git.oblomov.eu Git - wine/blob - dlls/crypt32/cert.c

   1 /*
   2  * Copyright 2004-2006 Juan Lang
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  */
  19
  20 #include <assert.h>
  21 #include <stdarg.h>
  22 #include "windef.h"
  23 #include "winbase.h"
  24 #include "wincrypt.h"
  25 #include "wine/debug.h"
  26 #include "crypt32_private.h"
  27
  28 WINE_DEFAULT_DEBUG_CHANNEL(crypt);
  29
  30 PCRYPT_ATTRIBUTE WINAPI CertFindAttribute(LPCSTR pszObjId, DWORD cAttr,
  31  CRYPT_ATTRIBUTE rgAttr[])
  32 {
  33     PCRYPT_ATTRIBUTE ret = NULL;
  34     DWORD i;
  35
  36     TRACE("%s %ld %p\n", debugstr_a(pszObjId), cAttr, rgAttr);
  37
  38     if (!cAttr)
  39         return NULL;
  40     if (!pszObjId)
  41     {
  42         SetLastError(ERROR_INVALID_PARAMETER);
  43         return NULL;
  44     }
  45
  46     for (i = 0; !ret && i < cAttr; i++)
  47         if (rgAttr[i].pszObjId && !strcmp(pszObjId, rgAttr[i].pszObjId))
  48             ret = &rgAttr[i];
  49     return ret;
  50 }
  51
  52 PCERT_EXTENSION WINAPI CertFindExtension(LPCSTR pszObjId, DWORD cExtensions,
  53  CERT_EXTENSION rgExtensions[])
  54 {
  55     PCERT_EXTENSION ret = NULL;
  56     DWORD i;
  57
  58     TRACE("%s %ld %p\n", debugstr_a(pszObjId), cExtensions, rgExtensions);
  59
  60     if (!cExtensions)
  61         return NULL;
  62     if (!pszObjId)
  63     {
  64         SetLastError(ERROR_INVALID_PARAMETER);
  65         return NULL;
  66     }
  67
  68     for (i = 0; !ret && i < cExtensions; i++)
  69         if (rgExtensions[i].pszObjId && !strcmp(pszObjId,
  70          rgExtensions[i].pszObjId))
  71             ret = &rgExtensions[i];
  72     return ret;
  73 }
  74
  75 PCERT_RDN_ATTR WINAPI CertFindRDNAttr(LPCSTR pszObjId, PCERT_NAME_INFO pName)
  76 {
  77     PCERT_RDN_ATTR ret = NULL;
  78     DWORD i, j;
  79
  80     TRACE("%s %p\n", debugstr_a(pszObjId), pName);
  81
  82     if (!pszObjId)
  83     {
  84         SetLastError(ERROR_INVALID_PARAMETER);
  85         return NULL;
  86     }
  87
  88     for (i = 0; !ret && i < pName->cRDN; i++)
  89         for (j = 0; !ret && j < pName->rgRDN[i].cRDNAttr; j++)
  90             if (pName->rgRDN[i].rgRDNAttr[j].pszObjId && !strcmp(pszObjId,
  91              pName->rgRDN[i].rgRDNAttr[j].pszObjId))
  92                 ret = &pName->rgRDN[i].rgRDNAttr[j];
  93     return ret;
  94 }
  95
  96 LONG WINAPI CertVerifyTimeValidity(LPFILETIME pTimeToVerify,
  97  PCERT_INFO pCertInfo)
  98 {
  99     FILETIME fileTime;
 100     LONG ret;
 101
 102     if (!pTimeToVerify)
 103     {
 104         SYSTEMTIME sysTime;
 105
 106         GetSystemTime(&sysTime);
 107         SystemTimeToFileTime(&sysTime, &fileTime);
 108         pTimeToVerify = &fileTime;
 109     }
 110     if ((ret = CompareFileTime(pTimeToVerify, &pCertInfo->NotBefore)) >= 0)
 111     {
 112         ret = CompareFileTime(pTimeToVerify, &pCertInfo->NotAfter);
 113         if (ret < 0)
 114             ret = 0;
 115     }
 116     return ret;
 117 }
 118
 119 BOOL WINAPI CryptHashCertificate(HCRYPTPROV hCryptProv, ALG_ID Algid,
 120  DWORD dwFlags, const BYTE *pbEncoded, DWORD cbEncoded, BYTE *pbComputedHash,
 121  DWORD *pcbComputedHash)
 122 {
 123     BOOL ret = TRUE;
 124     HCRYPTHASH hHash = 0;
 125
