cert_verify_proc_nss.cc revision 116680a4aac90f2aa7413d9095a592090648e557 
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
36namespace net {
37
38namespace {
39
40typedef scoped_ptr<
41    CERTCertificatePolicies,
42    crypto::NSSDestroyer<CERTCertificatePolicies,
43                         CERT_DestroyCertificatePoliciesExtension> >
44    ScopedCERTCertificatePolicies;
45
46typedef scoped_ptr<
47    CERTCertList,
48    crypto::NSSDestroyer<CERTCertList, CERT_DestroyCertList> >
49    ScopedCERTCertList;
50
51// ScopedCERTValOutParam manages destruction of values in the CERTValOutParam
52// array that cvout points to.  cvout must be initialized as passed to
53// CERT_PKIXVerifyCert, so that the array must be terminated with
54// cert_po_end type.
55// When it goes out of scope, it destroys values of cert_po_trustAnchor
56// and cert_po_certList types, but doesn't release the array itself.
57class ScopedCERTValOutParam {
58 public:
59  explicit ScopedCERTValOutParam(CERTValOutParam* cvout) : cvout_(cvout) {}
60
61  ~ScopedCERTValOutParam() {
62    Clear();
63  }
64
65  // Free the internal resources, but do not release the array itself.
66  void Clear() {
67    if (cvout_ == NULL)
68      return;
69    for (CERTValOutParam *p = cvout_; p->type != cert_po_end; p++) {
70      switch (p->type) {
71        case cert_po_trustAnchor:
72          if (p->value.pointer.cert) {
73            CERT_DestroyCertificate(p->value.pointer.cert);
74            p->value.pointer.cert = NULL;
75          }
76          break;
77        case cert_po_certList:
78          if (p->value.pointer.chain) {
79            CERT_DestroyCertList(p->value.pointer.chain);
80            p->value.pointer.chain = NULL;
81          }
82          break;
83        default:
84          break;
85      }
86    }
87  }
88
89 private:
90  CERTValOutParam* cvout_;
91
92  DISALLOW_COPY_AND_ASSIGN(ScopedCERTValOutParam);
93};
94
95// Map PORT_GetError() return values to our network error codes.
96int MapSecurityError(int err) {
97  switch (err) {
98    case PR_DIRECTORY_LOOKUP_ERROR:  // DNS lookup error.
99      return ERR_NAME_NOT_RESOLVED;
100    case SEC_ERROR_INVALID_ARGS:
101      return ERR_INVALID_ARGUMENT;
102    case SSL_ERROR_BAD_CERT_DOMAIN:
103      return ERR_CERT_COMMON_NAME_INVALID;
104    case SEC_ERROR_INVALID_TIME:
105    case SEC_ERROR_EXPIRED_CERTIFICATE:
106    case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
107      return ERR_CERT_DATE_INVALID;
108    case SEC_ERROR_UNKNOWN_ISSUER:
109    case SEC_ERROR_UNTRUSTED_ISSUER:
110    case SEC_ERROR_CA_CERT_INVALID:
111    case SEC_ERROR_APPLICATION_CALLBACK_ERROR:  // Rejected by
112                                                // chain_verify_callback.
113      return ERR_CERT_AUTHORITY_INVALID;
114    // TODO(port): map ERR_CERT_NO_REVOCATION_MECHANISM.
115    case SEC_ERROR_OCSP_BAD_HTTP_RESPONSE:
116    case SEC_ERROR_OCSP_SERVER_ERROR:
117      return ERR_CERT_UNABLE_TO_CHECK_REVOCATION;
118    case SEC_ERROR_REVOKED_CERTIFICATE:
119    case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
120      return ERR_CERT_REVOKED;
121    case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
122      return ERR_CERT_NAME_CONSTRAINT_VIOLATION;
123    case SEC_ERROR_BAD_DER:
124    case SEC_ERROR_BAD_SIGNATURE:
125    case SEC_ERROR_CERT_NOT_VALID:
126    // TODO(port): add an ERR_CERT_WRONG_USAGE error code.
127    case SEC_ERROR_CERT_USAGES_INVALID:
128    case SEC_ERROR_INADEQUATE_KEY_USAGE:  // Key usage.
129    case SEC_ERROR_INADEQUATE_CERT_TYPE:  // Extended key usage and whether
130                                          // the certificate is a CA.
