summaryrefslogtreecommitdiffstats
path: root/CryptoPkg/Library/BaseCryptLib/Pk/CryptX509.c
blob: 9b5579e71a7550fedbc2f18ebf546e322ba6cd4e (plain)
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
/** @file
  X.509 Certificate Handler Wrapper Implementation over OpenSSL.

Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "InternalCryptLib.h"
#include <openssl/x509.h>
#include <openssl/rsa.h>

/**
  Construct a X509 object from DER-encoded certificate data.

  If Cert is NULL, then return FALSE.
  If SingleX509Cert is NULL, then return FALSE.

  @param[in]  Cert            Pointer to the DER-encoded certificate data.
  @param[in]  CertSize        The size of certificate data in bytes.
  @param[out] SingleX509Cert  The generated X509 object.

  @retval     TRUE            The X509 object generation succeeded.
  @retval     FALSE           The operation failed.

**/
BOOLEAN
EFIAPI
X509ConstructCertificate (
  IN   CONST UINT8  *Cert,
  IN   UINTN        CertSize,
  OUT  UINT8        **SingleX509Cert
  )
{
  X509         *X509Cert;
  CONST UINT8  *Temp;

  //
  // Check input parameters.
  //
  if (Cert == NULL || SingleX509Cert == NULL || CertSize > INT_MAX) {
    return FALSE;
  }

  //
  // Read DER-encoded X509 Certificate and Construct X509 object.
  //
  Temp     = Cert;
  X509Cert = d2i_X509 (NULL, &Temp, (long) CertSize);
  if (X509Cert == NULL) {
    return FALSE;
  }

  *SingleX509Cert = (UINT8 *) X509Cert;

  return TRUE;
}

/**
  Construct a X509 stack object from a list of DER-encoded certificate data.

  If X509Stack is NULL, then return FALSE.

  @param[in, out]  X509Stack  On input, pointer to an existing or NULL X509 stack object.
                              On output, pointer to the X509 stack object with new
                              inserted X509 certificate.
  @param           ...        A list of DER-encoded single certificate data followed
                              by certificate size. A NULL terminates the list. The
                              pairs are the arguments to X509ConstructCertificate().

  @retval     TRUE            The X509 stack construction succeeded.
  @retval     FALSE           The construction operation failed.

**/
BOOLEAN
EFIAPI
X509ConstructCertificateStack (
  IN OUT  UINT8  **X509Stack,
  ...
  )
{
  UINT8           *Cert;
  UINTN           CertSize;
  X509            *X509Cert;
  STACK_OF(X509)  *CertStack;
  BOOLEAN         Status;
  VA_LIST         Args;
  UINTN           Index;

  //
  // Check input parameters.
  //
  if (X509Stack == NULL) {
    return FALSE;
  }

  Status = FALSE;

  //
  // Initialize X509 stack object.
  //
  CertStack = (STACK_OF(X509) *) (*X509Stack);
  if (CertStack == NULL) {
    CertStack = sk_X509_new_null ();
    if (CertStack == NULL) {
      return Status;
    }
  }

  VA_START (Args, X509Stack);

  for (Index = 0; ; Index++) {
    //
    // If Cert is NULL, then it is the end of the list.
    //
    Cert = VA_ARG (Args, UINT8 *);
    if (Cert == NULL) {
      break;
    }

    CertSize = VA_ARG (Args, UINTN);
    if (CertSize == 0) {
      break;
    }

    //
    // Construct X509 Object from the given DER-encoded certificate data.
    //
    X509Cert = NULL;
    Status = X509ConstructCertificate (
               (CONST UINT8 *) Cert,
               CertSize,
               (UINT8 **) &X509Cert
               );
    if (!Status) {
      if (X509Cert != NULL) {
        X509_free (X509Cert);
      }
      break;
    }

    //
    // Insert the new X509 object into X509 stack object.
    //
    sk_X509_push (CertStack, X509Cert);
  }

  VA_END (Args);

  if (!Status) {
    sk_X509_pop_free (CertStack, X509_free);
  } else {
    *X509Stack = (UINT8 *) CertStack;
  }

  return Status;
}

/**
  Release the specified X509 object.