 126     TRACE("(%ld, %d, %08lx, %p, %ld, %p, %p)\n", hCryptProv, Algid, dwFlags,
 127      pbEncoded, cbEncoded, pbComputedHash, pcbComputedHash);
 128
 129     if (!hCryptProv)
 130         hCryptProv = CRYPT_GetDefaultProvider();
 131     if (!Algid)
 132         Algid = CALG_SHA1;
 133     if (ret)
 134     {
 135         ret = CryptCreateHash(hCryptProv, Algid, 0, 0, &hHash);
 136         if (ret)
 137         {
 138             ret = CryptHashData(hHash, pbEncoded, cbEncoded, 0);
 139             if (ret)
 140                 ret = CryptGetHashParam(hHash, HP_HASHVAL, pbComputedHash,
 141                  pcbComputedHash, 0);
 142             CryptDestroyHash(hHash);
 143         }
 144     }
 145     return ret;
 146 }
 147
 148 BOOL WINAPI CryptSignCertificate(HCRYPTPROV hCryptProv, DWORD dwKeySpec,
 149  DWORD dwCertEncodingType, const BYTE *pbEncodedToBeSigned,
 150  DWORD cbEncodedToBeSigned, PCRYPT_ALGORITHM_IDENTIFIER pSignatureAlgorithm,
 151  const void *pvHashAuxInfo, BYTE *pbSignature, DWORD *pcbSignature)
 152 {
 153     BOOL ret;
 154     ALG_ID algID;
 155     HCRYPTHASH hHash;
 156
 157     TRACE("(%08lx, %ld, %ld, %p, %ld, %p, %p, %p, %p)\n", hCryptProv,
 158      dwKeySpec, dwCertEncodingType, pbEncodedToBeSigned, cbEncodedToBeSigned,
 159      pSignatureAlgorithm, pvHashAuxInfo, pbSignature, pcbSignature);
 160
 161     algID = CertOIDToAlgId(pSignatureAlgorithm->pszObjId);
 162     if (!algID)
 163     {
 164         SetLastError(NTE_BAD_ALGID);
 165         return FALSE;
 166     }
 167     if (!hCryptProv)
 168     {
 169         SetLastError(ERROR_INVALID_PARAMETER);
 170         return FALSE;
 171     }
 172
 173     ret = CryptCreateHash(hCryptProv, algID, 0, 0, &hHash);
 174     if (ret)
 175     {
 176         ret = CryptHashData(hHash, pbEncodedToBeSigned, cbEncodedToBeSigned, 0);
 177         if (ret)
 178             ret = CryptSignHashW(hHash, dwKeySpec, NULL, 0, pbSignature,
 179              pcbSignature);
 180         CryptDestroyHash(hHash);
 181     }
 182     return ret;
 183 }
 184
 185 BOOL WINAPI CryptVerifyCertificateSignature(HCRYPTPROV hCryptProv,
 186  DWORD dwCertEncodingType, const BYTE *pbEncoded, DWORD cbEncoded,
 187  PCERT_PUBLIC_KEY_INFO pPublicKey)
 188 {
 189     return CryptVerifyCertificateSignatureEx(hCryptProv, dwCertEncodingType,
 190      CRYPT_VERIFY_CERT_SIGN_SUBJECT_BLOB, (void *)pbEncoded,
 191      CRYPT_VERIFY_CERT_SIGN_ISSUER_PUBKEY, pPublicKey, 0, NULL);
 192 }
 193
 194 BOOL WINAPI CryptVerifyCertificateSignatureEx(HCRYPTPROV hCryptProv,
 195  DWORD dwCertEncodingType, DWORD dwSubjectType, void *pvSubject,
 196  DWORD dwIssuerType, void *pvIssuer, DWORD dwFlags, void *pvReserved)
 197 {
 198     BOOL ret = TRUE;
 199     CRYPT_DATA_BLOB subjectBlob;
 200
 201     TRACE("(%08lx, %ld, %ld, %p, %ld, %p, %08lx, %p)\n", hCryptProv,
 202      dwCertEncodingType, dwSubjectType, pvSubject, dwIssuerType, pvIssuer,
 203      dwFlags, pvReserved);
 204
 205     switch (dwSubjectType)
 206     {
 207     case CRYPT_VERIFY_CERT_SIGN_SUBJECT_BLOB:
 208     {
 209         PCRYPT_DATA_BLOB blob = (PCRYPT_DATA_BLOB)pvSubject;
 210
 211         subjectBlob.pbData = blob->pbData;
 212         subjectBlob.cbData = blob->cbData;
 213         break;
 214     }
