cert_verify_proc_nss.cc revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7
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_malloc<
41    CERTCertificatePolicies,
42    crypto::NSSDestroyer<CERTCertificatePolicies,
43                         CERT_DestroyCertificatePoliciesExtension> >
44    ScopedCERTCertificatePolicies;
45
46typedef scoped_ptr_malloc<
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 some element in
258//       the chain.
259//   kCRLSetOk: if every element in the chain is covered by a fresh CRLSet and
260//       is unrevoked.
261CRLSetResult CheckRevocationWithCRLSet(CERTCertList* cert_list,
262                                       CERTCertificate* root,
263                                       CRLSet* crl_set) {
264  std::vector<CERTCertificate*> certs;
265
266  if (cert_list) {
267    for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
268         !CERT_LIST_END(node, cert_list);
269         node = CERT_LIST_NEXT(node)) {
270      certs.push_back(node->cert);
271    }
272  }
273  if (root)
274    certs.push_back(root);
275
276  bool covered = true;
277
278  // We iterate from the root certificate down to the leaf, keeping track of
279  // the issuer's SPKI at each step.
280  std::string issuer_spki_hash;
281  for (std::vector<CERTCertificate*>::reverse_iterator i = certs.rbegin();
282       i != certs.rend(); ++i) {
283    CERTCertificate* cert = *i;
284
285    base::StringPiece der(reinterpret_cast<char*>(cert->derCert.data),
286                          cert->derCert.len);
287
288    base::StringPiece spki;
289    if (!asn1::ExtractSPKIFromDERCert(der, &spki)) {
290      NOTREACHED();
291      covered = false;
292      continue;
293    }
294    const std::string spki_hash = crypto::SHA256HashString(spki);
295
296    base::StringPiece serial_number = base::StringPiece(
297        reinterpret_cast<char*>(cert->serialNumber.data),
298        cert->serialNumber.len);
299
300    CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
301
302    if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
303      result = crl_set->CheckSerial(serial_number, issuer_spki_hash);
304
305    issuer_spki_hash = spki_hash;
306
307    switch (result) {
308      case CRLSet::REVOKED:
309        return kCRLSetRevoked;
310      case CRLSet::UNKNOWN:
311        covered = false;
312        continue;
313      case CRLSet::GOOD:
314        continue;
315      default:
316        NOTREACHED();
317        covered = false;
318        continue;
319    }
320  }
321
322  if (!covered || crl_set->IsExpired())
323    return kCRLSetUnknown;
324  return kCRLSetOk;
325}
326
327// Forward declarations.
328SECStatus RetryPKIXVerifyCertWithWorkarounds(
329    CERTCertificate* cert_handle, int num_policy_oids,
330    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
331    CERTValOutParam* cvout);
332SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle);
333
334// Call CERT_PKIXVerifyCert for the cert_handle.
335// Verification results are stored in an array of CERTValOutParam.
336// If |hard_fail| is true, and no policy_oids are supplied (eg: EV is NOT being
337// checked), then the failure to obtain valid CRL/OCSP information for all
338// certificates that contain CRL/OCSP URLs will cause the certificate to be
339// treated as if it was revoked. Since failures may be caused by transient
340// network failures or by malicious attackers, in general, hard_fail should be
341// false.
342// If policy_oids is not NULL and num_policy_oids is positive, policies
343// are also checked.
344// additional_trust_anchors is an optional list of certificates that can be
345// trusted as anchors when building a certificate chain.
346// Caller must initialize cvout before calling this function.
