dlls/crypt32/chain.c

   1 /*
   2  * Copyright 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  17  *
  18  */
  19 #include <stdarg.h>
  20 #define NONAMELESSUNION
  21 #include "windef.h"
  22 #include "winbase.h"
  23 #include "wincrypt.h"
  24 #include "wine/debug.h"
  25 #include "crypt32_private.h"
  26
  27 WINE_DEFAULT_DEBUG_CHANNEL(crypt);
  28
  29 #define DEFAULT_CYCLE_MODULUS 7
  30
  31 static HCERTCHAINENGINE CRYPT_defaultChainEngine;
  32
  33 /* This represents a subset of a certificate chain engine:  it doesn't include
  34  * the "hOther" store described by MSDN, because I'm not sure how that's used.
  35  * It also doesn't include the "hTrust" store, because I don't yet implement
  36  * CTLs or complex certificate chains.
  37  */
  38 typedef struct _CertificateChainEngine
  39 {
  40     LONG       ref;
  41     HCERTSTORE hRoot;
  42     HCERTSTORE hWorld;
  43     DWORD      dwFlags;
  44     DWORD      dwUrlRetrievalTimeout;
  45     DWORD      MaximumCachedCertificates;
  46     DWORD      CycleDetectionModulus;
  47 } CertificateChainEngine, *PCertificateChainEngine;
  48
  49 static inline void CRYPT_AddStoresToCollection(HCERTSTORE collection,
  50  DWORD cStores, HCERTSTORE *stores)
  51 {
  52     DWORD i;
  53
  54     for (i = 0; i < cStores; i++)
  55         CertAddStoreToCollection(collection, stores[i], 0, 0);
  56 }
  57
  58 static inline void CRYPT_CloseStores(DWORD cStores, HCERTSTORE *stores)
  59 {
  60     DWORD i;
  61
  62     for (i = 0; i < cStores; i++)
  63         CertCloseStore(stores[i], 0);
  64 }
  65
  66 static const WCHAR rootW[] = { 'R','o','o','t',0 };
  67
  68 static BOOL CRYPT_CheckRestrictedRoot(HCERTSTORE store)
  69 {
  70     BOOL ret = TRUE;
  71
  72     if (store)
  73     {
  74         HCERTSTORE rootStore = CertOpenSystemStoreW(0, rootW);
  75         PCCERT_CONTEXT cert = NULL, check;
  76         BYTE hash[20];
  77         DWORD size;
  78
  79         do {
  80             cert = CertEnumCertificatesInStore(store, cert);
  81             if (cert)
  82             {
  83                 size = sizeof(hash);
  84
  85                 ret = CertGetCertificateContextProperty(cert, CERT_HASH_PROP_ID,
  86                  hash, &size);
  87                 if (ret)
  88                 {
  89                     CRYPT_HASH_BLOB blob = { sizeof(hash), hash };
  90
  91                     check = CertFindCertificateInStore(rootStore,
  92                      cert->dwCertEncodingType, 0, CERT_FIND_SHA1_HASH, &blob,
  93                      NULL);
  94                     if (!check)
  95                         ret = FALSE;
  96                     else
  97                         CertFreeCertificateContext(check);
  98                 }
  99             }
 100         } while (ret && cert);
 101         if (cert)
 102             CertFreeCertificateContext(cert);
 103         CertCloseStore(rootStore, 0);
 104     }
 105     return ret;
 106 }
 107
 108 HCERTCHAINENGINE CRYPT_CreateChainEngine(HCERTSTORE root,
 109  PCERT_CHAIN_ENGINE_CONFIG pConfig)
 110 {
 111     static const WCHAR caW[] = { 'C','A',0 };
 112     static const WCHAR myW[] = { 'M','y',0 };
 113     static const WCHAR trustW[] = { 'T','r','u','s','t',0 };
 114     PCertificateChainEngine engine =
 115      CryptMemAlloc(sizeof(CertificateChainEngine));
 116
 117     if (engine)
 118     {
 119         HCERTSTORE worldStores[4];
 120
 121         engine->ref = 1;
 122         engine->hRoot = root;
 123         engine->hWorld = CertOpenStore(CERT_STORE_PROV_COLLECTION, 0, 0,
 124          CERT_STORE_CREATE_NEW_FLAG, NULL);
 125         worldStores[0] = CertDuplicateStore(engine->hRoot);
 126         worldStores[1] = CertOpenSystemStoreW(0, caW);
 127         worldStores[2] = CertOpenSystemStoreW(0, myW);
 128         worldStores[3] = CertOpenSystemStoreW(0, trustW);
 129         CRYPT_AddStoresToCollection(engine->hWorld,
 130          sizeof(worldStores) / sizeof(worldStores[0]), worldStores);
 131         CRYPT_AddStoresToCollection(engine->hWorld,
 132          pConfig->cAdditionalStore, pConfig->rghAdditionalStore);
 133         CRYPT_CloseStores(sizeof(worldStores) / sizeof(worldStores[0]),
 134          worldStores);
 135         engine->dwFlags = pConfig->dwFlags;
 136         engine->dwUrlRetrievalTimeout = pConfig->dwUrlRetrievalTimeout;
 137         engine->MaximumCachedCertificates =
 138          pConfig->MaximumCachedCertificates;
 139         if (pConfig->CycleDetectionModulus)
 140             engine->CycleDetectionModulus = pConfig->CycleDetectionModulus;
 141         else
 142             engine->CycleDetectionModulus = DEFAULT_CYCLE_MODULUS;
 143     }
 144     return (HCERTCHAINENGINE)engine;
 145 }
 146
 147 BOOL WINAPI CertCreateCertificateChainEngine(PCERT_CHAIN_ENGINE_CONFIG pConfig,
 148  HCERTCHAINENGINE *phChainEngine)
 149 {
 150     BOOL ret;
 151
 152     TRACE("(%p, %p)\n", pConfig, phChainEngine);
 153
 154     if (pConfig->cbSize != sizeof(*pConfig))
 155     {
 156         SetLastError(E_INVALIDARG);
 157         return FALSE;
 158     }
 159     *phChainEngine = NULL;
 160     ret = CRYPT_CheckRestrictedRoot(pConfig->hRestrictedRoot);
 161     if (ret)
 162     {
 163         HCERTSTORE root;
 164         HCERTCHAINENGINE engine;
 165
 166         if (pConfig->hRestrictedRoot)
 167             root = CertDuplicateStore(pConfig->hRestrictedRoot);
 168         else
 169             root = CertOpenSystemStoreW(0, rootW);
 170         engine = CRYPT_CreateChainEngine(root, pConfig);
 171         if (engine)
 172         {
 173             *phChainEngine = engine;
 174             ret = TRUE;
 175         }
 176         else
 177             ret = FALSE;
 178     }
 179     return ret;
 180 }
 181
 182 VOID WINAPI CertFreeCertificateChainEngine(HCERTCHAINENGINE hChainEngine)
 183 {
 184     PCertificateChainEngine engine = (PCertificateChainEngine)hChainEngine;
 185
 186     TRACE("(%p)\n", hChainEngine);
 187
 188     if (engine && InterlockedDecrement(&engine->ref) == 0)
 189     {
 190         CertCloseStore(engine->hWorld, 0);
 191         CertCloseStore(engine->hRoot, 0);
 192         CryptMemFree(engine);
 193     }
 194 }
 195
 196 static HCERTCHAINENGINE CRYPT_GetDefaultChainEngine(void)
 197 {
 198     if (!CRYPT_defaultChainEngine)
 199     {
 200         CERT_CHAIN_ENGINE_CONFIG config = { 0 };
 201         HCERTCHAINENGINE engine;
 202
 203         config.cbSize = sizeof(config);