131    case SEC_ERROR_POLICY_VALIDATION_FAILED:
132    case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
133    case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
134    case SEC_ERROR_EXTENSION_VALUE_INVALID:
135      return ERR_CERT_INVALID;
136    case SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED:
137      return ERR_CERT_WEAK_SIGNATURE_ALGORITHM;
138    default:
139      LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
140      return ERR_FAILED;
141  }
142}
143
144// Map PORT_GetError() return values to our cert status flags.
145CertStatus MapCertErrorToCertStatus(int err) {
146  int net_error = MapSecurityError(err);
147  return MapNetErrorToCertStatus(net_error);
148}
149
150// Saves some information about the certificate chain cert_list in
151// *verify_result.  The caller MUST initialize *verify_result before calling
152// this function.
153// Note that cert_list[0] is the end entity certificate.
154void GetCertChainInfo(CERTCertList* cert_list,
155                      CERTCertificate* root_cert,
156                      CertVerifyResult* verify_result) {
157  DCHECK(cert_list);
158
159  CERTCertificate* verified_cert = NULL;
160  std::vector<CERTCertificate*> verified_chain;
161  int i = 0;
162  for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
163       !CERT_LIST_END(node, cert_list);
164       node = CERT_LIST_NEXT(node), ++i) {
165    if (i == 0) {
166      verified_cert = node->cert;
167    } else {
168      // Because of an NSS bug, CERT_PKIXVerifyCert may chain a self-signed
169      // certificate of a root CA to another certificate of the same root CA
170      // key.  Detect that error and ignore the root CA certificate.
171      // See https://bugzilla.mozilla.org/show_bug.cgi?id=721288.
172      if (node->cert->isRoot) {
173        // NOTE: isRoot doesn't mean the certificate is a trust anchor.  It
174        // means the certificate is self-signed.  Here we assume isRoot only
175        // implies the certificate is self-issued.
176        CERTCertListNode* next_node = CERT_LIST_NEXT(node);
177        CERTCertificate* next_cert;
178        if (!CERT_LIST_END(next_node, cert_list)) {
179          next_cert = next_node->cert;
180        } else {
181          next_cert = root_cert;
182        }
183        // Test that |node->cert| is actually a self-signed certificate
184        // whose key is equal to |next_cert|, and not a self-issued
185        // certificate signed by another key of the same CA.
186        if (next_cert && SECITEM_ItemsAreEqual(&node->cert->derPublicKey,
187                                               &next_cert->derPublicKey)) {
188          continue;
189        }
190      }
191      verified_chain.push_back(node->cert);
192    }
193
194    SECAlgorithmID& signature = node->cert->signature;
195    SECOidTag oid_tag = SECOID_FindOIDTag(&signature.algorithm);
196    switch (oid_tag) {
197      case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
198        verify_result->has_md5 = true;
199        break;
200      case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
201        verify_result->has_md2 = true;
202        break;
203      case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
204        verify_result->has_md4 = true;
205        break;
206      default:
207        break;
208    }
209  }
210
211  if (root_cert)
212    verified_chain.push_back(root_cert);
213#if defined(OS_IOS)
214  verify_result->verified_cert =
215      x509_util_ios::CreateCertFromNSSHandles(verified_cert, verified_chain);
216#else
217  verify_result->verified_cert =
218      X509Certificate::CreateFromHandle(verified_cert, verified_chain);
219#endif  // defined(OS_IOS)
220}
221
222// IsKnownRoot returns true if the given certificate is one that we believe
223// is a standard (as opposed to user-installed) root.
224bool IsKnownRoot(CERTCertificate* root) {
225  if (!root || !root->slot)
226    return false;
227
228  // This magic name is taken from
229  // http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/security/nss/lib/ckfw/builtins/constants.c&rev=1.13&mark=86,89#79
230  return 0 == strcmp(PK11_GetSlotName(root->slot),
231                     "NSS Builtin Objects");
232}
233
234// Returns true if the given certificate is one of the additional trust anchors.
235bool IsAdditionalTrustAnchor(CERTCertList* additional_trust_anchors,
236                             CERTCertificate* root) {
237  if (!additional_trust_anchors || !root)
238    return false;
239  for (CERTCertListNode* node = CERT_LIST_HEAD(additional_trust_anchors);
240       !CERT_LIST_END(node, additional_trust_anchors);
241       node = CERT_LIST_NEXT(node)) {
242    if (CERT_CompareCerts(node->cert, root))
243      return true;
244  }
245  return false;
246}
247
248enum CRLSetResult {
249  kCRLSetOk,
250  kCRLSetRevoked,
251  kCRLSetUnknown,
252};
253
254// CheckRevocationWithCRLSet attempts to check each element of |cert_list|
255// against |crl_set|. It returns:
256//   kCRLSetRevoked: if any element of the chain is known to have been revoked.