347SECStatus PKIXVerifyCert(CERTCertificate* cert_handle,
348                         bool check_revocation,
349                         bool hard_fail,
350                         bool cert_io_enabled,
351                         const SECOidTag* policy_oids,
352                         int num_policy_oids,
353                         CERTCertList* additional_trust_anchors,
354                         CERTChainVerifyCallback* chain_verify_callback,
355                         CERTValOutParam* cvout) {
356  bool use_crl = check_revocation;
357  bool use_ocsp = check_revocation;
358
359  PRUint64 revocation_method_flags =
360      CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
361      CERT_REV_M_ALLOW_NETWORK_FETCHING |
362      CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
363      CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
364      CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
365  PRUint64 revocation_method_independent_flags =
366      CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
367  if (check_revocation && policy_oids && num_policy_oids > 0) {
368    // EV verification requires revocation checking.  Consider the certificate
369    // revoked if we don't have revocation info.
370    // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
371    // verification or we want strict revocation flags.
372    revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
373    revocation_method_independent_flags |=
374        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
375  } else if (check_revocation && hard_fail) {
376    revocation_method_flags |= CERT_REV_M_FAIL_ON_MISSING_FRESH_INFO;
377    revocation_method_independent_flags |=
378        CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
379  } else {
380    revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
381    revocation_method_independent_flags |=
382        CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
383  }
384  PRUint64 method_flags[2];
385  method_flags[cert_revocation_method_crl] = revocation_method_flags;
386  method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
387
388  if (use_crl) {
389    method_flags[cert_revocation_method_crl] |=
390        CERT_REV_M_TEST_USING_THIS_METHOD;
391  }
392  if (use_ocsp) {
393    method_flags[cert_revocation_method_ocsp] |=
394        CERT_REV_M_TEST_USING_THIS_METHOD;
395  }
396
397  CERTRevocationMethodIndex preferred_revocation_methods[1];
398  if (use_ocsp) {
399    preferred_revocation_methods[0] = cert_revocation_method_ocsp;
400  } else {
401    preferred_revocation_methods[0] = cert_revocation_method_crl;
402  }
403
404  CERTRevocationFlags revocation_flags;
405  revocation_flags.leafTests.number_of_defined_methods =
406      arraysize(method_flags);
407  revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
408  revocation_flags.leafTests.number_of_preferred_methods =
409      arraysize(preferred_revocation_methods);
410  revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
411  revocation_flags.leafTests.cert_rev_method_independent_flags =
412      revocation_method_independent_flags;
413
414  revocation_flags.chainTests.number_of_defined_methods =
415      arraysize(method_flags);
416  revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
417  revocation_flags.chainTests.number_of_preferred_methods =
418      arraysize(preferred_revocation_methods);
419  revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
420  revocation_flags.chainTests.cert_rev_method_independent_flags =
421      revocation_method_independent_flags;
422
423
424  std::vector<CERTValInParam> cvin;
425  cvin.reserve(7);
426  CERTValInParam in_param;
427  in_param.type = cert_pi_revocationFlags;
428  in_param.value.pointer.revocation = &revocation_flags;
429  cvin.push_back(in_param);
430  if (policy_oids && num_policy_oids > 0) {
431    in_param.type = cert_pi_policyOID;
432    in_param.value.arraySize = num_policy_oids;
433    in_param.value.array.oids = policy_oids;
434    cvin.push_back(in_param);
435  }
436  if (additional_trust_anchors) {
437    in_param.type = cert_pi_trustAnchors;
438    in_param.value.pointer.chain = additional_trust_anchors;
439    cvin.push_back(in_param);
440    in_param.type = cert_pi_useOnlyTrustAnchors;
441    in_param.value.scalar.b = PR_FALSE;
442    cvin.push_back(in_param);
443  }
444  if (chain_verify_callback) {
445    in_param.type = cert_pi_chainVerifyCallback;
446    in_param.value.pointer.chainVerifyCallback = chain_verify_callback;
447    cvin.push_back(in_param);
448  }
449  in_param.type = cert_pi_end;
450  cvin.push_back(in_param);
451
452  SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
453                                     &cvin[0], cvout, NULL);
454  if (rv != SECSuccess) {
455    rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
456                                            cert_io_enabled, &cvin, cvout);
457  }
458  return rv;
459}
460
461// PKIXVerifyCert calls this function to work around some bugs in
462// CERT_PKIXVerifyCert.  All the arguments of this function are either the
463// arguments or local variables of PKIXVerifyCert.