  If X509Cert is NULL, then return FALSE.

  @param[in]  X509Cert  Pointer to the X509 object to be released.

**/
VOID
EFIAPI
X509Free (
  IN  VOID  *X509Cert
  )
{
  //
  // Check input parameters.
  //
  if (X509Cert == NULL) {
    return;
  }

  //
  // Free OpenSSL X509 object.
  //
  X509_free ((X509 *) X509Cert);
}

/**
  Release the specified X509 stack object.

  If X509Stack is NULL, then return FALSE.

  @param[in]  X509Stack  Pointer to the X509 stack object to be released.

**/
VOID
EFIAPI
X509StackFree (
  IN  VOID  *X509Stack
  )
{
  //
  // Check input parameters.
  //
  if (X509Stack == NULL) {
    return;
  }

  //
  // Free OpenSSL X509 stack object.
  //
  sk_X509_pop_free ((STACK_OF(X509) *) X509Stack, X509_free);
}

/**
  Retrieve the subject bytes from one X.509 certificate.

  @param[in]      Cert         Pointer to the DER-encoded X509 certificate.
  @param[in]      CertSize     Size of the X509 certificate in bytes.
  @param[out]     CertSubject  Pointer to the retrieved certificate subject bytes.
  @param[in, out] SubjectSize  The size in bytes of the CertSubject buffer on input,
                               and the size of buffer returned CertSubject on output.

  If Cert is NULL, then return FALSE.
  If SubjectSize is NULL, then return FALSE.

  @retval  TRUE   The certificate subject retrieved successfully.
  @retval  FALSE  Invalid certificate, or the SubjectSize is too small for the result.
                  The SubjectSize will be updated with the required size.

**/
BOOLEAN
EFIAPI
X509GetSubjectName (
  IN      CONST UINT8  *Cert,
  IN      UINTN        CertSize,
  OUT     UINT8        *CertSubject,
  IN OUT  UINTN        *SubjectSize
  )
{
  BOOLEAN    Status;
  X509       *X509Cert;
  X509_NAME  *X509Name;
  UINTN      X509NameSize;

  //
  // Check input parameters.
  //
  if (Cert == NULL || SubjectSize == NULL) {
    return FALSE;
  }

  X509Cert = NULL;

  //
  // Read DER-encoded X509 Certificate and Construct X509 object.
  //
  Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
  if ((X509Cert == NULL) || (!Status)) {
    Status = FALSE;
    goto _Exit;
  }

  Status = FALSE;

  //
  // Retrieve subject name from certificate object.
  //
  X509Name = X509_get_subject_name (X509Cert);
  if (X509Name == NULL) {
    goto _Exit;
  }

  X509NameSize = i2d_X509_NAME(X509Name, NULL);
  if (*SubjectSize < X509NameSize) {
    *SubjectSize = X509NameSize;
    goto _Exit;
  }
  *SubjectSize = X509NameSize;
  if (CertSubject != NULL) {
    i2d_X509_NAME(X509Name, &CertSubject);
    Status = TRUE;
  }

_Exit:
  //
  // Release Resources.
  //
  if (X509Cert != NULL) {
    X509_free (X509Cert);
  }

  return Status;
}

/**
  Retrieve a string from one X.509 certificate base on the Request_NID.

  @param[in]      Cert             Pointer to the DER-encoded X509 certificate.
  @param[in]      CertSize         Size of the X509 certificate in bytes.
  @param[in]      Request_NID      NID of string to obtain
  @param[out]     CommonName       Buffer to contain the retrieved certificate common
                                   name string (UTF8). At most CommonNameSize bytes will be
                                   written and the string will be null terminated. May be
                                   NULL in order to determine the size buffer needed.
  @param[in,out]  CommonNameSize   The size in bytes of the CommonName buffer on input,
                                   and the size of buffer returned CommonName on output.
                                   If CommonName is NULL then the amount of space needed
                                   in buffer (including the final null) is returned.

