1 /*
2 * TLS 1.3 functionality shared between client and server
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 */
7
8 #include "common.h"
9
10 #if defined(MBEDTLS_SSL_TLS_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3)
11
12 #include <string.h>
13
14 #include "mbedtls/error.h"
15 #include "debug_internal.h"
16 #include "mbedtls/oid.h"
17 #include "mbedtls/platform.h"
18 #include "mbedtls/constant_time.h"
19 #include "psa/crypto.h"
20 #include "mbedtls/psa_util.h"
21
22 #include "ssl_misc.h"
23 #include "ssl_tls13_invasive.h"
24 #include "ssl_tls13_keys.h"
25 #include "ssl_debug_helpers.h"
26
27 #include "psa/crypto.h"
28 #include "psa_util_internal.h"
29
30 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
31 /* Define a local translating function to save code size by not using too many
32 * arguments in each translating place. */
local_err_translation(psa_status_t status)33 static int local_err_translation(psa_status_t status)
34 {
35 return psa_status_to_mbedtls(status, psa_to_ssl_errors,
36 ARRAY_LENGTH(psa_to_ssl_errors),
37 psa_generic_status_to_mbedtls);
38 }
39 #define PSA_TO_MBEDTLS_ERR(status) local_err_translation(status)
40 #endif
41
42 const uint8_t mbedtls_ssl_tls13_hello_retry_request_magic[
43 MBEDTLS_SERVER_HELLO_RANDOM_LEN] =
44 { 0xCF, 0x21, 0xAD, 0x74, 0xE5, 0x9A, 0x61, 0x11,
45 0xBE, 0x1D, 0x8C, 0x02, 0x1E, 0x65, 0xB8, 0x91,
46 0xC2, 0xA2, 0x11, 0x16, 0x7A, 0xBB, 0x8C, 0x5E,
47 0x07, 0x9E, 0x09, 0xE2, 0xC8, 0xA8, 0x33, 0x9C };
48
mbedtls_ssl_tls13_fetch_handshake_msg(mbedtls_ssl_context * ssl,unsigned hs_type,unsigned char ** buf,size_t * buf_len)49 int mbedtls_ssl_tls13_fetch_handshake_msg(mbedtls_ssl_context *ssl,
50 unsigned hs_type,
51 unsigned char **buf,
52 size_t *buf_len)
53 {
54 int ret;
55
56 if ((ret = mbedtls_ssl_read_record(ssl, 0)) != 0) {
57 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_read_record", ret);
58 goto cleanup;
59 }
60
61 if (ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
62 ssl->in_msg[0] != hs_type) {
63 MBEDTLS_SSL_DEBUG_MSG(1, ("Receive unexpected handshake message."));
64 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
65 MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE);
66 ret = MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
67 goto cleanup;
68 }
69
70 /*
71 * Jump handshake header (4 bytes, see Section 4 of RFC 8446).
72 * ...
73 * HandshakeType msg_type;
74 * uint24 length;
75 * ...
76 */
77 *buf = ssl->in_msg + 4;
78 *buf_len = ssl->in_hslen - 4;
79
80 cleanup:
81
82 return ret;
83 }
84
mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts(mbedtls_ssl_context * ssl,const unsigned char * buf,const unsigned char * end,const unsigned char ** supported_versions_data,const unsigned char ** supported_versions_data_end)85 int mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts(
86 mbedtls_ssl_context *ssl,
87 const unsigned char *buf, const unsigned char *end,
88 const unsigned char **supported_versions_data,
89 const unsigned char **supported_versions_data_end)
90 {
91 const unsigned char *p = buf;
92 size_t extensions_len;
93 const unsigned char *extensions_end;
94
95 *supported_versions_data = NULL;
96 *supported_versions_data_end = NULL;
97
98 /* Case of no extension */
99 if (p == end) {
100 return 0;
101 }
102
103 /* ...
104 * Extension extensions<x..2^16-1>;
105 * ...
106 * struct {
107 * ExtensionType extension_type; (2 bytes)
108 * opaque extension_data<0..2^16-1>;
109 * } Extension;
110 */
111 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
112 extensions_len = MBEDTLS_GET_UINT16_BE(p, 0);
113 p += 2;
114
115 /* Check extensions do not go beyond the buffer of data. */
116 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, extensions_len);
117 extensions_end = p + extensions_len;
118
119 while (p < extensions_end) {
120 unsigned int extension_type;
121 size_t extension_data_len;
122
123 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, 4);
124 extension_type = MBEDTLS_GET_UINT16_BE(p, 0);
125 extension_data_len = MBEDTLS_GET_UINT16_BE(p, 2);
126 p += 4;
127 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, extension_data_len);
128
129 if (extension_type == MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS) {
130 *supported_versions_data = p;
131 *supported_versions_data_end = p + extension_data_len;
132 return 1;
133 }
134 p += extension_data_len;
135 }
136
137 return 0;
138 }
139
140 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
141 /*
142 * STATE HANDLING: Read CertificateVerify
143 */
144 /* Macro to express the maximum length of the verify structure.
145 *
146 * The structure is computed per TLS 1.3 specification as:
147 * - 64 bytes of octet 32,
148 * - 33 bytes for the context string
149 * (which is either "TLS 1.3, client CertificateVerify"
150 * or "TLS 1.3, server CertificateVerify"),
151 * - 1 byte for the octet 0x0, which serves as a separator,
152 * - 32 or 48 bytes for the Transcript-Hash(Handshake Context, Certificate)
153 * (depending on the size of the transcript_hash)
154 *
155 * This results in a total size of
156 * - 130 bytes for a SHA256-based transcript hash, or
157 * (64 + 33 + 1 + 32 bytes)
158 * - 146 bytes for a SHA384-based transcript hash.
159 * (64 + 33 + 1 + 48 bytes)
160 *
161 */
162 #define SSL_VERIFY_STRUCT_MAX_SIZE (64 + \
163 33 + \
164 1 + \
165 MBEDTLS_TLS1_3_MD_MAX_SIZE \
166 )
167
168 /*
169 * The ssl_tls13_create_verify_structure() creates the verify structure.
170 * As input, it requires the transcript hash.
171 *
172 * The caller has to ensure that the buffer has size at least
173 * SSL_VERIFY_STRUCT_MAX_SIZE bytes.
174 */
ssl_tls13_create_verify_structure(const unsigned char * transcript_hash,size_t transcript_hash_len,unsigned char * verify_buffer,size_t * verify_buffer_len,int from)175 static void ssl_tls13_create_verify_structure(const unsigned char *transcript_hash,
176 size_t transcript_hash_len,
177 unsigned char *verify_buffer,
178 size_t *verify_buffer_len,
179 int from)
180 {
181 size_t idx;
182
183 /* RFC 8446, Section 4.4.3:
184 *
185 * The digital signature [in the CertificateVerify message] is then
186 * computed over the concatenation of:
187 * - A string that consists of octet 32 (0x20) repeated 64 times
188 * - The context string
189 * - A single 0 byte which serves as the separator
190 * - The content to be signed
191 */
192 memset(verify_buffer, 0x20, 64);
193 idx = 64;
194
195 if (from == MBEDTLS_SSL_IS_CLIENT) {
196 memcpy(verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(client_cv));
197 idx += MBEDTLS_SSL_TLS1_3_LBL_LEN(client_cv);
198 } else { /* from == MBEDTLS_SSL_IS_SERVER */
199 memcpy(verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(server_cv));
200 idx += MBEDTLS_SSL_TLS1_3_LBL_LEN(server_cv);
201 }
202
203 verify_buffer[idx++] = 0x0;
204
205 memcpy(verify_buffer + idx, transcript_hash, transcript_hash_len);
206 idx += transcript_hash_len;
207
208 *verify_buffer_len = idx;
209 }
210
211 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_parse_certificate_verify(mbedtls_ssl_context * ssl,const unsigned char * buf,const unsigned char * end,const unsigned char * verify_buffer,size_t verify_buffer_len)212 static int ssl_tls13_parse_certificate_verify(mbedtls_ssl_context *ssl,
213 const unsigned char *buf,
214 const unsigned char *end,
215 const unsigned char *verify_buffer,
216 size_t verify_buffer_len)
217 {
218 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
219 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
220 const unsigned char *p = buf;
221 uint16_t algorithm;
222 size_t signature_len;
223 mbedtls_pk_type_t sig_alg;
224 mbedtls_md_type_t md_alg;
225 psa_algorithm_t hash_alg = PSA_ALG_NONE;
226 unsigned char verify_hash[PSA_HASH_MAX_SIZE];
227 size_t verify_hash_len;
228
229 void const *options = NULL;
230 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
231 mbedtls_pk_rsassa_pss_options rsassa_pss_options;
232 #endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
233
234 /*
235 * struct {
236 * SignatureScheme algorithm;
237 * opaque signature<0..2^16-1>;
238 * } CertificateVerify;
239 */
240 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
241 algorithm = MBEDTLS_GET_UINT16_BE(p, 0);
242 p += 2;
243
244 /* RFC 8446 section 4.4.3
245 *
246 * If the CertificateVerify message is sent by a server, the signature
247 * algorithm MUST be one offered in the client's "signature_algorithms"
248 * extension unless no valid certificate chain can be produced without
249 * unsupported algorithms
250 *
251 * RFC 8446 section 4.4.2.2
252 *
253 * If the client cannot construct an acceptable chain using the provided
254 * certificates and decides to abort the handshake, then it MUST abort the
255 * handshake with an appropriate certificate-related alert
256 * (by default, "unsupported_certificate").
