Add m-esr52 at 52.6.0

14 files changed, 6920 insertions, 0 deletions

diff --git a/security/pkix/lib/ScopedPtr.h b/security/pkix/lib/ScopedPtr.h
new file mode 100644
index 000000000..a9e18adc1
--- /dev/null
+++ b/security/pkix/lib/ScopedPtr.h
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef mozilla_pkix_ScopedPtr_h
+#define mozilla_pkix_ScopedPtr_h
+
+namespace mozilla { namespace pkix {
+
+// A subset polyfill of std::unique_ptr that does not support move construction
+// or move assignment. This is used instead of std::unique_ptr because some
+// important toolchains still don't provide std::unique_ptr, including in
+// particular Android NDK projects with APP_STL=stlport_static or
+// ALL_STL=stlport_shared.
+template <typename T, void (&Destroyer)(T*)>
+class ScopedPtr final
+{
+public:
+  explicit ScopedPtr(T* value = nullptr) : mValue(value) { }
+
+  ScopedPtr(const ScopedPtr&) = delete;
+
+  ~ScopedPtr()
+  {
+    if (mValue) {
+      Destroyer(mValue);
+    }
+  }
+
+  void operator=(const ScopedPtr&) = delete;
+
+  T& operator*() const { return *mValue; }
+  T* operator->() const { return mValue; }
+
+  explicit operator bool() const { return mValue; }
+
+  T* get() const { return mValue; }
+
+  T* release()
+  {
+    T* result = mValue;
+    mValue = nullptr;
+    return result;
+  }
+
+  void reset(T* newValue = nullptr)
+  {
+    // The C++ standard requires std::unique_ptr to destroy the old value
+    // pointed to by mValue, if any, *after* assigning the new value to mValue.
+    T* oldValue = mValue;
+    mValue = newValue;
+    if (oldValue) {
+      Destroyer(oldValue);
+    }
+  }
+
+private:
+  T* mValue;
+};
+
+} } // namespace mozilla::pkix
+
+#endif // mozilla_pkix_ScopedPtr_h
diff --git a/security/pkix/lib/pkixbuild.cpp b/security/pkix/lib/pkixbuild.cpp
new file mode 100644
index 000000000..fdbd9b59f
--- /dev/null
+++ b/security/pkix/lib/pkixbuild.cpp
@@ -0,0 +1,382 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkix/pkix.h"
+
+#include "pkixcheck.h"
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix {
+
+static Result BuildForward(TrustDomain& trustDomain,
+                           const BackCert& subject,
+                           Time time,
+                           KeyUsage requiredKeyUsageIfPresent,
+                           KeyPurposeId requiredEKUIfPresent,
+                           const CertPolicyId& requiredPolicy,
+                           /*optional*/ const Input* stapledOCSPResponse,
+                           unsigned int subCACount);
+
+TrustDomain::IssuerChecker::IssuerChecker() { }
+TrustDomain::IssuerChecker::~IssuerChecker() { }
+
+// The implementation of TrustDomain::IssuerTracker is in a subclass only to
+// hide the implementation from external users.
+class PathBuildingStep final : public TrustDomain::IssuerChecker
+{
+public:
+  PathBuildingStep(TrustDomain& trustDomain, const BackCert& subject,
+                   Time time, KeyPurposeId requiredEKUIfPresent,
+                   const CertPolicyId& requiredPolicy,
+                   /*optional*/ const Input* stapledOCSPResponse,
+                   unsigned int subCACount, Result deferredSubjectError)
+    : trustDomain(trustDomain)
+    , subject(subject)
+    , time(time)
+    , requiredEKUIfPresent(requiredEKUIfPresent)
+    , requiredPolicy(requiredPolicy)
+    , stapledOCSPResponse(stapledOCSPResponse)
+    , subCACount(subCACount)
+    , deferredSubjectError(deferredSubjectError)
+    , result(Result::FATAL_ERROR_LIBRARY_FAILURE)
+    , resultWasSet(false)
+  {
+  }
+
+  Result Check(Input potentialIssuerDER,
+               /*optional*/ const Input* additionalNameConstraints,
+               /*out*/ bool& keepGoing) override;
+
+  Result CheckResult() const;
+
+private:
+  TrustDomain& trustDomain;
+  const BackCert& subject;
+  const Time time;
+  const KeyPurposeId requiredEKUIfPresent;
+  const CertPolicyId& requiredPolicy;
+  /*optional*/ Input const* const stapledOCSPResponse;
+  const unsigned int subCACount;
+  const Result deferredSubjectError;
+
+  // Initialized lazily.
+  uint8_t subjectSignatureDigestBuf[MAX_DIGEST_SIZE_IN_BYTES];
+  der::PublicKeyAlgorithm subjectSignaturePublicKeyAlg;
+  SignedDigest subjectSignature;
+
+  Result RecordResult(Result currentResult, /*out*/ bool& keepGoing);
+  Result result;
+  bool resultWasSet;
+
+  PathBuildingStep(const PathBuildingStep&) = delete;
+  void operator=(const PathBuildingStep&) = delete;
+};
+
+Result
+PathBuildingStep::RecordResult(Result newResult, /*out*/ bool& keepGoing)
+{
+  if (newResult == Result::ERROR_UNTRUSTED_CERT) {
+    newResult = Result::ERROR_UNTRUSTED_ISSUER;
+  } else if (newResult == Result::ERROR_EXPIRED_CERTIFICATE) {
+    newResult = Result::ERROR_EXPIRED_ISSUER_CERTIFICATE;
+  } else if (newResult == Result::ERROR_NOT_YET_VALID_CERTIFICATE) {
+    newResult = Result::ERROR_NOT_YET_VALID_ISSUER_CERTIFICATE;
+  }
+
+  if (resultWasSet) {
+    if (result == Success) {
+      return NotReached("RecordResult called after finding a chain",
+                        Result::FATAL_ERROR_INVALID_STATE);
+    }
+    // If every potential issuer has the same problem (e.g. expired) and/or if
+    // there is only one bad potential issuer, then return a more specific
+    // error. Otherwise, punt on trying to decide which error should be
+    // returned by returning the generic Result::ERROR_UNKNOWN_ISSUER error.
+    if (newResult != Success && newResult != result) {
+      newResult = Result::ERROR_UNKNOWN_ISSUER;
+    }
+  }
+
+  result = newResult;
+  resultWasSet = true;
+  keepGoing = result != Success;
+  return Success;
+}
+
+Result
+PathBuildingStep::CheckResult() const
+{
+  if (!resultWasSet) {
+    return Result::ERROR_UNKNOWN_ISSUER;
+  }
+  return result;
+}
+
+// The code that executes in the inner loop of BuildForward
+Result
+PathBuildingStep::Check(Input potentialIssuerDER,
+           /*optional*/ const Input* additionalNameConstraints,
+                /*out*/ bool& keepGoing)
+{
+  BackCert potentialIssuer(potentialIssuerDER, EndEntityOrCA::MustBeCA,
+                           &subject);
+  Result rv = potentialIssuer.Init();
+  if (rv != Success) {
+    return RecordResult(rv, keepGoing);
+  }
+
+  // Simple TrustDomain::FindIssuers implementations may pass in all possible
+  // CA certificates without any filtering. Because of this, we don't consider
+  // a mismatched name to be an error. Instead, we just pretend that any
+  // certificate without a matching name was never passed to us. In particular,
+  // we treat the case where the TrustDomain only asks us to check CA
+  // certificates with mismatched names as equivalent to the case where the
+  // TrustDomain never called Check() at all.
+  if (!InputsAreEqual(potentialIssuer.GetSubject(), subject.GetIssuer())) {
+    keepGoing = true;
+    return Success;
+  }
+
+  // Loop prevention, done as recommended by RFC4158 Section 5.2
+  // TODO: this doesn't account for subjectAltNames!
+  // TODO(perf): This probably can and should be optimized in some way.
+  bool loopDetected = false;
+  for (const BackCert* prev = potentialIssuer.childCert;
+       !loopDetected && prev != nullptr; prev = prev->childCert) {
+    if (InputsAreEqual(potentialIssuer.GetSubjectPublicKeyInfo(),
+                       prev->GetSubjectPublicKeyInfo()) &&
+        InputsAreEqual(potentialIssuer.GetSubject(), prev->GetSubject())) {
+      // XXX: error code
+      return RecordResult(Result::ERROR_UNKNOWN_ISSUER, keepGoing);
+    }
+  }
+
+  if (potentialIssuer.GetNameConstraints()) {
+    rv = CheckNameConstraints(*potentialIssuer.GetNameConstraints(),
+                              subject, requiredEKUIfPresent);
+    if (rv != Success) {
+       return RecordResult(rv, keepGoing);
+    }
+  }
+
+  if (additionalNameConstraints) {
+    rv = CheckNameConstraints(*additionalNameConstraints, subject,
+                              requiredEKUIfPresent);
+    if (rv != Success) {
+       return RecordResult(rv, keepGoing);
+    }
+  }
+
+  rv = CheckTLSFeatures(subject, potentialIssuer);
+  if (rv != Success) {
+    return RecordResult(rv, keepGoing);
+  }
+
+  // RFC 5280, Section 4.2.1.3: "If the keyUsage extension is present, then the
+  // subject public key MUST NOT be used to verify signatures on certificates
+  // or CRLs unless the corresponding keyCertSign or cRLSign bit is set."
+  rv = BuildForward(trustDomain, potentialIssuer, time, KeyUsage::keyCertSign,
+                    requiredEKUIfPresent, requiredPolicy, nullptr, subCACount);
+  if (rv != Success) {
+    return RecordResult(rv, keepGoing);
+  }
+
+  // Calculate the digest of the subject's signed data if we haven't already
+  // done so. We do this lazily to avoid doing it at all if we backtrack before
+  // getting to this point. We cache the result to avoid recalculating it if we
+  // backtrack after getting to this point.
+  if (subjectSignature.digest.GetLength() == 0) {
+    rv = DigestSignedData(trustDomain, subject.GetSignedData(),
+                          subjectSignatureDigestBuf,
+                          subjectSignaturePublicKeyAlg, subjectSignature);
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  rv = VerifySignedDigest(trustDomain, subjectSignaturePublicKeyAlg,
+                          subjectSignature,
+                          potentialIssuer.GetSubjectPublicKeyInfo());
+  if (rv != Success) {
+    return RecordResult(rv, keepGoing);
+  }
+
+  // We avoid doing revocation checking for expired certificates because OCSP
+  // responders are allowed to forget about expired certificates, and many OCSP
+  // responders return an error when asked for the status of an expired
+  // certificate.
+  if (deferredSubjectError != Result::ERROR_EXPIRED_CERTIFICATE) {
+    CertID certID(subject.GetIssuer(), potentialIssuer.GetSubjectPublicKeyInfo(),
+                  subject.GetSerialNumber());
+    Time notBefore(Time::uninitialized);
+    Time notAfter(Time::uninitialized);
+    // This should never fail. If we're here, we've already parsed the validity
+    // and checked that the given time is in the certificate's validity period.
+    rv = ParseValidity(subject.GetValidity(), &notBefore, &notAfter);
+    if (rv != Success) {
+      return rv;
+    }
+    Duration validityDuration(notAfter, notBefore);
+    rv = trustDomain.CheckRevocation(subject.endEntityOrCA, certID, time,
+                                     validityDuration, stapledOCSPResponse,
+                                     subject.GetAuthorityInfoAccess());
+    if (rv != Success) {
+      return RecordResult(rv, keepGoing);
+    }
+
+    if (subject.endEntityOrCA == EndEntityOrCA::MustBeEndEntity) {
+      const Input* sctExtension = subject.GetSignedCertificateTimestamps();
+      if (sctExtension) {
+        Input sctList;
+        rv = ExtractSignedCertificateTimestampListFromExtension(*sctExtension,
+                                                                sctList);
+        if (rv != Success) {
+          return RecordResult(rv, keepGoing);
+        }
+        trustDomain.NoteAuxiliaryExtension(AuxiliaryExtension::EmbeddedSCTList,
+                                           sctList);
+      }
+    }
+  }
+
+  return RecordResult(Success, keepGoing);
+}
+
+// Recursively build the path from the given subject certificate to the root.
+//
+// Be very careful about changing the order of checks. The order is significant
+// because it affects which error we return when a certificate or certificate
+// chain has multiple problems. See the error ranking documentation in
+// pkix/pkix.h.
+static Result
+BuildForward(TrustDomain& trustDomain,
+             const BackCert& subject,
+             Time time,
+             KeyUsage requiredKeyUsageIfPresent,
+             KeyPurposeId requiredEKUIfPresent,
+             const CertPolicyId& requiredPolicy,
+             /*optional*/ const Input* stapledOCSPResponse,
+             unsigned int subCACount)
+{
+  Result rv;
+
+  TrustLevel trustLevel;
+  // If this is an end-entity and not a trust anchor, we defer reporting
+  // any error found here until after attempting to find a valid chain.
+  // See the explanation of error prioritization in pkix.h.
+  rv = CheckIssuerIndependentProperties(trustDomain, subject, time,
+                                        requiredKeyUsageIfPresent,
+                                        requiredEKUIfPresent, requiredPolicy,
+                                        subCACount, trustLevel);
+  Result deferredEndEntityError = Success;
+  if (rv != Success) {
+    if (subject.endEntityOrCA == EndEntityOrCA::MustBeEndEntity &&
+        trustLevel != TrustLevel::TrustAnchor) {
+      deferredEndEntityError = rv;
+    } else {
+      return rv;
+    }
+  }
+
+  if (trustLevel == TrustLevel::TrustAnchor) {
+    // End of the recursion.
+
+    NonOwningDERArray chain;
+    for (const BackCert* cert = &subject; cert; cert = cert->childCert) {
+      rv = chain.Append(cert->GetDER());
+      if (rv != Success) {
+        return NotReached("NonOwningDERArray::SetItem failed.", rv);
+      }
+    }
+
+    // This must be done here, after the chain is built but before any
+    // revocation checks have been done.
+    return trustDomain.IsChainValid(chain, time);
+  }
+
+  if (subject.endEntityOrCA == EndEntityOrCA::MustBeCA) {
+    // Avoid stack overflows and poor performance by limiting cert chain
+    // length.
+    static const unsigned int MAX_SUBCA_COUNT = 6;
+    static_assert(1/*end-entity*/ + MAX_SUBCA_COUNT + 1/*root*/ ==
+                  NonOwningDERArray::MAX_LENGTH,
+                  "MAX_SUBCA_COUNT and NonOwningDERArray::MAX_LENGTH mismatch.");
+    if (subCACount >= MAX_SUBCA_COUNT) {
+      return Result::ERROR_UNKNOWN_ISSUER;
+    }
+    ++subCACount;
+  } else {
+    assert(subCACount == 0);
+  }
+
+  // Find a trusted issuer.
+
+  PathBuildingStep pathBuilder(trustDomain, subject, time,
+                               requiredEKUIfPresent, requiredPolicy,
+                               stapledOCSPResponse, subCACount,
+                               deferredEndEntityError);
+
+  // TODO(bug 965136): Add SKI/AKI matching optimizations
+  rv = trustDomain.FindIssuer(subject.GetIssuer(), pathBuilder, time);
+  if (rv != Success) {
+    return rv;
+  }
+
+  rv = pathBuilder.CheckResult();
+  if (rv != Success) {
+    return rv;
+  }
+
+  // If we found a valid chain but deferred reporting an error with the
+  // end-entity certificate, report it now.
+  if (deferredEndEntityError != Success) {
+    return deferredEndEntityError;
+  }
+
+  // We've built a valid chain from the subject cert up to a trusted root.
+  return Success;
+}
+
+Result
+BuildCertChain(TrustDomain& trustDomain, Input certDER,
+               Time time, EndEntityOrCA endEntityOrCA,
+               KeyUsage requiredKeyUsageIfPresent,
+               KeyPurposeId requiredEKUIfPresent,
+               const CertPolicyId& requiredPolicy,
+               /*optional*/ const Input* stapledOCSPResponse)
+{
+  // XXX: Support the legacy use of the subject CN field for indicating the
+  // domain name the certificate is valid for.
+  BackCert cert(certDER, endEntityOrCA, nullptr);
+  Result rv = cert.Init();
+  if (rv != Success) {
+    return rv;
+  }
+
+  return BuildForward(trustDomain, cert, time, requiredKeyUsageIfPresent,
+                      requiredEKUIfPresent, requiredPolicy, stapledOCSPResponse,
+                      0/*subCACount*/);
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixcert.cpp b/security/pkix/lib/pkixcert.cpp
new file mode 100644
index 000000000..ffa58fd3b
--- /dev/null
+++ b/security/pkix/lib/pkixcert.cpp
@@ -0,0 +1,323 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2014 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix {
+
+Result
+BackCert::Init()
+{
+  Result rv;
+
+  // Certificate  ::=  SEQUENCE  {
+  //         tbsCertificate       TBSCertificate,
+  //         signatureAlgorithm   AlgorithmIdentifier,
+  //         signatureValue       BIT STRING  }
+
+  Reader tbsCertificate;
+
+  // The scope of |input| and |certificate| are limited to this block so we
+  // don't accidentally confuse them for tbsCertificate later.
+  {
+    Reader certificate;
+    rv = der::ExpectTagAndGetValueAtEnd(der, der::SEQUENCE, certificate);
+    if (rv != Success) {
+      return rv;
+    }
+    rv = der::SignedData(certificate, tbsCertificate, signedData);
+    if (rv != Success) {
+      return rv;
+    }
+    rv = der::End(certificate);
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  // TBSCertificate  ::=  SEQUENCE  {
+  //      version         [0]  EXPLICIT Version DEFAULT v1,
+  //      serialNumber         CertificateSerialNumber,
+  //      signature            AlgorithmIdentifier,
+  //      issuer               Name,
+  //      validity             Validity,
+  //      subject              Name,
+  //      subjectPublicKeyInfo SubjectPublicKeyInfo,
+  //      issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
+  //                           -- If present, version MUST be v2 or v3
+  //      subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
+  //                           -- If present, version MUST be v2 or v3
+  //      extensions      [3]  EXPLICIT Extensions OPTIONAL
+  //                           -- If present, version MUST be v3
+  //      }
+  rv = der::OptionalVersion(tbsCertificate, version);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::CertificateSerialNumber(tbsCertificate, serialNumber);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::ExpectTagAndGetValue(tbsCertificate, der::SEQUENCE, signature);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::ExpectTagAndGetTLV(tbsCertificate, der::SEQUENCE, issuer);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::ExpectTagAndGetValue(tbsCertificate, der::SEQUENCE, validity);
+  if (rv != Success) {
+    return rv;
+  }
+  // TODO(bug XXXXXXX): We rely on the the caller of mozilla::pkix to validate
+  // that the name is syntactically valid, if they care. In Gecko we do this
+  // implicitly by parsing the certificate into a CERTCertificate object.
+  // Instead of relying on the caller to do this, we should do it ourselves.
+  rv = der::ExpectTagAndGetTLV(tbsCertificate, der::SEQUENCE, subject);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::ExpectTagAndGetTLV(tbsCertificate, der::SEQUENCE,
+                               subjectPublicKeyInfo);
+  if (rv != Success) {
+    return rv;
+  }
+
+  static const uint8_t CSC = der::CONTEXT_SPECIFIC | der::CONSTRUCTED;
+
+  // According to RFC 5280, all fields below this line are forbidden for
+  // certificate versions less than v3.  However, for compatibility reasons,
+  // we parse v1/v2 certificates in the same way as v3 certificates.  So if
+  // these fields appear in a v1 certificate, they will be used.
+
+  // Ignore issuerUniqueID if present.
+  if (tbsCertificate.Peek(CSC | 1)) {
+    rv = der::ExpectTagAndSkipValue(tbsCertificate, CSC | 1);
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  // Ignore subjectUniqueID if present.
+  if (tbsCertificate.Peek(CSC | 2)) {
+    rv = der::ExpectTagAndSkipValue(tbsCertificate, CSC | 2);
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  rv = der::OptionalExtensions(
+         tbsCertificate, CSC | 3,
+         [this](Reader& extnID, const Input& extnValue, bool critical,
+                /*out*/ bool& understood) {
+           return RememberExtension(extnID, extnValue, critical, understood);
+         });
+  if (rv != Success) {
+    return rv;
+  }
+
+  // The Netscape Certificate Type extension is an obsolete
+  // Netscape-proprietary mechanism that we ignore in favor of the standard
+  // extensions. However, some CAs have issued certificates with the Netscape
+  // Cert Type extension marked critical. Thus, for compatibility reasons, we
+  // "understand" this extension by ignoring it when it is not critical, and
+  // by ensuring that the equivalent standardized extensions are present when
+  // it is marked critical, based on the assumption that the information in
+  // the Netscape Cert Type extension is consistent with the information in
+  // the standard extensions.
+  //
+  // Here is a mapping between the Netscape Cert Type extension and the
+  // standard extensions:
+  //
+  // Netscape Cert Type  |  BasicConstraints.cA  |  Extended Key Usage
+  // --------------------+-----------------------+----------------------
+  // SSL Server          |  false                |  id_kp_serverAuth
+  // SSL Client          |  false                |  id_kp_clientAuth
+  // S/MIME Client       |  false                |  id_kp_emailProtection
+  // Object Signing      |  false                |  id_kp_codeSigning
+  // SSL Server CA       |  true                 |  id_pk_serverAuth
+  // SSL Client CA       |  true                 |  id_kp_clientAuth
+  // S/MIME CA           |  true                 |  id_kp_emailProtection
+  // Object Signing CA   |  true                 |  id_kp_codeSigning
+  if (criticalNetscapeCertificateType.GetLength() > 0 &&
+      (basicConstraints.GetLength() == 0 || extKeyUsage.GetLength() == 0)) {
+    return Result::ERROR_UNKNOWN_CRITICAL_EXTENSION;
+  }
+
+  return der::End(tbsCertificate);
+}
+
+Result
+BackCert::RememberExtension(Reader& extnID, Input extnValue,
+                            bool critical, /*out*/ bool& understood)
+{
+  understood = false;
+
+  // python DottedOIDToCode.py id-ce-keyUsage 2.5.29.15
+  static const uint8_t id_ce_keyUsage[] = {
+    0x55, 0x1d, 0x0f
+  };
+  // python DottedOIDToCode.py id-ce-subjectAltName 2.5.29.17
+  static const uint8_t id_ce_subjectAltName[] = {
+    0x55, 0x1d, 0x11
+  };
+  // python DottedOIDToCode.py id-ce-basicConstraints 2.5.29.19
+  static const uint8_t id_ce_basicConstraints[] = {
+    0x55, 0x1d, 0x13
+  };
+  // python DottedOIDToCode.py id-ce-nameConstraints 2.5.29.30
+  static const uint8_t id_ce_nameConstraints[] = {
+    0x55, 0x1d, 0x1e
+  };
+  // python DottedOIDToCode.py id-ce-certificatePolicies 2.5.29.32
+  static const uint8_t id_ce_certificatePolicies[] = {
+    0x55, 0x1d, 0x20
+  };
+  // python DottedOIDToCode.py id-ce-policyConstraints 2.5.29.36
+  static const uint8_t id_ce_policyConstraints[] = {
+    0x55, 0x1d, 0x24
+  };
+  // python DottedOIDToCode.py id-ce-extKeyUsage 2.5.29.37
+  static const uint8_t id_ce_extKeyUsage[] = {
+    0x55, 0x1d, 0x25
+  };
+  // python DottedOIDToCode.py id-ce-inhibitAnyPolicy 2.5.29.54
+  static const uint8_t id_ce_inhibitAnyPolicy[] = {
+    0x55, 0x1d, 0x36
+  };
+  // python DottedOIDToCode.py id-pe-authorityInfoAccess 1.3.6.1.5.5.7.1.1
+  static const uint8_t id_pe_authorityInfoAccess[] = {
+    0x2b, 0x06, 0x01, 0x05, 0x05, 0x07, 0x01, 0x01
+  };
+  // python DottedOIDToCode.py id-pkix-ocsp-nocheck 1.3.6.1.5.5.7.48.1.5
+  static const uint8_t id_pkix_ocsp_nocheck[] = {
+    0x2b, 0x06, 0x01, 0x05, 0x05, 0x07, 0x30, 0x01, 0x05
+  };
+  // python DottedOIDToCode.py Netscape-certificate-type 2.16.840.1.113730.1.1
+  static const uint8_t Netscape_certificate_type[] = {
+    0x60, 0x86, 0x48, 0x01, 0x86, 0xf8, 0x42, 0x01, 0x01
+  };
+  // python DottedOIDToCode.py id-pe-tlsfeature 1.3.6.1.5.5.7.1.24
+  static const uint8_t id_pe_tlsfeature[] = {
+    0x2b, 0x06, 0x01, 0x05, 0x05, 0x07, 0x01, 0x18
+  };
+  // python DottedOIDToCode.py id-embeddedSctList 1.3.6.1.4.1.11129.2.4.2
+  // See Section 3.3 of RFC 6962.
