cert_verify_proc_nss.cc revision eb525c5499e34cc9c4b825d6d9e75bb07cc06ace 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "net/cert/cert_verify_proc_nss.h"
6
7#include <string>
8#include <vector>
9
10#include <cert.h>
11#include <nss.h>
12#include <prerror.h>
13#include <secerr.h>
14#include <sechash.h>
15#include <sslerr.h>
16
17#include "base/logging.h"
18#include "crypto/nss_util.h"
19#include "crypto/scoped_nss_types.h"
20#include "crypto/sha2.h"
21#include "net/base/net_errors.h"
22#include "net/cert/asn1_util.h"
23#include "net/cert/cert_status_flags.h"
24#include "net/cert/cert_verifier.h"
25#include "net/cert/cert_verify_result.h"
26#include "net/cert/crl_set.h"
27#include "net/cert/ev_root_ca_metadata.h"
28#include "net/cert/x509_certificate.h"
29#include "net/cert/x509_util_nss.h"
30
31#if defined(OS_IOS)
32#include <CommonCrypto/CommonDigest.h>
33#include "net/cert/x509_util_ios.h"
34#endif  // defined(OS_IOS)
35
36#define NSS_VERSION_NUM (NSS_VMAJOR * 10000 + NSS_VMINOR * 100 + NSS_VPATCH)
37#if NSS_VERSION_NUM < 31305
38// Added in NSS 3.13.5.
39#define SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED -8016
40#endif
41
42#if NSS_VERSION_NUM < 31402
43// Added in NSS 3.14.2.
44#define cert_pi_useOnlyTrustAnchors static_cast<CERTValParamInType>(14)
45#endif
46
47namespace net {
48
49namespace {
50
51typedef scoped_ptr_malloc<
52    CERTCertificatePolicies,
53    crypto::NSSDestroyer<CERTCertificatePolicies,
54                         CERT_DestroyCertificatePoliciesExtension> >
55    ScopedCERTCertificatePolicies;
56
57typedef scoped_ptr_malloc<
58    CERTCertList,
59    crypto::NSSDestroyer<CERTCertList, CERT_DestroyCertList> >
60    ScopedCERTCertList;
61
62// ScopedCERTValOutParam manages destruction of values in the CERTValOutParam
63// array that cvout points to.  cvout must be initialized as passed to
64// CERT_PKIXVerifyCert, so that the array must be terminated with
65// cert_po_end type.
66// When it goes out of scope, it destroys values of cert_po_trustAnchor
67// and cert_po_certList types, but doesn't release the array itself.
68class ScopedCERTValOutParam {
69 public:
70  explicit ScopedCERTValOutParam(CERTValOutParam* cvout)
71      : cvout_(cvout) {}
72
73  ~ScopedCERTValOutParam() {
74    if (cvout_ == NULL)
75      return;
76    for (CERTValOutParam *p = cvout_; p->type != cert_po_end; p++) {
77      switch (p->type) {
78        case cert_po_trustAnchor:
79          if (p->value.pointer.cert) {
80            CERT_DestroyCertificate(p->value.pointer.cert);
81            p->value.pointer.cert = NULL;
82          }
83          break;
84        case cert_po_certList:
85          if (p->value.pointer.chain) {
86            CERT_DestroyCertList(p->value.pointer.chain);
87            p->value.pointer.chain = NULL;
88          }
89          break;
90        default:
91          break;
92      }
93    }
94  }
95
96 private:
97  CERTValOutParam* cvout_;
98
99  DISALLOW_COPY_AND_ASSIGN(ScopedCERTValOutParam);
100};
101
102// Map PORT_GetError() return values to our network error codes.
103int MapSecurityError(int err) {
104  switch (err) {
105    case PR_DIRECTORY_LOOKUP_ERROR:  // DNS lookup error.
106      return ERR_NAME_NOT_RESOLVED;
107    case SEC_ERROR_INVALID_ARGS:
108      return ERR_INVALID_ARGUMENT;
109    case SSL_ERROR_BAD_CERT_DOMAIN:
110      return ERR_CERT_COMMON_NAME_INVALID;
111    case SEC_ERROR_INVALID_TIME:
112    case SEC_ERROR_EXPIRED_CERTIFICATE:
113    case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
114      return ERR_CERT_DATE_INVALID;
115    case SEC_ERROR_UNKNOWN_ISSUER:
116    case SEC_ERROR_UNTRUSTED_ISSUER:
117    case SEC_ERROR_CA_CERT_INVALID:
118      return ERR_CERT_AUTHORITY_INVALID;
119    // TODO(port): map ERR_CERT_NO_REVOCATION_MECHANISM.
