1 /*
2 * TLS 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 "ssl_misc.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_DECODE_ERROR );
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_DECODE_ERROR );
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_DECODE_ERROR );
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_UNRECOGNIZED_NAME );
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_DECODE_ERROR );
142 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
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_HANDSHAKE_FAILURE );
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_HANDSHAKE_FAILURE );
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_DECODE_ERROR );
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_DECODE_ERROR );
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_DECODE_ERROR );
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_DECODE_ERROR );
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_ILLEGAL_PARAMETER );
350 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
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_DECODE_ERROR );
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 mbedtls_ecjpake_set_point_format( &ssl->handshake->ecjpake_ctx,
413 p[0] );
414 #endif
415 MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
416 return( 0 );
417 }
418
419 list_size--;
420 p++;
421 }
422
423 return( 0 );
424 }
425 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
426 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
427
428 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_parse_ecjpake_kkpp(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)429 static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
430 const unsigned char *buf,
431 size_t len )
432 {
433 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
434
435 if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
436 {
437 MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip ecjpake kkpp extension" ) );
438 return( 0 );
439 }
440
441 if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx,
442 buf, len ) ) != 0 )
443 {
444 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
445 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
446 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
447 return( ret );
448 }
449
450 /* Only mark the extension as OK when we're sure it is */
451 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK;
452
453 return( 0 );
454 }
455 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
456
457 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_parse_max_fragment_length_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)458 static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
459 const unsigned char *buf,
460 size_t len )
461 {
462 if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID )
463 {
464 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
465 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
466 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
467 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
468 }
469
470 ssl->session_negotiate->mfl_code = buf[0];
471
472 return( 0 );
473 }
474 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
475
476 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_parse_cid_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)477 static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl,
478 const unsigned char *buf,
479 size_t len )
480 {
481 size_t peer_cid_len;
482
483 /* CID extension only makes sense in DTLS */
484 if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
485 {
486 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
487 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
488 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
489 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
490 }
491
492 /*
493 * Quoting draft-ietf-tls-dtls-connection-id-05
494 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
495 *
496 * struct {
497 * opaque cid<0..2^8-1>;
498 * } ConnectionId;
499 */
500
501 if( len < 1 )
502 {
503 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
504 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
505 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
506 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
507 }
508
509 peer_cid_len = *buf++;
510 len--;
511
512 if( len != peer_cid_len )
513 {
514 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
515 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
516 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
517 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
518 }
519
520 /* Ignore CID if the user has disabled its use. */
521 if( ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED )
522 {
523 /* Leave ssl->handshake->cid_in_use in its default
524 * value of MBEDTLS_SSL_CID_DISABLED. */
525 MBEDTLS_SSL_DEBUG_MSG( 3, ( "Client sent CID extension, but CID disabled" ) );
526 return( 0 );
527 }
528
529 if( peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX )
530 {
531 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
532 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
533 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
534 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
535 }
536
537 ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED;
538 ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len;
539 memcpy( ssl->handshake->peer_cid, buf, peer_cid_len );
540
541 MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use of CID extension negotiated" ) );
542 MBEDTLS_SSL_DEBUG_BUF( 3, "Client CID", buf, peer_cid_len );
543
544 return( 0 );
545 }
546 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
547
548 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_parse_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)549 static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
550 const unsigned char *buf,
551 size_t len )
552 {
553 if( len != 0 )
554 {
555 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
556 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
557 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
558 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
559 }
560
561 ((void) buf);
562
563 if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED )
564 {
565 ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED;
566 }
567
568 return( 0 );
569 }
570 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
571
572 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_parse_extended_ms_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)573 static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
574 const unsigned char *buf,
575 size_t len )
576 {
577 if( len != 0 )
578 {
579 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
580 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
581 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
582 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
583 }
584
585 ((void) buf);
586
587 if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED )
588 {
589 ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
590 }
591
592 return( 0 );
593 }
594 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
595
596 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_parse_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t len)597 static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
598 unsigned char *buf,
599 size_t len )
600 {
601 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
602 mbedtls_ssl_session session;
603
604 mbedtls_ssl_session_init( &session );
605
606 if( ssl->conf->f_ticket_parse == NULL ||
607 ssl->conf->f_ticket_write == NULL )
608 {
609 return( 0 );
610 }
611
612 /* Remember the client asked us to send a new ticket */
613 ssl->handshake->new_session_ticket = 1;
614
615 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %" MBEDTLS_PRINTF_SIZET, len ) );
616
617 if( len == 0 )
618 return( 0 );
619
620 #if defined(MBEDTLS_SSL_RENEGOTIATION)
621 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
622 {
623 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
624 return( 0 );
625 }
626 #endif /* MBEDTLS_SSL_RENEGOTIATION */
627
628 /*
629 * Failures are ok: just ignore the ticket and proceed.
630 */
631 if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session,
632 buf, len ) ) != 0 )
633 {
634 mbedtls_ssl_session_free( &session );
635
636 if( ret == MBEDTLS_ERR_SSL_INVALID_MAC )
637 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) );
638 else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED )
639 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) );
640 else
641 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
642
643 return( 0 );
644 }
645
646 /*
647 * Keep the session ID sent by the client, since we MUST send it back to
648 * inform them we're accepting the ticket (RFC 5077 section 3.4)
649 */
650 session.id_len = ssl->session_negotiate->id_len;
651 memcpy( &session.id, ssl->session_negotiate->id, session.id_len );
652
653 mbedtls_ssl_session_free( ssl->session_negotiate );
654 memcpy( ssl->session_negotiate, &session, sizeof( mbedtls_ssl_session ) );
655
656 /* Zeroize instead of free as we copied the content */
657 mbedtls_platform_zeroize( &session, sizeof( mbedtls_ssl_session ) );
658
659 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
660
661 ssl->handshake->resume = 1;
662
663 /* Don't send a new ticket after all, this one is OK */
664 ssl->handshake->new_session_ticket = 0;
665
666 return( 0 );
667 }
668 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
669
670 #if defined(MBEDTLS_SSL_ALPN)
ssl_parse_alpn_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)671 static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
672 const unsigned char *buf, size_t len )
673 {
674 size_t list_len, cur_len, ours_len;
675 const unsigned char *theirs, *start, *end;
676 const char **ours;
677
678 /* If ALPN not configured, just ignore the extension */
679 if( ssl->conf->alpn_list == NULL )
680 return( 0 );
681
682 /*
683 * opaque ProtocolName<1..2^8-1>;
684 *
685 * struct {
686 * ProtocolName protocol_name_list<2..2^16-1>
687 * } ProtocolNameList;
688 */
689
690 /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
691 if( len < 4 )
692 {
693 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
694 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
695 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
696 }
697
698 list_len = ( buf[0] << 8 ) | buf[1];
699 if( list_len != len - 2 )
700 {
701 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
702 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
703 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
704 }
705
706 /*
707 * Validate peer's list (lengths)
708 */
709 start = buf + 2;
710 end = buf + len;
711 for( theirs = start; theirs != end; theirs += cur_len )
712 {
713 cur_len = *theirs++;
714
715 /* Current identifier must fit in list */
716 if( cur_len > (size_t)( end - theirs ) )
717 {
718 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
719 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
720 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
721 }
722
723 /* Empty strings MUST NOT be included */
724 if( cur_len == 0 )
725 {
726 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
727 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
728 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
729 }
730 }
731
732 /*
733 * Use our order of preference
734 */
735 for( ours = ssl->conf->alpn_list; *ours != NULL; ours++ )
736 {
737 ours_len = strlen( *ours );
738 for( theirs = start; theirs != end; theirs += cur_len )
739 {
740 cur_len = *theirs++;
741
742 if( cur_len == ours_len &&
743 memcmp( theirs, *ours, cur_len ) == 0 )
744 {
745 ssl->alpn_chosen = *ours;
746 return( 0 );
747 }
748 }
749 }
750
751 /* If we get there, no match was found */
752 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
753 MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
754 return( MBEDTLS_ERR_SSL_NO_APPLICATION_PROTOCOL );
755 }
756 #endif /* MBEDTLS_SSL_ALPN */
757
758 #if defined(MBEDTLS_SSL_DTLS_SRTP)
ssl_parse_use_srtp_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t len)759 static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
760 const unsigned char *buf,
761 size_t len )
762 {
763 mbedtls_ssl_srtp_profile client_protection = MBEDTLS_TLS_SRTP_UNSET;
764 size_t i,j;
765 size_t profile_length;
766 uint16_t mki_length;
767 /*! 2 bytes for profile length and 1 byte for mki len */
768 const size_t size_of_lengths = 3;
769
770 /* If use_srtp is not configured, just ignore the extension */
771 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
772 ( ssl->conf->dtls_srtp_profile_list == NULL ) ||
773 ( ssl->conf->dtls_srtp_profile_list_len == 0 ) )
774 {
775 return( 0 );
776 }
777
778 /* RFC5764 section 4.1.1
779 * uint8 SRTPProtectionProfile[2];
780 *
781 * struct {
782 * SRTPProtectionProfiles SRTPProtectionProfiles;
783 * opaque srtp_mki<0..255>;
784 * } UseSRTPData;
785
786 * SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>;
787 */
788
789 /*
790 * Min length is 5: at least one protection profile(2 bytes)
791 * and length(2 bytes) + srtp_mki length(1 byte)
792 * Check here that we have at least 2 bytes of protection profiles length
793 * and one of srtp_mki length
794 */
795 if( len < size_of_lengths )
796 {
797 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
798 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
799 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
800 }
801
802 ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_TLS_SRTP_UNSET;
803
804 /* first 2 bytes are protection profile length(in bytes) */
805 profile_length = ( buf[0] << 8 ) | buf[1];
806 buf += 2;
807
808 /* The profile length cannot be bigger than input buffer size - lengths fields */
809 if( profile_length > len - size_of_lengths ||
810 profile_length % 2 != 0 ) /* profiles are 2 bytes long, so the length must be even */
811 {
812 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
813 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
814 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
815 }
816 /*
817 * parse the extension list values are defined in
818 * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
819 */
820 for( j = 0; j < profile_length; j += 2 )
821 {
822 uint16_t protection_profile_value = buf[j] << 8 | buf[j + 1];
823 client_protection = mbedtls_ssl_check_srtp_profile_value( protection_profile_value );
824
825 if( client_protection != MBEDTLS_TLS_SRTP_UNSET )
826 {
827 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found srtp profile: %s",
828 mbedtls_ssl_get_srtp_profile_as_string(
829 client_protection ) ) );
830 }
831 else
832 {
833 continue;
834 }
835 /* check if suggested profile is in our list */
836 for( i = 0; i < ssl->conf->dtls_srtp_profile_list_len; i++)
837 {
838 if( client_protection == ssl->conf->dtls_srtp_profile_list[i] )
839 {
840 ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i];
841 MBEDTLS_SSL_DEBUG_MSG( 3, ( "selected srtp profile: %s",
842 mbedtls_ssl_get_srtp_profile_as_string(
843 client_protection ) ) );
844 break;
845 }
846 }
847 if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_TLS_SRTP_UNSET )
848 break;
849 }
850 buf += profile_length; /* buf points to the mki length */
851 mki_length = *buf;
852 buf++;
853
854 if( mki_length > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH ||
855 mki_length + profile_length + size_of_lengths != len )
856 {
857 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
858 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
859 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
860 }
861
862 /* Parse the mki only if present and mki is supported locally */
863 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED &&
864 mki_length > 0 )
865 {
866 ssl->dtls_srtp_info.mki_len = mki_length;
867
868 memcpy( ssl->dtls_srtp_info.mki_value, buf, mki_length );
869
870 MBEDTLS_SSL_DEBUG_BUF( 3, "using mki", ssl->dtls_srtp_info.mki_value,
871 ssl->dtls_srtp_info.mki_len );
872 }
873
874 return( 0 );
875 }
876 #endif /* MBEDTLS_SSL_DTLS_SRTP */
877
878 /*
879 * Auxiliary functions for ServerHello parsing and related actions
880 */
881
882 #if defined(MBEDTLS_X509_CRT_PARSE_C)
883 /*
884 * Return 0 if the given key uses one of the acceptable curves, -1 otherwise
885 */
886 #if defined(MBEDTLS_ECDSA_C)
ssl_check_key_curve(mbedtls_pk_context * pk,const mbedtls_ecp_curve_info ** curves)887 static int ssl_check_key_curve( mbedtls_pk_context *pk,
888 const mbedtls_ecp_curve_info **curves )
889 {
890 const mbedtls_ecp_curve_info **crv = curves;
891 mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id;
892
893 while( *crv != NULL )
894 {
895 if( (*crv)->grp_id == grp_id )
896 return( 0 );
897 crv++;
898 }
899
900 return( -1 );
901 }
902 #endif /* MBEDTLS_ECDSA_C */
903
904 /*
905 * Try picking a certificate for this ciphersuite,
906 * return 0 on success and -1 on failure.
