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
341 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
342 }
343
344 /* Should never happen unless client duplicates the extension */
345 if( ssl->handshake->curves != NULL )
346 {
347 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
348 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
349 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
350 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
351 }
352
353 /* Don't allow our peer to make us allocate too much memory,
354 * and leave room for a final 0 */
355 our_size = list_size / 2 + 1;
356 if( our_size > MBEDTLS_ECP_DP_MAX )
357 our_size = MBEDTLS_ECP_DP_MAX;
358
359 if( ( curves = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == NULL )
360 {
361 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
362 MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
363 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
364 }
365
366 ssl->handshake->curves = curves;
367
368 p = buf + 2;
369 while( list_size > 0 && our_size > 1 )
370 {
371 curve_info = mbedtls_ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] );
372
373 if( curve_info != NULL )
374 {
375 *curves++ = curve_info;
376 our_size--;
377 }
378
379 list_size -= 2;
380 p += 2;
381 }
382
383 return( 0 );
384 }
385
ssl_parse_supported_point_formats(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)386 static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl,
387 const unsigned char *buf,
388 size_t len )
389 {
390 size_t list_size;
391 const unsigned char *p;
392
393 if( len == 0 || (size_t)( buf[0] + 1 ) != len )
394 {
395 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
396 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
397 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
398 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
399 }
400 list_size = buf[0];
401
402 p = buf + 1;
403 while( list_size > 0 )
404 {
405 if( p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED ||
406 p[0] == MBEDTLS_ECP_PF_COMPRESSED )
407 {
408 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
409 ssl->handshake->ecdh_ctx.point_format = p[0];
410 #endif
411 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
412 ssl->handshake->ecjpake_ctx.point_format = p[0];
413 #endif
414 MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
415 return( 0 );
416 }
417
418 list_size--;
419 p++;
420 }
421
422 return( 0 );
423 }
424 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
425 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
426
427 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_ecjpake_kkpp(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)428 static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
429 const unsigned char *buf,
430 size_t len )
431 {
432 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
433
434 if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
435 {
436 MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip ecjpake kkpp extension" ) );
437 return( 0 );
438 }
439
440 if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx,
441 buf, len ) ) != 0 )
442 {
443 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
444 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
445 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
446 return( ret );
447 }
448
449 /* Only mark the extension as OK when we're sure it is */
450 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK;
451
452 return( 0 );
453 }
454 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
455
456 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_parse_max_fragment_length_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)457 static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
458 const unsigned char *buf,
459 size_t len )
460 {
461 if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID )
462 {
463 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
464 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
465 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
466 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
467 }
468
469 ssl->session_negotiate->mfl_code = buf[0];
470
471 return( 0 );
472 }
473 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
474
475 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_parse_cid_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)476 static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl,
477 const unsigned char *buf,
478 size_t len )
479 {
480 size_t peer_cid_len;
481
482 /* CID extension only makes sense in DTLS */
483 if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
484 {
485 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
486 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
487 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
488 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
489 }
490
491 /*
492 * Quoting draft-ietf-tls-dtls-connection-id-05
493 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
494 *
495 * struct {
496 * opaque cid<0..2^8-1>;
497 * } ConnectionId;
498 */
499
500 if( len < 1 )
501 {
502 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
503 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
504 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
505 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
506 }
507
508 peer_cid_len = *buf++;
509 len--;
510
511 if( len != peer_cid_len )
512 {
513 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
514 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
515 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
516 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
517 }
518
519 /* Ignore CID if the user has disabled its use. */
520 if( ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED )
521 {
522 /* Leave ssl->handshake->cid_in_use in its default
523 * value of MBEDTLS_SSL_CID_DISABLED. */
524 MBEDTLS_SSL_DEBUG_MSG( 3, ( "Client sent CID extension, but CID disabled" ) );
525 return( 0 );
526 }
527
528 if( peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX )
529 {
530 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
531 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
532 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
533 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
534 }
535
536 ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED;
537 ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len;
538 memcpy( ssl->handshake->peer_cid, buf, peer_cid_len );
539
540 MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use of CID extension negotiated" ) );
541 MBEDTLS_SSL_DEBUG_BUF( 3, "Client CID", buf, peer_cid_len );
542
543 return( 0 );
544 }
545 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
546
547 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_parse_truncated_hmac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)548 static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
549 const unsigned char *buf,
550 size_t len )
551 {
552 if( len != 0 )
553 {
554 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
555 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
556 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
557 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
558 }
559
560 ((void) buf);
561
562 if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED )
563 ssl->session_negotiate->trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED;
564
565 return( 0 );
566 }
567 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
568
569 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_parse_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)570 static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
571 const unsigned char *buf,
572 size_t len )
573 {
574 if( len != 0 )
575 {
576 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
577 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
578 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
579 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
580 }
581
582 ((void) buf);
583
584 if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED &&
585 ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
586 {
587 ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED;
588 }
589
590 return( 0 );
591 }
592 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
593
594 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_parse_extended_ms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)595 static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
596 const unsigned char *buf,
597 size_t len )
598 {
599 if( len != 0 )
600 {
601 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
602 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
603 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
604 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
605 }
606
607 ((void) buf);
608
609 if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED &&
610 ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
611 {
612 ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
613 }
614
615 return( 0 );
616 }
617 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
618
619 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_parse_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t len)620 static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
621 unsigned char *buf,
622 size_t len )
623 {
624 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
625 mbedtls_ssl_session session;
626
627 mbedtls_ssl_session_init( &session );
628
629 if( ssl->conf->f_ticket_parse == NULL ||
630 ssl->conf->f_ticket_write == NULL )
631 {
632 return( 0 );
633 }
634
635 /* Remember the client asked us to send a new ticket */
636 ssl->handshake->new_session_ticket = 1;
637
638 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %" MBEDTLS_PRINTF_SIZET, len ) );
639
640 if( len == 0 )
641 return( 0 );
642
643 #if defined(MBEDTLS_SSL_RENEGOTIATION)
644 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
645 {
646 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
647 return( 0 );
648 }
649 #endif /* MBEDTLS_SSL_RENEGOTIATION */
650
651 /*
652 * Failures are ok: just ignore the ticket and proceed.
653 */
654 if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session,
655 buf, len ) ) != 0 )
656 {
657 mbedtls_ssl_session_free( &session );
658
659 if( ret == MBEDTLS_ERR_SSL_INVALID_MAC )
660 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) );
661 else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED )
662 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) );
663 else
664 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
665
666 return( 0 );
667 }
668
669 /*
670 * Keep the session ID sent by the client, since we MUST send it back to
671 * inform them we're accepting the ticket (RFC 5077 section 3.4)
672 */
673 session.id_len = ssl->session_negotiate->id_len;
674 memcpy( &session.id, ssl->session_negotiate->id, session.id_len );
675
676 mbedtls_ssl_session_free( ssl->session_negotiate );
677 memcpy( ssl->session_negotiate, &session, sizeof( mbedtls_ssl_session ) );
678
679 /* Zeroize instead of free as we copied the content */
680 mbedtls_platform_zeroize( &session, sizeof( mbedtls_ssl_session ) );
681
682 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
683
684 ssl->handshake->resume = 1;
685
686 /* Don't send a new ticket after all, this one is OK */
687 ssl->handshake->new_session_ticket = 0;
688
689 return( 0 );
690 }
691 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
692
693 #if defined(MBEDTLS_SSL_ALPN)
ssl_parse_alpn_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)694 static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
695 const unsigned char *buf, size_t len )
696 {
697 size_t list_len, cur_len, ours_len;
698 const unsigned char *theirs, *start, *end;
699 const char **ours;
700
701 /* If ALPN not configured, just ignore the extension */
702 if( ssl->conf->alpn_list == NULL )
703 return( 0 );
704
705 /*
706 * opaque ProtocolName<1..2^8-1>;
707 *
708 * struct {
709 * ProtocolName protocol_name_list<2..2^16-1>
710 * } ProtocolNameList;
711 */
712
713 /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
714 if( len < 4 )
715 {
716 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
717 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
718 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
719 }
720
721 list_len = ( buf[0] << 8 ) | buf[1];
722 if( list_len != len - 2 )
723 {
724 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
725 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
726 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
727 }
728
729 /*
730 * Validate peer's list (lengths)
731 */
732 start = buf + 2;
733 end = buf + len;
734 for( theirs = start; theirs != end; theirs += cur_len )
735 {
736 cur_len = *theirs++;
737
738 /* Current identifier must fit in list */
739 if( cur_len > (size_t)( end - theirs ) )
740 {
741 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
742 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
743 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
744 }
745
746 /* Empty strings MUST NOT be included */
747 if( cur_len == 0 )
748 {
749 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
750 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
751 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
752 }
753 }
754
755 /*
756 * Use our order of preference
757 */
758 for( ours = ssl->conf->alpn_list; *ours != NULL; ours++ )
759 {
760 ours_len = strlen( *ours );
761 for( theirs = start; theirs != end; theirs += cur_len )
762 {
763 cur_len = *theirs++;
764
765 if( cur_len == ours_len &&
766 memcmp( theirs, *ours, cur_len ) == 0 )
767 {
768 ssl->alpn_chosen = *ours;
769 return( 0 );
770 }
771 }
772 }
773
774 /* If we get there, no match was found */
775 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
776 MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
777 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
778 }
779 #endif /* MBEDTLS_SSL_ALPN */
780
781 #if defined(MBEDTLS_SSL_DTLS_SRTP)
ssl_parse_use_srtp_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)782 static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
783 const unsigned char *buf,
784 size_t len )
785 {
786 mbedtls_ssl_srtp_profile client_protection = MBEDTLS_TLS_SRTP_UNSET;
787 size_t i,j;
788 size_t profile_length;
789 uint16_t mki_length;
790 /*! 2 bytes for profile length and 1 byte for mki len */
791 const size_t size_of_lengths = 3;
792
793 /* If use_srtp is not configured, just ignore the extension */
794 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
795 ( ssl->conf->dtls_srtp_profile_list == NULL ) ||
796 ( ssl->conf->dtls_srtp_profile_list_len == 0 ) )
797 {
798 return( 0 );
799 }
800
801 /* RFC5764 section 4.1.1
802 * uint8 SRTPProtectionProfile[2];
803 *
804 * struct {
805 * SRTPProtectionProfiles SRTPProtectionProfiles;
806 * opaque srtp_mki<0..255>;
807 * } UseSRTPData;
808
809 * SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>;
810 */
811
812 /*
813 * Min length is 5: at least one protection profile(2 bytes)
814 * and length(2 bytes) + srtp_mki length(1 byte)
815 * Check here that we have at least 2 bytes of protection profiles length
816 * and one of srtp_mki length
817 */
818 if( len < size_of_lengths )
819 {
820 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
821 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
822 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
823 }
824
825 ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_TLS_SRTP_UNSET;
826
827 /* first 2 bytes are protection profile length(in bytes) */
828 profile_length = ( buf[0] << 8 ) | buf[1];
829 buf += 2;
830
831 /* The profile length cannot be bigger than input buffer size - lengths fields */
832 if( profile_length > len - size_of_lengths ||
833 profile_length % 2 != 0 ) /* profiles are 2 bytes long, so the length must be even */
834 {
835 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
836 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
837 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
838 }
839 /*
840 * parse the extension list values are defined in
841 * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
842 */
843 for( j = 0; j < profile_length; j += 2 )
844 {
845 uint16_t protection_profile_value = buf[j] << 8 | buf[j + 1];
846 client_protection = mbedtls_ssl_check_srtp_profile_value( protection_profile_value );
847
848 if( client_protection != MBEDTLS_TLS_SRTP_UNSET )
849 {
850 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found srtp profile: %s",
851 mbedtls_ssl_get_srtp_profile_as_string(
852 client_protection ) ) );
853 }
854 else
855 {
856 continue;
857 }
858 /* check if suggested profile is in our list */
859 for( i = 0; i < ssl->conf->dtls_srtp_profile_list_len; i++)
860 {
861 if( client_protection == ssl->conf->dtls_srtp_profile_list[i] )
862 {
863 ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i];
864 MBEDTLS_SSL_DEBUG_MSG( 3, ( "selected srtp profile: %s",
865 mbedtls_ssl_get_srtp_profile_as_string(
866 client_protection ) ) );
867 break;
868 }
869 }
870 if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_TLS_SRTP_UNSET )
871 break;
872 }
873 buf += profile_length; /* buf points to the mki length */
874 mki_length = *buf;
875 buf++;
876
877 if( mki_length > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH ||
878 mki_length + profile_length + size_of_lengths != len )
879 {
880 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
881 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
882 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
883 }
884
885 /* Parse the mki only if present and mki is supported locally */
886 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED &&
887 mki_length > 0 )
888 {
889 ssl->dtls_srtp_info.mki_len = mki_length;
890
891 memcpy( ssl->dtls_srtp_info.mki_value, buf, mki_length );
892
893 MBEDTLS_SSL_DEBUG_BUF( 3, "using mki", ssl->dtls_srtp_info.mki_value,
894 ssl->dtls_srtp_info.mki_len );
895 }
896
897 return( 0 );
898 }
899 #endif /* MBEDTLS_SSL_DTLS_SRTP */
900
901 /*
902 * Auxiliary functions for ServerHello parsing and related actions
903 */
904
905 #if defined(MBEDTLS_X509_CRT_PARSE_C)
906 /*
907 * Return 0 if the given key uses one of the acceptable curves, -1 otherwise
908 */
909 #if defined(MBEDTLS_ECDSA_C)
ssl_check_key_curve(mbedtls_pk_context * pk,const mbedtls_ecp_curve_info ** curves)910 static int ssl_check_key_curve( mbedtls_pk_context *pk,
911 const mbedtls_ecp_curve_info **curves )
912 {
913 const mbedtls_ecp_curve_info **crv = curves;
914 mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id;
915
916 while( *crv != NULL )
917 {
918 if( (*crv)->grp_id == grp_id )
919 return( 0 );
920 crv++;
921 }
922
923 return( -1 );
924 }
925 #endif /* MBEDTLS_ECDSA_C */
926
927 /*
928 * Try picking a certificate for this ciphersuite,
929 * return 0 on success and -1 on failure.