120    case SEC_ERROR_OCSP_BAD_HTTP_RESPONSE:
121    case SEC_ERROR_OCSP_SERVER_ERROR:
122      return ERR_CERT_UNABLE_TO_CHECK_REVOCATION;
123    case SEC_ERROR_REVOKED_CERTIFICATE:
124    case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
125      return ERR_CERT_REVOKED;
126    case SEC_ERROR_BAD_DER:
127    case SEC_ERROR_BAD_SIGNATURE:
128    case SEC_ERROR_CERT_NOT_VALID:
129    // TODO(port): add an ERR_CERT_WRONG_USAGE error code.
130    case SEC_ERROR_CERT_USAGES_INVALID:
131    case SEC_ERROR_INADEQUATE_KEY_USAGE:  // Key usage.
132    case SEC_ERROR_INADEQUATE_CERT_TYPE:  // Extended key usage and whether
133                                          // the certificate is a CA.
134    case SEC_ERROR_POLICY_VALIDATION_FAILED:
135    case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
136    case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
137    case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
138    case SEC_ERROR_EXTENSION_VALUE_INVALID:
139      return ERR_CERT_INVALID;
140    case SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED:
141      return ERR_CERT_WEAK_SIGNATURE_ALGORITHM;
142    default:
143      LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
144      return ERR_FAILED;
145  }
146}
147
148// Map PORT_GetError() return values to our cert status flags.
149CertStatus MapCertErrorToCertStatus(int err) {
150  int net_error = MapSecurityError(err);
151  return MapNetErrorToCertStatus(net_error);
152}
153
154// Saves some information about the certificate chain cert_list in
155// *verify_result.  The caller MUST initialize *verify_result before calling
156// this function.
157// Note that cert_list[0] is the end entity certificate.
158void GetCertChainInfo(CERTCertList* cert_list,
159                      CERTCertificate* root_cert,
160                      CertVerifyResult* verify_result) {
161  // NOTE: Using a NSS library before 3.12.3.1 will crash below.  To see the
162  // NSS version currently in use:
163  // 1. use ldd on the chrome executable for NSS's location (ie. libnss3.so*)
164  // 2. use ident libnss3.so* for the library's version
165  DCHECK(cert_list);
166
167  CERTCertificate* verified_cert = NULL;
168  std::vector<CERTCertificate*> verified_chain;
169  int i = 0;
170  for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
171       !CERT_LIST_END(node, cert_list);
172       node = CERT_LIST_NEXT(node), ++i) {
173    if (i == 0) {
174      verified_cert = node->cert;
175    } else {
176      // Because of an NSS bug, CERT_PKIXVerifyCert may chain a self-signed
177      // certificate of a root CA to another certificate of the same root CA
178      // key.  Detect that error and ignore the root CA certificate.
179      // See https://bugzilla.mozilla.org/show_bug.cgi?id=721288.
180      if (node->cert->isRoot) {
181        // NOTE: isRoot doesn't mean the certificate is a trust anchor.  It
182        // means the certificate is self-signed.  Here we assume isRoot only
183        // implies the certificate is self-issued.
184        CERTCertListNode* next_node = CERT_LIST_NEXT(node);
185        CERTCertificate* next_cert;
186        if (!CERT_LIST_END(next_node, cert_list)) {
187          next_cert = next_node->cert;
188        } else {
189          next_cert = root_cert;
190        }
191        // Test that |node->cert| is actually a self-signed certificate
192        // whose key is equal to |next_cert|, and not a self-issued
193        // certificate signed by another key of the same CA.