907 */
ssl_pick_cert(mbedtls_ssl_context * ssl,const mbedtls_ssl_ciphersuite_t * ciphersuite_info)908 static int ssl_pick_cert( mbedtls_ssl_context *ssl,
909 const mbedtls_ssl_ciphersuite_t * ciphersuite_info )
910 {
911 mbedtls_ssl_key_cert *cur, *list, *fallback = NULL;
912 mbedtls_pk_type_t pk_alg =
913 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
914 uint32_t flags;
915
916 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
917 if( ssl->handshake->sni_key_cert != NULL )
918 list = ssl->handshake->sni_key_cert;
919 else
920 #endif
921 list = ssl->conf->key_cert;
922
923 if( pk_alg == MBEDTLS_PK_NONE )
924 return( 0 );
925
926 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) );
927
928 if( list == NULL )
929 {
930 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server has no certificate" ) );
931 return( -1 );
932 }
933
934 for( cur = list; cur != NULL; cur = cur->next )
935 {
936 flags = 0;
937 MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
938 cur->cert );
939
940 if( ! mbedtls_pk_can_do( &cur->cert->pk, pk_alg ) )
941 {
942 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) );
943 continue;
944 }
945
946 /*
947 * This avoids sending the client a cert it'll reject based on
948 * keyUsage or other extensions.
949 *
950 * It also allows the user to provision different certificates for
951 * different uses based on keyUsage, eg if they want to avoid signing
952 * and decrypting with the same RSA key.
953 */
954 if( mbedtls_ssl_check_cert_usage( cur->cert, ciphersuite_info,
955 MBEDTLS_SSL_IS_SERVER, &flags ) != 0 )
956 {
957 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
958 "(extended) key usage extension" ) );
959 continue;
960 }
961
962 #if defined(MBEDTLS_ECDSA_C)
963 if( pk_alg == MBEDTLS_PK_ECDSA &&
964 ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 0 )
965 {
966 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) );
967 continue;
968 }
969 #endif
970
971 /*
972 * Try to select a SHA-1 certificate for pre-1.2 clients, but still
973 * present them a SHA-higher cert rather than failing if it's the only
974 * one we got that satisfies the other conditions.
975 */
976 if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 &&
977 cur->cert->sig_md != MBEDTLS_MD_SHA1 )
978 {
979 if( fallback == NULL )
980 fallback = cur;
981 {
982 MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate not preferred: "
983 "sha-2 with pre-TLS 1.2 client" ) );
984 continue;
985 }
986 }
987
988 /* If we get there, we got a winner */
989 break;
990 }
991
992 if( cur == NULL )
993 cur = fallback;
994
995 /* Do not update ssl->handshake->key_cert unless there is a match */
996 if( cur != NULL )
997 {
998 ssl->handshake->key_cert = cur;
999 MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
1000 ssl->handshake->key_cert->cert );
1001 return( 0 );
1002 }
1003
1004 return( -1 );
1005 }
1006 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1007
1008 /*
1009 * Check if a given ciphersuite is suitable for use with our config/keys/etc
1010 * Sets ciphersuite_info only if the suite matches.
1011 */
ssl_ciphersuite_match(mbedtls_ssl_context * ssl,int suite_id,const mbedtls_ssl_ciphersuite_t ** ciphersuite_info)1012 static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id,
1013 const mbedtls_ssl_ciphersuite_t **ciphersuite_info )
1014 {
1015 const mbedtls_ssl_ciphersuite_t *suite_info;
1016
1017 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1018 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1019 mbedtls_pk_type_t sig_type;
1020 #endif
1021
1022 suite_info = mbedtls_ssl_ciphersuite_from_id( suite_id );
1023 if( suite_info == NULL )
1024 {
1025 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
1026 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
1027 }
1028
1029 MBEDTLS_SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %#04x (%s)",
1030 (unsigned int) suite_id, suite_info->name ) );
1031
1032 if( suite_info->min_minor_ver > ssl->minor_ver ||
1033 suite_info->max_minor_ver < ssl->minor_ver )
1034 {
1035 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) );
1036 return( 0 );
1037 }
1038
1039 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1040 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
1041 ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
1042 return( 0 );
1043 #endif
1044
1045 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1046 if( suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
1047 ( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK ) == 0 )
1048 {
1049 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: ecjpake "
1050 "not configured or ext missing" ) );
1051 return( 0 );
1052 }
1053 #endif
1054
1055
1056 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
1057 if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) &&
1058 ( ssl->handshake->curves == NULL ||
1059 ssl->handshake->curves[0] == NULL ) )
1060 {
1061 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
1062 "no common elliptic curve" ) );
1063 return( 0 );
1064 }
1065 #endif
1066
1067 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
1068 /* If the ciphersuite requires a pre-shared key and we don't
1069 * have one, skip it now rather than failing later */
1070 if( mbedtls_ssl_ciphersuite_uses_psk( suite_info ) &&
1071 ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
1072 {
1073 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) );
1074 return( 0 );
1075 }
1076 #endif
1077
1078 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1079 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1080 /* If the ciphersuite requires signing, check whether
1081 * a suitable hash algorithm is present. */
1082 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
1083 {
1084 sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
1085 if( sig_type != MBEDTLS_PK_NONE &&
1086 mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == MBEDTLS_MD_NONE )
1087 {
1088 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
1089 "for signature algorithm %u", (unsigned) sig_type ) );
1090 return( 0 );
1091 }
1092 }
1093
1094 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1095 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1096
1097 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1098 /*
1099 * Final check: if ciphersuite requires us to have a
1100 * certificate/key of a particular type:
1101 * - select the appropriate certificate if we have one, or
1102 * - try the next ciphersuite if we don't
1103 * This must be done last since we modify the key_cert list.
1104 */
1105 if( ssl_pick_cert( ssl, suite_info ) != 0 )
1106 {
1107 MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
1108 "no suitable certificate" ) );
1109 return( 0 );
1110 }
1111 #endif
1112
1113 *ciphersuite_info = suite_info;
1114 return( 0 );
1115 }
1116
1117 /* This function doesn't alert on errors that happen early during
1118 ClientHello parsing because they might indicate that the client is
1119 not talking SSL/TLS at all and would not understand our alert. */
ssl_parse_client_hello(mbedtls_ssl_context * ssl)1120 static int ssl_parse_client_hello( mbedtls_ssl_context *ssl )
1121 {
1122 int ret, got_common_suite;
1123 size_t i, j;
1124 size_t ciph_offset, comp_offset, ext_offset;
1125 size_t msg_len, ciph_len, sess_len, comp_len, ext_len;
1126 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1127 size_t cookie_offset, cookie_len;
1128 #endif
1129 unsigned char *buf, *p, *ext;
1130 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1131 int renegotiation_info_seen = 0;
1132 #endif
1133 int handshake_failure = 0;
1134 const int *ciphersuites;
1135 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
1136 int major, minor;
1137
1138 /* If there is no signature-algorithm extension present,
1139 * we need to fall back to the default values for allowed
1140 * signature-hash pairs. */
1141 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1142 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1143 int sig_hash_alg_ext_present = 0;
1144 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1145 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1146
1147 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
1148
1149 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1150 read_record_header:
1151 #endif
1152 /*
1153 * If renegotiating, then the input was read with mbedtls_ssl_read_record(),
1154 * otherwise read it ourselves manually in order to support SSLv2
1155 * ClientHello, which doesn't use the same record layer format.
1156 */
1157 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1158 if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
1159 #endif
1160 {
1161 if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
1162 {
1163 /* No alert on a read error. */
1164 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1165 return( ret );
1166 }
1167 }
1168
1169 buf = ssl->in_hdr;
1170
1171 MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_in_hdr_len( ssl ) );
1172
1173 /*
1174 * TLS Client Hello
1175 *
1176 * Record layer:
1177 * 0 . 0 message type
1178 * 1 . 2 protocol version
1179 * 3 . 11 DTLS: epoch + record sequence number
1180 * 3 . 4 message length
1181 */
1182 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, message type: %d",
1183 buf[0] ) );
1184
1185 if( buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE )
1186 {
1187 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1188 return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
1189 }
1190
1191 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, message len.: %d",
1192 ( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) );
1193
1194 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, protocol version: [%d:%d]",
1195 buf[1], buf[2] ) );
1196
1197 mbedtls_ssl_read_version( &major, &minor, ssl->conf->transport, buf + 1 );
1198
1199 /* According to RFC 5246 Appendix E.1, the version here is typically
1200 * "{03,00}, the lowest version number supported by the client, [or] the
1201 * value of ClientHello.client_version", so the only meaningful check here
1202 * is the major version shouldn't be less than 3 */
1203 if( major < MBEDTLS_SSL_MAJOR_VERSION_3 )
1204 {
1205 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1206 return( MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION );
1207 }
1208
1209 /* For DTLS if this is the initial handshake, remember the client sequence
1210 * number to use it in our next message (RFC 6347 4.2.1) */
1211 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1212 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM
1213 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1214 && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
1215 #endif
1216 )
1217 {
1218 /* Epoch should be 0 for initial handshakes */
1219 if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 )
1220 {
1221 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1222 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
1223 }
1224
1225 memcpy( &ssl->cur_out_ctr[2], ssl->in_ctr + 2,
1226 sizeof( ssl->cur_out_ctr ) - 2 );
1227
1228 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1229 if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
1230 {
1231 MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record, discarding" ) );
1232 ssl->next_record_offset = 0;
1233 ssl->in_left = 0;
1234 goto read_record_header;
1235 }
1236
1237 /* No MAC to check yet, so we can update right now */
1238 mbedtls_ssl_dtls_replay_update( ssl );
1239 #endif
1240 }
1241 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1242
1243 msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1];
1244
1245 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1246 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
1247 {
1248 /* Set by mbedtls_ssl_read_record() */
1249 msg_len = ssl->in_hslen;
1250 }
1251 else
1252 #endif
1253 {
1254 if( msg_len > MBEDTLS_SSL_IN_CONTENT_LEN )
1255 {
1256 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1257 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
1258 }
1259
1260 if( ( ret = mbedtls_ssl_fetch_input( ssl,
1261 mbedtls_ssl_in_hdr_len( ssl ) + msg_len ) ) != 0 )
1262 {
1263 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
1264 return( ret );
1265 }
1266
1267 /* Done reading this record, get ready for the next one */
1268 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1269 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1270 ssl->next_record_offset = msg_len + mbedtls_ssl_in_hdr_len( ssl );
1271 else
1272 #endif
1273 ssl->in_left = 0;
1274 }
1275
1276 buf = ssl->in_msg;
1277
1278 MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, msg_len );
1279
1280 ssl->handshake->update_checksum( ssl, buf, msg_len );
1281
1282 /*
1283 * Handshake layer:
1284 * 0 . 0 handshake type
1285 * 1 . 3 handshake length
1286 * 4 . 5 DTLS only: message seqence number
1287 * 6 . 8 DTLS only: fragment offset
1288 * 9 . 11 DTLS only: fragment length
1289 */
1290 if( msg_len < mbedtls_ssl_hs_hdr_len( ssl ) )
1291 {
1292 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1293 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1294 }
1295
1296 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
1297
1298 if( buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO )
1299 {
1300 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1301 return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
1302 }
1303
1304 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
1305 ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
1306
1307 /* We don't support fragmentation of ClientHello (yet?) */
1308 if( buf[1] != 0 ||
1309 msg_len != mbedtls_ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) )
1310 {
1311 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1312 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1313 }
1314
1315 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1316 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1317 {
1318 /*
1319 * Copy the client's handshake message_seq on initial handshakes,
1320 * check sequence number on renego.