257 *
258 * Check if algorithm is an offered signature algorithm.
259 */
260 if (!mbedtls_ssl_sig_alg_is_offered(ssl, algorithm)) {
261 /* algorithm not in offered signature algorithms list */
262 MBEDTLS_SSL_DEBUG_MSG(1, ("Received signature algorithm(%04x) is not "
263 "offered.",
264 (unsigned int) algorithm));
265 goto error;
266 }
267
268 if (mbedtls_ssl_get_pk_type_and_md_alg_from_sig_alg(
269 algorithm, &sig_alg, &md_alg) != 0) {
270 goto error;
271 }
272
273 hash_alg = mbedtls_md_psa_alg_from_type(md_alg);
274 if (hash_alg == 0) {
275 goto error;
276 }
277
278 MBEDTLS_SSL_DEBUG_MSG(3, ("Certificate Verify: Signature algorithm ( %04x )",
279 (unsigned int) algorithm));
280
281 /*
282 * Check the certificate's key type matches the signature alg
283 */
284 if (!mbedtls_pk_can_do(&ssl->session_negotiate->peer_cert->pk, sig_alg)) {
285 MBEDTLS_SSL_DEBUG_MSG(1, ("signature algorithm doesn't match cert key"));
286 goto error;
287 }
288
289 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
290 signature_len = MBEDTLS_GET_UINT16_BE(p, 0);
291 p += 2;
292 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, signature_len);
293
294 status = psa_hash_compute(hash_alg,
295 verify_buffer,
296 verify_buffer_len,
297 verify_hash,
298 sizeof(verify_hash),
299 &verify_hash_len);
300 if (status != PSA_SUCCESS) {
301 MBEDTLS_SSL_DEBUG_RET(1, "hash computation PSA error", status);
302 goto error;
303 }
304
305 MBEDTLS_SSL_DEBUG_BUF(3, "verify hash", verify_hash, verify_hash_len);
306 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
307 if (sig_alg == MBEDTLS_PK_RSASSA_PSS) {
308 rsassa_pss_options.mgf1_hash_id = md_alg;
309
310 rsassa_pss_options.expected_salt_len = PSA_HASH_LENGTH(hash_alg);
311 options = (const void *) &rsassa_pss_options;
312 }
313 #endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
314
315 if ((ret = mbedtls_pk_verify_ext(sig_alg, options,
316 &ssl->session_negotiate->peer_cert->pk,
317 md_alg, verify_hash, verify_hash_len,
318 p, signature_len)) == 0) {
319 return 0;
320 }
321 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_pk_verify_ext", ret);
322
323 error:
324 /* RFC 8446 section 4.4.3
325 *
326 * If the verification fails, the receiver MUST terminate the handshake
327 * with a "decrypt_error" alert.
328 */
329 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR,
330 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE);
331 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
332
333 }
334 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
335
mbedtls_ssl_tls13_process_certificate_verify(mbedtls_ssl_context * ssl)336 int mbedtls_ssl_tls13_process_certificate_verify(mbedtls_ssl_context *ssl)
337 {
338
339 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
340 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
341 unsigned char verify_buffer[SSL_VERIFY_STRUCT_MAX_SIZE];
342 size_t verify_buffer_len;
343 unsigned char transcript[MBEDTLS_TLS1_3_MD_MAX_SIZE];
344 size_t transcript_len;
345 unsigned char *buf;
346 size_t buf_len;
347
348 MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate verify"));
349
350 MBEDTLS_SSL_PROC_CHK(
351 mbedtls_ssl_tls13_fetch_handshake_msg(
352 ssl, MBEDTLS_SSL_HS_CERTIFICATE_VERIFY, &buf, &buf_len));
353
354 /* Need to calculate the hash of the transcript first
355 * before reading the message since otherwise it gets
356 * included in the transcript
357 */
358 ret = mbedtls_ssl_get_handshake_transcript(
359 ssl,
360 (mbedtls_md_type_t) ssl->handshake->ciphersuite_info->mac,
361 transcript, sizeof(transcript),
362 &transcript_len);
363 if (ret != 0) {
364 MBEDTLS_SSL_PEND_FATAL_ALERT(
365 MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
366 MBEDTLS_ERR_SSL_INTERNAL_ERROR);
367 return ret;
368 }
369
370 MBEDTLS_SSL_DEBUG_BUF(3, "handshake hash", transcript, transcript_len);
371
372 /* Create verify structure */
373 ssl_tls13_create_verify_structure(transcript,
374 transcript_len,
375 verify_buffer,
376 &verify_buffer_len,
377 (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) ?
378 MBEDTLS_SSL_IS_SERVER :
379 MBEDTLS_SSL_IS_CLIENT);
380
381 /* Process the message contents */
382 MBEDTLS_SSL_PROC_CHK(ssl_tls13_parse_certificate_verify(
383 ssl, buf, buf + buf_len,
384 verify_buffer, verify_buffer_len));
385
386 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
387 ssl, MBEDTLS_SSL_HS_CERTIFICATE_VERIFY,
388 buf, buf_len));
389
390 cleanup:
391
392 MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse certificate verify"));
393 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_tls13_process_certificate_verify", ret);
394 return ret;
395 #else
396 ((void) ssl);
397 MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
398 return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
399 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
400 }
401
402 /*
403 *
404 * STATE HANDLING: Incoming Certificate.
405 *
406 */
407
408 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
409 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
410 /*
411 * Structure of Certificate message:
412 *
413 * enum {
414 * X509(0),
415 * RawPublicKey(2),
416 * (255)
417 * } CertificateType;
418 *
419 * struct {
420 * select (certificate_type) {
421 * case RawPublicKey:
422 * * From RFC 7250 ASN.1_subjectPublicKeyInfo *
423 * opaque ASN1_subjectPublicKeyInfo<1..2^24-1>;
424 * case X509:
425 * opaque cert_data<1..2^24-1>;
426 * };
427 * Extension extensions<0..2^16-1>;
428 * } CertificateEntry;
429 *
430 * struct {
431 * opaque certificate_request_context<0..2^8-1>;
432 * CertificateEntry certificate_list<0..2^24-1>;
433 * } Certificate;
434 *
435 */
436
437 /* Parse certificate chain send by the server. */
438 MBEDTLS_CHECK_RETURN_CRITICAL
439 MBEDTLS_STATIC_TESTABLE
mbedtls_ssl_tls13_parse_certificate(mbedtls_ssl_context * ssl,const unsigned char * buf,const unsigned char * end)440 int mbedtls_ssl_tls13_parse_certificate(mbedtls_ssl_context *ssl,
441 const unsigned char *buf,
442 const unsigned char *end)
443 {
444 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
445 size_t certificate_request_context_len = 0;
446 size_t certificate_list_len = 0;
447 const unsigned char *p = buf;
448 const unsigned char *certificate_list_end;
449 mbedtls_ssl_handshake_params *handshake = ssl->handshake;
450
451 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 4);
452 certificate_request_context_len = p[0];
453 certificate_list_len = MBEDTLS_GET_UINT24_BE(p, 1);
454 p += 4;
455
456 /* In theory, the certificate list can be up to 2^24 Bytes, but we don't
457 * support anything beyond 2^16 = 64K.
458 */
459 if ((certificate_request_context_len != 0) ||
460 (certificate_list_len >= 0x10000)) {
461 MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate message"));
462 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
463 MBEDTLS_ERR_SSL_DECODE_ERROR);
464 return MBEDTLS_ERR_SSL_DECODE_ERROR;
465 }
466
467 /* In case we tried to reuse a session but it failed */
468 if (ssl->session_negotiate->peer_cert != NULL) {
469 mbedtls_x509_crt_free(ssl->session_negotiate->peer_cert);
470 mbedtls_free(ssl->session_negotiate->peer_cert);
471 }
472
473 if (certificate_list_len == 0) {
474 ssl->session_negotiate->peer_cert = NULL;
475 ret = 0;
476 goto exit;
477 }
478
479 if ((ssl->session_negotiate->peer_cert =
480 mbedtls_calloc(1, sizeof(mbedtls_x509_crt))) == NULL) {
481 MBEDTLS_SSL_DEBUG_MSG(1, ("alloc( %" MBEDTLS_PRINTF_SIZET " bytes ) failed",
482 sizeof(mbedtls_x509_crt)));
483 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
484 MBEDTLS_ERR_SSL_ALLOC_FAILED);
485 return MBEDTLS_ERR_SSL_ALLOC_FAILED;
486 }
487
488 mbedtls_x509_crt_init(ssl->session_negotiate->peer_cert);
489
490 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, certificate_list_len);
491 certificate_list_end = p + certificate_list_len;
492 while (p < certificate_list_end) {
493 size_t cert_data_len, extensions_len;
494 const unsigned char *extensions_end;
495
496 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, 3);
497 cert_data_len = MBEDTLS_GET_UINT24_BE(p, 0);
498 p += 3;
499
500 /* In theory, the CRT can be up to 2^24 Bytes, but we don't support
501 * anything beyond 2^16 = 64K. Otherwise as in the TLS 1.2 code,
502 * check that we have a minimum of 128 bytes of data, this is not
503 * clear why we need that though.
