Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
/*
 * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdlib.h>
#include "ssl_local.h"
#include "internal/cryptlib.h"
#include <openssl/evp.h>
#include <openssl/kdf.h>

#define TLS13_MAX_LABEL_LEN     249

/* Always filled with zeros */
static const unsigned char default_zeros[EVP_MAX_MD_SIZE];

/*
 * Given a |secret|; a |label| of length |labellen|; and |data| of length
 * |datalen| (e.g. typically a hash of the handshake messages), derive a new
 * secret |outlen| bytes long and store it in the location pointed to be |out|.
 * The |data| value may be zero length. Any errors will be treated as fatal if
 * |fatal| is set. Returns 1 on success  0 on failure.
 */
int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
                             const unsigned char *label, size_t labellen,
                             const unsigned char *data, size_t datalen,
                             unsigned char *out, size_t outlen, int fatal)
{
#ifdef CHARSET_EBCDIC
    static const unsigned char label_prefix[] = { 0x74, 0x6C, 0x73, 0x31, 0x33, 0x20, 0x00 };
#else
    static const unsigned char label_prefix[] = "tls13 ";
#endif
    EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
    int ret;
    size_t hkdflabellen;
    size_t hashlen;
    /*
     * 2 bytes for length of derived secret + 1 byte for length of combined
     * prefix and label + bytes for the label itself + 1 byte length of hash
     * + bytes for the hash itself
     */
    unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t)
                            + (sizeof(label_prefix) - 1) + TLS13_MAX_LABEL_LEN
                            + 1 + EVP_MAX_MD_SIZE];
    WPACKET pkt;

    if (pctx == NULL)
        return 0;

    if (labellen > TLS13_MAX_LABEL_LEN) {
        if (fatal) {
            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
                     ERR_R_INTERNAL_ERROR);
        } else {
            /*
             * Probably we have been called from SSL_export_keying_material(),
             * or SSL_export_keying_material_early().
             */
            SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
        }
        EVP_PKEY_CTX_free(pctx);
        return 0;
    }

    hashlen = EVP_MD_size(md);

    if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
            || !WPACKET_put_bytes_u16(&pkt, outlen)
            || !WPACKET_start_sub_packet_u8(&pkt)
            || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
            || !WPACKET_memcpy(&pkt, label, labellen)
            || !WPACKET_close(&pkt)
            || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
            || !WPACKET_get_total_written(&pkt, &hkdflabellen)
            || !WPACKET_finish(&pkt)) {
        EVP_PKEY_CTX_free(pctx);
        WPACKET_cleanup(&pkt);
        if (fatal)
            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
                     ERR_R_INTERNAL_ERROR);
        else
            SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
        return 0;
    }

    ret = EVP_PKEY_derive_init(pctx) <= 0
            || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
               <= 0
            || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
            || EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
            || EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
            || EVP_PKEY_derive(pctx, out, &outlen) <= 0;

    EVP_PKEY_CTX_free(pctx);

    if (ret != 0) {
        if (fatal)
            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
                     ERR_R_INTERNAL_ERROR);
        else
            SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
    }

    return ret == 0;
}

/*
 * Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
 * success  0 on failure.
 */
int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
                     unsigned char *key, size_t keylen)
{
#ifdef CHARSET_EBCDIC
  static const unsigned char keylabel[] ={ 0x6B, 0x65, 0x79, 0x00 };
#else
  static const unsigned char keylabel[] = "key";
#endif

    return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
                             NULL, 0, key, keylen, 1);
}

/*
 * Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
 * success  0 on failure.
 */
int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
                    unsigned char *iv, size_t ivlen)
{
#ifdef CHARSET_EBCDIC
  static const unsigned char ivlabel[] = { 0x69, 0x76, 0x00 };
#else
  static const unsigned char ivlabel[] = "iv";
#endif

    return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
                             NULL, 0, iv, ivlen, 1);
}

int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
                             const unsigned char *secret,
                             unsigned char *fin, size_t finlen)
{
#ifdef CHARSET_EBCDIC
  static const unsigned char finishedlabel[] = { 0x66, 0x69, 0x6E, 0x69, 0x73, 0x68, 0x65, 0x64, 0x00 };
#else
  static const unsigned char finishedlabel[] = "finished";
#endif

    return tls13_hkdf_expand(s, md, secret, finishedlabel,
                             sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1);
}