+  static const uint8_t id_embeddedSctList[] = {
+    0x2b, 0x06, 0x01, 0x04, 0x01, 0xd6, 0x79, 0x02, 0x04, 0x02
+  };
+
+  Input* out = nullptr;
+
+  // We already enforce the maximum possible constraints for policies so we
+  // can safely ignore even critical policy constraint extensions.
+  //
+  // XXX: Doing it this way won't allow us to detect duplicate
+  // policyConstraints extensions, but that's OK because (and only because) we
+  // ignore the extension.
+  Input dummyPolicyConstraints;
+
+  // We don't need to save the contents of this extension if it is present. We
+  // just need to handle its presence (it is essentially ignored right now).
+  Input dummyOCSPNocheck;
+
+  // For compatibility reasons, for some extensions we have to allow empty
+  // extension values. This would normally interfere with our duplicate
+  // extension checking code. However, as long as the extensions we allow to
+  // have empty values are also the ones we implicitly allow duplicates of,
+  // this will work fine.
+  bool emptyValueAllowed = false;
+
+  // RFC says "Conforming CAs MUST mark this extension as non-critical" for
+  // both authorityKeyIdentifier and subjectKeyIdentifier, and we do not use
+  // them for anything, so we totally ignore them here.
+
+  if (extnID.MatchRest(id_ce_keyUsage)) {
+    out = &keyUsage;
+  } else if (extnID.MatchRest(id_ce_subjectAltName)) {
+    out = &subjectAltName;
+  } else if (extnID.MatchRest(id_ce_basicConstraints)) {
+    out = &basicConstraints;
+  } else if (extnID.MatchRest(id_ce_nameConstraints)) {
+    out = &nameConstraints;
+  } else if (extnID.MatchRest(id_ce_certificatePolicies)) {
+    out = &certificatePolicies;
+  } else if (extnID.MatchRest(id_ce_policyConstraints)) {
+    out = &dummyPolicyConstraints;
+  } else if (extnID.MatchRest(id_ce_extKeyUsage)) {
+    out = &extKeyUsage;
+  } else if (extnID.MatchRest(id_ce_inhibitAnyPolicy)) {
+    out = &inhibitAnyPolicy;
+  } else if (extnID.MatchRest(id_pe_authorityInfoAccess)) {
+    out = &authorityInfoAccess;
+  } else if (extnID.MatchRest(id_pe_tlsfeature)) {
+    out = &requiredTLSFeatures;
+  } else if (extnID.MatchRest(id_embeddedSctList)) {
+    out = &signedCertificateTimestamps;
+  } else if (extnID.MatchRest(id_pkix_ocsp_nocheck) && critical) {
+    // We need to make sure we don't reject delegated OCSP response signing
+    // certificates that contain the id-pkix-ocsp-nocheck extension marked as
+    // critical when validating OCSP responses. Without this, an application
+    // that implements soft-fail OCSP might ignore a valid Revoked or Unknown
+    // response, and an application that implements hard-fail OCSP might fail
+    // to connect to a server given a valid Good response.
+    out = &dummyOCSPNocheck;
+    // We allow this extension to have an empty value.
+    // See http://comments.gmane.org/gmane.ietf.x509/30947
+    emptyValueAllowed = true;
+  } else if (extnID.MatchRest(Netscape_certificate_type) && critical) {
+    out = &criticalNetscapeCertificateType;
+  }
+
+  if (out) {
+    // Don't allow an empty value for any extension we understand. This way, we
+    // can test out->GetLength() != 0 or out->Init() to check for duplicates.
+    if (extnValue.GetLength() == 0 && !emptyValueAllowed) {
+      return Result::ERROR_EXTENSION_VALUE_INVALID;
+    }
+    if (out->Init(extnValue) != Success) {
+      // Duplicate extension
+      return Result::ERROR_EXTENSION_VALUE_INVALID;
+    }
+    understood = true;
+  }
+
+  return Success;
+}
+
+Result
+ExtractSignedCertificateTimestampListFromExtension(Input extnValue,
+                                                   Input& sctList)
+{
+  Reader decodedValue;
+  Result rv = der::ExpectTagAndGetValueAtEnd(extnValue, der::OCTET_STRING,
+                                             decodedValue);
+  if (rv != Success) {
+    return rv;
+  }
+  return decodedValue.SkipToEnd(sctList);
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixcheck.cpp b/security/pkix/lib/pkixcheck.cpp
new file mode 100644
index 000000000..be2d2837a
--- /dev/null
+++ b/security/pkix/lib/pkixcheck.cpp
@@ -0,0 +1,1088 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkixcheck.h"
+
+#include "pkixder.h"
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix {
+
+// 4.1.1.2 signatureAlgorithm
+// 4.1.2.3 signature
+
+Result
+CheckSignatureAlgorithm(TrustDomain& trustDomain,
+                        EndEntityOrCA endEntityOrCA,
+                        Time notBefore,
+                        const der::SignedDataWithSignature& signedData,
+                        Input signatureValue)
+{
+  // 4.1.1.2. signatureAlgorithm
+  der::PublicKeyAlgorithm publicKeyAlg;
+  DigestAlgorithm digestAlg;
+  Reader signatureAlgorithmReader(signedData.algorithm);
+  Result rv = der::SignatureAlgorithmIdentifierValue(signatureAlgorithmReader,
+                                                     publicKeyAlg, digestAlg);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::End(signatureAlgorithmReader);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.1.2.3. Signature
+  der::PublicKeyAlgorithm signedPublicKeyAlg;
+  DigestAlgorithm signedDigestAlg;
+  Reader signedSignatureAlgorithmReader(signatureValue);
+  rv = der::SignatureAlgorithmIdentifierValue(signedSignatureAlgorithmReader,
+                                              signedPublicKeyAlg,
+                                              signedDigestAlg);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::End(signedSignatureAlgorithmReader);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // "This field MUST contain the same algorithm identifier as the
+  // signatureAlgorithm field in the sequence Certificate." However, it may
+  // be encoded differently. In particular, one of the fields may have a NULL
+  // parameter while the other one may omit the parameter field altogether, and
+  // these are considered equivalent. Some certificates generation software
+  // actually generates certificates like that, so we compare the parsed values
+  // instead of comparing the encoded values byte-for-byte.
+  //
+  // Along the same lines, we accept two different OIDs for RSA-with-SHA1, and
+  // we consider those OIDs to be equivalent here.
+  if (publicKeyAlg != signedPublicKeyAlg || digestAlg != signedDigestAlg) {
+    return Result::ERROR_SIGNATURE_ALGORITHM_MISMATCH;
+  }
+
+  // During the time of the deprecation of SHA-1 and the deprecation of RSA
+  // keys of less than 2048 bits, we will encounter many certs signed using
+  // SHA-1 and/or too-small RSA keys. With this in mind, we ask the trust
+  // domain early on if it knows it will reject the signature purely based on
+  // the digest algorithm and/or the RSA key size (if an RSA signature). This
+  // is a good optimization because it completely avoids calling
+  // trustDomain.FindIssuers (which may be slow) for such rejected certs, and
+  // more generally it short-circuits any path building with them (which, of
+  // course, is even slower).
+
+  rv = trustDomain.CheckSignatureDigestAlgorithm(digestAlg, endEntityOrCA,
+                                                 notBefore);
+  if (rv != Success) {
+    return rv;
+  }
+
+  switch (publicKeyAlg) {
+    case der::PublicKeyAlgorithm::RSA_PKCS1:
+    {
+      // The RSA computation may give a result that requires fewer bytes to
+      // encode than the public key (since it is modular arithmetic). However,
+      // the last step of generating a PKCS#1.5 signature is the I2OSP
+      // procedure, which pads any such shorter result with zeros so that it
+      // is exactly the same length as the public key.
+      unsigned int signatureSizeInBits = signedData.signature.GetLength() * 8u;
+      return trustDomain.CheckRSAPublicKeyModulusSizeInBits(
+               endEntityOrCA, signatureSizeInBits);
+    }
+
+    case der::PublicKeyAlgorithm::ECDSA:
+      // In theory, we could implement a similar early-pruning optimization for
+      // ECDSA curves. However, since there has been no similar deprecation for
+      // for any curve that we support, the chances of us encountering a curve
+      // during path building is too low to be worth bothering with.
+      break;
+
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+
+  return Success;
+}
+
+// 4.1.2.4 Issuer
+
+Result
+CheckIssuer(Input encodedIssuer)
+{
+  // "The issuer field MUST contain a non-empty distinguished name (DN)."
+  Reader issuer(encodedIssuer);
+  Input encodedRDNs;
+  ExpectTagAndGetValue(issuer, der::SEQUENCE, encodedRDNs);
+  Reader rdns(encodedRDNs);
+  // Check that the issuer name contains at least one RDN
+  // (Note: this does not check related grammar rules, such as there being one
+  // or more AVAs in each RDN, or the values in AVAs not being empty strings)
+  if (rdns.AtEnd()) {
+    return Result::ERROR_EMPTY_ISSUER_NAME;
+  }
+  return Success;
+}
+
+// 4.1.2.5 Validity
+
+Result
+ParseValidity(Input encodedValidity,
+              /*optional out*/ Time* notBeforeOut,
+              /*optional out*/ Time* notAfterOut)
+{
+  Reader validity(encodedValidity);
+  Time notBefore(Time::uninitialized);
+  if (der::TimeChoice(validity, notBefore) != Success) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+
+  Time notAfter(Time::uninitialized);
+  if (der::TimeChoice(validity, notAfter) != Success) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+
+  if (der::End(validity) != Success) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+
+  if (notBefore > notAfter) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+
+  if (notBeforeOut) {
+    *notBeforeOut = notBefore;
+  }
+  if (notAfterOut) {
+    *notAfterOut = notAfter;
+  }
+
+  return Success;
+}
+
+Result
+CheckValidity(Time time, Time notBefore, Time notAfter)
+{
+  if (time < notBefore) {
+    return Result::ERROR_NOT_YET_VALID_CERTIFICATE;
+  }
+
+  if (time > notAfter) {
+    return Result::ERROR_EXPIRED_CERTIFICATE;
+  }
+
+  return Success;
+}
+
+// 4.1.2.7 Subject Public Key Info
+
+Result
+CheckSubjectPublicKeyInfoContents(Reader& input, TrustDomain& trustDomain,
+                                  EndEntityOrCA endEntityOrCA)
+{
+  // Here, we validate the syntax and do very basic semantic validation of the
+  // public key of the certificate. The intention here is to filter out the
+  // types of bad inputs that are most likely to trigger non-mathematical
+  // security vulnerabilities in the TrustDomain, like buffer overflows or the
+  // use of unsafe elliptic curves.
+  //
+  // We don't check (all of) the mathematical properties of the public key here
+  // because it is more efficient for the TrustDomain to do it during signature
+  // verification and/or other use of the public key. In particular, we
+  // delegate the arithmetic validation of the public key, as specified in
+  // NIST SP800-56A section 5.6.2, to the TrustDomain, at least for now.
+
+  Reader algorithm;
+  Input subjectPublicKey;
+  Result rv = der::ExpectTagAndGetValue(input, der::SEQUENCE, algorithm);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::BitStringWithNoUnusedBits(input, subjectPublicKey);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::End(input);
+  if (rv != Success) {
+    return rv;
+  }
+
+  Reader subjectPublicKeyReader(subjectPublicKey);
+
+  Reader algorithmOID;
+  rv = der::ExpectTagAndGetValue(algorithm, der::OIDTag, algorithmOID);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // RFC 3279 Section 2.3.1
+  // python DottedOIDToCode.py rsaEncryption 1.2.840.113549.1.1.1
+  static const uint8_t rsaEncryption[] = {
+    0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01
+  };
+
+  // RFC 3279 Section 2.3.5 and RFC 5480 Section 2.1.1
+  // python DottedOIDToCode.py id-ecPublicKey 1.2.840.10045.2.1
+  static const uint8_t id_ecPublicKey[] = {
+    0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01
+  };
+
+  if (algorithmOID.MatchRest(id_ecPublicKey)) {
+    // An id-ecPublicKey AlgorithmIdentifier has a parameter that identifes
+    // the curve being used. Although RFC 5480 specifies multiple forms, we
+    // only supported the NamedCurve form, where the curve is identified by an
+    // OID.
+
+    Reader namedCurveOIDValue;
+    rv = der::ExpectTagAndGetValue(algorithm, der::OIDTag,
+                                   namedCurveOIDValue);
+    if (rv != Success) {
+      return rv;
+    }
+
+    // RFC 5480
+    // python DottedOIDToCode.py secp256r1 1.2.840.10045.3.1.7
+    static const uint8_t secp256r1[] = {
+      0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07
+    };
+
+    // RFC 5480
+    // python DottedOIDToCode.py secp384r1 1.3.132.0.34
+    static const uint8_t secp384r1[] = {
+      0x2b, 0x81, 0x04, 0x00, 0x22
+    };
+
+    // RFC 5480
+    // python DottedOIDToCode.py secp521r1 1.3.132.0.35
+    static const uint8_t secp521r1[] = {
+      0x2b, 0x81, 0x04, 0x00, 0x23
+    };
+
+    // Matching is attempted based on a rough estimate of the commonality of the
+    // elliptic curve, to minimize the number of MatchRest calls.
+    NamedCurve curve;
+    unsigned int bits;
+    if (namedCurveOIDValue.MatchRest(secp256r1)) {
+      curve = NamedCurve::secp256r1;
+      bits = 256;
+    } else if (namedCurveOIDValue.MatchRest(secp384r1)) {
+      curve = NamedCurve::secp384r1;
+      bits = 384;
+    } else if (namedCurveOIDValue.MatchRest(secp521r1)) {
+      curve = NamedCurve::secp521r1;
+      bits = 521;
+    } else {
+      return Result::ERROR_UNSUPPORTED_ELLIPTIC_CURVE;
+    }
+
+    rv = trustDomain.CheckECDSACurveIsAcceptable(endEntityOrCA, curve);
+    if (rv != Success) {
+      return rv;
+    }
+
+    // RFC 5480 Section 2.2 says that the first octet will be 0x04 to indicate
+    // an uncompressed point, which is the only encoding we support.
+    uint8_t compressedOrUncompressed;
+    rv = subjectPublicKeyReader.Read(compressedOrUncompressed);
+    if (rv != Success) {
+      return rv;
+    }
+    if (compressedOrUncompressed != 0x04) {
+      return Result::ERROR_UNSUPPORTED_EC_POINT_FORM;
+    }
+
+    // The point is encoded as two raw (not DER-encoded) integers, each padded
+    // to the bit length (rounded up to the nearest byte).
+    Input point;
+    rv = subjectPublicKeyReader.SkipToEnd(point);
+    if (rv != Success) {
+      return rv;
+    }
+    if (point.GetLength() != ((bits + 7) / 8u) * 2u) {
+      return Result::ERROR_BAD_DER;
+    }
+
+    // XXX: We defer the mathematical verification of the validity of the point
+    // until signature verification. This means that if we never verify a
+    // signature, we'll never fully check whether the public key is valid.
+  } else if (algorithmOID.MatchRest(rsaEncryption)) {
+    // RFC 3279 Section 2.3.1 says "The parameters field MUST have ASN.1 type
+    // NULL for this algorithm identifier."
+    rv = der::ExpectTagAndEmptyValue(algorithm, der::NULLTag);
+    if (rv != Success) {
+      return rv;
+    }
+
+    // RSAPublicKey :: = SEQUENCE{
+    //    modulus            INTEGER,    --n
+    //    publicExponent     INTEGER  }  --e
+    rv = der::Nested(subjectPublicKeyReader, der::SEQUENCE,
+                     [&trustDomain, endEntityOrCA](Reader& r) {
+      Input modulus;
+      Input::size_type modulusSignificantBytes;
+      Result rv = der::PositiveInteger(r, modulus, &modulusSignificantBytes);
+      if (rv != Success) {
+        return rv;
+      }
+      // XXX: Should we do additional checks of the modulus?
+      rv = trustDomain.CheckRSAPublicKeyModulusSizeInBits(
+             endEntityOrCA, modulusSignificantBytes * 8u);
+      if (rv != Success) {
+        return rv;
+      }
+
+      // XXX: We don't allow the TrustDomain to validate the exponent.
+      // XXX: We don't do our own sanity checking of the exponent.
+      Input exponent;
+      return der::PositiveInteger(r, exponent);
+    });
+    if (rv != Success) {
+      return rv;
+    }
+  } else {
+    return Result::ERROR_UNSUPPORTED_KEYALG;
+  }
+
+  rv = der::End(algorithm);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::End(subjectPublicKeyReader);
+  if (rv != Success) {
+    return rv;
+  }
+
+  return Success;
+}
+
+Result
+CheckSubjectPublicKeyInfo(Input subjectPublicKeyInfo, TrustDomain& trustDomain,
+                          EndEntityOrCA endEntityOrCA)
+{
+  Reader spkiReader(subjectPublicKeyInfo);
+  Result rv = der::Nested(spkiReader, der::SEQUENCE, [&](Reader& r) {
+    return CheckSubjectPublicKeyInfoContents(r, trustDomain, endEntityOrCA);
+  });
+  if (rv != Success) {
+    return rv;
+  }
+  return der::End(spkiReader);
+}
+
+// 4.2.1.3. Key Usage (id-ce-keyUsage)
+
+// As explained in the comment in CheckKeyUsage, bit 0 is the most significant
+// bit and bit 7 is the least significant bit.
+inline uint8_t KeyUsageToBitMask(KeyUsage keyUsage)
+{
+  assert(keyUsage != KeyUsage::noParticularKeyUsageRequired);
+  return 0x80u >> static_cast<uint8_t>(keyUsage);
+}
+
+Result
+CheckKeyUsage(EndEntityOrCA endEntityOrCA, const Input* encodedKeyUsage,
+              KeyUsage requiredKeyUsageIfPresent)
+{
+  if (!encodedKeyUsage) {
+    // TODO(bug 970196): Reject certificates that are being used to verify
+    // certificate signatures unless the certificate is a trust anchor, to
+    // reduce the chances of an end-entity certificate being abused as a CA
+    // certificate.
+    // if (endEntityOrCA == EndEntityOrCA::MustBeCA && !isTrustAnchor) {
+    //   return Result::ERROR_INADEQUATE_KEY_USAGE;
+    // }
+    //
+    // TODO: Users may configure arbitrary certificates as trust anchors, not
+    // just roots. We should only allow a certificate without a key usage to be
+    // used as a CA when it is self-issued and self-signed.
+    return Success;
+  }
+
+  Reader input(*encodedKeyUsage);
+  Reader value;
+  if (der::ExpectTagAndGetValue(input, der::BIT_STRING, value) != Success) {
+    return Result::ERROR_INADEQUATE_KEY_USAGE;
+  }
+
+  uint8_t numberOfPaddingBits;
+  if (value.Read(numberOfPaddingBits) != Success) {
+    return Result::ERROR_INADEQUATE_KEY_USAGE;
+  }
+  if (numberOfPaddingBits > 7) {
+    return Result::ERROR_INADEQUATE_KEY_USAGE;
+  }
+
+  uint8_t bits;
+  if (value.Read(bits) != Success) {
+    // Reject empty bit masks.
+    return Result::ERROR_INADEQUATE_KEY_USAGE;
+  }
+
+  // The most significant bit is numbered 0 (digitalSignature) and the least
+  // significant bit is numbered 7 (encipherOnly), and the padding is in the
+  // least significant bits of the last byte. The numbering of bits in a byte
+  // is backwards from how we usually interpret them.
+  //
+  // For example, let's say bits is encoded in one byte with of value 0xB0 and
+  // numberOfPaddingBits == 4. Then, bits is 10110000 in binary:
+  //
+  //      bit 0  bit 3
+  //          |  |
+  //          v  v
+  //          10110000
+  //              ^^^^
+  //               |
+  //               4 padding bits
+  //
+  // Since bits is the last byte, we have to consider the padding by ensuring
+  // that the least significant 4 bits are all zero, since DER rules require
+  // all padding bits to be zero. Then we have to look at the bit N bits to the
+  // right of the most significant bit, where N is a value from the KeyUsage
+  // enumeration.
+  //
+  // Let's say we're interested in the keyCertSign (5) bit. We'd need to look
+  // at bit 5, which is zero, so keyCertSign is not asserted. (Since we check
+  // that the padding is all zeros, it is OK to read from the padding bits.)
+  //
+  // Let's say we're interested in the digitalSignature (0) bit. We'd need to
+  // look at the bit 0 (the most significant bit), which is set, so that means
+  // digitalSignature is asserted. Similarly, keyEncipherment (2) and
+  // dataEncipherment (3) are asserted.
+  //
+  // Note that since the KeyUsage enumeration is limited to values 0-7, we
+  // only ever need to examine the first byte test for
+  // requiredKeyUsageIfPresent.
+
+  if (requiredKeyUsageIfPresent != KeyUsage::noParticularKeyUsageRequired) {
+    // Check that the required key usage bit is set.
+    if ((bits & KeyUsageToBitMask(requiredKeyUsageIfPresent)) == 0) {
+      return Result::ERROR_INADEQUATE_KEY_USAGE;
+    }
+  }
+
+  // RFC 5280 says "The keyCertSign bit is asserted when the subject public
+  // key is used for verifying signatures on public key certificates. If the
+  // keyCertSign bit is asserted, then the cA bit in the basic constraints
+  // extension (Section 4.2.1.9) MUST also be asserted."
+  // However, we allow end-entity certificates (i.e. certificates without
+  // basicConstraints.cA set to TRUE) to claim keyCertSign for compatibility
+  // reasons. This does not compromise security because we only allow
+  // certificates with basicConstraints.cA set to TRUE to act as CAs.
+  if (requiredKeyUsageIfPresent == KeyUsage::keyCertSign &&
+      endEntityOrCA != EndEntityOrCA::MustBeCA) {
+    return Result::ERROR_INADEQUATE_KEY_USAGE;
+  }
+
+  // The padding applies to the last byte, so skip to the last byte.
+  while (!value.AtEnd()) {
+    if (value.Read(bits) != Success) {
+      return Result::ERROR_INADEQUATE_KEY_USAGE;
+    }
+  }
+
+  // All of the padding bits must be zero, according to DER rules.
+  uint8_t paddingMask = static_cast<uint8_t>((1 << numberOfPaddingBits) - 1);
+  if ((bits & paddingMask) != 0) {
+    return Result::ERROR_INADEQUATE_KEY_USAGE;
+  }
+
+  return Success;
+}
+
+// RFC5820 4.2.1.4. Certificate Policies
+
+// "The user-initial-policy-set contains the special value any-policy if the
+// user is not concerned about certificate policy."