 204         CertCreateCertificateChainEngine(&config, &engine);
 205         InterlockedCompareExchangePointer(&CRYPT_defaultChainEngine, engine,
 206          NULL);
 207         if (CRYPT_defaultChainEngine != engine)
 208             CertFreeCertificateChainEngine(engine);
 209     }
 210     return CRYPT_defaultChainEngine;
 211 }
 212
 213 void default_chain_engine_free(void)
 214 {
 215     CertFreeCertificateChainEngine(CRYPT_defaultChainEngine);
 216 }
 217
 218 typedef struct _CertificateChain
 219 {
 220     CERT_CHAIN_CONTEXT context;
 221     HCERTSTORE world;
 222     LONG ref;
 223 } CertificateChain, *PCertificateChain;
 224
 225 static inline BOOL CRYPT_IsCertificateSelfSigned(PCCERT_CONTEXT cert)
 226 {
 227     return CertCompareCertificateName(cert->dwCertEncodingType,
 228      &cert->pCertInfo->Subject, &cert->pCertInfo->Issuer);
 229 }
 230
 231 static void CRYPT_FreeChainElement(PCERT_CHAIN_ELEMENT element)
 232 {
 233     CertFreeCertificateContext(element->pCertContext);
 234     CryptMemFree(element);
 235 }
 236
 237 static void CRYPT_CheckSimpleChainForCycles(PCERT_SIMPLE_CHAIN chain)
 238 {
 239     DWORD i, j, cyclicCertIndex = 0;
 240
 241     /* O(n^2) - I don't think there's a faster way */
 242     for (i = 0; !cyclicCertIndex && i < chain->cElement; i++)
 243         for (j = i + 1; !cyclicCertIndex && j < chain->cElement; j++)
 244             if (CertCompareCertificate(X509_ASN_ENCODING,
 245              chain->rgpElement[i]->pCertContext->pCertInfo,
 246              chain->rgpElement[j]->pCertContext->pCertInfo))
 247                 cyclicCertIndex = j;
 248     if (cyclicCertIndex)
 249     {
 250         chain->rgpElement[cyclicCertIndex]->TrustStatus.dwErrorStatus
 251          |= CERT_TRUST_IS_CYCLIC;
 252         /* Release remaining certs */
 253         for (i = cyclicCertIndex + 1; i < chain->cElement; i++)
 254             CRYPT_FreeChainElement(chain->rgpElement[i]);
 255         /* Truncate chain */
 256         chain->cElement = cyclicCertIndex + 1;
 257     }
 258 }
 259
 260 /* Checks whether the chain is cyclic by examining the last element's status */
 261 static inline BOOL CRYPT_IsSimpleChainCyclic(PCERT_SIMPLE_CHAIN chain)
 262 {
 263     if (chain->cElement)
 264         return chain->rgpElement[chain->cElement - 1]->TrustStatus.dwErrorStatus
 265          & CERT_TRUST_IS_CYCLIC;
 266     else
 267         return FALSE;
 268 }
 269
 270 static inline void CRYPT_CombineTrustStatus(CERT_TRUST_STATUS *chainStatus,
 271  CERT_TRUST_STATUS *elementStatus)
 272 {
 273     /* Any error that applies to an element also applies to a chain.. */
 274     chainStatus->dwErrorStatus |= elementStatus->dwErrorStatus;
 275     /* but the bottom nibble of an element's info status doesn't apply to the
 276      * chain.
 277      */
 278     chainStatus->dwInfoStatus |= (elementStatus->dwInfoStatus & 0xfffffff0);
 279 }
 280
 281 static BOOL CRYPT_AddCertToSimpleChain(PCertificateChainEngine engine,
 282  PCERT_SIMPLE_CHAIN chain, PCCERT_CONTEXT cert, DWORD subjectInfoStatus)
 283 {
 284     BOOL ret = FALSE;
 285     PCERT_CHAIN_ELEMENT element = CryptMemAlloc(sizeof(CERT_CHAIN_ELEMENT));
 286
 287     if (element)
 288     {
 289         if (!chain->cElement)
 290             chain->rgpElement = CryptMemAlloc(sizeof(PCERT_CHAIN_ELEMENT));
 291         else
 292             chain->rgpElement = CryptMemRealloc(chain->rgpElement,
 293              (chain->cElement + 1) * sizeof(PCERT_CHAIN_ELEMENT));
 294         if (chain->rgpElement)
 295         {
 296             chain->rgpElement[chain->cElement++] = element;
 297             memset(element, 0, sizeof(CERT_CHAIN_ELEMENT));
 298             element->cbSize = sizeof(CERT_CHAIN_ELEMENT);
 299             element->pCertContext = CertDuplicateCertificateContext(cert);
 300             if (chain->cElement > 1)
 301                 chain->rgpElement[chain->cElement - 2]->TrustStatus.dwInfoStatus
 302                  = subjectInfoStatus;
 303             /* FIXME: initialize the rest of element */
 304             if (chain->cElement % engine->CycleDetectionModulus)
 305                 CRYPT_CheckSimpleChainForCycles(chain);
 306             CRYPT_CombineTrustStatus(&chain->TrustStatus,
 307              &element->TrustStatus);
 308             ret = TRUE;
 309         }
 310         else
 311             CryptMemFree(element);
 312     }
 313     return ret;
 314 }
 315
 316 static void CRYPT_FreeSimpleChain(PCERT_SIMPLE_CHAIN chain)
 317 {
 318     DWORD i;
 319
 320     for (i = 0; i < chain->cElement; i++)
 321         CRYPT_FreeChainElement(chain->rgpElement[i]);
 322     CryptMemFree(chain->rgpElement);
 323     CryptMemFree(chain);
 324 }
 325
 326 static void CRYPT_CheckTrustedStatus(HCERTSTORE hRoot,
 327  PCERT_CHAIN_ELEMENT rootElement)
 328 {
 329     BYTE hash[20];
 330     DWORD size = sizeof(hash);
 331     CRYPT_HASH_BLOB blob = { sizeof(hash), hash };
 332     PCCERT_CONTEXT trustedRoot;
 333
 334     CertGetCertificateContextProperty(rootElement->pCertContext,
 335      CERT_HASH_PROP_ID, hash, &size);
 336     trustedRoot = CertFindCertificateInStore(hRoot,
 337      rootElement->pCertContext->dwCertEncodingType, 0, CERT_FIND_SHA1_HASH,
 338      &blob, NULL);
 339     if (!trustedRoot)
 340         rootElement->TrustStatus.dwErrorStatus |=
 341          CERT_TRUST_IS_UNTRUSTED_ROOT;
 342     else
 343         CertFreeCertificateContext(trustedRoot);
 344 }
 345
 346 static void CRYPT_CheckRootCert(HCERTCHAINENGINE hRoot,
 347  PCERT_CHAIN_ELEMENT rootElement)
 348 {
 349     PCCERT_CONTEXT root = rootElement->pCertContext;
 350
 351     if (!CryptVerifyCertificateSignatureEx(0, root->dwCertEncodingType,
 352      CRYPT_VERIFY_CERT_SIGN_SUBJECT_CERT, (void *)root,
 353      CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT, (void *)root, 0, NULL))
 354     {
 355         TRACE("Last certificate's signature is invalid\n");
 356         rootElement->TrustStatus.dwErrorStatus |=
 357          CERT_TRUST_IS_NOT_SIGNATURE_VALID;
 358     }
 359     CRYPT_CheckTrustedStatus(hRoot, rootElement);
 360 }
 361
 362 /* Decodes a cert's basic constraints extension (either szOID_BASIC_CONSTRAINTS
 363  * or szOID_BASIC_CONSTRAINTS2, whichever is present) into a
 364  * CERT_BASIC_CONSTRAINTS2_INFO.  If it neither extension is present, sets
 365  * constraints->fCA to defaultIfNotSpecified.
 366  * Returns FALSE if the extension is present but couldn't be decoded.