930 */
ssl_pick_cert(mbedtls_ssl_context * ssl,const mbedtls_ssl_ciphersuite_t * ciphersuite_info)931 static int ssl_pick_cert( mbedtls_ssl_context *ssl,
932 const mbedtls_ssl_ciphersuite_t * ciphersuite_info )
933 {
934 mbedtls_ssl_key_cert *cur, *list, *fallback = NULL;
935 mbedtls_pk_type_t pk_alg =
936 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
937 uint32_t flags;
938
939 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
940 if( ssl->handshake->sni_key_cert != NULL )
941 list = ssl->handshake->sni_key_cert;
942 else
943 #endif
944 list = ssl->conf->key_cert;
945
946 if( pk_alg == MBEDTLS_PK_NONE )
947 return( 0 );
948
949 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) );
950
951 if( list == NULL )
952 {
953 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server has no certificate" ) );
954 return( -1 );
955 }
956
957 for( cur = list; cur != NULL; cur = cur->next )
958 {
959 flags = 0;
960 MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
961 cur->cert );
962
963 if( ! mbedtls_pk_can_do( &cur->cert->pk, pk_alg ) )
964 {
965 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) );
966 continue;
967 }
968
969 /*
970 * This avoids sending the client a cert it'll reject based on
971 * keyUsage or other extensions.
972 *
973 * It also allows the user to provision different certificates for
974 * different uses based on keyUsage, eg if they want to avoid signing
975 * and decrypting with the same RSA key.
976 */
977 if( mbedtls_ssl_check_cert_usage( cur->cert, ciphersuite_info,
978 MBEDTLS_SSL_IS_SERVER, &flags ) != 0 )
979 {
980 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
981 "(extended) key usage extension" ) );
982 continue;
983 }
984
985 #if defined(MBEDTLS_ECDSA_C)
986 if( pk_alg == MBEDTLS_PK_ECDSA &&
987 ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 0 )
988 {
989 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) );
990 continue;
991 }
992 #endif
993
994 /*
995 * Try to select a SHA-1 certificate for pre-1.2 clients, but still
996 * present them a SHA-higher cert rather than failing if it's the only
997 * one we got that satisfies the other conditions.
998 */
999 if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 &&
1000 cur->cert->sig_md != MBEDTLS_MD_SHA1 )
1001 {
1002 if( fallback == NULL )
1003 fallback = cur;
1004 {
1005 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate not preferred: "
1006 "sha-2 with pre-TLS 1.2 client" ) );
1007 continue;
1008 }
1009 }
1010
1011 /* If we get there, we got a winner */
1012 break;
1013 }
1014
1015 if( cur == NULL )
1016 cur = fallback;
1017
1018 /* Do not update ssl->handshake->key_cert unless there is a match */
1019 if( cur != NULL )
1020 {
1021 ssl->handshake->key_cert = cur;
1022 MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
1023 ssl->handshake->key_cert->cert );
1024 return( 0 );
1025 }
1026
1027 return( -1 );
1028 }
1029 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1030
1031 /*
1032 * Check if a given ciphersuite is suitable for use with our config/keys/etc
1033 * Sets ciphersuite_info only if the suite matches.
1034 */
ssl_ciphersuite_match(mbedtls_ssl_context * ssl,int suite_id,const mbedtls_ssl_ciphersuite_t ** ciphersuite_info)1035 static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id,
1036 const mbedtls_ssl_ciphersuite_t **ciphersuite_info )
1037 {
1038 const mbedtls_ssl_ciphersuite_t *suite_info;
1039
1040 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1041 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1042 mbedtls_pk_type_t sig_type;
1043 #endif
1044
1045 suite_info = mbedtls_ssl_ciphersuite_from_id( suite_id );
1046 if( suite_info == NULL )
1047 {
1048 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
1049 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
1050 }
1051
1052 MBEDTLS_SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %#04x (%s)",
1053 (unsigned int) suite_id, suite_info->name ) );
1054
1055 if( suite_info->min_minor_ver > ssl->minor_ver ||
1056 suite_info->max_minor_ver < ssl->minor_ver )
1057 {
1058 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) );
1059 return( 0 );
1060 }
1061
1062 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1063 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
1064 ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
1065 return( 0 );
1066 #endif
1067
1068 #if defined(MBEDTLS_ARC4_C)
1069 if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED &&
1070 suite_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
1071 {
1072 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) );
1073 return( 0 );
1074 }
1075 #endif
1076
1077 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1078 if( suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
1079 ( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK ) == 0 )
1080 {
1081 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: ecjpake "
1082 "not configured or ext missing" ) );
1083 return( 0 );
1084 }
1085 #endif
1086
1087
1088 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
1089 if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) &&
1090 ( ssl->handshake->curves == NULL ||
1091 ssl->handshake->curves[0] == NULL ) )
1092 {
1093 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
1094 "no common elliptic curve" ) );
1095 return( 0 );
1096 }
1097 #endif
1098
1099 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
1100 /* If the ciphersuite requires a pre-shared key and we don't
1101 * have one, skip it now rather than failing later */
1102 if( mbedtls_ssl_ciphersuite_uses_psk( suite_info ) &&
1103 ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
1104 {
1105 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) );
1106 return( 0 );
1107 }
1108 #endif
1109
1110 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1111 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1112 /* If the ciphersuite requires signing, check whether
1113 * a suitable hash algorithm is present. */
1114 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
1115 {
1116 sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
1117 if( sig_type != MBEDTLS_PK_NONE &&
1118 mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == MBEDTLS_MD_NONE )
1119 {
1120 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
1121 "for signature algorithm %u", (unsigned) sig_type ) );
1122 return( 0 );
1123 }
1124 }
1125
1126 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1127 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1128
1129 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1130 /*
1131 * Final check: if ciphersuite requires us to have a
1132 * certificate/key of a particular type:
1133 * - select the appropriate certificate if we have one, or
1134 * - try the next ciphersuite if we don't
1135 * This must be done last since we modify the key_cert list.