  @retval RETURN_SUCCESS           The certificate CommonName retrieved successfully.
  @retval RETURN_INVALID_PARAMETER If Cert is NULL.
                                   If CommonNameSize is NULL.
                                   If CommonName is not NULL and *CommonNameSize is 0.
                                   If Certificate is invalid.
  @retval RETURN_NOT_FOUND         If no NID Name entry exists.
  @retval RETURN_BUFFER_TOO_SMALL  If the CommonName is NULL. The required buffer size
                                   (including the final null) is returned in the
                                   CommonNameSize parameter.
  @retval RETURN_UNSUPPORTED       The operation is not supported.

**/
STATIC
RETURN_STATUS
InternalX509GetNIDName (
  IN      CONST UINT8   *Cert,
  IN      UINTN         CertSize,
  IN      INT32         Request_NID,
  OUT     CHAR8         *CommonName,  OPTIONAL
  IN OUT  UINTN         *CommonNameSize
  )
{
  RETURN_STATUS    ReturnStatus;
  BOOLEAN          Status;
  X509             *X509Cert;
  X509_NAME        *X509Name;
  INT32            Index;
  INTN             Length;
  X509_NAME_ENTRY  *Entry;
  ASN1_STRING      *EntryData;
  UINT8            *UTF8Name;

  ReturnStatus = RETURN_INVALID_PARAMETER;
  UTF8Name     = NULL;

  //
  // Check input parameters.
  //
  if ((Cert == NULL) || (CertSize > INT_MAX) || (CommonNameSize == NULL)) {
    return ReturnStatus;
  }
  if ((CommonName != NULL) && (*CommonNameSize == 0)) {
    return ReturnStatus;
  }

  X509Cert = NULL;
  //
  // Read DER-encoded X509 Certificate and Construct X509 object.
  //
  Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
  if ((X509Cert == NULL) || (!Status)) {
    //
    // Invalid X.509 Certificate
    //
    goto _Exit;
  }

  Status = FALSE;

  //
  // Retrieve subject name from certificate object.
  //
  X509Name = X509_get_subject_name (X509Cert);
  if (X509Name == NULL) {
    //
    // Fail to retrieve subject name content
    //
    goto _Exit;
  }

  //
  // Retrive the string from X.509 Subject base on the Request_NID
  //
  Index = X509_NAME_get_index_by_NID (X509Name, Request_NID, -1);
  if (Index < 0) {
    //
    // No Request_NID name entry exists in X509_NAME object
    //
    *CommonNameSize = 0;
    ReturnStatus    = RETURN_NOT_FOUND;
    goto _Exit;
  }

  Entry = X509_NAME_get_entry (X509Name, Index);
  if (Entry == NULL) {
    //
    // Fail to retrieve name entry data
    //
    *CommonNameSize = 0;
    ReturnStatus    = RETURN_NOT_FOUND;
    goto _Exit;
  }

  EntryData = X509_NAME_ENTRY_get_data (Entry);

  Length = ASN1_STRING_to_UTF8 (&UTF8Name, EntryData);
  if (Length < 0) {
    //
    // Fail to convert the Name string
    //
    *CommonNameSize = 0;
    ReturnStatus    = RETURN_INVALID_PARAMETER;
    goto _Exit;
  }

  if (CommonName == NULL) {
    *CommonNameSize = Length + 1;
    ReturnStatus = RETURN_BUFFER_TOO_SMALL;
  } else {
    *CommonNameSize = MIN ((UINTN)Length, *CommonNameSize - 1) + 1;
    CopyMem (CommonName, UTF8Name, *CommonNameSize - 1);
    CommonName[*CommonNameSize - 1] = '\0';
    ReturnStatus = RETURN_SUCCESS;
  }

_Exit:
  //
  // Release Resources.
  //
  if (X509Cert != NULL) {
    X509_free (X509Cert);
  }
  if (UTF8Name != NULL) {
    OPENSSL_free (UTF8Name);
  }

  return ReturnStatus;
}

/**
  Retrieve the common name (CN) string from one X.509 certificate.