194        if (next_cert && SECITEM_ItemsAreEqual(&node->cert->derPublicKey,
195                                               &next_cert->derPublicKey)) {
196          continue;
197        }
198      }
199      verified_chain.push_back(node->cert);
200    }
201
202    SECAlgorithmID& signature = node->cert->signature;
203    SECOidTag oid_tag = SECOID_FindOIDTag(&signature.algorithm);
204    switch (oid_tag) {
205      case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
206        verify_result->has_md5 = true;
207        break;
208      case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
209        verify_result->has_md2 = true;
210        break;
211      case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
212        verify_result->has_md4 = true;
213        break;
214      default:
215        break;
216    }
217  }
218
219  if (root_cert)
220    verified_chain.push_back(root_cert);
221#if defined(OS_IOS)
222  verify_result->verified_cert =
223      x509_util_ios::CreateCertFromNSSHandles(verified_cert, verified_chain);
224#else
225  verify_result->verified_cert =
226      X509Certificate::CreateFromHandle(verified_cert, verified_chain);
227#endif  // defined(OS_IOS)
228}
229
230// IsKnownRoot returns true if the given certificate is one that we believe
231// is a standard (as opposed to user-installed) root.
232bool IsKnownRoot(CERTCertificate* root) {
233  if (!root || !root->slot)
234    return false;
235
236  // This magic name is taken from
237  // http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/security/nss/lib/ckfw/builtins/constants.c&rev=1.13&mark=86,89#79
238  return 0 == strcmp(PK11_GetSlotName(root->slot),
239                     "NSS Builtin Objects");
240}
241
242// Returns true if the given certificate is one of the additional trust anchors.
243bool IsAdditionalTrustAnchor(CERTCertList* additional_trust_anchors,
244                             CERTCertificate* root) {
245  if (!additional_trust_anchors || !root)
246    return false;
247  for (CERTCertListNode* node = CERT_LIST_HEAD(additional_trust_anchors);
248       !CERT_LIST_END(node, additional_trust_anchors);
249       node = CERT_LIST_NEXT(node)) {
250    if (CERT_CompareCerts(node->cert, root))
251      return true;
252  }
253  return false;
254}
255
256enum CRLSetResult {
257  kCRLSetRevoked,
258  kCRLSetOk,
259  kCRLSetError,
260};
261
262// CheckRevocationWithCRLSet attempts to check each element of |cert_list|
263// against |crl_set|. It returns:
264//   kCRLSetRevoked: if any element of the chain is known to have been revoked.
265//   kCRLSetError: if an error occurs in processing.
266//   kCRLSetOk: if no element in the chain is known to have been revoked.
267CRLSetResult CheckRevocationWithCRLSet(CERTCertList* cert_list,
268                                       CERTCertificate* root,
269                                       CRLSet* crl_set) {
270  std::vector<CERTCertificate*> certs;
271
272  if (cert_list) {
273    for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
274         !CERT_LIST_END(node, cert_list);
275         node = CERT_LIST_NEXT(node)) {
276      certs.push_back(node->cert);
277    }
278  }
279  if (root)
280    certs.push_back(root);
281
282  // We iterate from the root certificate down to the leaf, keeping track of
283  // the issuer's SPKI at each step.
284  std::string issuer_spki_hash;
285  for (std::vector<CERTCertificate*>::reverse_iterator i = certs.rbegin();
286       i != certs.rend(); ++i) {
287    CERTCertificate* cert = *i;
288
289    base::StringPiece der(reinterpret_cast<char*>(cert->derCert.data),
290                          cert->derCert.len);
291
292    base::StringPiece spki;
293    if (!asn1::ExtractSPKIFromDERCert(der, &spki)) {
294      NOTREACHED();
295      return kCRLSetError;
296    }
297    const std::string spki_hash = crypto::SHA256HashString(spki);
298
299    base::StringPiece serial_number = base::StringPiece(
300        reinterpret_cast<char*>(cert->serialNumber.data),
301        cert->serialNumber.len);
302
303    CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
304
305    if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
306      result = crl_set->CheckSerial(serial_number, issuer_spki_hash);
307
308    issuer_spki_hash = spki_hash;
309
310    switch (result) {
311      case CRLSet::REVOKED:
312        return kCRLSetRevoked;
313      case CRLSet::UNKNOWN:
314      case CRLSet::GOOD:
315        continue;
316      default:
317        NOTREACHED();
318        return kCRLSetError;
319    }
320  }
321
322  return kCRLSetOk;
323}
324
325// Forward declarations.
326SECStatus RetryPKIXVerifyCertWithWorkarounds(
327    CERTCertificate* cert_handle, int num_policy_oids,
328    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
329    CERTValOutParam* cvout);
330SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle);
331
332// Call CERT_PKIXVerifyCert for the cert_handle.
333// Verification results are stored in an array of CERTValOutParam.
334// If policy_oids is not NULL and num_policy_oids is positive, policies
335// are also checked.