1136 */
1137 if( ssl_pick_cert( ssl, suite_info ) != 0 )
1138 {
1139 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
1140 "no suitable certificate" ) );
1141 return( 0 );
1142 }
1143 #endif
1144
1145 *ciphersuite_info = suite_info;
1146 return( 0 );
1147 }
1148
1149 #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
ssl_parse_client_hello_v2(mbedtls_ssl_context * ssl)1150 static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
1151 {
1152 int ret, got_common_suite;
1153 unsigned int i, j;
1154 size_t n;
1155 unsigned int ciph_len, sess_len, chal_len;
1156 unsigned char *buf, *p;
1157 const int *ciphersuites;
1158 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
1159
1160 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
1161
1162 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1163 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
1164 {
1165 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
1166 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1167 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1168 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1169 }
1170 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1171
1172 buf = ssl->in_hdr;
1173
1174 MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, 5 );
1175
1176 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
1177 buf[2] ) );
1178 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
1179 ( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
1180 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
1181 buf[3], buf[4] ) );
1182
1183 /*
1184 * SSLv2 Client Hello
1185 *
1186 * Record layer:
1187 * 0 . 1 message length
1188 *
1189 * SSL layer:
1190 * 2 . 2 message type
1191 * 3 . 4 protocol version
1192 */
1193 if( buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO ||
1194 buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3 )
1195 {
1196 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1197 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1198 }
1199
1200 n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
1201
1202 if( n < 17 || n > 512 )
1203 {
1204 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1205 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1206 }
1207
1208 ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3;
1209 ssl->minor_ver = ( buf[4] <= ssl->conf->max_minor_ver )
1210 ? buf[4] : ssl->conf->max_minor_ver;
1211
1212 if( ssl->minor_ver < ssl->conf->min_minor_ver )
1213 {
1214 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
1215 " [%d:%d] < [%d:%d]",
1216 ssl->major_ver, ssl->minor_ver,
1217 ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
1218
1219 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1220 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1221 return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
1222 }
1223
1224 ssl->handshake->max_major_ver = buf[3];
1225 ssl->handshake->max_minor_ver = buf[4];
1226
1227 if( ( ret = mbedtls_ssl_fetch_input( ssl, 2 + n ) ) != 0 )
1228 {
1229 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1230 return( ret );
1231 }
1232
1233 ssl->handshake->update_checksum( ssl, buf + 2, n );
1234
1235 buf = ssl->in_msg;
1236 n = ssl->in_left - 5;
1237
1238 /*
1239 * 0 . 1 ciphersuitelist length
1240 * 2 . 3 session id length
1241 * 4 . 5 challenge length
1242 * 6 . .. ciphersuitelist
1243 * .. . .. session id
1244 * .. . .. challenge
1245 */
1246 MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, n );
1247
1248 ciph_len = ( buf[0] << 8 ) | buf[1];
1249 sess_len = ( buf[2] << 8 ) | buf[3];
1250 chal_len = ( buf[4] << 8 ) | buf[5];
1251
1252 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciph_len: %u, sess_len: %u, chal_len: %u",
1253 ciph_len, sess_len, chal_len ) );
1254
1255 /*
1256 * Make sure each parameter length is valid
1257 */
1258 if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
1259 {
1260 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1261 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1262 }
1263
1264 if( sess_len > 32 )
1265 {
1266 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1267 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1268 }
1269
1270 if( chal_len < 8 || chal_len > 32 )
1271 {
1272 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1273 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1274 }
1275
1276 if( n != 6 + ciph_len + sess_len + chal_len )
1277 {
1278 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1279 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1280 }
1281
1282 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
1283 buf + 6, ciph_len );
1284 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id",
1285 buf + 6 + ciph_len, sess_len );
1286 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, challenge",
1287 buf + 6 + ciph_len + sess_len, chal_len );
1288
1289 p = buf + 6 + ciph_len;
1290 ssl->session_negotiate->id_len = sess_len;
1291 memset( ssl->session_negotiate->id, 0,
1292 sizeof( ssl->session_negotiate->id ) );
1293 memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len );
1294
1295 p += sess_len;
1296 memset( ssl->handshake->randbytes, 0, 64 );
1297 memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
1298
1299 /*
1300 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
1301 */
1302 for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
1303 {
1304 if( p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
1305 {
1306 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
1307 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1308 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1309 {
1310 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
1311 "during renegotiation" ) );
1312
1313 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1314 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1315 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1316 }
1317 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1318 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
1319 break;
1320 }
1321 }
1322
1323 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
1324 for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
1325 {
1326 if( p[0] == 0 &&
1327 MBEDTLS_GET_UINT16_BE(p, 1) != MBEDTLS_SSL_FALLBACK_SCSV_VALUE )
1328 {
1329 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
1330
1331 if( ssl->minor_ver < ssl->conf->max_minor_ver )
1332 {
1333 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
1334
1335 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1336 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
1337
1338 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
1339 }
1340
1341 break;
1342 }
1343 }
1344 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
1345
1346 got_common_suite = 0;
1347 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
1348 ciphersuite_info = NULL;
1349 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
1350 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
1351 for( i = 0; ciphersuites[i] != 0; i++ )
1352 #else
1353 for( i = 0; ciphersuites[i] != 0; i++ )
1354 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
1355 #endif
1356 {
1357 if( p[0] != 0 ||
1358 MBEDTLS_GET_UINT16_BE(p, 1) != ciphersuites[i] )
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( MBEDTLS_GET_UINT16_BE( p, 0 ) == MBEDTLS_SSL_FALLBACK_SCSV_VALUE )
2090 {
2091 MBEDTLS_SSL_DEBUG_MSG( 2, ( "received FALLBACK_SCSV" ) );
2092
2093 if( ssl->minor_ver < ssl->conf->max_minor_ver )
2094 {
2095 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
2096
2097 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2098 MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
2099
2100 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2101 }
2102
2103 break;
2104 }
2105 }
2106 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
2107
2108 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2109 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
2110
2111 /*
2112 * Try to fall back to default hash SHA1 if the client
2113 * hasn't provided any preferred signature-hash combinations.
2114 */
2115 if( sig_hash_alg_ext_present == 0 )
2116 {
2117 mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1;
2118
2119 if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 )
2120 md_default = MBEDTLS_MD_NONE;
2121
2122 mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default );
2123 }
2124
2125 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
2126 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
2127
2128 /*
2129 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
2130 */
2131 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
2132 {
2133 if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
2134 {
2135 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
2136 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2137 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
2138 {
2139 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
2140 "during renegotiation" ) );
2141 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2142 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2143 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2144 }
2145 #endif
2146 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
2147 break;
2148 }
2149 }
2150
2151 /*
2152 * Renegotiation security checks
2153 */
2154 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
2155 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
2156 {
2157 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
2158 handshake_failure = 1;
2159 }
2160 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2161 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2162 ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
2163 renegotiation_info_seen == 0 )
2164 {
2165 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
2166 handshake_failure = 1;
2167 }
2168 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2169 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
2170 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION )
2171 {
2172 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
2173 handshake_failure = 1;
2174 }
2175 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
2176 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
2177 renegotiation_info_seen == 1 )
2178 {
2179 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
2180 handshake_failure = 1;
2181 }
2182 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2183
2184 if( handshake_failure == 1 )
2185 {
2186 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2187 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2188 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
2189 }
2190
2191 /*
2192 * Search for a matching ciphersuite
2193 * (At the end because we need information from the EC-based extensions
2194 * and certificate from the SNI callback triggered by the SNI extension.)
2195 */
2196 got_common_suite = 0;
2197 ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
2198 ciphersuite_info = NULL;
2199 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
2200 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
2201 for( i = 0; ciphersuites[i] != 0; i++ )
2202 #else
2203 for( i = 0; ciphersuites[i] != 0; i++ )
2204 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
2205 #endif
2206 {
2207 if( MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i] )
2208 continue;
2209
2210 got_common_suite = 1;
2211
2212 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
2213 &ciphersuite_info ) ) != 0 )
2214 return( ret );
2215
2216 if( ciphersuite_info != NULL )
2217 goto have_ciphersuite;
2218 }
2219
2220 if( got_common_suite )
2221 {
2222 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
2223 "but none of them usable" ) );
2224 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2225 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2226 return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
2227 }
2228 else
2229 {
2230 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
2231 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
2232 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
2233 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
2234 }
2235
2236 have_ciphersuite:
2237 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
2238
2239 ssl->session_negotiate->ciphersuite = ciphersuites[i];
2240 ssl->handshake->ciphersuite_info = ciphersuite_info;
2241
2242 ssl->state++;
2243
2244 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2245 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
2246 mbedtls_ssl_recv_flight_completed( ssl );
2247 #endif
2248
2249 /* Debugging-only output for testsuite */
2250 #if defined(MBEDTLS_DEBUG_C) && \
2251 defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
2252 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
2253 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
2254 {
2255 mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info );
2256 if( sig_alg != MBEDTLS_PK_NONE )
2257 {
2258 mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
2259 sig_alg );
2260 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
2261 mbedtls_ssl_hash_from_md_alg( md_alg ) ) );
2262 }
2263 else
2264 {
2265 MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm "
2266 "%u - should not happen", (unsigned) sig_alg ) );
2267 }
2268 }
2269 #endif
2270
2271 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
2272
2273 return( 0 );
2274 }
2275
2276 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_write_truncated_hmac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2277 static void ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl,
2278 unsigned char *buf,
2279 size_t *olen )
2280 {
2281 unsigned char *p = buf;
2282
2283 if( ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED )
2284 {
2285 *olen = 0;
2286 return;
2287 }
2288
2289 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) );
2290
2291 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_TRUNCATED_HMAC, p, 0 );
2292 p += 2;
2293
2294 *p++ = 0x00;
2295 *p++ = 0x00;
2296
2297 *olen = 4;
2298 }
2299 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2300
2301 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_write_cid_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2302 static void ssl_write_cid_ext( mbedtls_ssl_context *ssl,
2303 unsigned char *buf,
2304 size_t *olen )
2305 {
2306 unsigned char *p = buf;
2307 size_t ext_len;
2308 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2309
2310 *olen = 0;
2311
2312 /* Skip writing the extension if we don't want to use it or if
2313 * the client hasn't offered it. */
2314 if( ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED )
2315 return;
2316
2317 /* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX
2318 * which is at most 255, so the increment cannot overflow. */
2319 if( end < p || (size_t)( end - p ) < (unsigned)( ssl->own_cid_len + 5 ) )
2320 {
2321 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2322 return;
2323 }
2324
2325 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding CID extension" ) );
2326
2327 /*
2328 * Quoting draft-ietf-tls-dtls-connection-id-05
2329 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
2330 *
2331 * struct {
2332 * opaque cid<0..2^8-1>;
2333 * } ConnectionId;
2334 */
2335 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_CID, p, 0 );
2336 p += 2;
2337 ext_len = (size_t) ssl->own_cid_len + 1;
2338 MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
2339 p += 2;
2340
2341 *p++ = (uint8_t) ssl->own_cid_len;
2342 memcpy( p, ssl->own_cid, ssl->own_cid_len );
2343
2344 *olen = ssl->own_cid_len + 5;
2345 }
2346 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
2347
2348 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2349 static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
2350 unsigned char *buf,
2351 size_t *olen )
2352 {
2353 unsigned char *p = buf;
2354 const mbedtls_ssl_ciphersuite_t *suite = NULL;
2355 const mbedtls_cipher_info_t *cipher = NULL;
2356
2357 if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ||
2358 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2359 {
2360 *olen = 0;
2361 return;
2362 }
2363
2364 /*
2365 * RFC 7366: "If a server receives an encrypt-then-MAC request extension
2366 * from a client and then selects a stream or Authenticated Encryption
2367 * with Associated Data (AEAD) ciphersuite, it MUST NOT send an
2368 * encrypt-then-MAC response extension back to the client."