  @param[in]      Cert             Pointer to the DER-encoded X509 certificate.
  @param[in]      CertSize         Size of the X509 certificate in bytes.
  @param[out]     CommonName       Buffer to contain the retrieved certificate common
                                   name string. At most CommonNameSize bytes will be
                                   written and the string will be null terminated. May be
                                   NULL in order to determine the size buffer needed.
  @param[in,out]  CommonNameSize   The size in bytes of the CommonName buffer on input,
                                   and the size of buffer returned CommonName on output.
                                   If CommonName is NULL then the amount of space needed
                                   in buffer (including the final null) is returned.

  @retval RETURN_SUCCESS           The certificate CommonName retrieved successfully.
  @retval RETURN_INVALID_PARAMETER If Cert is NULL.
                                   If CommonNameSize is NULL.
                                   If CommonName is not NULL and *CommonNameSize is 0.
                                   If Certificate is invalid.
  @retval RETURN_NOT_FOUND         If no CommonName entry exists.
  @retval RETURN_BUFFER_TOO_SMALL  If the CommonName is NULL. The required buffer size
                                   (including the final null) is returned in the
                                   CommonNameSize parameter.
  @retval RETURN_UNSUPPORTED       The operation is not supported.

**/
RETURN_STATUS
EFIAPI
X509GetCommonName (
  IN      CONST UINT8  *Cert,
  IN      UINTN        CertSize,
  OUT     CHAR8        *CommonName,  OPTIONAL
  IN OUT  UINTN        *CommonNameSize
  )
{
  return InternalX509GetNIDName (Cert, CertSize, NID_commonName, CommonName, CommonNameSize);
}

/**
  Retrieve the organization name (O) string from one X.509 certificate.

  @param[in]      Cert             Pointer to the DER-encoded X509 certificate.
  @param[in]      CertSize         Size of the X509 certificate in bytes.
  @param[out]     NameBuffer       Buffer to contain the retrieved certificate organization
                                   name string. At most NameBufferSize bytes will be
                                   written and the string will be null terminated. May be
                                   NULL in order to determine the size buffer needed.
  @param[in,out]  NameBufferSize   The size in bytes of the Name buffer on input,
                                   and the size of buffer returned Name on output.
                                   If NameBuffer is NULL then the amount of space needed
                                   in buffer (including the final null) is returned.

  @retval RETURN_SUCCESS           The certificate Organization Name retrieved successfully.
  @retval RETURN_INVALID_PARAMETER If Cert is NULL.
                                   If NameBufferSize is NULL.
                                   If NameBuffer is not NULL and *CommonNameSize is 0.
                                   If Certificate is invalid.
  @retval RETURN_NOT_FOUND         If no Organization Name entry exists.
  @retval RETURN_BUFFER_TOO_SMALL  If the NameBuffer is NULL. The required buffer size
                                   (including the final null) is returned in the
                                   CommonNameSize parameter.
  @retval RETURN_UNSUPPORTED       The operation is not supported.

**/
RETURN_STATUS
EFIAPI
X509GetOrganizationName (
  IN      CONST UINT8   *Cert,
  IN      UINTN         CertSize,
  OUT     CHAR8         *NameBuffer,  OPTIONAL
  IN OUT  UINTN         *NameBufferSize
  )
{
  return InternalX509GetNIDName (Cert, CertSize, NID_organizationName, NameBuffer, NameBufferSize);
}

/**
  Retrieve the RSA Public Key from one DER-encoded X509 certificate.

  @param[in]  Cert         Pointer to the DER-encoded X509 certificate.
  @param[in]  CertSize     Size of the X509 certificate in bytes.
  @param[out] RsaContext   Pointer to new-generated RSA context which contain the retrieved
                           RSA public key component. Use RsaFree() function to free the
                           resource.

  If Cert is NULL, then return FALSE.
  If RsaContext is NULL, then return FALSE.

