CryptoPkg/Library/BaseCryptLib/Pk/CryptX509.c

   1 /** @file
   2   X.509 Certificate Handler Wrapper Implementation over OpenSSL.
   3
   4 Copyright (c) 2010 - 2020, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "InternalCryptLib.h"
  10 #include <openssl/x509.h>
  11 #include <openssl/rsa.h>
  12
  13 /**
  14   Construct a X509 object from DER-encoded certificate data.
  15
  16   If Cert is NULL, then return FALSE.
  17   If SingleX509Cert is NULL, then return FALSE.
  18
  19   @param[in]  Cert            Pointer to the DER-encoded certificate data.
  20   @param[in]  CertSize        The size of certificate data in bytes.
  21   @param[out] SingleX509Cert  The generated X509 object.
  22
  23   @retval     TRUE            The X509 object generation succeeded.
  24   @retval     FALSE           The operation failed.
  25
  26 **/
  27 BOOLEAN
  28 EFIAPI
  29 X509ConstructCertificate (
  30   IN   CONST UINT8  *Cert,
  31   IN   UINTN        CertSize,
  32   OUT  UINT8        **SingleX509Cert
  33   )
  34 {
  35   X509         *X509Cert;
  36   CONST UINT8  *Temp;
  37
  38   //
  39   // Check input parameters.
  40   //
  41   if (Cert == NULL || SingleX509Cert == NULL || CertSize > INT_MAX) {
  42     return FALSE;
  43   }
  44
  45   //
  46   // Read DER-encoded X509 Certificate and Construct X509 object.
  47   //
  48   Temp     = Cert;
  49   X509Cert = d2i_X509 (NULL, &Temp, (long) CertSize);
  50   if (X509Cert == NULL) {
  51     return FALSE;
  52   }
  53
  54   *SingleX509Cert = (UINT8 *) X509Cert;
  55
  56   return TRUE;
  57 }
  58
  59 /**
  60   Construct a X509 stack object from a list of DER-encoded certificate data.
  61
  62   If X509Stack is NULL, then return FALSE.
  63   If this interface is not supported, then return FALSE.
  64
  65   @param[in, out]  X509Stack  On input, pointer to an existing or NULL X509 stack object.
  66                               On output, pointer to the X509 stack object with new
  67                               inserted X509 certificate.
  68   @param[in]       Args       VA_LIST marker for the variable argument list.
  69                               A list of DER-encoded single certificate data followed
  70                               by certificate size. A NULL terminates the list. The
  71                               pairs are the arguments to X509ConstructCertificate().
  72
  73   @retval     TRUE            The X509 stack construction succeeded.
  74   @retval     FALSE           The construction operation failed.
  75   @retval     FALSE           This interface is not supported.
  76
  77 **/
  78 BOOLEAN
  79 EFIAPI
  80 X509ConstructCertificateStackV (
  81   IN OUT  UINT8    **X509Stack,
  82   IN      VA_LIST  Args
  83   )
  84 {
  85   UINT8           *Cert;
  86   UINTN           CertSize;
  87   X509            *X509Cert;
  88   STACK_OF(X509)  *CertStack;
  89   BOOLEAN         Status;
  90   UINTN           Index;
  91
  92   //
  93   // Check input parameters.
  94   //
  95   if (X509Stack == NULL) {
  96     return FALSE;
  97   }
  98
  99   Status = FALSE;
 100
 101   //
 102   // Initialize X509 stack object.
 103   //
 104   CertStack = (STACK_OF(X509) *) (*X509Stack);
 105   if (CertStack == NULL) {
 106     CertStack = sk_X509_new_null ();
 107     if (CertStack == NULL) {
 108       return Status;
 109     }
 110   }
 111
 112   for (Index = 0; ; Index++) {
 113     //
 114     // If Cert is NULL, then it is the end of the list.
 115     //
 116     Cert = VA_ARG (Args, UINT8 *);
 117     if (Cert == NULL) {
 118       break;
 119     }
 120
 121     CertSize = VA_ARG (Args, UINTN);
 122     if (CertSize == 0) {
 123       break;
 124     }
 125
 126     //
 127     // Construct X509 Object from the given DER-encoded certificate data.