504 */
505 if ((cert_data_len < 128) || (cert_data_len >= 0x10000)) {
506 MBEDTLS_SSL_DEBUG_MSG(1, ("bad Certificate message"));
507 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
508 MBEDTLS_ERR_SSL_DECODE_ERROR);
509 return MBEDTLS_ERR_SSL_DECODE_ERROR;
510 }
511
512 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, cert_data_len);
513 ret = mbedtls_x509_crt_parse_der(ssl->session_negotiate->peer_cert,
514 p, cert_data_len);
515
516 switch (ret) {
517 case 0: /*ok*/
518 break;
519 case MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + MBEDTLS_ERR_OID_NOT_FOUND:
520 /* Ignore certificate with an unknown algorithm: maybe a
521 prior certificate was already trusted. */
522 break;
523
524 case MBEDTLS_ERR_X509_ALLOC_FAILED:
525 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
526 MBEDTLS_ERR_X509_ALLOC_FAILED);
527 MBEDTLS_SSL_DEBUG_RET(1, " mbedtls_x509_crt_parse_der", ret);
528 return ret;
529
530 case MBEDTLS_ERR_X509_UNKNOWN_VERSION:
531 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT,
532 MBEDTLS_ERR_X509_UNKNOWN_VERSION);
533 MBEDTLS_SSL_DEBUG_RET(1, " mbedtls_x509_crt_parse_der", ret);
534 return ret;
535
536 default:
537 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_BAD_CERT,
538 ret);
539 MBEDTLS_SSL_DEBUG_RET(1, " mbedtls_x509_crt_parse_der", ret);
540 return ret;
541 }
542
543 p += cert_data_len;
544
545 /* Certificate extensions length */
546 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, 2);
547 extensions_len = MBEDTLS_GET_UINT16_BE(p, 0);
548 p += 2;
549 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, extensions_len);
550
551 extensions_end = p + extensions_len;
552 handshake->received_extensions = MBEDTLS_SSL_EXT_MASK_NONE;
553
554 while (p < extensions_end) {
555 unsigned int extension_type;
556 size_t extension_data_len;
557
558 /*
559 * struct {
560 * ExtensionType extension_type; (2 bytes)
561 * opaque extension_data<0..2^16-1>;
562 * } Extension;
563 */
564 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, 4);
565 extension_type = MBEDTLS_GET_UINT16_BE(p, 0);
566 extension_data_len = MBEDTLS_GET_UINT16_BE(p, 2);
567 p += 4;
568
569 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, extension_data_len);
570
571 ret = mbedtls_ssl_tls13_check_received_extension(
572 ssl, MBEDTLS_SSL_HS_CERTIFICATE, extension_type,
573 MBEDTLS_SSL_TLS1_3_ALLOWED_EXTS_OF_CT);
574 if (ret != 0) {
575 return ret;
576 }
577
578 switch (extension_type) {
579 default:
580 MBEDTLS_SSL_PRINT_EXT(
581 3, MBEDTLS_SSL_HS_CERTIFICATE,
582 extension_type, "( ignored )");
583 break;
584 }
585
586 p += extension_data_len;
587 }
588
589 MBEDTLS_SSL_PRINT_EXTS(3, MBEDTLS_SSL_HS_CERTIFICATE,
590 handshake->received_extensions);
591 }
592
593 exit:
594 /* Check that all the message is consumed. */
595 if (p != end) {
596 MBEDTLS_SSL_DEBUG_MSG(1, ("bad Certificate message"));
597 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
598 MBEDTLS_ERR_SSL_DECODE_ERROR);
599 return MBEDTLS_ERR_SSL_DECODE_ERROR;
600 }
601
602 MBEDTLS_SSL_DEBUG_CRT(3, "peer certificate",
603 ssl->session_negotiate->peer_cert);
604
605 return ret;
606 }
607 #else
608 MBEDTLS_CHECK_RETURN_CRITICAL
609 MBEDTLS_STATIC_TESTABLE
mbedtls_ssl_tls13_parse_certificate(mbedtls_ssl_context * ssl,const unsigned char * buf,const unsigned char * end)610 int mbedtls_ssl_tls13_parse_certificate(mbedtls_ssl_context *ssl,
611 const unsigned char *buf,
612 const unsigned char *end)
613 {
614 ((void) ssl);
615 ((void) buf);
616 ((void) end);
617 return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
618 }
619 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
620 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
621
622 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
623 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
624 /* Validate certificate chain sent by the server. */
625 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_validate_certificate(mbedtls_ssl_context * ssl)626 static int ssl_tls13_validate_certificate(mbedtls_ssl_context *ssl)
627 {
628 int ret = 0;
629 int authmode = MBEDTLS_SSL_VERIFY_REQUIRED;
630 mbedtls_x509_crt *ca_chain;
631 mbedtls_x509_crl *ca_crl;
632 const char *ext_oid;
633 size_t ext_len;
634 uint32_t verify_result = 0;
635
636 /* If SNI was used, overwrite authentication mode
637 * from the configuration. */
638 #if defined(MBEDTLS_SSL_SRV_C)
639 if (ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER) {
640 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
641 if (ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET) {
642 authmode = ssl->handshake->sni_authmode;
643 } else
644 #endif
645 authmode = ssl->conf->authmode;
646 }
647 #endif
648
649 /*
650 * If the peer hasn't sent a certificate ( i.e. it sent
651 * an empty certificate chain ), this is reflected in the peer CRT
652 * structure being unset.
653 * Check for that and handle it depending on the
654 * authentication mode.
655 */
656 if (ssl->session_negotiate->peer_cert == NULL) {
657 MBEDTLS_SSL_DEBUG_MSG(1, ("peer has no certificate"));
658
659 #if defined(MBEDTLS_SSL_SRV_C)
660 if (ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER) {
661 /* The client was asked for a certificate but didn't send
662 * one. The client should know what's going on, so we
663 * don't send an alert.
664 */
665 ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
666 if (authmode == MBEDTLS_SSL_VERIFY_OPTIONAL) {
667 return 0;
668 } else {
669 MBEDTLS_SSL_PEND_FATAL_ALERT(
670 MBEDTLS_SSL_ALERT_MSG_NO_CERT,
671 MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE);
672 return MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE;
673 }
674 }
675 #endif /* MBEDTLS_SSL_SRV_C */
676
677 #if defined(MBEDTLS_SSL_CLI_C)
678 if (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) {
679 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_NO_CERT,
680 MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE);
681 return MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE;
682 }
683 #endif /* MBEDTLS_SSL_CLI_C */
684 }
685
686 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
687 if (ssl->handshake->sni_ca_chain != NULL) {
688 ca_chain = ssl->handshake->sni_ca_chain;
689 ca_crl = ssl->handshake->sni_ca_crl;
690 } else
691 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
692 {
693 ca_chain = ssl->conf->ca_chain;
694 ca_crl = ssl->conf->ca_crl;
695 }
696
697 /*
698 * Main check: verify certificate
699 */
700 ret = mbedtls_x509_crt_verify_with_profile(
701 ssl->session_negotiate->peer_cert,
702 ca_chain, ca_crl,
703 ssl->conf->cert_profile,
704 ssl->hostname,
705 &verify_result,
706 ssl->conf->f_vrfy, ssl->conf->p_vrfy);
707
708 if (ret != 0) {
709 MBEDTLS_SSL_DEBUG_RET(1, "x509_verify_cert", ret);
710 }
711
712 /*
713 * Secondary checks: always done, but change 'ret' only if it was 0
714 */
715 if (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) {
716 ext_oid = MBEDTLS_OID_SERVER_AUTH;
717 ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH);
718 } else {
719 ext_oid = MBEDTLS_OID_CLIENT_AUTH;
720 ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_CLIENT_AUTH);
721 }
722
723 if ((mbedtls_x509_crt_check_key_usage(
724 ssl->session_negotiate->peer_cert,
725 MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0) ||
726 (mbedtls_x509_crt_check_extended_key_usage(
727 ssl->session_negotiate->peer_cert,
728 ext_oid, ext_len) != 0)) {
729 MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (usage extensions)"));
730 if (ret == 0) {
731 ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
732 }
733 }
734
735 /* mbedtls_x509_crt_verify_with_profile is supposed to report a
736 * verification failure through MBEDTLS_ERR_X509_CERT_VERIFY_FAILED,
737 * with details encoded in the verification flags. All other kinds
738 * of error codes, including those from the user provided f_vrfy
739 * functions, are treated as fatal and lead to a failure of
740 * mbedtls_ssl_tls13_parse_certificate even if verification was optional.
