1 /* $OpenBSD: tls13_lib.c,v 1.65 2022/07/17 15:51:06 jsing Exp $ */ 2 /* 3 * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org> 4 * Copyright (c) 2019 Bob Beck <beck@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <stddef.h> 20 21 #include <openssl/evp.h> 22 23 #include "ssl_locl.h" 24 #include "ssl_tlsext.h" 25 #include "tls13_internal.h" 26 27 /* 28 * Downgrade sentinels - RFC 8446 section 4.1.3, magic values which must be set 29 * by the server in server random if it is willing to downgrade but supports 30 * TLSv1.3 31 */ 32 const uint8_t tls13_downgrade_12[8] = { 33 0x44, 0x4f, 0x57, 0x4e, 0x47, 0x52, 0x44, 0x01, 34 }; 35 const uint8_t tls13_downgrade_11[8] = { 36 0x44, 0x4f, 0x57, 0x4e, 0x47, 0x52, 0x44, 0x00, 37 }; 38 39 /* 40 * HelloRetryRequest hash - RFC 8446 section 4.1.3. 41 */ 42 const uint8_t tls13_hello_retry_request_hash[32] = { 43 0xcf, 0x21, 0xad, 0x74, 0xe5, 0x9a, 0x61, 0x11, 44 0xbe, 0x1d, 0x8c, 0x02, 0x1e, 0x65, 0xb8, 0x91, 45 0xc2, 0xa2, 0x11, 0x16, 0x7a, 0xbb, 0x8c, 0x5e, 46 0x07, 0x9e, 0x09, 0xe2, 0xc8, 0xa8, 0x33, 0x9c, 47 }; 48 49 /* 50 * Certificate Verify padding - RFC 8446 section 4.4.3. 51 */ 52 const uint8_t tls13_cert_verify_pad[64] = { 53 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 54 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 55 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 56 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 57 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 58 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 59 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 60 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 61 }; 62 63 const uint8_t tls13_cert_client_verify_context[] = 64 "TLS 1.3, client CertificateVerify"; 65 const uint8_t tls13_cert_server_verify_context[] = 66 "TLS 1.3, server CertificateVerify"; 67 68 const EVP_AEAD * 69 tls13_cipher_aead(const SSL_CIPHER *cipher) 70 { 71 if (cipher == NULL) 72 return NULL; 73 if (cipher->algorithm_ssl != SSL_TLSV1_3) 74 return NULL; 75 76 switch (cipher->algorithm_enc) { 77 case SSL_AES128GCM: 78 return EVP_aead_aes_128_gcm(); 79 case SSL_AES256GCM: 80 return EVP_aead_aes_256_gcm(); 81 case SSL_CHACHA20POLY1305: 82 return EVP_aead_chacha20_poly1305(); 83 } 84 85 return NULL; 86 } 87 88 const EVP_MD * 89 tls13_cipher_hash(const SSL_CIPHER *cipher) 90 { 91 if (cipher == NULL) 92 return NULL; 93 if (cipher->algorithm_ssl != SSL_TLSV1_3) 94 return NULL; 95 96 switch (cipher->algorithm2) { 97 case SSL_HANDSHAKE_MAC_SHA256: 98 return EVP_sha256(); 99 case SSL_HANDSHAKE_MAC_SHA384: 100 return EVP_sha384(); 101 } 102 103 return NULL; 104 } 105 106 static void 107 tls13_alert_received_cb(uint8_t alert_desc, void *arg) 108 { 109 struct tls13_ctx *ctx = arg; 110 111 if (alert_desc == TLS13_ALERT_CLOSE_NOTIFY) { 112 ctx->close_notify_recv = 1; 113 ctx->ssl->internal->shutdown |= SSL_RECEIVED_SHUTDOWN; 114 ctx->ssl->s3->warn_alert = alert_desc; 115 return; 116 } 117 118 if (alert_desc == TLS13_ALERT_USER_CANCELED) { 119 /* 120 * We treat this as advisory, since a close_notify alert 121 * SHOULD follow this alert (RFC 8446 section 6.1). 