 128     //
 129     X509Cert = NULL;
 130     Status = X509ConstructCertificate (
 131                (CONST UINT8 *) Cert,
 132                CertSize,
 133                (UINT8 **) &X509Cert
 134                );
 135     if (!Status) {
 136       if (X509Cert != NULL) {
 137         X509_free (X509Cert);
 138       }
 139       break;
 140     }
 141
 142     //
 143     // Insert the new X509 object into X509 stack object.
 144     //
 145     sk_X509_push (CertStack, X509Cert);
 146   }
 147
 148   if (!Status) {
 149     sk_X509_pop_free (CertStack, X509_free);
 150   } else {
 151     *X509Stack = (UINT8 *) CertStack;
 152   }
 153
 154   return Status;
 155 }
 156
 157 /**
 158   Construct a X509 stack object from a list of DER-encoded certificate data.
 159
 160   If X509Stack is NULL, then return FALSE.
 161
 162   @param[in, out]  X509Stack  On input, pointer to an existing or NULL X509 stack object.
 163                               On output, pointer to the X509 stack object with new
 164                               inserted X509 certificate.
 165   @param           ...        A list of DER-encoded single certificate data followed
 166                               by certificate size. A NULL terminates the list. The
 167                               pairs are the arguments to X509ConstructCertificate().
 168
 169   @retval     TRUE            The X509 stack construction succeeded.
 170   @retval     FALSE           The construction operation failed.
 171
 172 **/
 173 BOOLEAN
 174 EFIAPI
 175 X509ConstructCertificateStack (
 176   IN OUT  UINT8  **X509Stack,
 177   ...
 178   )
 179 {
 180   VA_LIST  Args;
 181   BOOLEAN  Result;
 182
 183   VA_START (Args, X509Stack);
 184   Result = X509ConstructCertificateStackV (X509Stack, Args);
 185   VA_END (Args);
 186   return Result;
 187 }
 188
 189 /**
 190   Release the specified X509 object.
 191
 192   If X509Cert is NULL, then return FALSE.
 193
 194   @param[in]  X509Cert  Pointer to the X509 object to be released.
 195
 196 **/
 197 VOID
 198 EFIAPI
 199 X509Free (
 200   IN  VOID  *X509Cert
 201   )
 202 {
 203   //
 204   // Check input parameters.
 205   //
 206   if (X509Cert == NULL) {
 207     return;
 208   }
 209
 210   //
 211   // Free OpenSSL X509 object.
 212   //
 213   X509_free ((X509 *) X509Cert);
 214 }
 215
 216 /**
 217   Release the specified X509 stack object.
 218
 219   If X509Stack is NULL, then return FALSE.
 220
 221   @param[in]  X509Stack  Pointer to the X509 stack object to be released.
 222
 223 **/
 224 VOID
 225 EFIAPI
 226 X509StackFree (
 227   IN  VOID  *X509Stack
 228   )
 229 {
 230   //
 231   // Check input parameters.
 232   //
 233   if (X509Stack == NULL) {
 234     return;
 235   }
 236
 237   //
 238   // Free OpenSSL X509 stack object.
 239   //
 240   sk_X509_pop_free ((STACK_OF(X509) *) X509Stack, X509_free);
 241 }
 242
 243 /**
 244   Retrieve the subject bytes from one X.509 certificate.
 245
 246   @param[in]      Cert         Pointer to the DER-encoded X509 certificate.
 247   @param[in]      CertSize     Size of the X509 certificate in bytes.
 248   @param[out]     CertSubject  Pointer to the retrieved certificate subject bytes.
 249   @param[in, out] SubjectSize  The size in bytes of the CertSubject buffer on input,
 250                                and the size of buffer returned CertSubject on output.
 251
 252   If Cert is NULL, then return FALSE.
 253   If SubjectSize is NULL, then return FALSE.
 254
 255   @retval  TRUE   The certificate subject retrieved successfully.
 256   @retval  FALSE  Invalid certificate, or the SubjectSize is too small for the result.
 257                   The SubjectSize will be updated with the required size.
 258
 259 **/
 260 BOOLEAN
 261 EFIAPI
 262 X509GetSubjectName (
 263   IN      CONST UINT8  *Cert,
 264   IN      UINTN        CertSize,
 265   OUT     UINT8        *CertSubject,
 266   IN OUT  UINTN        *SubjectSize
 267   )
 268 {
 269   BOOLEAN    Status;
 270   X509       *X509Cert;
 271   X509_NAME  *X509Name;
 272   UINTN      X509NameSize;
 273
 274   //
 275   // Check input parameters.