257//   kCRLSetUnknown: if there is no fresh information about the leaf
258//       certificate in the chain or if the CRLSet has expired.
259//
260//       Only the leaf certificate is considered for coverage because some
261//       intermediates have CRLs with no revocations (after filtering) and
262//       those CRLs are pruned from the CRLSet at generation time. This means
263//       that some EV sites would otherwise take the hit of an OCSP lookup for
264//       no reason.
265//   kCRLSetOk: otherwise.
266CRLSetResult CheckRevocationWithCRLSet(CERTCertList* cert_list,
267                                       CERTCertificate* root,
268                                       CRLSet* crl_set) {
269  std::vector<CERTCertificate*> certs;
270
271  if (cert_list) {
272    for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
273         !CERT_LIST_END(node, cert_list);
274         node = CERT_LIST_NEXT(node)) {
275      certs.push_back(node->cert);
276    }
277  }
278  if (root)
279    certs.push_back(root);
280
281  // error is set to true if any errors are found. It causes such chains to be
282  // considered as not covered.
283  bool error = false;
284  // last_covered is set to the coverage state of the previous certificate. The
285  // certificates are iterated over backwards thus, after the iteration,
286  // |last_covered| contains the coverage state of the leaf certificate.
287  bool last_covered = false;
288
289  // We iterate from the root certificate down to the leaf, keeping track of
290  // the issuer's SPKI at each step.
291  std::string issuer_spki_hash;
292  for (std::vector<CERTCertificate*>::reverse_iterator i = certs.rbegin();
293       i != certs.rend(); ++i) {
294    CERTCertificate* cert = *i;
295
296    base::StringPiece der(reinterpret_cast<char*>(cert->derCert.data),
297                          cert->derCert.len);
298
299    base::StringPiece spki;
300    if (!asn1::ExtractSPKIFromDERCert(der, &spki)) {
301      NOTREACHED();
302      error = true;
303      continue;
304    }
305    const std::string spki_hash = crypto::SHA256HashString(spki);
306
307    base::StringPiece serial_number = base::StringPiece(
308        reinterpret_cast<char*>(cert->serialNumber.data),
309        cert->serialNumber.len);
310
311    CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
312
313    if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
314      result = crl_set->CheckSerial(serial_number, issuer_spki_hash);
315
316    issuer_spki_hash = spki_hash;
317
318    switch (result) {
319      case CRLSet::REVOKED:
320        return kCRLSetRevoked;
321      case CRLSet::UNKNOWN:
322        last_covered = false;
323        continue;
324      case CRLSet::GOOD:
325        last_covered = true;
326        continue;
327      default:
328        NOTREACHED();
329        error = true;
330        continue;
331    }
332  }
333
334  if (error || !last_covered || crl_set->IsExpired())
335    return kCRLSetUnknown;
336  return kCRLSetOk;
337}
338
339// Forward declarations.
340SECStatus RetryPKIXVerifyCertWithWorkarounds(
341    CERTCertificate* cert_handle, int num_policy_oids,
342    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
343    CERTValOutParam* cvout);
344SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle);
345
346// Call CERT_PKIXVerifyCert for the cert_handle.
347// Verification results are stored in an array of CERTValOutParam.
348// If |hard_fail| is true, and no policy_oids are supplied (eg: EV is NOT being
349// checked), then the failure to obtain valid CRL/OCSP information for all
350// certificates that contain CRL/OCSP URLs will cause the certificate to be
351// treated as if it was revoked. Since failures may be caused by transient
352// network failures or by malicious attackers, in general, hard_fail should be
353// false.
354// If policy_oids is not NULL and num_policy_oids is positive, policies
355// are also checked.
356// additional_trust_anchors is an optional list of certificates that can be
357// trusted as anchors when building a certificate chain.
358// Caller must initialize cvout before calling this function.