336// additional_trust_anchors is an optional list of certificates that can be
337// trusted as anchors when building a certificate chain.
338// Caller must initialize cvout before calling this function.
339SECStatus PKIXVerifyCert(CERTCertificate* cert_handle,
340                         bool check_revocation,
341                         bool cert_io_enabled,
342                         const SECOidTag* policy_oids,
343                         int num_policy_oids,
344                         CERTCertList* additional_trust_anchors,
345                         CERTValOutParam* cvout) {
346  bool use_crl = check_revocation;
347  bool use_ocsp = check_revocation;
348
349  // These CAs have multiple keys, which trigger two bugs in NSS's CRL code.
350  // 1. NSS may use one key to verify a CRL signed with another key,
351  //    incorrectly concluding that the CRL's signature is invalid.
352  //    Hopefully this bug will be fixed in NSS 3.12.9.
353  // 2. NSS considers all certificates issued by the CA as revoked when it
354  //    receives a CRL with an invalid signature.  This overly strict policy
355  //    has been relaxed in NSS 3.12.7.  See
356  //    https://bugzilla.mozilla.org/show_bug.cgi?id=562542.
357  // So we have to turn off CRL checking for these CAs.  See
358  // http://crbug.com/55695.
359  static const char* const kMultipleKeyCA[] = {
360    "CN=Microsoft Secure Server Authority,"
361    "DC=redmond,DC=corp,DC=microsoft,DC=com",
362    "CN=Microsoft Secure Server Authority",
363  };
364
365  if (!NSS_VersionCheck("3.12.7")) {
366    for (size_t i = 0; i < arraysize(kMultipleKeyCA); ++i) {
367      if (strcmp(cert_handle->issuerName, kMultipleKeyCA[i]) == 0) {
368        use_crl = false;
369        break;
370      }
371    }
372  }
373
374  PRUint64 revocation_method_flags =
375      CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
376      CERT_REV_M_ALLOW_NETWORK_FETCHING |
377      CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
378      CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
379      CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
380  PRUint64 revocation_method_independent_flags =
381      CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
382  if (check_revocation && policy_oids && num_policy_oids > 0) {
383    // EV verification requires revocation checking.  Consider the certificate
384    // revoked if we don't have revocation info.
385    // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
386    // verification or we want strict revocation flags.
387    revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
388    revocation_method_independent_flags |=
389        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
390  } else {
391    revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
392    revocation_method_independent_flags |=
393        CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
394  }
395  PRUint64 method_flags[2];
396  method_flags[cert_revocation_method_crl] = revocation_method_flags;
397  method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
398
399  if (use_crl) {
400    method_flags[cert_revocation_method_crl] |=
401        CERT_REV_M_TEST_USING_THIS_METHOD;
402  }
403  if (use_ocsp) {
404    method_flags[cert_revocation_method_ocsp] |=
405        CERT_REV_M_TEST_USING_THIS_METHOD;
406  }
407
408  CERTRevocationMethodIndex preferred_revocation_methods[1];
409  if (use_ocsp) {
410    preferred_revocation_methods[0] = cert_revocation_method_ocsp;
411  } else {
412    preferred_revocation_methods[0] = cert_revocation_method_crl;
413  }
414
415  CERTRevocationFlags revocation_flags;
416  revocation_flags.leafTests.number_of_defined_methods =
417      arraysize(method_flags);
418  revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
419  revocation_flags.leafTests.number_of_preferred_methods =
420      arraysize(preferred_revocation_methods);
421  revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
422  revocation_flags.leafTests.cert_rev_method_independent_flags =
423      revocation_method_independent_flags;
424
425  revocation_flags.chainTests.number_of_defined_methods =
426      arraysize(method_flags);
427  revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
428  revocation_flags.chainTests.number_of_preferred_methods =
429      arraysize(preferred_revocation_methods);
430  revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
431  revocation_flags.chainTests.cert_rev_method_independent_flags =
432      revocation_method_independent_flags;
433
434
435  std::vector<CERTValInParam> cvin;
436  cvin.reserve(7);
437  CERTValInParam in_param;
438  in_param.type = cert_pi_revocationFlags;
439  in_param.value.pointer.revocation = &revocation_flags;
440  cvin.push_back(in_param);
441  if (policy_oids && num_policy_oids > 0) {
442    in_param.type = cert_pi_policyOID;
443    in_param.value.arraySize = num_policy_oids;
444    in_param.value.array.oids = policy_oids;
445    cvin.push_back(in_param);
446  }
447  if (additional_trust_anchors) {
448    in_param.type = cert_pi_trustAnchors;
449    in_param.value.pointer.chain = additional_trust_anchors;
450    cvin.push_back(in_param);
451    in_param.type = cert_pi_useOnlyTrustAnchors;
452    in_param.value.scalar.b = PR_FALSE;
453    cvin.push_back(in_param);
454  }
455  in_param.type = cert_pi_end;
456  cvin.push_back(in_param);
457
458  SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
459                                     &cvin[0], cvout, NULL);
460  if (rv != SECSuccess) {
461    rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
462                                            cert_io_enabled, &cvin, cvout);
463  }
464  return rv;
465}
466
467// PKIXVerifyCert calls this function to work around some bugs in
468// CERT_PKIXVerifyCert.  All the arguments of this function are either the
469// arguments or local variables of PKIXVerifyCert.