 276   //
 277   if (Cert == NULL || SubjectSize == NULL) {
 278     return FALSE;
 279   }
 280
 281   X509Cert = NULL;
 282
 283   //
 284   // Read DER-encoded X509 Certificate and Construct X509 object.
 285   //
 286   Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
 287   if ((X509Cert == NULL) || (!Status)) {
 288     Status = FALSE;
 289     goto _Exit;
 290   }
 291
 292   Status = FALSE;
 293
 294   //
 295   // Retrieve subject name from certificate object.
 296   //
 297   X509Name = X509_get_subject_name (X509Cert);
 298   if (X509Name == NULL) {
 299     goto _Exit;
 300   }
 301
 302   X509NameSize = i2d_X509_NAME(X509Name, NULL);
 303   if (*SubjectSize < X509NameSize) {
 304     *SubjectSize = X509NameSize;
 305     goto _Exit;
 306   }
 307   *SubjectSize = X509NameSize;
 308   if (CertSubject != NULL) {
 309     i2d_X509_NAME(X509Name, &CertSubject);
 310     Status = TRUE;
 311   }
 312
 313 _Exit:
 314   //
 315   // Release Resources.
 316   //
 317   if (X509Cert != NULL) {
 318     X509_free (X509Cert);
 319   }
 320
 321   return Status;
 322 }
 323
 324 /**
 325   Retrieve a string from one X.509 certificate base on the Request_NID.
 326
 327   @param[in]      Cert             Pointer to the DER-encoded X509 certificate.
 328   @param[in]      CertSize         Size of the X509 certificate in bytes.
 329   @param[in]      Request_NID      NID of string to obtain
 330   @param[out]     CommonName       Buffer to contain the retrieved certificate common
 331                                    name string (UTF8). At most CommonNameSize bytes will be
 332                                    written and the string will be null terminated. May be
 333                                    NULL in order to determine the size buffer needed.
 334   @param[in,out]  CommonNameSize   The size in bytes of the CommonName buffer on input,
 335                                    and the size of buffer returned CommonName on output.
 336                                    If CommonName is NULL then the amount of space needed
 337                                    in buffer (including the final null) is returned.
 338
 339   @retval RETURN_SUCCESS           The certificate CommonName retrieved successfully.
 340   @retval RETURN_INVALID_PARAMETER If Cert is NULL.
 341                                    If CommonNameSize is NULL.
 342                                    If CommonName is not NULL and *CommonNameSize is 0.
 343                                    If Certificate is invalid.
 344   @retval RETURN_NOT_FOUND         If no NID Name entry exists.
 345   @retval RETURN_BUFFER_TOO_SMALL  If the CommonName is NULL. The required buffer size
 346                                    (including the final null) is returned in the
 347                                    CommonNameSize parameter.
 348   @retval RETURN_UNSUPPORTED       The operation is not supported.
 349
 350 **/
 351 STATIC
 352 RETURN_STATUS
 353 InternalX509GetNIDName (
 354   IN      CONST UINT8   *Cert,
 355   IN      UINTN         CertSize,
 356   IN      INT32         Request_NID,
 357   OUT     CHAR8         *CommonName,  OPTIONAL
 358   IN OUT  UINTN         *CommonNameSize
 359   )
 360 {
 361   RETURN_STATUS    ReturnStatus;
 362   BOOLEAN          Status;
 363   X509             *X509Cert;
 364   X509_NAME        *X509Name;
 365   INT32            Index;
 366   INTN             Length;
 367   X509_NAME_ENTRY  *Entry;
 368   ASN1_STRING      *EntryData;
 369   UINT8            *UTF8Name;
 370
 371   ReturnStatus = RETURN_INVALID_PARAMETER;
 372   UTF8Name     = NULL;
 373
 374   //
 375   // Check input parameters.