2369 */
2370 if( ( suite = mbedtls_ssl_ciphersuite_from_id(
2371 ssl->session_negotiate->ciphersuite ) ) == NULL ||
2372 ( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL ||
2373 cipher->mode != MBEDTLS_MODE_CBC )
2374 {
2375 *olen = 0;
2376 return;
2377 }
2378
2379 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
2380
2381 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC, p, 0 );
2382 p += 2;
2383
2384 *p++ = 0x00;
2385 *p++ = 0x00;
2386
2387 *olen = 4;
2388 }
2389 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2390
2391 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2392 static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
2393 unsigned char *buf,
2394 size_t *olen )
2395 {
2396 unsigned char *p = buf;
2397
2398 if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED ||
2399 ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
2400 {
2401 *olen = 0;
2402 return;
2403 }
2404
2405 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
2406 "extension" ) );
2407
2408 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET, p, 0 );
2409 p += 2;
2410
2411 *p++ = 0x00;
2412 *p++ = 0x00;
2413
2414 *olen = 4;
2415 }
2416 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2417
2418 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2419 static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
2420 unsigned char *buf,
2421 size_t *olen )
2422 {
2423 unsigned char *p = buf;
2424
2425 if( ssl->handshake->new_session_ticket == 0 )
2426 {
2427 *olen = 0;
2428 return;
2429 }
2430
2431 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
2432
2433 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SESSION_TICKET, p, 0 );
2434 p += 2;
2435
2436 *p++ = 0x00;
2437 *p++ = 0x00;
2438
2439 *olen = 4;
2440 }
2441 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2442
ssl_write_renegotiation_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2443 static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
2444 unsigned char *buf,
2445 size_t *olen )
2446 {
2447 unsigned char *p = buf;
2448
2449 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION )
2450 {
2451 *olen = 0;
2452 return;
2453 }
2454
2455 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) );
2456
2457 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO, p, 0 );
2458 p += 2;
2459
2460 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2461 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2462 {
2463 *p++ = 0x00;
2464 *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF;
2465 *p++ = ssl->verify_data_len * 2 & 0xFF;
2466
2467 memcpy( p, ssl->peer_verify_data, ssl->verify_data_len );
2468 p += ssl->verify_data_len;
2469 memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
2470 p += ssl->verify_data_len;
2471 }
2472 else
2473 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2474 {
2475 *p++ = 0x00;
2476 *p++ = 0x01;
2477 *p++ = 0x00;
2478 }
2479
2480 *olen = p - buf;
2481 }
2482
2483 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2484 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
2485 unsigned char *buf,
2486 size_t *olen )
2487 {
2488 unsigned char *p = buf;
2489
2490 if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE )
2491 {
2492 *olen = 0;
2493 return;
2494 }
2495
2496 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
2497
2498 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH, p, 0 );
2499 p += 2;
2500
2501 *p++ = 0x00;
2502 *p++ = 1;
2503
2504 *p++ = ssl->session_negotiate->mfl_code;
2505
2506 *olen = 5;
2507 }
2508 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2509
2510 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2511 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_supported_point_formats_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2512 static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
2513 unsigned char *buf,
2514 size_t *olen )
2515 {
2516 unsigned char *p = buf;
2517 ((void) ssl);
2518
2519 if( ( ssl->handshake->cli_exts &
2520 MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
2521 {
2522 *olen = 0;
2523 return;
2524 }
2525
2526 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
2527
2528 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS, p, 0 );
2529 p += 2;
2530
2531 *p++ = 0x00;
2532 *p++ = 2;
2533
2534 *p++ = 1;
2535 *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
2536
2537 *olen = 6;
2538 }
2539 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2540
2541 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2542 static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
2543 unsigned char *buf,
2544 size_t *olen )
2545 {
2546 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2547 unsigned char *p = buf;
2548 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2549 size_t kkpp_len;
2550
2551 *olen = 0;
2552
2553 /* Skip costly computation if not needed */
2554 if( ssl->handshake->ciphersuite_info->key_exchange !=
2555 MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2556 return;
2557
2558 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, ecjpake kkpp extension" ) );
2559
2560 if( end - p < 4 )
2561 {
2562 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2563 return;
2564 }
2565
2566 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ECJPAKE_KKPP, p, 0 );
2567 p += 2;
2568
2569 ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
2570 p + 2, end - p - 2, &kkpp_len,
2571 ssl->conf->f_rng, ssl->conf->p_rng );
2572 if( ret != 0 )
2573 {
2574 MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
2575 return;
2576 }
2577
2578 MBEDTLS_PUT_UINT16_BE( kkpp_len, p, 0 );
2579 p += 2;
2580
2581 *olen = kkpp_len + 4;
2582 }
2583 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2584
2585 #if defined(MBEDTLS_SSL_ALPN )
ssl_write_alpn_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2586 static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
2587 unsigned char *buf, size_t *olen )
2588 {
2589 if( ssl->alpn_chosen == NULL )
2590 {
2591 *olen = 0;
2592 return;
2593 }
2594
2595 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
2596
2597 /*
2598 * 0 . 1 ext identifier
2599 * 2 . 3 ext length
2600 * 4 . 5 protocol list length
2601 * 6 . 6 protocol name length
2602 * 7 . 7+n protocol name
2603 */
2604 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ALPN, buf, 0);
2605
2606 *olen = 7 + strlen( ssl->alpn_chosen );
2607
2608 MBEDTLS_PUT_UINT16_BE( *olen - 4, buf, 2 );
2609
2610 MBEDTLS_PUT_UINT16_BE( *olen - 6, buf, 4 );
2611
2612 buf[6] = MBEDTLS_BYTE_0( *olen - 7 );
2613
2614 memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
2615 }
2616 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
2617
2618 #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)2619 static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
2620 unsigned char *buf,
2621 size_t *olen )
2622 {
2623 size_t mki_len = 0, ext_len = 0;
2624 uint16_t profile_value = 0;
2625 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2626
2627 *olen = 0;
2628
2629 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
2630 ( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET ) )
2631 {
2632 return;
2633 }
2634
2635 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding use_srtp extension" ) );
2636
2637 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED )
2638 {
2639 mki_len = ssl->dtls_srtp_info.mki_len;
2640 }
2641
2642 /* The extension total size is 9 bytes :
2643 * - 2 bytes for the extension tag
2644 * - 2 bytes for the total size
2645 * - 2 bytes for the protection profile length
2646 * - 2 bytes for the protection profile
2647 * - 1 byte for the mki length
2648 * + the actual mki length
2649 * Check we have enough room in the output buffer */
2650 if( (size_t)( end - buf ) < mki_len + 9 )
2651 {
2652 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2653 return;
2654 }
2655
2656 /* extension */
2657 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_USE_SRTP, buf, 0 );
2658 /*
2659 * total length 5 and mki value: only one profile(2 bytes)
2660 * and length(2 bytes) and srtp_mki )
2661 */
2662 ext_len = 5 + mki_len;
2663 MBEDTLS_PUT_UINT16_BE( ext_len, buf, 2 );
2664
2665 /* protection profile length: 2 */
2666 buf[4] = 0x00;
2667 buf[5] = 0x02;
2668 profile_value = mbedtls_ssl_check_srtp_profile_value(
2669 ssl->dtls_srtp_info.chosen_dtls_srtp_profile );
2670 if( profile_value != MBEDTLS_TLS_SRTP_UNSET )
2671 {
2672 MBEDTLS_PUT_UINT16_BE( profile_value, buf, 6 );
2673 }
2674 else
2675 {
2676 MBEDTLS_SSL_DEBUG_MSG( 1, ( "use_srtp extension invalid profile" ) );
2677 return;
2678 }
2679
2680 buf[8] = mki_len & 0xFF;
2681 memcpy( &buf[9], ssl->dtls_srtp_info.mki_value, mki_len );
2682
2683 *olen = 9 + mki_len;
2684 }
2685 #endif /* MBEDTLS_SSL_DTLS_SRTP */
2686
2687 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
ssl_write_hello_verify_request(mbedtls_ssl_context * ssl)2688 static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
2689 {
2690 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2691 unsigned char *p = ssl->out_msg + 4;
2692 unsigned char *cookie_len_byte;
2693
2694 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) );
2695
2696 /*
2697 * struct {
2698 * ProtocolVersion server_version;
2699 * opaque cookie<0..2^8-1>;
2700 * } HelloVerifyRequest;
2701 */
2702
2703 /* The RFC is not clear on this point, but sending the actual negotiated
2704 * version looks like the most interoperable thing to do. */
2705 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2706 ssl->conf->transport, p );
2707 MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 );
2708 p += 2;
2709
2710 /* If we get here, f_cookie_check is not null */
2711 if( ssl->conf->f_cookie_write == NULL )
2712 {
2713 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) );
2714 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2715 }
2716
2717 /* Skip length byte until we know the length */
2718 cookie_len_byte = p++;
2719
2720 if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
2721 &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
2722 ssl->cli_id, ssl->cli_id_len ) ) != 0 )
2723 {
2724 MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
2725 return( ret );
2726 }
2727
2728 *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) );
2729
2730 MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte );
2731
2732 ssl->out_msglen = p - ssl->out_msg;
2733 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2734 ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
2735
2736 ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
2737
2738 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
2739 {
2740 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
2741 return( ret );
2742 }
2743
2744 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2745 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2746 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
2747 {
2748 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
2749 return( ret );
2750 }
2751 #endif /* MBEDTLS_SSL_PROTO_DTLS */
2752
2753 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
2754
2755 return( 0 );
2756 }
2757 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2758
ssl_handle_id_based_session_resumption(mbedtls_ssl_context * ssl)2759 static void ssl_handle_id_based_session_resumption( mbedtls_ssl_context *ssl )
2760 {
2761 int ret;
2762 mbedtls_ssl_session session_tmp;
2763 mbedtls_ssl_session * const session = ssl->session_negotiate;
2764
2765 /* Resume is 0 by default, see ssl_handshake_init().
2766 * It may be already set to 1 by ssl_parse_session_ticket_ext(). */
2767 if( ssl->handshake->resume == 1 )
2768 return;
2769 if( session->id_len == 0 )
2770 return;
2771 if( ssl->conf->f_get_cache == NULL )
2772 return;
2773 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2774 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2775 return;
2776 #endif
2777
2778 mbedtls_ssl_session_init( &session_tmp );
2779
2780 session_tmp.id_len = session->id_len;
2781 memcpy( session_tmp.id, session->id, session->id_len );
2782
2783 ret = ssl->conf->f_get_cache( ssl->conf->p_cache,
2784 &session_tmp );
2785 if( ret != 0 )
2786 goto exit;
2787
2788 if( session->ciphersuite != session_tmp.ciphersuite ||
2789 session->compression != session_tmp.compression )
2790 {
2791 /* Mismatch between cached and negotiated session */
2792 goto exit;
2793 }
2794
2795 /* Move semantics */
2796 mbedtls_ssl_session_free( session );
2797 *session = session_tmp;
2798 memset( &session_tmp, 0, sizeof( session_tmp ) );
2799
2800 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
2801 ssl->handshake->resume = 1;
2802
2803 exit:
2804
2805 mbedtls_ssl_session_free( &session_tmp );
2806 }
2807
ssl_write_server_hello(mbedtls_ssl_context * ssl)2808 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
2809 {
2810 #if defined(MBEDTLS_HAVE_TIME)
2811 mbedtls_time_t t;
2812 #endif
2813 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2814 size_t olen, ext_len = 0, n;
2815 unsigned char *buf, *p;
2816
2817 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
2818
2819 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
2820 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2821 ssl->handshake->verify_cookie_len != 0 )
2822 {
2823 MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) );
2824 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2825
2826 return( ssl_write_hello_verify_request( ssl ) );
2827 }
2828 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2829
2830 if( ssl->conf->f_rng == NULL )
2831 {
2832 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
2833 return( MBEDTLS_ERR_SSL_NO_RNG );
2834 }
2835
2836 /*
2837 * 0 . 0 handshake type
2838 * 1 . 3 handshake length
2839 * 4 . 5 protocol version
2840 * 6 . 9 UNIX time()
2841 * 10 . 37 random bytes
2842 */
2843 buf = ssl->out_msg;
2844 p = buf + 4;
2845
2846 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2847 ssl->conf->transport, p );
2848 p += 2;
2849
2850 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
2851 buf[4], buf[5] ) );
2852
2853 #if defined(MBEDTLS_HAVE_TIME)
2854 t = mbedtls_time( NULL );
2855 MBEDTLS_PUT_UINT32_BE( t, p, 0 );
2856 p += 4;
2857
2858 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
2859 (long long) t ) );
2860 #else
2861 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 )
2862 return( ret );
2863
2864 p += 4;
2865 #endif /* MBEDTLS_HAVE_TIME */
2866
2867 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 )
2868 return( ret );
2869
2870 p += 28;
2871
2872 memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
2873
2874 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
2875
2876 ssl_handle_id_based_session_resumption( ssl );
2877
2878 if( ssl->handshake->resume == 0 )
2879 {
2880 /*
2881 * New session, create a new session id,
2882 * unless we're about to issue a session ticket
2883 */
2884 ssl->state++;
2885
2886 #if defined(MBEDTLS_HAVE_TIME)
2887 ssl->session_negotiate->start = mbedtls_time( NULL );
2888 #endif
2889
2890 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2891 if( ssl->handshake->new_session_ticket != 0 )
2892 {
2893 ssl->session_negotiate->id_len = n = 0;
2894 memset( ssl->session_negotiate->id, 0, 32 );
2895 }
2896 else
2897 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2898 {
2899 ssl->session_negotiate->id_len = n = 32;
2900 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id,
2901 n ) ) != 0 )
2902 return( ret );
2903 }
2904 }
2905 else
2906 {
2907 /*
2908 * Resuming a session
2909 */
2910 n = ssl->session_negotiate->id_len;
2911 ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
2912
2913 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
2914 {
2915 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
2916 return( ret );
2917 }
2918 }
2919
2920 /*
2921 * 38 . 38 session id length
2922 * 39 . 38+n session id
2923 * 39+n . 40+n chosen ciphersuite
2924 * 41+n . 41+n chosen compression alg.