+//
+// python DottedOIDToCode.py anyPolicy 2.5.29.32.0
+
+static const uint8_t anyPolicy[] = {
+  0x55, 0x1d, 0x20, 0x00
+};
+
+/*static*/ const CertPolicyId CertPolicyId::anyPolicy = {
+  4, { 0x55, 0x1d, 0x20, 0x00 }
+};
+
+bool
+CertPolicyId::IsAnyPolicy() const {
+  if (this == &CertPolicyId::anyPolicy) {
+    return true;
+  }
+  return numBytes == sizeof(::mozilla::pkix::anyPolicy) &&
+         std::equal(bytes, bytes + numBytes, ::mozilla::pkix::anyPolicy);
+}
+
+// certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation
+Result
+CheckCertificatePolicies(EndEntityOrCA endEntityOrCA,
+                         const Input* encodedCertificatePolicies,
+                         const Input* encodedInhibitAnyPolicy,
+                         TrustLevel trustLevel,
+                         const CertPolicyId& requiredPolicy)
+{
+  if (requiredPolicy.numBytes == 0 ||
+      requiredPolicy.numBytes > sizeof requiredPolicy.bytes) {
+    return Result::FATAL_ERROR_INVALID_ARGS;
+  }
+
+  bool requiredPolicyFound = requiredPolicy.IsAnyPolicy();
+  if (requiredPolicyFound) {
+    return Success;
+  }
+
+  // Bug 989051. Until we handle inhibitAnyPolicy we will fail close when
+  // inhibitAnyPolicy extension is present and we are validating for a policy.
+  if (!requiredPolicyFound && encodedInhibitAnyPolicy) {
+    return Result::ERROR_POLICY_VALIDATION_FAILED;
+  }
+
+  // The root CA certificate may omit the policies that it has been
+  // trusted for, so we cannot require the policies to be present in those
+  // certificates. Instead, the determination of which roots are trusted for
+  // which policies is made by the TrustDomain's GetCertTrust method.
+  if (trustLevel == TrustLevel::TrustAnchor &&
+      endEntityOrCA == EndEntityOrCA::MustBeCA) {
+    requiredPolicyFound = true;
+  }
+
+  Input requiredPolicyDER;
+  if (requiredPolicyDER.Init(requiredPolicy.bytes, requiredPolicy.numBytes)
+        != Success) {
+    return Result::FATAL_ERROR_INVALID_ARGS;
+  }
+
+  if (encodedCertificatePolicies) {
+    Reader extension(*encodedCertificatePolicies);
+    Reader certificatePolicies;
+    Result rv = der::ExpectTagAndGetValue(extension, der::SEQUENCE,
+                                          certificatePolicies);
+    if (rv != Success) {
+      return Result::ERROR_POLICY_VALIDATION_FAILED;
+    }
+    if (!extension.AtEnd()) {
+      return Result::ERROR_POLICY_VALIDATION_FAILED;
+    }
+
+    do {
+      // PolicyInformation ::= SEQUENCE {
+      //         policyIdentifier   CertPolicyId,
+      //         policyQualifiers   SEQUENCE SIZE (1..MAX) OF
+      //                                 PolicyQualifierInfo OPTIONAL }
+      Reader policyInformation;
+      rv = der::ExpectTagAndGetValue(certificatePolicies, der::SEQUENCE,
+                                     policyInformation);
+      if (rv != Success) {
+        return Result::ERROR_POLICY_VALIDATION_FAILED;
+      }
+
+      Reader policyIdentifier;
+      rv = der::ExpectTagAndGetValue(policyInformation, der::OIDTag,
+                                     policyIdentifier);
+      if (rv != Success) {
+        return rv;
+      }
+
+      if (policyIdentifier.MatchRest(requiredPolicyDER)) {
+        requiredPolicyFound = true;
+      } else if (endEntityOrCA == EndEntityOrCA::MustBeCA &&
+                 policyIdentifier.MatchRest(anyPolicy)) {
+        requiredPolicyFound = true;
+      }
+
+      // RFC 5280 Section 4.2.1.4 says "Optional qualifiers, which MAY be
+      // present, are not expected to change the definition of the policy." Also,
+      // it seems that Section 6, which defines validation, does not require any
+      // matching of qualifiers. Thus, doing anything with the policy qualifiers
+      // would be a waste of time and a source of potential incompatibilities, so
+      // we just ignore them.
+    } while (!requiredPolicyFound && !certificatePolicies.AtEnd());
+  }
+
+  if (!requiredPolicyFound) {
+    return Result::ERROR_POLICY_VALIDATION_FAILED;
+  }
+
+  return Success;
+}
+
+static const long UNLIMITED_PATH_LEN = -1; // must be less than zero
+
+//  BasicConstraints ::= SEQUENCE {
+//          cA                      BOOLEAN DEFAULT FALSE,
+//          pathLenConstraint       INTEGER (0..MAX) OPTIONAL }
+
+// RFC5280 4.2.1.9. Basic Constraints (id-ce-basicConstraints)
+Result
+CheckBasicConstraints(EndEntityOrCA endEntityOrCA,
+                      const Input* encodedBasicConstraints,
+                      const der::Version version, TrustLevel trustLevel,
+                      unsigned int subCACount)
+{
+  bool isCA = false;
+  long pathLenConstraint = UNLIMITED_PATH_LEN;
+
+  if (encodedBasicConstraints) {
+    Reader input(*encodedBasicConstraints);
+    Result rv = der::Nested(input, der::SEQUENCE,
+                            [&isCA, &pathLenConstraint](Reader& r) {
+      Result rv = der::OptionalBoolean(r, isCA);
+      if (rv != Success) {
+        return rv;
+      }
+      // TODO(bug 985025): If isCA is false, pathLenConstraint
+      // MUST NOT be included (as per RFC 5280 section
+      // 4.2.1.9), but for compatibility reasons, we don't
+      // check this.
+      return der::OptionalInteger(r, UNLIMITED_PATH_LEN, pathLenConstraint);
+    });
+    if (rv != Success) {
+      return Result::ERROR_EXTENSION_VALUE_INVALID;
+    }
+    if (der::End(input) != Success) {
+      return Result::ERROR_EXTENSION_VALUE_INVALID;
+    }
+  } else {
+    // "If the basic constraints extension is not present in a version 3
+    //  certificate, or the extension is present but the cA boolean is not
+    //  asserted, then the certified public key MUST NOT be used to verify
+    //  certificate signatures."
+    //
+    // For compatibility, we must accept v1 trust anchors without basic
+    // constraints as CAs.
+    //
+    // There are devices with v1 certificates that are unlikely to be trust
+    // anchors. In order to allow applications to treat this case differently
+    // from other basic constraints violations (e.g. allowing certificate error
+    // overrides for only this case), we return a different error code.
+    //
+    // TODO: add check for self-signedness?
+    if (endEntityOrCA == EndEntityOrCA::MustBeCA && version == der::Version::v1) {
+      if (trustLevel == TrustLevel::TrustAnchor) {
+        isCA = true;
+      } else {
+        return Result::ERROR_V1_CERT_USED_AS_CA;
+      }
+    }
+  }
+
+  if (endEntityOrCA == EndEntityOrCA::MustBeEndEntity) {
+    // CA certificates are not trusted as EE certs.
+
+    if (isCA) {
+      // Note that this check prevents a delegated OCSP response signing
+      // certificate with the CA bit from successfully validating when we check
+      // it from pkixocsp.cpp, which is a good thing.
+      return Result::ERROR_CA_CERT_USED_AS_END_ENTITY;
+    }
+
+    return Success;
+  }
+
+  assert(endEntityOrCA == EndEntityOrCA::MustBeCA);
+
+  // End-entity certificates are not allowed to act as CA certs.
+  if (!isCA) {
+    return Result::ERROR_CA_CERT_INVALID;
+  }
+
+  if (pathLenConstraint >= 0 &&
+      static_cast<long>(subCACount) > pathLenConstraint) {
+    return Result::ERROR_PATH_LEN_CONSTRAINT_INVALID;
+  }
+
+  return Success;
+}
+
+// 4.2.1.12. Extended Key Usage (id-ce-extKeyUsage)
+
+static Result
+MatchEKU(Reader& value, KeyPurposeId requiredEKU,
+         EndEntityOrCA endEntityOrCA, TrustDomain& trustDomain,
+         Time notBefore, /*in/out*/ bool& found,
+         /*in/out*/ bool& foundOCSPSigning)
+{
+  // See Section 5.9 of "A Layman's Guide to a Subset of ASN.1, BER, and DER"
+  // for a description of ASN.1 DER encoding of OIDs.
+
+  // id-pkix  OBJECT IDENTIFIER  ::=
+  //            { iso(1) identified-organization(3) dod(6) internet(1)
+  //                    security(5) mechanisms(5) pkix(7) }
+  // id-kp OBJECT IDENTIFIER ::= { id-pkix 3 }
+  // id-kp-serverAuth      OBJECT IDENTIFIER ::= { id-kp 1 }
+  // id-kp-clientAuth      OBJECT IDENTIFIER ::= { id-kp 2 }
+  // id-kp-codeSigning     OBJECT IDENTIFIER ::= { id-kp 3 }
+  // id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 }
+  // id-kp-OCSPSigning     OBJECT IDENTIFIER ::= { id-kp 9 }
+  static const uint8_t server[] = { (40*1)+3, 6, 1, 5, 5, 7, 3, 1 };
+  static const uint8_t client[] = { (40*1)+3, 6, 1, 5, 5, 7, 3, 2 };
+  static const uint8_t code  [] = { (40*1)+3, 6, 1, 5, 5, 7, 3, 3 };
+  static const uint8_t email [] = { (40*1)+3, 6, 1, 5, 5, 7, 3, 4 };
+  static const uint8_t ocsp  [] = { (40*1)+3, 6, 1, 5, 5, 7, 3, 9 };
+
+  // id-Netscape        OBJECT IDENTIFIER ::= { 2 16 840 1 113730 }
+  // id-Netscape-policy OBJECT IDENTIFIER ::= { id-Netscape 4 }
+  // id-Netscape-stepUp OBJECT IDENTIFIER ::= { id-Netscape-policy 1 }
+  static const uint8_t serverStepUp[] =
+    { (40*2)+16, 128+6,72, 1, 128+6,128+120,66, 4, 1 };
+
+  bool match = false;
+
+  if (!found) {
+    switch (requiredEKU) {
+      case KeyPurposeId::id_kp_serverAuth: {
+        if (value.MatchRest(server)) {
+          match = true;
+          break;
+        }
+        // Potentially treat CA certs with step-up OID as also having SSL server
+        // type. Comodo has issued certificates that require this behavior that
+        // don't expire until June 2020!
+        if (endEntityOrCA == EndEntityOrCA::MustBeCA &&
+            value.MatchRest(serverStepUp)) {
+          Result rv = trustDomain.NetscapeStepUpMatchesServerAuth(notBefore,
+                                                                  match);
+          if (rv != Success) {
+            return rv;
+          }
+        }
+        break;
+      }
+
+      case KeyPurposeId::id_kp_clientAuth:
+        match = value.MatchRest(client);
+        break;
+
+      case KeyPurposeId::id_kp_codeSigning:
+        match = value.MatchRest(code);
+        break;
+
+      case KeyPurposeId::id_kp_emailProtection:
+        match = value.MatchRest(email);
+        break;
+
+      case KeyPurposeId::id_kp_OCSPSigning:
+        match = value.MatchRest(ocsp);
+        break;
+
+      case KeyPurposeId::anyExtendedKeyUsage:
+        return NotReached("anyExtendedKeyUsage should start with found==true",
+                          Result::FATAL_ERROR_LIBRARY_FAILURE);
+    }
+  }
+
+  if (match) {
+    found = true;
+    if (requiredEKU == KeyPurposeId::id_kp_OCSPSigning) {
+      foundOCSPSigning = true;
+    }
+  } else if (value.MatchRest(ocsp)) {
+    foundOCSPSigning = true;
+  }
+
+  value.SkipToEnd(); // ignore unmatched OIDs.
+
+  return Success;
+}
+
+Result
+CheckExtendedKeyUsage(EndEntityOrCA endEntityOrCA,
+                      const Input* encodedExtendedKeyUsage,
+                      KeyPurposeId requiredEKU, TrustDomain& trustDomain,
+                      Time notBefore)
+{
+  // XXX: We're using Result::ERROR_INADEQUATE_CERT_TYPE here so that callers
+  // can distinguish EKU mismatch from KU mismatch from basic constraints
+  // mismatch. We should probably add a new error code that is more clear for
+  // this type of problem.
+
+  bool foundOCSPSigning = false;
+
+  if (encodedExtendedKeyUsage) {
+    bool found = requiredEKU == KeyPurposeId::anyExtendedKeyUsage;
+
+    Reader input(*encodedExtendedKeyUsage);
+    Result rv = der::NestedOf(input, der::SEQUENCE, der::OIDTag,
+                              der::EmptyAllowed::No, [&](Reader& r) {
+      return MatchEKU(r, requiredEKU, endEntityOrCA, trustDomain, notBefore,
+                      found, foundOCSPSigning);
+    });
+    if (rv != Success) {
+      return Result::ERROR_INADEQUATE_CERT_TYPE;
+    }
+    if (der::End(input) != Success) {
+      return Result::ERROR_INADEQUATE_CERT_TYPE;
+    }
+
+    // If the EKU extension was included, then the required EKU must be in the
+    // list.
+    if (!found) {
+      return Result::ERROR_INADEQUATE_CERT_TYPE;
+    }
+  }
+
+  // pkixocsp.cpp depends on the following additional checks.
+
+  if (endEntityOrCA == EndEntityOrCA::MustBeEndEntity) {
+    // When validating anything other than an delegated OCSP signing cert,
+    // reject any cert that also claims to be an OCSP responder, because such
+    // a cert does not make sense. For example, if an SSL certificate were to
+    // assert id-kp-OCSPSigning then it could sign OCSP responses for itself,
+    // if not for this check.
+    // That said, we accept CA certificates with id-kp-OCSPSigning because
+    // some CAs in Mozilla's CA program have issued such intermediate
+    // certificates, and because some CAs have reported some Microsoft server
+    // software wrongly requires CA certificates to have id-kp-OCSPSigning.
+    // Allowing this exception does not cause any security issues because we
+    // require delegated OCSP response signing certificates to be end-entity
+    // certificates.
+    if (foundOCSPSigning && requiredEKU != KeyPurposeId::id_kp_OCSPSigning) {
+      return Result::ERROR_INADEQUATE_CERT_TYPE;
+    }
+    // http://tools.ietf.org/html/rfc6960#section-4.2.2.2:
+    // "OCSP signing delegation SHALL be designated by the inclusion of
+    // id-kp-OCSPSigning in an extended key usage certificate extension
+    // included in the OCSP response signer's certificate."
+    //
+    // id-kp-OCSPSigning is the only EKU that isn't implicitly assumed when the
+    // EKU extension is missing from an end-entity certificate. However, any CA
+    // certificate can issue a delegated OCSP response signing certificate, so
+    // we can't require the EKU be explicitly included for CA certificates.
+    if (!foundOCSPSigning && requiredEKU == KeyPurposeId::id_kp_OCSPSigning) {
+      return Result::ERROR_INADEQUATE_CERT_TYPE;
+    }
+  }
+
+  return Success;
+}
+
+Result
+CheckTLSFeatures(const BackCert& subject, BackCert& potentialIssuer)
+{
+  const Input* issuerTLSFeatures = potentialIssuer.GetRequiredTLSFeatures();
+  if (!issuerTLSFeatures) {
+    return Success;
+  }
+
+  const Input* subjectTLSFeatures = subject.GetRequiredTLSFeatures();
+  if (issuerTLSFeatures->GetLength() == 0 ||
+      !subjectTLSFeatures ||
+      !InputsAreEqual(*issuerTLSFeatures, *subjectTLSFeatures)) {
+    return Result::ERROR_REQUIRED_TLS_FEATURE_MISSING;
+  }
+
+  return Success;
+}
+
+Result
+TLSFeaturesSatisfiedInternal(const Input* requiredTLSFeatures,
+                             const Input* stapledOCSPResponse)
+{
+  if (!requiredTLSFeatures) {
+    return Success;
+  }
+
+  // RFC 6066 10.2: ExtensionType status_request
+  const static uint8_t status_request = 5;
+  const static uint8_t status_request_bytes[] = { status_request };
+
+  Reader input(*requiredTLSFeatures);
+  return der::NestedOf(input, der::SEQUENCE, der::INTEGER,
+                       der::EmptyAllowed::No, [&](Reader& r) {
+    if (!r.MatchRest(status_request_bytes)) {
+      return Result::ERROR_REQUIRED_TLS_FEATURE_MISSING;
+    }
+
+    if (!stapledOCSPResponse) {
+      return Result::ERROR_REQUIRED_TLS_FEATURE_MISSING;
+    }
+
+    return Result::Success;
+  });
+}
+
+Result
+CheckTLSFeaturesAreSatisfied(Input& cert,
+                             const Input* stapledOCSPResponse)
+{
+  BackCert backCert(cert, EndEntityOrCA::MustBeEndEntity, nullptr);
+  Result rv = backCert.Init();
+  if (rv != Success) {
+    return rv;
+  }
+
+  return TLSFeaturesSatisfiedInternal(backCert.GetRequiredTLSFeatures(),
+                                      stapledOCSPResponse);
+}
+
+Result
+CheckIssuerIndependentProperties(TrustDomain& trustDomain,
+                                 const BackCert& cert,
+                                 Time time,
+                                 KeyUsage requiredKeyUsageIfPresent,
+                                 KeyPurposeId requiredEKUIfPresent,
+                                 const CertPolicyId& requiredPolicy,
+                                 unsigned int subCACount,
+                                 /*out*/ TrustLevel& trustLevel)
+{
+  Result rv;
+
+  const EndEntityOrCA endEntityOrCA = cert.endEntityOrCA;
+
+  // Check the cert's trust first, because we want to minimize the amount of
+  // processing we do on a distrusted cert, in case it is trying to exploit
+  // some bug in our processing.
+  rv = trustDomain.GetCertTrust(endEntityOrCA, requiredPolicy, cert.GetDER(),
+                                trustLevel);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // IMPORTANT: We parse the validity interval here, so that we can use the
+  // notBefore and notAfter values in checks for things that might be deprecated
+  // over time. However, we must not fail for semantic errors until the end of
+  // this method, in order to preserve error ranking.
+  Time notBefore(Time::uninitialized);
+  Time notAfter(Time::uninitialized);
+  rv = ParseValidity(cert.GetValidity(), &notBefore, &notAfter);
+  if (rv != Success) {
+    return rv;
+  }
+
+  if (trustLevel == TrustLevel::TrustAnchor &&
+      endEntityOrCA == EndEntityOrCA::MustBeEndEntity &&
+      requiredEKUIfPresent == KeyPurposeId::id_kp_OCSPSigning) {
+    // OCSP signer certificates can never be trust anchors, especially
+    // since we don't support designated OCSP responders. All of the checks
+    // below that are dependent on trustLevel rely on this overriding of the
+    // trust level for OCSP signers.
+    trustLevel = TrustLevel::InheritsTrust;
+  }
+
+  switch (trustLevel) {
+    case TrustLevel::InheritsTrust:
+      rv = CheckSignatureAlgorithm(trustDomain, endEntityOrCA, notBefore,
+                                   cert.GetSignedData(), cert.GetSignature());
+      if (rv != Success) {
+        return rv;
+      }
+      break;
+
+    case TrustLevel::TrustAnchor:
+      // We don't even bother checking signatureAlgorithm or signature for
+      // syntactic validity for trust anchors, because we don't use those
+      // fields for anything, and because the trust anchor might be signed
+      // with a signature algorithm we don't actually support.
+      break;
+
+    case TrustLevel::ActivelyDistrusted:
+      return Result::ERROR_UNTRUSTED_CERT;
+  }
+
+  // Check the SPKI early, because it is one of the most selective properties
+  // of the certificate due to SHA-1 deprecation and the deprecation of
+  // certificates with keys weaker than RSA 2048.
+  rv = CheckSubjectPublicKeyInfo(cert.GetSubjectPublicKeyInfo(), trustDomain,
+                                 endEntityOrCA);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.1.2.4. Issuer
+  rv = CheckIssuer(cert.GetIssuer());
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.2.1.1. Authority Key Identifier is ignored (see bug 965136).
+
+  // 4.2.1.2. Subject Key Identifier is ignored (see bug 965136).
+
+  // 4.2.1.3. Key Usage
+  rv = CheckKeyUsage(endEntityOrCA, cert.GetKeyUsage(),
+                     requiredKeyUsageIfPresent);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.2.1.4. Certificate Policies
+  rv = CheckCertificatePolicies(endEntityOrCA, cert.GetCertificatePolicies(),
+                                cert.GetInhibitAnyPolicy(), trustLevel,
+                                requiredPolicy);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.2.1.5. Policy Mappings are not supported; see the documentation about
+  //          policy enforcement in pkix.h.
+
+  // 4.2.1.6. Subject Alternative Name dealt with during name constraint
+  //          checking and during name verification (CERT_VerifyCertName).
+
+  // 4.2.1.7. Issuer Alternative Name is not something that needs checking.
+
+  // 4.2.1.8. Subject Directory Attributes is not something that needs
+  //          checking.
+
+  // 4.2.1.9. Basic Constraints.
+  rv = CheckBasicConstraints(endEntityOrCA, cert.GetBasicConstraints(),
+                             cert.GetVersion(), trustLevel, subCACount);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.2.1.10. Name Constraints is dealt with in during path building.
+
+  // 4.2.1.11. Policy Constraints are implicitly supported; see the
+  //           documentation about policy enforcement in pkix.h.
+
+  // 4.2.1.12. Extended Key Usage
+  rv = CheckExtendedKeyUsage(endEntityOrCA, cert.GetExtKeyUsage(),
+                             requiredEKUIfPresent, trustDomain, notBefore);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // 4.2.1.13. CRL Distribution Points is not supported, though the
+  //           TrustDomain's CheckRevocation method may parse it and process it
+  //           on its own.
+
+  // 4.2.1.14. Inhibit anyPolicy is implicitly supported; see the documentation
+  //           about policy enforcement in pkix.h.
+
+  // IMPORTANT: Even though we parse validity above, we wait until this point to
+  // check it, so that error ranking works correctly.
+  rv = CheckValidity(time, notBefore, notAfter);
+  if (rv != Success) {
+    return rv;
+  }
+
+  rv = trustDomain.CheckValidityIsAcceptable(notBefore, notAfter, endEntityOrCA,
+                                             requiredEKUIfPresent);
+  if (rv != Success) {
+    return rv;
+  }
+
+  return Success;
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixcheck.h b/security/pkix/lib/pkixcheck.h
new file mode 100644
index 000000000..9ea205f3b
--- /dev/null
+++ b/security/pkix/lib/pkixcheck.h
@@ -0,0 +1,66 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef mozilla_pkix_pkixcheck_h
+#define mozilla_pkix_pkixcheck_h
+
+#include "pkix/pkixtypes.h"
+
+namespace mozilla { namespace pkix {
+
+class BackCert;
+
+Result CheckIssuerIndependentProperties(
+          TrustDomain& trustDomain,
+          const BackCert& cert,
+          Time time,
+          KeyUsage requiredKeyUsageIfPresent,
+          KeyPurposeId requiredEKUIfPresent,
+          const CertPolicyId& requiredPolicy,
+          unsigned int subCACount,
+          /*out*/ TrustLevel& trustLevel);
+
+Result CheckNameConstraints(Input encodedNameConstraints,
+                            const BackCert& firstChild,
+                            KeyPurposeId requiredEKUIfPresent);
+
+Result CheckIssuer(Input encodedIssuer);
+
+// ParseValidity and CheckValidity are usually used together.  First you parse
+// the dates from the DER Validity sequence, then you compare them to the time
+// at which you are validating.  They are separate so that the notBefore and
+// notAfter times can be used for other things before they are checked against
+// the time of validation.