  @retval  TRUE   RSA Public Key was retrieved successfully.
  @retval  FALSE  Fail to retrieve RSA public key from X509 certificate.

**/
BOOLEAN
EFIAPI
RsaGetPublicKeyFromX509 (
  IN   CONST UINT8  *Cert,
  IN   UINTN        CertSize,
  OUT  VOID         **RsaContext
  )
{
  BOOLEAN   Status;
  EVP_PKEY  *Pkey;
  X509      *X509Cert;

  //
  // Check input parameters.
  //
  if (Cert == NULL || RsaContext == NULL) {
    return FALSE;
  }

  Pkey     = NULL;
  X509Cert = NULL;

  //
  // Read DER-encoded X509 Certificate and Construct X509 object.
  //
  Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
  if ((X509Cert == NULL) || (!Status)) {
    Status = FALSE;
    goto _Exit;
  }

  Status = FALSE;

  //
  // Retrieve and check EVP_PKEY data from X509 Certificate.
  //
  Pkey = X509_get_pubkey (X509Cert);
  if ((Pkey == NULL) || (EVP_PKEY_id (Pkey) != EVP_PKEY_RSA)) {
    goto _Exit;
  }

  //
  // Duplicate RSA Context from the retrieved EVP_PKEY.
  //
  if ((*RsaContext = RSAPublicKey_dup (EVP_PKEY_get0_RSA (Pkey))) != NULL) {
    Status = TRUE;
  }

_Exit:
  //
  // Release Resources.
  //
  if (X509Cert != NULL) {
    X509_free (X509Cert);
  }

  if (Pkey != NULL) {
    EVP_PKEY_free (Pkey);
  }

  return Status;
}

/**
  Verify one X509 certificate was issued by the trusted CA.

  @param[in]      Cert         Pointer to the DER-encoded X509 certificate to be verified.
  @param[in]      CertSize     Size of the X509 certificate in bytes.
  @param[in]      CACert       Pointer to the DER-encoded trusted CA certificate.
  @param[in]      CACertSize   Size of the CA Certificate in bytes.

  If Cert is NULL, then return FALSE.
  If CACert is NULL, then return FALSE.

  @retval  TRUE   The certificate was issued by the trusted CA.
  @retval  FALSE  Invalid certificate or the certificate was not issued by the given
                  trusted CA.

**/
BOOLEAN
EFIAPI
X509VerifyCert (
  IN  CONST UINT8  *Cert,
  IN  UINTN        CertSize,
  IN  CONST UINT8  *CACert,
  IN  UINTN        CACertSize
  )
{
  BOOLEAN         Status;
  X509            *X509Cert;
  X509            *X509CACert;
  X509_STORE      *CertStore;
  X509_STORE_CTX  *CertCtx;

  //
  // Check input parameters.
  //
  if (Cert == NULL || CACert == NULL) {
    return FALSE;
  }

  Status     = FALSE;
  X509Cert   = NULL;
  X509CACert = NULL;
  CertStore  = NULL;
  CertCtx    = NULL;

  //
  // Register & Initialize necessary digest algorithms for certificate verification.
  //
  if (EVP_add_digest (EVP_md5 ()) == 0) {
    goto _Exit;
  }
  if (EVP_add_digest (EVP_sha1 ()) == 0) {
    goto _Exit;
  }
  if (EVP_add_digest (EVP_sha256 ()) == 0) {
    goto _Exit;
  }

  //
  // Read DER-encoded certificate to be verified and Construct X509 object.
  //
  Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
  if ((X509Cert == NULL) || (!Status)) {
    Status = FALSE;
    goto _Exit;
  }

  //
  // Read DER-encoded root certificate and Construct X509 object.
  //
  Status = X509ConstructCertificate (CACert, CACertSize, (UINT8 **) &X509CACert);
  if ((X509CACert == NULL) || (!Status)) {
    Status = FALSE;
    goto _Exit;
  }

  Status = FALSE;