 376   //
 377   if ((Cert == NULL) || (CertSize > INT_MAX) || (CommonNameSize == NULL)) {
 378     return ReturnStatus;
 379   }
 380   if ((CommonName != NULL) && (*CommonNameSize == 0)) {
 381     return ReturnStatus;
 382   }
 383
 384   X509Cert = NULL;
 385   //
 386   // Read DER-encoded X509 Certificate and Construct X509 object.
 387   //
 388   Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
 389   if ((X509Cert == NULL) || (!Status)) {
 390     //
 391     // Invalid X.509 Certificate
 392     //
 393     goto _Exit;
 394   }
 395
 396   Status = FALSE;
 397
 398   //
 399   // Retrieve subject name from certificate object.
 400   //
 401   X509Name = X509_get_subject_name (X509Cert);
 402   if (X509Name == NULL) {
 403     //
 404     // Fail to retrieve subject name content
 405     //
 406     goto _Exit;
 407   }
 408
 409   //
 410   // Retrive the string from X.509 Subject base on the Request_NID
 411   //
 412   Index = X509_NAME_get_index_by_NID (X509Name, Request_NID, -1);
 413   if (Index < 0) {
 414     //
 415     // No Request_NID name entry exists in X509_NAME object
 416     //
 417     *CommonNameSize = 0;
 418     ReturnStatus    = RETURN_NOT_FOUND;
 419     goto _Exit;
 420   }
 421
 422   Entry = X509_NAME_get_entry (X509Name, Index);
 423   if (Entry == NULL) {
 424     //
 425     // Fail to retrieve name entry data
 426     //
 427     *CommonNameSize = 0;
 428     ReturnStatus    = RETURN_NOT_FOUND;
 429     goto _Exit;
 430   }
 431
 432   EntryData = X509_NAME_ENTRY_get_data (Entry);
 433
 434   Length = ASN1_STRING_to_UTF8 (&UTF8Name, EntryData);
 435   if (Length < 0) {
 436     //
 437     // Fail to convert the Name string
 438     //
 439     *CommonNameSize = 0;
 440     ReturnStatus    = RETURN_INVALID_PARAMETER;
 441     goto _Exit;
 442   }
 443
 444   if (CommonName == NULL) {
 445     *CommonNameSize = Length + 1;
 446     ReturnStatus = RETURN_BUFFER_TOO_SMALL;
 447   } else {
 448     *CommonNameSize = MIN ((UINTN)Length, *CommonNameSize - 1) + 1;
 449     CopyMem (CommonName, UTF8Name, *CommonNameSize - 1);
 450     CommonName[*CommonNameSize - 1] = '\0';
 451     ReturnStatus = RETURN_SUCCESS;
 452   }
 453
 454 _Exit:
 455   //
 456   // Release Resources.
 457   //
 458   if (X509Cert != NULL) {
 459     X509_free (X509Cert);
 460   }
 461   if (UTF8Name != NULL) {
 462     OPENSSL_free (UTF8Name);
 463   }
 464
 465   return ReturnStatus;
 466 }
 467
 468 /**
 469   Retrieve the common name (CN) string from one X.509 certificate.
 470
 471   @param[in]      Cert             Pointer to the DER-encoded X509 certificate.
 472   @param[in]      CertSize         Size of the X509 certificate in bytes.
 473   @param[out]     CommonName       Buffer to contain the retrieved certificate common
 474                                    name string. At most CommonNameSize bytes will be
 475                                    written and the string will be null terminated. May be
 476                                    NULL in order to determine the size buffer needed.
 477   @param[in,out]  CommonNameSize   The size in bytes of the CommonName buffer on input,
 478                                    and the size of buffer returned CommonName on output.
 479                                    If CommonName is NULL then the amount of space needed
 480                                    in buffer (including the final null) is returned.
 481
 482   @retval RETURN_SUCCESS           The certificate CommonName retrieved successfully.
 483   @retval RETURN_INVALID_PARAMETER If Cert is NULL.
 484                                    If CommonNameSize is NULL.
 485                                    If CommonName is not NULL and *CommonNameSize is 0.
 486                                    If Certificate is invalid.
 487   @retval RETURN_NOT_FOUND         If no CommonName entry exists.
 488   @retval RETURN_BUFFER_TOO_SMALL  If the CommonName is NULL. The required buffer size
 489                                    (including the final null) is returned in the
 490                                    CommonNameSize parameter.
 491   @retval RETURN_UNSUPPORTED       The operation is not supported.