122 */ 123 return; 124 } 125 126 /* All other alerts are treated as fatal in TLSv1.3. */ 127 ctx->ssl->s3->fatal_alert = alert_desc; 128 129 SSLerror(ctx->ssl, SSL_AD_REASON_OFFSET + alert_desc); 130 ERR_asprintf_error_data("SSL alert number %d", alert_desc); 131 132 SSL_CTX_remove_session(ctx->ssl->ctx, ctx->ssl->session); 133 } 134 135 static void 136 tls13_alert_sent_cb(uint8_t alert_desc, void *arg) 137 { 138 struct tls13_ctx *ctx = arg; 139 140 if (alert_desc == TLS13_ALERT_CLOSE_NOTIFY) { 141 ctx->close_notify_sent = 1; 142 return; 143 } 144 145 if (alert_desc == TLS13_ALERT_USER_CANCELED) { 146 return; 147 } 148 149 /* All other alerts are treated as fatal in TLSv1.3. */ 150 if (ctx->error.code == 0) 151 SSLerror(ctx->ssl, SSL_AD_REASON_OFFSET + alert_desc); 152 } 153 154 static void 155 tls13_legacy_handshake_message_recv_cb(void *arg) 156 { 157 struct tls13_ctx *ctx = arg; 158 SSL *s = ctx->ssl; 159 CBS cbs; 160 161 if (s->internal->msg_callback == NULL) 162 return; 163 164 tls13_handshake_msg_data(ctx->hs_msg, &cbs); 165 ssl_msg_callback(s, 0, SSL3_RT_HANDSHAKE, CBS_data(&cbs), CBS_len(&cbs)); 166 } 167 168 static void 169 tls13_legacy_handshake_message_sent_cb(void *arg) 170 { 171 struct tls13_ctx *ctx = arg; 172 SSL *s = ctx->ssl; 173 CBS cbs; 174 175 if (s->internal->msg_callback == NULL) 176 return; 177 178 tls13_handshake_msg_data(ctx->hs_msg, &cbs); 179 ssl_msg_callback(s, 1, SSL3_RT_HANDSHAKE, CBS_data(&cbs), CBS_len(&cbs)); 180 } 181 182 static void 183 tls13_legacy_info_cb(void *arg, int state, int ret) 184 { 185 struct tls13_ctx *ctx = arg; 186 SSL *s = ctx->ssl; 187 188 ssl_info_callback(s, state, ret); 189 } 190 191 static int 192 tls13_legacy_ocsp_status_recv_cb(void *arg) 193 { 194 struct tls13_ctx *ctx = arg; 195 SSL *s = ctx->ssl; 196 int ret; 197 198 if (s->ctx->internal->tlsext_status_cb == NULL) 199 return 1; 200 201 ret = s->ctx->internal->tlsext_status_cb(s, 202 s->ctx->internal->tlsext_status_arg); 203 if (ret < 0) { 204 ctx->alert = TLS13_ALERT_INTERNAL_ERROR; 205 SSLerror(s, ERR_R_MALLOC_FAILURE); 206 return 0; 207 } 208 if (ret == 0) { 209 ctx->alert = TLS13_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE; 210 SSLerror(s, SSL_R_INVALID_STATUS_RESPONSE); 211 return 0; 212 } 213 214 return 1; 215 } 216 217 static int 218 tls13_phh_update_local_traffic_secret(struct tls13_ctx *ctx) 219 { 220 struct tls13_secrets *secrets = ctx->hs->tls13.secrets; 221 222 if (ctx->mode == TLS13_HS_CLIENT) 223 return (tls13_update_client_traffic_secret(secrets) && 