464SECStatus RetryPKIXVerifyCertWithWorkarounds(
465    CERTCertificate* cert_handle, int num_policy_oids,
466    bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
467    CERTValOutParam* cvout) {
468  // We call this function when the first CERT_PKIXVerifyCert call in
469  // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
470  SECStatus rv = SECFailure;
471  int nss_error = PORT_GetError();
472  CERTValInParam in_param;
473
474  // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
475  // CA certificate, so we retry with cert_pi_useAIACertFetch.
476  // cert_pi_useAIACertFetch has several bugs in its error handling and
477  // error reporting (NSS bug 528743), so we don't use it by default.
478  // Note: When building a certificate chain, CERT_PKIXVerifyCert may
479  // incorrectly pick a CA certificate with the same subject name as the
480  // missing intermediate CA certificate, and  fail with the
481  // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
482  // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
483  if (cert_io_enabled &&
484      (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
485       nss_error == SEC_ERROR_BAD_SIGNATURE)) {
486    DCHECK_EQ(cvin->back().type,  cert_pi_end);
487    cvin->pop_back();
488    in_param.type = cert_pi_useAIACertFetch;
489    in_param.value.scalar.b = PR_TRUE;
490    cvin->push_back(in_param);
491    in_param.type = cert_pi_end;
492    cvin->push_back(in_param);
493    rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
494                             &(*cvin)[0], cvout, NULL);
495    if (rv == SECSuccess)
496      return rv;
497    int new_nss_error = PORT_GetError();
498    if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
499        new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
500        new_nss_error == SEC_ERROR_BAD_INFO_ACCESS_LOCATION ||
501        new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
502        new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
503        !IS_SEC_ERROR(new_nss_error)) {
504      // Use the original error code because of cert_pi_useAIACertFetch's
505      // bad error reporting.
506      PORT_SetError(nss_error);
507      return rv;
508    }
509    nss_error = new_nss_error;
510  }
511
512  // If an intermediate CA certificate has requireExplicitPolicy in its
513  // policyConstraints extension, CERT_PKIXVerifyCert fails with
514  // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
515  // certificate policy (NSS bug 552775).  So we retry with the certificate
516  // policy found in the server certificate.
517  if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
518      num_policy_oids == 0) {
519    SECOidTag policy = GetFirstCertPolicy(cert_handle);
520    if (policy != SEC_OID_UNKNOWN) {
521      DCHECK_EQ(cvin->back().type,  cert_pi_end);
522      cvin->pop_back();
523      in_param.type = cert_pi_policyOID;
524      in_param.value.arraySize = 1;
525      in_param.value.array.oids = &policy;
526      cvin->push_back(in_param);
527      in_param.type = cert_pi_end;
528      cvin->push_back(in_param);
529      rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
530                               &(*cvin)[0], cvout, NULL);
531      if (rv != SECSuccess) {
532        // Use the original error code.
533        PORT_SetError(nss_error);
534      }
535    }
536  }
537
538  return rv;
539}
540
541// Decodes the certificatePolicies extension of the certificate.  Returns
542// NULL if the certificate doesn't have the extension or the extension can't
543// be decoded.  The returned value must be freed with a
544// CERT_DestroyCertificatePoliciesExtension call.
545CERTCertificatePolicies* DecodeCertPolicies(
546    CERTCertificate* cert_handle) {
547  SECItem policy_ext;
548  SECStatus rv = CERT_FindCertExtension(cert_handle,
549                                        SEC_OID_X509_CERTIFICATE_POLICIES,
550                                        &policy_ext);
551  if (rv != SECSuccess)
552    return NULL;
553  CERTCertificatePolicies* policies =
554      CERT_DecodeCertificatePoliciesExtension(&policy_ext);
555  SECITEM_FreeItem(&policy_ext, PR_FALSE);
556  return policies;
557}
558
559// Returns the OID tag for the first certificate policy in the certificate's
560// certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
561// has no certificate policy.
562SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle) {
563  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
564  if (!policies.get())
565    return SEC_OID_UNKNOWN;
566
567  CERTPolicyInfo* policy_info = policies->policyInfos[0];
568  if (!policy_info)
569    return SEC_OID_UNKNOWN;
570  if (policy_info->oid != SEC_OID_UNKNOWN)
571    return policy_info->oid;
572
573  // The certificate policy is unknown to NSS.  We need to create a dynamic
574  // OID tag for the policy.
575  SECOidData od;
576  od.oid.len = policy_info->policyID.len;
577  od.oid.data = policy_info->policyID.data;
578  od.offset = SEC_OID_UNKNOWN;
579  // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
580  // default description here.  The description doesn't need to be unique for
581  // each OID.
582  od.desc = "a certificate policy";
583  od.mechanism = CKM_INVALID_MECHANISM;
584  od.supportedExtension = INVALID_CERT_EXTENSION;
585  return SECOID_AddEntry(&od);
586}
587
588HashValue CertPublicKeyHashSHA1(CERTCertificate* cert) {
589  HashValue hash(HASH_VALUE_SHA1);
590#if defined(OS_IOS)
591  CC_SHA1(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
592#else
593  SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data(),
594                              cert->derPublicKey.data, cert->derPublicKey.len);
595  DCHECK_EQ(SECSuccess, rv);
596#endif
597  return hash;
598}
599
600HashValue CertPublicKeyHashSHA256(CERTCertificate* cert) {
601  HashValue hash(HASH_VALUE_SHA256);
602#if defined(OS_IOS)
603  CC_SHA256(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
604#else
605  SECStatus rv = HASH_HashBuf(HASH_AlgSHA256, hash.data(),
606                              cert->derPublicKey.data, cert->derPublicKey.len);
607  DCHECK_EQ(rv, SECSuccess);
608#endif
609  return hash;
610}
611
612void AppendPublicKeyHashes(CERTCertList* cert_list,
613                           CERTCertificate* root_cert,
614                           HashValueVector* hashes) {
615  for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
616       !CERT_LIST_END(node, cert_list);
617       node = CERT_LIST_NEXT(node)) {
618    hashes->push_back(CertPublicKeyHashSHA1(node->cert));
619    hashes->push_back(CertPublicKeyHashSHA256(node->cert));
620  }
621  if (root_cert) {
622    hashes->push_back(CertPublicKeyHashSHA1(root_cert));
623    hashes->push_back(CertPublicKeyHashSHA256(root_cert));
624  }
625}
626
627// Returns true if |cert_handle| contains a policy OID that is an EV policy
628// OID according to |metadata|, storing the resulting policy OID in
629// |*ev_policy_oid|. A true return is not sufficient to establish that a
630// certificate is EV, but a false return is sufficient to establish the
631// certificate cannot be EV.
632bool IsEVCandidate(EVRootCAMetadata* metadata,
633                   CERTCertificate* cert_handle,
634                   SECOidTag* ev_policy_oid) {
635  DCHECK(cert_handle);
636  ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
637  if (!policies.get())
638    return false;
639
640  CERTPolicyInfo** policy_infos = policies->policyInfos;
641  while (*policy_infos != NULL) {
642    CERTPolicyInfo* policy_info = *policy_infos++;
643    // If the Policy OID is unknown, that implicitly means it has not been
644    // registered as an EV policy.
645    if (policy_info->oid == SEC_OID_UNKNOWN)
646      continue;
647    if (metadata->IsEVPolicyOID(policy_info->oid)) {
648      *ev_policy_oid = policy_info->oid;
649      return true;
650    }
651  }
652
653  return false;
654}
655
656// Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
657// and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
658// TODO(wtc): A possible optimization is that we get the trust anchor from
659// the first PKIXVerifyCert call.  We look up the EV policy for the trust
660// anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
661// Otherwise, we pass just that EV policy (as opposed to all the EV policies)
662// to the second PKIXVerifyCert call.