 492
 493 **/
 494 RETURN_STATUS
 495 EFIAPI
 496 X509GetCommonName (
 497   IN      CONST UINT8  *Cert,
 498   IN      UINTN        CertSize,
 499   OUT     CHAR8        *CommonName,  OPTIONAL
 500   IN OUT  UINTN        *CommonNameSize
 501   )
 502 {
 503   return InternalX509GetNIDName (Cert, CertSize, NID_commonName, CommonName, CommonNameSize);
 504 }
 505
 506 /**
 507   Retrieve the organization name (O) string from one X.509 certificate.
 508
 509   @param[in]      Cert             Pointer to the DER-encoded X509 certificate.
 510   @param[in]      CertSize         Size of the X509 certificate in bytes.
 511   @param[out]     NameBuffer       Buffer to contain the retrieved certificate organization
 512                                    name string. At most NameBufferSize bytes will be
 513                                    written and the string will be null terminated. May be
 514                                    NULL in order to determine the size buffer needed.
 515   @param[in,out]  NameBufferSize   The size in bytes of the Name buffer on input,
 516                                    and the size of buffer returned Name on output.
 517                                    If NameBuffer is NULL then the amount of space needed
 518                                    in buffer (including the final null) is returned.
 519
 520   @retval RETURN_SUCCESS           The certificate Organization Name retrieved successfully.
 521   @retval RETURN_INVALID_PARAMETER If Cert is NULL.
 522                                    If NameBufferSize is NULL.
 523                                    If NameBuffer is not NULL and *CommonNameSize is 0.
 524                                    If Certificate is invalid.
 525   @retval RETURN_NOT_FOUND         If no Organization Name entry exists.
 526   @retval RETURN_BUFFER_TOO_SMALL  If the NameBuffer is NULL. The required buffer size
 527                                    (including the final null) is returned in the
 528                                    CommonNameSize parameter.
 529   @retval RETURN_UNSUPPORTED       The operation is not supported.
 530
 531 **/
 532 RETURN_STATUS
 533 EFIAPI
 534 X509GetOrganizationName (
 535   IN      CONST UINT8   *Cert,
 536   IN      UINTN         CertSize,
 537   OUT     CHAR8         *NameBuffer,  OPTIONAL
 538   IN OUT  UINTN         *NameBufferSize
 539   )
 540 {
 541   return InternalX509GetNIDName (Cert, CertSize, NID_organizationName, NameBuffer, NameBufferSize);
 542 }
 543
 544 /**
 545   Retrieve the RSA Public Key from one DER-encoded X509 certificate.
 546
 547   @param[in]  Cert         Pointer to the DER-encoded X509 certificate.
 548   @param[in]  CertSize     Size of the X509 certificate in bytes.
 549   @param[out] RsaContext   Pointer to new-generated RSA context which contain the retrieved
 550                            RSA public key component. Use RsaFree() function to free the
 551                            resource.
 552
 553   If Cert is NULL, then return FALSE.
 554   If RsaContext is NULL, then return FALSE.
 555
 556   @retval  TRUE   RSA Public Key was retrieved successfully.
 557   @retval  FALSE  Fail to retrieve RSA public key from X509 certificate.
 558
 559 **/
 560 BOOLEAN
 561 EFIAPI
 562 RsaGetPublicKeyFromX509 (
 563   IN   CONST UINT8  *Cert,
 564   IN   UINTN        CertSize,
 565   OUT  VOID         **RsaContext
 566   )
 567 {
 568   BOOLEAN   Status;
 569   EVP_PKEY  *Pkey;
 570   X509      *X509Cert;
 571
 572   //
 573   // Check input parameters.
 574   //
 575   if (Cert == NULL || RsaContext == NULL) {
 576     return FALSE;
 577   }
 578
 579   Pkey     = NULL;
 580   X509Cert = NULL;
 581
 582   //
 583   // Read DER-encoded X509 Certificate and Construct X509 object.
 584   //
 585   Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
 586   if ((X509Cert == NULL) || (!Status)) {
 587     Status = FALSE;
 588     goto _Exit;
 589   }
 590
 591   Status = FALSE;
 592
 593   //
 594   // Retrieve and check EVP_PKEY data from X509 Certificate.