/*
 * Given the previous secret |prevsecret| and a new input secret |insecret| of
 * length |insecretlen|, generate a new secret and store it in the location
 * pointed to by |outsecret|. Returns 1 on success  0 on failure.
 */
int tls13_generate_secret(SSL *s, const EVP_MD *md,
                          const unsigned char *prevsecret,
                          const unsigned char *insecret,
                          size_t insecretlen,
                          unsigned char *outsecret)
{
    size_t mdlen, prevsecretlen;
    int mdleni;
    int ret;
    EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
#ifdef CHARSET_EBCDIC
    static const char derived_secret_label[] = { 0x64, 0x65, 0x72, 0x69, 0x76, 0x65, 0x64, 0x00 };
#else
    static const char derived_secret_label[] = "derived";
#endif
    unsigned char preextractsec[EVP_MAX_MD_SIZE];

    if (pctx == NULL) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
                 ERR_R_INTERNAL_ERROR);
        return 0;
    }

    mdleni = EVP_MD_size(md);
    /* Ensure cast to size_t is safe */
    if (!ossl_assert(mdleni >= 0)) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
                 ERR_R_INTERNAL_ERROR);
        return 0;
    }
    mdlen = (size_t)mdleni;

    if (insecret == NULL) {
        insecret = default_zeros;
        insecretlen = mdlen;
    }
    if (prevsecret == NULL) {
        prevsecret = default_zeros;
        prevsecretlen = 0;
    } else {
        EVP_MD_CTX *mctx = EVP_MD_CTX_new();
        unsigned char hash[EVP_MAX_MD_SIZE];

        /* The pre-extract derive step uses a hash of no messages */
        if (mctx == NULL
                || EVP_DigestInit_ex(mctx, md, NULL) <= 0
                || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
                     ERR_R_INTERNAL_ERROR);
            EVP_MD_CTX_free(mctx);
            EVP_PKEY_CTX_free(pctx);
            return 0;
        }
        EVP_MD_CTX_free(mctx);

        /* Generate the pre-extract secret */
        if (!tls13_hkdf_expand(s, md, prevsecret,
                               (unsigned char *)derived_secret_label,
                               sizeof(derived_secret_label) - 1, hash, mdlen,
                               preextractsec, mdlen, 1)) {
            /* SSLfatal() already called */
            EVP_PKEY_CTX_free(pctx);
            return 0;
        }

        prevsecret = preextractsec;
        prevsecretlen = mdlen;
    }

    ret = EVP_PKEY_derive_init(pctx) <= 0
            || EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY)
               <= 0
            || EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
            || EVP_PKEY_CTX_set1_hkdf_key(pctx, insecret, insecretlen) <= 0
            || EVP_PKEY_CTX_set1_hkdf_salt(pctx, prevsecret, prevsecretlen)
               <= 0
            || EVP_PKEY_derive(pctx, outsecret, &mdlen)
               <= 0;

    if (ret != 0)
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
                 ERR_R_INTERNAL_ERROR);

    EVP_PKEY_CTX_free(pctx);
    if (prevsecret == preextractsec)
        OPENSSL_cleanse(preextractsec, mdlen);
    return ret == 0;
}

/*
 * Given an input secret |insecret| of length |insecretlen| generate the
 * handshake secret. This requires the early secret to already have been
 * generated. Returns 1 on success  0 on failure.
 */
int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
                                size_t insecretlen)
{
    /* Calls SSLfatal() if required */
    return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
                                 insecret, insecretlen,
                                 (unsigned char *)&s->handshake_secret);
}

