cert_verify_proc_nss.cc revision 3551c9c881056c480085172ff9840cab31610854
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) : cvout_(cvout) {}
71
72  ~ScopedCERTValOutParam() {
73    Clear();
74  }
75
76  // Free the internal resources, but do not release the array itself.
77  void Clear() {
78    if (cvout_ == NULL)
79      return;
80    for (CERTValOutParam *p = cvout_; p->type != cert_po_end; p++) {
81      switch (p->type) {
82        case cert_po_trustAnchor:
83          if (p->value.pointer.cert) {
84            CERT_DestroyCertificate(p->value.pointer.cert);
85            p->value.pointer.cert = NULL;
86          }
87          break;
88        case cert_po_certList:
89          if (p->value.pointer.chain) {
90            CERT_DestroyCertList(p->value.pointer.chain);
91            p->value.pointer.chain = NULL;
92          }
93          break;
94        default:
95          break;
96      }
97    }
98  }
99
100 private:
101  CERTValOutParam* cvout_;
102
103  DISALLOW_COPY_AND_ASSIGN(ScopedCERTValOutParam);
104};
105
106// Map PORT_GetError() return values to our network error codes.
107int MapSecurityError(int err) {
108  switch (err) {
109    case PR_DIRECTORY_LOOKUP_ERROR:  // DNS lookup error.
110      return ERR_NAME_NOT_RESOLVED;
111    case SEC_ERROR_INVALID_ARGS:
112      return ERR_INVALID_ARGUMENT;
113    case SSL_ERROR_BAD_CERT_DOMAIN:
114      return ERR_CERT_COMMON_NAME_INVALID;
115    case SEC_ERROR_INVALID_TIME:
116    case SEC_ERROR_EXPIRED_CERTIFICATE:
117    case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
118      return ERR_CERT_DATE_INVALID;
119    case SEC_ERROR_UNKNOWN_ISSUER:
120    case SEC_ERROR_UNTRUSTED_ISSUER:
121    case SEC_ERROR_CA_CERT_INVALID:
122      return ERR_CERT_AUTHORITY_INVALID;
123    // TODO(port): map ERR_CERT_NO_REVOCATION_MECHANISM.
124    case SEC_ERROR_OCSP_BAD_HTTP_RESPONSE:
125    case SEC_ERROR_OCSP_SERVER_ERROR:
126      return ERR_CERT_UNABLE_TO_CHECK_REVOCATION;
127    case SEC_ERROR_REVOKED_CERTIFICATE:
128    case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
129      return ERR_CERT_REVOKED;
130    case SEC_ERROR_BAD_DER:
131    case SEC_ERROR_BAD_SIGNATURE:
132    case SEC_ERROR_CERT_NOT_VALID:
133    // TODO(port): add an ERR_CERT_WRONG_USAGE error code.
134    case SEC_ERROR_CERT_USAGES_INVALID:
135    case SEC_ERROR_INADEQUATE_KEY_USAGE:  // Key usage.
136    case SEC_ERROR_INADEQUATE_CERT_TYPE:  // Extended key usage and whether
137                                          // the certificate is a CA.
138    case SEC_ERROR_POLICY_VALIDATION_FAILED:
139    case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
140    case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
141    case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
142    case SEC_ERROR_EXTENSION_VALUE_INVALID:
143      return ERR_CERT_INVALID;
144    case SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED:
145      return ERR_CERT_WEAK_SIGNATURE_ALGORITHM;
146    default:
147      LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
148      return ERR_FAILED;
149  }
150}
151
152// Map PORT_GetError() return values to our cert status flags.
153CertStatus MapCertErrorToCertStatus(int err) {
154  int net_error = MapSecurityError(err);
155  return MapNetErrorToCertStatus(net_error);
156}
157
158// Saves some information about the certificate chain cert_list in
159// *verify_result.  The caller MUST initialize *verify_result before calling
160// this function.
161// Note that cert_list[0] is the end entity certificate.
162void GetCertChainInfo(CERTCertList* cert_list,
163                      CERTCertificate* root_cert,
164                      CertVerifyResult* verify_result) {
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  kCRLSetOk,
258  kCRLSetRevoked,
259  kCRLSetUnknown,
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//   kCRLSetUnknown: if there is no fresh information about some element in
266//       the chain.