741 */
742 if (authmode == MBEDTLS_SSL_VERIFY_OPTIONAL &&
743 (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
744 ret == MBEDTLS_ERR_SSL_BAD_CERTIFICATE)) {
745 ret = 0;
746 }
747
748 if (ca_chain == NULL && authmode == MBEDTLS_SSL_VERIFY_REQUIRED) {
749 MBEDTLS_SSL_DEBUG_MSG(1, ("got no CA chain"));
750 ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
751 }
752
753 if (ret != 0) {
754 /* The certificate may have been rejected for several reasons.
755 Pick one and send the corresponding alert. Which alert to send
756 may be a subject of debate in some cases. */
757 if (verify_result & MBEDTLS_X509_BADCERT_OTHER) {
758 MBEDTLS_SSL_PEND_FATAL_ALERT(
759 MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED, ret);
760 } else if (verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH) {
761 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_BAD_CERT, ret);
762 } else if (verify_result & (MBEDTLS_X509_BADCERT_KEY_USAGE |
763 MBEDTLS_X509_BADCERT_EXT_KEY_USAGE |
764 MBEDTLS_X509_BADCERT_NS_CERT_TYPE |
765 MBEDTLS_X509_BADCERT_BAD_PK |
766 MBEDTLS_X509_BADCERT_BAD_KEY)) {
767 MBEDTLS_SSL_PEND_FATAL_ALERT(
768 MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT, ret);
769 } else if (verify_result & MBEDTLS_X509_BADCERT_EXPIRED) {
770 MBEDTLS_SSL_PEND_FATAL_ALERT(
771 MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED, ret);
772 } else if (verify_result & MBEDTLS_X509_BADCERT_REVOKED) {
773 MBEDTLS_SSL_PEND_FATAL_ALERT(
774 MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED, ret);
775 } else if (verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED) {
776 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA, ret);
777 } else {
778 MBEDTLS_SSL_PEND_FATAL_ALERT(
779 MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN, ret);
780 }
781 }
782
783 #if defined(MBEDTLS_DEBUG_C)
784 if (verify_result != 0) {
785 MBEDTLS_SSL_DEBUG_MSG(3, ("! Certificate verification flags %08x",
786 (unsigned int) verify_result));
787 } else {
788 MBEDTLS_SSL_DEBUG_MSG(3, ("Certificate verification flags clear"));
789 }
790 #endif /* MBEDTLS_DEBUG_C */
791
792 ssl->session_negotiate->verify_result = verify_result;
793 return ret;
794 }
795 #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
796 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_validate_certificate(mbedtls_ssl_context * ssl)797 static int ssl_tls13_validate_certificate(mbedtls_ssl_context *ssl)
798 {
799 ((void) ssl);
800 return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
801 }
802 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
803 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
804
mbedtls_ssl_tls13_process_certificate(mbedtls_ssl_context * ssl)805 int mbedtls_ssl_tls13_process_certificate(mbedtls_ssl_context *ssl)
806 {
807 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
808 MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate"));
809
810 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
811 unsigned char *buf;
812 size_t buf_len;
813
814 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg(
815 ssl, MBEDTLS_SSL_HS_CERTIFICATE,
816 &buf, &buf_len));
817
818 /* Parse the certificate chain sent by the peer. */
819 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_parse_certificate(ssl, buf,
820 buf + buf_len));
821 /* Validate the certificate chain and set the verification results. */
822 MBEDTLS_SSL_PROC_CHK(ssl_tls13_validate_certificate(ssl));
823
824 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
825 ssl, MBEDTLS_SSL_HS_CERTIFICATE, buf, buf_len));
826
827 cleanup:
828 #else /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
829 (void) ssl;
830 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
831
832 MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse certificate"));
833 return ret;
834 }
835 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
836 /*
837 * enum {
838 * X509(0),
839 * RawPublicKey(2),
840 * (255)
841 * } CertificateType;
842 *
843 * struct {
844 * select (certificate_type) {
845 * case RawPublicKey:
846 * // From RFC 7250 ASN.1_subjectPublicKeyInfo
847 * opaque ASN1_subjectPublicKeyInfo<1..2^24-1>;
848 *
849 * case X509:
850 * opaque cert_data<1..2^24-1>;
851 * };
852 * Extension extensions<0..2^16-1>;
853 * } CertificateEntry;
854 *
855 * struct {
856 * opaque certificate_request_context<0..2^8-1>;
857 * CertificateEntry certificate_list<0..2^24-1>;
858 * } Certificate;
859 */
860 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_write_certificate_body(mbedtls_ssl_context * ssl,unsigned char * buf,unsigned char * end,size_t * out_len)861 static int ssl_tls13_write_certificate_body(mbedtls_ssl_context *ssl,
862 unsigned char *buf,
863 unsigned char *end,
864 size_t *out_len)
865 {
866 const mbedtls_x509_crt *crt = mbedtls_ssl_own_cert(ssl);
867 unsigned char *p = buf;
868 unsigned char *certificate_request_context =
869 ssl->handshake->certificate_request_context;
870 unsigned char certificate_request_context_len =
871 ssl->handshake->certificate_request_context_len;
872 unsigned char *p_certificate_list_len;
873
874
875 /* ...
876 * opaque certificate_request_context<0..2^8-1>;
877 * ...
878 */
879 MBEDTLS_SSL_CHK_BUF_PTR(p, end, certificate_request_context_len + 1);
880 *p++ = certificate_request_context_len;
881 if (certificate_request_context_len > 0) {
882 memcpy(p, certificate_request_context, certificate_request_context_len);
883 p += certificate_request_context_len;
884 }
885
886 /* ...
887 * CertificateEntry certificate_list<0..2^24-1>;
888 * ...
889 */
890 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 3);
891 p_certificate_list_len = p;
892 p += 3;
893
894 MBEDTLS_SSL_DEBUG_CRT(3, "own certificate", crt);
895
896 while (crt != NULL) {
897 size_t cert_data_len = crt->raw.len;
898
899 MBEDTLS_SSL_CHK_BUF_PTR(p, end, cert_data_len + 3 + 2);
900 MBEDTLS_PUT_UINT24_BE(cert_data_len, p, 0);
901 p += 3;
902
903 memcpy(p, crt->raw.p, cert_data_len);
904 p += cert_data_len;
905 crt = crt->next;
906
907 /* Currently, we don't have any certificate extensions defined.
908 * Hence, we are sending an empty extension with length zero.
909 */
910 MBEDTLS_PUT_UINT16_BE(0, p, 0);
911 p += 2;
912 }
913
914 MBEDTLS_PUT_UINT24_BE(p - p_certificate_list_len - 3,
915 p_certificate_list_len, 0);
916
917 *out_len = p - buf;
918
919 MBEDTLS_SSL_PRINT_EXTS(
920 3, MBEDTLS_SSL_HS_CERTIFICATE, ssl->handshake->sent_extensions);
921
922 return 0;
923 }
924
mbedtls_ssl_tls13_write_certificate(mbedtls_ssl_context * ssl)925 int mbedtls_ssl_tls13_write_certificate(mbedtls_ssl_context *ssl)
926 {
927 int ret;
928 unsigned char *buf;
929 size_t buf_len, msg_len;
930
931 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate"));
932
933 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg(
934 ssl, MBEDTLS_SSL_HS_CERTIFICATE, &buf, &buf_len));
935
936 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_certificate_body(ssl,
937 buf,
938 buf + buf_len,
939 &msg_len));
940
941 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
942 ssl, MBEDTLS_SSL_HS_CERTIFICATE, buf, msg_len));
943
944 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(
945 ssl, buf_len, msg_len));
946 cleanup:
947
948 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate"));
949 return ret;
950 }
951
952 /*
953 * STATE HANDLING: Output Certificate Verify
954 */
mbedtls_ssl_tls13_check_sig_alg_cert_key_match(uint16_t sig_alg,mbedtls_pk_context * key)955 int mbedtls_ssl_tls13_check_sig_alg_cert_key_match(uint16_t sig_alg,
956 mbedtls_pk_context *key)
957 {
958 mbedtls_pk_type_t pk_type = (mbedtls_pk_type_t) mbedtls_ssl_sig_from_pk(key);
959 size_t key_size = mbedtls_pk_get_bitlen(key);
960
961 switch (pk_type) {
962 case MBEDTLS_SSL_SIG_ECDSA:
963 switch (key_size) {
964 case 256:
965 return
966 sig_alg == MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256;
967
968 case 384:
969 return
970 sig_alg == MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384;
971
972 case 521:
973 return
974 sig_alg == MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512;
975 default:
976 break;
977 }
978 break;
979
980 case MBEDTLS_SSL_SIG_RSA:
981 switch (sig_alg) {
982 case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256: /* Intentional fallthrough */
983 case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384: /* Intentional fallthrough */
984 case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512:
985 return 1;
986
987 default:
988 break;
989 }
990 break;
991
992 default:
993 break;
994 }
995
996 return 0;
997 }
998
999 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_write_certificate_verify_body(mbedtls_ssl_context * ssl,unsigned char * buf,unsigned char * end,size_t * out_len)1000 static int ssl_tls13_write_certificate_verify_body(mbedtls_ssl_context *ssl,
1001 unsigned char *buf,
1002 unsigned char *end,
1003 size_t *out_len)
1004 {
1005 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1006 unsigned char *p = buf;
1007 mbedtls_pk_context *own_key;
1008
1009 unsigned char handshake_hash[MBEDTLS_TLS1_3_MD_MAX_SIZE];
1010 size_t handshake_hash_len;
1011 unsigned char verify_buffer[SSL_VERIFY_STRUCT_MAX_SIZE];
1012 size_t verify_buffer_len;
1013
1014 uint16_t *sig_alg = ssl->handshake->received_sig_algs;
1015 size_t signature_len = 0;
1016
1017 *out_len = 0;
1018
1019 own_key = mbedtls_ssl_own_key(ssl);
1020 if (own_key == NULL) {
1021 MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
1022 return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
1023 }
1024
1025 ret = mbedtls_ssl_get_handshake_transcript(
1026 ssl, (mbedtls_md_type_t) ssl->handshake->ciphersuite_info->mac,
1027 handshake_hash, sizeof(handshake_hash), &handshake_hash_len);
1028 if (ret != 0) {
1029 return ret;
1030 }
1031
1032 MBEDTLS_SSL_DEBUG_BUF(3, "handshake hash",
1033 handshake_hash,
1034 handshake_hash_len);
1035
1036 ssl_tls13_create_verify_structure(handshake_hash, handshake_hash_len,
1037 verify_buffer, &verify_buffer_len,
1038 ssl->conf->endpoint);
1039
1040 /*
1041 * struct {
1042 * SignatureScheme algorithm;
1043 * opaque signature<0..2^16-1>;
1044 * } CertificateVerify;
1045 */
1046 /* Check there is space for the algorithm identifier (2 bytes) and the
1047 * signature length (2 bytes).