 367  */
 368 static BOOL CRYPT_DecodeBasicConstraints(PCCERT_CONTEXT cert,
 369  CERT_BASIC_CONSTRAINTS2_INFO *constraints, BOOL defaultIfNotSpecified)
 370 {
 371     BOOL ret = TRUE;
 372     PCERT_EXTENSION ext = CertFindExtension(szOID_BASIC_CONSTRAINTS,
 373      cert->pCertInfo->cExtension, cert->pCertInfo->rgExtension);
 374
 375     constraints->fPathLenConstraint = FALSE;
 376     if (ext)
 377     {
 378         CERT_BASIC_CONSTRAINTS_INFO *info;
 379         DWORD size = 0;
 380
 381         ret = CryptDecodeObjectEx(X509_ASN_ENCODING, szOID_BASIC_CONSTRAINTS,
 382          ext->Value.pbData, ext->Value.cbData, CRYPT_DECODE_ALLOC_FLAG,
 383          NULL, (LPBYTE)&info, &size);
 384         if (ret)
 385         {
 386             if (info->SubjectType.cbData == 1)
 387                 constraints->fCA =
 388                  info->SubjectType.pbData[0] & CERT_CA_SUBJECT_FLAG;
 389             LocalFree(info);
 390         }
 391     }
 392     else
 393     {
 394         ext = CertFindExtension(szOID_BASIC_CONSTRAINTS2,
 395          cert->pCertInfo->cExtension, cert->pCertInfo->rgExtension);
 396         if (ext)
 397         {
 398             DWORD size = sizeof(CERT_BASIC_CONSTRAINTS2_INFO);
 399
 400             ret = CryptDecodeObjectEx(X509_ASN_ENCODING,
 401              szOID_BASIC_CONSTRAINTS2, ext->Value.pbData, ext->Value.cbData,
 402              0, NULL, constraints, &size);
 403         }
 404         else
 405             constraints->fCA = defaultIfNotSpecified;
 406     }
 407     return ret;
 408 }
 409
 410 /* Checks element's basic constraints to see if it can act as a CA, with
 411  * remainingCAs CAs left in this chain.  Updates chainConstraints with the
 412  * element's constraints, if:
 413  * 1. chainConstraints doesn't have a path length constraint, or
 414  * 2. element's path length constraint is smaller than chainConstraints's
 415  * Sets *pathLengthConstraintViolated to TRUE if a path length violation
 416  * occurs.
 417  * Returns TRUE if the element can be a CA, and the length of the remaining
 418  * chain is valid.
 419  */
 420 static BOOL CRYPT_CheckBasicConstraintsForCA(PCCERT_CONTEXT cert,
 421  CERT_BASIC_CONSTRAINTS2_INFO *chainConstraints, DWORD remainingCAs,
 422  BOOL *pathLengthConstraintViolated)
 423 {
 424     BOOL validBasicConstraints;
 425     CERT_BASIC_CONSTRAINTS2_INFO constraints;
 426
 427     if ((validBasicConstraints = CRYPT_DecodeBasicConstraints(cert,
 428      &constraints, TRUE)))
 429     {
 430         if (!constraints.fCA)
 431         {
 432             TRACE("chain element %d can't be a CA\n", remainingCAs + 1);
 433             validBasicConstraints = FALSE;
 434         }
 435         else if (constraints.fPathLenConstraint)
 436         {
 437             /* If the element has path length constraints, they apply to the
 438              * entire remaining chain.
 439              */
 440             if (!chainConstraints->fPathLenConstraint ||
 441              constraints.dwPathLenConstraint <
 442              chainConstraints->dwPathLenConstraint)
 443             {
 444                 TRACE("setting path length constraint to %d\n",
 445                  chainConstraints->dwPathLenConstraint);
 446                 chainConstraints->fPathLenConstraint = TRUE;
 447                 chainConstraints->dwPathLenConstraint =
 448                  constraints.dwPathLenConstraint;
 449             }
 450         }
 451     }
 452     if (chainConstraints->fPathLenConstraint &&
 453      remainingCAs > chainConstraints->dwPathLenConstraint)
 454     {
 455         TRACE("remaining CAs %d exceed max path length %d\n", remainingCAs,
 456          chainConstraints->dwPathLenConstraint);
 457         validBasicConstraints = FALSE;
 458         *pathLengthConstraintViolated = TRUE;
 459     }
 460     return validBasicConstraints;
 461 }
 462
 463 static void CRYPT_CheckSimpleChain(PCertificateChainEngine engine,
 464  PCERT_SIMPLE_CHAIN chain, LPFILETIME time)
 465 {
 466     PCERT_CHAIN_ELEMENT rootElement = chain->rgpElement[chain->cElement - 1];
 467     int i;
 468     BOOL pathLengthConstraintViolated = FALSE;
 469     CERT_BASIC_CONSTRAINTS2_INFO constraints = { TRUE, FALSE, 0 };
 470
 471     for (i = chain->cElement - 1; i >= 0; i--)
 472     {
 473         if (CertVerifyTimeValidity(time,
 474          chain->rgpElement[i]->pCertContext->pCertInfo) != 0)
 475             chain->rgpElement[i]->TrustStatus.dwErrorStatus |=
 476              CERT_TRUST_IS_NOT_TIME_VALID;
 477         if (i != 0)
 478         {
 479             /* Check the signature of the cert this issued */
 480             if (!CryptVerifyCertificateSignatureEx(0, X509_ASN_ENCODING,
 481              CRYPT_VERIFY_CERT_SIGN_SUBJECT_CERT,
 482              (void *)chain->rgpElement[i - 1]->pCertContext,
 483              CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT,
 484              (void *)chain->rgpElement[i]->pCertContext, 0, NULL))
 485                 chain->rgpElement[i - 1]->TrustStatus.dwErrorStatus |=
 486                  CERT_TRUST_IS_NOT_SIGNATURE_VALID;
 487             /* Once a path length constraint has been violated, every remaining
 488              * CA cert's basic constraints is considered invalid.