1321 */
1322 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1323 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1324 {
1325 /* This couldn't be done in ssl_prepare_handshake_record() */
1326 unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
1327 ssl->in_msg[5];
1328
1329 if( cli_msg_seq != ssl->handshake->in_msg_seq )
1330 {
1331 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message_seq: "
1332 "%u (expected %u)", cli_msg_seq,
1333 ssl->handshake->in_msg_seq ) );
1334 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1335 }
1336
1337 ssl->handshake->in_msg_seq++;
1338 }
1339 else
1340 #endif
1341 {
1342 unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
1343 ssl->in_msg[5];
1344 ssl->handshake->out_msg_seq = cli_msg_seq;
1345 ssl->handshake->in_msg_seq = cli_msg_seq + 1;
1346 }
1347
1348 /*
1349 * For now we don't support fragmentation, so make sure
1350 * fragment_offset == 0 and fragment_length == length
1351 */
1352 if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
1353 memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
1354 {
1355 MBEDTLS_SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) );
1356 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
1357 }
1358 }
1359 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1360
1361 buf += mbedtls_ssl_hs_hdr_len( ssl );
1362 msg_len -= mbedtls_ssl_hs_hdr_len( ssl );
1363
1364 /*
1365 * ClientHello layer:
1366 * 0 . 1 protocol version
1367 * 2 . 33 random bytes (starting with 4 bytes of Unix time)
1368 * 34 . 35 session id length (1 byte)
1369 * 35 . 34+x session id
1370 * 35+x . 35+x DTLS only: cookie length (1 byte)
1371 * 36+x . .. DTLS only: cookie
1372 * .. . .. ciphersuite list length (2 bytes)
1373 * .. . .. ciphersuite list
1374 * .. . .. compression alg. list length (1 byte)
1375 * .. . .. compression alg. list
1376 * .. . .. extensions length (2 bytes, optional)
1377 * .. . .. extensions (optional)
1378 */
1379
1380 /*
1381 * Minimal length (with everything empty and extensions omitted) is
1382 * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
1383 * read at least up to session id length without worrying.
1384 */
1385 if( msg_len < 38 )
1386 {
1387 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1388 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1389 }
1390
1391 /*
1392 * Check and save the protocol version
1393 */
1394 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 );
1395
1396 mbedtls_ssl_read_version( &ssl->major_ver, &ssl->minor_ver,
1397 ssl->conf->transport, buf );
1398 ssl->session_negotiate->minor_ver = ssl->minor_ver;
1399
1400 ssl->handshake->max_major_ver = ssl->major_ver;
1401 ssl->handshake->max_minor_ver = ssl->minor_ver;
1402
1403 if( ssl->major_ver < ssl->conf->min_major_ver ||
1404 ssl->minor_ver < ssl->conf->min_minor_ver )
1405 {
1406 MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
1407 " [%d:%d] < [%d:%d]",
1408 ssl->major_ver, ssl->minor_ver,
1409 ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
1410 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1411 MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
1412 return( MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION );
1413 }
1414
1415 if( ssl->major_ver > ssl->conf->max_major_ver )
1416 {
1417 ssl->major_ver = ssl->conf->max_major_ver;
1418 ssl->minor_ver = ssl->conf->max_minor_ver;
1419 }
1420 else if( ssl->minor_ver > ssl->conf->max_minor_ver )
1421 ssl->minor_ver = ssl->conf->max_minor_ver;
1422
1423 /*
1424 * Save client random (inc. Unix time)
1425 */
1426 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 );
1427
1428 memcpy( ssl->handshake->randbytes, buf + 2, 32 );
1429
1430 /*
1431 * Check the session ID length and save session ID
1432 */
1433 sess_len = buf[34];
1434
1435 if( sess_len > sizeof( ssl->session_negotiate->id ) ||
1436 sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */
1437 {
1438 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1439 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1440 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1441 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1442 }
1443
1444 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len );
1445
1446 ssl->session_negotiate->id_len = sess_len;
1447 memset( ssl->session_negotiate->id, 0,
1448 sizeof( ssl->session_negotiate->id ) );
1449 memcpy( ssl->session_negotiate->id, buf + 35,
1450 ssl->session_negotiate->id_len );
1451
1452 /*
1453 * Check the cookie length and content
1454 */
1455 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1456 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1457 {
1458 cookie_offset = 35 + sess_len;
1459 cookie_len = buf[cookie_offset];
1460
1461 if( cookie_offset + 1 + cookie_len + 2 > msg_len )
1462 {
1463 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1464 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1465 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1466 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1467 }
1468
1469 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie",
1470 buf + cookie_offset + 1, cookie_len );
1471
1472 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
1473 if( ssl->conf->f_cookie_check != NULL
1474 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1475 && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
1476 #endif
1477 )
1478 {
1479 if( ssl->conf->f_cookie_check( ssl->conf->p_cookie,
1480 buf + cookie_offset + 1, cookie_len,
1481 ssl->cli_id, ssl->cli_id_len ) != 0 )
1482 {
1483 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification failed" ) );
1484 ssl->handshake->verify_cookie_len = 1;
1485 }
1486 else
1487 {
1488 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) );
1489 ssl->handshake->verify_cookie_len = 0;
1490 }
1491 }
1492 else
1493 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
1494 {
1495 /* We know we didn't send a cookie, so it should be empty */
1496 if( cookie_len != 0 )
1497 {
1498 /* This may be an attacker's probe, so don't send an alert */
1499 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1500 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1501 }
1502
1503 MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification skipped" ) );
1504 }
1505
1506 /*
1507 * Check the ciphersuitelist length (will be parsed later)
1508 */
1509 ciph_offset = cookie_offset + 1 + cookie_len;
1510 }
1511 else
1512 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1513 ciph_offset = 35 + sess_len;
1514
1515 ciph_len = ( buf[ciph_offset + 0] << 8 )
1516 | ( buf[ciph_offset + 1] );
1517
1518 if( ciph_len < 2 ||
1519 ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
1520 ( ciph_len % 2 ) != 0 )
1521 {
1522 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1523 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1524 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1525 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1526 }
1527
1528 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
1529 buf + ciph_offset + 2, ciph_len );
1530
1531 /*
1532 * Check the compression algorithms length and pick one
1533 */
1534 comp_offset = ciph_offset + 2 + ciph_len;
1535
1536 comp_len = buf[comp_offset];
1537
1538 if( comp_len < 1 ||
1539 comp_len > 16 ||
1540 comp_len + comp_offset + 1 > msg_len )
1541 {
1542 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1543 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1544 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1545 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1546 }
1547
1548 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, compression",
1549 buf + comp_offset + 1, comp_len );
1550
1551 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
1552 /* See comments in ssl_write_client_hello() */
1553 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1554 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1555 ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
1556 #endif
1557 /*
1558 * Check the extension length
1559 */
1560 ext_offset = comp_offset + 1 + comp_len;
1561 if( msg_len > ext_offset )
1562 {
1563 if( msg_len < ext_offset + 2 )
1564 {
1565 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1566 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1567 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1568 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1569 }
1570
1571 ext_len = ( buf[ext_offset + 0] << 8 )
1572 | ( buf[ext_offset + 1] );
1573
1574 if( msg_len != ext_offset + 2 + ext_len )
1575 {
1576 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1577 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1578 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1579 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1580 }
1581 }
1582 else
1583 ext_len = 0;
1584
1585 ext = buf + ext_offset + 2;
1586 MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len );
1587
1588 while( ext_len != 0 )
1589 {
1590 unsigned int ext_id;
1591 unsigned int ext_size;
1592 if ( ext_len < 4 ) {
1593 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1594 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1595 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1596 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1597 }
1598 ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) );
1599 ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) );
1600
1601 if( ext_size + 4 > ext_len )
1602 {
1603 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
1604 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1605 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
1606 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
1607 }
1608 switch( ext_id )
1609 {
1610 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
1611 case MBEDTLS_TLS_EXT_SERVERNAME:
1612 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
1613 if( ssl->conf->f_sni == NULL )
1614 break;
1615
1616 ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size );
1617 if( ret != 0 )
1618 return( ret );
1619 break;
1620 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
1621
1622 case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO:
1623 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
1624 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1625 renegotiation_info_seen = 1;
1626 #endif
1627
1628 ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
1629 if( ret != 0 )
1630 return( ret );
1631 break;
1632
1633 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1634 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1635 case MBEDTLS_TLS_EXT_SIG_ALG:
1636 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
1637
1638 ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
1639 if( ret != 0 )
1640 return( ret );
1641
1642 sig_hash_alg_ext_present = 1;
1643 break;
1644 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1645 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1646
1647 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
1648 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1649 case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
1650 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
1651
1652 ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
1653 if( ret != 0 )
1654 return( ret );
1655 break;
1656
1657 case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS:
1658 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) );
1659 ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
1660
1661 ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size );
1662 if( ret != 0 )
1663 return( ret );
1664 break;
1665 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
1666 MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1667
1668 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1669 case MBEDTLS_TLS_EXT_ECJPAKE_KKPP:
1670 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ecjpake kkpp extension" ) );
1671
1672 ret = ssl_parse_ecjpake_kkpp( ssl, ext + 4, ext_size );
1673 if( ret != 0 )
1674 return( ret );
1675 break;
1676 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1677
1678 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
1679 case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH:
1680 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
1681
1682 ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size );
1683 if( ret != 0 )
1684 return( ret );
1685 break;
1686 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
1687
1688 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
1689 case MBEDTLS_TLS_EXT_CID:
1690 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found CID extension" ) );
1691
1692 ret = ssl_parse_cid_ext( ssl, ext + 4, ext_size );
1693 if( ret != 0 )
1694 return( ret );
1695 break;
1696 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1697
1698 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
1699 case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
1700 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
1701
1702 ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
1703 if( ret != 0 )
1704 return( ret );
1705 break;
1706 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
1707
1708 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
1709 case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET:
1710 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
1711
1712 ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size );
1713 if( ret != 0 )
1714 return( ret );
1715 break;
1716 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
1717
1718 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
1719 case MBEDTLS_TLS_EXT_SESSION_TICKET:
1720 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) );
1721
1722 ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size );
1723 if( ret != 0 )
1724 return( ret );
1725 break;
1726 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
1727
1728 #if defined(MBEDTLS_SSL_ALPN)
1729 case MBEDTLS_TLS_EXT_ALPN:
1730 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );
1731
1732 ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
1733 if( ret != 0 )
1734 return( ret );
1735 break;
1736 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
1737
1738 #if defined(MBEDTLS_SSL_DTLS_SRTP)
1739 case MBEDTLS_TLS_EXT_USE_SRTP:
1740 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found use_srtp extension" ) );
1741
1742 ret = ssl_parse_use_srtp_ext( ssl, ext + 4, ext_size );
1743 if( ret != 0 )
1744 return( ret );
1745 break;
1746 #endif /* MBEDTLS_SSL_DTLS_SRTP */
1747
1748 default:
1749 MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %u (ignoring)",
1750 ext_id ) );
1751 }
1752
1753 ext_len -= 4 + ext_size;
1754 ext += 4 + ext_size;
1755 }
1756
1757 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1758 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1759
1760 /*
1761 * Try to fall back to default hash SHA1 if the client
1762 * hasn't provided any preferred signature-hash combinations.
1763 */
1764 if( sig_hash_alg_ext_present == 0 )
1765 {
1766 mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1;
1767
1768 if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 )
1769 md_default = MBEDTLS_MD_NONE;
1770
1771 mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default );
1772 }
1773
1774 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
1775 MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
1776
1777 /*
1778 * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
1779 */
1780 for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
1781 {
1782 if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
1783 {
1784 MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
1785 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1786 if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
1787 {
1788 MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
1789 "during renegotiation" ) );
1790 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1791 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1792 return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
1793 }
1794 #endif
1795 ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
1796 break;
1797 }
1798 }
1799
1800 /*
1801 * Renegotiation security checks
1802 */
1803 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
1804 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
1805 {
1806 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
1807 handshake_failure = 1;
1808 }
1809 #if defined(MBEDTLS_SSL_RENEGOTIATION)
1810 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
1811 ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
1812 renegotiation_info_seen == 0 )
1813 {
1814 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
1815 handshake_failure = 1;
1816 }
1817 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
1818 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
1819 ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION )
1820 {
1821 MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
1822 handshake_failure = 1;
1823 }
1824 else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
1825 ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
1826 renegotiation_info_seen == 1 )
1827 {
1828 MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
1829 handshake_failure = 1;
1830 }
1831 #endif /* MBEDTLS_SSL_RENEGOTIATION */
1832
1833 if( handshake_failure == 1 )
1834 {
1835 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1836 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1837 return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
1838 }
1839
1840 /*
1841 * Search for a matching ciphersuite
1842 * (At the end because we need information from the EC-based extensions
1843 * and certificate from the SNI callback triggered by the SNI extension.)