2925 * 42+n . 43+n extensions length
2926 * 44+n . 43+n+m extensions
2927 */
2928 *p++ = (unsigned char) ssl->session_negotiate->id_len;
2929 memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
2930 p += ssl->session_negotiate->id_len;
2931
2932 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n ) );
2933 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
2934 MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
2935 ssl->handshake->resume ? "a" : "no" ) );
2936
2937 MBEDTLS_PUT_UINT16_BE( ssl->session_negotiate->ciphersuite, p, 0 );
2938 p += 2;
2939 *p++ = MBEDTLS_BYTE_0( ssl->session_negotiate->compression );
2940
2941 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s",
2942 mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
2943 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
2944 (unsigned int) ssl->session_negotiate->compression ) );
2945
2946 /* Do not write the extensions if the protocol is SSLv3 */
2947 #if defined(MBEDTLS_SSL_PROTO_SSL3)
2948 if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
2949 {
2950 #endif
2951
2952 /*
2953 * First write extensions, then the total length
2954 */
2955 ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
2956 ext_len += olen;
2957
2958 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2959 ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
2960 ext_len += olen;
2961 #endif
2962
2963 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2964 ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
2965 ext_len += olen;
2966 #endif
2967
2968 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2969 ssl_write_cid_ext( ssl, p + 2 + ext_len, &olen );
2970 ext_len += olen;
2971 #endif
2972
2973 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2974 ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
2975 ext_len += olen;
2976 #endif
2977
2978 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2979 ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
2980 ext_len += olen;
2981 #endif
2982
2983 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2984 ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
2985 ext_len += olen;
2986 #endif
2987
2988 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2989 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2990 if ( mbedtls_ssl_ciphersuite_uses_ec(
2991 mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
2992 {
2993 ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
2994 ext_len += olen;
2995 }
2996 #endif
2997
2998 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2999 ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
3000 ext_len += olen;
3001 #endif
3002
3003 #if defined(MBEDTLS_SSL_ALPN)
3004 ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
3005 ext_len += olen;
3006 #endif
3007
3008 #if defined(MBEDTLS_SSL_DTLS_SRTP)
3009 ssl_write_use_srtp_ext( ssl, p + 2 + ext_len, &olen );
3010 ext_len += olen;
3011 #endif
3012
3013 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %" MBEDTLS_PRINTF_SIZET,
3014 ext_len ) );
3015
3016 if( ext_len > 0 )
3017 {
3018 MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
3019 p += 2 + ext_len;
3020 }
3021
3022 #if defined(MBEDTLS_SSL_PROTO_SSL3)
3023 }
3024 #endif
3025
3026 ssl->out_msglen = p - buf;
3027 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3028 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
3029
3030 ret = mbedtls_ssl_write_handshake_msg( ssl );
3031
3032 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
3033
3034 return( ret );
3035 }
3036
3037 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_write_certificate_request(mbedtls_ssl_context * ssl)3038 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
3039 {
3040 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3041 ssl->handshake->ciphersuite_info;
3042
3043 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
3044
3045 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
3046 {
3047 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
3048 ssl->state++;
3049 return( 0 );
3050 }
3051
3052 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3053 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3054 }
3055 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_write_certificate_request(mbedtls_ssl_context * ssl)3056 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
3057 {
3058 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3059 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3060 ssl->handshake->ciphersuite_info;
3061 uint16_t dn_size, total_dn_size; /* excluding length bytes */
3062 size_t ct_len, sa_len; /* including length bytes */
3063 unsigned char *buf, *p;
3064 const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
3065 const mbedtls_x509_crt *crt;
3066 int authmode;
3067
3068 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
3069
3070 ssl->state++;
3071
3072 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
3073 if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
3074 authmode = ssl->handshake->sni_authmode;
3075 else
3076 #endif
3077 authmode = ssl->conf->authmode;
3078
3079 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ||
3080 authmode == MBEDTLS_SSL_VERIFY_NONE )
3081 {
3082 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
3083 return( 0 );
3084 }
3085
3086 /*
3087 * 0 . 0 handshake type
3088 * 1 . 3 handshake length
3089 * 4 . 4 cert type count
3090 * 5 .. m-1 cert types
3091 * m .. m+1 sig alg length (TLS 1.2 only)
3092 * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
3093 * n .. n+1 length of all DNs
3094 * n+2 .. n+3 length of DN 1
3095 * n+4 .. ... Distinguished Name #1
3096 * ... .. ... length of DN 2, etc.
3097 */
3098 buf = ssl->out_msg;
3099 p = buf + 4;
3100
3101 /*
3102 * Supported certificate types
3103 *
3104 * ClientCertificateType certificate_types<1..2^8-1>;
3105 * enum { (255) } ClientCertificateType;
3106 */
3107 ct_len = 0;
3108
3109 #if defined(MBEDTLS_RSA_C)
3110 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
3111 #endif
3112 #if defined(MBEDTLS_ECDSA_C)
3113 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
3114 #endif
3115
3116 p[0] = (unsigned char) ct_len++;
3117 p += ct_len;
3118
3119 sa_len = 0;
3120 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3121 /*
3122 * Add signature_algorithms for verify (TLS 1.2)
3123 *
3124 * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
3125 *
3126 * struct {
3127 * HashAlgorithm hash;
3128 * SignatureAlgorithm signature;
3129 * } SignatureAndHashAlgorithm;
3130 *
3131 * enum { (255) } HashAlgorithm;
3132 * enum { (255) } SignatureAlgorithm;
3133 */
3134 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3135 {
3136 const int *cur;
3137
3138 /*
3139 * Supported signature algorithms
3140 */
3141 for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ )
3142 {
3143 unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur );
3144
3145 if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) )
3146 continue;
3147
3148 #if defined(MBEDTLS_RSA_C)
3149 p[2 + sa_len++] = hash;
3150 p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA;
3151 #endif
3152 #if defined(MBEDTLS_ECDSA_C)
3153 p[2 + sa_len++] = hash;
3154 p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA;
3155 #endif
3156 }
3157
3158 MBEDTLS_PUT_UINT16_BE( sa_len, p, 0 );
3159 sa_len += 2;
3160 p += sa_len;
3161 }
3162 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3163
3164 /*
3165 * DistinguishedName certificate_authorities<0..2^16-1>;
3166 * opaque DistinguishedName<1..2^16-1>;
3167 */
3168 p += 2;
3169
3170 total_dn_size = 0;
3171
3172 if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED )
3173 {
3174 /* NOTE: If trusted certificates are provisioned
3175 * via a CA callback (configured through
3176 * `mbedtls_ssl_conf_ca_cb()`, then the
3177 * CertificateRequest is currently left empty. */
3178
3179 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
3180 if( ssl->handshake->sni_ca_chain != NULL )
3181 crt = ssl->handshake->sni_ca_chain;
3182 else
3183 #endif
3184 crt = ssl->conf->ca_chain;
3185
3186 while( crt != NULL && crt->version != 0 )
3187 {
3188 /* It follows from RFC 5280 A.1 that this length
3189 * can be represented in at most 11 bits. */
3190 dn_size = (uint16_t) crt->subject_raw.len;
3191
3192 if( end < p || (size_t)( end - p ) < 2 + (size_t) dn_size )
3193 {
3194 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) );
3195 break;
3196 }
3197
3198 MBEDTLS_PUT_UINT16_BE( dn_size, p, 0 );
3199 p += 2;
3200 memcpy( p, crt->subject_raw.p, dn_size );
3201 p += dn_size;
3202
3203 MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size );
3204
3205 total_dn_size += 2 + dn_size;
3206 crt = crt->next;
3207 }
3208 }
3209
3210 ssl->out_msglen = p - buf;
3211 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3212 ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
3213 MBEDTLS_PUT_UINT16_BE( total_dn_size, ssl->out_msg, 4 + ct_len + sa_len );
3214
3215 ret = mbedtls_ssl_write_handshake_msg( ssl );
3216
3217 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
3218
3219 return( ret );
3220 }
3221 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
3222
3223 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
3224 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
ssl_get_ecdh_params_from_cert(mbedtls_ssl_context * ssl)3225 static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
3226 {
3227 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3228
3229 if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) )
3230 {
3231 MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
3232 return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
3233 }
3234
3235 if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx,
3236 mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ),
3237 MBEDTLS_ECDH_OURS ) ) != 0 )
3238 {
3239 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret );
3240 return( ret );
3241 }
3242
3243 return( 0 );
3244 }
3245 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
3246 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
3247
3248 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3249 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
ssl_resume_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)3250 static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
3251 size_t *signature_len )
3252 {
3253 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3254 * signature length which will be added in ssl_write_server_key_exchange
3255 * after the call to ssl_prepare_server_key_exchange.
3256 * ssl_write_server_key_exchange also takes care of incrementing
3257 * ssl->out_msglen. */
3258 unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
3259 size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
3260 - sig_start );
3261 int ret = ssl->conf->f_async_resume( ssl,
3262 sig_start, signature_len, sig_max_len );
3263 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3264 {
3265 ssl->handshake->async_in_progress = 0;
3266 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3267 }
3268 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
3269 return( ret );
3270 }
3271 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3272 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3273
3274 /* Prepare the ServerKeyExchange message, up to and including
3275 * calculating the signature if any, but excluding formatting the
3276 * signature and sending the message. */
ssl_prepare_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)3277 static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
3278 size_t *signature_len )
3279 {
3280 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3281 ssl->handshake->ciphersuite_info;
3282
3283 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED)
3284 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3285 unsigned char *dig_signed = NULL;
3286 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3287 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */
3288
3289 (void) ciphersuite_info; /* unused in some configurations */
3290 #if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3291 (void) signature_len;
3292 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3293
3294 ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
3295
3296 /*
3297 *
3298 * Part 1: Provide key exchange parameters for chosen ciphersuite.
3299 *
3300 */
3301
3302 /*
3303 * - ECJPAKE key exchanges
3304 */
3305 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3306 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
3307 {
3308 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3309 size_t len = 0;
3310
3311 ret = mbedtls_ecjpake_write_round_two(
3312 &ssl->handshake->ecjpake_ctx,
3313 ssl->out_msg + ssl->out_msglen,
3314 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
3315 ssl->conf->f_rng, ssl->conf->p_rng );
3316 if( ret != 0 )
3317 {
3318 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret );
3319 return( ret );
3320 }
3321
3322 ssl->out_msglen += len;
3323 }
3324 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
3325
3326 /*
3327 * For (EC)DHE key exchanges with PSK, parameters are prefixed by support
3328 * identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
3329 * we use empty support identity hints here.