/*
 * Given the handshake secret |prev| of length |prevlen| generate the master
 * secret and store its length in |*secret_size|. Returns 1 on success  0 on
 * failure.
 */
int tls13_generate_master_secret(SSL *s, unsigned char *out,
                                 unsigned char *prev, size_t prevlen,
                                 size_t *secret_size)
{
    const EVP_MD *md = ssl_handshake_md(s);

    *secret_size = EVP_MD_size(md);
    /* Calls SSLfatal() if required */
    return tls13_generate_secret(s, md, prev, NULL, 0, out);
}

/*
 * Generates the mac for the Finished message. Returns the length of the MAC or
 * 0 on error.
 */
size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
                             unsigned char *out)
{
    const EVP_MD *md = ssl_handshake_md(s);
    unsigned char hash[EVP_MAX_MD_SIZE];
    size_t hashlen, ret = 0;
    EVP_PKEY *key = NULL;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();

    if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
        /* SSLfatal() already called */
        goto err;
    }

    if (str == s->method->ssl3_enc->server_finished_label) {
        key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
                                           s->server_finished_secret, hashlen);
    } else if (SSL_IS_FIRST_HANDSHAKE(s)) {
        key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
                                           s->client_finished_secret, hashlen);
    } else {
        unsigned char finsecret[EVP_MAX_MD_SIZE];

        if (!tls13_derive_finishedkey(s, ssl_handshake_md(s),
                                      s->client_app_traffic_secret,
                                      finsecret, hashlen))
            goto err;

        key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, finsecret,
                                           hashlen);
        OPENSSL_cleanse(finsecret, sizeof(finsecret));
    }

    if (key == NULL
            || ctx == NULL
            || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
            || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
            || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
                 ERR_R_INTERNAL_ERROR);
        goto err;
    }

    ret = hashlen;
 err:
    EVP_PKEY_free(key);
    EVP_MD_CTX_free(ctx);
    return ret;
}

/*
 * There isn't really a key block in TLSv1.3, but we still need this function
 * for initialising the cipher and hash. Returns 1 on success or 0 on failure.
 */
int tls13_setup_key_block(SSL *s)
{
    const EVP_CIPHER *c;
    const EVP_MD *hash;

    s->session->cipher = s->s3->tmp.new_cipher;
    if (!ssl_cipher_get_evp(s->session, &c, &hash, NULL, NULL, NULL, 0)) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
                 SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
        return 0;
    }

    s->s3->tmp.new_sym_enc = c;
    s->s3->tmp.new_hash = hash;

    return 1;
}

static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
                                    const EVP_CIPHER *ciph,
                                    const unsigned char *insecret,
                                    const unsigned char *hash,
                                    const unsigned char *label,
                                    size_t labellen, unsigned char *secret,
                                    unsigned char *iv, EVP_CIPHER_CTX *ciph_ctx)
{
    unsigned char key[EVP_MAX_KEY_LENGTH];
    size_t ivlen, keylen, taglen;
    int hashleni = EVP_MD_size(md);
    size_t hashlen;

    /* Ensure cast to size_t is safe */
    if (!ossl_assert(hashleni >= 0)) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
                 ERR_R_EVP_LIB);
        goto err;
    }
    hashlen = (size_t)hashleni;

    if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
                           secret, hashlen, 1)) {
        /* SSLfatal() already called */
        goto err;
    }

    /* TODO(size_t): convert me */
    keylen = EVP_CIPHER_key_length(ciph);
    if (EVP_CIPHER_mode(ciph) == EVP_CIPH_CCM_MODE) {
        uint32_t algenc;

        ivlen = EVP_CCM_TLS_IV_LEN;
        if (s->s3->tmp.new_cipher != NULL) {
            algenc = s->s3->tmp.new_cipher->algorithm_enc;
        } else if (s->session->cipher != NULL) {
            /* We've not selected a cipher yet - we must be doing early data */
            algenc = s->session->cipher->algorithm_enc;
        } else if (s->psksession != NULL && s->psksession->cipher != NULL) {
            /* We must be doing early data with out-of-band PSK */
            algenc = s->psksession->cipher->algorithm_enc;
        } else {
            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
                     ERR_R_EVP_LIB);
            goto err;
        }
        if (algenc & (SSL_AES128CCM8 | SSL_AES256CCM8))
            taglen = EVP_CCM8_TLS_TAG_LEN;
         else
            taglen = EVP_CCM_TLS_TAG_LEN;
    } else {
        ivlen = EVP_CIPHER_iv_length(ciph);
        taglen = 0;
    }