470SECStatus RetryPKIXVerifyCertWithWorkarounds(
471    CERTCertificate* cert_handle, int num_policy_oids,
472    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
473    CERTValOutParam* cvout) {
474  // We call this function when the first CERT_PKIXVerifyCert call in
475  // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
476  SECStatus rv = SECFailure;
477  int nss_error = PORT_GetError();
478  CERTValInParam in_param;
479
480  // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
481  // CA certificate, so we retry with cert_pi_useAIACertFetch.
482  // cert_pi_useAIACertFetch has several bugs in its error handling and
483  // error reporting (NSS bug 528743), so we don't use it by default.
484  // Note: When building a certificate chain, CERT_PKIXVerifyCert may
485  // incorrectly pick a CA certificate with the same subject name as the
486  // missing intermediate CA certificate, and  fail with the
487  // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
488  // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
489  if (cert_io_enabled &&
490      (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
491       nss_error == SEC_ERROR_BAD_SIGNATURE)) {
492    DCHECK_EQ(cvin->back().type,  cert_pi_end);
493    cvin->pop_back();
494    in_param.type = cert_pi_useAIACertFetch;
495    in_param.value.scalar.b = PR_TRUE;
496    cvin->push_back(in_param);
497    in_param.type = cert_pi_end;
498    cvin->push_back(in_param);
499    rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
500                             &(*cvin)[0], cvout, NULL);
501    if (rv == SECSuccess)
502      return rv;
503    int new_nss_error = PORT_GetError();
504    if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
505        new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
506        new_nss_error == SEC_ERROR_BAD_INFO_ACCESS_LOCATION ||
507        new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
508        new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
509        !IS_SEC_ERROR(new_nss_error)) {
510      // Use the original error code because of cert_pi_useAIACertFetch's
511      // bad error reporting.
512      PORT_SetError(nss_error);
513      return rv;
514    }
515    nss_error = new_nss_error;
516  }
517
518  // If an intermediate CA certificate has requireExplicitPolicy in its
519  // policyConstraints extension, CERT_PKIXVerifyCert fails with
520  // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
521  // certificate policy (NSS bug 552775).  So we retry with the certificate
522  // policy found in the server certificate.
523  if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
524      num_policy_oids == 0) {
525    SECOidTag policy = GetFirstCertPolicy(cert_handle);
526    if (policy != SEC_OID_UNKNOWN) {
527      DCHECK_EQ(cvin->back().type,  cert_pi_end);
528      cvin->pop_back();
529      in_param.type = cert_pi_policyOID;
530      in_param.value.arraySize = 1;
531      in_param.value.array.oids = &policy;
532      cvin->push_back(in_param);
533      in_param.type = cert_pi_end;
534      cvin->push_back(in_param);
535      rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
536                               &(*cvin)[0], cvout, NULL);
537      if (rv != SECSuccess) {
538        // Use the original error code.
539        PORT_SetError(nss_error);
540      }
541    }
542  }
543
544  return rv;
545}
546
547// Decodes the certificatePolicies extension of the certificate.  Returns
548// NULL if the certificate doesn't have the extension or the extension can't
549// be decoded.  The returned value must be freed with a
550// CERT_DestroyCertificatePoliciesExtension call.