 215     case CRYPT_VERIFY_CERT_SIGN_SUBJECT_CERT:
 216     {
 217         PCERT_CONTEXT context = (PCERT_CONTEXT)pvSubject;
 218
 219         subjectBlob.pbData = context->pbCertEncoded;
 220         subjectBlob.cbData = context->cbCertEncoded;
 221         break;
 222     }
 223     case CRYPT_VERIFY_CERT_SIGN_SUBJECT_CRL:
 224     {
 225         PCRL_CONTEXT context = (PCRL_CONTEXT)pvSubject;
 226
 227         subjectBlob.pbData = context->pbCrlEncoded;
 228         subjectBlob.cbData = context->cbCrlEncoded;
 229         break;
 230     }
 231     default:
 232         SetLastError(HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER));
 233         ret = FALSE;
 234     }
 235
 236     if (ret)
 237     {
 238         PCERT_SIGNED_CONTENT_INFO signedCert = NULL;
 239         DWORD size = 0;
 240
 241         ret = CryptDecodeObjectEx(dwCertEncodingType, X509_CERT,
 242          subjectBlob.pbData, subjectBlob.cbData,
 243          CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG, NULL,
 244          (BYTE *)&signedCert, &size);
 245         if (ret)
 246         {
 247             switch (dwIssuerType)
 248             {
 249             case CRYPT_VERIFY_CERT_SIGN_ISSUER_PUBKEY:
 250             {
 251                 PCERT_PUBLIC_KEY_INFO pubKeyInfo =
 252                  (PCERT_PUBLIC_KEY_INFO)pvIssuer;
 253                 ALG_ID algID = CertOIDToAlgId(pubKeyInfo->Algorithm.pszObjId);
 254
 255                 if (algID)
 256                 {
 257                     HCRYPTKEY key;
 258
 259                     ret = CryptImportPublicKeyInfoEx(hCryptProv,
 260                      dwCertEncodingType, pubKeyInfo, algID, 0, NULL, &key);
 261                     if (ret)
 262                     {
 263                         HCRYPTHASH hash;
 264
 265                         ret = CryptCreateHash(hCryptProv, algID, 0, 0, &hash);
 266                         if (ret)
 267                         {
 268                             ret = CryptHashData(hash,
 269                              signedCert->ToBeSigned.pbData,
 270                              signedCert->ToBeSigned.cbData, 0);
 271                             if (ret)
 272                             {
 273                                 ret = CryptVerifySignatureW(hash,
 274                                  signedCert->Signature.pbData,
 275                                  signedCert->Signature.cbData, key, NULL, 0);
 276                             }
 277                             CryptDestroyHash(hash);
 278                         }
 279                         CryptDestroyKey(key);
 280                     }
 281                 }
 282                 else
 283                 {
 284                     SetLastError(NTE_BAD_ALGID);
 285                     ret = FALSE;
 286                 }
 287                 break;
 288             }
 289             case CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT:
 290             case CRYPT_VERIFY_CERT_SIGN_ISSUER_CHAIN:
 291                 FIXME("issuer type %ld: stub\n", dwIssuerType);
 292                 ret = FALSE;
 293                 break;
 294             case CRYPT_VERIFY_CERT_SIGN_ISSUER_NULL:
 295                 if (pvIssuer)
 296                 {
 297                     SetLastError(HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER));