    if (!tls13_derive_key(s, md, secret, key, keylen)
            || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
        /* SSLfatal() already called */
        goto err;
    }

    if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
        || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
        || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
                                                taglen, NULL))
        || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
                 ERR_R_EVP_LIB);
        goto err;
    }

    return 1;
 err:
    OPENSSL_cleanse(key, sizeof(key));
    return 0;
}

int tls13_change_cipher_state(SSL *s, int which)
{
#ifdef CHARSET_EBCDIC
  static const unsigned char client_early_traffic[]       = {0x63, 0x20, 0x65, 0x20,       /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
  static const unsigned char client_handshake_traffic[]   = {0x63, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
  static const unsigned char client_application_traffic[] = {0x63, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
  static const unsigned char server_handshake_traffic[]   = {0x73, 0x20, 0x68, 0x73, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
  static const unsigned char server_application_traffic[] = {0x73, 0x20, 0x61, 0x70, 0x20, /*traffic*/0x74, 0x72, 0x61, 0x66, 0x66, 0x69, 0x63, 0x00};
  static const unsigned char exporter_master_secret[] = {0x65, 0x78, 0x70, 0x20,                    /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
  static const unsigned char resumption_master_secret[] = {0x72, 0x65, 0x73, 0x20,                  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
  static const unsigned char early_exporter_master_secret[] = {0x65, 0x20, 0x65, 0x78, 0x70, 0x20,  /* master*/  0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x00};
#else
    static const unsigned char client_early_traffic[] = "c e traffic";
    static const unsigned char client_handshake_traffic[] = "c hs traffic";
    static const unsigned char client_application_traffic[] = "c ap traffic";
    static const unsigned char server_handshake_traffic[] = "s hs traffic";
    static const unsigned char server_application_traffic[] = "s ap traffic";
    static const unsigned char exporter_master_secret[] = "exp master";
    static const unsigned char resumption_master_secret[] = "res master";
    static const unsigned char early_exporter_master_secret[] = "e exp master";
#endif
    unsigned char *iv;
    unsigned char secret[EVP_MAX_MD_SIZE];
    unsigned char hashval[EVP_MAX_MD_SIZE];
    unsigned char *hash = hashval;
    unsigned char *insecret;
    unsigned char *finsecret = NULL;
    const char *log_label = NULL;
    EVP_CIPHER_CTX *ciph_ctx;
    size_t finsecretlen = 0;
    const unsigned char *label;
    size_t labellen, hashlen = 0;
    int ret = 0;
    const EVP_MD *md = NULL;
    const EVP_CIPHER *cipher = NULL;

    if (which & SSL3_CC_READ) {
        if (s->enc_read_ctx != NULL) {
            EVP_CIPHER_CTX_reset(s->enc_read_ctx);
        } else {
            s->enc_read_ctx = EVP_CIPHER_CTX_new();
            if (s->enc_read_ctx == NULL) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
                goto err;
            }
        }
        ciph_ctx = s->enc_read_ctx;
        iv = s->read_iv;

        RECORD_LAYER_reset_read_sequence(&s->rlayer);
    } else {
        s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
        if (s->enc_write_ctx != NULL) {
            EVP_CIPHER_CTX_reset(s->enc_write_ctx);
        } else {
            s->enc_write_ctx = EVP_CIPHER_CTX_new();
            if (s->enc_write_ctx == NULL) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
                goto err;
            }
        }
        ciph_ctx = s->enc_write_ctx;
        iv = s->write_iv;