551CERTCertificatePolicies* DecodeCertPolicies(
552    CERTCertificate* cert_handle) {
553  SECItem policy_ext;
554  SECStatus rv = CERT_FindCertExtension(cert_handle,
555                                        SEC_OID_X509_CERTIFICATE_POLICIES,
556                                        &policy_ext);
557  if (rv != SECSuccess)
558    return NULL;
559  CERTCertificatePolicies* policies =
560      CERT_DecodeCertificatePoliciesExtension(&policy_ext);
561  SECITEM_FreeItem(&policy_ext, PR_FALSE);
562  return policies;
563}
564
565// Returns the OID tag for the first certificate policy in the certificate's
566// certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
567// has no certificate policy.
568SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle) {
569  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
570  if (!policies.get())
571    return SEC_OID_UNKNOWN;
572
573  CERTPolicyInfo* policy_info = policies->policyInfos[0];
574  if (!policy_info)
575    return SEC_OID_UNKNOWN;
576  if (policy_info->oid != SEC_OID_UNKNOWN)
577    return policy_info->oid;
578
579  // The certificate policy is unknown to NSS.  We need to create a dynamic
580  // OID tag for the policy.
581  SECOidData od;
582  od.oid.len = policy_info->policyID.len;
583  od.oid.data = policy_info->policyID.data;
584  od.offset = SEC_OID_UNKNOWN;
585  // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
586  // default description here.  The description doesn't need to be unique for
587  // each OID.
588  od.desc = "a certificate policy";
589  od.mechanism = CKM_INVALID_MECHANISM;
590  od.supportedExtension = INVALID_CERT_EXTENSION;
591  return SECOID_AddEntry(&od);
592}
593
594HashValue CertPublicKeyHashSHA1(CERTCertificate* cert) {
595  HashValue hash(HASH_VALUE_SHA1);
596#if defined(OS_IOS)
597  CC_SHA1(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
598#else
599  SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data(),
600                              cert->derPublicKey.data, cert->derPublicKey.len);
601  DCHECK_EQ(SECSuccess, rv);
602#endif
603  return hash;
604}
605
606HashValue CertPublicKeyHashSHA256(CERTCertificate* cert) {
607  HashValue hash(HASH_VALUE_SHA256);
608#if defined(OS_IOS)
609  CC_SHA256(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
610#else
611  SECStatus rv = HASH_HashBuf(HASH_AlgSHA256, hash.data(),
612                              cert->derPublicKey.data, cert->derPublicKey.len);
613  DCHECK_EQ(rv, SECSuccess);
614#endif
615  return hash;
616}
617
618void AppendPublicKeyHashes(CERTCertList* cert_list,
619                           CERTCertificate* root_cert,
620                           HashValueVector* hashes) {
621  for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
622       !CERT_LIST_END(node, cert_list);
623       node = CERT_LIST_NEXT(node)) {
624    hashes->push_back(CertPublicKeyHashSHA1(node->cert));
625    hashes->push_back(CertPublicKeyHashSHA256(node->cert));
626  }
627  if (root_cert) {
628    hashes->push_back(CertPublicKeyHashSHA1(root_cert));
629    hashes->push_back(CertPublicKeyHashSHA256(root_cert));
630  }
631}
632
633// Returns true if |cert_handle| contains a policy OID that is an EV policy
634// OID according to |metadata|, storing the resulting policy OID in
635// |*ev_policy_oid|. A true return is not sufficient to establish that a
636// certificate is EV, but a false return is sufficient to establish the
637// certificate cannot be EV.
638bool IsEVCandidate(EVRootCAMetadata* metadata,
639                   CERTCertificate* cert_handle,
640                   SECOidTag* ev_policy_oid) {
641  DCHECK(cert_handle);
642  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
643  if (!policies.get())
644    return false;
645
646  CERTPolicyInfo** policy_infos = policies->policyInfos;
647  while (*policy_infos != NULL) {
648    CERTPolicyInfo* policy_info = *policy_infos++;
649    // If the Policy OID is unknown, that implicitly means it has not been
650    // registered as an EV policy.
651    if (policy_info->oid == SEC_OID_UNKNOWN)
652      continue;
653    if (metadata->IsEVPolicyOID(policy_info->oid)) {
654      *ev_policy_oid = policy_info->oid;
655      return true;
656    }
657  }
658
659  return false;
660}
661
662// Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
663// and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
664// TODO(wtc): A possible optimization is that we get the trust anchor from
665// the first PKIXVerifyCert call.  We look up the EV policy for the trust
666// anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
667// Otherwise, we pass just that EV policy (as opposed to all the EV policies)
668// to the second PKIXVerifyCert call.