224 tls13_record_layer_set_write_traffic_key(ctx->rl, 225 &secrets->client_application_traffic)); 226 return (tls13_update_server_traffic_secret(secrets) && 227 tls13_record_layer_set_read_traffic_key(ctx->rl, 228 &secrets->server_application_traffic)); 229 } 230 231 static int 232 tls13_phh_update_peer_traffic_secret(struct tls13_ctx *ctx) 233 { 234 struct tls13_secrets *secrets = ctx->hs->tls13.secrets; 235 236 if (ctx->mode == TLS13_HS_CLIENT) 237 return (tls13_update_server_traffic_secret(secrets) && 238 tls13_record_layer_set_read_traffic_key(ctx->rl, 239 &secrets->server_application_traffic)); 240 return (tls13_update_client_traffic_secret(secrets) && 241 tls13_record_layer_set_write_traffic_key(ctx->rl, 242 &secrets->client_application_traffic)); 243 } 244 245 /* 246 * XXX arbitrarily chosen limit of 100 post handshake handshake 247 * messages in an hour - to avoid a hostile peer from constantly 248 * requesting certificates or key renegotiaitons, etc. 249 */ 250 static int 251 tls13_phh_limit_check(struct tls13_ctx *ctx) 252 { 253 time_t now = time(NULL); 254 255 if (ctx->phh_last_seen > now - TLS13_PHH_LIMIT_TIME) { 256 if (ctx->phh_count > TLS13_PHH_LIMIT) 257 return 0; 258 } else 259 ctx->phh_count = 0; 260 ctx->phh_count++; 261 ctx->phh_last_seen = now; 262 return 1; 263 } 264 265 static ssize_t 266 tls13_key_update_recv(struct tls13_ctx *ctx, CBS *cbs) 267 { 268 struct tls13_handshake_msg *hs_msg = NULL; 269 CBB cbb_hs; 270 CBS cbs_hs; 271 uint8_t alert = TLS13_ALERT_INTERNAL_ERROR; 272 uint8_t key_update_request; 273 ssize_t ret; 274 275 if (!CBS_get_u8(cbs, &key_update_request)) { 276 alert = TLS13_ALERT_DECODE_ERROR; 277 goto err; 278 } 279 if (CBS_len(cbs) != 0) { 280 alert = TLS13_ALERT_DECODE_ERROR; 281 goto err; 282 } 283 if (key_update_request > 1) { 284 alert = TLS13_ALERT_ILLEGAL_PARAMETER; 285 goto err; 286 } 287 288 if (!tls13_phh_update_peer_traffic_secret(ctx)) 289 goto err; 290 291 if (key_update_request == 0) 292 return TLS13_IO_SUCCESS; 293 294 /* key_update_request == 1 */ 295 if ((hs_msg = tls13_handshake_msg_new()) == NULL) 296 goto err; 297 if (!tls13_handshake_msg_start(hs_msg, &cbb_hs, TLS13_MT_KEY_UPDATE)) 298 goto err; 299 if (!CBB_add_u8(&cbb_hs, 0)) 300 goto err; 301 if (!tls13_handshake_msg_finish(hs_msg)) 302 goto err; 303 304 ctx->key_update_request = 1; 305 tls13_handshake_msg_data(hs_msg, &cbs_hs); 306 ret = tls13_record_layer_phh(ctx->rl, &cbs_hs); 307 308 tls13_handshake_msg_free(hs_msg); 309 hs_msg = NULL; 310 311 return ret; 312 313 err: 314 tls13_handshake_msg_free(hs_msg); 315 316 return tls13_send_alert(ctx->rl, alert); 317 } 318 319 static void 320 tls13_phh_done_cb(void *cb_arg) 321 { 322 struct tls13_ctx *ctx = cb_arg; 323 324 if (ctx->key_update_request) { 325 tls13_phh_update_local_traffic_secret(ctx); 326 