        RECORD_LAYER_reset_write_sequence(&s->rlayer);
    }

    if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
            || ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
        if (which & SSL3_CC_EARLY) {
            EVP_MD_CTX *mdctx = NULL;
            long handlen;
            void *hdata;
            unsigned int hashlenui;
            const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);

            insecret = s->early_secret;
            label = client_early_traffic;
            labellen = sizeof(client_early_traffic) - 1;
            log_label = CLIENT_EARLY_LABEL;

            handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
            if (handlen <= 0) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE,
                         SSL_R_BAD_HANDSHAKE_LENGTH);
                goto err;
            }

            if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
                    && s->max_early_data > 0
                    && s->session->ext.max_early_data == 0) {
                /*
                 * If we are attempting to send early data, and we've decided to
                 * actually do it but max_early_data in s->session is 0 then we
                 * must be using an external PSK.
                 */
                if (!ossl_assert(s->psksession != NULL
                        && s->max_early_data ==
                           s->psksession->ext.max_early_data)) {
                    SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                             SSL_F_TLS13_CHANGE_CIPHER_STATE,
                             ERR_R_INTERNAL_ERROR);
                    goto err;
                }
                sslcipher = SSL_SESSION_get0_cipher(s->psksession);
            }
            if (sslcipher == NULL) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
                goto err;
            }

            /*
             * We need to calculate the handshake digest using the digest from
             * the session. We haven't yet selected our ciphersuite so we can't
             * use ssl_handshake_md().
             */
            mdctx = EVP_MD_CTX_new();
            if (mdctx == NULL) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
                goto err;
            }
            cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
            md = ssl_md(sslcipher->algorithm2);
            if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
                    || !EVP_DigestUpdate(mdctx, hdata, handlen)
                    || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
                EVP_MD_CTX_free(mdctx);
                goto err;
            }
            hashlen = hashlenui;
            EVP_MD_CTX_free(mdctx);

            if (!tls13_hkdf_expand(s, md, insecret,
                                   early_exporter_master_secret,
                                   sizeof(early_exporter_master_secret) - 1,
                                   hashval, hashlen,
                                   s->early_exporter_master_secret, hashlen,
                                   1)) {
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
                goto err;
            }

            if (!ssl_log_secret(s, EARLY_EXPORTER_SECRET_LABEL,
                                s->early_exporter_master_secret, hashlen)) {
                /* SSLfatal() already called */
                goto err;
            }
        } else if (which & SSL3_CC_HANDSHAKE) {
            insecret = s->handshake_secret;
            finsecret = s->client_finished_secret;
            finsecretlen = EVP_MD_size(ssl_handshake_md(s));
            label = client_handshake_traffic;
            labellen = sizeof(client_handshake_traffic) - 1;
            log_label = CLIENT_HANDSHAKE_LABEL;
            /*
             * The handshake hash used for the server read/client write handshake
             * traffic secret is the same as the hash for the server
             * write/client read handshake traffic secret. However, if we
             * processed early data then we delay changing the server
             * read/client write cipher state until later, and the handshake
             * hashes have moved on. Therefore we use the value saved earlier
             * when we did the server write/client read change cipher state.
             */
            hash = s->handshake_traffic_hash;
        } else {
            insecret = s->master_secret;
            label = client_application_traffic;
            labellen = sizeof(client_application_traffic) - 1;
            log_label = CLIENT_APPLICATION_LABEL;
            /*
             * For this we only use the handshake hashes up until the server
             * Finished hash. We do not include the client's Finished, which is
             * what ssl_handshake_hash() would give us. Instead we use the
             * previously saved value.
             */
            hash = s->server_finished_hash;
        }
    } else {
        /* Early data never applies to client-read/server-write */
        if (which & SSL3_CC_HANDSHAKE) {
            insecret = s->handshake_secret;
            finsecret = s->server_finished_secret;
            finsecretlen = EVP_MD_size(ssl_handshake_md(s));
            label = server_handshake_traffic;
            labellen = sizeof(server_handshake_traffic) - 1;
            log_label = SERVER_HANDSHAKE_LABEL;
        } else {
            insecret = s->master_secret;
            label = server_application_traffic;
            labellen = sizeof(server_application_traffic) - 1;
            log_label = SERVER_APPLICATION_LABEL;
        }
    }

    if (!(which & SSL3_CC_EARLY)) {
        md = ssl_handshake_md(s);
        cipher = s->s3->tmp.new_sym_enc;
        if (!ssl3_digest_cached_records(s, 1)
                || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
            /* SSLfatal() already called */;
            goto err;
        }
    }