 489              */
 490             if (pathLengthConstraintViolated)
 491                 chain->rgpElement[i]->TrustStatus.dwErrorStatus |=
 492                  CERT_TRUST_INVALID_BASIC_CONSTRAINTS;
 493             else if (!CRYPT_CheckBasicConstraintsForCA(
 494              chain->rgpElement[i]->pCertContext, &constraints, i - 1,
 495              &pathLengthConstraintViolated))
 496                 chain->rgpElement[i]->TrustStatus.dwErrorStatus |=
 497                  CERT_TRUST_INVALID_BASIC_CONSTRAINTS;
 498             else if (constraints.fPathLenConstraint &&
 499              constraints.dwPathLenConstraint)
 500             {
 501                 /* This one's valid - decrement max length */
 502                 constraints.dwPathLenConstraint--;
 503             }
 504         }
 505         /* FIXME: check valid usages and name constraints */
 506         CRYPT_CombineTrustStatus(&chain->TrustStatus,
 507          &chain->rgpElement[i]->TrustStatus);
 508     }
 509     if (CRYPT_IsCertificateSelfSigned(rootElement->pCertContext))
 510     {
 511         rootElement->TrustStatus.dwInfoStatus |=
 512          CERT_TRUST_IS_SELF_SIGNED | CERT_TRUST_HAS_NAME_MATCH_ISSUER;
 513         CRYPT_CheckRootCert(engine->hRoot, rootElement);
 514     }
 515     /* FIXME: check revocation of every cert with CertVerifyRevocation */
 516     CRYPT_CombineTrustStatus(&chain->TrustStatus, &rootElement->TrustStatus);
 517 }
 518
 519 static PCCERT_CONTEXT CRYPT_GetIssuer(HCERTSTORE store, PCCERT_CONTEXT subject,
 520  PCCERT_CONTEXT prevIssuer, DWORD *infoStatus)
 521 {
 522     PCCERT_CONTEXT issuer = NULL;
 523     PCERT_EXTENSION ext;
 524     DWORD size;
 525
 526     *infoStatus = 0;
 527     if ((ext = CertFindExtension(szOID_AUTHORITY_KEY_IDENTIFIER,
 528      subject->pCertInfo->cExtension, subject->pCertInfo->rgExtension)))
 529     {
 530         CERT_AUTHORITY_KEY_ID_INFO *info;
 531         BOOL ret;
 532
 533         ret = CryptDecodeObjectEx(subject->dwCertEncodingType,
 534          X509_AUTHORITY_KEY_ID, ext->Value.pbData, ext->Value.cbData,
 535          CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG, NULL,
 536          &info, &size);
 537         if (ret)
 538         {
 539             CERT_ID id;
 540
 541             if (info->CertIssuer.cbData && info->CertSerialNumber.cbData)
 542             {
 543                 id.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
 544                 memcpy(&id.u.IssuerSerialNumber.Issuer, &info->CertIssuer,
 545                  sizeof(CERT_NAME_BLOB));
 546                 memcpy(&id.u.IssuerSerialNumber.SerialNumber,
 547                  &info->CertSerialNumber, sizeof(CRYPT_INTEGER_BLOB));
 548                 issuer = CertFindCertificateInStore(store,
 549                  subject->dwCertEncodingType, 0, CERT_FIND_CERT_ID, &id,
 550                  prevIssuer);
 551                 if (issuer)
 552                     *infoStatus = CERT_TRUST_HAS_EXACT_MATCH_ISSUER;
 553             }
 554             else if (info->KeyId.cbData)
 555             {
 556                 id.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
 557                 memcpy(&id.u.KeyId, &info->KeyId, sizeof(CRYPT_HASH_BLOB));
 558                 issuer = CertFindCertificateInStore(store,
 559                  subject->dwCertEncodingType, 0, CERT_FIND_CERT_ID, &id,
 560                  prevIssuer);
 561                 if (issuer)
 562                     *infoStatus = CERT_TRUST_HAS_KEY_MATCH_ISSUER;
 563             }
 564             LocalFree(info);
 565         }
 566     }
 567     else if ((ext = CertFindExtension(szOID_AUTHORITY_KEY_IDENTIFIER2,
 568      subject->pCertInfo->cExtension, subject->pCertInfo->rgExtension)))
 569     {
 570         CERT_AUTHORITY_KEY_ID2_INFO *info;
 571         BOOL ret;
 572
 573         ret = CryptDecodeObjectEx(subject->dwCertEncodingType,
 574          X509_AUTHORITY_KEY_ID2, ext->Value.pbData, ext->Value.cbData,
 575          CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG, NULL,
 576          &info, &size);
 577         if (ret)
 578         {
 579             CERT_ID id;
 580
 581             if (info->AuthorityCertIssuer.cAltEntry &&
 582              info->AuthorityCertSerialNumber.cbData)
 583             {
 584                 PCERT_ALT_NAME_ENTRY directoryName = NULL;
 585                 DWORD i;
 586
 587                 for (i = 0; !directoryName &&
 588                  i < info->AuthorityCertIssuer.cAltEntry; i++)
 589                     if (info->AuthorityCertIssuer.rgAltEntry[i].dwAltNameChoice
 590                      == CERT_ALT_NAME_DIRECTORY_NAME)
 591                         directoryName =
 592                          &info->AuthorityCertIssuer.rgAltEntry[i];
 593                 if (directoryName)
 594                 {
 595                     id.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
 596                     memcpy(&id.u.IssuerSerialNumber.Issuer,
 597                      &directoryName->u.DirectoryName, sizeof(CERT_NAME_BLOB));
 598                     memcpy(&id.u.IssuerSerialNumber.SerialNumber,
 599                      &info->AuthorityCertSerialNumber,
 600                      sizeof(CRYPT_INTEGER_BLOB));
 601                     issuer = CertFindCertificateInStore(store,
 602                      subject->dwCertEncodingType, 0, CERT_FIND_CERT_ID, &id,
 603                      prevIssuer);
 604                     if (issuer)
 605                         *infoStatus = CERT_TRUST_HAS_EXACT_MATCH_ISSUER;
 606                 }
 607                 else
 608                     FIXME("no supported name type in authority key id2\n");
 609             }
 610             else if (info->KeyId.cbData)
 611             {
 612                 id.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
 613                 memcpy(&id.u.KeyId, &info->KeyId, sizeof(CRYPT_HASH_BLOB));
 614                 issuer = CertFindCertificateInStore(store,
 615                  subject->dwCertEncodingType, 0, CERT_FIND_CERT_ID, &id,
 616                  prevIssuer);
 617                 if (issuer)
 618                     *infoStatus = CERT_TRUST_HAS_KEY_MATCH_ISSUER;
 619             }
 620             LocalFree(info);
 621         }
 622     }
 623     else
 624     {
 625         issuer = CertFindCertificateInStore(store,
 626          subject->dwCertEncodingType, 0, CERT_FIND_SUBJECT_NAME,
 627          &subject->pCertInfo->Issuer, prevIssuer);
 628         if (issuer)
 629             *infoStatus = CERT_TRUST_HAS_NAME_MATCH_ISSUER;
 630     }
 631     return issuer;
 632 }
 633
 634 /* Builds a simple chain by finding an issuer for the last cert in the chain,
 635  * until reaching a self-signed cert, or until no issuer can be found.
 636  */
 637 static BOOL CRYPT_BuildSimpleChain(PCertificateChainEngine engine,
 638  HCERTSTORE world, PCERT_SIMPLE_CHAIN chain)
 639 {
 640     BOOL ret = TRUE;
 641     PCCERT_CONTEXT cert = chain->rgpElement[chain->cElement - 1]->pCertContext;
 642
 643     while (ret && !CRYPT_IsSimpleChainCyclic(chain) &&
 644      !CRYPT_IsCertificateSelfSigned(cert))
 645     {
 646         DWORD infoStatus;
 647         PCCERT_CONTEXT issuer = CRYPT_GetIssuer(world, cert, NULL, &infoStatus);
 648
 649         if (issuer)
 650         {
 651             ret = CRYPT_AddCertToSimpleChain(engine, chain, issuer, infoStatus);
 652             cert = issuer;
 653         }
 654         else
 655         {
 656             TRACE("Couldn't find issuer, halting chain creation\n");
 657             break;
 658         }
 659     }
 660     return ret;
 661 }
 662
 663 static BOOL CRYPT_GetSimpleChainForCert(PCertificateChainEngine engine,
 664  HCERTSTORE world, PCCERT_CONTEXT cert, LPFILETIME pTime,
 665  PCERT_SIMPLE_CHAIN *ppChain)
 666 {
 667     BOOL ret = FALSE;
 668     PCERT_SIMPLE_CHAIN chain;
 669
 670     TRACE("(%p, %p, %p, %p)\n", engine, world, cert, pTime);
 671
 672     chain = CryptMemAlloc(sizeof(CERT_SIMPLE_CHAIN));
 673     if (chain)
 674     {
 675         memset(chain, 0, sizeof(CERT_SIMPLE_CHAIN));
 676         chain->cbSize = sizeof(CERT_SIMPLE_CHAIN);
 677         ret = CRYPT_AddCertToSimpleChain(engine, chain, cert, 0);
 678         if (ret)
 679         {
 680             ret = CRYPT_BuildSimpleChain(engine, world, chain);
 681             if (ret)
 682                 CRYPT_CheckSimpleChain(engine, chain, pTime);
 683         }
 684         if (!ret)
 685         {
 686             CRYPT_FreeSimpleChain(chain);
 687             chain = NULL;
 688         }
 689         *ppChain = chain;
 690     }
 691     return ret;
 692 }
 693
 694 static BOOL CRYPT_BuildCandidateChainFromCert(HCERTCHAINENGINE hChainEngine,
 695  PCCERT_CONTEXT cert, LPFILETIME pTime, HCERTSTORE hAdditionalStore,
 696  PCertificateChain *ppChain)
 697 {
 698     PCertificateChainEngine engine = (PCertificateChainEngine)hChainEngine;
 699     PCERT_SIMPLE_CHAIN simpleChain = NULL;
 700     HCERTSTORE world;
 701     BOOL ret;
 702
 703     world = CertOpenStore(CERT_STORE_PROV_COLLECTION, 0, 0,
 704      CERT_STORE_CREATE_NEW_FLAG, NULL);
 705     CertAddStoreToCollection(world, engine->hWorld, 0, 0);
 706     if (hAdditionalStore)
 707         CertAddStoreToCollection(world, hAdditionalStore, 0, 0);
 708     /* FIXME: only simple chains are supported for now, as CTLs aren't
 709      * supported yet.