ctx->key_update_request = 0; 327 } 328 } 329 330 static ssize_t 331 tls13_phh_received_cb(void *cb_arg, CBS *cbs) 332 { 333 ssize_t ret = TLS13_IO_FAILURE; 334 struct tls13_ctx *ctx = cb_arg; 335 CBS phh_cbs; 336 337 if (!tls13_phh_limit_check(ctx)) 338 return tls13_send_alert(ctx->rl, TLS13_ALERT_UNEXPECTED_MESSAGE); 339 340 if ((ctx->hs_msg == NULL) && 341 ((ctx->hs_msg = tls13_handshake_msg_new()) == NULL)) 342 return TLS13_IO_FAILURE; 343 344 if (!tls13_handshake_msg_set_buffer(ctx->hs_msg, cbs)) 345 return TLS13_IO_FAILURE; 346 347 if ((ret = tls13_handshake_msg_recv(ctx->hs_msg, ctx->rl)) 348 != TLS13_IO_SUCCESS) 349 return ret; 350 351 if (!tls13_handshake_msg_content(ctx->hs_msg, &phh_cbs)) 352 return TLS13_IO_FAILURE; 353 354 switch(tls13_handshake_msg_type(ctx->hs_msg)) { 355 case TLS13_MT_KEY_UPDATE: 356 ret = tls13_key_update_recv(ctx, &phh_cbs); 357 break; 358 case TLS13_MT_NEW_SESSION_TICKET: 359 /* XXX do nothing for now and ignore this */ 360 break; 361 case TLS13_MT_CERTIFICATE_REQUEST: 362 /* XXX add support if we choose to advertise this */ 363 /* FALLTHROUGH */ 364 default: 365 ret = TLS13_IO_FAILURE; /* XXX send alert */ 366 break; 367 } 368 369 tls13_handshake_msg_free(ctx->hs_msg); 370 ctx->hs_msg = NULL; 371 return ret; 372 } 373 374 static const struct tls13_record_layer_callbacks rl_callbacks = { 375 .wire_read = tls13_legacy_wire_read_cb, 376 .wire_write = tls13_legacy_wire_write_cb, 377 .wire_flush = tls13_legacy_wire_flush_cb, 378 .alert_recv = tls13_alert_received_cb, 379 .alert_sent = tls13_alert_sent_cb, 380 .phh_recv = tls13_phh_received_cb, 381 .phh_sent = tls13_phh_done_cb, 382 }; 383 384 struct tls13_ctx * 385 tls13_ctx_new(int mode, SSL *ssl) 386 { 387 struct tls13_ctx *ctx = NULL; 388 389 if ((ctx = calloc(sizeof(struct tls13_ctx), 1)) == NULL) 390 goto err; 391 392 ctx->hs = &ssl->s3->hs; 393 ctx->mode = mode; 394 ctx->ssl = ssl; 395 396 if ((ctx->rl = tls13_record_layer_new(&rl_callbacks, ctx)) == NULL) 397 goto err; 398 399 ctx->handshake_message_sent_cb = tls13_legacy_handshake_message_sent_cb; 400 ctx->handshake_message_recv_cb = tls13_legacy_handshake_message_recv_cb; 401 ctx->info_cb = tls13_legacy_info_cb; 402 ctx->ocsp_status_recv_cb = tls13_legacy_ocsp_status_recv_cb; 403 404 if (!SSL_is_quic(ssl)) 405 ctx->middlebox_compat = 1; 406 407 ssl->internal->tls13 = ctx; 408 409 return ctx; 410 411 err: 412 tls13_ctx_free(ctx); 413 414 return NULL; 415 } 416 417 void 418 tls13_ctx_free(struct tls13_ctx *ctx) 419 { 420 if (ctx == NULL) 421 return; 422 423 tls13_error_clear(&ctx->error); 424 tls13_record_layer_free(ctx->rl); 425 tls13_handshake_msg_free(ctx->hs_msg); 426 427 freezero(ctx, sizeof(struct tls13_ctx)); 428 } 429 430 int 431 tls13_cert_add(struct tls13_ctx *ctx, CBB *cbb, X509 *cert, 432 int (*build_extensions)(SSL *s, uint16_t msg_type, CBB *cbb)) 433 { 434 CBB cert_data, cert_exts; 435 uint8_t *data; 436 int cert_len; 437 438 if ((cert_len = i2d_X509(cert, NULL)) < 0) 439 return 0; 440 441 if (!CBB_add_u24_length_prefixed(cbb, &cert_data)) 442 return 0; 443 if (!CBB_add_space(&cert_data, &data, cert_len)) 444 return 0; 445 if (i2d_X509(cert, &data) != cert_len) 446 return 0; 447 if (build_extensions != NULL) { 448 if (!build_extensions(ctx->ssl, SSL_TLSEXT_MSG_CT, cbb)) 449 return 0; 450 } else { 451 if (!CBB_add_u16_length_prefixed(cbb, &cert_exts)) 452 return 0; 453 } 454 if (!CBB_flush(cbb)) 455 return 0; 456 457 return 1; 458 } 459 460 int 461 tls13_synthetic_handshake_message(struct tls13_ctx *ctx) 462 { 463 struct tls13_handshake_msg *hm = NULL; 464 unsigned char buf[EVP_MAX_MD_SIZE]; 465 size_t hash_len; 466 CBB cbb; 467 CBS cbs; 468 SSL *s = ctx->ssl; 469 int ret = 0; 470 471 /* 472 * Replace ClientHello with synthetic handshake message - see 473 * RFC 8446 section 4.4.1. 474 */ 475 if (!tls1_transcript_hash_init(s)) 476 goto err; 477 if (!tls1_transcript_hash_value(s, buf, sizeof(buf), &hash_len)) 478 goto err; 479 480 if ((hm = tls13_handshake_msg_new()) == NULL) 481 goto err; 482 if (!tls13_handshake_msg_start(hm, &cbb, TLS13_MT_MESSAGE_HASH)) 483 goto err; 484 if (!CBB_add_bytes(&cbb, buf, hash_len)) 485 goto err; 486 if (!tls13_handshake_msg_finish(hm)) 487 goto err; 488 489 tls13_handshake_msg_data(hm, &cbs); 490 491 tls1_transcript_reset(ctx->ssl); 492 if (!tls1_transcript_record(ctx->ssl, CBS_data(&cbs), CBS_len(&cbs))) 493 goto err; 494 495 ret = 1; 496 497 err: 498 tls13_handshake_msg_free(hm); 499 500 return ret; 501 } 502 503 int 504 tls13_clienthello_hash_init(struct tls13_ctx *ctx) 505 { 506 if (ctx->hs->tls13.clienthello_md_ctx != NULL) 507 return 0; 508 if ((ctx->hs->tls13.clienthello_md_ctx = EVP_MD_CTX_new()) == NULL) 509 return 0; 510 if (!EVP_DigestInit_ex(ctx->hs->tls13.clienthello_md_ctx, 511 EVP_sha256(), NULL)) 512 return 0; 513 514 if ((ctx->hs->tls13.clienthello_hash == NULL) && 515 (ctx->hs->tls13.clienthello_hash = calloc(1, EVP_MAX_MD_SIZE)) == 516 NULL) 517 return 0; 518 519 return 1; 520 } 521 522 void 523 tls13_clienthello_hash_clear(struct ssl_handshake_tls13_st *hs) /* XXX */ 524 { 525 EVP_MD_CTX_free(hs->clienthello_md_ctx); 526 hs->clienthello_md_ctx = NULL; 527 freezero(hs->clienthello_hash, EVP_MAX_MD_SIZE); 528 hs->clienthello_hash = NULL; 529 } 530 531 int 532 tls13_clienthello_hash_update_bytes(struct tls13_ctx *ctx, void *data, 533 size_t len) 534 { 535 return EVP_DigestUpdate(ctx->hs->tls13.clienthello_md_ctx, data, len); 536 } 537 538 int 539 tls13_clienthello_hash_update(struct tls13_ctx *ctx, CBS *cbs) 540 { 541 return tls13_clienthello_hash_update_bytes(ctx, (void *)CBS_data(cbs), 542 CBS_len(cbs)); 543 } 544 545 int 546 tls13_clienthello_hash_finalize(struct