    /*
     * Save the hash of handshakes up to now for use when we calculate the
     * client application traffic secret
     */
    if (label == server_application_traffic)
        memcpy(s->server_finished_hash, hashval, hashlen);

    if (label == server_handshake_traffic)
        memcpy(s->handshake_traffic_hash, hashval, hashlen);

    if (label == client_application_traffic) {
        /*
         * We also create the resumption master secret, but this time use the
         * hash for the whole handshake including the Client Finished
         */
        if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
                               resumption_master_secret,
                               sizeof(resumption_master_secret) - 1,
                               hashval, hashlen, s->resumption_master_secret,
                               hashlen, 1)) {
            /* SSLfatal() already called */
            goto err;
        }
    }

    if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
                                  insecret, hash, label, labellen, secret, iv,
                                  ciph_ctx)) {
        /* SSLfatal() already called */
        goto err;
    }

    if (label == server_application_traffic) {
        memcpy(s->server_app_traffic_secret, secret, hashlen);
        /* Now we create the exporter master secret */
        if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
                               exporter_master_secret,
                               sizeof(exporter_master_secret) - 1,
                               hash, hashlen, s->exporter_master_secret,
                               hashlen, 1)) {
            /* SSLfatal() already called */
            goto err;
        }

        if (!ssl_log_secret(s, EXPORTER_SECRET_LABEL, s->exporter_master_secret,
                            hashlen)) {
            /* SSLfatal() already called */
            goto err;
        }
    } else if (label == client_application_traffic)
        memcpy(s->client_app_traffic_secret, secret, hashlen);

    if (!ssl_log_secret(s, log_label, secret, hashlen)) {
        /* SSLfatal() already called */
        goto err;
    }

    if (finsecret != NULL
            && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
                                         finsecret, finsecretlen)) {
        /* SSLfatal() already called */
        goto err;
    }

    if (!s->server && label == client_early_traffic)
        s->statem.enc_write_state = ENC_WRITE_STATE_WRITE_PLAIN_ALERTS;
    else
        s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
    ret = 1;
 err:
    OPENSSL_cleanse(secret, sizeof(secret));
    return ret;
}

int tls13_update_key(SSL *s, int sending)
{
#ifdef CHARSET_EBCDIC
  static const unsigned char application_traffic[] = { 0x74, 0x72 ,0x61 ,0x66 ,0x66 ,0x69 ,0x63 ,0x20 ,0x75 ,0x70 ,0x64, 0x00};
#else
  static const unsigned char application_traffic[] = "traffic upd";
#endif
    const EVP_MD *md = ssl_handshake_md(s);
    size_t hashlen = EVP_MD_size(md);
    unsigned char *insecret, *iv;
    unsigned char secret[EVP_MAX_MD_SIZE];
    EVP_CIPHER_CTX *ciph_ctx;
    int ret = 0;

    if (s->server == sending)
        insecret = s->server_app_traffic_secret;
    else
        insecret = s->client_app_traffic_secret;

    if (sending) {
        s->statem.enc_write_state = ENC_WRITE_STATE_INVALID;
        iv = s->write_iv;
        ciph_ctx = s->enc_write_ctx;
        RECORD_LAYER_reset_write_sequence(&s->rlayer);
    } else {
        iv = s->read_iv;
        ciph_ctx = s->enc_read_ctx;
        RECORD_LAYER_reset_read_sequence(&s->rlayer);
    }