267//   kCRLSetOk: if every element in the chain is covered by a fresh CRLSet and
268//       is unrevoked.
269CRLSetResult CheckRevocationWithCRLSet(CERTCertList* cert_list,
270                                       CERTCertificate* root,
271                                       CRLSet* crl_set) {
272  std::vector<CERTCertificate*> certs;
273
274  if (cert_list) {
275    for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
276         !CERT_LIST_END(node, cert_list);
277         node = CERT_LIST_NEXT(node)) {
278      certs.push_back(node->cert);
279    }
280  }
281  if (root)
282    certs.push_back(root);
283
284  bool covered = true;
285
286  // We iterate from the root certificate down to the leaf, keeping track of
287  // the issuer's SPKI at each step.
288  std::string issuer_spki_hash;
289  for (std::vector<CERTCertificate*>::reverse_iterator i = certs.rbegin();
290       i != certs.rend(); ++i) {
291    CERTCertificate* cert = *i;
292
293    base::StringPiece der(reinterpret_cast<char*>(cert->derCert.data),
294                          cert->derCert.len);
295
296    base::StringPiece spki;
297    if (!asn1::ExtractSPKIFromDERCert(der, &spki)) {
298      NOTREACHED();
299      covered = false;
300      continue;
301    }
302    const std::string spki_hash = crypto::SHA256HashString(spki);
303
304    base::StringPiece serial_number = base::StringPiece(
305        reinterpret_cast<char*>(cert->serialNumber.data),
306        cert->serialNumber.len);
307
308    CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
309
310    if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
311      result = crl_set->CheckSerial(serial_number, issuer_spki_hash);
312
313    issuer_spki_hash = spki_hash;
314
315    switch (result) {
316      case CRLSet::REVOKED:
317        return kCRLSetRevoked;
318      case CRLSet::UNKNOWN:
319        covered = false;
320        continue;
321      case CRLSet::GOOD:
322        continue;
323      default:
324        NOTREACHED();
325        covered = false;
326        continue;
327    }
328  }
329
330  if (!covered || crl_set->IsExpired())
331    return kCRLSetUnknown;
332  return kCRLSetOk;
333}
334
335// Forward declarations.
336SECStatus RetryPKIXVerifyCertWithWorkarounds(
337    CERTCertificate* cert_handle, int num_policy_oids,
338    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
339    CERTValOutParam* cvout);
340SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle);
341
342// Call CERT_PKIXVerifyCert for the cert_handle.
343// Verification results are stored in an array of CERTValOutParam.
344// If |hard_fail| is true, and no policy_oids are supplied (eg: EV is NOT being
345// checked), then the failure to obtain valid CRL/OCSP information for all
346// certificates that contain CRL/OCSP URLs will cause the certificate to be
347// treated as if it was revoked. Since failures may be caused by transient
348// network failures or by malicious attackers, in general, hard_fail should be
349// false.
350// If policy_oids is not NULL and num_policy_oids is positive, policies
351// are also checked.
352// additional_trust_anchors is an optional list of certificates that can be
353// trusted as anchors when building a certificate chain.
354// Caller must initialize cvout before calling this function.
355SECStatus PKIXVerifyCert(CERTCertificate* cert_handle,
356                         bool check_revocation,
357                         bool hard_fail,
358                         bool cert_io_enabled,
359                         const SECOidTag* policy_oids,
360                         int num_policy_oids,
361                         CERTCertList* additional_trust_anchors,
362                         CERTValOutParam* cvout) {
363  bool use_crl = check_revocation;
364  bool use_ocsp = check_revocation;
365
366  PRUint64 revocation_method_flags =
367      CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
368      CERT_REV_M_ALLOW_NETWORK_FETCHING |
369      CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
370      CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
371      CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
372  PRUint64 revocation_method_independent_flags =
373      CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
374  if (check_revocation && policy_oids && num_policy_oids > 0) {
375    // EV verification requires revocation checking.  Consider the certificate
376    // revoked if we don't have revocation info.