  //
  // Set up X509 Store for trusted certificate.
  //
  CertStore = X509_STORE_new ();
  if (CertStore == NULL) {
    goto _Exit;
  }
  if (!(X509_STORE_add_cert (CertStore, X509CACert))) {
    goto _Exit;
  }

  //
  // Allow partial certificate chains, terminated by a non-self-signed but
  // still trusted intermediate certificate. Also disable time checks.
  //
  X509_STORE_set_flags (CertStore,
                        X509_V_FLAG_PARTIAL_CHAIN | X509_V_FLAG_NO_CHECK_TIME);

  //
  // Set up X509_STORE_CTX for the subsequent verification operation.
  //
  CertCtx = X509_STORE_CTX_new ();
  if (CertCtx == NULL) {
    goto _Exit;
  }
  if (!X509_STORE_CTX_init (CertCtx, CertStore, X509Cert, NULL)) {
    goto _Exit;
  }

  //
  // X509 Certificate Verification.
  //
  Status = (BOOLEAN) X509_verify_cert (CertCtx);
  X509_STORE_CTX_cleanup (CertCtx);

_Exit:
  //
  // Release Resources.
  //
  if (X509Cert != NULL) {
    X509_free (X509Cert);
  }

  if (X509CACert != NULL) {
    X509_free (X509CACert);
  }

  if (CertStore != NULL) {
    X509_STORE_free (CertStore);
  }

  X509_STORE_CTX_free (CertCtx);

  return Status;
}

/**
  Retrieve the TBSCertificate from one given X.509 certificate.

  @param[in]      Cert         Pointer to the given DER-encoded X509 certificate.
  @param[in]      CertSize     Size of the X509 certificate in bytes.
  @param[out]     TBSCert      DER-Encoded To-Be-Signed certificate.
  @param[out]     TBSCertSize  Size of the TBS certificate in bytes.

  If Cert is NULL, then return FALSE.
  If TBSCert is NULL, then return FALSE.
  If TBSCertSize is NULL, then return FALSE.

  @retval  TRUE   The TBSCertificate was retrieved successfully.
  @retval  FALSE  Invalid X.509 certificate.

**/
BOOLEAN
EFIAPI
X509GetTBSCert (
  IN  CONST UINT8  *Cert,
  IN  UINTN        CertSize,
  OUT UINT8        **TBSCert,
  OUT UINTN        *TBSCertSize
  )
{
  CONST UINT8  *Temp;
  UINT32       Asn1Tag;
  UINT32       ObjClass;
  UINTN        Length;

  //
  // Check input parameters.
  //
  if ((Cert == NULL) || (TBSCert == NULL) ||
      (TBSCertSize == NULL) || (CertSize > INT_MAX)) {
    return FALSE;
  }

  //
  // An X.509 Certificate is: (defined in RFC3280)
  //   Certificate  ::=  SEQUENCE  {
  //     tbsCertificate       TBSCertificate,
  //     signatureAlgorithm   AlgorithmIdentifier,
  //     signature            BIT STRING }
  //
  // and
  //
  //  TBSCertificate  ::=  SEQUENCE  {
  //    version         [0]  Version DEFAULT v1,
  //    ...
  //    }
  //
  // So we can just ASN1-parse the x.509 DER-encoded data. If we strip
  // the first SEQUENCE, the second SEQUENCE is the TBSCertificate.
  //
  Temp   = Cert;
  Length = 0;
  ASN1_get_object (&Temp, (long *)&Length, (int *)&Asn1Tag, (int *)&ObjClass, (long)CertSize);

  if (Asn1Tag != V_ASN1_SEQUENCE) {
    return FALSE;
  }

  *TBSCert = (UINT8 *)Temp;

  ASN1_get_object (&Temp, (long *)&Length, (int *)&Asn1Tag, (int *)&ObjClass, (long)Length);
  //
  // Verify the parsed TBSCertificate is one correct SEQUENCE data.
  //
  if (Asn1Tag != V_ASN1_SEQUENCE) {
    return FALSE;
  }

  *TBSCertSize = Length + (Temp - *TBSCert);

  return TRUE;
}