    if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
                                  s->s3->tmp.new_sym_enc, insecret, NULL,
                                  application_traffic,
                                  sizeof(application_traffic) - 1, secret, iv,
                                  ciph_ctx)) {
        /* SSLfatal() already called */
        goto err;
    }

    memcpy(insecret, secret, hashlen);

    s->statem.enc_write_state = ENC_WRITE_STATE_VALID;
    ret = 1;
 err:
    OPENSSL_cleanse(secret, sizeof(secret));
    return ret;
}

int tls13_alert_code(int code)
{
    /* There are 2 additional alerts in TLSv1.3 compared to TLSv1.2 */
    if (code == SSL_AD_MISSING_EXTENSION || code == SSL_AD_CERTIFICATE_REQUIRED)
        return code;

    return tls1_alert_code(code);
}

int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
                                 const char *label, size_t llen,
                                 const unsigned char *context,
                                 size_t contextlen, int use_context)
{
    unsigned char exportsecret[EVP_MAX_MD_SIZE];
#ifdef CHARSET_EBCDIC
    static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
#else
    static const unsigned char exporterlabel[] = "exporter";
#endif
    unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
    const EVP_MD *md = ssl_handshake_md(s);
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
    unsigned int hashsize, datalen;
    int ret = 0;

    if (ctx == NULL || !ossl_statem_export_allowed(s))
        goto err;

    if (!use_context)
        contextlen = 0;

    if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
            || EVP_DigestUpdate(ctx, context, contextlen) <= 0
            || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
            || EVP_DigestInit_ex(ctx, md, NULL) <= 0
            || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
            || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
                                  (const unsigned char *)label, llen,
                                  data, datalen, exportsecret, hashsize, 0)
            || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
                                  sizeof(exporterlabel) - 1, hash, hashsize,
                                  out, olen, 0))
        goto err;

    ret = 1;
 err:
    EVP_MD_CTX_free(ctx);
    return ret;
}

int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
                                       const char *label, size_t llen,
                                       const unsigned char *context,
                                       size_t contextlen)
{
#ifdef CHARSET_EBCDIC
  static const unsigned char exporterlabel[] = {0x65, 0x78, 0x70, 0x6F, 0x72, 0x74, 0x65, 0x72, 0x00};
#else
  static const unsigned char exporterlabel[] = "exporter";
#endif
    unsigned char exportsecret[EVP_MAX_MD_SIZE];
    unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
    const EVP_MD *md;
    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
    unsigned int hashsize, datalen;
    int ret = 0;
    const SSL_CIPHER *sslcipher;

    if (ctx == NULL || !ossl_statem_export_early_allowed(s))
        goto err;

    if (!s->server && s->max_early_data > 0
            && s->session->ext.max_early_data == 0)
        sslcipher = SSL_SESSION_get0_cipher(s->psksession);
    else
        sslcipher = SSL_SESSION_get0_cipher(s->session);

    md = ssl_md(sslcipher->algorithm2);

    /*
     * Calculate the hash value and store it in |data|. The reason why
     * the empty string is used is that the definition of TLS-Exporter
     * is like so:
     *
     * TLS-Exporter(label, context_value, key_length) =
     *     HKDF-Expand-Label(Derive-Secret(Secret, label, ""),
     *                       "exporter", Hash(context_value), key_length)
     *
     * Derive-Secret(Secret, Label, Messages) =
     *       HKDF-Expand-Label(Secret, Label,
     *                         Transcript-Hash(Messages), Hash.length)
     *
     * Here Transcript-Hash is the cipher suite hash algorithm.
     */
    if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
            || EVP_DigestUpdate(ctx, context, contextlen) <= 0
            || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
            || EVP_DigestInit_ex(ctx, md, NULL) <= 0
            || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
            || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret,
                                  (const unsigned char *)label, llen,
                                  data, datalen, exportsecret, hashsize, 0)
            || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
                                  sizeof(exporterlabel) - 1, hash, hashsize,
                                  out, olen, 0))
        goto err;

    ret = 1;
 err:
    EVP_MD_CTX_free(ctx);
    return ret;
}