359SECStatus PKIXVerifyCert(CERTCertificate* cert_handle,
360                         bool check_revocation,
361                         bool hard_fail,
362                         bool cert_io_enabled,
363                         const SECOidTag* policy_oids,
364                         int num_policy_oids,
365                         CERTCertList* additional_trust_anchors,
366                         CERTChainVerifyCallback* chain_verify_callback,
367                         CERTValOutParam* cvout) {
368  bool use_crl = check_revocation;
369  bool use_ocsp = check_revocation;
370
371  PRUint64 revocation_method_flags =
372      CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
373      CERT_REV_M_ALLOW_NETWORK_FETCHING |
374      CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
375      CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
376      CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
377  PRUint64 revocation_method_independent_flags =
378      CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
379  if (check_revocation && policy_oids && num_policy_oids > 0) {
380    // EV verification requires revocation checking.  Consider the certificate
381    // revoked if we don't have revocation info.
382    // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
383    // verification or we want strict revocation flags.
384    revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
385    revocation_method_independent_flags |=
386        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
387  } else if (check_revocation && hard_fail) {
388    revocation_method_flags |= CERT_REV_M_FAIL_ON_MISSING_FRESH_INFO;
389    revocation_method_independent_flags |=
390        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
391  } else {
392    revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
393    revocation_method_independent_flags |=
394        CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
395  }
396  PRUint64 method_flags[2];
397  method_flags[cert_revocation_method_crl] = revocation_method_flags;
398  method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
399
400  if (use_crl) {
401    method_flags[cert_revocation_method_crl] |=
402        CERT_REV_M_TEST_USING_THIS_METHOD;
403  }
404  if (use_ocsp) {
405    method_flags[cert_revocation_method_ocsp] |=
406        CERT_REV_M_TEST_USING_THIS_METHOD;
407  }
408
409  CERTRevocationMethodIndex preferred_revocation_methods[1];
410  if (use_ocsp) {
411    preferred_revocation_methods[0] = cert_revocation_method_ocsp;
412  } else {
413    preferred_revocation_methods[0] = cert_revocation_method_crl;
414  }
415
416  CERTRevocationFlags revocation_flags;
417  revocation_flags.leafTests.number_of_defined_methods =
418      arraysize(method_flags);
419  revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
420  revocation_flags.leafTests.number_of_preferred_methods =
421      arraysize(preferred_revocation_methods);
422  revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
423  revocation_flags.leafTests.cert_rev_method_independent_flags =
424      revocation_method_independent_flags;
425
426  revocation_flags.chainTests.number_of_defined_methods =
427      arraysize(method_flags);
428  revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
429  revocation_flags.chainTests.number_of_preferred_methods =
430      arraysize(preferred_revocation_methods);
431  revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
432  revocation_flags.chainTests.cert_rev_method_independent_flags =
433      revocation_method_independent_flags;
434
435
436  std::vector<CERTValInParam> cvin;
437  cvin.reserve(7);
438  CERTValInParam in_param;
439  in_param.type = cert_pi_revocationFlags;
440  in_param.value.pointer.revocation = &revocation_flags;
441  cvin.push_back(in_param);
442  if (policy_oids && num_policy_oids > 0) {
443    in_param.type = cert_pi_policyOID;
444    in_param.value.arraySize = num_policy_oids;
445    in_param.value.array.oids = policy_oids;
446    cvin.push_back(in_param);
447  }
448  if (additional_trust_anchors) {
449    in_param.type = cert_pi_trustAnchors;
450    in_param.value.pointer.chain = additional_trust_anchors;
451    cvin.push_back(in_param);
452    in_param.type = cert_pi_useOnlyTrustAnchors;
453    in_param.value.scalar.b = PR_FALSE;
454    cvin.push_back(in_param);
455  }
456  if (chain_verify_callback) {
457    in_param.type = cert_pi_chainVerifyCallback;
458    in_param.value.pointer.chainVerifyCallback = chain_verify_callback;
459    cvin.push_back(in_param);
460  }
461  in_param.type = cert_pi_end;
462  cvin.push_back(in_param);
463
464  SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
465                                     &cvin[0], cvout, NULL);
466  if (rv != SECSuccess) {
467    rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
468                                            cert_io_enabled, &cvin, cvout);
469  }
470  return rv;
471}
472
473// PKIXVerifyCert calls this function to work around some bugs in
474// CERT_PKIXVerifyCert.  All the arguments of this function are either the
475// arguments or local variables of PKIXVerifyCert.
476SECStatus RetryPKIXVerifyCertWithWorkarounds(
477    CERTCertificate* cert_handle, int num_policy_oids,
478    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
479    CERTValOutParam* cvout) {
480  // We call this function when the first CERT_PKIXVerifyCert call in
481  // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
482  SECStatus rv = SECFailure;
483  int nss_error = PORT_GetError();
484  CERTValInParam in_param;
485
486  // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
487  // CA certificate, so we retry with cert_pi_useAIACertFetch.