1048 */
1049 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 4);
1050
1051 for (; *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++) {
1052 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
1053 mbedtls_pk_type_t pk_type = MBEDTLS_PK_NONE;
1054 mbedtls_md_type_t md_alg = MBEDTLS_MD_NONE;
1055 psa_algorithm_t psa_algorithm = PSA_ALG_NONE;
1056 unsigned char verify_hash[PSA_HASH_MAX_SIZE];
1057 size_t verify_hash_len;
1058
1059 if (!mbedtls_ssl_sig_alg_is_offered(ssl, *sig_alg)) {
1060 continue;
1061 }
1062
1063 if (!mbedtls_ssl_tls13_sig_alg_for_cert_verify_is_supported(*sig_alg)) {
1064 continue;
1065 }
1066
1067 if (!mbedtls_ssl_tls13_check_sig_alg_cert_key_match(*sig_alg, own_key)) {
1068 continue;
1069 }
1070
1071 if (mbedtls_ssl_get_pk_type_and_md_alg_from_sig_alg(
1072 *sig_alg, &pk_type, &md_alg) != 0) {
1073 return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
1074 }
1075
1076 /* Hash verify buffer with indicated hash function */
1077 psa_algorithm = mbedtls_md_psa_alg_from_type(md_alg);
1078 status = psa_hash_compute(psa_algorithm,
1079 verify_buffer,
1080 verify_buffer_len,
1081 verify_hash, sizeof(verify_hash),
1082 &verify_hash_len);
1083 if (status != PSA_SUCCESS) {
1084 return PSA_TO_MBEDTLS_ERR(status);
1085 }
1086
1087 MBEDTLS_SSL_DEBUG_BUF(3, "verify hash", verify_hash, verify_hash_len);
1088
1089 if ((ret = mbedtls_pk_sign_ext(pk_type, own_key,
1090 md_alg, verify_hash, verify_hash_len,
1091 p + 4, (size_t) (end - (p + 4)), &signature_len,
1092 ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
1093 MBEDTLS_SSL_DEBUG_MSG(2, ("CertificateVerify signature failed with %s",
1094 mbedtls_ssl_sig_alg_to_str(*sig_alg)));
1095 MBEDTLS_SSL_DEBUG_RET(2, "mbedtls_pk_sign_ext", ret);
1096
1097 /* The signature failed. This is possible if the private key
1098 * was not suitable for the signature operation as purposely we
1099 * did not check its suitability completely. Let's try with
1100 * another signature algorithm.
1101 */
1102 continue;
1103 }
1104
1105 MBEDTLS_SSL_DEBUG_MSG(2, ("CertificateVerify signature with %s",
1106 mbedtls_ssl_sig_alg_to_str(*sig_alg)));
1107
1108 break;
1109 }
1110
1111 if (*sig_alg == MBEDTLS_TLS1_3_SIG_NONE) {
1112 MBEDTLS_SSL_DEBUG_MSG(1, ("no suitable signature algorithm"));
1113 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE,
1114 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE);
1115 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
1116 }
1117
1118 MBEDTLS_PUT_UINT16_BE(*sig_alg, p, 0);
1119 MBEDTLS_PUT_UINT16_BE(signature_len, p, 2);
1120
1121 *out_len = 4 + signature_len;
1122
1123 return 0;
1124 }
1125
mbedtls_ssl_tls13_write_certificate_verify(mbedtls_ssl_context * ssl)1126 int mbedtls_ssl_tls13_write_certificate_verify(mbedtls_ssl_context *ssl)
1127 {
1128 int ret = 0;
1129 unsigned char *buf;
1130 size_t buf_len, msg_len;
1131
1132 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate verify"));
1133
1134 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg(
1135 ssl, MBEDTLS_SSL_HS_CERTIFICATE_VERIFY,
1136 &buf, &buf_len));
1137
1138 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_certificate_verify_body(
1139 ssl, buf, buf + buf_len, &msg_len));
1140
1141 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
1142 ssl, MBEDTLS_SSL_HS_CERTIFICATE_VERIFY,
1143 buf, msg_len));
1144
1145 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(
1146 ssl, buf_len, msg_len));
1147
1148 cleanup:
1149
1150 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate verify"));
1151 return ret;
1152 }
1153
1154 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
1155
1156 /*
1157 *
1158 * STATE HANDLING: Incoming Finished message.
1159 */
1160 /*
1161 * Implementation
1162 */
1163
1164 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_preprocess_finished_message(mbedtls_ssl_context * ssl)1165 static int ssl_tls13_preprocess_finished_message(mbedtls_ssl_context *ssl)
1166 {
1167 int ret;
1168
1169 ret = mbedtls_ssl_tls13_calculate_verify_data(
1170 ssl,
1171 ssl->handshake->state_local.finished_in.digest,
1172 sizeof(ssl->handshake->state_local.finished_in.digest),
1173 &ssl->handshake->state_local.finished_in.digest_len,
1174 ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ?
1175 MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT);
1176 if (ret != 0) {
1177 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_tls13_calculate_verify_data", ret);
1178 return ret;
1179 }
1180
1181 return 0;
1182 }
1183
1184 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_parse_finished_message(mbedtls_ssl_context * ssl,const unsigned char * buf,const unsigned char * end)1185 static int ssl_tls13_parse_finished_message(mbedtls_ssl_context *ssl,
1186 const unsigned char *buf,
1187 const unsigned char *end)
1188 {
1189 /*
1190 * struct {
1191 * opaque verify_data[Hash.length];
1192 * } Finished;
1193 */
1194 const unsigned char *expected_verify_data =
1195 ssl->handshake->state_local.finished_in.digest;
1196 size_t expected_verify_data_len =
1197 ssl->handshake->state_local.finished_in.digest_len;
1198 /* Structural validation */
1199 if ((size_t) (end - buf) != expected_verify_data_len) {
1200 MBEDTLS_SSL_DEBUG_MSG(1, ("bad finished message"));
1201
1202 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
1203 MBEDTLS_ERR_SSL_DECODE_ERROR);
1204 return MBEDTLS_ERR_SSL_DECODE_ERROR;
1205 }
1206
1207 MBEDTLS_SSL_DEBUG_BUF(4, "verify_data (self-computed):",
1208 expected_verify_data,
1209 expected_verify_data_len);
1210 MBEDTLS_SSL_DEBUG_BUF(4, "verify_data (received message):", buf,
1211 expected_verify_data_len);
1212
1213 /* Semantic validation */
1214 if (mbedtls_ct_memcmp(buf,
1215 expected_verify_data,
1216 expected_verify_data_len) != 0) {
1217 MBEDTLS_SSL_DEBUG_MSG(1, ("bad finished message"));
1218
1219 MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR,
1220 MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE);
1221 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
1222 }
1223 return 0;
1224 }
1225
mbedtls_ssl_tls13_process_finished_message(mbedtls_ssl_context * ssl)1226 int mbedtls_ssl_tls13_process_finished_message(mbedtls_ssl_context *ssl)
1227 {
1228 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1229 unsigned char *buf;
1230 size_t buf_len;
1231
1232 MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse finished message"));
1233
1234 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg(
1235 ssl, MBEDTLS_SSL_HS_FINISHED, &buf, &buf_len));
1236
1237 /* Preprocessing step: Compute handshake digest */
1238 MBEDTLS_SSL_PROC_CHK(ssl_tls13_preprocess_finished_message(ssl));
1239
1240 MBEDTLS_SSL_PROC_CHK(ssl_tls13_parse_finished_message(
1241 ssl, buf, buf + buf_len));
1242
1243 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
1244 ssl, MBEDTLS_SSL_HS_FINISHED, buf, buf_len));
1245
1246 cleanup:
1247
1248 MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse finished message"));
1249 return ret;
1250 }
1251
1252 /*
1253 *
1254 * STATE HANDLING: Write and send Finished message.