1844 */
1845 got_common_suite = 0;
1846 ciphersuites = ssl->conf->ciphersuite_list;
1847 ciphersuite_info = NULL;
1848
1849 if (ssl->conf->respect_cli_pref == MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_CLIENT)
1850 {
1851 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
1852 for( i = 0; ciphersuites[i] != 0; i++ )
1853 {
1854 if( MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i] )
1855 continue;
1856
1857 got_common_suite = 1;
1858
1859 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
1860 &ciphersuite_info ) ) != 0 )
1861 return( ret );
1862
1863 if( ciphersuite_info != NULL )
1864 goto have_ciphersuite;
1865 }
1866 } else {
1867 for( i = 0; ciphersuites[i] != 0; i++ )
1868 for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
1869 {
1870 if( MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i] )
1871 continue;
1872
1873 got_common_suite = 1;
1874
1875 if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
1876 &ciphersuite_info ) ) != 0 )
1877 return( ret );
1878
1879 if( ciphersuite_info != NULL )
1880 goto have_ciphersuite;
1881 }
1882 }
1883
1884 if( got_common_suite )
1885 {
1886 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
1887 "but none of them usable" ) );
1888 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1889 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1890 return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
1891 }
1892 else
1893 {
1894 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
1895 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
1896 MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
1897 return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
1898 }
1899
1900 have_ciphersuite:
1901 MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
1902
1903 ssl->session_negotiate->ciphersuite = ciphersuites[i];
1904 ssl->handshake->ciphersuite_info = ciphersuite_info;
1905
1906 ssl->state++;
1907
1908 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1909 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
1910 mbedtls_ssl_recv_flight_completed( ssl );
1911 #endif
1912
1913 /* Debugging-only output for testsuite */
1914 #if defined(MBEDTLS_DEBUG_C) && \
1915 defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
1916 defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
1917 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
1918 {
1919 mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info );
1920 if( sig_alg != MBEDTLS_PK_NONE )
1921 {
1922 mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
1923 sig_alg );
1924 MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
1925 mbedtls_ssl_hash_from_md_alg( md_alg ) ) );
1926 }
1927 else
1928 {
1929 MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm "
1930 "%u - should not happen", (unsigned) sig_alg ) );
1931 }
1932 }
1933 #endif
1934
1935 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
1936
1937 return( 0 );
1938 }
1939
1940 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_write_cid_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)1941 static void ssl_write_cid_ext( mbedtls_ssl_context *ssl,
1942 unsigned char *buf,
1943 size_t *olen )
1944 {
1945 unsigned char *p = buf;
1946 size_t ext_len;
1947 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
1948
1949 *olen = 0;
1950
1951 /* Skip writing the extension if we don't want to use it or if
1952 * the client hasn't offered it. */
1953 if( ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED )
1954 return;
1955
1956 /* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX
1957 * which is at most 255, so the increment cannot overflow. */
1958 if( end < p || (size_t)( end - p ) < (unsigned)( ssl->own_cid_len + 5 ) )
1959 {
1960 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
1961 return;
1962 }
1963
1964 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding CID extension" ) );
1965
1966 /*
1967 * Quoting draft-ietf-tls-dtls-connection-id-05
1968 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
1969 *
1970 * struct {
1971 * opaque cid<0..2^8-1>;
1972 * } ConnectionId;
1973 */
1974 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_CID, p, 0 );
1975 p += 2;
1976 ext_len = (size_t) ssl->own_cid_len + 1;
1977 MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
1978 p += 2;
1979
1980 *p++ = (uint8_t) ssl->own_cid_len;
1981 memcpy( p, ssl->own_cid, ssl->own_cid_len );
1982
1983 *olen = ssl->own_cid_len + 5;
1984 }
1985 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
1986
1987 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)1988 static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
1989 unsigned char *buf,
1990 size_t *olen )
1991 {
1992 unsigned char *p = buf;
1993 const mbedtls_ssl_ciphersuite_t *suite = NULL;
1994 const mbedtls_cipher_info_t *cipher = NULL;
1995
1996 if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED )
1997 {
1998 *olen = 0;
1999 return;
2000 }
2001
2002 /*
2003 * RFC 7366: "If a server receives an encrypt-then-MAC request extension
2004 * from a client and then selects a stream or Authenticated Encryption
2005 * with Associated Data (AEAD) ciphersuite, it MUST NOT send an
2006 * encrypt-then-MAC response extension back to the client."
2007 */
2008 if( ( suite = mbedtls_ssl_ciphersuite_from_id(
2009 ssl->session_negotiate->ciphersuite ) ) == NULL ||
2010 ( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL ||
2011 cipher->mode != MBEDTLS_MODE_CBC )
2012 {
2013 *olen = 0;
2014 return;
2015 }
2016
2017 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
2018
2019 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC, p, 0 );
2020 p += 2;
2021
2022 *p++ = 0x00;
2023 *p++ = 0x00;
2024
2025 *olen = 4;
2026 }
2027 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2028
2029 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2030 static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
2031 unsigned char *buf,
2032 size_t *olen )
2033 {
2034 unsigned char *p = buf;
2035
2036 if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED )
2037 {
2038 *olen = 0;
2039 return;
2040 }
2041
2042 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
2043 "extension" ) );
2044
2045 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET, p, 0 );
2046 p += 2;
2047
2048 *p++ = 0x00;
2049 *p++ = 0x00;
2050
2051 *olen = 4;
2052 }
2053 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2054
2055 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2056 static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
2057 unsigned char *buf,
2058 size_t *olen )
2059 {
2060 unsigned char *p = buf;
2061
2062 if( ssl->handshake->new_session_ticket == 0 )
2063 {
2064 *olen = 0;
2065 return;
2066 }
2067
2068 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
2069
2070 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SESSION_TICKET, p, 0 );
2071 p += 2;
2072
2073 *p++ = 0x00;
2074 *p++ = 0x00;
2075
2076 *olen = 4;
2077 }
2078 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2079
ssl_write_renegotiation_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2080 static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
2081 unsigned char *buf,
2082 size_t *olen )
2083 {
2084 unsigned char *p = buf;
2085
2086 if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION )
2087 {
2088 *olen = 0;
2089 return;
2090 }
2091
2092 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) );
2093
2094 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO, p, 0 );
2095 p += 2;
2096
2097 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2098 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2099 {
2100 *p++ = 0x00;
2101 *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF;
2102 *p++ = ssl->verify_data_len * 2 & 0xFF;
2103
2104 memcpy( p, ssl->peer_verify_data, ssl->verify_data_len );
2105 p += ssl->verify_data_len;
2106 memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
2107 p += ssl->verify_data_len;
2108 }
2109 else
2110 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2111 {
2112 *p++ = 0x00;
2113 *p++ = 0x01;
2114 *p++ = 0x00;
2115 }
2116
2117 *olen = p - buf;
2118 }
2119
2120 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2121 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
2122 unsigned char *buf,
2123 size_t *olen )
2124 {
2125 unsigned char *p = buf;
2126
2127 if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE )
2128 {
2129 *olen = 0;
2130 return;
2131 }
2132
2133 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
2134
2135 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH, p, 0 );
2136 p += 2;
2137
2138 *p++ = 0x00;
2139 *p++ = 1;
2140
2141 *p++ = ssl->session_negotiate->mfl_code;
2142
2143 *olen = 5;
2144 }
2145 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2146
2147 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2148 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_supported_point_formats_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2149 static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
2150 unsigned char *buf,
2151 size_t *olen )
2152 {
2153 unsigned char *p = buf;
2154 ((void) ssl);
2155
2156 if( ( ssl->handshake->cli_exts &
2157 MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
2158 {
2159 *olen = 0;
2160 return;
2161 }
2162
2163 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
2164
2165 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS, p, 0 );
2166 p += 2;
2167
2168 *p++ = 0x00;
2169 *p++ = 2;
2170
2171 *p++ = 1;
2172 *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
2173
2174 *olen = 6;
2175 }
2176 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2177
2178 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2179 static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
2180 unsigned char *buf,
2181 size_t *olen )
2182 {
2183 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2184 unsigned char *p = buf;
2185 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2186 size_t kkpp_len;
2187
2188 *olen = 0;
2189
2190 /* Skip costly computation if not needed */
2191 if( ssl->handshake->ciphersuite_info->key_exchange !=
2192 MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2193 return;
2194
2195 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, ecjpake kkpp extension" ) );
2196
2197 if( end - p < 4 )
2198 {
2199 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2200 return;
2201 }
2202
2203 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ECJPAKE_KKPP, p, 0 );
2204 p += 2;
2205
2206 ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
2207 p + 2, end - p - 2, &kkpp_len,
2208 ssl->conf->f_rng, ssl->conf->p_rng );
2209 if( ret != 0 )
2210 {
2211 MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
2212 return;
2213 }
2214
2215 MBEDTLS_PUT_UINT16_BE( kkpp_len, p, 0 );
2216 p += 2;
2217
2218 *olen = kkpp_len + 4;
2219 }
2220 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2221
2222 #if defined(MBEDTLS_SSL_ALPN )
ssl_write_alpn_ext(mbedtls_ssl_context * ssl,unsigned char * buf,size_t * olen)2223 static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
2224 unsigned char *buf, size_t *olen )
2225 {
2226 if( ssl->alpn_chosen == NULL )
2227 {
2228 *olen = 0;
2229 return;
2230 }
2231
2232 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
2233
2234 /*
2235 * 0 . 1 ext identifier
2236 * 2 . 3 ext length
2237 * 4 . 5 protocol list length
2238 * 6 . 6 protocol name length
2239 * 7 . 7+n protocol name
2240 */
2241 MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ALPN, buf, 0);
2242
2243 *olen = 7 + strlen( ssl->alpn_chosen );
2244
2245 MBEDTLS_PUT_UINT16_BE( *olen - 4, buf, 2 );
2246
2247 MBEDTLS_PUT_UINT16_BE( *olen - 6, buf, 4 );
2248
2249 buf[6] = MBEDTLS_BYTE_0( *olen - 7 );
2250
2251 memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
2252 }
2253 #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
2254
2255 #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)2256 static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
2257 unsigned char *buf,
2258 size_t *olen )
2259 {
2260 size_t mki_len = 0, ext_len = 0;
2261 uint16_t profile_value = 0;
2262 const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2263
2264 *olen = 0;
2265
2266 if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ||
2267 ( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET ) )
2268 {
2269 return;
2270 }
2271
2272 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding use_srtp extension" ) );
2273
2274 if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED )
2275 {
2276 mki_len = ssl->dtls_srtp_info.mki_len;
2277 }
2278
2279 /* The extension total size is 9 bytes :
2280 * - 2 bytes for the extension tag
2281 * - 2 bytes for the total size
2282 * - 2 bytes for the protection profile length
2283 * - 2 bytes for the protection profile
2284 * - 1 byte for the mki length
2285 * + the actual mki length
2286 * Check we have enough room in the output buffer */
2287 if( (size_t)( end - buf ) < mki_len + 9 )
2288 {
2289 MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
2290 return;
2291 }
2292
2293 /* extension */
2294 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_USE_SRTP, buf, 0 );
2295 /*
2296 * total length 5 and mki value: only one profile(2 bytes)
2297 * and length(2 bytes) and srtp_mki )
2298 */
2299 ext_len = 5 + mki_len;
2300 MBEDTLS_PUT_UINT16_BE( ext_len, buf, 2 );
2301
2302 /* protection profile length: 2 */
2303 buf[4] = 0x00;
2304 buf[5] = 0x02;
2305 profile_value = mbedtls_ssl_check_srtp_profile_value(
2306 ssl->dtls_srtp_info.chosen_dtls_srtp_profile );
2307 if( profile_value != MBEDTLS_TLS_SRTP_UNSET )
2308 {
2309 MBEDTLS_PUT_UINT16_BE( profile_value, buf, 6 );
2310 }
2311 else
2312 {
2313 MBEDTLS_SSL_DEBUG_MSG( 1, ( "use_srtp extension invalid profile" ) );
2314 return;
2315 }
2316
2317 buf[8] = mki_len & 0xFF;
2318 memcpy( &buf[9], ssl->dtls_srtp_info.mki_value, mki_len );
2319
2320 *olen = 9 + mki_len;
2321 }
2322 #endif /* MBEDTLS_SSL_DTLS_SRTP */
2323
2324 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
ssl_write_hello_verify_request(mbedtls_ssl_context * ssl)2325 static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
2326 {
2327 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2328 unsigned char *p = ssl->out_msg + 4;
2329 unsigned char *cookie_len_byte;
2330
2331 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) );
2332
2333 /*
2334 * struct {
2335 * ProtocolVersion server_version;
2336 * opaque cookie<0..2^8-1>;
2337 * } HelloVerifyRequest;
2338 */
2339
2340 /* The RFC is not clear on this point, but sending the actual negotiated
2341 * version looks like the most interoperable thing to do. */
2342 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2343 ssl->conf->transport, p );
2344 MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 );
2345 p += 2;
2346
2347 /* If we get here, f_cookie_check is not null */
2348 if( ssl->conf->f_cookie_write == NULL )
2349 {
2350 MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) );
2351 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2352 }
2353
2354 /* Skip length byte until we know the length */
2355 cookie_len_byte = p++;
2356
2357 if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
2358 &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
2359 ssl->cli_id, ssl->cli_id_len ) ) != 0 )
2360 {
2361 MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
2362 return( ret );
2363 }
2364
2365 *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) );
2366
2367 MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte );
2368
2369 ssl->out_msglen = p - ssl->out_msg;
2370 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2371 ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
2372
2373 ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
2374
2375 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
2376 {
2377 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
2378 return( ret );
2379 }
2380
2381 #if defined(MBEDTLS_SSL_PROTO_DTLS)
2382 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2383 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
2384 {
2385 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
2386 return( ret );
2387 }
2388 #endif /* MBEDTLS_SSL_PROTO_DTLS */
2389
2390 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
2391
2392 return( 0 );
2393 }
2394 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2395
ssl_handle_id_based_session_resumption(mbedtls_ssl_context * ssl)2396 static void ssl_handle_id_based_session_resumption( mbedtls_ssl_context *ssl )
2397 {
2398 int ret;
2399 mbedtls_ssl_session session_tmp;
2400 mbedtls_ssl_session * const session = ssl->session_negotiate;
2401
2402 /* Resume is 0 by default, see ssl_handshake_init().