 595   //
 596   Pkey = X509_get_pubkey (X509Cert);
 597   if ((Pkey == NULL) || (EVP_PKEY_id (Pkey) != EVP_PKEY_RSA)) {
 598     goto _Exit;
 599   }
 600
 601   //
 602   // Duplicate RSA Context from the retrieved EVP_PKEY.
 603   //
 604   if ((*RsaContext = RSAPublicKey_dup (EVP_PKEY_get0_RSA (Pkey))) != NULL) {
 605     Status = TRUE;
 606   }
 607
 608 _Exit:
 609   //
 610   // Release Resources.
 611   //
 612   if (X509Cert != NULL) {
 613     X509_free (X509Cert);
 614   }
 615
 616   if (Pkey != NULL) {
 617     EVP_PKEY_free (Pkey);
 618   }
 619
 620   return Status;
 621 }
 622
 623 /**
 624   Verify one X509 certificate was issued by the trusted CA.
 625
 626   @param[in]      Cert         Pointer to the DER-encoded X509 certificate to be verified.
 627   @param[in]      CertSize     Size of the X509 certificate in bytes.
 628   @param[in]      CACert       Pointer to the DER-encoded trusted CA certificate.
 629   @param[in]      CACertSize   Size of the CA Certificate in bytes.
 630
 631   If Cert is NULL, then return FALSE.
 632   If CACert is NULL, then return FALSE.
 633
 634   @retval  TRUE   The certificate was issued by the trusted CA.
 635   @retval  FALSE  Invalid certificate or the certificate was not issued by the given
 636                   trusted CA.
 637
 638 **/
 639 BOOLEAN
 640 EFIAPI
 641 X509VerifyCert (
 642   IN  CONST UINT8  *Cert,
 643   IN  UINTN        CertSize,
 644   IN  CONST UINT8  *CACert,
 645   IN  UINTN        CACertSize
 646   )
 647 {
 648   BOOLEAN         Status;
 649   X509            *X509Cert;
 650   X509            *X509CACert;
 651   X509_STORE      *CertStore;
 652   X509_STORE_CTX  *CertCtx;
 653
 654   //
 655   // Check input parameters.
 656   //
 657   if (Cert == NULL || CACert == NULL) {
 658     return FALSE;
 659   }
 660
 661   Status     = FALSE;
 662   X509Cert   = NULL;
 663   X509CACert = NULL;
 664   CertStore  = NULL;
 665   CertCtx    = NULL;
 666
 667   //
 668   // Register & Initialize necessary digest algorithms for certificate verification.
 669   //
 670   if (EVP_add_digest (EVP_md5 ()) == 0) {
 671     goto _Exit;
 672   }
 673   if (EVP_add_digest (EVP_sha1 ()) == 0) {
 674     goto _Exit;
 675   }
 676   if (EVP_add_digest (EVP_sha256 ()) == 0) {
 677     goto _Exit;
 678   }
 679
 680   //
 681   // Read DER-encoded certificate to be verified and Construct X509 object.
 682   //
 683   Status = X509ConstructCertificate (Cert, CertSize, (UINT8 **) &X509Cert);
 684   if ((X509Cert == NULL) || (!Status)) {
 685     Status = FALSE;
 686     goto _Exit;
 687   }
 688
 689   //
 690   // Read DER-encoded root certificate and Construct X509 object.
 691   //
 692   Status = X509ConstructCertificate (CACert, CACertSize, (UINT8 **) &X509CACert);
 693   if ((X509CACert == NULL) || (!Status)) {
 694     Status = FALSE;
 695     goto _Exit;
 696   }
 697
 698   Status = FALSE;
 699
 700   //
 701   // Set up X509 Store for trusted certificate.
 702   //
 703   CertStore = X509_STORE_new ();
 704   if (CertStore == NULL) {
 705     goto _Exit;
 706   }
 707   if (!(X509_STORE_add_cert (CertStore, X509CACert))) {
 708     goto _Exit;
 709   }
 710
 711   //
 712   // Allow partial certificate chains, terminated by a non-self-signed but
 713   // still trusted intermediate certificate. Also disable time checks.