663bool VerifyEV(CERTCertificate* cert_handle,
664              int flags,
665              CRLSet* crl_set,
666              bool rev_checking_enabled,
667              EVRootCAMetadata* metadata,
668              SECOidTag ev_policy_oid,
669              CERTCertList* additional_trust_anchors,
670              CERTChainVerifyCallback* chain_verify_callback) {
671  CERTValOutParam cvout[3];
672  int cvout_index = 0;
673  cvout[cvout_index].type = cert_po_certList;
674  cvout[cvout_index].value.pointer.chain = NULL;
675  int cvout_cert_list_index = cvout_index;
676  cvout_index++;
677  cvout[cvout_index].type = cert_po_trustAnchor;
678  cvout[cvout_index].value.pointer.cert = NULL;
679  int cvout_trust_anchor_index = cvout_index;
680  cvout_index++;
681  cvout[cvout_index].type = cert_po_end;
682  ScopedCERTValOutParam scoped_cvout(cvout);
683
684  SECStatus status = PKIXVerifyCert(
685      cert_handle,
686      rev_checking_enabled,
687      true, /* hard fail is implied in EV. */
688      flags & CertVerifier::VERIFY_CERT_IO_ENABLED,
689      &ev_policy_oid,
690      1,
691      additional_trust_anchors,
692      chain_verify_callback,
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  return true;
747}
748
749int CertVerifyProcNSS::VerifyInternalImpl(
750    X509Certificate* cert,
751    const std::string& hostname,
752    int flags,
753    CRLSet* crl_set,
754    const CertificateList& additional_trust_anchors,
755    CERTChainVerifyCallback* chain_verify_callback,
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  if (!cert->VerifyNameMatch(hostname,
767                             &verify_result->common_name_fallback_used)) {
768    verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
769  }
770
771  // Make sure that the cert is valid now.
772  SECCertTimeValidity validity = CERT_CheckCertValidTimes(
773      cert_handle, PR_Now(), PR_TRUE);
774  if (validity != secCertTimeValid)
775    verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
776
777  CERTValOutParam cvout[3];
778  int cvout_index = 0;
779  cvout[cvout_index].type = cert_po_certList;
780  cvout[cvout_index].value.pointer.chain = NULL;
781  int cvout_cert_list_index = cvout_index;
782  cvout_index++;
783  cvout[cvout_index].type = cert_po_trustAnchor;
784  cvout[cvout_index].value.pointer.cert = NULL;
785  int cvout_trust_anchor_index = cvout_index;
786  cvout_index++;
787  cvout[cvout_index].type = cert_po_end;
788  ScopedCERTValOutParam scoped_cvout(cvout);
789
790  EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
791  SECOidTag ev_policy_oid = SEC_OID_UNKNOWN;
792  bool is_ev_candidate =
793      (flags & CertVerifier::VERIFY_EV_CERT) &&
794      IsEVCandidate(metadata, cert_handle, &ev_policy_oid);
795  bool cert_io_enabled = flags & CertVerifier::VERIFY_CERT_IO_ENABLED;
796  bool check_revocation =
797      cert_io_enabled &&
798      (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED);
799  if (check_revocation)
800    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
801
802  ScopedCERTCertList trust_anchors;
803  if (!additional_trust_anchors.empty()) {
804    trust_anchors.reset(
805        CertificateListToCERTCertList(additional_trust_anchors));
806  }
807
808  SECStatus status = PKIXVerifyCert(cert_handle,
809                                    check_revocation,
810                                    false,
811                                    cert_io_enabled,
812                                    NULL,
813                                    0,
814                                    trust_anchors.get(),
815                                    chain_verify_callback,
816                                    cvout);
817
818  if (status == SECSuccess &&
819      (flags & CertVerifier::VERIFY_REV_CHECKING_REQUIRED_LOCAL_ANCHORS) &&
820      !IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert)) {
821    // TODO(rsleevi): Optimize this by supplying the constructed chain to
822    // libpkix via cvin. Omitting for now, due to lack of coverage in upstream
823    // NSS tests for that feature.