3330 **/
3331 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
3332 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
3333 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
3334 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
3335 {
3336 ssl->out_msg[ssl->out_msglen++] = 0x00;
3337 ssl->out_msg[ssl->out_msglen++] = 0x00;
3338 }
3339 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
3340 MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
3341
3342 /*
3343 * - DHE key exchanges
3344 */
3345 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED)
3346 if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
3347 {
3348 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3349 size_t len = 0;
3350
3351 if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
3352 {
3353 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) );
3354 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
3355 }
3356
3357 /*
3358 * Ephemeral DH parameters:
3359 *
3360 * struct {
3361 * opaque dh_p<1..2^16-1>;
3362 * opaque dh_g<1..2^16-1>;
3363 * opaque dh_Ys<1..2^16-1>;
3364 * } ServerDHParams;
3365 */
3366 if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx,
3367 &ssl->conf->dhm_P,
3368 &ssl->conf->dhm_G ) ) != 0 )
3369 {
3370 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret );
3371 return( ret );
3372 }
3373
3374 if( ( ret = mbedtls_dhm_make_params(
3375 &ssl->handshake->dhm_ctx,
3376 (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
3377 ssl->out_msg + ssl->out_msglen, &len,
3378 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3379 {
3380 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret );
3381 return( ret );
3382 }
3383
3384 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3385 dig_signed = ssl->out_msg + ssl->out_msglen;
3386 #endif
3387
3388 ssl->out_msglen += len;
3389
3390 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
3391 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
3392 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
3393 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
3394 }
3395 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */
3396
3397 /*
3398 * - ECDHE key exchanges
3399 */
3400 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED)
3401 if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) )
3402 {
3403 /*
3404 * Ephemeral ECDH parameters:
3405 *
3406 * struct {
3407 * ECParameters curve_params;
3408 * ECPoint public;
3409 * } ServerECDHParams;
3410 */
3411 const mbedtls_ecp_curve_info **curve = NULL;
3412 const mbedtls_ecp_group_id *gid;
3413 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3414 size_t len = 0;
3415
3416 /* Match our preference list against the offered curves */
3417 for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ )
3418 for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
3419 if( (*curve)->grp_id == *gid )
3420 goto curve_matching_done;
3421
3422 curve_matching_done:
3423 if( curve == NULL || *curve == NULL )
3424 {
3425 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
3426 return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
3427 }
3428
3429 MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
3430
3431 if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
3432 (*curve)->grp_id ) ) != 0 )
3433 {
3434 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
3435 return( ret );
3436 }
3437
3438 if( ( ret = mbedtls_ecdh_make_params(
3439 &ssl->handshake->ecdh_ctx, &len,
3440 ssl->out_msg + ssl->out_msglen,
3441 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
3442 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3443 {
3444 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
3445 return( ret );
3446 }
3447
3448 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3449 dig_signed = ssl->out_msg + ssl->out_msglen;
3450 #endif
3451
3452 ssl->out_msglen += len;
3453
3454 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3455 MBEDTLS_DEBUG_ECDH_Q );
3456 }
3457 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */
3458
3459 /*
3460 *
3461 * Part 2: For key exchanges involving the server signing the
3462 * exchange parameters, compute and add the signature here.
3463 *
3464 */
3465 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3466 if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
3467 {
3468 size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
3469 size_t hashlen = 0;
3470 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3471 unsigned char hash[PSA_HASH_MAX_SIZE];
3472 #else
3473 unsigned char hash[MBEDTLS_MD_MAX_SIZE];
3474 #endif
3475 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3476
3477 /*
3478 * 2.1: Choose hash algorithm:
3479 * A: For TLS 1.2, obey signature-hash-algorithm extension
3480 * to choose appropriate hash.
3481 * B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1
3482 * (RFC 4492, Sec. 5.4)
3483 * C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3)
3484 */
3485
3486 mbedtls_md_type_t md_alg;
3487
3488 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3489 mbedtls_pk_type_t sig_alg =
3490 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
3491 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3492 {
3493 /* A: For TLS 1.2, obey signature-hash-algorithm extension
3494 * (RFC 5246, Sec. 7.4.1.4.1). */
3495 if( sig_alg == MBEDTLS_PK_NONE ||
3496 ( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
3497 sig_alg ) ) == MBEDTLS_MD_NONE )
3498 {
3499 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3500 /* (... because we choose a cipher suite
3501 * only if there is a matching hash.) */
3502 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3503 }
3504 }
3505 else
3506 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3507 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3508 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3509 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
3510 {
3511 /* B: Default hash SHA1 */
3512 md_alg = MBEDTLS_MD_SHA1;
3513 }
3514 else
3515 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3516 MBEDTLS_SSL_PROTO_TLS1_1 */
3517 {
3518 /* C: MD5 + SHA1 */
3519 md_alg = MBEDTLS_MD_NONE;
3520 }
3521
3522 MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %u for signing", (unsigned) md_alg ) );
3523
3524 /*
3525 * 2.2: Compute the hash to be signed
3526 */
3527 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
3528 defined(MBEDTLS_SSL_PROTO_TLS1_1)
3529 if( md_alg == MBEDTLS_MD_NONE )
3530 {
3531 hashlen = 36;
3532 ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash,
3533 dig_signed,
3534 dig_signed_len );
3535 if( ret != 0 )
3536 return( ret );
3537 }
3538 else
3539 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
3540 MBEDTLS_SSL_PROTO_TLS1_1 */
3541 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3542 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3543 if( md_alg != MBEDTLS_MD_NONE )
3544 {
3545 ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
3546 dig_signed,
3547 dig_signed_len,
3548 md_alg );
3549 if( ret != 0 )
3550 return( ret );
3551 }
3552 else
3553 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
3554 MBEDTLS_SSL_PROTO_TLS1_2 */
3555 {
3556 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3557 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3558 }
3559
3560 MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
3561
3562 /*
3563 * 2.3: Compute and add the signature
3564 */
3565 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3566 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3567 {
3568 /*
3569 * For TLS 1.2, we need to specify signature and hash algorithm
3570 * explicitly through a prefix to the signature.
3571 *
3572 * struct {
3573 * HashAlgorithm hash;
3574 * SignatureAlgorithm signature;
3575 * } SignatureAndHashAlgorithm;
3576 *
3577 * struct {
3578 * SignatureAndHashAlgorithm algorithm;
3579 * opaque signature<0..2^16-1>;
3580 * } DigitallySigned;
3581 *
3582 */
3583
3584 ssl->out_msg[ssl->out_msglen++] =
3585 mbedtls_ssl_hash_from_md_alg( md_alg );
3586 ssl->out_msg[ssl->out_msglen++] =
3587 mbedtls_ssl_sig_from_pk_alg( sig_alg );
3588 }
3589 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3590
3591 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3592 if( ssl->conf->f_async_sign_start != NULL )
3593 {
3594 ret = ssl->conf->f_async_sign_start( ssl,
3595 mbedtls_ssl_own_cert( ssl ),
3596 md_alg, hash, hashlen );
3597 switch( ret )
3598 {
3599 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3600 /* act as if f_async_sign was null */
3601 break;
3602 case 0:
3603 ssl->handshake->async_in_progress = 1;
3604 return( ssl_resume_server_key_exchange( ssl, signature_len ) );
3605 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3606 ssl->handshake->async_in_progress = 1;
3607 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3608 default:
3609 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret );
3610 return( ret );
3611 }
3612 }
3613 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3614
3615 if( mbedtls_ssl_own_key( ssl ) == NULL )
3616 {
3617 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) );
3618 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3619 }
3620
3621 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3622 * signature length which will be added in ssl_write_server_key_exchange
3623 * after the call to ssl_prepare_server_key_exchange.
3624 * ssl_write_server_key_exchange also takes care of incrementing
3625 * ssl->out_msglen. */
3626 if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ),
3627 md_alg, hash, hashlen,
3628 ssl->out_msg + ssl->out_msglen + 2,
3629 signature_len,
3630 ssl->conf->f_rng,
3631 ssl->conf->p_rng ) ) != 0 )
3632 {
3633 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret );
3634 return( ret );
3635 }
3636 }
3637 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3638
3639 return( 0 );
3640 }
3641
3642 /* Prepare the ServerKeyExchange message and send it. For ciphersuites
3643 * that do not include a ServerKeyExchange message, do nothing. Either
3644 * way, if successful, move on to the next step in the SSL state
3645 * machine. */
ssl_write_server_key_exchange(mbedtls_ssl_context * ssl)3646 static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
3647 {
3648 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3649 size_t signature_len = 0;
3650 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3651 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3652 ssl->handshake->ciphersuite_info;
3653 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3654
3655 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
3656
3657 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3658 /* Extract static ECDH parameters and abort if ServerKeyExchange
3659 * is not needed. */
3660 if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) )
3661 {
3662 /* For suites involving ECDH, extract DH parameters
3663 * from certificate at this point. */
3664 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED)
3665 if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) )
3666 {
3667 ssl_get_ecdh_params_from_cert( ssl );
3668 }
3669 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */
3670
3671 /* Key exchanges not involving ephemeral keys don't use
3672 * ServerKeyExchange, so end here. */
3673 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
3674 ssl->state++;
3675 return( 0 );
3676 }
3677 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3678
3679 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3680 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3681 /* If we have already prepared the message and there is an ongoing
3682 * signature operation, resume signing. */
3683 if( ssl->handshake->async_in_progress != 0 )
3684 {
3685 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) );
3686 ret = ssl_resume_server_key_exchange( ssl, &signature_len );
3687 }
3688 else
3689 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3690 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3691 {
3692 /* ServerKeyExchange is needed. Prepare the message. */
3693 ret = ssl_prepare_server_key_exchange( ssl, &signature_len );
3694 }
3695
3696 if( ret != 0 )
3697 {
3698 /* If we're starting to write a new message, set ssl->out_msglen
3699 * to 0. But if we're resuming after an asynchronous message,
3700 * out_msglen is the amount of data written so far and mst be
3701 * preserved. */
3702 if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3703 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) );
3704 else
3705 ssl->out_msglen = 0;
3706 return( ret );
3707 }
3708
3709 /* If there is a signature, write its length.