+Result ParseValidity(Input encodedValidity,
+                     /*optional out*/ Time* notBeforeOut = nullptr,
+                     /*optional out*/ Time* notAfterOut = nullptr);
+Result CheckValidity(Time time, Time notBefore, Time notAfter);
+
+// Check that a subject has TLS Feature (rfc7633) requirements that match its
+// potential issuer
+Result CheckTLSFeatures(const BackCert& subject, BackCert& potentialIssuer);
+
+} } // namespace mozilla::pkix
+
+#endif // mozilla_pkix_pkixcheck_h
diff --git a/security/pkix/lib/pkixder.cpp b/security/pkix/lib/pkixder.cpp
new file mode 100644
index 000000000..0660b42b2
--- /dev/null
+++ b/security/pkix/lib/pkixder.cpp
@@ -0,0 +1,612 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkixder.h"
+
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix { namespace der {
+
+// Too complicated to be inline
+Result
+ReadTagAndGetValue(Reader& input, /*out*/ uint8_t& tag, /*out*/ Input& value)
+{
+  Result rv;
+
+  rv = input.Read(tag);
+  if (rv != Success) {
+    return rv;
+  }
+  if ((tag & 0x1F) == 0x1F) {
+    return Result::ERROR_BAD_DER; // high tag number form not allowed
+  }
+
+  uint16_t length;
+
+  // The short form of length is a single byte with the high order bit set
+  // to zero. The long form of length is one byte with the high order bit
+  // set, followed by N bytes, where N is encoded in the lowest 7 bits of
+  // the first byte.
+  uint8_t length1;
+  rv = input.Read(length1);
+  if (rv != Success) {
+    return rv;
+  }
+  if (!(length1 & 0x80)) {
+    length = length1;
+  } else if (length1 == 0x81) {
+    uint8_t length2;
+    rv = input.Read(length2);
+    if (rv != Success) {
+      return rv;
+    }
+    if (length2 < 128) {
+      // Not shortest possible encoding
+      return Result::ERROR_BAD_DER;
+    }
+    length = length2;
+  } else if (length1 == 0x82) {
+    rv = input.Read(length);
+    if (rv != Success) {
+      return rv;
+    }
+    if (length < 256) {
+      // Not shortest possible encoding
+      return Result::ERROR_BAD_DER;
+    }
+  } else {
+    // We don't support lengths larger than 2^16 - 1.
+    return Result::ERROR_BAD_DER;
+  }
+
+  return input.Skip(length, value);
+}
+
+static Result
+OptionalNull(Reader& input)
+{
+  if (input.Peek(NULLTag)) {
+    return Null(input);
+  }
+  return Success;
+}
+
+namespace {
+
+Result
+AlgorithmIdentifierValue(Reader& input, /*out*/ Reader& algorithmOIDValue)
+{
+  Result rv = ExpectTagAndGetValue(input, der::OIDTag, algorithmOIDValue);
+  if (rv != Success) {
+    return rv;
+  }
+  return OptionalNull(input);
+}
+
+} // namespace
+
+Result
+SignatureAlgorithmIdentifierValue(Reader& input,
+                                 /*out*/ PublicKeyAlgorithm& publicKeyAlgorithm,
+                                 /*out*/ DigestAlgorithm& digestAlgorithm)
+{
+  // RFC 5758 Section 3.2 (ECDSA with SHA-2), and RFC 3279 Section 2.2.3
+  // (ECDSA with SHA-1) say that parameters must be omitted.
+  //
+  // RFC 4055 Section 5 and RFC 3279 Section 2.2.1 both say that parameters for
+  // RSA must be encoded as NULL; we relax that requirement by allowing the
+  // NULL to be omitted, to match all the other signature algorithms we support
+  // and for compatibility.
+  Reader algorithmID;
+  Result rv = AlgorithmIdentifierValue(input, algorithmID);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // RFC 5758 Section 3.2 (ecdsa-with-SHA224 is intentionally excluded)
+  // python DottedOIDToCode.py ecdsa-with-SHA256 1.2.840.10045.4.3.2
+  static const uint8_t ecdsa_with_SHA256[] = {
+    0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x02
+  };
+  // python DottedOIDToCode.py ecdsa-with-SHA384 1.2.840.10045.4.3.3
+  static const uint8_t ecdsa_with_SHA384[] = {
+    0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x03
+  };
+  // python DottedOIDToCode.py ecdsa-with-SHA512 1.2.840.10045.4.3.4
+  static const uint8_t ecdsa_with_SHA512[] = {
+    0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x04
+  };
+
+  // RFC 4055 Section 5 (sha224WithRSAEncryption is intentionally excluded)
+  // python DottedOIDToCode.py sha256WithRSAEncryption 1.2.840.113549.1.1.11
+  static const uint8_t sha256WithRSAEncryption[] = {
+    0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x0b
+  };
+  // python DottedOIDToCode.py sha384WithRSAEncryption 1.2.840.113549.1.1.12
+  static const uint8_t sha384WithRSAEncryption[] = {
+    0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x0c
+  };
+  // python DottedOIDToCode.py sha512WithRSAEncryption 1.2.840.113549.1.1.13
+  static const uint8_t sha512WithRSAEncryption[] = {
+    0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x0d
+  };
+
+  // RFC 3279 Section 2.2.1
+  // python DottedOIDToCode.py sha-1WithRSAEncryption 1.2.840.113549.1.1.5
+  static const uint8_t sha_1WithRSAEncryption[] = {
+    0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05
+  };
+
+  // NIST Open Systems Environment (OSE) Implementor's Workshop (OIW)
+  // http://www.oiw.org/agreements/stable/12s-9412.txt (no longer works).
+  // http://www.imc.org/ietf-pkix/old-archive-97/msg01166.html
+  // We need to support this this non-PKIX OID for compatibility.
+  // python DottedOIDToCode.py sha1WithRSASignature 1.3.14.3.2.29
+  static const uint8_t sha1WithRSASignature[] = {
+    0x2b, 0x0e, 0x03, 0x02, 0x1d
+  };
+
+  // RFC 3279 Section 2.2.3
+  // python DottedOIDToCode.py ecdsa-with-SHA1 1.2.840.10045.4.1
+  static const uint8_t ecdsa_with_SHA1[] = {
+    0x2a, 0x86, 0x48, 0xce, 0x3d, 0x04, 0x01
+  };
+
+  // Matching is attempted based on a rough estimate of the commonality of the
+  // algorithm, to minimize the number of MatchRest calls.
+  if (algorithmID.MatchRest(sha256WithRSAEncryption)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::RSA_PKCS1;
+    digestAlgorithm = DigestAlgorithm::sha256;
+  } else if (algorithmID.MatchRest(ecdsa_with_SHA256)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::ECDSA;
+    digestAlgorithm = DigestAlgorithm::sha256;
+  } else if (algorithmID.MatchRest(sha_1WithRSAEncryption)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::RSA_PKCS1;
+    digestAlgorithm = DigestAlgorithm::sha1;
+  } else if (algorithmID.MatchRest(ecdsa_with_SHA1)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::ECDSA;
+    digestAlgorithm = DigestAlgorithm::sha1;
+  } else if (algorithmID.MatchRest(ecdsa_with_SHA384)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::ECDSA;
+    digestAlgorithm = DigestAlgorithm::sha384;
+  } else if (algorithmID.MatchRest(ecdsa_with_SHA512)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::ECDSA;
+    digestAlgorithm = DigestAlgorithm::sha512;
+  } else if (algorithmID.MatchRest(sha384WithRSAEncryption)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::RSA_PKCS1;
+    digestAlgorithm = DigestAlgorithm::sha384;
+  } else if (algorithmID.MatchRest(sha512WithRSAEncryption)) {
+    publicKeyAlgorithm = PublicKeyAlgorithm::RSA_PKCS1;
+    digestAlgorithm = DigestAlgorithm::sha512;
+  } else if (algorithmID.MatchRest(sha1WithRSASignature)) {
+    // XXX(bug 1042479): recognize this old OID for compatibility.
+    publicKeyAlgorithm = PublicKeyAlgorithm::RSA_PKCS1;
+    digestAlgorithm = DigestAlgorithm::sha1;
+  } else {
+    return Result::ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED;
+  }
+
+  return Success;
+}
+
+Result
+DigestAlgorithmIdentifier(Reader& input, /*out*/ DigestAlgorithm& algorithm)
+{
+  Reader r;
+  return der::Nested(input, SEQUENCE, [&algorithm](Reader& r) -> Result {
+    Reader algorithmID;
+    Result rv = AlgorithmIdentifierValue(r, algorithmID);
+    if (rv != Success) {
+      return rv;
+    }
+
+    // RFC 4055 Section 2.1
+    // python DottedOIDToCode.py id-sha1 1.3.14.3.2.26
+    static const uint8_t id_sha1[] = {
+      0x2b, 0x0e, 0x03, 0x02, 0x1a
+    };
+    // python DottedOIDToCode.py id-sha256 2.16.840.1.101.3.4.2.1
+    static const uint8_t id_sha256[] = {
+      0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01
+    };
+    // python DottedOIDToCode.py id-sha384 2.16.840.1.101.3.4.2.2
+    static const uint8_t id_sha384[] = {
+      0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02
+    };
+    // python DottedOIDToCode.py id-sha512 2.16.840.1.101.3.4.2.3
+    static const uint8_t id_sha512[] = {
+      0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03
+    };
+
+    // Matching is attempted based on a rough estimate of the commonality of the
+    // algorithm, to minimize the number of MatchRest calls.
+    if (algorithmID.MatchRest(id_sha1)) {
+      algorithm = DigestAlgorithm::sha1;
+    } else if (algorithmID.MatchRest(id_sha256)) {
+      algorithm = DigestAlgorithm::sha256;
+    } else if (algorithmID.MatchRest(id_sha384)) {
+      algorithm = DigestAlgorithm::sha384;
+    } else if (algorithmID.MatchRest(id_sha512)) {
+      algorithm = DigestAlgorithm::sha512;
+    } else {
+      return Result::ERROR_INVALID_ALGORITHM;
+    }
+
+    return Success;
+  });
+}
+
+Result
+SignedData(Reader& input, /*out*/ Reader& tbs,
+           /*out*/ SignedDataWithSignature& signedData)
+{
+  Reader::Mark mark(input.GetMark());
+
+  Result rv;
+  rv = ExpectTagAndGetValue(input, SEQUENCE, tbs);
+  if (rv != Success) {
+    return rv;
+  }
+
+  rv = input.GetInput(mark, signedData.data);
+  if (rv != Success) {
+    return rv;
+  }
+
+  rv = ExpectTagAndGetValue(input, der::SEQUENCE, signedData.algorithm);
+  if (rv != Success) {
+    return rv;
+  }
+
+  rv = BitStringWithNoUnusedBits(input, signedData.signature);
+  if (rv == Result::ERROR_BAD_DER) {
+    rv = Result::ERROR_BAD_SIGNATURE;
+  }
+  return rv;
+}
+
+Result
+BitStringWithNoUnusedBits(Reader& input, /*out*/ Input& value)
+{
+  Reader valueWithUnusedBits;
+  Result rv = ExpectTagAndGetValue(input, BIT_STRING, valueWithUnusedBits);
+  if (rv != Success) {
+    return rv;
+  }
+
+  uint8_t unusedBitsAtEnd;
+  if (valueWithUnusedBits.Read(unusedBitsAtEnd) != Success) {
+    return Result::ERROR_BAD_DER;
+  }
+  // XXX: Really the constraint should be that unusedBitsAtEnd must be less
+  // than 7. But, we suspect there are no real-world values in OCSP responses
+  // or certificates with non-zero unused bits. It seems like NSS assumes this
+  // in various places, so we enforce it too in order to simplify this code. If
+  // we find compatibility issues, we'll know we're wrong and we'll have to
+  // figure out how to shift the bits around.
+  if (unusedBitsAtEnd != 0) {
+    return Result::ERROR_BAD_DER;
+  }
+  return valueWithUnusedBits.SkipToEnd(value);
+}
+
+static inline Result
+ReadDigit(Reader& input, /*out*/ unsigned int& value)
+{
+  uint8_t b;
+  if (input.Read(b) != Success) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+  if (b < '0' || b > '9') {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+  value = static_cast<unsigned int>(b - static_cast<uint8_t>('0'));
+  return Success;
+}
+
+static inline Result
+ReadTwoDigits(Reader& input, unsigned int minValue, unsigned int maxValue,
+              /*out*/ unsigned int& value)
+{
+  unsigned int hi;
+  Result rv = ReadDigit(input, hi);
+  if (rv != Success) {
+    return rv;
+  }
+  unsigned int lo;
+  rv = ReadDigit(input, lo);
+  if (rv != Success) {
+    return rv;
+  }
+  value = (hi * 10) + lo;
+  if (value < minValue || value > maxValue) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+  return Success;
+}
+
+namespace internal {
+
+// We parse GeneralizedTime and UTCTime according to RFC 5280 and we do not
+// accept all time formats allowed in the ASN.1 spec. That is,
+// GeneralizedTime must always be in the format YYYYMMDDHHMMSSZ and UTCTime
+// must always be in the format YYMMDDHHMMSSZ. Timezone formats of the form
+// +HH:MM or -HH:MM or NOT accepted.
+Result
+TimeChoice(Reader& tagged, uint8_t expectedTag, /*out*/ Time& time)
+{
+  unsigned int days;
+
+  Reader input;
+  Result rv = ExpectTagAndGetValue(tagged, expectedTag, input);
+  if (rv != Success) {
+    return rv;
+  }
+
+  unsigned int yearHi;
+  unsigned int yearLo;
+  if (expectedTag == GENERALIZED_TIME) {
+    rv = ReadTwoDigits(input, 0, 99, yearHi);
+    if (rv != Success) {
+      return rv;
+    }
+    rv = ReadTwoDigits(input, 0, 99, yearLo);
+    if (rv != Success) {
+      return rv;
+    }
+  } else if (expectedTag == UTCTime) {
+    rv = ReadTwoDigits(input, 0, 99, yearLo);
+    if (rv != Success) {
+      return rv;
+    }
+    yearHi = yearLo >= 50u ? 19u : 20u;
+  } else {
+    return NotReached("invalid tag given to TimeChoice",
+                      Result::ERROR_INVALID_DER_TIME);
+  }
+  unsigned int year = (yearHi * 100u) + yearLo;
+  if (year < 1970u) {
+    // We don't support dates before January 1, 1970 because that is the epoch.
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+  days = DaysBeforeYear(year);
+
+  unsigned int month;
+  rv = ReadTwoDigits(input, 1u, 12u, month);
+  if (rv != Success) {
+    return rv;
+  }
+  unsigned int daysInMonth;
+  static const unsigned int jan = 31u;
+  const unsigned int feb = ((year % 4u == 0u) &&
+                           ((year % 100u != 0u) || (year % 400u == 0u)))
+                         ? 29u
+                         : 28u;
+  static const unsigned int mar = 31u;
+  static const unsigned int apr = 30u;
+  static const unsigned int may = 31u;
+  static const unsigned int jun = 30u;
+  static const unsigned int jul = 31u;
+  static const unsigned int aug = 31u;
+  static const unsigned int sep = 30u;
+  static const unsigned int oct = 31u;
+  static const unsigned int nov = 30u;
+  static const unsigned int dec = 31u;
+  switch (month) {
+    case 1:  daysInMonth = jan; break;
+    case 2:  daysInMonth = feb; days += jan; break;
+    case 3:  daysInMonth = mar; days += jan + feb; break;
+    case 4:  daysInMonth = apr; days += jan + feb + mar; break;
+    case 5:  daysInMonth = may; days += jan + feb + mar + apr; break;
+    case 6:  daysInMonth = jun; days += jan + feb + mar + apr + may; break;
+    case 7:  daysInMonth = jul; days += jan + feb + mar + apr + may + jun;
+             break;
+    case 8:  daysInMonth = aug; days += jan + feb + mar + apr + may + jun +
+                                        jul;
+             break;
+    case 9:  daysInMonth = sep; days += jan + feb + mar + apr + may + jun +
+                                        jul + aug;
+             break;
+    case 10: daysInMonth = oct; days += jan + feb + mar + apr + may + jun +
+                                        jul + aug + sep;
+             break;
+    case 11: daysInMonth = nov; days += jan + feb + mar + apr + may + jun +
+                                        jul + aug + sep + oct;
+             break;
+    case 12: daysInMonth = dec; days += jan + feb + mar + apr + may + jun +
+                                        jul + aug + sep + oct + nov;
+             break;
+    default:
+      return NotReached("month already bounds-checked by ReadTwoDigits",
+                        Result::FATAL_ERROR_INVALID_STATE);
+  }
+
+  unsigned int dayOfMonth;
+  rv = ReadTwoDigits(input, 1u, daysInMonth, dayOfMonth);
+  if (rv != Success) {
+    return rv;
+  }
+  days += dayOfMonth - 1;
+
+  unsigned int hours;
+  rv = ReadTwoDigits(input, 0u, 23u, hours);
+  if (rv != Success) {
+    return rv;
+  }
+  unsigned int minutes;
+  rv = ReadTwoDigits(input, 0u, 59u, minutes);
+  if (rv != Success) {
+    return rv;
+  }
+  unsigned int seconds;
+  rv = ReadTwoDigits(input, 0u, 59u, seconds);
+  if (rv != Success) {
+    return rv;
+  }
+
+  uint8_t b;
+  if (input.Read(b) != Success) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+  if (b != 'Z') {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+  if (End(input) != Success) {
+    return Result::ERROR_INVALID_DER_TIME;
+  }
+
+  uint64_t totalSeconds = (static_cast<uint64_t>(days) * 24u * 60u * 60u) +
+                          (static_cast<uint64_t>(hours)      * 60u * 60u) +
+                          (static_cast<uint64_t>(minutes)          * 60u) +
+                          seconds;
+
+  time = TimeFromElapsedSecondsAD(totalSeconds);
+  return Success;
+}
+
+Result
+IntegralBytes(Reader& input, uint8_t tag,
+              IntegralValueRestriction valueRestriction,
+              /*out*/ Input& value,
+              /*optional out*/ Input::size_type* significantBytes)
+{
+  Result rv = ExpectTagAndGetValue(input, tag, value);
+  if (rv != Success) {
+    return rv;
+  }
+  Reader reader(value);
+
+  // There must be at least one byte in the value. (Zero is encoded with a
+  // single 0x00 value byte.)
+  uint8_t firstByte;
+  rv = reader.Read(firstByte);
+  if (rv != Success) {
+    if (rv == Result::ERROR_BAD_DER) {
+      return Result::ERROR_INVALID_INTEGER_ENCODING;
+    }
+
+    return rv;
+  }
+
+  // If there is a byte after an initial 0x00/0xFF, then the initial byte
+  // indicates a positive/negative integer value with its high bit set/unset.
+  bool prefixed = !reader.AtEnd() && (firstByte == 0 || firstByte == 0xff);
+
+  if (prefixed) {
+    uint8_t nextByte;
+    if (reader.Read(nextByte) != Success) {
+      return NotReached("Read of one byte failed but not at end.",
+                        Result::FATAL_ERROR_LIBRARY_FAILURE);
+    }
+    if ((firstByte & 0x80) == (nextByte & 0x80)) {
+      return Result::ERROR_INVALID_INTEGER_ENCODING;
+    }
+  }
+
+  switch (valueRestriction) {
+    case IntegralValueRestriction::MustBe0To127:
+      if (value.GetLength() != 1 || (firstByte & 0x80) != 0) {
+        return Result::ERROR_INVALID_INTEGER_ENCODING;
+      }
+      break;
+
+    case IntegralValueRestriction::MustBePositive:
+      if ((value.GetLength() == 1 && firstByte == 0) ||
+          (firstByte & 0x80) != 0) {
+        return Result::ERROR_INVALID_INTEGER_ENCODING;
+      }
+      break;
+
+    case IntegralValueRestriction::NoRestriction:
+      break;
+  }
+
+  if (significantBytes) {
+    *significantBytes = value.GetLength();
+    if (prefixed) {
+      assert(*significantBytes > 1);
+      --*significantBytes;
+    }
+
+    assert(*significantBytes > 0);
+  }
+
+  return Success;
+}
+
+// This parser will only parse values between 0..127. If this range is
+// increased then callers will need to be changed.
+Result
+IntegralValue(Reader& input, uint8_t tag, /*out*/ uint8_t& value)
+{
+  // Conveniently, all the Integers that we actually have to be able to parse
+  // are positive and very small. Consequently, this parser is *much* simpler
+  // than a general Integer parser would need to be.
+  Input valueBytes;
+  Result rv = IntegralBytes(input, tag, IntegralValueRestriction::MustBe0To127,
+                            valueBytes, nullptr);
+  if (rv != Success) {
+    return rv;
+  }
+  Reader valueReader(valueBytes);
+  rv = valueReader.Read(value);
+  if (rv != Success) {
+    return NotReached("IntegralBytes already validated the value.", rv);
+  }
+  rv = End(valueReader);
+  assert(rv == Success); // guaranteed by IntegralBytes's range checks.
+  return rv;
+}
+
+} // namespace internal
+
+Result
+OptionalVersion(Reader& input, /*out*/ Version& version)
+{
+  static const uint8_t TAG = CONTEXT_SPECIFIC | CONSTRUCTED | 0;
+  if (!input.Peek(TAG)) {
+    version = Version::v1;
+    return Success;
+  }
+  return Nested(input, TAG, [&version](Reader& value) -> Result {
+    uint8_t integerValue;
+    Result rv = Integer(value, integerValue);
+    if (rv != Success) {
+      return rv;
+    }
+    // XXX(bug 1031093): We shouldn't accept an explicit encoding of v1,
+    // but we do here for compatibility reasons.
+    switch (integerValue) {
+      case static_cast<uint8_t>(Version::v3): version = Version::v3; break;
+      case static_cast<uint8_t>(Version::v2): version = Version::v2; break;
+      case static_cast<uint8_t>(Version::v1): version = Version::v1; break;
+      case static_cast<uint8_t>(Version::v4): version = Version::v4; break;
+      default:
+        return Result::ERROR_BAD_DER;
+    }
+    return Success;
+  });
+}
+
+} } } // namespace mozilla::pkix::der
diff --git a/security/pkix/lib/pkixder.h b/security/pkix/lib/pkixder.h
new file mode 100644
index 000000000..a17114bcb
--- /dev/null
+++ b/security/pkix/lib/pkixder.h
@@ -0,0 +1,565 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef mozilla_pkix_pkixder_h
+#define mozilla_pkix_pkixder_h
+
+// Expect* functions advance the input mark and return Success if the input
+// matches the given criteria; they fail with the input mark in an undefined
+// state if the input does not match the criteria.
+//
+// Match* functions advance the input mark and return true if the input matches
+// the given criteria; they return false without changing the input mark if the
+// input does not match the criteria.
+//
+// Skip* functions unconditionally advance the input mark and return Success if
+// they are able to do so; otherwise they fail with the input mark in an
+// undefined state.
+
+#include "pkix/Input.h"
+#include "pkix/pkixtypes.h"
+
+namespace mozilla { namespace pkix { namespace der {
+
+enum Class : uint8_t
+{
+   UNIVERSAL = 0 << 6,
+// APPLICATION = 1 << 6, // unused
+   CONTEXT_SPECIFIC = 2 << 6,
+// PRIVATE = 3 << 6 // unused
+};
+
+enum Constructed
+{
+  CONSTRUCTED = 1 << 5
+};
+
+enum Tag : uint8_t
+{
+  BOOLEAN = UNIVERSAL | 0x01,
+  INTEGER = UNIVERSAL | 0x02,
+  BIT_STRING = UNIVERSAL | 0x03,
+  OCTET_STRING = UNIVERSAL | 0x04,
+  NULLTag = UNIVERSAL | 0x05,
+  OIDTag = UNIVERSAL | 0x06,
+  ENUMERATED = UNIVERSAL | 0x0a,
+  UTF8String = UNIVERSAL | 0x0c,
+  SEQUENCE = UNIVERSAL | CONSTRUCTED | 0x10, // 0x30
+  SET = UNIVERSAL | CONSTRUCTED | 0x11, // 0x31
+  PrintableString = UNIVERSAL | 0x13,
+  TeletexString = UNIVERSAL | 0x14,
+  IA5String = UNIVERSAL | 0x16,
+  UTCTime = UNIVERSAL | 0x17,
+  GENERALIZED_TIME = UNIVERSAL | 0x18,
+};
+
+enum class EmptyAllowed { No = 0, Yes = 1 };
+
+Result ReadTagAndGetValue(Reader& input, /*out*/ uint8_t& tag,
+                          /*out*/ Input& value);
+Result End(Reader& input);
+
+inline Result
+ExpectTagAndGetValue(Reader& input, uint8_t tag, /*out*/ Input& value)
+{
+  uint8_t actualTag;
+  Result rv = ReadTagAndGetValue(input, actualTag, value);
+  if (rv != Success) {
+    return rv;
+  }
+  if (tag != actualTag) {
+    return Result::ERROR_BAD_DER;
+  }
+  return Success;
+}
+
+inline Result
+ExpectTagAndGetValue(Reader& input, uint8_t tag, /*out*/ Reader& value)
+{
+  Input valueInput;
+  Result rv = ExpectTagAndGetValue(input, tag, valueInput);
+  if (rv != Success) {
+    return rv;
+  }
+  return value.Init(valueInput);
+}
+
+inline Result
+ExpectTagAndEmptyValue(Reader& input, uint8_t tag)
+{
+  Reader value;
+  Result rv = ExpectTagAndGetValue(input, tag, value);
+  if (rv != Success) {
+    return rv;
+  }
+  return End(value);
+}
+
+inline Result
+ExpectTagAndSkipValue(Reader& input, uint8_t tag)
+{
+  Input ignoredValue;
+  return ExpectTagAndGetValue(input, tag, ignoredValue);
+}
+
+// Like ExpectTagAndGetValue, except the output Input will contain the
+// encoded tag and length along with the value.