tls13_ctx *ctx) 547 { 548 if (!EVP_DigestFinal_ex(ctx->hs->tls13.clienthello_md_ctx, 549 ctx->hs->tls13.clienthello_hash, 550 &ctx->hs->tls13.clienthello_hash_len)) 551 return 0; 552 EVP_MD_CTX_free(ctx->hs->tls13.clienthello_md_ctx); 553 ctx->hs->tls13.clienthello_md_ctx = NULL; 554 return 1; 555 } 556 557 int 558 tls13_clienthello_hash_validate(struct tls13_ctx *ctx) 559 { 560 unsigned char new_ch_hash[EVP_MAX_MD_SIZE]; 561 unsigned int new_ch_hash_len; 562 563 if (ctx->hs->tls13.clienthello_hash == NULL) 564 return 0; 565 566 if (!EVP_DigestFinal_ex(ctx->hs->tls13.clienthello_md_ctx, 567 new_ch_hash, &new_ch_hash_len)) 568 return 0; 569 EVP_MD_CTX_free(ctx->hs->tls13.clienthello_md_ctx); 570 ctx->hs->tls13.clienthello_md_ctx = NULL; 571 572 if (ctx->hs->tls13.clienthello_hash_len != new_ch_hash_len) 573 return 0; 574 if (memcmp(ctx->hs->tls13.clienthello_hash, new_ch_hash, 575 new_ch_hash_len) != 0) 576 return 0; 577 578 return 1; 579 } 580 581 int 582 tls13_exporter(struct tls13_ctx *ctx, const uint8_t *label, size_t label_len, 583 const uint8_t *context_value, size_t context_value_len, uint8_t *out, 584 size_t out_len) 585 { 586 struct tls13_secret context, export_out, export_secret; 587 struct tls13_secrets *secrets = ctx->hs->tls13.secrets; 588 EVP_MD_CTX *md_ctx = NULL; 589 unsigned int md_out_len; 590 int md_len; 591 int ret = 0; 592 593 /* 594 * RFC 8446 Section 7.5. 595 */ 596 597 memset(&context, 0, sizeof(context)); 598 memset(&export_secret, 0, sizeof(export_secret)); 599 600 export_out.data = out; 601 export_out.len = out_len; 602 603 if (!ctx->handshake_completed) 604 return 0; 605 606 md_len = EVP_MD_size(secrets->digest); 607 if (md_len <= 0 || md_len > EVP_MAX_MD_SIZE) 608 goto err; 609 610 if (!tls13_secret_init(&export_secret, md_len)) 611 goto err; 612 if (!tls13_secret_init(&context, md_len)) 613 goto err; 614 615 /* In TLSv1.3 no context is equivalent to an empty context. */ 616 if (context_value == NULL) { 617 context_value = ""; 618 context_value_len = 0; 619 } 620 621 if ((md_ctx = EVP_MD_CTX_new()) == NULL) 622 goto err; 623 if (!EVP_DigestInit_ex(md_ctx, secrets->digest, NULL)) 624 goto err; 625 if (!EVP_DigestUpdate(md_ctx, context_value, context_value_len)) 626 goto err; 627 if (!EVP_DigestFinal_ex(md_ctx, context.data, &md_out_len)) 628 goto err; 629 if (md_len != md_out_len) 630 goto err; 631 632 if (!tls13_derive_secret_with_label_length(&export_secret, 633 secrets->digest, &secrets->exporter_master, label, label_len, 634 &secrets->empty_hash)) 635 goto err; 636 637 if (!tls13_hkdf_expand_label(&export_out, secrets->digest, 638 &export_secret, "exporter", &context)) 639 goto err; 640 641 ret = 1; 642 643 err: 644 EVP_MD_CTX_free(md_ctx); 645 tls13_secret_cleanup(&context); 646 tls13_secret_cleanup(&export_secret); 647 648 return ret; 649 } 650