3710 * ssl_prepare_server_key_exchange already wrote the signature
3711 * itself at its proper place in the output buffer. */
3712 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3713 if( signature_len != 0 )
3714 {
3715 ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_1( signature_len );
3716 ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_0( signature_len );
3717
3718 MBEDTLS_SSL_DEBUG_BUF( 3, "my signature",
3719 ssl->out_msg + ssl->out_msglen,
3720 signature_len );
3721
3722 /* Skip over the already-written signature */
3723 ssl->out_msglen += signature_len;
3724 }
3725 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3726
3727 /* Add header and send. */
3728 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3729 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
3730
3731 ssl->state++;
3732
3733 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3734 {
3735 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3736 return( ret );
3737 }
3738
3739 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
3740 return( 0 );
3741 }
3742
ssl_write_server_hello_done(mbedtls_ssl_context * ssl)3743 static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
3744 {
3745 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3746
3747 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
3748
3749 ssl->out_msglen = 4;
3750 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3751 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
3752
3753 ssl->state++;
3754
3755 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3756 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
3757 mbedtls_ssl_send_flight_completed( ssl );
3758 #endif
3759
3760 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3761 {
3762 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3763 return( ret );
3764 }
3765
3766 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3767 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
3768 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
3769 {
3770 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
3771 return( ret );
3772 }
3773 #endif /* MBEDTLS_SSL_PROTO_DTLS */
3774
3775 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
3776
3777 return( 0 );
3778 }
3779
3780 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
3781 defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
ssl_parse_client_dh_public(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3782 static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p,
3783 const unsigned char *end )
3784 {
3785 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3786 size_t n;
3787
3788 /*
3789 * Receive G^Y mod P, premaster = (G^Y)^X mod P
3790 */
3791 if( *p + 2 > end )
3792 {
3793 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3794 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3795 }
3796
3797 n = ( (*p)[0] << 8 ) | (*p)[1];
3798 *p += 2;
3799
3800 if( *p + n > end )
3801 {
3802 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3803 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3804 }
3805
3806 if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 )
3807 {
3808 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret );
3809 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
3810 }
3811
3812 *p += n;
3813
3814 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
3815
3816 return( ret );
3817 }
3818 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
3819 MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3820
3821 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3822 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3823
3824 #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)3825 static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl,
3826 unsigned char *peer_pms,
3827 size_t *peer_pmslen,
3828 size_t peer_pmssize )
3829 {
3830 int ret = ssl->conf->f_async_resume( ssl,
3831 peer_pms, peer_pmslen, peer_pmssize );
3832 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3833 {
3834 ssl->handshake->async_in_progress = 0;
3835 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3836 }
3837 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret );
3838 return( ret );
3839 }
3840 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3841
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)3842 static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl,
3843 const unsigned char *p,
3844 const unsigned char *end,
3845 unsigned char *peer_pms,
3846 size_t *peer_pmslen,
3847 size_t peer_pmssize )
3848 {
3849 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3850 mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl );
3851 mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk;
3852 size_t len = mbedtls_pk_get_len( public_key );
3853
3854 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3855 /* If we have already started decoding the message and there is an ongoing
3856 * decryption operation, resume signing. */
3857 if( ssl->handshake->async_in_progress != 0 )
3858 {
3859 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) );
3860 return( ssl_resume_decrypt_pms( ssl,
3861 peer_pms, peer_pmslen, peer_pmssize ) );
3862 }
3863 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3864
3865 /*
3866 * Prepare to decrypt the premaster using own private RSA key
3867 */
3868 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
3869 defined(MBEDTLS_SSL_PROTO_TLS1_2)
3870 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
3871 {
3872 if ( p + 2 > end )
3873 {
3874 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3875 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3876 }
3877 if( *p++ != MBEDTLS_BYTE_1( len ) ||
3878 *p++ != MBEDTLS_BYTE_0( len ) )
3879 {
3880 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3881 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3882 }
3883 }
3884 #endif
3885
3886 if( p + len != end )
3887 {
3888 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3889 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
3890 }
3891
3892 /*
3893 * Decrypt the premaster secret
3894 */
3895 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3896 if( ssl->conf->f_async_decrypt_start != NULL )
3897 {
3898 ret = ssl->conf->f_async_decrypt_start( ssl,
3899 mbedtls_ssl_own_cert( ssl ),
3900 p, len );
3901 switch( ret )
3902 {
3903 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3904 /* act as if f_async_decrypt_start was null */
3905 break;
3906 case 0:
3907 ssl->handshake->async_in_progress = 1;
3908 return( ssl_resume_decrypt_pms( ssl,
3909 peer_pms,
3910 peer_pmslen,
3911 peer_pmssize ) );
3912 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3913 ssl->handshake->async_in_progress = 1;
3914 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3915 default:
3916 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret );
3917 return( ret );
3918 }
3919 }
3920 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3921
3922 if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) )
3923 {
3924 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
3925 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3926 }
3927
3928 ret = mbedtls_pk_decrypt( private_key, p, len,
3929 peer_pms, peer_pmslen, peer_pmssize,
3930 ssl->conf->f_rng, ssl->conf->p_rng );
3931 return( ret );
3932 }
3933
ssl_parse_encrypted_pms(mbedtls_ssl_context * ssl,const unsigned char * p,const unsigned char * end,size_t pms_offset)3934 static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
3935 const unsigned char *p,
3936 const unsigned char *end,
3937 size_t pms_offset )
3938 {
3939 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3940 unsigned char *pms = ssl->handshake->premaster + pms_offset;
3941 unsigned char ver[2];
3942 unsigned char fake_pms[48], peer_pms[48];
3943 unsigned char mask;
3944 size_t i, peer_pmslen;
3945 unsigned int diff;
3946
3947 /* In case of a failure in decryption, the decryption may write less than
3948 * 2 bytes of output, but we always read the first two bytes. It doesn't
3949 * matter in the end because diff will be nonzero in that case due to
3950 * ret being nonzero, and we only care whether diff is 0.
3951 * But do initialize peer_pms and peer_pmslen for robustness anyway. This
3952 * also makes memory analyzers happy (don't access uninitialized memory,
3953 * even if it's an unsigned char). */
3954 peer_pms[0] = peer_pms[1] = ~0;
3955 peer_pmslen = 0;
3956
3957 ret = ssl_decrypt_encrypted_pms( ssl, p, end,
3958 peer_pms,
3959 &peer_pmslen,
3960 sizeof( peer_pms ) );
3961
3962 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3963 if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3964 return( ret );
3965 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3966
3967 mbedtls_ssl_write_version( ssl->handshake->max_major_ver,
3968 ssl->handshake->max_minor_ver,
3969 ssl->conf->transport, ver );
3970
3971 /* Avoid data-dependent branches while checking for invalid
3972 * padding, to protect against timing-based Bleichenbacher-type
3973 * attacks. */
3974 diff = (unsigned int) ret;
3975 diff |= peer_pmslen ^ 48;
3976 diff |= peer_pms[0] ^ ver[0];
3977 diff |= peer_pms[1] ^ ver[1];
3978
3979 /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
3980 mask = mbedtls_ct_uint_mask( diff );
3981
3982 /*
3983 * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
3984 * must not cause the connection to end immediately; instead, send a
3985 * bad_record_mac later in the handshake.
3986 * To protect against timing-based variants of the attack, we must
3987 * not have any branch that depends on whether the decryption was
3988 * successful. In particular, always generate the fake premaster secret,
3989 * regardless of whether it will ultimately influence the output or not.
3990 */
3991 ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) );
3992 if( ret != 0 )
3993 {
3994 /* It's ok to abort on an RNG failure, since this does not reveal
3995 * anything about the RSA decryption. */
3996 return( ret );
3997 }
3998
3999 #if defined(MBEDTLS_SSL_DEBUG_ALL)
4000 if( diff != 0 )
4001 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4002 #endif
4003
4004 if( sizeof( ssl->handshake->premaster ) < pms_offset ||
4005 sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
4006 {
4007 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4008 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4009 }
4010 ssl->handshake->pmslen = 48;
4011
4012 /* Set pms to either the true or the fake PMS, without
4013 * data-dependent branches. */
4014 for( i = 0; i < ssl->handshake->pmslen; i++ )
4015 pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
4016
4017 return( 0 );
4018 }
4019 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
4020 MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
4021
4022 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
ssl_parse_client_psk_identity(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)4023 static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p,
4024 const unsigned char *end )
4025 {
4026 int ret = 0;
4027 uint16_t n;
4028
4029 if( ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
4030 {
4031 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
4032 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
4033 }
4034
4035 /*
4036 * Receive client pre-shared key identity name
4037 */
4038 if( end - *p < 2 )
4039 {
4040 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4041 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4042 }
4043
4044 n = ( (*p)[0] << 8 ) | (*p)[1];
4045 *p += 2;
4046
4047 if( n == 0 || n > end - *p )
4048 {
4049 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4050 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4051 }
4052
4053 if( ssl->conf->f_psk != NULL )
4054 {
4055 if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 )
4056 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
4057 }
4058 else
4059 {
4060 /* Identity is not a big secret since clients send it in the clear,
4061 * but treat it carefully anyway, just in case */
4062 if( n != ssl->conf->psk_identity_len ||
4063 mbedtls_ct_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
4064 {
4065 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
4066 }
4067 }
4068
4069 if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
4070 {
4071 MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
4072 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
4073 MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
4074 return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
4075 }
4076
4077 *p += n;
4078
4079 return( 0 );
4080 }
4081 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
4082
ssl_parse_client_key_exchange(mbedtls_ssl_context * ssl)4083 static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
4084 {
4085 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4086 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
4087 unsigned char *p, *end;
4088
4089 ciphersuite_info = ssl->handshake->ciphersuite_info;
4090
4091 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
4092
4093 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
4094 ( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
4095 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
4096 if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
4097 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) &&
4098 ( ssl->handshake->async_in_progress != 0 ) )
4099 {
4100 /* We've already read a record and there is an asynchronous
4101 * operation in progress to decrypt it. So skip reading the
4102 * record. */
4103 MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) );
4104 }
4105 else
4106 #endif
4107 if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
4108 {
4109 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
4110 return( ret );
4111 }
4112
4113 p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
4114 end = ssl->in_msg + ssl->in_hslen;
4115
4116 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
4117 {
4118 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4119 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4120 }
4121
4122 if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
4123 {
4124 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
4125 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4126 }
4127
4128 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
4129 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
4130 {
4131 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
4132 {
4133 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
4134 return( ret );
4135 }
4136
4137 if( p != end )
4138 {
4139 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4140 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4141 }
4142
4143 if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
4144 ssl->handshake->premaster,
4145 MBEDTLS_PREMASTER_SIZE,
4146 &ssl->handshake->pmslen,
4147 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
4148 {
4149 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
4150 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
4151 }
4152
4153 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
4154 }
4155 else
4156 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
4157 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
4158 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
4159 defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
4160 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
4161 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
4162 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
4163 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
4164 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
4165 {
4166 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
4167 p, end - p) ) != 0 )
4168 {
4169 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
4170 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
4171 }
4172
4173 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4174 MBEDTLS_DEBUG_ECDH_QP );
4175
4176 if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
4177 &ssl->handshake->pmslen,
4178 ssl->handshake->premaster,
4179 MBEDTLS_MPI_MAX_SIZE,
4180 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
4181 {
4182 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
4183 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
4184 }
4185
4186 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4187 MBEDTLS_DEBUG_ECDH_Z );
4188 }
4189 else
4190 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
4191 MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
4192 MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
4193 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
4194 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
4195 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
4196 {
4197 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4198 {
4199 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4200 return( ret );
4201 }
4202
4203 if( p != end )
4204 {
4205 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4206 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4207 }
4208
4209 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4210 /* For opaque PSKs, we perform the PSK-to-MS derivation atomatically