+inline Result
+ExpectTagAndGetTLV(Reader& input, uint8_t tag, /*out*/ Input& tlv)
+{
+  Reader::Mark mark(input.GetMark());
+  Result rv = ExpectTagAndSkipValue(input, tag);
+  if (rv != Success) {
+    return rv;
+  }
+  return input.GetInput(mark, tlv);
+}
+
+inline Result
+End(Reader& input)
+{
+  if (!input.AtEnd()) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  return Success;
+}
+
+template <typename Decoder>
+inline Result
+Nested(Reader& input, uint8_t tag, Decoder decoder)
+{
+  Reader nested;
+  Result rv = ExpectTagAndGetValue(input, tag, nested);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = decoder(nested);
+  if (rv != Success) {
+    return rv;
+  }
+  return End(nested);
+}
+
+template <typename Decoder>
+inline Result
+Nested(Reader& input, uint8_t outerTag, uint8_t innerTag, Decoder decoder)
+{
+  Reader nestedInput;
+  Result rv = ExpectTagAndGetValue(input, outerTag, nestedInput);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = Nested(nestedInput, innerTag, decoder);
+  if (rv != Success) {
+    return rv;
+  }
+  return End(nestedInput);
+}
+
+// This can be used to decode constructs like this:
+//
+//     ...
+//     foos SEQUENCE OF Foo,
+//     ...
+//     Foo ::= SEQUENCE {
+//     }
+//
+// using code like this:
+//
+//    Result Foo(Reader& r) { /*...*/ }
+//
+//    rv = der::NestedOf(input, der::SEQEUENCE, der::SEQUENCE, Foo);
+//
+// or:
+//
+//    Result Bar(Reader& r, int value) { /*...*/ }
+//
+//    int value = /*...*/;
+//
+//    rv = der::NestedOf(input, der::SEQUENCE, [value](Reader& r) {
+//      return Bar(r, value);
+//    });
+//
+// In these examples the function will get called once for each element of
+// foos.
+//
+template <typename Decoder>
+inline Result
+NestedOf(Reader& input, uint8_t outerTag, uint8_t innerTag,
+         EmptyAllowed mayBeEmpty, Decoder decoder)
+{
+  Reader inner;
+  Result rv = ExpectTagAndGetValue(input, outerTag, inner);
+  if (rv != Success) {
+    return rv;
+  }
+
+  if (inner.AtEnd()) {
+    if (mayBeEmpty != EmptyAllowed::Yes) {
+      return Result::ERROR_BAD_DER;
+    }
+    return Success;
+  }
+
+  do {
+    rv = Nested(inner, innerTag, decoder);
+    if (rv != Success) {
+      return rv;
+    }
+  } while (!inner.AtEnd());
+
+  return Success;
+}
+
+// Often, a function will need to decode an Input or Reader that contains
+// DER-encoded data wrapped in a SEQUENCE (or similar) with nothing after it.
+// This function reduces the boilerplate necessary for stripping the outermost
+// SEQUENCE (or similar) and ensuring that nothing follows it.
+inline Result
+ExpectTagAndGetValueAtEnd(Reader& outer, uint8_t expectedTag,
+                          /*out*/ Reader& inner)
+{
+  Result rv = der::ExpectTagAndGetValue(outer, expectedTag, inner);
+  if (rv != Success) {
+    return rv;
+  }
+  return der::End(outer);
+}
+
+// Similar to the above, but takes an Input instead of a Reader&.
+inline Result
+ExpectTagAndGetValueAtEnd(Input outer, uint8_t expectedTag,
+                          /*out*/ Reader& inner)
+{
+  Reader outerReader(outer);
+  return ExpectTagAndGetValueAtEnd(outerReader, expectedTag, inner);
+}
+
+// Universal types
+
+namespace internal {
+
+enum class IntegralValueRestriction
+{
+  NoRestriction,
+  MustBePositive,
+  MustBe0To127,
+};
+
+Result IntegralBytes(Reader& input, uint8_t tag,
+                     IntegralValueRestriction valueRestriction,
+             /*out*/ Input& value,
+    /*optional out*/ Input::size_type* significantBytes = nullptr);
+
+// This parser will only parse values between 0..127. If this range is
+// increased then callers will need to be changed.
+Result IntegralValue(Reader& input, uint8_t tag, /*out*/ uint8_t& value);
+
+} // namespace internal
+
+Result
+BitStringWithNoUnusedBits(Reader& input, /*out*/ Input& value);
+
+inline Result
+Boolean(Reader& input, /*out*/ bool& value)
+{
+  Reader valueReader;
+  Result rv = ExpectTagAndGetValue(input, BOOLEAN, valueReader);
+  if (rv != Success) {
+    return rv;
+  }
+
+  uint8_t intValue;
+  rv = valueReader.Read(intValue);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = End(valueReader);
+  if (rv != Success) {
+    return rv;
+  }
+  switch (intValue) {
+    case 0: value = false; return Success;
+    case 0xFF: value = true; return Success;
+    default:
+      return Result::ERROR_BAD_DER;
+  }
+}
+
+// This is for BOOLEAN DEFAULT FALSE.
+// The standard stipulates that "The encoding of a set value or sequence value
+// shall not include an encoding for any component value which is equal to its
+// default value." However, it appears to be common that other libraries
+// incorrectly include the value of a BOOLEAN even when it's equal to the
+// default value, so we allow invalid explicit encodings here.
+inline Result
+OptionalBoolean(Reader& input, /*out*/ bool& value)
+{
+  value = false;
+  if (input.Peek(BOOLEAN)) {
+    Result rv = Boolean(input, value);
+    if (rv != Success) {
+      return rv;
+    }
+  }
+  return Success;
+}
+
+// This parser will only parse values between 0..127. If this range is
+// increased then callers will need to be changed.
+inline Result
+Enumerated(Reader& input, uint8_t& value)
+{
+  return internal::IntegralValue(input, ENUMERATED | 0, value);
+}
+
+namespace internal {
+
+// internal::TimeChoice implements the shared functionality of GeneralizedTime
+// and TimeChoice. tag must be either UTCTime or GENERALIZED_TIME.
+//
+// Only times from 1970-01-01-00:00:00 onward are accepted, in order to
+// eliminate the chance for complications in converting times to traditional
+// time formats that start at 1970.
+Result TimeChoice(Reader& input, uint8_t tag, /*out*/ Time& time);
+
+} // namespace internal
+
+// Only times from 1970-01-01-00:00:00 onward are accepted, in order to
+// eliminate the chance for complications in converting times to traditional
+// time formats that start at 1970.
+inline Result
+GeneralizedTime(Reader& input, /*out*/ Time& time)
+{
+  return internal::TimeChoice(input, GENERALIZED_TIME, time);
+}
+
+// Only times from 1970-01-01-00:00:00 onward are accepted, in order to
+// eliminate the chance for complications in converting times to traditional
+// time formats that start at 1970.
+inline Result
+TimeChoice(Reader& input, /*out*/ Time& time)
+{
+  uint8_t expectedTag = input.Peek(UTCTime) ? UTCTime : GENERALIZED_TIME;
+  return internal::TimeChoice(input, expectedTag, time);
+}
+
+// Parse a DER integer value into value. Empty values, negative values, and
+// zero are rejected. If significantBytes is not null, then it will be set to
+// the number of significant bytes in the value (the length of the value, less
+// the length of any leading padding), which is useful for key size checks.
+inline Result
+PositiveInteger(Reader& input, /*out*/ Input& value,
+                /*optional out*/ Input::size_type* significantBytes = nullptr)
+{
+  return internal::IntegralBytes(
+           input, INTEGER, internal::IntegralValueRestriction::MustBePositive,
+           value, significantBytes);
+}
+
+// This parser will only parse values between 0..127. If this range is
+// increased then callers will need to be changed.
+inline Result
+Integer(Reader& input, /*out*/ uint8_t& value)
+{
+  return internal::IntegralValue(input, INTEGER, value);
+}
+
+// This parser will only parse values between 0..127. If this range is
+// increased then callers will need to be changed. The default value must be
+// -1; defaultValue is only a parameter to make it clear in the calling code
+// what the default value is.
+inline Result
+OptionalInteger(Reader& input, long defaultValue, /*out*/ long& value)
+{
+  // If we need to support a different default value in the future, we need to
+  // test that parsedValue != defaultValue.
+  if (defaultValue != -1) {
+    return Result::FATAL_ERROR_INVALID_ARGS;
+  }
+
+  if (!input.Peek(INTEGER)) {
+    value = defaultValue;
+    return Success;
+  }
+
+  uint8_t parsedValue;
+  Result rv = Integer(input, parsedValue);
+  if (rv != Success) {
+    return rv;
+  }
+  value = parsedValue;
+  return Success;
+}
+
+inline Result
+Null(Reader& input)
+{
+  return ExpectTagAndEmptyValue(input, NULLTag);
+}
+
+template <uint8_t Len>
+Result
+OID(Reader& input, const uint8_t (&expectedOid)[Len])
+{
+  Reader value;
+  Result rv = ExpectTagAndGetValue(input, OIDTag, value);
+  if (rv != Success) {
+    return rv;
+  }
+  if (!value.MatchRest(expectedOid)) {
+    return Result::ERROR_BAD_DER;
+  }
+  return Success;
+}
+
+// PKI-specific types
+
+inline Result
+CertificateSerialNumber(Reader& input, /*out*/ Input& value)
+{
+  // http://tools.ietf.org/html/rfc5280#section-4.1.2.2:
+  //
+  // * "The serial number MUST be a positive integer assigned by the CA to
+  //   each certificate."
+  // * "Certificate users MUST be able to handle serialNumber values up to 20
+  //   octets. Conforming CAs MUST NOT use serialNumber values longer than 20
+  //   octets."
+  // * "Note: Non-conforming CAs may issue certificates with serial numbers
+  //   that are negative or zero.  Certificate users SHOULD be prepared to
+  //   gracefully handle such certificates."
+  return internal::IntegralBytes(
+           input, INTEGER, internal::IntegralValueRestriction::NoRestriction,
+           value);
+}
+
+// x.509 and OCSP both use this same version numbering scheme, though OCSP
+// only supports v1.
+enum class Version { v1 = 0, v2 = 1, v3 = 2, v4 = 3 };
+
+// X.509 Certificate and OCSP ResponseData both use
+// "[0] EXPLICIT Version DEFAULT v1". Although an explicit encoding of v1 is
+// illegal, we support it because some real-world OCSP responses explicitly
+// encode it.
+Result OptionalVersion(Reader& input, /*out*/ Version& version);
+
+template <typename ExtensionHandler>
+inline Result
+OptionalExtensions(Reader& input, uint8_t tag,
+                   ExtensionHandler extensionHandler)
+{
+  if (!input.Peek(tag)) {
+    return Success;
+  }
+
+  return Nested(input, tag, [extensionHandler](Reader& tagged) {
+    // Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
+    //
+    // TODO(bug 997994): According to the specification, there should never be
+    // an empty sequence of extensions but we've found OCSP responses that have
+    // that (see bug 991898).
+    return NestedOf(tagged, SEQUENCE, SEQUENCE, EmptyAllowed::Yes,
+                    [extensionHandler](Reader& extension) -> Result {
+      // Extension  ::=  SEQUENCE  {
+      //      extnID      OBJECT IDENTIFIER,
+      //      critical    BOOLEAN DEFAULT FALSE,
+      //      extnValue   OCTET STRING
+      //      }
+      Reader extnID;
+      Result rv = ExpectTagAndGetValue(extension, OIDTag, extnID);
+      if (rv != Success) {
+        return rv;
+      }
+      bool critical;
+      rv = OptionalBoolean(extension, critical);
+      if (rv != Success) {
+        return rv;
+      }
+      Input extnValue;
+      rv = ExpectTagAndGetValue(extension, OCTET_STRING, extnValue);
+      if (rv != Success) {
+        return rv;
+      }
+      bool understood = false;
+      rv = extensionHandler(extnID, extnValue, critical, understood);
+      if (rv != Success) {
+        return rv;
+      }
+      if (critical && !understood) {
+        return Result::ERROR_UNKNOWN_CRITICAL_EXTENSION;
+      }
+      return Success;
+    });
+  });
+}
+
+Result DigestAlgorithmIdentifier(Reader& input,
+                                 /*out*/ DigestAlgorithm& algorithm);
+
+enum class PublicKeyAlgorithm
+{
+  RSA_PKCS1,
+  ECDSA,
+};
+
+Result SignatureAlgorithmIdentifierValue(
+         Reader& input,
+         /*out*/ PublicKeyAlgorithm& publicKeyAlgorithm,
+         /*out*/ DigestAlgorithm& digestAlgorithm);
+
+struct SignedDataWithSignature final
+{
+public:
+  Input data;
+  Input algorithm;
+  Input signature;
+
+  void operator=(const SignedDataWithSignature&) = delete;
+};
+
+// Parses a SEQUENCE into tbs and then parses an AlgorithmIdentifier followed
+// by a BIT STRING into signedData. This handles the commonality between
+// parsing the signed/signature fields of certificates and OCSP responses. In
+// the case of an OCSP response, the caller needs to parse the certs
+// separately.
+//
+// Note that signatureAlgorithm is NOT parsed or validated.
+//
+// Certificate  ::=  SEQUENCE  {
+//        tbsCertificate       TBSCertificate,
+//        signatureAlgorithm   AlgorithmIdentifier,
+//        signatureValue       BIT STRING  }
+//
+// BasicOCSPResponse       ::= SEQUENCE {
+//    tbsResponseData      ResponseData,
+//    signatureAlgorithm   AlgorithmIdentifier,
+//    signature            BIT STRING,
+//    certs            [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL }
+Result SignedData(Reader& input, /*out*/ Reader& tbs,
+                  /*out*/ SignedDataWithSignature& signedDataWithSignature);
+
+} } } // namespace mozilla::pkix::der
+
+#endif // mozilla_pkix_pkixder_h
diff --git a/security/pkix/lib/pkixnames.cpp b/security/pkix/lib/pkixnames.cpp
new file mode 100644
index 000000000..ca9b8d7d3
--- /dev/null
+++ b/security/pkix/lib/pkixnames.cpp
@@ -0,0 +1,2050 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2014 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// This code implements RFC6125-ish name matching, RFC5280-ish name constraint
+// checking, and related things.
+//
+// In this code, identifiers are classified as either "presented" or
+// "reference" identifiers are defined in
+// http://tools.ietf.org/html/rfc6125#section-1.8. A "presented identifier" is
+// one in the subjectAltName of the certificate, or sometimes within a CN of
+// the certificate's subject. The "reference identifier" is the one we are
+// being asked to match the certificate against. When checking name
+// constraints, the reference identifier is the entire encoded name constraint
+// extension value.
+
+#include "pkixcheck.h"
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix {
+
+namespace {
+
+// GeneralName ::= CHOICE {
+//      otherName                       [0]     OtherName,
+//      rfc822Name                      [1]     IA5String,
+//      dNSName                         [2]     IA5String,
+//      x400Address                     [3]     ORAddress,
+//      directoryName                   [4]     Name,
+//      ediPartyName                    [5]     EDIPartyName,
+//      uniformResourceIdentifier       [6]     IA5String,
+//      iPAddress                       [7]     OCTET STRING,
+//      registeredID                    [8]     OBJECT IDENTIFIER }
+enum class GeneralNameType : uint8_t
+{
+  // Note that these values are NOT contiguous. Some values have the
+  // der::CONSTRUCTED bit set while others do not.
+  // (The der::CONSTRUCTED bit is for types where the value is a SEQUENCE.)
+  otherName = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 0,
+  rfc822Name = der::CONTEXT_SPECIFIC | 1,
+  dNSName = der::CONTEXT_SPECIFIC | 2,
+  x400Address = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 3,
+  directoryName = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 4,
+  ediPartyName = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 5,
+  uniformResourceIdentifier = der::CONTEXT_SPECIFIC | 6,
+  iPAddress = der::CONTEXT_SPECIFIC | 7,
+  registeredID = der::CONTEXT_SPECIFIC | 8,
+  // nameConstraints is a pseudo-GeneralName used to signify that a
+  // reference ID is actually the entire name constraint extension.
+  nameConstraints = 0xff
+};
+
+inline Result
+ReadGeneralName(Reader& reader,
+                /*out*/ GeneralNameType& generalNameType,
+                /*out*/ Input& value)
+{
+  uint8_t tag;
+  Result rv = der::ReadTagAndGetValue(reader, tag, value);
+  if (rv != Success) {
+    return rv;
+  }
+  switch (tag) {
+    case static_cast<uint8_t>(GeneralNameType::otherName):
+      generalNameType = GeneralNameType::otherName;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::rfc822Name):
+      generalNameType = GeneralNameType::rfc822Name;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::dNSName):
+      generalNameType = GeneralNameType::dNSName;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::x400Address):
+      generalNameType = GeneralNameType::x400Address;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::directoryName):
+      generalNameType = GeneralNameType::directoryName;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::ediPartyName):
+      generalNameType = GeneralNameType::ediPartyName;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::uniformResourceIdentifier):
+      generalNameType = GeneralNameType::uniformResourceIdentifier;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::iPAddress):
+      generalNameType = GeneralNameType::iPAddress;
+      break;
+    case static_cast<uint8_t>(GeneralNameType::registeredID):
+      generalNameType = GeneralNameType::registeredID;
+      break;
+    default:
+      return Result::ERROR_BAD_DER;
+  }
+  return Success;
+}
+
+enum class MatchResult
+{
+  NoNamesOfGivenType = 0,
+  Mismatch = 1,
+  Match = 2
+};
+
+Result SearchNames(const Input* subjectAltName, Input subject,
+                   GeneralNameType referenceIDType,
+                   Input referenceID,
+                   FallBackToSearchWithinSubject fallBackToCommonName,
+                   /*out*/ MatchResult& match);
+Result SearchWithinRDN(Reader& rdn,
+                       GeneralNameType referenceIDType,
+                       Input referenceID,
+                       FallBackToSearchWithinSubject fallBackToEmailAddress,
+                       FallBackToSearchWithinSubject fallBackToCommonName,
+                       /*in/out*/ MatchResult& match);
+Result MatchAVA(Input type,
+                uint8_t valueEncodingTag,
+                Input presentedID,
+                GeneralNameType referenceIDType,
+                Input referenceID,
+                FallBackToSearchWithinSubject fallBackToEmailAddress,
+                FallBackToSearchWithinSubject fallBackToCommonName,
+                /*in/out*/ MatchResult& match);
+Result ReadAVA(Reader& rdn,
+               /*out*/ Input& type,
+               /*out*/ uint8_t& valueTag,
+               /*out*/ Input& value);
+void MatchSubjectPresentedIDWithReferenceID(GeneralNameType presentedIDType,
+                                            Input presentedID,
+                                            GeneralNameType referenceIDType,
+                                            Input referenceID,
+                                            /*in/out*/ MatchResult& match);
+
+Result MatchPresentedIDWithReferenceID(GeneralNameType presentedIDType,
+                                       Input presentedID,
+                                       GeneralNameType referenceIDType,
+                                       Input referenceID,
+                                       /*in/out*/ MatchResult& matchResult);
+Result CheckPresentedIDConformsToConstraints(GeneralNameType referenceIDType,
+                                             Input presentedID,
+                                             Input nameConstraints);
+
+uint8_t LocaleInsensitveToLower(uint8_t a);
+bool StartsWithIDNALabel(Input id);
+
+enum class IDRole
+{
+  ReferenceID = 0,
+  PresentedID = 1,
+  NameConstraint = 2,
+};
+
+enum class AllowWildcards { No = 0, Yes = 1 };
+
+// DNSName constraints implicitly allow subdomain matching when there is no
+// leading dot ("foo.example.com" matches a constraint of "example.com"), but
+// RFC822Name constraints only allow subdomain matching when there is a leading
+// dot ("foo.example.com" does not match "example.com" but does match
+// ".example.com").
+enum class AllowDotlessSubdomainMatches { No = 0, Yes = 1 };
+
+bool IsValidDNSID(Input hostname, IDRole idRole,
+                  AllowWildcards allowWildcards);
+
+Result MatchPresentedDNSIDWithReferenceDNSID(
+         Input presentedDNSID,
+         AllowWildcards allowWildcards,
+         AllowDotlessSubdomainMatches allowDotlessSubdomainMatches,
+         IDRole referenceDNSIDRole,
+         Input referenceDNSID,
+         /*out*/ bool& matches);
+
+Result MatchPresentedRFC822NameWithReferenceRFC822Name(
+         Input presentedRFC822Name, IDRole referenceRFC822NameRole,
+         Input referenceRFC822Name, /*out*/ bool& matches);
+
+} // namespace
+
+bool IsValidReferenceDNSID(Input hostname);
+bool IsValidPresentedDNSID(Input hostname);
+bool ParseIPv4Address(Input hostname, /*out*/ uint8_t (&out)[4]);
+bool ParseIPv6Address(Input hostname, /*out*/ uint8_t (&out)[16]);
+
+// This is used by the pkixnames_tests.cpp tests.
+Result
+MatchPresentedDNSIDWithReferenceDNSID(Input presentedDNSID,
+                                      Input referenceDNSID,
+                                      /*out*/ bool& matches)
+{
+  return MatchPresentedDNSIDWithReferenceDNSID(
+           presentedDNSID, AllowWildcards::Yes,
+           AllowDotlessSubdomainMatches::Yes, IDRole::ReferenceID,
+           referenceDNSID, matches);
+}
+
+// Verify that the given end-entity cert, which is assumed to have been already
+// validated with BuildCertChain, is valid for the given hostname. hostname is
+// assumed to be a string representation of an IPv4 address, an IPv6 addresss,
+// or a normalized ASCII (possibly punycode) DNS name.
+Result
+CheckCertHostname(Input endEntityCertDER, Input hostname,
+                  NameMatchingPolicy& nameMatchingPolicy)
+{
+  BackCert cert(endEntityCertDER, EndEntityOrCA::MustBeEndEntity, nullptr);
+  Result rv = cert.Init();
+  if (rv != Success) {
+    return rv;
+  }
+
+  Time notBefore(Time::uninitialized);
+  rv = ParseValidity(cert.GetValidity(), &notBefore);
+  if (rv != Success) {
+    return rv;
+  }
+  FallBackToSearchWithinSubject fallBackToSearchWithinSubject;
+  rv = nameMatchingPolicy.FallBackToCommonName(notBefore,
+                                               fallBackToSearchWithinSubject);
+  if (rv != Success) {
+    return rv;
+  }
+
+  const Input* subjectAltName(cert.GetSubjectAltName());
+  Input subject(cert.GetSubject());
+
+  // For backward compatibility with legacy certificates, we may fall back to
+  // searching for a name match in the subject common name for DNS names and
+  // IPv4 addresses. We don't do so for IPv6 addresses because we do not think
+  // there are many certificates that would need such fallback, and because
+  // comparisons of string representations of IPv6 addresses are particularly
+  // error prone due to the syntactic flexibility that IPv6 addresses have.