824    scoped_cvout.Clear();
825    verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
826    status = PKIXVerifyCert(cert_handle,
827                            true,
828                            true,
829                            cert_io_enabled,
830                            NULL,
831                            0,
832                            trust_anchors.get(),
833                            chain_verify_callback,
834                            cvout);
835  }
836
837  if (status == SECSuccess) {
838    AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
839                          cvout[cvout_trust_anchor_index].value.pointer.cert,
840                          &verify_result->public_key_hashes);
841
842    verify_result->is_issued_by_known_root =
843        IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
844    verify_result->is_issued_by_additional_trust_anchor =
845        IsAdditionalTrustAnchor(
846            trust_anchors.get(),
847            cvout[cvout_trust_anchor_index].value.pointer.cert);
848
849    GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
850                     cvout[cvout_trust_anchor_index].value.pointer.cert,
851                     verify_result);
852  }
853
854  CRLSetResult crl_set_result = kCRLSetUnknown;
855  if (crl_set) {
856    crl_set_result = CheckRevocationWithCRLSet(
857        cvout[cvout_cert_list_index].value.pointer.chain,
858        cvout[cvout_trust_anchor_index].value.pointer.cert,
859        crl_set);
860    if (crl_set_result == kCRLSetRevoked) {
861      PORT_SetError(SEC_ERROR_REVOKED_CERTIFICATE);
862      status = SECFailure;
863    }
864  }
865
866  if (status != SECSuccess) {
867    int err = PORT_GetError();
868    LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
869               << " failed err=" << err;
870    // CERT_PKIXVerifyCert rerports the wrong error code for
871    // expired certificates (NSS bug 491174)
872    if (err == SEC_ERROR_CERT_NOT_VALID &&
873        (verify_result->cert_status & CERT_STATUS_DATE_INVALID))
874      err = SEC_ERROR_EXPIRED_CERTIFICATE;
875    CertStatus cert_status = MapCertErrorToCertStatus(err);
876    if (cert_status) {
877      verify_result->cert_status |= cert_status;
878      return MapCertStatusToNetError(verify_result->cert_status);
879    }
880    // |err| is not a certificate error.
881    return MapSecurityError(err);
882  }
883
884  if (IsCertStatusError(verify_result->cert_status))
885    return MapCertStatusToNetError(verify_result->cert_status);
886
887  if ((flags & CertVerifier::VERIFY_EV_CERT) && is_ev_candidate) {
888    check_revocation |=
889        crl_set_result != kCRLSetOk &&
890        cert_io_enabled &&
891        (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY);
892    if (check_revocation)
893      verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
894
895    if (VerifyEV(cert_handle,
896                 flags,
897                 crl_set,
898                 check_revocation,
899                 metadata,
900                 ev_policy_oid,
901                 trust_anchors.get(),
902                 chain_verify_callback)) {
903      verify_result->cert_status |= CERT_STATUS_IS_EV;
904    }
905  }
906
907  return OK;
908}
909
910int CertVerifyProcNSS::VerifyInternal(
911    X509Certificate* cert,
912    const std::string& hostname,
913    int flags,
914    CRLSet* crl_set,
915    const CertificateList& additional_trust_anchors,
916    CertVerifyResult* verify_result) {
917  return VerifyInternalImpl(cert,
918                            hostname,
919                            flags,
920                            crl_set,
921                            additional_trust_anchors,
922                            NULL,  // chain_verify_callback
923                            verify_result);
924}
925
926}  // namespace net
927