669bool VerifyEV(CERTCertificate* cert_handle,
670              int flags,
671              CRLSet* crl_set,
672              EVRootCAMetadata* metadata,
673              SECOidTag ev_policy_oid,
674              CERTCertList* additional_trust_anchors) {
675  CERTValOutParam cvout[3];
676  int cvout_index = 0;
677  cvout[cvout_index].type = cert_po_certList;
678  cvout[cvout_index].value.pointer.chain = NULL;
679  int cvout_cert_list_index = cvout_index;
680  cvout_index++;
681  cvout[cvout_index].type = cert_po_trustAnchor;
682  cvout[cvout_index].value.pointer.cert = NULL;
683  int cvout_trust_anchor_index = cvout_index;
684  cvout_index++;
685  cvout[cvout_index].type = cert_po_end;
686  ScopedCERTValOutParam scoped_cvout(cvout);
687
688  bool rev_checking_enabled =
689      (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED) ||
690      (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY);
691
692  SECStatus status = PKIXVerifyCert(
693      cert_handle,
694      rev_checking_enabled,
695      flags & CertVerifier::VERIFY_CERT_IO_ENABLED,
696      &ev_policy_oid,
697      1,
698      additional_trust_anchors,
699      cvout);
700  if (status != SECSuccess)
701    return false;
702
703  CERTCertificate* root_ca =
704      cvout[cvout_trust_anchor_index].value.pointer.cert;
705  if (root_ca == NULL)
706    return false;
707
708  // This second PKIXVerifyCert call could have found a different certification
709  // path and one or more of the certificates on this new path, that weren't on
710  // the old path, might have been revoked.
711  if (crl_set) {
712    CRLSetResult crl_set_result = CheckRevocationWithCRLSet(
713        cvout[cvout_cert_list_index].value.pointer.chain,
714        cvout[cvout_trust_anchor_index].value.pointer.cert,
715        crl_set);
716    if (crl_set_result == kCRLSetRevoked)
717      return false;
718  }
719
720#if defined(OS_IOS)
721  SHA1HashValue fingerprint = x509_util_ios::CalculateFingerprintNSS(root_ca);
722#else
723  SHA1HashValue fingerprint =
724      X509Certificate::CalculateFingerprint(root_ca);
725#endif
726  return metadata->HasEVPolicyOID(fingerprint, ev_policy_oid);
727}
728
729CERTCertList* CertificateListToCERTCertList(const CertificateList& list) {
730  CERTCertList* result = CERT_NewCertList();
731  for (size_t i = 0; i < list.size(); ++i) {
732#if defined(OS_IOS)
733    // X509Certificate::os_cert_handle() on iOS is a SecCertificateRef; convert
734    // it to an NSS CERTCertificate.
735    CERTCertificate* cert = x509_util_ios::CreateNSSCertHandleFromOSHandle(
736        list[i]->os_cert_handle());
737#else
738    CERTCertificate* cert = list[i]->os_cert_handle();
739#endif
740    CERT_AddCertToListTail(result, CERT_DupCertificate(cert));
741  }
742  return result;
743}
744
745}  // namespace
746
747CertVerifyProcNSS::CertVerifyProcNSS() {}
748
749CertVerifyProcNSS::~CertVerifyProcNSS() {}
750
751bool CertVerifyProcNSS::SupportsAdditionalTrustAnchors() const {
752  // This requires APIs introduced in 3.14.2.
753  return NSS_VersionCheck("3.14.2");
754}
755
756int CertVerifyProcNSS::VerifyInternal(
757    X509Certificate* cert,
758    const std::string& hostname,
759    int flags,
760    CRLSet* crl_set,
761    const CertificateList& additional_trust_anchors,
762    CertVerifyResult* verify_result) {
763#if defined(OS_IOS)
764  // For iOS, the entire chain must be loaded into NSS's in-memory certificate
765  // store.
766  x509_util_ios::NSSCertChain scoped_chain(cert);
767  CERTCertificate* cert_handle = scoped_chain.cert_handle();
768#else
769  CERTCertificate* cert_handle = cert->os_cert_handle();
770#endif  // defined(OS_IOS)
771
772  // Make sure that the hostname matches with the common name of the cert.