488  // cert_pi_useAIACertFetch has several bugs in its error handling and
489  // error reporting (NSS bug 528743), so we don't use it by default.
490  // Note: When building a certificate chain, CERT_PKIXVerifyCert may
491  // incorrectly pick a CA certificate with the same subject name as the
492  // missing intermediate CA certificate, and  fail with the
493  // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
494  // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
495  if (cert_io_enabled &&
496      (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
497       nss_error == SEC_ERROR_BAD_SIGNATURE)) {
498    DCHECK_EQ(cvin->back().type,  cert_pi_end);
499    cvin->pop_back();
500    in_param.type = cert_pi_useAIACertFetch;
501    in_param.value.scalar.b = PR_TRUE;
502    cvin->push_back(in_param);
503    in_param.type = cert_pi_end;
504    cvin->push_back(in_param);
505    rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
506                             &(*cvin)[0], cvout, NULL);
507    if (rv == SECSuccess)
508      return rv;
509    int new_nss_error = PORT_GetError();
510    if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
511        new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
512        new_nss_error == SEC_ERROR_BAD_INFO_ACCESS_LOCATION ||
513        new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
514        new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
515        !IS_SEC_ERROR(new_nss_error)) {
516      // Use the original error code because of cert_pi_useAIACertFetch's
517      // bad error reporting.
518      PORT_SetError(nss_error);
519      return rv;
520    }
521    nss_error = new_nss_error;
522  }
523
524  // If an intermediate CA certificate has requireExplicitPolicy in its
525  // policyConstraints extension, CERT_PKIXVerifyCert fails with
526  // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
527  // certificate policy (NSS bug 552775).  So we retry with the certificate
528  // policy found in the server certificate.
529  if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
530      num_policy_oids == 0) {
531    SECOidTag policy = GetFirstCertPolicy(cert_handle);
532    if (policy != SEC_OID_UNKNOWN) {
533      DCHECK_EQ(cvin->back().type,  cert_pi_end);
534      cvin->pop_back();
535      in_param.type = cert_pi_policyOID;
536      in_param.value.arraySize = 1;
537      in_param.value.array.oids = &policy;
538      cvin->push_back(in_param);
539      in_param.type = cert_pi_end;
540      cvin->push_back(in_param);
541      rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
542                               &(*cvin)[0], cvout, NULL);
543      if (rv != SECSuccess) {
544        // Use the original error code.
545        PORT_SetError(nss_error);
546      }
547    }
548  }
549
550  return rv;
551}
552
553// Decodes the certificatePolicies extension of the certificate.  Returns
554// NULL if the certificate doesn't have the extension or the extension can't
555// be decoded.  The returned value must be freed with a
556// CERT_DestroyCertificatePoliciesExtension call.
557CERTCertificatePolicies* DecodeCertPolicies(
558    CERTCertificate* cert_handle) {
559  SECItem policy_ext;
560  SECStatus rv = CERT_FindCertExtension(cert_handle,
561                                        SEC_OID_X509_CERTIFICATE_POLICIES,
562                                        &policy_ext);
563  if (rv != SECSuccess)
564    return NULL;
565  CERTCertificatePolicies* policies =
566      CERT_DecodeCertificatePoliciesExtension(&policy_ext);
567  SECITEM_FreeItem(&policy_ext, PR_FALSE);
568  return policies;
569}
570
571// Returns the OID tag for the first certificate policy in the certificate's
572// certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
573// has no certificate policy.
574SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle) {
575  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
576  if (!policies.get())
577    return SEC_OID_UNKNOWN;
578
579  CERTPolicyInfo* policy_info = policies->policyInfos[0];
580  if (!policy_info)
581    return SEC_OID_UNKNOWN;
582  if (policy_info->oid != SEC_OID_UNKNOWN)
583    return policy_info->oid;
584
585  // The certificate policy is unknown to NSS.  We need to create a dynamic
586  // OID tag for the policy.
587  SECOidData od;
588  od.oid.len = policy_info->policyID.len;
589  od.oid.data = policy_info->policyID.data;
590  od.offset = SEC_OID_UNKNOWN;
591  // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
592  // default description here.  The description doesn't need to be unique for
593  // each OID.