2403 * It may be already set to 1 by ssl_parse_session_ticket_ext(). */
2404 if( ssl->handshake->resume == 1 )
2405 return;
2406 if( session->id_len == 0 )
2407 return;
2408 if( ssl->conf->f_get_cache == NULL )
2409 return;
2410 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2411 if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
2412 return;
2413 #endif
2414
2415 mbedtls_ssl_session_init( &session_tmp );
2416
2417 ret = ssl->conf->f_get_cache( ssl->conf->p_cache,
2418 session->id,
2419 session->id_len,
2420 &session_tmp );
2421 if( ret != 0 )
2422 goto exit;
2423
2424 if( session->ciphersuite != session_tmp.ciphersuite ||
2425 session->compression != session_tmp.compression )
2426 {
2427 /* Mismatch between cached and negotiated session */
2428 goto exit;
2429 }
2430
2431 /* Move semantics */
2432 mbedtls_ssl_session_free( session );
2433 *session = session_tmp;
2434 memset( &session_tmp, 0, sizeof( session_tmp ) );
2435
2436 MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
2437 ssl->handshake->resume = 1;
2438
2439 exit:
2440
2441 mbedtls_ssl_session_free( &session_tmp );
2442 }
2443
ssl_write_server_hello(mbedtls_ssl_context * ssl)2444 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
2445 {
2446 #if defined(MBEDTLS_HAVE_TIME)
2447 mbedtls_time_t t;
2448 #endif
2449 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2450 size_t olen, ext_len = 0, n;
2451 unsigned char *buf, *p;
2452
2453 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
2454
2455 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
2456 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
2457 ssl->handshake->verify_cookie_len != 0 )
2458 {
2459 MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) );
2460 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2461
2462 return( ssl_write_hello_verify_request( ssl ) );
2463 }
2464 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
2465
2466 if( ssl->conf->f_rng == NULL )
2467 {
2468 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
2469 return( MBEDTLS_ERR_SSL_NO_RNG );
2470 }
2471
2472 /*
2473 * 0 . 0 handshake type
2474 * 1 . 3 handshake length
2475 * 4 . 5 protocol version
2476 * 6 . 9 UNIX time()
2477 * 10 . 37 random bytes
2478 */
2479 buf = ssl->out_msg;
2480 p = buf + 4;
2481
2482 mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
2483 ssl->conf->transport, p );
2484 p += 2;
2485
2486 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
2487 buf[4], buf[5] ) );
2488
2489 #if defined(MBEDTLS_HAVE_TIME)
2490 t = mbedtls_time( NULL );
2491 MBEDTLS_PUT_UINT32_BE( t, p, 0 );
2492 p += 4;
2493
2494 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
2495 (long long) t ) );
2496 #else
2497 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 )
2498 return( ret );
2499
2500 p += 4;
2501 #endif /* MBEDTLS_HAVE_TIME */
2502
2503 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 )
2504 return( ret );
2505
2506 p += 28;
2507
2508 memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
2509
2510 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
2511
2512 ssl_handle_id_based_session_resumption( ssl );
2513
2514 if( ssl->handshake->resume == 0 )
2515 {
2516 /*
2517 * New session, create a new session id,
2518 * unless we're about to issue a session ticket
2519 */
2520 ssl->state++;
2521
2522 #if defined(MBEDTLS_HAVE_TIME)
2523 ssl->session_negotiate->start = mbedtls_time( NULL );
2524 #endif
2525
2526 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2527 if( ssl->handshake->new_session_ticket != 0 )
2528 {
2529 ssl->session_negotiate->id_len = n = 0;
2530 memset( ssl->session_negotiate->id, 0, 32 );
2531 }
2532 else
2533 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
2534 {
2535 ssl->session_negotiate->id_len = n = 32;
2536 if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id,
2537 n ) ) != 0 )
2538 return( ret );
2539 }
2540 }
2541 else
2542 {
2543 /*
2544 * Resuming a session
2545 */
2546 n = ssl->session_negotiate->id_len;
2547 ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
2548
2549 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
2550 {
2551 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
2552 return( ret );
2553 }
2554 }
2555
2556 /*
2557 * 38 . 38 session id length
2558 * 39 . 38+n session id
2559 * 39+n . 40+n chosen ciphersuite
2560 * 41+n . 41+n chosen compression alg.
2561 * 42+n . 43+n extensions length
2562 * 44+n . 43+n+m extensions
2563 */
2564 *p++ = (unsigned char) ssl->session_negotiate->id_len;
2565 memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
2566 p += ssl->session_negotiate->id_len;
2567
2568 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n ) );
2569 MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
2570 MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
2571 ssl->handshake->resume ? "a" : "no" ) );
2572
2573 MBEDTLS_PUT_UINT16_BE( ssl->session_negotiate->ciphersuite, p, 0 );
2574 p += 2;
2575 *p++ = MBEDTLS_BYTE_0( ssl->session_negotiate->compression );
2576
2577 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s",
2578 mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
2579 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
2580 (unsigned int) ssl->session_negotiate->compression ) );
2581
2582 /*
2583 * First write extensions, then the total length
2584 */
2585 ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
2586 ext_len += olen;
2587
2588 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2589 ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
2590 ext_len += olen;
2591 #endif
2592
2593 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
2594 ssl_write_cid_ext( ssl, p + 2 + ext_len, &olen );
2595 ext_len += olen;
2596 #endif
2597
2598 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
2599 ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
2600 ext_len += olen;
2601 #endif
2602
2603 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2604 ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
2605 ext_len += olen;
2606 #endif
2607
2608 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
2609 ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
2610 ext_len += olen;
2611 #endif
2612
2613 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
2614 defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2615 if ( mbedtls_ssl_ciphersuite_uses_ec(
2616 mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
2617 {
2618 ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
2619 ext_len += olen;
2620 }
2621 #endif
2622
2623 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2624 ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
2625 ext_len += olen;
2626 #endif
2627
2628 #if defined(MBEDTLS_SSL_ALPN)
2629 ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
2630 ext_len += olen;
2631 #endif
2632
2633 #if defined(MBEDTLS_SSL_DTLS_SRTP)
2634 ssl_write_use_srtp_ext( ssl, p + 2 + ext_len, &olen );
2635 ext_len += olen;
2636 #endif
2637
2638 MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %" MBEDTLS_PRINTF_SIZET,
2639 ext_len ) );
2640
2641 if( ext_len > 0 )
2642 {
2643 MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
2644 p += 2 + ext_len;
2645 }
2646
2647 ssl->out_msglen = p - buf;
2648 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2649 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
2650
2651 ret = mbedtls_ssl_write_handshake_msg( ssl );
2652
2653 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
2654
2655 return( ret );
2656 }
2657
2658 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_write_certificate_request(mbedtls_ssl_context * ssl)2659 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
2660 {
2661 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
2662 ssl->handshake->ciphersuite_info;
2663
2664 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
2665
2666 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
2667 {
2668 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
2669 ssl->state++;
2670 return( 0 );
2671 }
2672
2673 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
2674 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
2675 }
2676 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_write_certificate_request(mbedtls_ssl_context * ssl)2677 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
2678 {
2679 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
2680 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
2681 ssl->handshake->ciphersuite_info;
2682 uint16_t dn_size, total_dn_size; /* excluding length bytes */
2683 size_t ct_len, sa_len; /* including length bytes */
2684 unsigned char *buf, *p;
2685 const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
2686 const mbedtls_x509_crt *crt;
2687 int authmode;
2688
2689 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
2690
2691 ssl->state++;
2692
2693 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
2694 if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
2695 authmode = ssl->handshake->sni_authmode;
2696 else
2697 #endif
2698 authmode = ssl->conf->authmode;
2699
2700 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ||
2701 authmode == MBEDTLS_SSL_VERIFY_NONE )
2702 {
2703 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
2704 return( 0 );
2705 }
2706
2707 /*
2708 * 0 . 0 handshake type
2709 * 1 . 3 handshake length
2710 * 4 . 4 cert type count
2711 * 5 .. m-1 cert types
2712 * m .. m+1 sig alg length (TLS 1.2 only)
2713 * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
2714 * n .. n+1 length of all DNs
2715 * n+2 .. n+3 length of DN 1
2716 * n+4 .. ... Distinguished Name #1
2717 * ... .. ... length of DN 2, etc.
2718 */
2719 buf = ssl->out_msg;
2720 p = buf + 4;
2721
2722 /*
2723 * Supported certificate types
2724 *
2725 * ClientCertificateType certificate_types<1..2^8-1>;
2726 * enum { (255) } ClientCertificateType;
2727 */
2728 ct_len = 0;
2729
2730 #if defined(MBEDTLS_RSA_C)
2731 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
2732 #endif
2733 #if defined(MBEDTLS_ECDSA_C)
2734 p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
2735 #endif
2736
2737 p[0] = (unsigned char) ct_len++;
2738 p += ct_len;
2739
2740 sa_len = 0;
2741 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
2742 /*
2743 * Add signature_algorithms for verify (TLS 1.2)
2744 *
2745 * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
2746 *
2747 * struct {
2748 * HashAlgorithm hash;
2749 * SignatureAlgorithm signature;
2750 * } SignatureAndHashAlgorithm;
2751 *
2752 * enum { (255) } HashAlgorithm;
2753 * enum { (255) } SignatureAlgorithm;
2754 */
2755 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
2756 {
2757 const int *cur;
2758
2759 /*
2760 * Supported signature algorithms
2761 */
2762 for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ )
2763 {
2764 unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur );
2765
2766 if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) )
2767 continue;
2768
2769 #if defined(MBEDTLS_RSA_C)
2770 p[2 + sa_len++] = hash;
2771 p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA;
2772 #endif
2773 #if defined(MBEDTLS_ECDSA_C)
2774 p[2 + sa_len++] = hash;
2775 p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA;
2776 #endif
2777 }
2778
2779 MBEDTLS_PUT_UINT16_BE( sa_len, p, 0 );
2780 sa_len += 2;
2781 p += sa_len;
2782 }
2783 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
2784
2785 /*
2786 * DistinguishedName certificate_authorities<0..2^16-1>;
2787 * opaque DistinguishedName<1..2^16-1>;
2788 */
2789 p += 2;
2790
2791 total_dn_size = 0;
2792
2793 if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED )
2794 {
2795 /* NOTE: If trusted certificates are provisioned
2796 * via a CA callback (configured through
2797 * `mbedtls_ssl_conf_ca_cb()`, then the
2798 * CertificateRequest is currently left empty. */
2799
2800 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
2801 if( ssl->handshake->sni_ca_chain != NULL )
2802 crt = ssl->handshake->sni_ca_chain;
2803 else
2804 #endif
2805 crt = ssl->conf->ca_chain;
2806
2807 while( crt != NULL && crt->version != 0 )
2808 {
2809 /* It follows from RFC 5280 A.1 that this length
2810 * can be represented in at most 11 bits. */
2811 dn_size = (uint16_t) crt->subject_raw.len;
2812
2813 if( end < p || (size_t)( end - p ) < 2 + (size_t) dn_size )
2814 {
2815 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) );
2816 break;
2817 }
2818
2819 MBEDTLS_PUT_UINT16_BE( dn_size, p, 0 );
2820 p += 2;
2821 memcpy( p, crt->subject_raw.p, dn_size );
2822 p += dn_size;
2823
2824 MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size );
2825
2826 total_dn_size += 2 + dn_size;
2827 crt = crt->next;
2828 }
2829 }
2830
2831 ssl->out_msglen = p - buf;
2832 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
2833 ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
2834 MBEDTLS_PUT_UINT16_BE( total_dn_size, ssl->out_msg, 4 + ct_len + sa_len );
2835
2836 ret = mbedtls_ssl_write_handshake_msg( ssl );
2837
2838 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
2839
2840 return( ret );
2841 }
2842 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
2843
2844 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
2845 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
ssl_get_ecdh_params_from_cert(mbedtls_ssl_context * ssl)2846 static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
2847 {
2848 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2849
2850 if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) )
2851 {
2852 MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
2853 return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
2854 }
2855
2856 if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx,
2857 mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ),
2858 MBEDTLS_ECDH_OURS ) ) != 0 )
2859 {
2860 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret );
2861 return( ret );
2862 }
2863
2864 return( 0 );
2865 }
2866 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
2867 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
2868
2869 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
2870 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
ssl_resume_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)2871 static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
2872 size_t *signature_len )
2873 {
2874 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
2875 * signature length which will be added in ssl_write_server_key_exchange
2876 * after the call to ssl_prepare_server_key_exchange.