377    // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
378    // verification or we want strict revocation flags.
379    revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
380    revocation_method_independent_flags |=
381        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
382  } else if (check_revocation && hard_fail) {
383    revocation_method_flags |= CERT_REV_M_FAIL_ON_MISSING_FRESH_INFO;
384    revocation_method_independent_flags |=
385        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
386  } else {
387    revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
388    revocation_method_independent_flags |=
389        CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
390  }
391  PRUint64 method_flags[2];
392  method_flags[cert_revocation_method_crl] = revocation_method_flags;
393  method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
394
395  if (use_crl) {
396    method_flags[cert_revocation_method_crl] |=
397        CERT_REV_M_TEST_USING_THIS_METHOD;
398  }
399  if (use_ocsp) {
400    method_flags[cert_revocation_method_ocsp] |=
401        CERT_REV_M_TEST_USING_THIS_METHOD;
402  }
403
404  CERTRevocationMethodIndex preferred_revocation_methods[1];
405  if (use_ocsp) {
406    preferred_revocation_methods[0] = cert_revocation_method_ocsp;
407  } else {
408    preferred_revocation_methods[0] = cert_revocation_method_crl;
409  }
410
411  CERTRevocationFlags revocation_flags;
412  revocation_flags.leafTests.number_of_defined_methods =
413      arraysize(method_flags);
414  revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
415  revocation_flags.leafTests.number_of_preferred_methods =
416      arraysize(preferred_revocation_methods);
417  revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
418  revocation_flags.leafTests.cert_rev_method_independent_flags =
419      revocation_method_independent_flags;
420
421  revocation_flags.chainTests.number_of_defined_methods =
422      arraysize(method_flags);
423  revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
424  revocation_flags.chainTests.number_of_preferred_methods =
425      arraysize(preferred_revocation_methods);
426  revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
427  revocation_flags.chainTests.cert_rev_method_independent_flags =
428      revocation_method_independent_flags;
429
430
431  std::vector<CERTValInParam> cvin;
432  cvin.reserve(7);
433  CERTValInParam in_param;
434  in_param.type = cert_pi_revocationFlags;
435  in_param.value.pointer.revocation = &revocation_flags;
436  cvin.push_back(in_param);
437  if (policy_oids && num_policy_oids > 0) {
438    in_param.type = cert_pi_policyOID;
439    in_param.value.arraySize = num_policy_oids;
440    in_param.value.array.oids = policy_oids;
441    cvin.push_back(in_param);
442  }
443  if (additional_trust_anchors) {
444    in_param.type = cert_pi_trustAnchors;
445    in_param.value.pointer.chain = additional_trust_anchors;
446    cvin.push_back(in_param);
447    in_param.type = cert_pi_useOnlyTrustAnchors;
448    in_param.value.scalar.b = PR_FALSE;
449    cvin.push_back(in_param);
450  }
451  in_param.type = cert_pi_end;
452  cvin.push_back(in_param);
453
454  SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
455                                     &cvin[0], cvout, NULL);
456  if (rv != SECSuccess) {
457    rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
458                                            cert_io_enabled, &cvin, cvout);
459  }
460  return rv;
461}
462
463// PKIXVerifyCert calls this function to work around some bugs in
464// CERT_PKIXVerifyCert.  All the arguments of this function are either the
465// arguments or local variables of PKIXVerifyCert.
466SECStatus RetryPKIXVerifyCertWithWorkarounds(
467    CERTCertificate* cert_handle, int num_policy_oids,
468    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
469    CERTValOutParam* cvout) {
470  // We call this function when the first CERT_PKIXVerifyCert call in
471  // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
472  SECStatus rv = SECFailure;
473  int nss_error = PORT_GetError();
474  CERTValInParam in_param;
475
476  // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
477  // CA certificate, so we retry with cert_pi_useAIACertFetch.
478  // cert_pi_useAIACertFetch has several bugs in its error handling and
479  // error reporting (NSS bug 528743), so we don't use it by default.