 298                     ret = FALSE;
 299                 }
 300                 else
 301                 {
 302                     FIXME("unimplemented for NULL signer\n");
 303                     SetLastError(HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER));
 304                     ret = FALSE;
 305                 }
 306                 break;
 307             default:
 308                 SetLastError(HRESULT_FROM_WIN32(ERROR_INVALID_PARAMETER));
 309                 ret = FALSE;
 310             }
 311             LocalFree(signedCert);
 312         }
 313     }
 314     return ret;
 315 }
 316
 317 BOOL WINAPI CryptVerifyMessageSignature(/*PCRYPT_VERIFY_MESSAGE_PARA*/ void* pVerifyPara,
 318           DWORD dwSignerIndex, const BYTE* pbSignedBlob, DWORD cbSignedBlob,
 319           BYTE* pbDecoded, DWORD* pcbDecoded, PCCERT_CONTEXT* ppSignerCert)
 320 {
 321     FIXME("stub: %p, %ld, %p, %ld, %p, %p, %p\n",
 322         pVerifyPara, dwSignerIndex, pbSignedBlob, cbSignedBlob,
 323         pbDecoded, pcbDecoded, ppSignerCert);
 324     return FALSE;
 325 }
 326
 327 BOOL WINAPI CertGetEnhancedKeyUsage(PCCERT_CONTEXT pCertContext, DWORD dwFlags,
 328  PCERT_ENHKEY_USAGE pUsage, DWORD *pcbUsage)
 329 {
 330     PCERT_ENHKEY_USAGE usage = NULL;
 331     DWORD bytesNeeded;
 332     BOOL ret = TRUE;
 333
 334     TRACE("(%p, %08lx, %p, %ld)\n", pCertContext, dwFlags, pUsage, *pcbUsage);
 335
 336     if (!pCertContext || !pcbUsage)
 337     {
 338         SetLastError(ERROR_INVALID_PARAMETER);
 339         return FALSE;
 340     }
 341
 342     if (!(dwFlags & CERT_FIND_EXT_ONLY_ENHKEY_USAGE_FLAG))
 343     {
 344         DWORD propSize = 0;
 345
 346         if (CertGetCertificateContextProperty(pCertContext,
 347          CERT_ENHKEY_USAGE_PROP_ID, NULL, &propSize))
 348         {
 349             LPBYTE buf = CryptMemAlloc(propSize);
 350
 351             if (buf)
 352             {
 353                 if (CertGetCertificateContextProperty(pCertContext,
 354                  CERT_ENHKEY_USAGE_PROP_ID, buf, &propSize))
 355                 {
 356                     ret = CryptDecodeObjectEx(pCertContext->dwCertEncodingType,
 357                      X509_ENHANCED_KEY_USAGE, buf, propSize,
 358                      CRYPT_ENCODE_ALLOC_FLAG, NULL, &usage, &bytesNeeded);
 359                 }
 360                 CryptMemFree(buf);
 361             }
 362         }
 363     }
 364     if (!usage && !(dwFlags & CERT_FIND_PROP_ONLY_ENHKEY_USAGE_FLAG))
 365     {
 366         PCERT_EXTENSION ext = CertFindExtension(szOID_ENHANCED_KEY_USAGE,
 367          pCertContext->pCertInfo->cExtension,
 368          pCertContext->pCertInfo->rgExtension);
 369
 370         if (ext)
 371         {
 372             ret = CryptDecodeObjectEx(pCertContext->dwCertEncodingType,
 373              X509_ENHANCED_KEY_USAGE, ext->Value.pbData, ext->Value.cbData,
 374              CRYPT_ENCODE_ALLOC_FLAG, NULL, &usage, &bytesNeeded);
 375         }
 376     }
 377     if (!usage)
 378     {
 379         /* If a particular location is specified, this should fail.  Otherwise
 380          * it should succeed with an empty usage.  (This is true on Win2k and
 381          * later, which we emulate.)