2877 * ssl_write_server_key_exchange also takes care of incrementing
2878 * ssl->out_msglen. */
2879 unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
2880 size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
2881 - sig_start );
2882 int ret = ssl->conf->f_async_resume( ssl,
2883 sig_start, signature_len, sig_max_len );
2884 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
2885 {
2886 ssl->handshake->async_in_progress = 0;
2887 mbedtls_ssl_set_async_operation_data( ssl, NULL );
2888 }
2889 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
2890 return( ret );
2891 }
2892 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
2893 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
2894
2895 /* Prepare the ServerKeyExchange message, up to and including
2896 * calculating the signature if any, but excluding formatting the
2897 * signature and sending the message. */
ssl_prepare_server_key_exchange(mbedtls_ssl_context * ssl,size_t * signature_len)2898 static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
2899 size_t *signature_len )
2900 {
2901 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
2902 ssl->handshake->ciphersuite_info;
2903
2904 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED)
2905 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
2906 unsigned char *dig_signed = NULL;
2907 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
2908 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */
2909
2910 (void) ciphersuite_info; /* unused in some configurations */
2911 #if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
2912 (void) signature_len;
2913 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
2914
2915 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
2916 #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
2917 size_t out_buf_len = ssl->out_buf_len - ( ssl->out_msg - ssl->out_buf );
2918 #else
2919 size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN - ( ssl->out_msg - ssl->out_buf );
2920 #endif
2921 #endif
2922
2923 ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
2924
2925 /*
2926 *
2927 * Part 1: Provide key exchange parameters for chosen ciphersuite.
2928 *
2929 */
2930
2931 /*
2932 * - ECJPAKE key exchanges
2933 */
2934 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
2935 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
2936 {
2937 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2938 size_t len = 0;
2939
2940 ret = mbedtls_ecjpake_write_round_two(
2941 &ssl->handshake->ecjpake_ctx,
2942 ssl->out_msg + ssl->out_msglen,
2943 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
2944 ssl->conf->f_rng, ssl->conf->p_rng );
2945 if( ret != 0 )
2946 {
2947 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret );
2948 return( ret );
2949 }
2950
2951 ssl->out_msglen += len;
2952 }
2953 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
2954
2955 /*
2956 * For (EC)DHE key exchanges with PSK, parameters are prefixed by support
2957 * identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
2958 * we use empty support identity hints here.
2959 **/
2960 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
2961 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
2962 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
2963 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
2964 {
2965 ssl->out_msg[ssl->out_msglen++] = 0x00;
2966 ssl->out_msg[ssl->out_msglen++] = 0x00;
2967 }
2968 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
2969 MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
2970
2971 /*
2972 * - DHE key exchanges
2973 */
2974 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED)
2975 if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
2976 {
2977 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
2978 size_t len = 0;
2979
2980 if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
2981 {
2982 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) );
2983 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
2984 }
2985
2986 /*
2987 * Ephemeral DH parameters:
2988 *
2989 * struct {
2990 * opaque dh_p<1..2^16-1>;
2991 * opaque dh_g<1..2^16-1>;
2992 * opaque dh_Ys<1..2^16-1>;
2993 * } ServerDHParams;
2994 */
2995 if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx,
2996 &ssl->conf->dhm_P,
2997 &ssl->conf->dhm_G ) ) != 0 )
2998 {
2999 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret );
3000 return( ret );
3001 }
3002
3003 if( ( ret = mbedtls_dhm_make_params(
3004 &ssl->handshake->dhm_ctx,
3005 (int) mbedtls_dhm_get_len( &ssl->handshake->dhm_ctx ),
3006 ssl->out_msg + ssl->out_msglen, &len,
3007 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3008 {
3009 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret );
3010 return( ret );
3011 }
3012
3013 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3014 dig_signed = ssl->out_msg + ssl->out_msglen;
3015 #endif
3016
3017 ssl->out_msglen += len;
3018
3019 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
3020 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
3021 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
3022 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
3023 }
3024 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */
3025
3026 /*
3027 * - ECDHE key exchanges
3028 */
3029 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED)
3030 if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) )
3031 {
3032 /*
3033 * Ephemeral ECDH parameters:
3034 *
3035 * struct {
3036 * ECParameters curve_params;
3037 * ECPoint public;
3038 * } ServerECDHParams;
3039 */
3040 const mbedtls_ecp_curve_info **curve = NULL;
3041 const uint16_t *group_list = mbedtls_ssl_get_groups( ssl );
3042 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3043 size_t len = 0;
3044
3045 /* Match our preference list against the offered curves */
3046 if( group_list == NULL )
3047 return( MBEDTLS_ERR_SSL_BAD_CONFIG );
3048 for( ; *group_list != 0; group_list++ )
3049 for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
3050 if( (*curve)->tls_id == *group_list )
3051 goto curve_matching_done;
3052
3053 curve_matching_done:
3054 if( curve == NULL || *curve == NULL )
3055 {
3056 MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
3057 return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
3058 }
3059
3060 MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
3061
3062 if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
3063 (*curve)->grp_id ) ) != 0 )
3064 {
3065 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
3066 return( ret );
3067 }
3068
3069 if( ( ret = mbedtls_ecdh_make_params(
3070 &ssl->handshake->ecdh_ctx, &len,
3071 ssl->out_msg + ssl->out_msglen,
3072 MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
3073 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3074 {
3075 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
3076 return( ret );
3077 }
3078
3079 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3080 dig_signed = ssl->out_msg + ssl->out_msglen;
3081 #endif
3082
3083 ssl->out_msglen += len;
3084
3085 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3086 MBEDTLS_DEBUG_ECDH_Q );
3087 }
3088 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */
3089
3090 /*
3091 *
3092 * Part 2: For key exchanges involving the server signing the
3093 * exchange parameters, compute and add the signature here.
3094 *
3095 */
3096 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3097 if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
3098 {
3099 size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
3100 size_t hashlen = 0;
3101 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3102 unsigned char hash[PSA_HASH_MAX_SIZE];
3103 #else
3104 unsigned char hash[MBEDTLS_MD_MAX_SIZE];
3105 #endif
3106 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3107
3108 /*
3109 * 2.1: Choose hash algorithm:
3110 * For TLS 1.2, obey signature-hash-algorithm extension
3111 * to choose appropriate hash.
3112 */
3113
3114 mbedtls_md_type_t md_alg;
3115
3116 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3117 mbedtls_pk_type_t sig_alg =
3118 mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
3119 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3120 {
3121 /* For TLS 1.2, obey signature-hash-algorithm extension
3122 * (RFC 5246, Sec. 7.4.1.4.1). */
3123 if( sig_alg == MBEDTLS_PK_NONE ||
3124 ( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
3125 sig_alg ) ) == MBEDTLS_MD_NONE )
3126 {
3127 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3128 /* (... because we choose a cipher suite
3129 * only if there is a matching hash.) */
3130 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3131 }
3132 }
3133 else
3134 {
3135 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3136 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3137 }
3138 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3139
3140 MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %u for signing", (unsigned) md_alg ) );
3141
3142 /*
3143 * 2.2: Compute the hash to be signed
3144 */
3145 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3146 if( md_alg != MBEDTLS_MD_NONE )
3147 {
3148 ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
3149 dig_signed,
3150 dig_signed_len,
3151 md_alg );
3152 if( ret != 0 )
3153 return( ret );
3154 }
3155 else
3156 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3157 {
3158 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3159 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3160 }
3161
3162 MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
3163
3164 /*
3165 * 2.3: Compute and add the signature
3166 */
3167 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3168 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
3169 {
3170 /*
3171 * For TLS 1.2, we need to specify signature and hash algorithm
3172 * explicitly through a prefix to the signature.
3173 *
3174 * struct {
3175 * HashAlgorithm hash;
3176 * SignatureAlgorithm signature;
3177 * } SignatureAndHashAlgorithm;
3178 *
3179 * struct {
3180 * SignatureAndHashAlgorithm algorithm;
3181 * opaque signature<0..2^16-1>;
3182 * } DigitallySigned;
3183 *
3184 */
3185
3186 ssl->out_msg[ssl->out_msglen++] =
3187 mbedtls_ssl_hash_from_md_alg( md_alg );
3188 ssl->out_msg[ssl->out_msglen++] =
3189 mbedtls_ssl_sig_from_pk_alg( sig_alg );
3190 }
3191 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
3192
3193 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3194 if( ssl->conf->f_async_sign_start != NULL )
3195 {
3196 ret = ssl->conf->f_async_sign_start( ssl,
3197 mbedtls_ssl_own_cert( ssl ),
3198 md_alg, hash, hashlen );
3199 switch( ret )
3200 {
3201 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3202 /* act as if f_async_sign was null */
3203 break;
3204 case 0:
3205 ssl->handshake->async_in_progress = 1;
3206 return( ssl_resume_server_key_exchange( ssl, signature_len ) );
3207 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3208 ssl->handshake->async_in_progress = 1;
3209 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3210 default:
3211 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret );
3212 return( ret );
3213 }
3214 }
3215 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3216
3217 if( mbedtls_ssl_own_key( ssl ) == NULL )
3218 {
3219 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) );
3220 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3221 }
3222
3223 /* Append the signature to ssl->out_msg, leaving 2 bytes for the
3224 * signature length which will be added in ssl_write_server_key_exchange
3225 * after the call to ssl_prepare_server_key_exchange.
3226 * ssl_write_server_key_exchange also takes care of incrementing
3227 * ssl->out_msglen. */
3228 if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ),
3229 md_alg, hash, hashlen,
3230 ssl->out_msg + ssl->out_msglen + 2,
3231 out_buf_len - ssl->out_msglen - 2,
3232 signature_len,
3233 ssl->conf->f_rng,
3234 ssl->conf->p_rng ) ) != 0 )
3235 {
3236 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret );
3237 return( ret );
3238 }
3239 }
3240 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3241
3242 return( 0 );
3243 }
3244
3245 /* Prepare the ServerKeyExchange message and send it. For ciphersuites
3246 * that do not include a ServerKeyExchange message, do nothing. Either
3247 * way, if successful, move on to the next step in the SSL state
3248 * machine. */
ssl_write_server_key_exchange(mbedtls_ssl_context * ssl)3249 static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
3250 {
3251 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3252 size_t signature_len = 0;
3253 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3254 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3255 ssl->handshake->ciphersuite_info;
3256 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3257
3258 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
3259
3260 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
3261 /* Extract static ECDH parameters and abort if ServerKeyExchange
3262 * is not needed. */
3263 if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) )
3264 {
3265 /* For suites involving ECDH, extract DH parameters
3266 * from certificate at this point. */
3267 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED)
3268 if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) )
3269 {
3270 ssl_get_ecdh_params_from_cert( ssl );
3271 }
3272 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */
3273
3274 /* Key exchanges not involving ephemeral keys don't use
3275 * ServerKeyExchange, so end here. */
3276 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
3277 ssl->state++;
3278 return( 0 );
3279 }
3280 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
3281
3282 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
3283 defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3284 /* If we have already prepared the message and there is an ongoing
3285 * signature operation, resume signing. */
3286 if( ssl->handshake->async_in_progress != 0 )
3287 {
3288 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) );
3289 ret = ssl_resume_server_key_exchange( ssl, &signature_len );
3290 }
3291 else
3292 #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
3293 defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
3294 {
3295 /* ServerKeyExchange is needed. Prepare the message. */
3296 ret = ssl_prepare_server_key_exchange( ssl, &signature_len );
3297 }
3298
3299 if( ret != 0 )
3300 {
3301 /* If we're starting to write a new message, set ssl->out_msglen
3302 * to 0. But if we're resuming after an asynchronous message,
3303 * out_msglen is the amount of data written so far and mst be
3304 * preserved. */
3305 if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3306 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) );
3307 else
3308 ssl->out_msglen = 0;
3309 return( ret );
3310 }
3311
3312 /* If there is a signature, write its length.