480  // Note: When building a certificate chain, CERT_PKIXVerifyCert may
481  // incorrectly pick a CA certificate with the same subject name as the
482  // missing intermediate CA certificate, and  fail with the
483  // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
484  // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
485  if (cert_io_enabled &&
486      (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
487       nss_error == SEC_ERROR_BAD_SIGNATURE)) {
488    DCHECK_EQ(cvin->back().type,  cert_pi_end);
489    cvin->pop_back();
490    in_param.type = cert_pi_useAIACertFetch;
491    in_param.value.scalar.b = PR_TRUE;
492    cvin->push_back(in_param);
493    in_param.type = cert_pi_end;
494    cvin->push_back(in_param);
495    rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
496                             &(*cvin)[0], cvout, NULL);
497    if (rv == SECSuccess)
498      return rv;
499    int new_nss_error = PORT_GetError();
500    if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
501        new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
502        new_nss_error == SEC_ERROR_BAD_INFO_ACCESS_LOCATION ||
503        new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
504        new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
505        !IS_SEC_ERROR(new_nss_error)) {
506      // Use the original error code because of cert_pi_useAIACertFetch's
507      // bad error reporting.
508      PORT_SetError(nss_error);
509      return rv;
510    }
511    nss_error = new_nss_error;
512  }
513
514  // If an intermediate CA certificate has requireExplicitPolicy in its
515  // policyConstraints extension, CERT_PKIXVerifyCert fails with
516  // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
517  // certificate policy (NSS bug 552775).  So we retry with the certificate
518  // policy found in the server certificate.
519  if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
520      num_policy_oids == 0) {
521    SECOidTag policy = GetFirstCertPolicy(cert_handle);
522    if (policy != SEC_OID_UNKNOWN) {
523      DCHECK_EQ(cvin->back().type,  cert_pi_end);
524      cvin->pop_back();
525      in_param.type = cert_pi_policyOID;
526      in_param.value.arraySize = 1;
527      in_param.value.array.oids = &policy;
528      cvin->push_back(in_param);
529      in_param.type = cert_pi_end;
530      cvin->push_back(in_param);
531      rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
532                               &(*cvin)[0], cvout, NULL);
533      if (rv != SECSuccess) {
534        // Use the original error code.
535        PORT_SetError(nss_error);
536      }
537    }
538  }
539
540  return rv;
541}
542
543// Decodes the certificatePolicies extension of the certificate.  Returns
544// NULL if the certificate doesn't have the extension or the extension can't
545// be decoded.  The returned value must be freed with a
546// CERT_DestroyCertificatePoliciesExtension call.
547CERTCertificatePolicies* DecodeCertPolicies(
548    CERTCertificate* cert_handle) {
549  SECItem policy_ext;
550  SECStatus rv = CERT_FindCertExtension(cert_handle,
551                                        SEC_OID_X509_CERTIFICATE_POLICIES,
552                                        &policy_ext);
553  if (rv != SECSuccess)
554    return NULL;
555  CERTCertificatePolicies* policies =
556      CERT_DecodeCertificatePoliciesExtension(&policy_ext);
557  SECITEM_FreeItem(&policy_ext, PR_FALSE);
558  return policies;
559}
560
561// Returns the OID tag for the first certificate policy in the certificate's
562// certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
563// has no certificate policy.
564SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle) {
565  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
566  if (!policies.get())
567    return SEC_OID_UNKNOWN;
568
569  CERTPolicyInfo* policy_info = policies->policyInfos[0];
570  if (!policy_info)
571    return SEC_OID_UNKNOWN;
572  if (policy_info->oid != SEC_OID_UNKNOWN)
573    return policy_info->oid;
574
575  // The certificate policy is unknown to NSS.  We need to create a dynamic
576  // OID tag for the policy.
577  SECOidData od;
578  od.oid.len = policy_info->policyID.len;
579  od.oid.data = policy_info->policyID.data;
580  od.offset = SEC_OID_UNKNOWN;
581  // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
582  // default description here.  The description doesn't need to be unique for
583  // each OID.