+  //
+  // IPv4 and IPv6 addresses are represented using the same type of GeneralName
+  // (iPAddress); they are differentiated by the lengths of the values.
+  MatchResult match;
+  uint8_t ipv6[16];
+  uint8_t ipv4[4];
+  if (IsValidReferenceDNSID(hostname)) {
+    rv = SearchNames(subjectAltName, subject, GeneralNameType::dNSName,
+                     hostname, fallBackToSearchWithinSubject, match);
+  } else if (ParseIPv6Address(hostname, ipv6)) {
+    rv = SearchNames(subjectAltName, subject, GeneralNameType::iPAddress,
+                     Input(ipv6), FallBackToSearchWithinSubject::No, match);
+  } else if (ParseIPv4Address(hostname, ipv4)) {
+    rv = SearchNames(subjectAltName, subject, GeneralNameType::iPAddress,
+                     Input(ipv4), fallBackToSearchWithinSubject, match);
+  } else {
+    return Result::ERROR_BAD_CERT_DOMAIN;
+  }
+  if (rv != Success) {
+    return rv;
+  }
+  switch (match) {
+    case MatchResult::NoNamesOfGivenType: // fall through
+    case MatchResult::Mismatch:
+      return Result::ERROR_BAD_CERT_DOMAIN;
+    case MatchResult::Match:
+      return Success;
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+}
+
+// 4.2.1.10. Name Constraints
+Result
+CheckNameConstraints(Input encodedNameConstraints,
+                     const BackCert& firstChild,
+                     KeyPurposeId requiredEKUIfPresent)
+{
+  for (const BackCert* child = &firstChild; child; child = child->childCert) {
+    FallBackToSearchWithinSubject fallBackToCommonName
+      = (child->endEntityOrCA == EndEntityOrCA::MustBeEndEntity &&
+         requiredEKUIfPresent == KeyPurposeId::id_kp_serverAuth)
+      ? FallBackToSearchWithinSubject::Yes
+      : FallBackToSearchWithinSubject::No;
+
+    MatchResult match;
+    Result rv = SearchNames(child->GetSubjectAltName(), child->GetSubject(),
+                            GeneralNameType::nameConstraints,
+                            encodedNameConstraints, fallBackToCommonName,
+                            match);
+    if (rv != Success) {
+      return rv;
+    }
+    switch (match) {
+      case MatchResult::Match: // fall through
+      case MatchResult::NoNamesOfGivenType:
+        break;
+      case MatchResult::Mismatch:
+        return Result::ERROR_CERT_NOT_IN_NAME_SPACE;
+    }
+  }
+
+  return Success;
+}
+
+namespace {
+
+// SearchNames is used by CheckCertHostname and CheckNameConstraints.
+//
+// When called during name constraint checking, referenceIDType is
+// GeneralNameType::nameConstraints and referenceID is the entire encoded name
+// constraints extension value.
+//
+// The main benefit of using the exact same code paths for both is that we
+// ensure consistency between name validation and name constraint enforcement
+// regarding thing like "Which CN attributes should be considered as potential
+// CN-IDs" and "Which character sets are acceptable for CN-IDs?" If the name
+// matching and the name constraint enforcement logic were out of sync on these
+// issues (e.g. if name matching were to consider all subject CN attributes,
+// but name constraints were only enforced on the most specific subject CN),
+// trivial name constraint bypasses could result.
+
+Result
+SearchNames(/*optional*/ const Input* subjectAltName,
+            Input subject,
+            GeneralNameType referenceIDType,
+            Input referenceID,
+            FallBackToSearchWithinSubject fallBackToCommonName,
+            /*out*/ MatchResult& match)
+{
+  Result rv;
+
+  match = MatchResult::NoNamesOfGivenType;
+
+  // RFC 6125 says "A client MUST NOT seek a match for a reference identifier
+  // of CN-ID if the presented identifiers include a DNS-ID, SRV-ID, URI-ID, or
+  // any application-specific identifier types supported by the client."
+  // Accordingly, we only consider CN-IDs if there are no DNS-IDs in the
+  // subjectAltName.
+  //
+  // RFC 6125 says that IP addresses are out of scope, but for backward
+  // compatibility we accept them, by considering IP addresses to be an
+  // "application-specific identifier type supported by the client."
+  //
+  // TODO(bug XXXXXXX): Consider strengthening this check to "A client MUST NOT
+  // seek a match for a reference identifier of CN-ID if the certificate
+  // contains a subjectAltName extension."
+  //
+  // TODO(bug XXXXXXX): Consider dropping support for IP addresses as
+  // identifiers completely.
+
+  if (subjectAltName) {
+    Reader altNames;
+    rv = der::ExpectTagAndGetValueAtEnd(*subjectAltName, der::SEQUENCE,
+                                        altNames);
+    if (rv != Success) {
+      return rv;
+    }
+
+    // According to RFC 5280, "If the subjectAltName extension is present, the
+    // sequence MUST contain at least one entry." For compatibility reasons, we
+    // do not enforce this. See bug 1143085.
+    while (!altNames.AtEnd()) {
+      GeneralNameType presentedIDType;
+      Input presentedID;
+      rv = ReadGeneralName(altNames, presentedIDType, presentedID);
+      if (rv != Success) {
+        return rv;
+      }
+
+      rv = MatchPresentedIDWithReferenceID(presentedIDType, presentedID,
+                                           referenceIDType, referenceID,
+                                           match);
+      if (rv != Success) {
+        return rv;
+      }
+      if (referenceIDType != GeneralNameType::nameConstraints &&
+          match == MatchResult::Match) {
+        return Success;
+      }
+      if (presentedIDType == GeneralNameType::dNSName ||
+          presentedIDType == GeneralNameType::iPAddress) {
+        fallBackToCommonName = FallBackToSearchWithinSubject::No;
+      }
+    }
+  }
+
+  if (referenceIDType == GeneralNameType::nameConstraints) {
+    rv = CheckPresentedIDConformsToConstraints(GeneralNameType::directoryName,
+                                               subject, referenceID);
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  FallBackToSearchWithinSubject fallBackToEmailAddress;
+  if (!subjectAltName &&
+      (referenceIDType == GeneralNameType::rfc822Name ||
+       referenceIDType == GeneralNameType::nameConstraints)) {
+    fallBackToEmailAddress = FallBackToSearchWithinSubject::Yes;
+  } else {
+    fallBackToEmailAddress = FallBackToSearchWithinSubject::No;
+  }
+
+  // Short-circuit the parsing of the subject name if we're not going to match
+  // any names in it
+  if (fallBackToEmailAddress == FallBackToSearchWithinSubject::No &&
+      fallBackToCommonName == FallBackToSearchWithinSubject::No) {
+    return Success;
+  }
+
+  // Attempt to match the reference ID against the CN-ID, which we consider to
+  // be the most-specific CN AVA in the subject field.
+  //
+  // https://tools.ietf.org/html/rfc6125#section-2.3.1 says:
+  //
+  //   To reduce confusion, in this specification we avoid such terms and
+  //   instead use the terms provided under Section 1.8; in particular, we
+  //   do not use the term "(most specific) Common Name field in the subject
+  //   field" from [HTTP-TLS] and instead state that a CN-ID is a Relative
+  //   Distinguished Name (RDN) in the certificate subject containing one
+  //   and only one attribute-type-and-value pair of type Common Name (thus
+  //   removing the possibility that an RDN might contain multiple AVAs
+  //   (Attribute Value Assertions) of type CN, one of which could be
+  //   considered "most specific").
+  //
+  // https://tools.ietf.org/html/rfc6125#section-7.4 says:
+  //
+  //   [...] Although it would be preferable to
+  //   forbid multiple CN-IDs entirely, there are several reasons at this
+  //   time why this specification states that they SHOULD NOT (instead of
+  //   MUST NOT) be included [...]
+  //
+  // Consequently, it is unclear what to do when there are multiple CNs in the
+  // subject, regardless of whether there "SHOULD NOT" be.
+  //
+  // NSS's CERT_VerifyCertName mostly follows RFC2818 in this instance, which
+  // says:
+  //
+  //   If a subjectAltName extension of type dNSName is present, that MUST
+  //   be used as the identity. Otherwise, the (most specific) Common Name
+  //   field in the Subject field of the certificate MUST be used.
+  //
+  //   [...]
+  //
+  //   In some cases, the URI is specified as an IP address rather than a
+  //   hostname. In this case, the iPAddress subjectAltName must be present
+  //   in the certificate and must exactly match the IP in the URI.
+  //
+  // (The main difference from RFC2818 is that NSS's CERT_VerifyCertName also
+  // matches IP addresses in the most-specific CN.)
+  //
+  // NSS's CERT_VerifyCertName finds the most specific CN via
+  // CERT_GetCommoName, which uses CERT_GetLastNameElement. Note that many
+  // NSS-based applications, including Gecko, also use CERT_GetCommonName. It
+  // is likely that other, non-NSS-based, applications also expect only the
+  // most specific CN to be matched against the reference ID.
+  //
+  // "A Layman's Guide to a Subset of ASN.1, BER, and DER" and other sources
+  // agree that an RDNSequence is ordered from most significant (least
+  // specific) to least significant (most specific), as do other references.
+  //
+  // However, Chromium appears to use the least-specific (first) CN instead of
+  // the most-specific; see https://crbug.com/366957. Also, MSIE and some other
+  // popular implementations apparently attempt to match the reference ID
+  // against any/all CNs in the subject. Since we're trying to phase out the
+  // use of CN-IDs, we intentionally avoid trying to match MSIE's more liberal
+  // behavior.
+
+  // Name ::= CHOICE { -- only one possibility for now --
+  //   rdnSequence  RDNSequence }
+  //
+  // RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
+  //
+  // RelativeDistinguishedName ::=
+  //   SET SIZE (1..MAX) OF AttributeTypeAndValue
+  Reader subjectReader(subject);
+  return der::NestedOf(subjectReader, der::SEQUENCE, der::SET,
+                       der::EmptyAllowed::Yes, [&](Reader& r) {
+    return SearchWithinRDN(r, referenceIDType, referenceID,
+                          fallBackToEmailAddress, fallBackToCommonName, match);
+  });
+}
+
+// RelativeDistinguishedName ::=
+//   SET SIZE (1..MAX) OF AttributeTypeAndValue
+//
+// AttributeTypeAndValue ::= SEQUENCE {
+//   type     AttributeType,
+//   value    AttributeValue }
+Result
+SearchWithinRDN(Reader& rdn,
+                GeneralNameType referenceIDType,
+                Input referenceID,
+                FallBackToSearchWithinSubject fallBackToEmailAddress,
+                FallBackToSearchWithinSubject fallBackToCommonName,
+                /*in/out*/ MatchResult& match)
+{
+  do {
+    Input type;
+    uint8_t valueTag;
+    Input value;
+    Result rv = ReadAVA(rdn, type, valueTag, value);
+    if (rv != Success) {
+      return rv;
+    }
+    rv = MatchAVA(type, valueTag, value, referenceIDType, referenceID,
+                  fallBackToEmailAddress, fallBackToCommonName, match);
+    if (rv != Success) {
+      return rv;
+    }
+  } while (!rdn.AtEnd());
+
+  return Success;
+}
+
+// AttributeTypeAndValue ::= SEQUENCE {
+//   type     AttributeType,
+//   value    AttributeValue }
+//
+// AttributeType ::= OBJECT IDENTIFIER
+//
+// AttributeValue ::= ANY -- DEFINED BY AttributeType
+//
+// DirectoryString ::= CHOICE {
+//       teletexString           TeletexString (SIZE (1..MAX)),
+//       printableString         PrintableString (SIZE (1..MAX)),
+//       universalString         UniversalString (SIZE (1..MAX)),
+//       utf8String              UTF8String (SIZE (1..MAX)),
+//       bmpString               BMPString (SIZE (1..MAX)) }
+Result
+MatchAVA(Input type, uint8_t valueEncodingTag, Input presentedID,
+         GeneralNameType referenceIDType,
+         Input referenceID,
+         FallBackToSearchWithinSubject fallBackToEmailAddress,
+         FallBackToSearchWithinSubject fallBackToCommonName,
+         /*in/out*/ MatchResult& match)
+{
+  // Try to match the  CN as a DNSName or an IPAddress.
+  //
+  // id-at-commonName        AttributeType ::= { id-at 3 }
+  //
+  // -- Naming attributes of type X520CommonName:
+  // --   X520CommonName ::= DirectoryName (SIZE (1..ub-common-name))
+  // --
+  // -- Expanded to avoid parameterized type:
+  // X520CommonName ::= CHOICE {
+  //       teletexString     TeletexString   (SIZE (1..ub-common-name)),
+  //       printableString   PrintableString (SIZE (1..ub-common-name)),
+  //       universalString   UniversalString (SIZE (1..ub-common-name)),
+  //       utf8String        UTF8String      (SIZE (1..ub-common-name)),
+  //       bmpString         BMPString       (SIZE (1..ub-common-name)) }
+  //
+  // python DottedOIDToCode.py id-at-commonName 2.5.4.3
+  static const uint8_t id_at_commonName[] = {
+    0x55, 0x04, 0x03
+  };
+  if (fallBackToCommonName == FallBackToSearchWithinSubject::Yes &&
+      InputsAreEqual(type, Input(id_at_commonName))) {
+    // We might have previously found a match. Now that we've found another CN,
+    // we no longer consider that previous match to be a match, so "forget" about
+    // it.
+    match = MatchResult::NoNamesOfGivenType;
+
+    // PrintableString is a subset of ASCII that contains all the characters
+    // allowed in CN-IDs except '*'. Although '*' is illegal, there are many
+    // real-world certificates that are encoded this way, so we accept it.
+    //
+    // In the case of UTF8String, we rely on the fact that in UTF-8 the octets in
+    // a multi-byte encoding of a code point are always distinct from ASCII. Any
+    // non-ASCII byte in a UTF-8 string causes us to fail to match. We make no
+    // attempt to detect or report malformed UTF-8 (e.g. incomplete or overlong
+    // encodings of code points, or encodings of invalid code points).
+    //
+    // TeletexString is supported as long as it does not contain any escape
+    // sequences, which are not supported. We'll reject escape sequences as
+    // invalid characters in names, which means we only accept strings that are
+    // in the default character set, which is a superset of ASCII. Note that NSS
+    // actually treats TeletexString as ISO-8859-1. Many certificates that have
+    // wildcard CN-IDs (e.g. "*.example.com") use TeletexString because
+    // PrintableString is defined to not allow '*' and because, at one point in
+    // history, UTF8String was too new to use for compatibility reasons.
+    //
+    // UniversalString and BMPString are also deprecated, and they are a little
+    // harder to support because they are not single-byte ASCII superset
+    // encodings, so we don't bother.
+    if (valueEncodingTag != der::PrintableString &&
+        valueEncodingTag != der::UTF8String &&
+        valueEncodingTag != der::TeletexString) {
+      return Success;
+    }
+
+    if (IsValidPresentedDNSID(presentedID)) {
+      MatchSubjectPresentedIDWithReferenceID(GeneralNameType::dNSName,
+                                             presentedID, referenceIDType,
+                                             referenceID, match);
+    } else {
+      // We don't match CN-IDs for IPv6 addresses.
+      // MatchSubjectPresentedIDWithReferenceID ensures that it won't match an
+      // IPv4 address with an IPv6 address, so we don't need to check that
+      // referenceID is an IPv4 address here.
+      uint8_t ipv4[4];
+      if (ParseIPv4Address(presentedID, ipv4)) {
+        MatchSubjectPresentedIDWithReferenceID(GeneralNameType::iPAddress,
+                                               Input(ipv4), referenceIDType,
+                                               referenceID, match);
+      }
+    }
+
+    // Regardless of whether there was a match, we keep going in case we find
+    // another CN later. If we do find another one, then this match/mismatch
+    // will be ignored, because we only care about the most specific CN.
+
+    return Success;
+  }
+
+  // Match an email address against an emailAddress attribute in the
+  // subject.
+  //
+  // id-emailAddress      AttributeType ::= { pkcs-9 1 }
+  //
+  // EmailAddress ::=     IA5String (SIZE (1..ub-emailaddress-length))
+  //
+  // python DottedOIDToCode.py id-emailAddress 1.2.840.113549.1.9.1
+  static const uint8_t id_emailAddress[] = {
+    0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x09, 0x01
+  };
+  if (fallBackToEmailAddress == FallBackToSearchWithinSubject::Yes &&
+      InputsAreEqual(type, Input(id_emailAddress))) {
+    if (referenceIDType == GeneralNameType::rfc822Name &&
+        match == MatchResult::Match) {
+      // We already found a match; we don't need to match another one
+      return Success;
+    }
+    if (valueEncodingTag != der::IA5String) {
+      return Result::ERROR_BAD_DER;
+    }
+    return MatchPresentedIDWithReferenceID(GeneralNameType::rfc822Name,
+                                           presentedID, referenceIDType,
+                                           referenceID, match);
+  }
+
+  return Success;
+}
+
+void
+MatchSubjectPresentedIDWithReferenceID(GeneralNameType presentedIDType,
+                                       Input presentedID,
+                                       GeneralNameType referenceIDType,
+                                       Input referenceID,
+                                       /*in/out*/ MatchResult& match)
+{
+  Result rv = MatchPresentedIDWithReferenceID(presentedIDType, presentedID,
+                                              referenceIDType, referenceID,
+                                              match);
+  if (rv != Success) {
+    match = MatchResult::Mismatch;
+  }
+}
+
+Result
+MatchPresentedIDWithReferenceID(GeneralNameType presentedIDType,
+                                Input presentedID,
+                                GeneralNameType referenceIDType,
+                                Input referenceID,
+                                /*out*/ MatchResult& matchResult)
+{
+  if (referenceIDType == GeneralNameType::nameConstraints) {
+    // matchResult is irrelevant when checking name constraints; only the
+    // pass/fail result of CheckPresentedIDConformsToConstraints matters.
+    return CheckPresentedIDConformsToConstraints(presentedIDType, presentedID,
+                                                 referenceID);
+  }
+
+  if (presentedIDType != referenceIDType) {
+    matchResult = MatchResult::Mismatch;
+    return Success;
+  }
+
+  Result rv;
+  bool foundMatch;
+
+  switch (referenceIDType) {
+    case GeneralNameType::dNSName:
+      rv = MatchPresentedDNSIDWithReferenceDNSID(
+             presentedID, AllowWildcards::Yes,
+             AllowDotlessSubdomainMatches::Yes, IDRole::ReferenceID,
+             referenceID, foundMatch);
+      break;
+
+    case GeneralNameType::iPAddress:
+      foundMatch = InputsAreEqual(presentedID, referenceID);
+      rv = Success;
+      break;
+
+    case GeneralNameType::rfc822Name:
+      rv = MatchPresentedRFC822NameWithReferenceRFC822Name(
+             presentedID, IDRole::ReferenceID, referenceID, foundMatch);
+      break;
+
+    case GeneralNameType::directoryName:
+      // TODO: At some point, we may add APIs for matching DirectoryNames.
+      // fall through
+
+    case GeneralNameType::otherName: // fall through
+    case GeneralNameType::x400Address: // fall through
+    case GeneralNameType::ediPartyName: // fall through
+    case GeneralNameType::uniformResourceIdentifier: // fall through
+    case GeneralNameType::registeredID: // fall through
+    case GeneralNameType::nameConstraints:
+      return NotReached("unexpected nameType for SearchType::Match",
+                        Result::FATAL_ERROR_INVALID_ARGS);
+
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+ }
+
+  if (rv != Success) {
+    return rv;
+  }
+  matchResult = foundMatch ? MatchResult::Match : MatchResult::Mismatch;
+  return Success;
+}
+
+enum class NameConstraintsSubtrees : uint8_t
+{
+  permittedSubtrees = der::CONSTRUCTED | der::CONTEXT_SPECIFIC | 0,
+  excludedSubtrees  = der::CONSTRUCTED | der::CONTEXT_SPECIFIC | 1
+};
+
+Result CheckPresentedIDConformsToNameConstraintsSubtrees(
+         GeneralNameType presentedIDType,
+         Input presentedID,
+         Reader& nameConstraints,
+         NameConstraintsSubtrees subtreesType);
+Result MatchPresentedIPAddressWithConstraint(Input presentedID,
+                                             Input iPAddressConstraint,
+                                             /*out*/ bool& foundMatch);
+Result MatchPresentedDirectoryNameWithConstraint(
+         NameConstraintsSubtrees subtreesType, Input presentedID,
+         Input directoryNameConstraint, /*out*/ bool& matches);
+
+Result
+CheckPresentedIDConformsToConstraints(
+  GeneralNameType presentedIDType,
+  Input presentedID,
+  Input encodedNameConstraints)
+{
+  // NameConstraints ::= SEQUENCE {
+  //      permittedSubtrees       [0]     GeneralSubtrees OPTIONAL,
+  //      excludedSubtrees        [1]     GeneralSubtrees OPTIONAL }
+  Reader nameConstraints;
+  Result rv = der::ExpectTagAndGetValueAtEnd(encodedNameConstraints,
+                                             der::SEQUENCE, nameConstraints);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // RFC 5280 says "Conforming CAs MUST NOT issue certificates where name
+  // constraints is an empty sequence. That is, either the permittedSubtrees
+  // field or the excludedSubtrees MUST be present."
+  if (nameConstraints.AtEnd()) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  rv = CheckPresentedIDConformsToNameConstraintsSubtrees(
+         presentedIDType, presentedID, nameConstraints,
+         NameConstraintsSubtrees::permittedSubtrees);
+  if (rv != Success) {
+    return rv;
+  }
+
+  rv = CheckPresentedIDConformsToNameConstraintsSubtrees(
+         presentedIDType, presentedID, nameConstraints,
+         NameConstraintsSubtrees::excludedSubtrees);
+  if (rv != Success) {
+    return rv;
+  }
+
+  return der::End(nameConstraints);
+}
+
+Result
+CheckPresentedIDConformsToNameConstraintsSubtrees(
+  GeneralNameType presentedIDType,
+  Input presentedID,
+  Reader& nameConstraints,
+  NameConstraintsSubtrees subtreesType)
+{
+  if (!nameConstraints.Peek(static_cast<uint8_t>(subtreesType))) {
+    return Success;
+  }
+
+  Reader subtrees;
+  Result rv = der::ExpectTagAndGetValue(nameConstraints,
+                                        static_cast<uint8_t>(subtreesType),
+                                        subtrees);
+  if (rv != Success) {
+    return rv;
+  }
+
+  bool hasPermittedSubtreesMatch = false;
+  bool hasPermittedSubtreesMismatch = false;
+
+  // GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree
+  //
+  // do { ... } while(...) because subtrees isn't allowed to be empty.
+  do {
+    // GeneralSubtree ::= SEQUENCE {
+    //      base                    GeneralName,
+    //      minimum         [0]     BaseDistance DEFAULT 0,
+    //      maximum         [1]     BaseDistance OPTIONAL }
+    Reader subtree;
+    rv = ExpectTagAndGetValue(subtrees, der::SEQUENCE, subtree);
+    if (rv != Success) {
+      return rv;
+    }
+    GeneralNameType nameConstraintType;
+    Input base;
+    rv = ReadGeneralName(subtree, nameConstraintType, base);
+    if (rv != Success) {
+      return rv;
+    }
+    // http://tools.ietf.org/html/rfc5280#section-4.2.1.10: "Within this
+    // profile, the minimum and maximum fields are not used with any name
+    // forms, thus, the minimum MUST be zero, and maximum MUST be absent."
+    //
+    // Since the default value isn't allowed to be encoded according to the DER
+    // encoding rules for DEFAULT, this is equivalent to saying that neither
+    // minimum or maximum must be encoded.