 382          */
 383         if (dwFlags)
 384         {
 385             SetLastError(CRYPT_E_NOT_FOUND);
 386             ret = FALSE;
 387         }
 388         else
 389             bytesNeeded = sizeof(CERT_ENHKEY_USAGE);
 390     }
 391
 392     if (ret)
 393     {
 394         if (!pUsage)
 395             *pcbUsage = bytesNeeded;
 396         else if (*pcbUsage < bytesNeeded)
 397         {
 398             SetLastError(ERROR_MORE_DATA);
 399             *pcbUsage = bytesNeeded;
 400             ret = FALSE;
 401         }
 402         else
 403         {
 404             *pcbUsage = bytesNeeded;
 405             if (usage)
 406             {
 407                 DWORD i;
 408                 LPSTR nextOID = (LPSTR)((LPBYTE)pUsage +
 409                  sizeof(CERT_ENHKEY_USAGE) +
 410                  usage->cUsageIdentifier * sizeof(LPSTR));
 411
 412                 pUsage->cUsageIdentifier = usage->cUsageIdentifier;
 413                 pUsage->rgpszUsageIdentifier = (LPSTR *)((LPBYTE)pUsage +
 414                  sizeof(CERT_ENHKEY_USAGE));
 415                 for (i = 0; i < usage->cUsageIdentifier; i++)
 416                 {
 417                     pUsage->rgpszUsageIdentifier[i] = nextOID;
 418                     strcpy(nextOID, usage->rgpszUsageIdentifier[i]);
 419                     nextOID += strlen(nextOID) + 1;
 420                 }
 421             }
 422             else
 423                 pUsage->cUsageIdentifier = 0;
 424         }
 425     }
 426     if (usage)
 427         LocalFree(usage);
 428     TRACE("returning %d\n", ret);
 429     return ret;
 430 }
 431
 432 BOOL WINAPI CertSetEnhancedKeyUsage(PCCERT_CONTEXT pCertContext,
 433  PCERT_ENHKEY_USAGE pUsage)
 434 {
 435     BOOL ret;
 436
 437     TRACE("(%p, %p)\n", pCertContext, pUsage);
 438
 439     if (pUsage)
 440     {
 441         CRYPT_DATA_BLOB blob = { 0, NULL };
 442
 443         ret = CryptEncodeObjectEx(X509_ASN_ENCODING, X509_ENHANCED_KEY_USAGE,
 444          pUsage, CRYPT_ENCODE_ALLOC_FLAG, NULL, &blob.pbData, &blob.cbData);
 445         if (ret)
 446         {
 447             ret = CertSetCertificateContextProperty(pCertContext,
 448              CERT_ENHKEY_USAGE_PROP_ID, 0, &blob);
 449             LocalFree(blob.pbData);
 450         }
 451     }
 452     else
 453         ret = CertSetCertificateContextProperty(pCertContext,
 454          CERT_ENHKEY_USAGE_PROP_ID, 0, NULL);
 455     return ret;
 456 }
 457
 458 BOOL WINAPI CertAddEnhancedKeyUsageIdentifier(PCCERT_CONTEXT pCertContext,
 459  LPCSTR pszUsageIdentifier)
 460 {
 461     BOOL ret;
 462     DWORD size;
 463
 464     TRACE("(%p, %s)\n", pCertContext, debugstr_a(pszUsageIdentifier));
 465
 466     if (CertGetEnhancedKeyUsage(pCertContext,
 467      CERT_FIND_PROP_ONLY_ENHKEY_USAGE_FLAG, NULL, &size))
 468     {
 469         PCERT_ENHKEY_USAGE usage = CryptMemAlloc(size);
 470
 471         if (usage)
 472         {
 473             ret = CertGetEnhancedKeyUsage(pCertContext,
 474              CERT_FIND_PROP_ONLY_ENHKEY_USAGE_FLAG, usage, &size);
 475             if (ret)
 476             {
 477                 PCERT_ENHKEY_USAGE newUsage = CryptMemAlloc(size +
 478                  sizeof(LPSTR) + strlen(pszUsageIdentifier) + 1);
 479
 480                 if (newUsage)
 481                 {
 482                     LPSTR nextOID;
 483                     DWORD i;
 484
 485                     newUsage->rgpszUsageIdentifier =
 486                      (LPSTR *)((LPBYTE)newUsage + sizeof(CERT_ENHKEY_USAGE));
 487                     nextOID = (LPSTR)((LPBYTE)newUsage->rgpszUsageIdentifier +
 488                      (usage->cUsageIdentifier + 1) * sizeof(LPSTR));