584  od.desc = "a certificate policy";
585  od.mechanism = CKM_INVALID_MECHANISM;
586  od.supportedExtension = INVALID_CERT_EXTENSION;
587  return SECOID_AddEntry(&od);
588}
589
590HashValue CertPublicKeyHashSHA1(CERTCertificate* cert) {
591  HashValue hash(HASH_VALUE_SHA1);
592#if defined(OS_IOS)
593  CC_SHA1(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
594#else
595  SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data(),
596                              cert->derPublicKey.data, cert->derPublicKey.len);
597  DCHECK_EQ(SECSuccess, rv);
598#endif
599  return hash;
600}
601
602HashValue CertPublicKeyHashSHA256(CERTCertificate* cert) {
603  HashValue hash(HASH_VALUE_SHA256);
604#if defined(OS_IOS)
605  CC_SHA256(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
606#else
607  SECStatus rv = HASH_HashBuf(HASH_AlgSHA256, hash.data(),
608                              cert->derPublicKey.data, cert->derPublicKey.len);
609  DCHECK_EQ(rv, SECSuccess);
610#endif
611  return hash;
612}
613
614void AppendPublicKeyHashes(CERTCertList* cert_list,
615                           CERTCertificate* root_cert,
616                           HashValueVector* hashes) {
617  for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
618       !CERT_LIST_END(node, cert_list);
619       node = CERT_LIST_NEXT(node)) {
620    hashes->push_back(CertPublicKeyHashSHA1(node->cert));
621    hashes->push_back(CertPublicKeyHashSHA256(node->cert));
622  }
623  if (root_cert) {
624    hashes->push_back(CertPublicKeyHashSHA1(root_cert));
625    hashes->push_back(CertPublicKeyHashSHA256(root_cert));
626  }
627}
628
629// Returns true if |cert_handle| contains a policy OID that is an EV policy
630// OID according to |metadata|, storing the resulting policy OID in
631// |*ev_policy_oid|. A true return is not sufficient to establish that a
632// certificate is EV, but a false return is sufficient to establish the
633// certificate cannot be EV.
634bool IsEVCandidate(EVRootCAMetadata* metadata,
635                   CERTCertificate* cert_handle,
636                   SECOidTag* ev_policy_oid) {
637  DCHECK(cert_handle);
638  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
639  if (!policies.get())
640    return false;
641
642  CERTPolicyInfo** policy_infos = policies->policyInfos;
643  while (*policy_infos != NULL) {
644    CERTPolicyInfo* policy_info = *policy_infos++;
645    // If the Policy OID is unknown, that implicitly means it has not been
646    // registered as an EV policy.
647    if (policy_info->oid == SEC_OID_UNKNOWN)
648      continue;
649    if (metadata->IsEVPolicyOID(policy_info->oid)) {
650      *ev_policy_oid = policy_info->oid;
651      return true;
652    }
653  }
654
655  return false;
656}
657
658// Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
659// and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
660// TODO(wtc): A possible optimization is that we get the trust anchor from
661// the first PKIXVerifyCert call.  We look up the EV policy for the trust
662// anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
663// Otherwise, we pass just that EV policy (as opposed to all the EV policies)
664// to the second PKIXVerifyCert call.
665bool VerifyEV(CERTCertificate* cert_handle,
666              int flags,
667              CRLSet* crl_set,
668              bool rev_checking_enabled,
669              EVRootCAMetadata* metadata,
670              SECOidTag ev_policy_oid,
671              CERTCertList* additional_trust_anchors) {
672  CERTValOutParam cvout[3];
673  int cvout_index = 0;
674  cvout[cvout_index].type = cert_po_certList;
675  cvout[cvout_index].value.pointer.chain = NULL;
676  int cvout_cert_list_index = cvout_index;
677  cvout_index++;
678  cvout[cvout_index].type = cert_po_trustAnchor;
679  cvout[cvout_index].value.pointer.cert = NULL;
680  int cvout_trust_anchor_index = cvout_index;
681  cvout_index++;
682  cvout[cvout_index].type = cert_po_end;
683  ScopedCERTValOutParam scoped_cvout(cvout);
684
685  SECStatus status = PKIXVerifyCert(
686      cert_handle,
687      rev_checking_enabled,
688      true, /* hard fail is implied in EV. */
689      flags & CertVerifier::VERIFY_CERT_IO_ENABLED,
690      &ev_policy_oid,
691      1,
692      additional_trust_anchors,
693      cvout);
694  if (status != SECSuccess)
695    return false;
696
697  CERTCertificate* root_ca =
698      cvout[cvout_trust_anchor_index].value.pointer.cert;
699  if (root_ca == NULL)
700    return false;
701
702  // This second PKIXVerifyCert call could have found a different certification
703  // path and one or more of the certificates on this new path, that weren't on
704  // the old path, might have been revoked.