+    rv = der::End(subtree);
+    if (rv != Success) {
+      return rv;
+    }
+
+    if (presentedIDType == nameConstraintType) {
+      bool matches;
+
+      switch (presentedIDType) {
+        case GeneralNameType::dNSName:
+          rv = MatchPresentedDNSIDWithReferenceDNSID(
+                 presentedID, AllowWildcards::Yes,
+                 AllowDotlessSubdomainMatches::Yes, IDRole::NameConstraint,
+                 base, matches);
+          if (rv != Success) {
+            return rv;
+          }
+          break;
+
+        case GeneralNameType::iPAddress:
+          rv = MatchPresentedIPAddressWithConstraint(presentedID, base,
+                                                     matches);
+          if (rv != Success) {
+            return rv;
+          }
+          break;
+
+        case GeneralNameType::directoryName:
+          rv = MatchPresentedDirectoryNameWithConstraint(subtreesType,
+                                                         presentedID, base,
+                                                         matches);
+          if (rv != Success) {
+            return rv;
+          }
+          break;
+
+        case GeneralNameType::rfc822Name:
+          rv = MatchPresentedRFC822NameWithReferenceRFC822Name(
+                 presentedID, IDRole::NameConstraint, base, matches);
+          if (rv != Success) {
+            return rv;
+          }
+          break;
+
+        // RFC 5280 says "Conforming CAs [...] SHOULD NOT impose name
+        // constraints on the x400Address, ediPartyName, or registeredID
+        // name forms. It also says "Applications conforming to this profile
+        // [...] SHOULD be able to process name constraints that are imposed
+        // on [...] uniformResourceIdentifier [...]", but we don't bother.
+        //
+        // TODO: Ask to have spec updated to say ""Conforming CAs [...] SHOULD
+        // NOT impose name constraints on the otherName, x400Address,
+        // ediPartyName, uniformResourceIdentifier, or registeredID name
+        // forms."
+        case GeneralNameType::otherName: // fall through
+        case GeneralNameType::x400Address: // fall through
+        case GeneralNameType::ediPartyName: // fall through
+        case GeneralNameType::uniformResourceIdentifier: // fall through
+        case GeneralNameType::registeredID: // fall through
+          return Result::ERROR_CERT_NOT_IN_NAME_SPACE;
+
+        case GeneralNameType::nameConstraints:
+          return NotReached("invalid presentedIDType",
+                            Result::FATAL_ERROR_LIBRARY_FAILURE);
+
+        MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+      }
+
+      switch (subtreesType) {
+        case NameConstraintsSubtrees::permittedSubtrees:
+          if (matches) {
+            hasPermittedSubtreesMatch = true;
+          } else {
+            hasPermittedSubtreesMismatch = true;
+          }
+          break;
+        case NameConstraintsSubtrees::excludedSubtrees:
+          if (matches) {
+            return Result::ERROR_CERT_NOT_IN_NAME_SPACE;
+          }
+          break;
+      }
+    }
+  } while (!subtrees.AtEnd());
+
+  if (hasPermittedSubtreesMismatch && !hasPermittedSubtreesMatch) {
+    // If there was any entry of the given type in permittedSubtrees, then it
+    // required that at least one of them must match. Since none of them did,
+    // we have a failure.
+    return Result::ERROR_CERT_NOT_IN_NAME_SPACE;
+  }
+
+  return Success;
+}
+
+// We do not distinguish between a syntactically-invalid presentedDNSID and one
+// that is syntactically valid but does not match referenceDNSID; in both
+// cases, the result is false.
+//
+// We assume that both presentedDNSID and referenceDNSID are encoded in such a
+// way that US-ASCII (7-bit) characters are encoded in one byte and no encoding
+// of a non-US-ASCII character contains a code point in the range 0-127. For
+// example, UTF-8 is OK but UTF-16 is not.
+//
+// RFC6125 says that a wildcard label may be of the form <x>*<y>.<DNSID>, where
+// <x> and/or <y> may be empty. However, NSS requires <y> to be empty, and we
+// follow NSS's stricter policy by accepting wildcards only of the form
+// <x>*.<DNSID>, where <x> may be empty.
+//
+// An relative presented DNS ID matches both an absolute reference ID and a
+// relative reference ID. Absolute presented DNS IDs are not supported:
+//
+//      Presented ID   Reference ID  Result
+//      -------------------------------------
+//      example.com    example.com   Match
+//      example.com.   example.com   Mismatch
+//      example.com    example.com.  Match
+//      example.com.   example.com.  Mismatch
+//
+// There are more subtleties documented inline in the code.
+//
+// Name constraints ///////////////////////////////////////////////////////////
+//
+// This is all RFC 5280 has to say about DNSName constraints:
+//
+//     DNS name restrictions are expressed as host.example.com.  Any DNS
+//     name that can be constructed by simply adding zero or more labels to
+//     the left-hand side of the name satisfies the name constraint.  For
+//     example, www.host.example.com would satisfy the constraint but
+//     host1.example.com would not.
+//
+// This lack of specificity has lead to a lot of uncertainty regarding
+// subdomain matching. In particular, the following questions have been
+// raised and answered:
+//
+//     Q: Does a presented identifier equal (case insensitive) to the name
+//        constraint match the constraint? For example, does the presented
+//        ID "host.example.com" match a "host.example.com" constraint?
+//     A: Yes. RFC5280 says "by simply adding zero or more labels" and this
+//        is the case of adding zero labels.
+//
+//     Q: When the name constraint does not start with ".", do subdomain
+//        presented identifiers match it? For example, does the presented
+//        ID "www.host.example.com" match a "host.example.com" constraint?
+//     A: Yes. RFC5280 says "by simply adding zero or more labels" and this
+//        is the case of adding more than zero labels. The example is the
+//        one from RFC 5280.
+//
+//     Q: When the name constraint does not start with ".", does a
+//        non-subdomain prefix match it? For example, does "bigfoo.bar.com"
+//        match "foo.bar.com"? [4]
+//     A: No. We interpret RFC 5280's language of "adding zero or more labels"
+//        to mean that whole labels must be prefixed.
+//
+//     (Note that the above three scenarios are the same as the RFC 6265
+//     domain matching rules [0].)
+//
+//     Q: Is a name constraint that starts with "." valid, and if so, what
+//        semantics does it have? For example, does a presented ID of
+//        "www.example.com" match a constraint of ".example.com"? Does a
+//        presented ID of "example.com" match a constraint of ".example.com"?
+//     A: This implementation, NSS[1], and SChannel[2] all support a
+//        leading ".", but OpenSSL[3] does not yet. Amongst the
+//        implementations that support it, a leading "." is legal and means
+//        the same thing as when the "." is omitted, EXCEPT that a
+//        presented identifier equal (case insensitive) to the name
+//        constraint is not matched; i.e. presented DNSName identifiers
+//        must be subdomains. Some CAs in Mozilla's CA program (e.g. HARICA)
+//        have name constraints with the leading "." in their root
+//        certificates. The name constraints imposed on DCISS by Mozilla also
+//        have the it, so supporting this is a requirement for backward
+//        compatibility, even if it is not yet standardized. So, for example, a
+//        presented ID of "www.example.com" matches a constraint of
+//        ".example.com" but a presented ID of "example.com" does not.
+//
+//     Q: Is there a way to prevent subdomain matches?
+//     A: Yes.
+//
+//        Some people have proposed that dNSName constraints that do not
+//        start with a "." should be restricted to exact (case insensitive)
+//        matches. However, such a change of semantics from what RFC5280
+//        specifies would be a non-backward-compatible change in the case of
+//        permittedSubtrees constraints, and it would be a security issue for
+//        excludedSubtrees constraints.
+//
+//        However, it can be done with a combination of permittedSubtrees and
+//        excludedSubtrees, e.g. "example.com" in permittedSubtrees and
+//        ".example.com" in excudedSubtrees.
+//
+//     Q: Are name constraints allowed to be specified as absolute names?
+//        For example, does a presented ID of "example.com" match a name
+//        constraint of "example.com." and vice versa.
+//     A: Absolute names are not supported as presented IDs or name
+//        constraints. Only reference IDs may be absolute.
+//
+//     Q: Is "" a valid DNSName constraints? If so, what does it mean?
+//     A: Yes. Any valid presented DNSName can be formed "by simply adding zero
+//        or more labels to the left-hand side" of "". In particular, an
+//        excludedSubtrees DNSName constraint of "" forbids all DNSNames.
+//
+//     Q: Is "." a valid DNSName constraints? If so, what does it mean?
+//     A: No, because absolute names are not allowed (see above).
+//
+// [0] RFC 6265 (Cookies) Domain Matching rules:
+//     http://tools.ietf.org/html/rfc6265#section-5.1.3
+// [1] NSS source code:
+//     https://mxr.mozilla.org/nss/source/lib/certdb/genname.c?rev=2a7348f013cb#1209
+// [2] Description of SChannel's behavior from Microsoft:
+//     http://www.imc.org/ietf-pkix/mail-archive/msg04668.html
+// [3] Proposal to add such support to OpenSSL:
+//     http://www.mail-archive.com/openssl-dev%40openssl.org/msg36204.html
+//     https://rt.openssl.org/Ticket/Display.html?id=3562
+// [4] Feedback on the lack of clarify in the definition that never got
+//     incorporated into the spec:
+//     https://www.ietf.org/mail-archive/web/pkix/current/msg21192.html
+Result
+MatchPresentedDNSIDWithReferenceDNSID(
+  Input presentedDNSID,
+  AllowWildcards allowWildcards,
+  AllowDotlessSubdomainMatches allowDotlessSubdomainMatches,
+  IDRole referenceDNSIDRole,
+  Input referenceDNSID,
+  /*out*/ bool& matches)
+{
+  if (!IsValidDNSID(presentedDNSID, IDRole::PresentedID, allowWildcards)) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  if (!IsValidDNSID(referenceDNSID, referenceDNSIDRole, AllowWildcards::No)) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  Reader presented(presentedDNSID);
+  Reader reference(referenceDNSID);
+
+  switch (referenceDNSIDRole)
+  {
+    case IDRole::ReferenceID:
+      break;
+
+    case IDRole::NameConstraint:
+    {
+      if (presentedDNSID.GetLength() > referenceDNSID.GetLength()) {
+        if (referenceDNSID.GetLength() == 0) {
+          // An empty constraint matches everything.
+          matches = true;
+          return Success;
+        }
+        // If the reference ID starts with a dot then skip the prefix of
+        // of the presented ID and start the comparison at the position of that
+        // dot. Examples:
+        //
+        //                                       Matches     Doesn't Match
+        //     -----------------------------------------------------------
+        //       original presented ID:  www.example.com    badexample.com
+        //                     skipped:  www                ba
+        //     presented ID w/o prefix:     .example.com      dexample.com
+        //                reference ID:     .example.com      .example.com
+        //
+        // If the reference ID does not start with a dot then we skip the
+        // prefix of the presented ID but also verify that the prefix ends with
+        // a dot. Examples:
+        //
+        //                                       Matches     Doesn't Match
+        //     -----------------------------------------------------------
+        //       original presented ID:  www.example.com    badexample.com
+        //                     skipped:  www                ba
+        //                 must be '.':     .                 d
+        //     presented ID w/o prefix:      example.com       example.com
+        //                reference ID:      example.com       example.com
+        //
+        if (reference.Peek('.')) {
+          if (presented.Skip(static_cast<Input::size_type>(
+                               presentedDNSID.GetLength() -
+                                 referenceDNSID.GetLength())) != Success) {
+            return NotReached("skipping subdomain failed",
+                              Result::FATAL_ERROR_LIBRARY_FAILURE);
+          }
+        } else if (allowDotlessSubdomainMatches ==
+                   AllowDotlessSubdomainMatches::Yes) {
+          if (presented.Skip(static_cast<Input::size_type>(
+                               presentedDNSID.GetLength() -
+                                 referenceDNSID.GetLength() - 1)) != Success) {
+            return NotReached("skipping subdomains failed",
+                              Result::FATAL_ERROR_LIBRARY_FAILURE);
+          }
+          uint8_t b;
+          if (presented.Read(b) != Success) {
+            return NotReached("reading from presentedDNSID failed",
+                              Result::FATAL_ERROR_LIBRARY_FAILURE);
+          }
+          if (b != '.') {
+            matches = false;
+            return Success;
+          }
+        }
+      }
+      break;
+    }
+
+    case IDRole::PresentedID: // fall through
+      return NotReached("IDRole::PresentedID is not a valid referenceDNSIDRole",
+                        Result::FATAL_ERROR_INVALID_ARGS);
+  }
+
+  // We only allow wildcard labels that consist only of '*'.
+  if (presented.Peek('*')) {
+    if (presented.Skip(1) != Success) {
+      return NotReached("Skipping '*' failed",
+                        Result::FATAL_ERROR_LIBRARY_FAILURE);
+    }
+    do {
+      // This will happen if reference is a single, relative label
+      if (reference.AtEnd()) {
+        matches = false;
+        return Success;
+      }
+      uint8_t referenceByte;
+      if (reference.Read(referenceByte) != Success) {
+        return NotReached("invalid reference ID",
+                          Result::FATAL_ERROR_INVALID_ARGS);
+      }
+    } while (!reference.Peek('.'));
+  }
+
+  for (;;) {
+    uint8_t presentedByte;
+    if (presented.Read(presentedByte) != Success) {
+      matches = false;
+      return Success;
+    }
+    uint8_t referenceByte;
+    if (reference.Read(referenceByte) != Success) {
+      matches = false;
+      return Success;
+    }
+    if (LocaleInsensitveToLower(presentedByte) !=
+        LocaleInsensitveToLower(referenceByte)) {
+      matches = false;
+      return Success;
+    }
+    if (presented.AtEnd()) {
+      // Don't allow presented IDs to be absolute.
+      if (presentedByte == '.') {
+        return Result::ERROR_BAD_DER;
+      }
+      break;
+    }
+  }
+
+  // Allow a relative presented DNS ID to match an absolute reference DNS ID,
+  // unless we're matching a name constraint.
+  if (!reference.AtEnd()) {
+    if (referenceDNSIDRole != IDRole::NameConstraint) {
+      uint8_t referenceByte;
+      if (reference.Read(referenceByte) != Success) {
+        return NotReached("read failed but not at end",
+                          Result::FATAL_ERROR_LIBRARY_FAILURE);
+      }
+      if (referenceByte != '.') {
+        matches = false;
+        return Success;
+      }
+    }
+    if (!reference.AtEnd()) {
+      matches = false;
+      return Success;
+    }
+  }
+
+  matches = true;
+  return Success;
+}
+
+// https://tools.ietf.org/html/rfc5280#section-4.2.1.10 says:
+//
+//     For IPv4 addresses, the iPAddress field of GeneralName MUST contain
+//     eight (8) octets, encoded in the style of RFC 4632 (CIDR) to represent
+//     an address range [RFC4632].  For IPv6 addresses, the iPAddress field
+//     MUST contain 32 octets similarly encoded.  For example, a name
+//     constraint for "class C" subnet 192.0.2.0 is represented as the
+//     octets C0 00 02 00 FF FF FF 00, representing the CIDR notation
+//     192.0.2.0/24 (mask 255.255.255.0).
+Result
+MatchPresentedIPAddressWithConstraint(Input presentedID,
+                                      Input iPAddressConstraint,
+                                      /*out*/ bool& foundMatch)
+{
+  if (presentedID.GetLength() != 4 && presentedID.GetLength() != 16) {
+    return Result::ERROR_BAD_DER;
+  }
+  if (iPAddressConstraint.GetLength() != 8 &&
+      iPAddressConstraint.GetLength() != 32) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  // an IPv4 address never matches an IPv6 constraint, and vice versa.
+  if (presentedID.GetLength() * 2 != iPAddressConstraint.GetLength()) {
+    foundMatch = false;
+    return Success;
+  }
+
+  Reader constraint(iPAddressConstraint);
+  Reader constraintAddress;
+  Result rv = constraint.Skip(iPAddressConstraint.GetLength() / 2u,
+                              constraintAddress);
+  if (rv != Success) {
+    return rv;
+  }
+  Reader constraintMask;
+  rv = constraint.Skip(iPAddressConstraint.GetLength() / 2u, constraintMask);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::End(constraint);
+  if (rv != Success) {
+    return rv;
+  }
+
+  Reader presented(presentedID);
+  do {
+    uint8_t presentedByte;
+    rv = presented.Read(presentedByte);
+    if (rv != Success) {
+      return rv;
+    }
+    uint8_t constraintAddressByte;
+    rv = constraintAddress.Read(constraintAddressByte);
+    if (rv != Success) {
+      return rv;
+    }
+    uint8_t constraintMaskByte;
+    rv = constraintMask.Read(constraintMaskByte);
+    if (rv != Success) {
+      return rv;
+    }
+    foundMatch =
+      ((presentedByte ^ constraintAddressByte) & constraintMaskByte) == 0;
+  } while (foundMatch && !presented.AtEnd());
+
+  return Success;
+}
+
+// AttributeTypeAndValue ::= SEQUENCE {
+//   type     AttributeType,
+//   value    AttributeValue }
+//
+// AttributeType ::= OBJECT IDENTIFIER
+//
+// AttributeValue ::= ANY -- DEFINED BY AttributeType
+Result
+ReadAVA(Reader& rdn,
+        /*out*/ Input& type,
+        /*out*/ uint8_t& valueTag,
+        /*out*/ Input& value)
+{
+  return der::Nested(rdn, der::SEQUENCE, [&](Reader& ava) -> Result {
+    Result rv = der::ExpectTagAndGetValue(ava, der::OIDTag, type);
+    if (rv != Success) {
+      return rv;
+    }
+    rv = der::ReadTagAndGetValue(ava, valueTag, value);
+    if (rv != Success) {
+      return rv;
+    }
+    return Success;
+  });
+}
+
+// Names are sequences of RDNs. RDNS are sets of AVAs. That means that RDNs are
+// unordered, so in theory we should match RDNs with equivalent AVAs that are
+// in different orders. Within the AVAs are DirectoryNames that are supposed to
+// be compared according to LDAP stringprep normalization rules (e.g.
+// normalizing whitespace), consideration of different character encodings,
+// etc. Indeed, RFC 5280 says we MUST deal with all of that.
+//
+// In practice, many implementations, including NSS, only match Names in a way
+// that only meets a subset of the requirements of RFC 5280. Those
+// normalization and character encoding conversion steps appear to be
+// unnecessary for processing real-world certificates, based on experience from
+// having used NSS in Firefox for many years.
+//
+// RFC 5280 also says "CAs issuing certificates with a restriction of the form
+// directoryName SHOULD NOT rely on implementation of the full
+// ISO DN name comparison algorithm. This implies name restrictions MUST
+// be stated identically to the encoding used in the subject field or
+// subjectAltName extension." It goes on to say, in the security
+// considerations:
+//
+//     In addition, name constraints for distinguished names MUST be stated
+//     identically to the encoding used in the subject field or
+//     subjectAltName extension.  If not, then name constraints stated as
+//     excludedSubtrees will not match and invalid paths will be accepted
+//     and name constraints expressed as permittedSubtrees will not match
+//     and valid paths will be rejected.  To avoid acceptance of invalid
+//     paths, CAs SHOULD state name constraints for distinguished names as
+//     permittedSubtrees wherever possible.
+//
+// For permittedSubtrees, the MUST-level requirement is relaxed for
+// compatibility in the case of PrintableString and UTF8String. That is, if a
+// name constraint has been encoded using UTF8String and the presented ID has
+// been encoded with a PrintableString (or vice-versa), they are considered to
+// match if they are equal everywhere except for the tag identifying the
+// encoding. See bug 1150114.
+//
+// For excludedSubtrees, we simply prohibit any non-empty directoryName
+// constraint to ensure we are not being too lenient. We support empty
+// DirectoryName constraints in excludedSubtrees so that a CA can say "Do not
+// allow any DirectoryNames in issued certificates."
+Result
+MatchPresentedDirectoryNameWithConstraint(NameConstraintsSubtrees subtreesType,
+                                          Input presentedID,
+                                          Input directoryNameConstraint,
+                                          /*out*/ bool& matches)
+{
+  Reader constraintRDNs;
+  Result rv = der::ExpectTagAndGetValueAtEnd(directoryNameConstraint,
+                                             der::SEQUENCE, constraintRDNs);
+  if (rv != Success) {
+    return rv;
+  }
+  Reader presentedRDNs;
+  rv = der::ExpectTagAndGetValueAtEnd(presentedID, der::SEQUENCE,
+                                      presentedRDNs);
+  if (rv != Success) {
+    return rv;
+  }
+
+  switch (subtreesType) {
+    case NameConstraintsSubtrees::permittedSubtrees:
+      break; // dealt with below
+    case NameConstraintsSubtrees::excludedSubtrees:
+      if (!constraintRDNs.AtEnd() || !presentedRDNs.AtEnd()) {
+        return Result::ERROR_CERT_NOT_IN_NAME_SPACE;
+      }
+      matches = true;
+      return Success;
+  }
+
+  for (;;) {
+    // The AVAs have to be fully equal, but the constraint RDNs just need to be
+    // a prefix of the presented RDNs.
+    if (constraintRDNs.AtEnd()) {
+      matches = true;
+      return Success;
+    }
+    if (presentedRDNs.AtEnd()) {
+      matches = false;
+      return Success;
+    }
+    Reader constraintRDN;
+    rv = der::ExpectTagAndGetValue(constraintRDNs, der::SET, constraintRDN);
+    if (rv != Success) {
+      return rv;
+    }
+    Reader presentedRDN;
+    rv = der::ExpectTagAndGetValue(presentedRDNs, der::SET, presentedRDN);
+    if (rv != Success) {
+      return rv;
+    }
+    while (!constraintRDN.AtEnd() && !presentedRDN.AtEnd()) {
+      Input constraintType;
+      uint8_t constraintValueTag;
+      Input constraintValue;
+      rv = ReadAVA(constraintRDN, constraintType, constraintValueTag,
+                   constraintValue);
+      if (rv != Success) {
+        return rv;
+      }
+      Input presentedType;
+      uint8_t presentedValueTag;
+      Input presentedValue;
+      rv = ReadAVA(presentedRDN, presentedType, presentedValueTag,
+                   presentedValue);
+      if (rv != Success) {
+        return rv;
+      }
+      // TODO (bug 1155767): verify that if an AVA is a PrintableString it
+      // consists only of characters valid for PrintableStrings.
+      bool avasMatch =
+        InputsAreEqual(constraintType, presentedType) &&
+        InputsAreEqual(constraintValue, presentedValue) &&
+        (constraintValueTag == presentedValueTag ||
+         (constraintValueTag == der::Tag::UTF8String &&
+          presentedValueTag == der::Tag::PrintableString) ||
+         (constraintValueTag == der::Tag::PrintableString &&
+          presentedValueTag == der::Tag::UTF8String));
+      if (!avasMatch) {
+        matches = false;
+        return Success;
+      }
+    }
+    if (!constraintRDN.AtEnd() || !presentedRDN.AtEnd()) {
+      matches = false;
+      return Success;
+    }
+  }
+}
+
+// RFC 5280 says:
+//
+//     The format of an rfc822Name is a "Mailbox" as defined in Section 4.1.2
+//     of [RFC2821]. A Mailbox has the form "Local-part@Domain".  Note that a
+//     Mailbox has no phrase (such as a common name) before it, has no comment
+//     (text surrounded in parentheses) after it, and is not surrounded by "<"
+//     and ">".  Rules for encoding Internet mail addresses that include
+//     internationalized domain names are specified in Section 7.5.
+//
+// and:
+//
+//     A name constraint for Internet mail addresses MAY specify a
+//     particular mailbox, all addresses at a particular host, or all
+//     mailboxes in a domain.  To indicate a particular mailbox, the
+//     constraint is the complete mail address.  For example,
+//     "root@example.com" indicates the root mailbox on the host
+//     "example.com".  To indicate all Internet mail addresses on a
+//     particular host, the constraint is specified as the host name.  For
+//     example, the constraint "example.com" is satisfied by any mail
+//     address at the host "example.com".  To specify any address within a
+//     domain, the constraint is specified with a leading period (as with
+//     URIs).  For example, ".example.com" indicates all the Internet mail
+//     addresses in the domain "example.com", but not Internet mail
+//     addresses on the host "example.com".