 489                     for (i = 0; i < usage->cUsageIdentifier; i++)
 490                     {
 491                         newUsage->rgpszUsageIdentifier[i] = nextOID;
 492                         strcpy(nextOID, usage->rgpszUsageIdentifier[i]);
 493                         nextOID += strlen(nextOID) + 1;
 494                     }
 495                     newUsage->rgpszUsageIdentifier[i] = nextOID;
 496                     strcpy(nextOID, pszUsageIdentifier);
 497                     newUsage->cUsageIdentifier = i + 1;
 498                     ret = CertSetEnhancedKeyUsage(pCertContext, newUsage);
 499                     CryptMemFree(newUsage);
 500                 }
 501             }
 502             CryptMemFree(usage);
 503         }
 504         else
 505             ret = FALSE;
 506     }
 507     else
 508     {
 509         PCERT_ENHKEY_USAGE usage = CryptMemAlloc(sizeof(CERT_ENHKEY_USAGE) +
 510          sizeof(LPSTR) + strlen(pszUsageIdentifier) + 1);
 511
 512         if (usage)
 513         {
 514             usage->rgpszUsageIdentifier =
 515              (LPSTR *)((LPBYTE)usage + sizeof(CERT_ENHKEY_USAGE));
 516             usage->rgpszUsageIdentifier[0] = (LPSTR)((LPBYTE)usage +
 517              sizeof(CERT_ENHKEY_USAGE) + sizeof(LPSTR));
 518             strcpy(usage->rgpszUsageIdentifier[0], pszUsageIdentifier);
 519             usage->cUsageIdentifier = 1;
 520             ret = CertSetEnhancedKeyUsage(pCertContext, usage);
 521             CryptMemFree(usage);
 522         }
 523         else
 524             ret = FALSE;
 525     }
 526     return ret;
 527 }
 528
 529 BOOL WINAPI CertRemoveEnhancedKeyUsageIdentifier(PCCERT_CONTEXT pCertContext,
 530  LPCSTR pszUsageIdentifier)
 531 {
 532     BOOL ret;
 533     DWORD size;
 534     CERT_ENHKEY_USAGE usage;
 535
 536     TRACE("(%p, %s)\n", pCertContext, debugstr_a(pszUsageIdentifier));
 537
 538     size = sizeof(usage);
 539     ret = CertGetEnhancedKeyUsage(pCertContext,
 540      CERT_FIND_PROP_ONLY_ENHKEY_USAGE_FLAG, &usage, &size);
 541     if (!ret && GetLastError() == ERROR_MORE_DATA)
 542     {
 543         PCERT_ENHKEY_USAGE pUsage = CryptMemAlloc(size);
 544
 545         if (pUsage)
 546         {
 547             ret = CertGetEnhancedKeyUsage(pCertContext,
 548              CERT_FIND_PROP_ONLY_ENHKEY_USAGE_FLAG, pUsage, &size);
 549             if (ret)
 550             {
 551                 if (pUsage->cUsageIdentifier)
 552                 {
 553                     DWORD i;
 554                     BOOL found = FALSE;
 555
 556                     for (i = 0; i < pUsage->cUsageIdentifier; i++)
 557                     {
 558                         if (!strcmp(pUsage->rgpszUsageIdentifier[i],
 559                          pszUsageIdentifier))
 560                             found = TRUE;
 561                         if (found && i < pUsage->cUsageIdentifier - 1)
 562                             pUsage->rgpszUsageIdentifier[i] =
 563                              pUsage->rgpszUsageIdentifier[i + 1];
 564                     }
 565                     pUsage->cUsageIdentifier--;
 566                     /* Remove the usage if it's empty */
 567                     if (pUsage->cUsageIdentifier)
 568                         ret = CertSetEnhancedKeyUsage(pCertContext, pUsage);
 569                     else
 570                         ret = CertSetEnhancedKeyUsage(pCertContext, NULL);
 571                 }
 572             }
 573             CryptMemFree(pUsage);
 574         }
 575         else
 576             ret = FALSE;
 577     }
 578     else
 579     {
 580         /* it fit in an empty usage, therefore there's nothing to remove */
 581         ret = TRUE;
 582     }
 583     return ret;
 584 }