 714   //
 715   X509_STORE_set_flags (CertStore,
 716                         X509_V_FLAG_PARTIAL_CHAIN | X509_V_FLAG_NO_CHECK_TIME);
 717
 718   //
 719   // Set up X509_STORE_CTX for the subsequent verification operation.
 720   //
 721   CertCtx = X509_STORE_CTX_new ();
 722   if (CertCtx == NULL) {
 723     goto _Exit;
 724   }
 725   if (!X509_STORE_CTX_init (CertCtx, CertStore, X509Cert, NULL)) {
 726     goto _Exit;
 727   }
 728
 729   //
 730   // X509 Certificate Verification.
 731   //
 732   Status = (BOOLEAN) X509_verify_cert (CertCtx);
 733   X509_STORE_CTX_cleanup (CertCtx);
 734
 735 _Exit:
 736   //
 737   // Release Resources.
 738   //
 739   if (X509Cert != NULL) {
 740     X509_free (X509Cert);
 741   }
 742
 743   if (X509CACert != NULL) {
 744     X509_free (X509CACert);
 745   }
 746
 747   if (CertStore != NULL) {
 748     X509_STORE_free (CertStore);
 749   }
 750
 751   X509_STORE_CTX_free (CertCtx);
 752
 753   return Status;
 754 }
 755
 756 /**
 757   Retrieve the TBSCertificate from one given X.509 certificate.
 758
 759   @param[in]      Cert         Pointer to the given DER-encoded X509 certificate.
 760   @param[in]      CertSize     Size of the X509 certificate in bytes.
 761   @param[out]     TBSCert      DER-Encoded To-Be-Signed certificate.
 762   @param[out]     TBSCertSize  Size of the TBS certificate in bytes.
 763
 764   If Cert is NULL, then return FALSE.
 765   If TBSCert is NULL, then return FALSE.
 766   If TBSCertSize is NULL, then return FALSE.
 767
 768   @retval  TRUE   The TBSCertificate was retrieved successfully.
 769   @retval  FALSE  Invalid X.509 certificate.
 770
 771 **/
 772 BOOLEAN
 773 EFIAPI
 774 X509GetTBSCert (
 775   IN  CONST UINT8  *Cert,
 776   IN  UINTN        CertSize,
 777   OUT UINT8        **TBSCert,
 778   OUT UINTN        *TBSCertSize
 779   )
 780 {
 781   CONST UINT8  *Temp;
 782   UINT32       Asn1Tag;
 783   UINT32       ObjClass;
 784   UINTN        Length;
 785
 786   //
 787   // Check input parameters.
 788   //
 789   if ((Cert == NULL) || (TBSCert == NULL) ||
 790       (TBSCertSize == NULL) || (CertSize > INT_MAX)) {
 791     return FALSE;
 792   }
 793
 794   //
 795   // An X.509 Certificate is: (defined in RFC3280)
 796   //   Certificate  ::=  SEQUENCE  {
 797   //     tbsCertificate       TBSCertificate,
 798   //     signatureAlgorithm   AlgorithmIdentifier,
 799   //     signature            BIT STRING }
 800   //
 801   // and
 802   //
 803   //  TBSCertificate  ::=  SEQUENCE  {
 804   //    version         [0]  Version DEFAULT v1,
 805   //    ...
 806   //    }
 807   //
 808   // So we can just ASN1-parse the x.509 DER-encoded data. If we strip
 809   // the first SEQUENCE, the second SEQUENCE is the TBSCertificate.
 810   //
 811   Temp   = Cert;
 812   Length = 0;
 813   ASN1_get_object (&Temp, (long *)&Length, (int *)&Asn1Tag, (int *)&ObjClass, (long)CertSize);
 814
 815   if (Asn1Tag != V_ASN1_SEQUENCE) {
 816     return FALSE;
 817   }
 818
 819   *TBSCert = (UINT8 *)Temp;
 820
 821   ASN1_get_object (&Temp, (long *)&Length, (int *)&Asn1Tag, (int *)&ObjClass, (long)Length);
 822   //
 823   // Verify the parsed TBSCertificate is one correct SEQUENCE data.
 824   //
 825   if (Asn1Tag != V_ASN1_SEQUENCE) {
 826     return FALSE;
 827   }
 828
 829   *TBSCertSize = Length + (Temp - *TBSCert);
 830
 831   return TRUE;
 832 }