705  if (crl_set) {
706    CRLSetResult crl_set_result = CheckRevocationWithCRLSet(
707        cvout[cvout_cert_list_index].value.pointer.chain,
708        cvout[cvout_trust_anchor_index].value.pointer.cert,
709        crl_set);
710    if (crl_set_result == kCRLSetRevoked)
711      return false;
712  }
713
714#if defined(OS_IOS)
715  SHA1HashValue fingerprint = x509_util_ios::CalculateFingerprintNSS(root_ca);
716#else
717  SHA1HashValue fingerprint =
718      X509Certificate::CalculateFingerprint(root_ca);
719#endif
720  return metadata->HasEVPolicyOID(fingerprint, ev_policy_oid);
721}
722
723CERTCertList* CertificateListToCERTCertList(const CertificateList& list) {
724  CERTCertList* result = CERT_NewCertList();
725  for (size_t i = 0; i < list.size(); ++i) {
726#if defined(OS_IOS)
727    // X509Certificate::os_cert_handle() on iOS is a SecCertificateRef; convert
728    // it to an NSS CERTCertificate.
729    CERTCertificate* cert = x509_util_ios::CreateNSSCertHandleFromOSHandle(
730        list[i]->os_cert_handle());
731#else
732    CERTCertificate* cert = list[i]->os_cert_handle();
733#endif
734    CERT_AddCertToListTail(result, CERT_DupCertificate(cert));
735  }
736  return result;
737}
738
739}  // namespace
740
741CertVerifyProcNSS::CertVerifyProcNSS() {}
742
743CertVerifyProcNSS::~CertVerifyProcNSS() {}
744
745bool CertVerifyProcNSS::SupportsAdditionalTrustAnchors() const {
746  // This requires APIs introduced in 3.14.2.
747  return NSS_VersionCheck("3.14.2");
748}
749
750int CertVerifyProcNSS::VerifyInternal(
751    X509Certificate* cert,
752    const std::string& hostname,
753    int flags,
754    CRLSet* crl_set,
755    const CertificateList& additional_trust_anchors,
756    CertVerifyResult* verify_result) {
757#if defined(OS_IOS)
758  // For iOS, the entire chain must be loaded into NSS's in-memory certificate
759  // store.
760  x509_util_ios::NSSCertChain scoped_chain(cert);
761  CERTCertificate* cert_handle = scoped_chain.cert_handle();
762#else
763  CERTCertificate* cert_handle = cert->os_cert_handle();
764#endif  // defined(OS_IOS)
765
766  // Make sure that the hostname matches with the common name of the cert.
767  if (!cert->VerifyNameMatch(hostname))
768    verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
769
770  // Make sure that the cert is valid now.