773  SECStatus status = CERT_VerifyCertName(cert_handle, hostname.c_str());
774  if (status != SECSuccess)
775    verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
776
777  // Make sure that the cert is valid now.
778  SECCertTimeValidity validity = CERT_CheckCertValidTimes(
779      cert_handle, PR_Now(), PR_TRUE);
780  if (validity != secCertTimeValid)
781    verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
782
783  CERTValOutParam cvout[3];
784  int cvout_index = 0;
785  cvout[cvout_index].type = cert_po_certList;
786  cvout[cvout_index].value.pointer.chain = NULL;
787  int cvout_cert_list_index = cvout_index;
788  cvout_index++;
789  cvout[cvout_index].type = cert_po_trustAnchor;
790  cvout[cvout_index].value.pointer.cert = NULL;
791  int cvout_trust_anchor_index = cvout_index;
792  cvout_index++;
793  cvout[cvout_index].type = cert_po_end;
794  ScopedCERTValOutParam scoped_cvout(cvout);
795
796  EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
797  SECOidTag ev_policy_oid = SEC_OID_UNKNOWN;
798  bool is_ev_candidate =
799      (flags & CertVerifier::VERIFY_EV_CERT) &&
800      IsEVCandidate(metadata, cert_handle, &ev_policy_oid);
801  bool cert_io_enabled = flags & CertVerifier::VERIFY_CERT_IO_ENABLED;
802  bool check_revocation =
803      cert_io_enabled &&
804      ((flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED) ||
805       ((flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY) &&
806        is_ev_candidate));
807  if (check_revocation)
808    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
809
810  ScopedCERTCertList trust_anchors;
811  if (SupportsAdditionalTrustAnchors() && !additional_trust_anchors.empty()) {
812    trust_anchors.reset(
813        CertificateListToCERTCertList(additional_trust_anchors));
814  }
815
816  status = PKIXVerifyCert(cert_handle, check_revocation, cert_io_enabled,
817                          NULL, 0, trust_anchors.get(), cvout);
818
819  if (status == SECSuccess) {
820    AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
821                          cvout[cvout_trust_anchor_index].value.pointer.cert,
822                          &verify_result->public_key_hashes);
823
824    verify_result->is_issued_by_known_root =
825        IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
826    verify_result->is_issued_by_additional_trust_anchor =
827        IsAdditionalTrustAnchor(
828            trust_anchors.get(),
829            cvout[cvout_trust_anchor_index].value.pointer.cert);
830
831    GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
832                     cvout[cvout_trust_anchor_index].value.pointer.cert,
833                     verify_result);
834  }
835
836  if (crl_set) {
837    CRLSetResult crl_set_result = CheckRevocationWithCRLSet(
838        cvout[cvout_cert_list_index].value.pointer.chain,
839        cvout[cvout_trust_anchor_index].value.pointer.cert,
840        crl_set);
841    if (crl_set_result == kCRLSetRevoked) {
842      PORT_SetError(SEC_ERROR_REVOKED_CERTIFICATE);
843      status = SECFailure;
844    }
845  }
846
847  if (status != SECSuccess) {
848    int err = PORT_GetError();
849    LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
850               << " failed err=" << err;
851    // CERT_PKIXVerifyCert rerports the wrong error code for
852    // expired certificates (NSS bug 491174)
853    if (err == SEC_ERROR_CERT_NOT_VALID &&
854        (verify_result->cert_status & CERT_STATUS_DATE_INVALID))
855      err = SEC_ERROR_EXPIRED_CERTIFICATE;
856    CertStatus cert_status = MapCertErrorToCertStatus(err);
857    if (cert_status) {
858      verify_result->cert_status |= cert_status;
859      return MapCertStatusToNetError(verify_result->cert_status);
860    }
861    // |err| is not a certificate error.
862    return MapSecurityError(err);
863  }
864
865  if (IsCertStatusError(verify_result->cert_status))
866    return MapCertStatusToNetError(verify_result->cert_status);
867
868  if ((flags & CertVerifier::VERIFY_EV_CERT) && is_ev_candidate &&
869      VerifyEV(cert_handle, flags, crl_set, metadata, ev_policy_oid,
870               trust_anchors.get())) {
871    verify_result->cert_status |= CERT_STATUS_IS_EV;
872  }
873
874  return OK;
875}
876
877}  // namespace net
878