1255 *
1256 */
1257 /*
1258 * Implement
1259 */
1260
1261 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_prepare_finished_message(mbedtls_ssl_context * ssl)1262 static int ssl_tls13_prepare_finished_message(mbedtls_ssl_context *ssl)
1263 {
1264 int ret;
1265
1266 /* Compute transcript of handshake up to now. */
1267 ret = mbedtls_ssl_tls13_calculate_verify_data(ssl,
1268 ssl->handshake->state_local.finished_out.digest,
1269 sizeof(ssl->handshake->state_local.finished_out.
1270 digest),
1271 &ssl->handshake->state_local.finished_out.digest_len,
1272 ssl->conf->endpoint);
1273
1274 if (ret != 0) {
1275 MBEDTLS_SSL_DEBUG_RET(1, "calculate_verify_data failed", ret);
1276 return ret;
1277 }
1278
1279 return 0;
1280 }
1281
1282 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_write_finished_message_body(mbedtls_ssl_context * ssl,unsigned char * buf,unsigned char * end,size_t * out_len)1283 static int ssl_tls13_write_finished_message_body(mbedtls_ssl_context *ssl,
1284 unsigned char *buf,
1285 unsigned char *end,
1286 size_t *out_len)
1287 {
1288 size_t verify_data_len = ssl->handshake->state_local.finished_out.digest_len;
1289 /*
1290 * struct {
1291 * opaque verify_data[Hash.length];
1292 * } Finished;
1293 */
1294 MBEDTLS_SSL_CHK_BUF_PTR(buf, end, verify_data_len);
1295
1296 memcpy(buf, ssl->handshake->state_local.finished_out.digest,
1297 verify_data_len);
1298
1299 *out_len = verify_data_len;
1300 return 0;
1301 }
1302
1303 /* Main entry point: orchestrates the other functions */
mbedtls_ssl_tls13_write_finished_message(mbedtls_ssl_context * ssl)1304 int mbedtls_ssl_tls13_write_finished_message(mbedtls_ssl_context *ssl)
1305 {
1306 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1307 unsigned char *buf;
1308 size_t buf_len, msg_len;
1309
1310 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write finished message"));
1311
1312 MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_finished_message(ssl));
1313
1314 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg(ssl,
1315 MBEDTLS_SSL_HS_FINISHED, &buf, &buf_len));
1316
1317 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_finished_message_body(
1318 ssl, buf, buf + buf_len, &msg_len));
1319
1320 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(ssl,
1321 MBEDTLS_SSL_HS_FINISHED, buf, msg_len));
1322
1323 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(
1324 ssl, buf_len, msg_len));
1325 cleanup:
1326
1327 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write finished message"));
1328 return ret;
1329 }
1330
mbedtls_ssl_tls13_handshake_wrapup(mbedtls_ssl_context * ssl)1331 void mbedtls_ssl_tls13_handshake_wrapup(mbedtls_ssl_context *ssl)
1332 {
1333
1334 MBEDTLS_SSL_DEBUG_MSG(3, ("=> handshake wrapup"));
1335
1336 MBEDTLS_SSL_DEBUG_MSG(1, ("Switch to application keys for inbound traffic"));
1337 mbedtls_ssl_set_inbound_transform(ssl, ssl->transform_application);
1338
1339 MBEDTLS_SSL_DEBUG_MSG(1, ("Switch to application keys for outbound traffic"));
1340 mbedtls_ssl_set_outbound_transform(ssl, ssl->transform_application);
1341
1342 /*
1343 * Free the previous session and switch to the current one.
1344 */
1345 if (ssl->session) {
1346 mbedtls_ssl_session_free(ssl->session);
1347 mbedtls_free(ssl->session);
1348 }
1349 ssl->session = ssl->session_negotiate;
1350 ssl->session_negotiate = NULL;
1351
1352 MBEDTLS_SSL_DEBUG_MSG(3, ("<= handshake wrapup"));
1353 }
1354
1355 /*
1356 *
1357 * STATE HANDLING: Write ChangeCipherSpec
1358 *
1359 */
1360 #if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
1361 MBEDTLS_CHECK_RETURN_CRITICAL
ssl_tls13_write_change_cipher_spec_body(mbedtls_ssl_context * ssl,unsigned char * buf,unsigned char * end,size_t * olen)1362 static int ssl_tls13_write_change_cipher_spec_body(mbedtls_ssl_context *ssl,
1363 unsigned char *buf,
1364 unsigned char *end,
1365 size_t *olen)
1366 {
1367 ((void) ssl);
1368
1369 MBEDTLS_SSL_CHK_BUF_PTR(buf, end, 1);
1370 buf[0] = 1;
1371 *olen = 1;
1372
1373 return 0;
1374 }
1375
mbedtls_ssl_tls13_write_change_cipher_spec(mbedtls_ssl_context * ssl)1376 int mbedtls_ssl_tls13_write_change_cipher_spec(mbedtls_ssl_context *ssl)
1377 {
1378 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1379
1380 MBEDTLS_SSL_DEBUG_MSG(2, ("=> write change cipher spec"));
1381
1382 /* Only one CCS to send. */
1383 if (ssl->handshake->ccs_sent) {
1384 ret = 0;
1385 goto cleanup;
1386 }
1387
1388 /* Write CCS message */
1389 MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_change_cipher_spec_body(
1390 ssl, ssl->out_msg,
1391 ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
1392 &ssl->out_msglen));
1393
1394 ssl->out_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC;
1395
1396 /* Dispatch message */
1397 MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_write_record(ssl, 0));
1398
1399 ssl->handshake->ccs_sent = 1;
1400
1401 cleanup:
1402
1403 MBEDTLS_SSL_DEBUG_MSG(2, ("<= write change cipher spec"));
1404 return ret;
1405 }
1406
1407 #endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
1408
1409 /* Early Data Indication Extension
1410 *
1411 * struct {
1412 * select ( Handshake.msg_type ) {
1413 * case new_session_ticket: uint32 max_early_data_size;
1414 * case client_hello: Empty;
1415 * case encrypted_extensions: Empty;
1416 * };
1417 * } EarlyDataIndication;
1418 */
1419 #if defined(MBEDTLS_SSL_EARLY_DATA)
mbedtls_ssl_tls13_write_early_data_ext(mbedtls_ssl_context * ssl,int in_new_session_ticket,unsigned char * buf,const unsigned char * end,size_t * out_len)1420 int mbedtls_ssl_tls13_write_early_data_ext(mbedtls_ssl_context *ssl,
1421 int in_new_session_ticket,
1422 unsigned char *buf,
1423 const unsigned char *end,
1424 size_t *out_len)
1425 {
1426 unsigned char *p = buf;
1427
1428 #if defined(MBEDTLS_SSL_SRV_C)
1429 const size_t needed = in_new_session_ticket ? 8 : 4;
1430 #else
1431 const size_t needed = 4;
1432 ((void) in_new_session_ticket);
1433 #endif
1434
1435 *out_len = 0;
1436
1437 MBEDTLS_SSL_CHK_BUF_PTR(p, end, needed);
1438
1439 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_EARLY_DATA, p, 0);
1440 MBEDTLS_PUT_UINT16_BE(needed - 4, p, 2);
1441
1442 #if defined(MBEDTLS_SSL_SRV_C)
1443 if (in_new_session_ticket) {
1444 MBEDTLS_PUT_UINT32_BE(ssl->conf->max_early_data_size, p, 4);
1445 MBEDTLS_SSL_DEBUG_MSG(
1446 4, ("Sent max_early_data_size=%u",
1447 (unsigned int) ssl->conf->max_early_data_size));
1448 }
1449 #endif
1450
1451 *out_len = needed;
1452
1453 mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_EARLY_DATA);
1454
1455 return 0;
1456 }
1457
1458 #if defined(MBEDTLS_SSL_SRV_C)
mbedtls_ssl_tls13_check_early_data_len(mbedtls_ssl_context * ssl,size_t early_data_len)1459 int mbedtls_ssl_tls13_check_early_data_len(mbedtls_ssl_context *ssl,
1460 size_t early_data_len)
1461 {
1462 /*
1463 * This function should be called only while an handshake is in progress
1464 * and thus a session under negotiation. Add a sanity check to detect a
1465 * misuse.