771  SECCertTimeValidity validity = CERT_CheckCertValidTimes(
772      cert_handle, PR_Now(), PR_TRUE);
773  if (validity != secCertTimeValid)
774    verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
775
776  CERTValOutParam cvout[3];
777  int cvout_index = 0;
778  cvout[cvout_index].type = cert_po_certList;
779  cvout[cvout_index].value.pointer.chain = NULL;
780  int cvout_cert_list_index = cvout_index;
781  cvout_index++;
782  cvout[cvout_index].type = cert_po_trustAnchor;
783  cvout[cvout_index].value.pointer.cert = NULL;
784  int cvout_trust_anchor_index = cvout_index;
785  cvout_index++;
786  cvout[cvout_index].type = cert_po_end;
787  ScopedCERTValOutParam scoped_cvout(cvout);
788
789  EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
790  SECOidTag ev_policy_oid = SEC_OID_UNKNOWN;
791  bool is_ev_candidate =
792      (flags & CertVerifier::VERIFY_EV_CERT) &&
793      IsEVCandidate(metadata, cert_handle, &ev_policy_oid);
794  bool cert_io_enabled = flags & CertVerifier::VERIFY_CERT_IO_ENABLED;
795  bool check_revocation =
796      cert_io_enabled &&
797      (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED);
798  if (check_revocation)
799    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
800
801  ScopedCERTCertList trust_anchors;
802  if (SupportsAdditionalTrustAnchors() && !additional_trust_anchors.empty()) {
803    trust_anchors.reset(
804        CertificateListToCERTCertList(additional_trust_anchors));
805  }
806
807  SECStatus status = PKIXVerifyCert(cert_handle, check_revocation, false,
808                                    cert_io_enabled, NULL, 0,
809                                    trust_anchors.get(), cvout);
810
811  if (status == SECSuccess &&
812      (flags & CertVerifier::VERIFY_REV_CHECKING_REQUIRED_LOCAL_ANCHORS) &&
813      !IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert)) {
814    // TODO(rsleevi): Optimize this by supplying the constructed chain to
815    // libpkix via cvin. Omitting for now, due to lack of coverage in upstream
816    // NSS tests for that feature.
817    scoped_cvout.Clear();
818    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
819    status = PKIXVerifyCert(cert_handle, true, true,
820                            cert_io_enabled, NULL, 0, trust_anchors.get(),
821                            cvout);
822  }
823
824  if (status == SECSuccess) {
825    AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
826                          cvout[cvout_trust_anchor_index].value.pointer.cert,
827                          &verify_result->public_key_hashes);
828
829    verify_result->is_issued_by_known_root =
830        IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
831    verify_result->is_issued_by_additional_trust_anchor =
832        IsAdditionalTrustAnchor(
833            trust_anchors.get(),
834            cvout[cvout_trust_anchor_index].value.pointer.cert);
835
836    GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
837                     cvout[cvout_trust_anchor_index].value.pointer.cert,
838                     verify_result);
839  }
840
841  CRLSetResult crl_set_result = kCRLSetUnknown;
842  if (crl_set) {
843    crl_set_result = CheckRevocationWithCRLSet(
844        cvout[cvout_cert_list_index].value.pointer.chain,
845        cvout[cvout_trust_anchor_index].value.pointer.cert,
846        crl_set);
847    if (crl_set_result == kCRLSetRevoked) {
848      PORT_SetError(SEC_ERROR_REVOKED_CERTIFICATE);
849      status = SECFailure;
850    }
851  }
852
853  if (status != SECSuccess) {
854    int err = PORT_GetError();
855    LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
856               << " failed err=" << err;
857    // CERT_PKIXVerifyCert rerports the wrong error code for
858    // expired certificates (NSS bug 491174)
859    if (err == SEC_ERROR_CERT_NOT_VALID &&
860        (verify_result->cert_status & CERT_STATUS_DATE_INVALID))
861      err = SEC_ERROR_EXPIRED_CERTIFICATE;
862    CertStatus cert_status = MapCertErrorToCertStatus(err);
863    if (cert_status) {
864      verify_result->cert_status |= cert_status;
865      return MapCertStatusToNetError(verify_result->cert_status);
866    }
867    // |err| is not a certificate error.
868    return MapSecurityError(err);
869  }
870
871  if (IsCertStatusError(verify_result->cert_status))
872    return MapCertStatusToNetError(verify_result->cert_status);
873
874  if ((flags & CertVerifier::VERIFY_EV_CERT) && is_ev_candidate) {
875    check_revocation |=
876        crl_set_result != kCRLSetOk &&
877        cert_io_enabled &&
878        (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY);
879    if (check_revocation)
880      verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
881
882    if (VerifyEV(cert_handle, flags, crl_set, check_revocation, metadata,
883                 ev_policy_oid, trust_anchors.get())) {
884      verify_result->cert_status |= CERT_STATUS_IS_EV;
885    }
886  }
887
888  return OK;
889}
890
891}  // namespace net
892