 710      */
 711     if ((ret = CRYPT_GetSimpleChainForCert(engine, world, cert, pTime,
 712      &simpleChain)))
 713     {
 714         PCertificateChain chain = CryptMemAlloc(sizeof(CertificateChain));
 715
 716         if (chain)
 717         {
 718             chain->ref = 1;
 719             chain->world = world;
 720             chain->context.cbSize = sizeof(CERT_CHAIN_CONTEXT);
 721             memcpy(&chain->context.TrustStatus, &simpleChain->TrustStatus,
 722              sizeof(CERT_TRUST_STATUS));
 723             chain->context.cChain = 1;
 724             chain->context.rgpChain = CryptMemAlloc(sizeof(PCERT_SIMPLE_CHAIN));
 725             chain->context.rgpChain[0] = simpleChain;
 726             chain->context.cLowerQualityChainContext = 0;
 727             chain->context.rgpLowerQualityChainContext = NULL;
 728             chain->context.fHasRevocationFreshnessTime = FALSE;
 729             chain->context.dwRevocationFreshnessTime = 0;
 730         }
 731         else
 732             ret = FALSE;
 733         *ppChain = chain;
 734     }
 735     return ret;
 736 }
 737
 738 /* Makes and returns a copy of chain, up to and including element iElement. */
 739 static PCERT_SIMPLE_CHAIN CRYPT_CopySimpleChainToElement(
 740  PCERT_SIMPLE_CHAIN chain, DWORD iElement)
 741 {
 742     PCERT_SIMPLE_CHAIN copy = CryptMemAlloc(sizeof(CERT_SIMPLE_CHAIN));
 743
 744     if (copy)
 745     {
 746         memset(copy, 0, sizeof(CERT_SIMPLE_CHAIN));
 747         copy->cbSize = sizeof(CERT_SIMPLE_CHAIN);
 748         copy->rgpElement =
 749          CryptMemAlloc((iElement + 1) * sizeof(PCERT_CHAIN_ELEMENT));
 750         if (copy->rgpElement)
 751         {
 752             DWORD i;
 753             BOOL ret = TRUE;
 754
 755             memset(copy->rgpElement, 0,
 756              (iElement + 1) * sizeof(PCERT_CHAIN_ELEMENT));
 757             for (i = 0; ret && i <= iElement; i++)
 758             {
 759                 PCERT_CHAIN_ELEMENT element =
 760                  CryptMemAlloc(sizeof(CERT_CHAIN_ELEMENT));
 761
 762                 if (element)
 763                 {
 764                     memcpy(element, chain->rgpElement[i],
 765                      sizeof(CERT_CHAIN_ELEMENT));
 766                     element->pCertContext = CertDuplicateCertificateContext(
 767                      chain->rgpElement[i]->pCertContext);
 768                     /* Reset the trust status of the copied element, it'll get
 769                      * rechecked after the new chain is done.
 770                      */
 771                     memset(&element->TrustStatus, 0, sizeof(CERT_TRUST_STATUS));
 772                     copy->rgpElement[copy->cElement++] = element;
 773                 }
 774                 else
 775                     ret = FALSE;
 776             }
 777             if (!ret)
 778             {
 779                 for (i = 0; i <= iElement; i++)
 780                     CryptMemFree(copy->rgpElement[i]);
 781                 CryptMemFree(copy->rgpElement);
 782                 CryptMemFree(copy);
 783                 copy = NULL;
 784             }
 785         }
 786         else
 787         {
 788             CryptMemFree(copy);
 789             copy = NULL;
 790         }
 791     }
 792     return copy;
 793 }
 794
 795 static void CRYPT_FreeLowerQualityChains(PCertificateChain chain)
 796 {
 797     DWORD i;
 798
 799     for (i = 0; i < chain->context.cLowerQualityChainContext; i++)
 800         CertFreeCertificateChain(chain->context.rgpLowerQualityChainContext[i]);
 801     CryptMemFree(chain->context.rgpLowerQualityChainContext);
 802 }
 803
 804 static void CRYPT_FreeChainContext(PCertificateChain chain)
 805 {
 806     DWORD i;
 807
 808     CRYPT_FreeLowerQualityChains(chain);
 809     for (i = 0; i < chain->context.cChain; i++)
 810         CRYPT_FreeSimpleChain(chain->context.rgpChain[i]);
 811     CryptMemFree(chain->context.rgpChain);
 812     CertCloseStore(chain->world, 0);
 813     CryptMemFree(chain);
 814 }
 815
 816 /* Makes and returns a copy of chain, up to and including element iElement of
 817  * simple chain iChain.
 818  */
 819 static PCertificateChain CRYPT_CopyChainToElement(PCertificateChain chain,
 820  DWORD iChain, DWORD iElement)
 821 {
 822     PCertificateChain copy = CryptMemAlloc(sizeof(CertificateChain));
 823
 824     if (copy)
 825     {
 826         copy->ref = 1;
 827         copy->world = CertDuplicateStore(chain->world);
 828         copy->context.cbSize = sizeof(CERT_CHAIN_CONTEXT);
 829         /* Leave the trust status of the copied chain unset, it'll get
 830          * rechecked after the new chain is done.