1466 */
1467 if (ssl->session_negotiate == NULL) {
1468 return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
1469 }
1470
1471 /* RFC 8446 section 4.6.1
1472 *
1473 * A server receiving more than max_early_data_size bytes of 0-RTT data
1474 * SHOULD terminate the connection with an "unexpected_message" alert.
1475 * Note that if it is still possible to send early_data_len bytes of early
1476 * data, it means that early_data_len is smaller than max_early_data_size
1477 * (type uint32_t) and can fit in an uint32_t. We use this further
1478 * down.
1479 */
1480 if (early_data_len >
1481 (ssl->session_negotiate->max_early_data_size -
1482 ssl->total_early_data_size)) {
1483
1484 MBEDTLS_SSL_DEBUG_MSG(
1485 2, ("EarlyData: Too much early data received, %u + %" MBEDTLS_PRINTF_SIZET " > %u",
1486 ssl->total_early_data_size, early_data_len,
1487 ssl->session_negotiate->max_early_data_size));
1488
1489 MBEDTLS_SSL_PEND_FATAL_ALERT(
1490 MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
1491 MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE);
1492 return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
1493 }
1494
1495 /*
1496 * early_data_len has been checked to be less than max_early_data_size
1497 * that is uint32_t. Its cast to an uint32_t below is thus safe. We need
1498 * the cast to appease some compilers.
1499 */
1500 ssl->total_early_data_size += (uint32_t) early_data_len;
1501
1502 return 0;
1503 }
1504 #endif /* MBEDTLS_SSL_SRV_C */
1505 #endif /* MBEDTLS_SSL_EARLY_DATA */
1506
1507 /* Reset SSL context and update hash for handling HRR.
1508 *
1509 * Replace Transcript-Hash(X) by
1510 * Transcript-Hash( message_hash ||
1511 * 00 00 Hash.length ||
1512 * X )
1513 * A few states of the handshake are preserved, including:
1514 * - session ID
1515 * - session ticket
1516 * - negotiated ciphersuite
1517 */
mbedtls_ssl_reset_transcript_for_hrr(mbedtls_ssl_context * ssl)1518 int mbedtls_ssl_reset_transcript_for_hrr(mbedtls_ssl_context *ssl)
1519 {
1520 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
1521 unsigned char hash_transcript[PSA_HASH_MAX_SIZE + 4];
1522 size_t hash_len;
1523 const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
1524 ssl->handshake->ciphersuite_info;
1525
1526 MBEDTLS_SSL_DEBUG_MSG(3, ("Reset SSL session for HRR"));
1527
1528 ret = mbedtls_ssl_get_handshake_transcript(ssl, (mbedtls_md_type_t) ciphersuite_info->mac,
1529 hash_transcript + 4,
1530 PSA_HASH_MAX_SIZE,
1531 &hash_len);
1532 if (ret != 0) {
1533 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_get_handshake_transcript", ret);
1534 return ret;
1535 }
1536
1537 hash_transcript[0] = MBEDTLS_SSL_HS_MESSAGE_HASH;
1538 hash_transcript[1] = 0;
1539 hash_transcript[2] = 0;
1540 hash_transcript[3] = (unsigned char) hash_len;
1541
1542 hash_len += 4;
1543
1544 MBEDTLS_SSL_DEBUG_BUF(4, "Truncated handshake transcript",
1545 hash_transcript, hash_len);
1546
1547 /* Reset running hash and replace it with a hash of the transcript */
1548 ret = mbedtls_ssl_reset_checksum(ssl);
1549 if (ret != 0) {
1550 MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_reset_checksum", ret);
1551 return ret;
1552 }
1553 ret = ssl->handshake->update_checksum(ssl, hash_transcript, hash_len);
1554 if (ret != 0) {
1555 MBEDTLS_SSL_DEBUG_RET(1, "update_checksum", ret);
1556 return ret;
1557 }
1558
1559 return ret;
1560 }
1561
1562 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
1563
mbedtls_ssl_tls13_read_public_xxdhe_share(mbedtls_ssl_context * ssl,const unsigned char * buf,size_t buf_len)1564 int mbedtls_ssl_tls13_read_public_xxdhe_share(mbedtls_ssl_context *ssl,
1565 const unsigned char *buf,
1566 size_t buf_len)
1567 {
1568 uint8_t *p = (uint8_t *) buf;
1569 const uint8_t *end = buf + buf_len;
1570 mbedtls_ssl_handshake_params *handshake = ssl->handshake;
1571
1572 /* Get size of the TLS opaque key_exchange field of the KeyShareEntry struct. */
1573 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
1574 uint16_t peerkey_len = MBEDTLS_GET_UINT16_BE(p, 0);
1575 p += 2;
1576
1577 /* Check if key size is consistent with given buffer length. */
1578 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, peerkey_len);
1579
1580 /* Store peer's ECDH/FFDH public key. */
1581 if (peerkey_len > sizeof(handshake->xxdh_psa_peerkey)) {
1582 MBEDTLS_SSL_DEBUG_MSG(1, ("Invalid public key length: %u > %" MBEDTLS_PRINTF_SIZET,
1583 (unsigned) peerkey_len,
1584 sizeof(handshake->xxdh_psa_peerkey)));
1585 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
1586 }
1587 memcpy(handshake->xxdh_psa_peerkey, p, peerkey_len);
1588 handshake->xxdh_psa_peerkey_len = peerkey_len;
1589
1590 return 0;
1591 }
1592
1593 #if defined(PSA_WANT_ALG_FFDH)
mbedtls_ssl_get_psa_ffdh_info_from_tls_id(uint16_t tls_id,size_t * bits,psa_key_type_t * key_type)1594 static psa_status_t mbedtls_ssl_get_psa_ffdh_info_from_tls_id(
1595 uint16_t tls_id, size_t *bits, psa_key_type_t *key_type)
1596 {
1597 switch (tls_id) {
1598 #if defined(PSA_WANT_DH_RFC7919_2048)
1599 case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048:
1600 *bits = 2048;
1601 *key_type = PSA_KEY_TYPE_DH_KEY_PAIR(PSA_DH_FAMILY_RFC7919);
1602 return PSA_SUCCESS;
1603 #endif /* PSA_WANT_DH_RFC7919_2048 */
1604 #if defined(PSA_WANT_DH_RFC7919_3072)
1605 case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE3072:
1606 *bits = 3072;
1607 *key_type = PSA_KEY_TYPE_DH_KEY_PAIR(PSA_DH_FAMILY_RFC7919);
1608 return PSA_SUCCESS;
1609 #endif /* PSA_WANT_DH_RFC7919_3072 */
1610 #if defined(PSA_WANT_DH_RFC7919_4096)
1611 case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE4096:
1612 *bits = 4096;
1613 *key_type = PSA_KEY_TYPE_DH_KEY_PAIR(PSA_DH_FAMILY_RFC7919);
1614 return PSA_SUCCESS;
1615 #endif /* PSA_WANT_DH_RFC7919_4096 */
1616 #if defined(PSA_WANT_DH_RFC7919_6144)
1617 case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE6144:
1618 *bits = 6144;
1619 *key_type = PSA_KEY_TYPE_DH_KEY_PAIR(PSA_DH_FAMILY_RFC7919);
1620 return PSA_SUCCESS;
1621 #endif /* PSA_WANT_DH_RFC7919_6144 */
1622 #if defined(PSA_WANT_DH_RFC7919_8192)
1623 case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192:
1624 *bits = 8192;
1625 *key_type = PSA_KEY_TYPE_DH_KEY_PAIR(PSA_DH_FAMILY_RFC7919);
1626 return PSA_SUCCESS;
1627 #endif /* PSA_WANT_DH_RFC7919_8192 */
1628 default:
1629 return PSA_ERROR_NOT_SUPPORTED;
1630 }
1631 }
1632 #endif /* PSA_WANT_ALG_FFDH */
1633
mbedtls_ssl_tls13_generate_and_write_xxdh_key_exchange(mbedtls_ssl_context * ssl,uint16_t named_group,unsigned char * buf,unsigned char * end,size_t * out_len)1634 int mbedtls_ssl_tls13_generate_and_write_xxdh_key_exchange(
1635 mbedtls_ssl_context *ssl,
1636 uint16_t named_group,
1637 unsigned char *buf,
1638 unsigned char *end,
1639 size_t *out_len)
1640 {
1641 psa_status_t status = PSA_ERROR_GENERIC_ERROR;
1642 int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
1643 psa_key_attributes_t key_attributes;
1644 size_t own_pubkey_len;
1645 mbedtls_ssl_handshake_params *handshake = ssl->handshake;
1646 size_t bits = 0;
1647 psa_key_type_t key_type = PSA_KEY_TYPE_NONE;
1648 psa_algorithm_t alg = PSA_ALG_NONE;
1649 size_t buf_size = (size_t) (end - buf);
1650
1651 MBEDTLS_SSL_DEBUG_MSG(1, ("Perform PSA-based ECDH/FFDH computation."));
1652
1653 /* Convert EC's TLS ID to PSA key type. */