3313 * ssl_prepare_server_key_exchange already wrote the signature
3314 * itself at its proper place in the output buffer. */
3315 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
3316 if( signature_len != 0 )
3317 {
3318 ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_1( signature_len );
3319 ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_0( signature_len );
3320
3321 MBEDTLS_SSL_DEBUG_BUF( 3, "my signature",
3322 ssl->out_msg + ssl->out_msglen,
3323 signature_len );
3324
3325 /* Skip over the already-written signature */
3326 ssl->out_msglen += signature_len;
3327 }
3328 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
3329
3330 /* Add header and send. */
3331 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3332 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
3333
3334 ssl->state++;
3335
3336 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3337 {
3338 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3339 return( ret );
3340 }
3341
3342 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
3343 return( 0 );
3344 }
3345
ssl_write_server_hello_done(mbedtls_ssl_context * ssl)3346 static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
3347 {
3348 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3349
3350 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
3351
3352 ssl->out_msglen = 4;
3353 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
3354 ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
3355
3356 ssl->state++;
3357
3358 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3359 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
3360 mbedtls_ssl_send_flight_completed( ssl );
3361 #endif
3362
3363 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
3364 {
3365 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
3366 return( ret );
3367 }
3368
3369 #if defined(MBEDTLS_SSL_PROTO_DTLS)
3370 if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
3371 ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
3372 {
3373 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
3374 return( ret );
3375 }
3376 #endif /* MBEDTLS_SSL_PROTO_DTLS */
3377
3378 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
3379
3380 return( 0 );
3381 }
3382
3383 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
3384 defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
ssl_parse_client_dh_public(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3385 static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p,
3386 const unsigned char *end )
3387 {
3388 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
3389 size_t n;
3390
3391 /*
3392 * Receive G^Y mod P, premaster = (G^Y)^X mod P
3393 */
3394 if( *p + 2 > end )
3395 {
3396 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3397 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3398 }
3399
3400 n = ( (*p)[0] << 8 ) | (*p)[1];
3401 *p += 2;
3402
3403 if( *p + n > end )
3404 {
3405 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3406 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3407 }
3408
3409 if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 )
3410 {
3411 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret );
3412 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3413 }
3414
3415 *p += n;
3416
3417 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
3418
3419 return( ret );
3420 }
3421 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
3422 MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3423
3424 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3425 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3426
3427 #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)3428 static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl,
3429 unsigned char *peer_pms,
3430 size_t *peer_pmslen,
3431 size_t peer_pmssize )
3432 {
3433 int ret = ssl->conf->f_async_resume( ssl,
3434 peer_pms, peer_pmslen, peer_pmssize );
3435 if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3436 {
3437 ssl->handshake->async_in_progress = 0;
3438 mbedtls_ssl_set_async_operation_data( ssl, NULL );
3439 }
3440 MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret );
3441 return( ret );
3442 }
3443 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3444
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)3445 static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl,
3446 const unsigned char *p,
3447 const unsigned char *end,
3448 unsigned char *peer_pms,
3449 size_t *peer_pmslen,
3450 size_t peer_pmssize )
3451 {
3452 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3453 mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl );
3454 mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk;
3455 size_t len = mbedtls_pk_get_len( public_key );
3456
3457 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3458 /* If we have already started decoding the message and there is an ongoing
3459 * decryption operation, resume signing. */
3460 if( ssl->handshake->async_in_progress != 0 )
3461 {
3462 MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) );
3463 return( ssl_resume_decrypt_pms( ssl,
3464 peer_pms, peer_pmslen, peer_pmssize ) );
3465 }
3466 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3467
3468 /*
3469 * Prepare to decrypt the premaster using own private RSA key
3470 */
3471 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
3472 if ( p + 2 > end ) {
3473 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3474 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3475 }
3476 if( *p++ != MBEDTLS_BYTE_1( len ) ||
3477 *p++ != MBEDTLS_BYTE_0( len ) )
3478 {
3479 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3480 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3481 }
3482 #endif
3483
3484 if( p + len != end )
3485 {
3486 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3487 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3488 }
3489
3490 /*
3491 * Decrypt the premaster secret
3492 */
3493 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3494 if( ssl->conf->f_async_decrypt_start != NULL )
3495 {
3496 ret = ssl->conf->f_async_decrypt_start( ssl,
3497 mbedtls_ssl_own_cert( ssl ),
3498 p, len );
3499 switch( ret )
3500 {
3501 case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
3502 /* act as if f_async_decrypt_start was null */
3503 break;
3504 case 0:
3505 ssl->handshake->async_in_progress = 1;
3506 return( ssl_resume_decrypt_pms( ssl,
3507 peer_pms,
3508 peer_pmslen,
3509 peer_pmssize ) );
3510 case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
3511 ssl->handshake->async_in_progress = 1;
3512 return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
3513 default:
3514 MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret );
3515 return( ret );
3516 }
3517 }
3518 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3519
3520 if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) )
3521 {
3522 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
3523 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3524 }
3525
3526 ret = mbedtls_pk_decrypt( private_key, p, len,
3527 peer_pms, peer_pmslen, peer_pmssize,
3528 ssl->conf->f_rng, ssl->conf->p_rng );
3529 return( ret );
3530 }
3531
ssl_parse_encrypted_pms(mbedtls_ssl_context * ssl,const unsigned char * p,const unsigned char * end,size_t pms_offset)3532 static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
3533 const unsigned char *p,
3534 const unsigned char *end,
3535 size_t pms_offset )
3536 {
3537 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3538 unsigned char *pms = ssl->handshake->premaster + pms_offset;
3539 unsigned char ver[2];
3540 unsigned char fake_pms[48], peer_pms[48];
3541 unsigned char mask;
3542 size_t i, peer_pmslen;
3543 unsigned int diff;
3544
3545 /* In case of a failure in decryption, the decryption may write less than
3546 * 2 bytes of output, but we always read the first two bytes. It doesn't
3547 * matter in the end because diff will be nonzero in that case due to
3548 * ret being nonzero, and we only care whether diff is 0.
3549 * But do initialize peer_pms and peer_pmslen for robustness anyway. This
3550 * also makes memory analyzers happy (don't access uninitialized memory,
3551 * even if it's an unsigned char). */
3552 peer_pms[0] = peer_pms[1] = ~0;
3553 peer_pmslen = 0;
3554
3555 ret = ssl_decrypt_encrypted_pms( ssl, p, end,
3556 peer_pms,
3557 &peer_pmslen,
3558 sizeof( peer_pms ) );
3559
3560 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3561 if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
3562 return( ret );
3563 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3564
3565 mbedtls_ssl_write_version( ssl->handshake->max_major_ver,
3566 ssl->handshake->max_minor_ver,
3567 ssl->conf->transport, ver );
3568
3569 /* Avoid data-dependent branches while checking for invalid
3570 * padding, to protect against timing-based Bleichenbacher-type
3571 * attacks. */
3572 diff = (unsigned int) ret;
3573 diff |= peer_pmslen ^ 48;
3574 diff |= peer_pms[0] ^ ver[0];
3575 diff |= peer_pms[1] ^ ver[1];
3576
3577 /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
3578 mask = mbedtls_ct_uint_mask( diff );
3579
3580 /*
3581 * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
3582 * must not cause the connection to end immediately; instead, send a
3583 * bad_record_mac later in the handshake.
3584 * To protect against timing-based variants of the attack, we must
3585 * not have any branch that depends on whether the decryption was
3586 * successful. In particular, always generate the fake premaster secret,
3587 * regardless of whether it will ultimately influence the output or not.
3588 */
3589 ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) );
3590 if( ret != 0 )
3591 {
3592 /* It's ok to abort on an RNG failure, since this does not reveal
3593 * anything about the RSA decryption. */
3594 return( ret );
3595 }
3596
3597 #if defined(MBEDTLS_SSL_DEBUG_ALL)
3598 if( diff != 0 )
3599 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3600 #endif
3601
3602 if( sizeof( ssl->handshake->premaster ) < pms_offset ||
3603 sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
3604 {
3605 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3606 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3607 }
3608 ssl->handshake->pmslen = 48;
3609
3610 /* Set pms to either the true or the fake PMS, without
3611 * data-dependent branches. */
3612 for( i = 0; i < ssl->handshake->pmslen; i++ )
3613 pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
3614
3615 return( 0 );
3616 }
3617 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
3618 MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
3619
3620 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
ssl_parse_client_psk_identity(mbedtls_ssl_context * ssl,unsigned char ** p,const unsigned char * end)3621 static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p,
3622 const unsigned char *end )
3623 {
3624 int ret = 0;
3625 uint16_t n;
3626
3627 if( ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
3628 {
3629 MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
3630 return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
3631 }
3632
3633 /*
3634 * Receive client pre-shared key identity name
3635 */
3636 if( end - *p < 2 )
3637 {
3638 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3639 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3640 }
3641
3642 n = ( (*p)[0] << 8 ) | (*p)[1];
3643 *p += 2;
3644
3645 if( n == 0 || n > end - *p )
3646 {
3647 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3648 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3649 }
3650
3651 if( ssl->conf->f_psk != NULL )
3652 {
3653 if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 )
3654 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
3655 }
3656 else
3657 {
3658 /* Identity is not a big secret since clients send it in the clear,
3659 * but treat it carefully anyway, just in case */
3660 if( n != ssl->conf->psk_identity_len ||
3661 mbedtls_ct_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
3662 {
3663 ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
3664 }
3665 }
3666
3667 if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
3668 {
3669 MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
3670 mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
3671 MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
3672 return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
3673 }
3674
3675 *p += n;
3676
3677 return( 0 );
3678 }
3679 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
3680
ssl_parse_client_key_exchange(mbedtls_ssl_context * ssl)3681 static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
3682 {
3683 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
3684 const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
3685 unsigned char *p, *end;
3686
3687 ciphersuite_info = ssl->handshake->ciphersuite_info;
3688
3689 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
3690
3691 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
3692 ( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
3693 defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
3694 if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
3695 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) &&
3696 ( ssl->handshake->async_in_progress != 0 ) )
3697 {
3698 /* We've already read a record and there is an asynchronous
3699 * operation in progress to decrypt it. So skip reading the
3700 * record. */
3701 MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) );
3702 }
3703 else
3704 #endif
3705 if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
3706 {
3707 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
3708 return( ret );
3709 }
3710
3711 p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
3712 end = ssl->in_msg + ssl->in_hslen;
3713
3714 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
3715 {
3716 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3717 return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
3718 }
3719
3720 if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
3721 {
3722 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
3723 return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
3724 }
3725
3726 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
3727 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
3728 {
3729 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
3730 {
3731 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
3732 return( ret );
3733 }
3734
3735 if( p != end )
3736 {
3737 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
3738 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3739 }
3740
3741 if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
3742 ssl->handshake->premaster,
3743 MBEDTLS_PREMASTER_SIZE,
3744 &ssl->handshake->pmslen,
3745 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3746 {
3747 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
3748 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3749 }
3750
3751 MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
3752 }
3753 else
3754 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
3755 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
3756 defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
3757 defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
3758 defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
3759 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
3760 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
3761 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
3762 ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
3763 {
3764 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
3765 p, end - p) ) != 0 )
3766 {
3767 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
3768 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3769 }
3770
3771 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3772 MBEDTLS_DEBUG_ECDH_QP );
3773
3774 if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
3775 &ssl->handshake->pmslen,
3776 ssl->handshake->premaster,
3777 MBEDTLS_MPI_MAX_SIZE,
3778 ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
3779 {
3780 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
3781 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3782 }
3783
3784 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3785 MBEDTLS_DEBUG_ECDH_Z );
3786 }
3787 else
3788 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
3789 MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
3790 MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
3791 MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
3792 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
3793 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
3794 {
3795 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3796 {