 831          */
 832         memset(&copy->context.TrustStatus, 0, sizeof(CERT_TRUST_STATUS));
 833         copy->context.cLowerQualityChainContext = 0;
 834         copy->context.rgpLowerQualityChainContext = NULL;
 835         copy->context.fHasRevocationFreshnessTime = FALSE;
 836         copy->context.dwRevocationFreshnessTime = 0;
 837         copy->context.rgpChain = CryptMemAlloc(
 838          (iChain + 1) * sizeof(PCERT_SIMPLE_CHAIN));
 839         if (copy->context.rgpChain)
 840         {
 841             BOOL ret = TRUE;
 842             DWORD i;
 843
 844             memset(copy->context.rgpChain, 0,
 845              (iChain + 1) * sizeof(PCERT_SIMPLE_CHAIN));
 846             if (iChain)
 847             {
 848                 for (i = 0; ret && iChain && i < iChain - 1; i++)
 849                 {
 850                     copy->context.rgpChain[i] =
 851                      CRYPT_CopySimpleChainToElement(chain->context.rgpChain[i],
 852                      chain->context.rgpChain[i]->cElement - 1);
 853                     if (!copy->context.rgpChain[i])
 854                         ret = FALSE;
 855                 }
 856             }
 857             else
 858                 i = 0;
 859             if (ret)
 860             {
 861                 copy->context.rgpChain[i] =
 862                  CRYPT_CopySimpleChainToElement(chain->context.rgpChain[i],
 863                  iElement);
 864                 if (!copy->context.rgpChain[i])
 865                     ret = FALSE;
 866             }
 867             if (!ret)
 868             {
 869                 CRYPT_FreeChainContext(copy);
 870                 copy = NULL;
 871             }
 872             else
 873                 copy->context.cChain = iChain + 1;
 874         }
 875         else
 876         {
 877             CryptMemFree(copy);
 878             copy = NULL;
 879         }
 880     }
 881     return copy;
 882 }
 883
 884 static PCertificateChain CRYPT_BuildAlternateContextFromChain(
 885  HCERTCHAINENGINE hChainEngine, LPFILETIME pTime, HCERTSTORE hAdditionalStore,
 886  PCertificateChain chain)
 887 {
 888     PCertificateChainEngine engine = (PCertificateChainEngine)hChainEngine;
 889     PCertificateChain alternate;
 890
 891     TRACE("(%p, %p, %p, %p)\n", hChainEngine, pTime, hAdditionalStore, chain);
 892
 893     /* Always start with the last "lower quality" chain to ensure a consistent
 894      * order of alternate creation:
 895      */
 896     if (chain->context.cLowerQualityChainContext)
 897         chain = (PCertificateChain)chain->context.rgpLowerQualityChainContext[
 898          chain->context.cLowerQualityChainContext - 1];
 899     /* A chain with only one element can't have any alternates */
 900     if (chain->context.cChain <= 1 && chain->context.rgpChain[0]->cElement <= 1)
 901         alternate = NULL;
 902     else
 903     {
 904         DWORD i, j, infoStatus;
 905         PCCERT_CONTEXT alternateIssuer = NULL;
 906
 907         alternate = NULL;
 908         for (i = 0; !alternateIssuer && i < chain->context.cChain; i++)
 909             for (j = 0; !alternateIssuer &&
 910              j < chain->context.rgpChain[i]->cElement - 1; j++)
 911             {
 912                 PCCERT_CONTEXT subject =
 913                  chain->context.rgpChain[i]->rgpElement[j]->pCertContext;
 914                 PCCERT_CONTEXT prevIssuer = CertDuplicateCertificateContext(
 915                  chain->context.rgpChain[i]->rgpElement[j + 1]->pCertContext);
 916
 917                 alternateIssuer = CRYPT_GetIssuer(prevIssuer->hCertStore,
 918                  subject, prevIssuer, &infoStatus);
 919             }
 920         if (alternateIssuer)
 921         {
 922             i--;
 923             j--;
 924             alternate = CRYPT_CopyChainToElement(chain, i, j);
 925             if (alternate)
 926             {
 927                 BOOL ret = CRYPT_AddCertToSimpleChain(engine,
 928                  alternate->context.rgpChain[i], alternateIssuer, infoStatus);
 929
 930                 if (ret)
 931                 {
 932                     ret = CRYPT_BuildSimpleChain(engine, alternate->world,
 933                      alternate->context.rgpChain[i]);
 934                     if (ret)
 935                         CRYPT_CheckSimpleChain(engine,
 936                          alternate->context.rgpChain[i], pTime);
 937                     CRYPT_CombineTrustStatus(&alternate->context.TrustStatus,
 938                      &alternate->context.rgpChain[i]->TrustStatus);
 939                 }
 940                 if (!ret)
 941                 {
 942                     CRYPT_FreeChainContext(alternate);
 943                     alternate = NULL;
 944                 }
 945             }
 946         }
 947     }
 948     TRACE("%p\n", alternate);
 949     return alternate;
 950 }
 951
 952 #define CHAIN_QUALITY_SIGNATURE_VALID 8
 953 #define CHAIN_QUALITY_TIME_VALID      4
 954 #define CHAIN_QUALITY_COMPLETE_CHAIN  2
 955 #define CHAIN_QUALITY_TRUSTED_ROOT    1
 956
 957 #define CHAIN_QUALITY_HIGHEST \
 958  CHAIN_QUALITY_SIGNATURE_VALID | CHAIN_QUALITY_TIME_VALID | \
 959  CHAIN_QUALITY_COMPLETE_CHAIN | CHAIN_QUALITY_TRUSTED_ROOT
 960
 961 #define IS_TRUST_ERROR_SET(TrustStatus, bits) \
 962  (TrustStatus)->dwErrorStatus & (bits)
 963
 964 static DWORD CRYPT_ChainQuality(PCertificateChain chain)
 965 {
 966     DWORD quality = CHAIN_QUALITY_HIGHEST;
 967
 968     if (IS_TRUST_ERROR_SET(&chain->context.TrustStatus,
 969      CERT_TRUST_IS_UNTRUSTED_ROOT))
 970         quality &= ~CHAIN_QUALITY_TRUSTED_ROOT;
 971     if (IS_TRUST_ERROR_SET(&chain->context.TrustStatus,
 972      CERT_TRUST_IS_PARTIAL_CHAIN))
 973     if (chain->context.TrustStatus.dwErrorStatus & CERT_TRUST_IS_PARTIAL_CHAIN)
 974         quality &= ~CHAIN_QUALITY_COMPLETE_CHAIN;
 975     if (IS_TRUST_ERROR_SET(&chain->context.TrustStatus,
 976      CERT_TRUST_IS_NOT_TIME_VALID | CERT_TRUST_IS_NOT_TIME_NESTED))
 977         quality &= ~CHAIN_QUALITY_TIME_VALID;
 978     if (IS_TRUST_ERROR_SET(&chain->context.TrustStatus,
 979      CERT_TRUST_IS_NOT_SIGNATURE_VALID))
 980         quality &= ~CHAIN_QUALITY_SIGNATURE_VALID;
 981     return quality;
 982 }
 983
 984 /* Chooses the highest quality chain among chain and its "lower quality"
 985  * alternate chains.  Returns the highest quality chain, with all other
 986  * chains as lower quality chains of it.
 987  */
 988 static PCertificateChain CRYPT_ChooseHighestQualityChain(
 989  PCertificateChain chain)
 990 {
 991     DWORD i;
 992
 993     /* There are always only two chains being considered:  chain, and an
 994      * alternate at chain->rgpLowerQualityChainContext[i].  If the alternate
 995      * has a higher quality than chain, the alternate gets assigned the lower
 996      * quality contexts, with chain taking the alternate's place among the
 997      * lower quality contexts.