594  od.desc = "a certificate policy";
595  od.mechanism = CKM_INVALID_MECHANISM;
596  od.supportedExtension = INVALID_CERT_EXTENSION;
597  return SECOID_AddEntry(&od);
598}
599
600HashValue CertPublicKeyHashSHA1(CERTCertificate* cert) {
601  HashValue hash(HASH_VALUE_SHA1);
602#if defined(OS_IOS)
603  CC_SHA1(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
604#else
605  SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data(),
606                              cert->derPublicKey.data, cert->derPublicKey.len);
607  DCHECK_EQ(SECSuccess, rv);
608#endif
609  return hash;
610}
611
612HashValue CertPublicKeyHashSHA256(CERTCertificate* cert) {
613  HashValue hash(HASH_VALUE_SHA256);
614#if defined(OS_IOS)
615  CC_SHA256(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
616#else
617  SECStatus rv = HASH_HashBuf(HASH_AlgSHA256, hash.data(),
618                              cert->derPublicKey.data, cert->derPublicKey.len);
619  DCHECK_EQ(rv, SECSuccess);
620#endif
621  return hash;
622}
623
624void AppendPublicKeyHashes(CERTCertList* cert_list,
625                           CERTCertificate* root_cert,
626                           HashValueVector* hashes) {
627  for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
628       !CERT_LIST_END(node, cert_list);
629       node = CERT_LIST_NEXT(node)) {
630    hashes->push_back(CertPublicKeyHashSHA1(node->cert));
631    hashes->push_back(CertPublicKeyHashSHA256(node->cert));
632  }
633  if (root_cert) {
634    hashes->push_back(CertPublicKeyHashSHA1(root_cert));
635    hashes->push_back(CertPublicKeyHashSHA256(root_cert));
636  }
637}
638
639// Returns true if |cert_handle| contains a policy OID that is an EV policy
640// OID according to |metadata|, storing the resulting policy OID in
641// |*ev_policy_oid|. A true return is not sufficient to establish that a
642// certificate is EV, but a false return is sufficient to establish the
643// certificate cannot be EV.
644bool IsEVCandidate(EVRootCAMetadata* metadata,
645                   CERTCertificate* cert_handle,
646                   SECOidTag* ev_policy_oid) {
647  DCHECK(cert_handle);
648  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
649  if (!policies.get())
650    return false;
651
652  CERTPolicyInfo** policy_infos = policies->policyInfos;
653  while (*policy_infos != NULL) {
654    CERTPolicyInfo* policy_info = *policy_infos++;
655    // If the Policy OID is unknown, that implicitly means it has not been
656    // registered as an EV policy.
657    if (policy_info->oid == SEC_OID_UNKNOWN)
658      continue;
659    if (metadata->IsEVPolicyOID(policy_info->oid)) {
660      *ev_policy_oid = policy_info->oid;
661      return true;
662    }
663  }
664
665  return false;
666}
667
668// Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
669// and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
670// TODO(wtc): A possible optimization is that we get the trust anchor from
671// the first PKIXVerifyCert call.  We look up the EV policy for the trust
672// anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
673// Otherwise, we pass just that EV policy (as opposed to all the EV policies)
674// to the second PKIXVerifyCert call.
675bool VerifyEV(CERTCertificate* cert_handle,
676              int flags,
677              CRLSet* crl_set,
678              bool rev_checking_enabled,
679              EVRootCAMetadata* metadata,
680              SECOidTag ev_policy_oid,
681              CERTCertList* additional_trust_anchors,
682              CERTChainVerifyCallback* chain_verify_callback) {
683  CERTValOutParam cvout[3];
684  int cvout_index = 0;
685  cvout[cvout_index].type = cert_po_certList;
686  cvout[cvout_index].value.pointer.chain = NULL;
687  int cvout_cert_list_index = cvout_index;
688  cvout_index++;
689  cvout[cvout_index].type = cert_po_trustAnchor;
690  cvout[cvout_index].value.pointer.cert = NULL;
691  int cvout_trust_anchor_index = cvout_index;
692  cvout_index++;
693  cvout[cvout_index].type = cert_po_end;
694  ScopedCERTValOutParam scoped_cvout(cvout);
695
696  SECStatus status = PKIXVerifyCert(
697      cert_handle,
698      rev_checking_enabled,
699      true, /* hard fail is implied in EV. */
700      flags & CertVerifier::VERIFY_CERT_IO_ENABLED,
701      &ev_policy_oid,
702      1,
703      additional_trust_anchors,
704      chain_verify_callback,
705      cvout);
706  if (status != SECSuccess)
707    return false;
708
709  CERTCertificate* root_ca =
710      cvout[cvout_trust_anchor_index].value.pointer.cert;
711  if (root_ca == NULL)
712    return false;
713
714  // This second PKIXVerifyCert call could have found a different certification
715  // path and one or more of the certificates on this new path, that weren't on
716  // the old path, might have been revoked.