3797 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3798 return( ret );
3799 }
3800
3801 if( p != end )
3802 {
3803 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
3804 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3805 }
3806
3807 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3808 /* For opaque PSKs, we perform the PSK-to-MS derivation atomatically
3809 * and skip the intermediate PMS. */
3810 if( ssl_use_opaque_psk( ssl ) == 1 )
3811 MBEDTLS_SSL_DEBUG_MSG( 1, ( "skip PMS generation for opaque PSK" ) );
3812 else
3813 #endif /* MBEDTLS_USE_PSA_CRYPTO */
3814 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3815 ciphersuite_info->key_exchange ) ) != 0 )
3816 {
3817 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3818 return( ret );
3819 }
3820 }
3821 else
3822 #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
3823 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
3824 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
3825 {
3826 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
3827 if ( ssl->handshake->async_in_progress != 0 )
3828 {
3829 /* There is an asynchronous operation in progress to
3830 * decrypt the encrypted premaster secret, so skip
3831 * directly to resuming this operation. */
3832 MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) );
3833 /* Update p to skip the PSK identity. ssl_parse_encrypted_pms
3834 * won't actually use it, but maintain p anyway for robustness. */
3835 p += ssl->conf->psk_identity_len + 2;
3836 }
3837 else
3838 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
3839 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3840 {
3841 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3842 return( ret );
3843 }
3844
3845 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3846 /* Opaque PSKs are currently only supported for PSK-only. */
3847 if( ssl_use_opaque_psk( ssl ) == 1 )
3848 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
3849 #endif
3850
3851 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
3852 {
3853 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
3854 return( ret );
3855 }
3856
3857 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3858 ciphersuite_info->key_exchange ) ) != 0 )
3859 {
3860 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3861 return( ret );
3862 }
3863 }
3864 else
3865 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
3866 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
3867 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
3868 {
3869 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3870 {
3871 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3872 return( ret );
3873 }
3874 if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
3875 {
3876 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
3877 return( ret );
3878 }
3879
3880 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3881 /* Opaque PSKs are currently only supported for PSK-only. */
3882 if( ssl_use_opaque_psk( ssl ) == 1 )
3883 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
3884 #endif
3885
3886 if( p != end )
3887 {
3888 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
3889 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3890 }
3891
3892 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3893 ciphersuite_info->key_exchange ) ) != 0 )
3894 {
3895 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3896 return( ret );
3897 }
3898 }
3899 else
3900 #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
3901 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
3902 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
3903 {
3904 if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
3905 {
3906 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
3907 return( ret );
3908 }
3909
3910 if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
3911 p, end - p ) ) != 0 )
3912 {
3913 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
3914 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
3915 }
3916
3917 #if defined(MBEDTLS_USE_PSA_CRYPTO)
3918 /* Opaque PSKs are currently only supported for PSK-only. */
3919 if( ssl_use_opaque_psk( ssl ) == 1 )
3920 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
3921 #endif
3922
3923 MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
3924 MBEDTLS_DEBUG_ECDH_QP );
3925
3926 if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
3927 ciphersuite_info->key_exchange ) ) != 0 )
3928 {
3929 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
3930 return( ret );
3931 }
3932 }
3933 else
3934 #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
3935 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
3936 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
3937 {
3938 if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 )
3939 {
3940 MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
3941 return( ret );
3942 }
3943 }
3944 else
3945 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
3946 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
3947 if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
3948 {
3949 ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx,
3950 p, end - p );
3951 if( ret != 0 )
3952 {
3953 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
3954 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3955 }
3956
3957 ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
3958 ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
3959 ssl->conf->f_rng, ssl->conf->p_rng );
3960 if( ret != 0 )
3961 {
3962 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
3963 return( ret );
3964 }
3965 }
3966 else
3967 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
3968 {
3969 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
3970 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
3971 }
3972
3973 if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
3974 {
3975 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
3976 return( ret );
3977 }
3978
3979 ssl->state++;
3980
3981 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
3982
3983 return( 0 );
3984 }
3985
3986 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)3987 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
3988 {
3989 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
3990 ssl->handshake->ciphersuite_info;
3991
3992 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
3993
3994 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
3995 {
3996 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
3997 ssl->state++;
3998 return( 0 );
3999 }
4000
4001 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4002 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4003 }
4004 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
ssl_parse_certificate_verify(mbedtls_ssl_context * ssl)4005 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
4006 {
4007 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
4008 size_t i, sig_len;
4009 unsigned char hash[48];
4010 unsigned char *hash_start = hash;
4011 size_t hashlen;
4012 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4013 mbedtls_pk_type_t pk_alg;
4014 #endif
4015 mbedtls_md_type_t md_alg;
4016 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
4017 ssl->handshake->ciphersuite_info;
4018 mbedtls_pk_context * peer_pk;
4019
4020 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
4021
4022 if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
4023 {
4024 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4025 ssl->state++;
4026 return( 0 );
4027 }
4028
4029 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4030 if( ssl->session_negotiate->peer_cert == NULL )
4031 {
4032 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4033 ssl->state++;
4034 return( 0 );
4035 }
4036 #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4037 if( ssl->session_negotiate->peer_cert_digest == NULL )
4038 {
4039 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
4040 ssl->state++;
4041 return( 0 );
4042 }
4043 #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4044
4045 /* Read the message without adding it to the checksum */
4046 ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
4047 if( 0 != ret )
4048 {
4049 MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
4050 return( ret );
4051 }
4052
4053 ssl->state++;
4054
4055 /* Process the message contents */
4056 if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
4057 ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY )
4058 {
4059 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4060 return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
4061 }
4062
4063 i = mbedtls_ssl_hs_hdr_len( ssl );
4064
4065 #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
4066 peer_pk = &ssl->handshake->peer_pubkey;
4067 #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4068 if( ssl->session_negotiate->peer_cert == NULL )
4069 {
4070 /* Should never happen */
4071 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4072 }
4073 peer_pk = &ssl->session_negotiate->peer_cert->pk;
4074 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
4075
4076 /*
4077 * struct {
4078 * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
4079 * opaque signature<0..2^16-1>;
4080 * } DigitallySigned;
4081 */
4082 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
4083 if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
4084 {
4085 if( i + 2 > ssl->in_hslen )
4086 {
4087 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4088 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
4089 }
4090
4091 /*
4092 * Hash
4093 */
4094 md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] );
4095
4096 if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) )
4097 {
4098 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4099 " for verify message" ) );
4100 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
4101 }
4102
4103 #if !defined(MBEDTLS_MD_SHA1)
4104 if( MBEDTLS_MD_SHA1 == md_alg )
4105 hash_start += 16;
4106 #endif
4107
4108 /* Info from md_alg will be used instead */
4109 hashlen = 0;
4110
4111 i++;
4112
4113 /*
4114 * Signature
4115 */
4116 if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) )
4117 == MBEDTLS_PK_NONE )
4118 {
4119 MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
4120 " for verify message" ) );
4121 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
4122 }
4123
4124 /*
4125 * Check the certificate's key type matches the signature alg
4126 */
4127 if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
4128 {
4129 MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
4130 return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
4131 }
4132
4133 i++;
4134 }
4135 else
4136 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
4137 {
4138 MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
4139 return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
4140 }
4141
4142 if( i + 2 > ssl->in_hslen )
4143 {
4144 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4145 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
4146 }
4147
4148 sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
4149 i += 2;
4150
4151 if( i + sig_len != ssl->in_hslen )
4152 {
4153 MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
4154 return( MBEDTLS_ERR_SSL_DECODE_ERROR );
4155 }
4156
4157 /* Calculate hash and verify signature */
4158 {
4159 size_t dummy_hlen;
4160 ssl->handshake->calc_verify( ssl, hash, &dummy_hlen );
4161 }
4162
4163 if( ( ret = mbedtls_pk_verify( peer_pk,
4164 md_alg, hash_start, hashlen,
4165 ssl->in_msg + i, sig_len ) ) != 0 )
4166 {
4167 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
4168 return( ret );
4169 }
4170
4171 mbedtls_ssl_update_handshake_status( ssl );
4172
4173 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
4174
4175 return( ret );
4176 }
4177 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
4178
4179 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_new_session_ticket(mbedtls_ssl_context * ssl)4180 static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
4181 {
4182 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
4183 size_t tlen;
4184 uint32_t lifetime;
4185
4186 MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
4187
4188 ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
4189 ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
4190
4191 /*
4192 * struct {
4193 * uint32 ticket_lifetime_hint;
4194 * opaque ticket<0..2^16-1>;
4195 * } NewSessionTicket;
4196 *
4197 * 4 . 7 ticket_lifetime_hint (0 = unspecified)
4198 * 8 . 9 ticket_len (n)
4199 * 10 . 9+n ticket content
4200 */
4201
4202 if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
4203 ssl->session_negotiate,
4204 ssl->out_msg + 10,
4205 ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
4206 &tlen, &lifetime ) ) != 0 )
4207 {
4208 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
4209 tlen = 0;
4210 }
4211
4212 MBEDTLS_PUT_UINT32_BE( lifetime, ssl->out_msg, 4 );
4213 MBEDTLS_PUT_UINT16_BE( tlen, ssl->out_msg, 8 );
4214 ssl->out_msglen = 10 + tlen;
4215
4216 /*
4217 * Morally equivalent to updating ssl->state, but NewSessionTicket and
4218 * ChangeCipherSpec share the same state.
4219 */
4220 ssl->handshake->new_session_ticket = 0;
4221
4222 if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
4223 {
4224 MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
4225 return( ret );
4226 }
4227
4228 MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
4229
4230 return( 0 );
4231 }
4232 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
4233
4234 /*
4235 * SSL handshake -- server side -- single step
4236 */
mbedtls_ssl_handshake_server_step(mbedtls_ssl_context * ssl)4237 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
4238 {
4239 int ret = 0;
4240
4241 MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
4242
4243 switch( ssl->state )
4244 {
4245 case MBEDTLS_SSL_HELLO_REQUEST:
4246 ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
4247 break;
4248
4249 /*
4250 * <== ClientHello
4251 */
4252 case MBEDTLS_SSL_CLIENT_HELLO:
4253 ret = ssl_parse_client_hello( ssl );
4254 break;
4255
4256 #if defined(MBEDTLS_SSL_PROTO_DTLS)
4257 case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
4258 return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
4259 #endif
4260
4261 /*
4262 * ==> ServerHello
4263 * Certificate
4264 * ( ServerKeyExchange )
4265 * ( CertificateRequest )
4266 * ServerHelloDone
4267 */
4268 case MBEDTLS_SSL_SERVER_HELLO:
4269 ret = ssl_write_server_hello( ssl );
4270 break;
4271
4272 case MBEDTLS_SSL_SERVER_CERTIFICATE:
4273 ret = mbedtls_ssl_write_certificate( ssl );
4274 break;
4275
4276 case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
4277 ret = ssl_write_server_key_exchange( ssl );
4278 break;
4279
4280 case MBEDTLS_SSL_CERTIFICATE_REQUEST:
4281 ret = ssl_write_certificate_request( ssl );
4282 break;
4283
4284 case MBEDTLS_SSL_SERVER_HELLO_DONE:
4285 ret = ssl_write_server_hello_done( ssl );
4286 break;
4287
4288 /*
4289 * <== ( Certificate/Alert )
4290 * ClientKeyExchange
4291 * ( CertificateVerify )
4292 * ChangeCipherSpec
4293 * Finished
4294 */
4295 case MBEDTLS_SSL_CLIENT_CERTIFICATE:
4296 ret = mbedtls_ssl_parse_certificate( ssl );
4297 break;
4298
4299 case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
4300 ret = ssl_parse_client_key_exchange( ssl );
4301 break;
4302
4303 case MBEDTLS_SSL_CERTIFICATE_VERIFY:
4304 ret = ssl_parse_certificate_verify( ssl );
4305 break;
4306
4307 case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
4308 ret = mbedtls_ssl_parse_change_cipher_spec( ssl );
4309 break;
4310
4311 case MBEDTLS_SSL_CLIENT_FINISHED:
4312 ret = mbedtls_ssl_parse_finished( ssl );
4313 break;
4314
4315 /*
4316 * ==> ( NewSessionTicket )
4317 * ChangeCipherSpec
4318 * Finished
4319 */
4320 case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
4321 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
4322 if( ssl->handshake->new_session_ticket != 0 )
4323 ret = ssl_write_new_session_ticket( ssl );
4324 else
4325 #endif
4326 ret = mbedtls_ssl_write_change_cipher_spec( ssl );
4327 break;
4328
4329 case MBEDTLS_SSL_SERVER_FINISHED:
4330 ret = mbedtls_ssl_write_finished( ssl );
4331 break;
4332
4333 case MBEDTLS_SSL_FLUSH_BUFFERS:
4334 MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
4335 ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
4336 break;
4337
4338 case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
4339 mbedtls_ssl_handshake_wrapup( ssl );
4340 break;
4341
4342 default:
4343 MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
4344 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
4345 }
4346
4347 return( ret );
4348 }
4349
mbedtls_ssl_conf_preference_order(mbedtls_ssl_config * conf,int order)4350 void mbedtls_ssl_conf_preference_order( mbedtls_ssl_config *conf, int order )
4351 {
4352 conf->respect_cli_pref = order;
4353 }
4354
4355 #endif /* MBEDTLS_SSL_SRV_C */
4356