 998      */
 999     for (i = 0; i < chain->context.cLowerQualityChainContext; i++)
1000     {
1001         PCertificateChain alternate =
1002          (PCertificateChain)chain->context.rgpLowerQualityChainContext[i];
1003
1004         if (CRYPT_ChainQuality(alternate) > CRYPT_ChainQuality(chain))
1005         {
1006             alternate->context.cLowerQualityChainContext =
1007              chain->context.cLowerQualityChainContext;
1008             alternate->context.rgpLowerQualityChainContext =
1009              chain->context.rgpLowerQualityChainContext;
1010             alternate->context.rgpLowerQualityChainContext[i] =
1011              (PCCERT_CHAIN_CONTEXT)chain;
1012             chain = alternate;
1013         }
1014     }
1015     return chain;
1016 }
1017
1018 static BOOL CRYPT_AddAlternateChainToChain(PCertificateChain chain,
1019  PCertificateChain alternate)
1020 {
1021     BOOL ret;
1022
1023     if (chain->context.cLowerQualityChainContext)
1024         chain->context.rgpLowerQualityChainContext =
1025          CryptMemRealloc(chain->context.rgpLowerQualityChainContext,
1026          (chain->context.cLowerQualityChainContext + 1) *
1027          sizeof(PCCERT_CHAIN_CONTEXT));
1028     else
1029         chain->context.rgpLowerQualityChainContext =
1030          CryptMemAlloc(sizeof(PCCERT_CHAIN_CONTEXT));
1031     if (chain->context.rgpLowerQualityChainContext)
1032     {
1033         chain->context.rgpLowerQualityChainContext[
1034          chain->context.cLowerQualityChainContext++] =
1035          (PCCERT_CHAIN_CONTEXT)alternate;
1036         ret = TRUE;
1037     }
1038     else
1039         ret = FALSE;
1040     return ret;
1041 }
1042
1043 typedef struct _CERT_CHAIN_PARA_NO_EXTRA_FIELDS {
1044     DWORD            cbSize;
1045     CERT_USAGE_MATCH RequestedUsage;
1046 } CERT_CHAIN_PARA_NO_EXTRA_FIELDS, *PCERT_CHAIN_PARA_NO_EXTRA_FIELDS;
1047
1048 typedef struct _CERT_CHAIN_PARA_EXTRA_FIELDS {
1049     DWORD            cbSize;
1050     CERT_USAGE_MATCH RequestedUsage;
1051     CERT_USAGE_MATCH RequestedIssuancePolicy;
1052     DWORD            dwUrlRetrievalTimeout;
1053     BOOL             fCheckRevocationFreshnessTime;
1054     DWORD            dwRevocationFreshnessTime;
1055 } CERT_CHAIN_PARA_EXTRA_FIELDS, *PCERT_CHAIN_PARA_EXTRA_FIELDS;
1056
1057 BOOL WINAPI CertGetCertificateChain(HCERTCHAINENGINE hChainEngine,
1058  PCCERT_CONTEXT pCertContext, LPFILETIME pTime, HCERTSTORE hAdditionalStore,
1059  PCERT_CHAIN_PARA pChainPara, DWORD dwFlags, LPVOID pvReserved,
1060  PCCERT_CHAIN_CONTEXT* ppChainContext)
1061 {
1062     BOOL ret;
1063     PCertificateChain chain = NULL;
1064
1065     TRACE("(%p, %p, %p, %p, %p, %08x, %p, %p)\n", hChainEngine, pCertContext,
1066      pTime, hAdditionalStore, pChainPara, dwFlags, pvReserved, ppChainContext);
1067
1068     if (ppChainContext)
1069         *ppChainContext = NULL;
1070     if (!pChainPara)
1071     {
1072         SetLastError(E_INVALIDARG);
1073         return FALSE;
1074     }
1075     if (!pCertContext->pCertInfo->SignatureAlgorithm.pszObjId)
1076     {
1077         SetLastError(ERROR_INVALID_DATA);
1078         return FALSE;
1079     }
1080     if (!hChainEngine)
1081         hChainEngine = CRYPT_GetDefaultChainEngine();
1082     /* FIXME: what about HCCE_LOCAL_MACHINE? */
1083     /* FIXME: pChainPara is for now ignored */
1084     ret = CRYPT_BuildCandidateChainFromCert(hChainEngine, pCertContext, pTime,
1085      hAdditionalStore, &chain);
1086     if (ret)
1087     {
1088         PCertificateChain alternate = NULL;
1089
1090         do {
1091             alternate = CRYPT_BuildAlternateContextFromChain(hChainEngine,
1092              pTime, hAdditionalStore, chain);
1093
1094             /* Alternate contexts are added as "lower quality" contexts of
1095              * chain, to avoid loops in alternate chain creation.
1096              * The highest-quality chain is chosen at the end.
1097              */
1098             if (alternate)
1099                 ret = CRYPT_AddAlternateChainToChain(chain, alternate);
1100         } while (ret && alternate);
1101         chain = CRYPT_ChooseHighestQualityChain(chain);
1102         if (!(dwFlags & CERT_CHAIN_RETURN_LOWER_QUALITY_CONTEXTS))
1103         {
1104             CRYPT_FreeLowerQualityChains(chain);
1105             chain->context.cLowerQualityChainContext = 0;
1106             chain->context.rgpLowerQualityChainContext = NULL;
1107         }
1108         if (ppChainContext)
1109             *ppChainContext = (PCCERT_CHAIN_CONTEXT)chain;
1110         else
1111             CertFreeCertificateChain((PCCERT_CHAIN_CONTEXT)chain);
1112     }
1113     TRACE("returning %d\n", ret);
1114     return ret;
1115 }
1116
1117 PCCERT_CHAIN_CONTEXT WINAPI CertDuplicateCertificateChain(
1118  PCCERT_CHAIN_CONTEXT pChainContext)
1119 {
1120     PCertificateChain chain = (PCertificateChain)pChainContext;
1121
1122     TRACE("(%p)\n", pChainContext);
1123
1124     if (chain)
1125         InterlockedIncrement(&chain->ref);
1126     return pChainContext;
1127 }
1128
1129 VOID WINAPI CertFreeCertificateChain(PCCERT_CHAIN_CONTEXT pChainContext)
1130 {
1131     PCertificateChain chain = (PCertificateChain)pChainContext;
1132
1133     TRACE("(%p)\n", pChainContext);
1134
1135     if (chain)
1136     {
1137         if (InterlockedDecrement(&chain->ref) == 0)
1138             CRYPT_FreeChainContext(chain);
1139     }
1140 }
1141
1142 static void find_element_with_error(PCCERT_CHAIN_CONTEXT chain, DWORD error,
1143  LONG *iChain, LONG *iElement)
1144 {
1145     DWORD i, j;
1146
1147     for (i = 0; i < chain->cChain; i++)
1148         for (j = 0; j < chain->rgpChain[i]->cElement; j++)
1149             if (chain->rgpChain[i]->rgpElement[j]->TrustStatus.dwErrorStatus &
1150              error)
1151             {
1152                 *iChain = i;
1153                 *iElement = j;
1154                 return;
1155             }
1156 }
1157
1158 static BOOL WINAPI verify_base_policy(LPCSTR szPolicyOID,
1159  PCCERT_CHAIN_CONTEXT pChainContext, PCERT_CHAIN_POLICY_PARA pPolicyPara,
1160  PCERT_CHAIN_POLICY_STATUS pPolicyStatus)
1161 {
1162     pPolicyStatus->lChainIndex = pPolicyStatus->lElementIndex = -1;
1163     if (pChainContext->TrustStatus.dwErrorStatus &
1164      CERT_TRUST_IS_NOT_SIGNATURE_VALID)
1165     {
1166         pPolicyStatus->dwError = TRUST_E_CERT_SIGNATURE;
1167         find_element_with_error(pChainContext,