717  if (crl_set) {
718    CRLSetResult crl_set_result = CheckRevocationWithCRLSet(
719        cvout[cvout_cert_list_index].value.pointer.chain,
720        cvout[cvout_trust_anchor_index].value.pointer.cert,
721        crl_set);
722    if (crl_set_result == kCRLSetRevoked)
723      return false;
724  }
725
726#if defined(OS_IOS)
727  SHA1HashValue fingerprint = x509_util_ios::CalculateFingerprintNSS(root_ca);
728#else
729  SHA1HashValue fingerprint =
730      X509Certificate::CalculateFingerprint(root_ca);
731#endif
732  return metadata->HasEVPolicyOID(fingerprint, ev_policy_oid);
733}
734
735CERTCertList* CertificateListToCERTCertList(const CertificateList& list) {
736  CERTCertList* result = CERT_NewCertList();
737  for (size_t i = 0; i < list.size(); ++i) {
738#if defined(OS_IOS)
739    // X509Certificate::os_cert_handle() on iOS is a SecCertificateRef; convert
740    // it to an NSS CERTCertificate.
741    CERTCertificate* cert = x509_util_ios::CreateNSSCertHandleFromOSHandle(
742        list[i]->os_cert_handle());
743#else
744    CERTCertificate* cert = list[i]->os_cert_handle();
745#endif
746    CERT_AddCertToListTail(result, CERT_DupCertificate(cert));
747  }
748  return result;
749}
750
751}  // namespace
752
753CertVerifyProcNSS::CertVerifyProcNSS() {}
754
755CertVerifyProcNSS::~CertVerifyProcNSS() {}
756
757bool CertVerifyProcNSS::SupportsAdditionalTrustAnchors() const {
758  return true;
759}
760
761int CertVerifyProcNSS::VerifyInternalImpl(
762    X509Certificate* cert,
763    const std::string& hostname,
764    int flags,
765    CRLSet* crl_set,
766    const CertificateList& additional_trust_anchors,
767    CERTChainVerifyCallback* chain_verify_callback,
768    CertVerifyResult* verify_result) {
769#if defined(OS_IOS)
770  // For iOS, the entire chain must be loaded into NSS's in-memory certificate
771  // store.
772  x509_util_ios::NSSCertChain scoped_chain(cert);
773  CERTCertificate* cert_handle = scoped_chain.cert_handle();
774#else
775  CERTCertificate* cert_handle = cert->os_cert_handle();
776#endif  // defined(OS_IOS)
777
778  if (!cert->VerifyNameMatch(hostname,
779                             &verify_result->common_name_fallback_used)) {
780    verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
781  }
782
783  // Make sure that the cert is valid now.
784  SECCertTimeValidity validity = CERT_CheckCertValidTimes(
785      cert_handle, PR_Now(), PR_TRUE);
786  if (validity != secCertTimeValid)
787    verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
788
789  CERTValOutParam cvout[3];
790  int cvout_index = 0;
791  cvout[cvout_index].type = cert_po_certList;
792  cvout[cvout_index].value.pointer.chain = NULL;
793  int cvout_cert_list_index = cvout_index;
794  cvout_index++;
795  cvout[cvout_index].type = cert_po_trustAnchor;
796  cvout[cvout_index].value.pointer.cert = NULL;
797  int cvout_trust_anchor_index = cvout_index;
798  cvout_index++;
799  cvout[cvout_index].type = cert_po_end;
800  ScopedCERTValOutParam scoped_cvout(cvout);
801
802  EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
803  SECOidTag ev_policy_oid = SEC_OID_UNKNOWN;
804  bool is_ev_candidate =
805      (flags & CertVerifier::VERIFY_EV_CERT) &&
806      IsEVCandidate(metadata, cert_handle, &ev_policy_oid);
807  bool cert_io_enabled = flags & CertVerifier::VERIFY_CERT_IO_ENABLED;
808  bool check_revocation =
809      cert_io_enabled &&
810      (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED);
811  if (check_revocation)
812    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
813
814  ScopedCERTCertList trust_anchors;
815  if (!additional_trust_anchors.empty()) {
816    trust_anchors.reset(
817        CertificateListToCERTCertList(additional_trust_anchors));
818  }
819
820  SECStatus status = PKIXVerifyCert(cert_handle,
821                                    check_revocation,
822                                    false,
823                                    cert_io_enabled,
824                                    NULL,
825                                    0,
826                                    trust_anchors.get(),
827                                    chain_verify_callback,
828                                    cvout);
829
830  if (status == SECSuccess &&
831      (flags & CertVerifier::VERIFY_REV_CHECKING_REQUIRED_LOCAL_ANCHORS) &&
832      !IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert)) {
833    // TODO(rsleevi): Optimize this by supplying the constructed chain to
834    // libpkix via cvin. Omitting for now, due to lack of coverage in upstream
835    // NSS tests for that feature.