4211 * and skip the intermediate PMS. */
4212 if( ssl_use_opaque_psk( ssl ) == 1 )
4213 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skip PMS generation for opaque PSK" ) );
4214 else
4215 #endif /* MBEDTLS_USE_PSA_CRYPTO */
4216 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4217 ciphersuite_info->key_exchange ) ) != 0 )
4218 {
4219 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4220 return( ret );
4221 }
4222 }
4223 else
4224 #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
4225 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
4226 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
4227 {
4228 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
4229 if ( ssl->handshake->async_in_progress != 0 )
4230 {
4231 /* There is an asynchronous operation in progress to
4232 * decrypt the encrypted premaster secret, so skip
4233 * directly to resuming this operation. */
4234 MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) );
4235 /* Update p to skip the PSK identity. ssl_parse_encrypted_pms
4236 * won't actually use it, but maintain p anyway for robustness. */
4237 p += ssl->conf->psk_identity_len + 2;
4238 }
4239 else
4240 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
4241 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4242 {
4243 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4244 return( ret );
4245 }
4246
4247 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4248 /* Opaque PSKs are currently only supported for PSK-only. */
4249 if( ssl_use_opaque_psk( ssl ) == 1 )
4250 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4251 #endif
4252
4253 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
4254 {
4255 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
4256 return( ret );
4257 }
4258
4259 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4260 ciphersuite_info->key_exchange ) ) != 0 )
4261 {
4262 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4263 return( ret );
4264 }
4265 }
4266 else
4267 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
4268 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
4269 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
4270 {
4271 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4272 {
4273 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4274 return( ret );
4275 }
4276 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
4277 {
4278 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
4279 return( ret );
4280 }
4281
4282 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4283 /* Opaque PSKs are currently only supported for PSK-only. */
4284 if( ssl_use_opaque_psk( ssl ) == 1 )
4285 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4286 #endif
4287
4288 if( p != end )
4289 {
4290 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
4291 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
4292 }
4293
4294 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4295 ciphersuite_info->key_exchange ) ) != 0 )
4296 {
4297 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4298 return( ret );
4299 }
4300 }
4301 else
4302 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
4303 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
4304 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
4305 {
4306 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
4307 {
4308 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
4309 return( ret );
4310 }
4311
4312 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
4313 p, end - p ) ) != 0 )
4314 {
4315 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
4316 return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
4317 }
4318
4319 #if defined(MBEDTLS_USE_PSA_CRYPTO)
4320 /* Opaque PSKs are currently only supported for PSK-only. */
4321 if( ssl_use_opaque_psk( ssl ) == 1 )
4322 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
4323 #endif
4324
4325 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
4326 MBEDTLS_DEBUG_ECDH_QP );
4327
4328 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
4329 ciphersuite_info->key_exchange ) ) != 0 )
4330 {
4331 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
4332 return( ret );
4333 }
4334 }
4335 else
4336 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
4337 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
4338 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
4339 {
4340 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 )
4341 {
4342 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
4343 return( ret );
4344 }
4345 }
4346 else
4347 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
4348 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
4349 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
4350 {
4351 ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx,
4352 p, end - p );
4353 if( ret != 0 )
4354 {
4355 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
4356 return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
4357 }
4358
4359 ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
4360 ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
4361 ssl->conf->f_rng, ssl->conf->p_rng );
4362 if( ret != 0 )
4363 {
4364 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
4365 return( ret );
4366 }
4367 }
4368 else
4369 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
4370 {
4371 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4372 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4373 }
4374
4375 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
4376 {
4377 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
4378 return( ret );
4379 }
4380
4381 ssl->state++;
4382
4383 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
4384
4385 return( 0 );
4386 }
4387
4388 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4389 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4390 {
4391 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4392 ssl->handshake->ciphersuite_info;
4393
4394 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4395
4396 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4397 {
4398 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4399 ssl->state++;
4400 return( 0 );
4401 }
4402
4403 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4404 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4405 }
4406 #else /* !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 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
4410 size_t i, sig_len;
4411 unsigned char hash[48];
4412 unsigned char *hash_start = hash;
4413 size_t hashlen;
4414 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4415 mbedtls_pk_type_t pk_alg;
4416 #endif
4417 mbedtls_md_type_t md_alg;
4418 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4419 ssl->handshake->ciphersuite_info;
4420 mbedtls_pk_context * peer_pk;
4421
4422 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4423
4424 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4425 {
4426 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4427 ssl->state++;
4428 return( 0 );
4429 }
4430
4431 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4432 if( ssl->session_negotiate->peer_cert == NULL )
4433 {
4434 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4435 ssl->state++;
4436 return( 0 );
4437 }
4438 #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4439 if( ssl->session_negotiate->peer_cert_digest == NULL )
4440 {
4441 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4442 ssl->state++;
4443 return( 0 );
4444 }
4445 #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4446
4447 /* Read the message without adding it to the checksum */
4448 ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
4449 if( 0 != ret )
4450 {
4451 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
4452 return( ret );
4453 }
4454
4455 ssl->state++;
4456
4457 /* Process the message contents */
4458 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
4459 ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY )
4460 {
4461 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4462 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4463 }
4464
4465 i = mbedtls_ssl_hs_hdr_len( ssl );
4466
4467 #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4468 peer_pk = &ssl->handshake->peer_pubkey;
4469 #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4470 if( ssl->session_negotiate->peer_cert == NULL )
4471 {
4472 /* Should never happen */
4473 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4474 }
4475 peer_pk = &ssl->session_negotiate->peer_cert->pk;
4476 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4477
4478 /*
4479 * struct {
4480 * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
4481 * opaque signature<0..2^16-1>;
4482 * } DigitallySigned;
4483 */
4484 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
4485 defined(MBEDTLS_SSL_PROTO_TLS1_1)
4486 if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 )
4487 {
4488 md_alg = MBEDTLS_MD_NONE;
4489 hashlen = 36;
4490
4491 /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
4492 if( mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECDSA ) )
4493 {
4494 hash_start += 16;
4495 hashlen -= 16;
4496 md_alg = MBEDTLS_MD_SHA1;
4497 }
4498 }
4499 else
4500 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 ||
4501 MBEDTLS_SSL_PROTO_TLS1_1 */
4502 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4503 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
4504 {
4505 if( i + 2 > ssl->in_hslen )
4506 {
4507 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4508 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4509 }
4510
4511 /*
4512 * Hash
4513 */
4514 md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] );
4515
4516 if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) )
4517 {
4518 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4519 " for verify message" ) );
4520 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4521 }
4522
4523 #if !defined(MBEDTLS_MD_SHA1)
4524 if( MBEDTLS_MD_SHA1 == md_alg )
4525 hash_start += 16;
4526 #endif
4527
4528 /* Info from md_alg will be used instead */
4529 hashlen = 0;
4530
4531 i++;
4532
4533 /*
4534 * Signature
4535 */
4536 if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) )
4537 == MBEDTLS_PK_NONE )
4538 {
4539 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4540 " for verify message" ) );
4541 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4542 }
4543
4544 /*
4545 * Check the certificate's key type matches the signature alg
4546 */
4547 if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
4548 {
4549 MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
4550 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4551 }
4552
4553 i++;
4554 }
4555 else
4556 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
4557 {
4558 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4559 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4560 }
4561
4562 if( i + 2 > ssl->in_hslen )
4563 {
4564 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4565 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4566 }
4567
4568 sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
4569 i += 2;
4570
4571 if( i + sig_len != ssl->in_hslen )
4572 {
4573 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4574 return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
4575 }
4576
4577 /* Calculate hash and verify signature */
4578 {
4579 size_t dummy_hlen;
4580 ssl->handshake->calc_verify( ssl, hash, &dummy_hlen );
4581 }
4582
4583 if( ( ret = mbedtls_pk_verify( peer_pk,
4584 md_alg, hash_start, hashlen,
4585 ssl->in_msg + i, sig_len ) ) != 0 )
4586 {
4587 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
4588 return( ret );
4589 }
4590
4591 mbedtls_ssl_update_handshake_status( ssl );
4592
4593 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
4594
4595 return( ret );
4596 }
4597 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
4598
4599 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_new_session_ticket(mbedtls_ssl_context * ssl)4600 static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
4601 {
4602 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4603 size_t tlen;
4604 uint32_t lifetime;
4605
4606 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
4607
4608 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
4609 ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
4610
4611 /*
4612 * struct {
4613 * uint32 ticket_lifetime_hint;
4614 * opaque ticket<0..2^16-1>;
4615 * } NewSessionTicket;
4616 *
4617 * 4 . 7 ticket_lifetime_hint (0 = unspecified)
4618 * 8 . 9 ticket_len (n)
4619 * 10 . 9+n ticket content
4620 */
4621
4622 if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
4623 ssl->session_negotiate,
4624 ssl->out_msg + 10,
4625 ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
4626 &tlen, &lifetime ) ) != 0 )
4627 {
4628 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
4629 tlen = 0;
4630 }
4631
4632 MBEDTLS_PUT_UINT32_BE( lifetime, ssl->out_msg, 4 );
4633 MBEDTLS_PUT_UINT16_BE( tlen, ssl->out_msg, 8 );
4634 ssl->out_msglen = 10 + tlen;
4635
4636 /*
4637 * Morally equivalent to updating ssl->state, but NewSessionTicket and
4638 * ChangeCipherSpec share the same state.
4639 */
4640 ssl->handshake->new_session_ticket = 0;
4641
4642 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
4643 {
4644 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
4645 return( ret );
4646 }
4647
4648 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
4649
4650 return( 0 );
4651 }
4652 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
4653
4654 /*
4655 * SSL handshake -- server side -- single step
4656 */
mbedtls_ssl_handshake_server_step(mbedtls_ssl_context * ssl)4657 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
4658 {
4659 int ret = 0;
4660
4661 if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
4662 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4663
4664 MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
4665
4666 if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
4667 return( ret );
4668
4669 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4670 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
4671 ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
4672 {
4673 if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
4674 return( ret );
4675 }
4676 #endif /* MBEDTLS_SSL_PROTO_DTLS */
4677
4678 switch( ssl->state )
4679 {
4680 case MBEDTLS_SSL_HELLO_REQUEST:
4681 ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
4682 break;
4683
4684 /*
4685 * <== ClientHello
4686 */
4687 case MBEDTLS_SSL_CLIENT_HELLO:
4688 ret = ssl_parse_client_hello( ssl );
4689 break;
4690
4691 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4692 case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
4693 return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
4694 #endif
4695
4696 /*
4697 * ==> ServerHello
4698 * Certificate
4699 * ( ServerKeyExchange )
4700 * ( CertificateRequest )
4701 * ServerHelloDone
4702 */
4703 case MBEDTLS_SSL_SERVER_HELLO:
4704 ret = ssl_write_server_hello( ssl );
4705 break;
4706
4707 case MBEDTLS_SSL_SERVER_CERTIFICATE:
4708 ret = mbedtls_ssl_write_certificate( ssl );
4709 break;
4710
4711 case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
4712 ret = ssl_write_server_key_exchange( ssl );
4713 break;
4714
4715 case MBEDTLS_SSL_CERTIFICATE_REQUEST:
4716 ret = ssl_write_certificate_request( ssl );
4717 break;
4718
4719 case MBEDTLS_SSL_SERVER_HELLO_DONE:
4720 ret = ssl_write_server_hello_done( ssl );
4721 break;
4722
4723 /*
4724 * <== ( Certificate/Alert )
4725 * ClientKeyExchange
4726 * ( CertificateVerify )
4727 * ChangeCipherSpec
4728 * Finished
4729 */
4730 case MBEDTLS_SSL_CLIENT_CERTIFICATE:
4731 ret = mbedtls_ssl_parse_certificate( ssl );
4732 break;
4733
4734 case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
4735 ret = ssl_parse_client_key_exchange( ssl );
4736 break;
4737
4738 case MBEDTLS_SSL_CERTIFICATE_VERIFY:
4739 ret = ssl_parse_certificate_verify( ssl );
4740 break;
4741
4742 case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
4743 ret = mbedtls_ssl_parse_change_cipher_spec( ssl );
4744 break;
4745
4746 case MBEDTLS_SSL_CLIENT_FINISHED:
4747 ret = mbedtls_ssl_parse_finished( ssl );
4748 break;
4749
4750 /*
4751 * ==> ( NewSessionTicket )
4752 * ChangeCipherSpec
4753 * Finished
4754 */
4755 case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
4756 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
4757 if( ssl->handshake->new_session_ticket != 0 )
4758 ret = ssl_write_new_session_ticket( ssl );
4759 else
4760 #endif
4761 ret = mbedtls_ssl_write_change_cipher_spec( ssl );
4762 break;
4763
4764 case MBEDTLS_SSL_SERVER_FINISHED:
4765 ret = mbedtls_ssl_write_finished( ssl );
4766 break;
4767
4768 case MBEDTLS_SSL_FLUSH_BUFFERS:
4769 MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
4770 ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
4771 break;
4772
4773 case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
4774 mbedtls_ssl_handshake_wrapup( ssl );
4775 break;
4776
4777 default:
4778 MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
4779 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4780 }
4781
4782 return( ret );
4783 }
4784 #endif /* MBEDTLS_SSL_SRV_C */
4785