1168          CERT_TRUST_IS_NOT_SIGNATURE_VALID, &pPolicyStatus->lChainIndex,
1169          &pPolicyStatus->lElementIndex);
1170     }
1171     else if (pChainContext->TrustStatus.dwErrorStatus &
1172      CERT_TRUST_IS_UNTRUSTED_ROOT)
1173     {
1174         pPolicyStatus->dwError = CERT_E_UNTRUSTEDROOT;
1175         find_element_with_error(pChainContext,
1176          CERT_TRUST_IS_UNTRUSTED_ROOT, &pPolicyStatus->lChainIndex,
1177          &pPolicyStatus->lElementIndex);
1178     }
1179     else if (pChainContext->TrustStatus.dwErrorStatus & CERT_TRUST_IS_CYCLIC)
1180     {
1181         pPolicyStatus->dwError = CERT_E_CHAINING;
1182         find_element_with_error(pChainContext, CERT_TRUST_IS_CYCLIC,
1183          &pPolicyStatus->lChainIndex, &pPolicyStatus->lElementIndex);
1184         /* For a cyclic chain, which element is a cycle isn't meaningful */
1185         pPolicyStatus->lElementIndex = -1;
1186     }
1187     return TRUE;
1188 }
1189
1190 static BYTE msTestPubKey1[] = {
1191 0x30,0x47,0x02,0x40,0x81,0x55,0x22,0xb9,0x8a,0xa4,0x6f,0xed,0xd6,0xe7,0xd9,
1192 0x66,0x0f,0x55,0xbc,0xd7,0xcd,0xd5,0xbc,0x4e,0x40,0x02,0x21,0xa2,0xb1,0xf7,
1193 0x87,0x30,0x85,0x5e,0xd2,0xf2,0x44,0xb9,0xdc,0x9b,0x75,0xb6,0xfb,0x46,0x5f,
1194 0x42,0xb6,0x9d,0x23,0x36,0x0b,0xde,0x54,0x0f,0xcd,0xbd,0x1f,0x99,0x2a,0x10,
1195 0x58,0x11,0xcb,0x40,0xcb,0xb5,0xa7,0x41,0x02,0x03,0x01,0x00,0x01 };
1196 static BYTE msTestPubKey2[] = {
1197 0x30,0x48,0x02,0x41,0x00,0x81,0x55,0x22,0xb9,0x8a,0xa4,0x6f,0xed,0xd6,0xe7,
1198 0xd9,0x66,0x0f,0x55,0xbc,0xd7,0xcd,0xd5,0xbc,0x4e,0x40,0x02,0x21,0xa2,0xb1,
1199 0xf7,0x87,0x30,0x85,0x5e,0xd2,0xf2,0x44,0xb9,0xdc,0x9b,0x75,0xb6,0xfb,0x46,
1200 0x5f,0x42,0xb6,0x9d,0x23,0x36,0x0b,0xde,0x54,0x0f,0xcd,0xbd,0x1f,0x99,0x2a,
1201 0x10,0x58,0x11,0xcb,0x40,0xcb,0xb5,0xa7,0x41,0x02,0x03,0x01,0x00,0x01 };
1202 static BYTE msTestPubKey3[] = {
1203 0x30,0x47,0x02,0x40,0x9c,0x50,0x05,0x1d,0xe2,0x0e,0x4c,0x53,0xd8,0xd9,0xb5,
1204 0xe5,0xfd,0xe9,0xe3,0xad,0x83,0x4b,0x80,0x08,0xd9,0xdc,0xe8,0xe8,0x35,0xf8,
1205 0x11,0xf1,0xe9,0x9b,0x03,0x7a,0x65,0x64,0x76,0x35,0xce,0x38,0x2c,0xf2,0xb6,
1206 0x71,0x9e,0x06,0xd9,0xbf,0xbb,0x31,0x69,0xa3,0xf6,0x30,0xa0,0x78,0x7b,0x18,
1207 0xdd,0x50,0x4d,0x79,0x1e,0xeb,0x61,0xc1,0x02,0x03,0x01,0x00,0x01 };
1208
1209 static BOOL WINAPI verify_authenticode_policy(LPCSTR szPolicyOID,
1210  PCCERT_CHAIN_CONTEXT pChainContext, PCERT_CHAIN_POLICY_PARA pPolicyPara,
1211  PCERT_CHAIN_POLICY_STATUS pPolicyStatus)
1212 {
1213     BOOL ret = verify_base_policy(szPolicyOID, pChainContext, pPolicyPara,
1214      pPolicyStatus);
1215
1216     if (ret && pPolicyStatus->dwError == CERT_E_UNTRUSTEDROOT)
1217     {
1218         CERT_PUBLIC_KEY_INFO msPubKey = { { 0 } };
1219         BOOL isMSTestRoot = FALSE;
1220         PCCERT_CONTEXT failingCert =
1221          pChainContext->rgpChain[pPolicyStatus->lChainIndex]->
1222          rgpElement[pPolicyStatus->lElementIndex]->pCertContext;
1223         DWORD i;
1224         CRYPT_DATA_BLOB keyBlobs[] = {
1225          { sizeof(msTestPubKey1), msTestPubKey1 },
1226          { sizeof(msTestPubKey2), msTestPubKey2 },
1227          { sizeof(msTestPubKey3), msTestPubKey3 },
1228         };
1229
1230         /* Check whether the root is an MS test root */
1231         for (i = 0; !isMSTestRoot && i < sizeof(keyBlobs) / sizeof(keyBlobs[0]);
1232          i++)
1233         {
1234             msPubKey.PublicKey.cbData = keyBlobs[i].cbData;
1235             msPubKey.PublicKey.pbData = keyBlobs[i].pbData;
1236             if (CertComparePublicKeyInfo(
1237              X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
1238              &failingCert->pCertInfo->SubjectPublicKeyInfo, &msPubKey))
1239                 isMSTestRoot = TRUE;
1240         }
1241         if (isMSTestRoot)
1242             pPolicyStatus->dwError = CERT_E_UNTRUSTEDTESTROOT;
1243     }
1244     return ret;
1245 }
1246
1247 static BOOL WINAPI verify_basic_constraints_policy(LPCSTR szPolicyOID,
1248  PCCERT_CHAIN_CONTEXT pChainContext, PCERT_CHAIN_POLICY_PARA pPolicyPara,
1249  PCERT_CHAIN_POLICY_STATUS pPolicyStatus)
1250 {
1251     pPolicyStatus->lChainIndex = pPolicyStatus->lElementIndex = -1;
1252     if (pChainContext->TrustStatus.dwErrorStatus &
1253      CERT_TRUST_INVALID_BASIC_CONSTRAINTS)
1254     {
1255         pPolicyStatus->dwError = TRUST_E_BASIC_CONSTRAINTS;
1256         find_element_with_error(pChainContext,
1257          CERT_TRUST_INVALID_BASIC_CONSTRAINTS, &pPolicyStatus->lChainIndex,
1258          &pPolicyStatus->lElementIndex);
1259     }
1260     return TRUE;
1261 }
1262
1263 typedef BOOL (WINAPI *CertVerifyCertificateChainPolicyFunc)(LPCSTR szPolicyOID,
1264  PCCERT_CHAIN_CONTEXT pChainContext, PCERT_CHAIN_POLICY_PARA pPolicyPara,
1265  PCERT_CHAIN_POLICY_STATUS pPolicyStatus);
1266
1267 BOOL WINAPI CertVerifyCertificateChainPolicy(LPCSTR szPolicyOID,
1268  PCCERT_CHAIN_CONTEXT pChainContext, PCERT_CHAIN_POLICY_PARA pPolicyPara,
1269  PCERT_CHAIN_POLICY_STATUS pPolicyStatus)
1270 {
1271     static HCRYPTOIDFUNCSET set = NULL;
1272     BOOL ret = FALSE;
1273     CertVerifyCertificateChainPolicyFunc verifyPolicy = NULL;
1274     HCRYPTOIDFUNCADDR hFunc = NULL;
1275
1276     TRACE("(%s, %p, %p, %p)\n", debugstr_a(szPolicyOID), pChainContext,
1277      pPolicyPara, pPolicyStatus);
1278
1279     if (!HIWORD(szPolicyOID))
1280     {
1281         switch (LOWORD(szPolicyOID))
1282         {
1283         case (int)CERT_CHAIN_POLICY_BASE:
1284             verifyPolicy = verify_base_policy;
1285             break;
1286         case (int)CERT_CHAIN_POLICY_AUTHENTICODE:
1287             verifyPolicy = verify_authenticode_policy;
1288             break;
1289         case (int)CERT_CHAIN_POLICY_BASIC_CONSTRAINTS:
1290             verifyPolicy = verify_basic_constraints_policy;
1291             break;
1292         default:
1293             FIXME("unimplemented for %d\n", LOWORD(szPolicyOID));
1294         }
1295     }
1296     if (!verifyPolicy)
1297     {
1298         if (!set)
1299             set = CryptInitOIDFunctionSet(
1300              CRYPT_OID_VERIFY_CERTIFICATE_CHAIN_POLICY_FUNC, 0);
1301         CryptGetOIDFunctionAddress(set, X509_ASN_ENCODING, szPolicyOID, 0,
1302          (void **)&verifyPolicy, hFunc);
1303     }
1304     if (verifyPolicy)
1305         ret = verifyPolicy(szPolicyOID, pChainContext, pPolicyPara,
1306          pPolicyStatus);
1307     if (hFunc)
1308         CryptFreeOIDFunctionAddress(hFunc, 0);
1309     return ret;
1310 }