836    scoped_cvout.Clear();
837    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
838    status = PKIXVerifyCert(cert_handle,
839                            true,
840                            true,
841                            cert_io_enabled,
842                            NULL,
843                            0,
844                            trust_anchors.get(),
845                            chain_verify_callback,
846                            cvout);
847  }
848
849  if (status == SECSuccess) {
850    AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
851                          cvout[cvout_trust_anchor_index].value.pointer.cert,
852                          &verify_result->public_key_hashes);
853
854    verify_result->is_issued_by_known_root =
855        IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
856    verify_result->is_issued_by_additional_trust_anchor =
857        IsAdditionalTrustAnchor(
858            trust_anchors.get(),
859            cvout[cvout_trust_anchor_index].value.pointer.cert);
860
861    GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
862                     cvout[cvout_trust_anchor_index].value.pointer.cert,
863                     verify_result);
864  }
865
866  CRLSetResult crl_set_result = kCRLSetUnknown;
867  if (crl_set) {
868    crl_set_result = CheckRevocationWithCRLSet(
869        cvout[cvout_cert_list_index].value.pointer.chain,
870        cvout[cvout_trust_anchor_index].value.pointer.cert,
871        crl_set);
872    if (crl_set_result == kCRLSetRevoked) {
873      PORT_SetError(SEC_ERROR_REVOKED_CERTIFICATE);
874      status = SECFailure;
875    }
876  }
877
878  if (status != SECSuccess) {
879    int err = PORT_GetError();
880    LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
881               << " failed err=" << err;
882    // CERT_PKIXVerifyCert rerports the wrong error code for
883    // expired certificates (NSS bug 491174)
884    if (err == SEC_ERROR_CERT_NOT_VALID &&
885        (verify_result->cert_status & CERT_STATUS_DATE_INVALID))
886      err = SEC_ERROR_EXPIRED_CERTIFICATE;
887    CertStatus cert_status = MapCertErrorToCertStatus(err);
888    if (cert_status) {
889      verify_result->cert_status |= cert_status;
890      return MapCertStatusToNetError(verify_result->cert_status);
891    }
892    // |err| is not a certificate error.
893    return MapSecurityError(err);
894  }
895
896  if (IsCertStatusError(verify_result->cert_status))
897    return MapCertStatusToNetError(verify_result->cert_status);
898
899  if ((flags & CertVerifier::VERIFY_EV_CERT) && is_ev_candidate) {
900    check_revocation |=
901        crl_set_result != kCRLSetOk &&
902        cert_io_enabled &&
903        (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY);
904    if (check_revocation)
905      verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
906
907    if (VerifyEV(cert_handle,
908                 flags,
909                 crl_set,
910                 check_revocation,
911                 metadata,
912                 ev_policy_oid,
913                 trust_anchors.get(),
914                 chain_verify_callback)) {
915      verify_result->cert_status |= CERT_STATUS_IS_EV;
916    }
917  }
918
919  return OK;
920}
921
922int CertVerifyProcNSS::VerifyInternal(
923    X509Certificate* cert,
924    const std::string& hostname,
925    int flags,
926    CRLSet* crl_set,
927    const CertificateList& additional_trust_anchors,
928    CertVerifyResult* verify_result) {
929  return VerifyInternalImpl(cert,
930                            hostname,
931                            flags,
932                            crl_set,
933                            additional_trust_anchors,
934                            NULL,  // chain_verify_callback
935                            verify_result);
936}
937
938}  // namespace net
939