1654 #if defined(PSA_WANT_ALG_ECDH)
1655 if (mbedtls_ssl_get_psa_curve_info_from_tls_id(
1656 named_group, &key_type, &bits) == PSA_SUCCESS) {
1657 alg = PSA_ALG_ECDH;
1658 }
1659 #endif
1660 #if defined(PSA_WANT_ALG_FFDH)
1661 if (mbedtls_ssl_get_psa_ffdh_info_from_tls_id(named_group, &bits,
1662 &key_type) == PSA_SUCCESS) {
1663 alg = PSA_ALG_FFDH;
1664 }
1665 #endif
1666
1667 if (key_type == PSA_KEY_TYPE_NONE) {
1668 return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
1669 }
1670
1671 if (buf_size < PSA_BITS_TO_BYTES(bits)) {
1672 return MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
1673 }
1674
1675 handshake->xxdh_psa_type = key_type;
1676 ssl->handshake->xxdh_psa_bits = bits;
1677
1678 key_attributes = psa_key_attributes_init();
1679 psa_set_key_usage_flags(&key_attributes, PSA_KEY_USAGE_DERIVE);
1680 psa_set_key_algorithm(&key_attributes, alg);
1681 psa_set_key_type(&key_attributes, handshake->xxdh_psa_type);
1682 psa_set_key_bits(&key_attributes, handshake->xxdh_psa_bits);
1683
1684 /* Generate ECDH/FFDH private key. */
1685 status = psa_generate_key(&key_attributes,
1686 &handshake->xxdh_psa_privkey);
1687 if (status != PSA_SUCCESS) {
1688 ret = PSA_TO_MBEDTLS_ERR(status);
1689 MBEDTLS_SSL_DEBUG_RET(1, "psa_generate_key", ret);
1690 return ret;
1691
1692 }
1693
1694 /* Export the public part of the ECDH/FFDH private key from PSA. */
1695 status = psa_export_public_key(handshake->xxdh_psa_privkey,
1696 buf, buf_size,
1697 &own_pubkey_len);
1698
1699 if (status != PSA_SUCCESS) {
1700 ret = PSA_TO_MBEDTLS_ERR(status);
1701 MBEDTLS_SSL_DEBUG_RET(1, "psa_export_public_key", ret);
1702 return ret;
1703 }
1704
1705 *out_len = own_pubkey_len;
1706
1707 return 0;
1708 }
1709 #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */
1710
1711 /* RFC 8446 section 4.2
1712 *
1713 * If an implementation receives an extension which it recognizes and which is
1714 * not specified for the message in which it appears, it MUST abort the handshake
1715 * with an "illegal_parameter" alert.
1716 *
1717 */
mbedtls_ssl_tls13_check_received_extension(mbedtls_ssl_context * ssl,int hs_msg_type,unsigned int received_extension_type,uint32_t hs_msg_allowed_extensions_mask)1718 int mbedtls_ssl_tls13_check_received_extension(
1719 mbedtls_ssl_context *ssl,
1720 int hs_msg_type,
1721 unsigned int received_extension_type,
1722 uint32_t hs_msg_allowed_extensions_mask)
1723 {
1724 uint32_t extension_mask = mbedtls_ssl_get_extension_mask(
1725 received_extension_type);
1726
1727 MBEDTLS_SSL_PRINT_EXT(
1728 3, hs_msg_type, received_extension_type, "received");
1729
1730 if ((extension_mask & hs_msg_allowed_extensions_mask) == 0) {
1731 MBEDTLS_SSL_PRINT_EXT(
1732 3, hs_msg_type, received_extension_type, "is illegal");
1733 MBEDTLS_SSL_PEND_FATAL_ALERT(
1734 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
1735 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER);
1736 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
1737 }
1738
1739 ssl->handshake->received_extensions |= extension_mask;
1740 /*
1741 * If it is a message containing extension responses, check that we
1742 * previously sent the extension.
1743 */
1744 switch (hs_msg_type) {
1745 case MBEDTLS_SSL_HS_SERVER_HELLO:
1746 case MBEDTLS_SSL_TLS1_3_HS_HELLO_RETRY_REQUEST:
1747 case MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS:
1748 case MBEDTLS_SSL_HS_CERTIFICATE:
1749 /* Check if the received extension is sent by peer message.*/
1750 if ((ssl->handshake->sent_extensions & extension_mask) != 0) {
1751 return 0;
1752 }
1753 break;
1754 default:
1755 return 0;
1756 }
1757
1758 MBEDTLS_SSL_PRINT_EXT(
1759 3, hs_msg_type, received_extension_type, "is unsupported");
1760 MBEDTLS_SSL_PEND_FATAL_ALERT(
1761 MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT,
1762 MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION);
1763 return MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION;
1764 }
1765
1766 #if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT)
1767
1768 /* RFC 8449, section 4:
1769 *
1770 * The ExtensionData of the "record_size_limit" extension is
1771 * RecordSizeLimit:
1772 * uint16 RecordSizeLimit;
1773 */
1774 MBEDTLS_CHECK_RETURN_CRITICAL
mbedtls_ssl_tls13_parse_record_size_limit_ext(mbedtls_ssl_context * ssl,const unsigned char * buf,const unsigned char * end)1775 int mbedtls_ssl_tls13_parse_record_size_limit_ext(mbedtls_ssl_context *ssl,
1776 const unsigned char *buf,
1777 const unsigned char *end)
1778 {
1779 const unsigned char *p = buf;
1780 uint16_t record_size_limit;
1781 const size_t extension_data_len = end - buf;
1782
1783 if (extension_data_len !=
1784 MBEDTLS_SSL_RECORD_SIZE_LIMIT_EXTENSION_DATA_LENGTH) {
1785 MBEDTLS_SSL_DEBUG_MSG(2,
1786 ("record_size_limit extension has invalid length: %"
1787 MBEDTLS_PRINTF_SIZET " Bytes",
1788 extension_data_len));
1789
1790 MBEDTLS_SSL_PEND_FATAL_ALERT(
1791 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
1792 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER);
1793 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
1794 }
1795
1796 MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
1797 record_size_limit = MBEDTLS_GET_UINT16_BE(p, 0);
1798
1799 MBEDTLS_SSL_DEBUG_MSG(2, ("RecordSizeLimit: %u Bytes", record_size_limit));
1800
1801 /* RFC 8449, section 4:
1802 *
1803 * Endpoints MUST NOT send a "record_size_limit" extension with a value
1804 * smaller than 64. An endpoint MUST treat receipt of a smaller value
1805 * as a fatal error and generate an "illegal_parameter" alert.
1806 */
1807 if (record_size_limit < MBEDTLS_SSL_RECORD_SIZE_LIMIT_MIN) {
1808 MBEDTLS_SSL_DEBUG_MSG(1, ("Invalid record size limit : %u Bytes",
1809 record_size_limit));
1810 MBEDTLS_SSL_PEND_FATAL_ALERT(
1811 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
1812 MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER);
1813 return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
1814 }
1815
1816 ssl->session_negotiate->record_size_limit = record_size_limit;
1817
1818 return 0;
1819 }
1820
1821 MBEDTLS_CHECK_RETURN_CRITICAL
mbedtls_ssl_tls13_write_record_size_limit_ext(mbedtls_ssl_context * ssl,unsigned char * buf,const unsigned char * end,size_t * out_len)1822 int mbedtls_ssl_tls13_write_record_size_limit_ext(mbedtls_ssl_context *ssl,
1823 unsigned char *buf,
1824 const unsigned char *end,
1825 size_t *out_len)
1826 {
1827 unsigned char *p = buf;
1828 *out_len = 0;
1829
1830 MBEDTLS_STATIC_ASSERT(MBEDTLS_SSL_IN_CONTENT_LEN >= MBEDTLS_SSL_RECORD_SIZE_LIMIT_MIN,
1831 "MBEDTLS_SSL_IN_CONTENT_LEN is less than the "
1832 "minimum record size limit");
1833
1834 MBEDTLS_SSL_CHK_BUF_PTR(p, end, 6);
1835
1836 MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT, p, 0);
1837 MBEDTLS_PUT_UINT16_BE(MBEDTLS_SSL_RECORD_SIZE_LIMIT_EXTENSION_DATA_LENGTH,
1838 p, 2);
1839 MBEDTLS_PUT_UINT16_BE(MBEDTLS_SSL_IN_CONTENT_LEN, p, 4);
1840
1841 *out_len = 6;
1842
1843 MBEDTLS_SSL_DEBUG_MSG(2, ("Sent RecordSizeLimit: %d Bytes",
1844 MBEDTLS_SSL_IN_CONTENT_LEN));
1845
1846 mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT);
1847
1848 return 0;
1849 }
1850
1851 #endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */
1852
1853 #endif /* MBEDTLS_SSL_TLS_C && MBEDTLS_SSL_PROTO_TLS1_3 */
1854