+
+bool
+IsValidRFC822Name(Input input)
+{
+  Reader reader(input);
+
+  // Local-part@.
+  bool startOfAtom = true;
+  for (;;) {
+    uint8_t presentedByte;
+    if (reader.Read(presentedByte) != Success) {
+      return false;
+    }
+    switch (presentedByte) {
+      // atext is defined in https://tools.ietf.org/html/rfc2822#section-3.2.4
+      case 'A': case 'a': case 'N': case 'n': case '0': case '!': case '#':
+      case 'B': case 'b': case 'O': case 'o': case '1': case '$': case '%':
+      case 'C': case 'c': case 'P': case 'p': case '2': case '&': case '\'':
+      case 'D': case 'd': case 'Q': case 'q': case '3': case '*': case '+':
+      case 'E': case 'e': case 'R': case 'r': case '4': case '-': case '/':
+      case 'F': case 'f': case 'S': case 's': case '5': case '=': case '?':
+      case 'G': case 'g': case 'T': case 't': case '6': case '^': case '_':
+      case 'H': case 'h': case 'U': case 'u': case '7': case '`': case '{':
+      case 'I': case 'i': case 'V': case 'v': case '8': case '|': case '}':
+      case 'J': case 'j': case 'W': case 'w': case '9': case '~':
+      case 'K': case 'k': case 'X': case 'x':
+      case 'L': case 'l': case 'Y': case 'y':
+      case 'M': case 'm': case 'Z': case 'z':
+        startOfAtom = false;
+        break;
+
+      case '.':
+        if (startOfAtom) {
+          return false;
+        }
+        startOfAtom = true;
+        break;
+
+      case '@':
+      {
+        if (startOfAtom) {
+          return false;
+        }
+        Input domain;
+        if (reader.SkipToEnd(domain) != Success) {
+          return false;
+        }
+        return IsValidDNSID(domain, IDRole::PresentedID, AllowWildcards::No);
+      }
+
+      default:
+        return false;
+    }
+  }
+}
+
+Result
+MatchPresentedRFC822NameWithReferenceRFC822Name(Input presentedRFC822Name,
+                                                IDRole referenceRFC822NameRole,
+                                                Input referenceRFC822Name,
+                                                /*out*/ bool& matches)
+{
+  if (!IsValidRFC822Name(presentedRFC822Name)) {
+    return Result::ERROR_BAD_DER;
+  }
+  Reader presented(presentedRFC822Name);
+
+  switch (referenceRFC822NameRole)
+  {
+    case IDRole::PresentedID:
+      return Result::FATAL_ERROR_INVALID_ARGS;
+
+    case IDRole::ReferenceID:
+      break;
+
+    case IDRole::NameConstraint:
+    {
+      if (InputContains(referenceRFC822Name, '@')) {
+        // The constraint is of the form "Local-part@Domain".
+        break;
+      }
+
+      // The constraint is of the form "example.com" or ".example.com".
+
+      // Skip past the '@' in the presented ID.
+      for (;;) {
+        uint8_t presentedByte;
+        if (presented.Read(presentedByte) != Success) {
+          return Result::FATAL_ERROR_LIBRARY_FAILURE;
+        }
+        if (presentedByte == '@') {
+          break;
+        }
+      }
+
+      Input presentedDNSID;
+      if (presented.SkipToEnd(presentedDNSID) != Success) {
+        return Result::FATAL_ERROR_LIBRARY_FAILURE;
+      }
+
+      return MatchPresentedDNSIDWithReferenceDNSID(
+               presentedDNSID, AllowWildcards::No,
+               AllowDotlessSubdomainMatches::No, IDRole::NameConstraint,
+               referenceRFC822Name, matches);
+    }
+  }
+
+  if (!IsValidRFC822Name(referenceRFC822Name)) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  Reader reference(referenceRFC822Name);
+
+  for (;;) {
+    uint8_t presentedByte;
+    if (presented.Read(presentedByte) != Success) {
+      matches = reference.AtEnd();
+      return Success;
+    }
+    uint8_t referenceByte;
+    if (reference.Read(referenceByte) != Success) {
+      matches = false;
+      return Success;
+    }
+    if (LocaleInsensitveToLower(presentedByte) !=
+        LocaleInsensitveToLower(referenceByte)) {
+      matches = false;
+      return Success;
+    }
+  }
+}
+
+// We avoid isdigit because it is locale-sensitive. See
+// http://pubs.opengroup.org/onlinepubs/009695399/functions/tolower.html.
+inline uint8_t
+LocaleInsensitveToLower(uint8_t a)
+{
+  if (a >= 'A' && a <= 'Z') { // unlikely
+    return static_cast<uint8_t>(
+             static_cast<uint8_t>(a - static_cast<uint8_t>('A')) +
+             static_cast<uint8_t>('a'));
+  }
+  return a;
+}
+
+bool
+StartsWithIDNALabel(Input id)
+{
+  static const uint8_t IDN_ALABEL_PREFIX[4] = { 'x', 'n', '-', '-' };
+  Reader input(id);
+  for (size_t i = 0; i < sizeof(IDN_ALABEL_PREFIX); ++i) {
+    uint8_t b;
+    if (input.Read(b) != Success) {
+      return false;
+    }
+    if (b != IDN_ALABEL_PREFIX[i]) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool
+ReadIPv4AddressComponent(Reader& input, bool lastComponent,
+                         /*out*/ uint8_t& valueOut)
+{
+  size_t length = 0;
+  unsigned int value = 0; // Must be larger than uint8_t.
+
+  for (;;) {
+    if (input.AtEnd() && lastComponent) {
+      break;
+    }
+
+    uint8_t b;
+    if (input.Read(b) != Success) {
+      return false;
+    }
+
+    if (b >= '0' && b <= '9') {
+      if (value == 0 && length > 0) {
+        return false; // Leading zeros are not allowed.
+      }
+      value = (value * 10) + (b - '0');
+      if (value > 255) {
+        return false; // Component's value is too large.
+      }
+      ++length;
+    } else if (!lastComponent && b == '.') {
+      break;
+    } else {
+      return false; // Invalid character.
+    }
+  }
+
+  if (length == 0) {
+    return false; // empty components not allowed
+  }
+
+  valueOut = static_cast<uint8_t>(value);
+  return true;
+}
+
+} // namespace
+
+// On Windows and maybe other platforms, OS-provided IP address parsing
+// functions might fail if the protocol (IPv4 or IPv6) has been disabled, so we
+// can't rely on them.
+bool
+ParseIPv4Address(Input hostname, /*out*/ uint8_t (&out)[4])
+{
+  Reader input(hostname);
+  return ReadIPv4AddressComponent(input, false, out[0]) &&
+         ReadIPv4AddressComponent(input, false, out[1]) &&
+         ReadIPv4AddressComponent(input, false, out[2]) &&
+         ReadIPv4AddressComponent(input, true, out[3]);
+}
+
+namespace {
+
+bool
+FinishIPv6Address(/*in/out*/ uint8_t (&address)[16], int numComponents,
+                  int contractionIndex)
+{
+  assert(numComponents >= 0);
+  assert(numComponents <= 8);
+  assert(contractionIndex >= -1);
+  assert(contractionIndex <= 8);
+  assert(contractionIndex <= numComponents);
+  if (!(numComponents >= 0 &&
+        numComponents <= 8 &&
+        contractionIndex >= -1 &&
+        contractionIndex <= 8 &&
+        contractionIndex <= numComponents)) {
+    return false;
+  }
+
+  if (contractionIndex == -1) {
+    // no contraction
+    return numComponents == 8;
+  }
+
+  if (numComponents >= 8) {
+    return false; // no room left to expand the contraction.
+  }
+
+  // Shift components that occur after the contraction over.
+  size_t componentsToMove = static_cast<size_t>(numComponents -
+                                                contractionIndex);
+  memmove(address + (2u * static_cast<size_t>(8 - componentsToMove)),
+          address + (2u * static_cast<size_t>(contractionIndex)),
+          componentsToMove * 2u);
+  // Fill in the contracted area with zeros.
+  std::fill_n(address + 2u * static_cast<size_t>(contractionIndex),
+              (8u - static_cast<size_t>(numComponents)) * 2u, static_cast<uint8_t>(0u));
+
+  return true;
+}
+
+} // namespace
+
+// On Windows and maybe other platforms, OS-provided IP address parsing
+// functions might fail if the protocol (IPv4 or IPv6) has been disabled, so we
+// can't rely on them.
+bool
+ParseIPv6Address(Input hostname, /*out*/ uint8_t (&out)[16])
+{
+  Reader input(hostname);
+
+  int currentComponentIndex = 0;
+  int contractionIndex = -1;
+
+  if (input.Peek(':')) {
+    // A valid input can only start with ':' if there is a contraction at the
+    // beginning.
+    uint8_t b;
+    if (input.Read(b) != Success || b != ':') {
+      assert(false);
+      return false;
+    }
+    if (input.Read(b) != Success) {
+      return false;
+    }
+    if (b != ':') {
+      return false;
+    }
+    contractionIndex = 0;
+  }
+
+  for (;;) {
+    // If we encounter a '.' then we'll have to backtrack to parse the input
+    // from startOfComponent to the end of the input as an IPv4 address.
+    Reader::Mark startOfComponent(input.GetMark());
+    uint16_t componentValue = 0;
+    size_t componentLength = 0;
+    while (!input.AtEnd() && !input.Peek(':')) {
+      uint8_t value;
+      uint8_t b;
+      if (input.Read(b) != Success) {
+        assert(false);
+        return false;
+      }
+      switch (b) {
+        case '0': case '1': case '2': case '3': case '4':
+        case '5': case '6': case '7': case '8': case '9':
+          value = static_cast<uint8_t>(b - static_cast<uint8_t>('0'));
+          break;
+        case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
+          value = static_cast<uint8_t>(b - static_cast<uint8_t>('a') +
+                                       UINT8_C(10));
+          break;
+        case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
+          value = static_cast<uint8_t>(b - static_cast<uint8_t>('A') +
+                                       UINT8_C(10));
+          break;
+        case '.':
+        {
+          // A dot indicates we hit a IPv4-syntax component. Backtrack, parsing
+          // the input from startOfComponent to the end of the input as an IPv4
+          // address, and then combine it with the other components.
+
+          if (currentComponentIndex > 6) {
+            return false; // Too many components before the IPv4 component
+          }
+
+          input.SkipToEnd();
+          Input ipv4Component;
+          if (input.GetInput(startOfComponent, ipv4Component) != Success) {
+            return false;
+          }
+          uint8_t (*ipv4)[4] =
+            reinterpret_cast<uint8_t(*)[4]>(&out[2 * currentComponentIndex]);
+          if (!ParseIPv4Address(ipv4Component, *ipv4)) {
+            return false;
+          }
+          assert(input.AtEnd());
+          currentComponentIndex += 2;
+
+          return FinishIPv6Address(out, currentComponentIndex,
+                                   contractionIndex);
+        }
+        default:
+          return false;
+      }
+      if (componentLength >= 4) {
+        // component too long
+        return false;
+      }
+      ++componentLength;
+      componentValue = (componentValue * 0x10u) + value;
+    }
+
+    if (currentComponentIndex >= 8) {
+      return false; // too many components
+    }
+
+    if (componentLength == 0) {
+      if (input.AtEnd() && currentComponentIndex == contractionIndex) {
+        if (contractionIndex == 0) {
+          // don't accept "::"
+          return false;
+        }
+        return FinishIPv6Address(out, currentComponentIndex,
+                                 contractionIndex);
+      }
+      return false;
+    }
+
+    out[2 * currentComponentIndex] =
+      static_cast<uint8_t>(componentValue / 0x100);
+    out[(2 * currentComponentIndex) + 1] =
+      static_cast<uint8_t>(componentValue % 0x100);
+
+    ++currentComponentIndex;
+
+    if (input.AtEnd()) {
+      return FinishIPv6Address(out, currentComponentIndex,
+                               contractionIndex);
+    }
+
+    uint8_t b;
+    if (input.Read(b) != Success || b != ':') {
+      assert(false);
+      return false;
+    }
+
+    if (input.Peek(':')) {
+      // Contraction
+      if (contractionIndex != -1) {
+        return false; // multiple contractions are not allowed.
+      }
+      if (input.Read(b) != Success || b != ':') {
+        assert(false);
+        return false;
+      }
+      contractionIndex = currentComponentIndex;
+      if (input.AtEnd()) {
+        // "::" at the end of the input.
+        return FinishIPv6Address(out, currentComponentIndex,
+                                 contractionIndex);
+      }
+    }
+  }
+}
+
+bool
+IsValidReferenceDNSID(Input hostname)
+{
+  return IsValidDNSID(hostname, IDRole::ReferenceID, AllowWildcards::No);
+}
+
+bool
+IsValidPresentedDNSID(Input hostname)
+{
+  return IsValidDNSID(hostname, IDRole::PresentedID, AllowWildcards::Yes);
+}
+
+namespace {
+
+// RFC 5280 Section 4.2.1.6 says that a dNSName "MUST be in the 'preferred name
+// syntax', as specified by Section 3.5 of [RFC1034] and as modified by Section
+// 2.1 of [RFC1123]" except "a dNSName of ' ' MUST NOT be used." Additionally,
+// we allow underscores for compatibility with existing practice.
+bool
+IsValidDNSID(Input hostname, IDRole idRole, AllowWildcards allowWildcards)
+{
+  if (hostname.GetLength() > 253) {
+    return false;
+  }
+
+  Reader input(hostname);
+
+  if (idRole == IDRole::NameConstraint && input.AtEnd()) {
+    return true;
+  }
+
+  size_t dotCount = 0;
+  size_t labelLength = 0;
+  bool labelIsAllNumeric = false;
+  bool labelEndsWithHyphen = false;
+
+  // Only presented IDs are allowed to have wildcard labels. And, like
+  // Chromium, be stricter than RFC 6125 requires by insisting that a
+  // wildcard label consist only of '*'.
+  bool isWildcard = allowWildcards == AllowWildcards::Yes && input.Peek('*');
+  bool isFirstByte = !isWildcard;
+  if (isWildcard) {
+    Result rv = input.Skip(1);
+    if (rv != Success) {
+      assert(false);
+      return false;
+    }
+
+    uint8_t b;
+    rv = input.Read(b);
+    if (rv != Success) {
+      return false;
+    }
+    if (b != '.') {
+      return false;
+    }
+    ++dotCount;
+  }
+
+  do {
+    static const size_t MAX_LABEL_LENGTH = 63;
+
+    uint8_t b;
+    if (input.Read(b) != Success) {
+      return false;
+    }
+    switch (b) {
+      case '-':
+        if (labelLength == 0) {
+          return false; // Labels must not start with a hyphen.
+        }
+        labelIsAllNumeric = false;
+        labelEndsWithHyphen = true;
+        ++labelLength;
+        if (labelLength > MAX_LABEL_LENGTH) {
+          return false;
+        }
+        break;
+
+      // We avoid isdigit because it is locale-sensitive. See
+      // http://pubs.opengroup.org/onlinepubs/009695399/functions/isdigit.html
+      case '0': case '5':
+      case '1': case '6':
+      case '2': case '7':
+      case '3': case '8':
+      case '4': case '9':
+        if (labelLength == 0) {
+          labelIsAllNumeric = true;
+        }
+        labelEndsWithHyphen = false;
+        ++labelLength;
+        if (labelLength > MAX_LABEL_LENGTH) {
+          return false;
+        }
+        break;
+
+      // We avoid using islower/isupper/tolower/toupper or similar things, to
+      // avoid any possibility of this code being locale-sensitive. See
+      // http://pubs.opengroup.org/onlinepubs/009695399/functions/isupper.html
+      case 'a': case 'A': case 'n': case 'N':
+      case 'b': case 'B': case 'o': case 'O':
+      case 'c': case 'C': case 'p': case 'P':
+      case 'd': case 'D': case 'q': case 'Q':
+      case 'e': case 'E': case 'r': case 'R':
+      case 'f': case 'F': case 's': case 'S':
+      case 'g': case 'G': case 't': case 'T':
+      case 'h': case 'H': case 'u': case 'U':
+      case 'i': case 'I': case 'v': case 'V':
+      case 'j': case 'J': case 'w': case 'W':
+      case 'k': case 'K': case 'x': case 'X':
+      case 'l': case 'L': case 'y': case 'Y':
+      case 'm': case 'M': case 'z': case 'Z':
+      // We allow underscores for compatibility with existing practices.
+      // See bug 1136616.
+      case '_':
+        labelIsAllNumeric = false;
+        labelEndsWithHyphen = false;
+        ++labelLength;
+        if (labelLength > MAX_LABEL_LENGTH) {
+          return false;
+        }
+        break;
+
+      case '.':
+        ++dotCount;
+        if (labelLength == 0 &&
+            (idRole != IDRole::NameConstraint || !isFirstByte)) {
+          return false;
+        }
+        if (labelEndsWithHyphen) {
+          return false; // Labels must not end with a hyphen.
+        }
+        labelLength = 0;
+        break;
+
+      default:
+        return false; // Invalid character.
+    }
+    isFirstByte = false;
+  } while (!input.AtEnd());
+
+  // Only reference IDs, not presented IDs or name constraints, may be
+  // absolute.
+  if (labelLength == 0 && idRole != IDRole::ReferenceID) {
+    return false;
+  }
+
+  if (labelEndsWithHyphen) {
+    return false; // Labels must not end with a hyphen.
+  }
+
+  if (labelIsAllNumeric) {
+    return false; // Last label must not be all numeric.
+  }
+
+  if (isWildcard) {
+    // If the DNS ID ends with a dot, the last dot signifies an absolute ID.
+    size_t labelCount = (labelLength == 0) ? dotCount : (dotCount + 1);
+
+    // Like NSS, require at least two labels to follow the wildcard label.
+    //
+    // TODO(bug XXXXXXX): Allow the TrustDomain to control this on a
+    // per-eTLD+1 basis, similar to Chromium. Even then, it might be better to
+    // still enforce that there are at least two labels after the wildcard.
+    if (labelCount < 3) {
+      return false;
+    }
+    // XXX: RFC6125 says that we shouldn't accept wildcards within an IDN
+    // A-Label. The consequence of this is that we effectively discriminate
+    // against users of languages that cannot be encoded with ASCII.
+    if (StartsWithIDNALabel(hostname)) {
+      return false;
+    }
+
+    // TODO(bug XXXXXXX): Wildcards are not allowed for EV certificates.
+    // Provide an option to indicate whether wildcards should be matched, for
+    // the purpose of helping the application enforce this.
+  }
+
+  return true;
+}
+
+} // namespace
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixnss.cpp b/security/pkix/lib/pkixnss.cpp
new file mode 100644
index 000000000..798a19265
--- /dev/null
+++ b/security/pkix/lib/pkixnss.cpp
@@ -0,0 +1,228 @@
+/*- *- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkix/pkixnss.h"
+
+#include <limits>
+
+#include "cryptohi.h"
+#include "keyhi.h"
+#include "pk11pub.h"
+#include "pkix/pkix.h"
+#include "pkixutil.h"
+#include "ScopedPtr.h"
+#include "secerr.h"
+#include "sslerr.h"
+
+namespace mozilla { namespace pkix {
+
+namespace {
+
+Result
+VerifySignedDigest(const SignedDigest& sd,
+                   Input subjectPublicKeyInfo,
+                   SECOidTag pubKeyAlg,
+                   void* pkcs11PinArg)
+{
+  SECOidTag digestAlg;
+  switch (sd.digestAlgorithm) {
+    case DigestAlgorithm::sha512: digestAlg = SEC_OID_SHA512; break;
+    case DigestAlgorithm::sha384: digestAlg = SEC_OID_SHA384; break;
+    case DigestAlgorithm::sha256: digestAlg = SEC_OID_SHA256; break;
+    case DigestAlgorithm::sha1: digestAlg = SEC_OID_SHA1; break;
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+
+  SECItem subjectPublicKeyInfoSECItem =
+    UnsafeMapInputToSECItem(subjectPublicKeyInfo);
+  ScopedPtr<CERTSubjectPublicKeyInfo, SECKEY_DestroySubjectPublicKeyInfo>
+    spki(SECKEY_DecodeDERSubjectPublicKeyInfo(&subjectPublicKeyInfoSECItem));
+  if (!spki) {
+    return MapPRErrorCodeToResult(PR_GetError());
+  }
+  ScopedPtr<SECKEYPublicKey, SECKEY_DestroyPublicKey>
+    pubKey(SECKEY_ExtractPublicKey(spki.get()));
+  if (!pubKey) {
+    return MapPRErrorCodeToResult(PR_GetError());
+  }
+
+  SECItem digestSECItem(UnsafeMapInputToSECItem(sd.digest));
+  SECItem signatureSECItem(UnsafeMapInputToSECItem(sd.signature));
+  SECStatus srv = VFY_VerifyDigestDirect(&digestSECItem, pubKey.get(),
+                                         &signatureSECItem, pubKeyAlg,
+                                         digestAlg, pkcs11PinArg);
+  if (srv != SECSuccess) {
+    return MapPRErrorCodeToResult(PR_GetError());
+  }
+
+  return Success;
+}
+
+} // namespace
+
+Result
+VerifyRSAPKCS1SignedDigestNSS(const SignedDigest& sd,
+                              Input subjectPublicKeyInfo,
+                              void* pkcs11PinArg)
+{
+  return VerifySignedDigest(sd, subjectPublicKeyInfo,
+                            SEC_OID_PKCS1_RSA_ENCRYPTION, pkcs11PinArg);
+}
+
+Result
+VerifyECDSASignedDigestNSS(const SignedDigest& sd,
+                           Input subjectPublicKeyInfo,
+                           void* pkcs11PinArg)
+{
+  return VerifySignedDigest(sd, subjectPublicKeyInfo,
+                            SEC_OID_ANSIX962_EC_PUBLIC_KEY, pkcs11PinArg);
+}
+
+Result
+DigestBufNSS(Input item,
+             DigestAlgorithm digestAlg,
+             /*out*/ uint8_t* digestBuf,
+             size_t digestBufLen)
+{
+  SECOidTag oid;
+  size_t bits;
+  switch (digestAlg) {
+    case DigestAlgorithm::sha512: oid = SEC_OID_SHA512; bits = 512; break;
+    case DigestAlgorithm::sha384: oid = SEC_OID_SHA384; bits = 384; break;
+    case DigestAlgorithm::sha256: oid = SEC_OID_SHA256; bits = 256; break;
+    case DigestAlgorithm::sha1: oid = SEC_OID_SHA1; bits = 160; break;
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+  if (digestBufLen != bits / 8) {
+    return Result::FATAL_ERROR_INVALID_ARGS;
+  }
+
+  SECItem itemSECItem = UnsafeMapInputToSECItem(item);
+  if (itemSECItem.len >
+        static_cast<decltype(itemSECItem.len)>(
+          std::numeric_limits<int32_t>::max())) {
+    PR_NOT_REACHED("large items should not be possible here");
+    return Result::FATAL_ERROR_INVALID_ARGS;
+  }
+  SECStatus srv = PK11_HashBuf(oid, digestBuf, itemSECItem.data,
+                               static_cast<int32_t>(itemSECItem.len));
+  if (srv != SECSuccess) {
+    return MapPRErrorCodeToResult(PR_GetError());
+  }
+  return Success;
+}
+
+Result
+MapPRErrorCodeToResult(PRErrorCode error)
+{
+  switch (error)
+  {
+#define MOZILLA_PKIX_MAP(mozilla_pkix_result, value, nss_result) \
+    case nss_result: return Result::mozilla_pkix_result;
+
+    MOZILLA_PKIX_MAP_LIST
+
+#undef MOZILLA_PKIX_MAP
+
+    default:
+      return Result::ERROR_UNKNOWN_ERROR;
+  }
+}
+
+PRErrorCode
+MapResultToPRErrorCode(Result result)
+{
+  switch (result)
+  {
+#define MOZILLA_PKIX_MAP(mozilla_pkix_result, value, nss_result) \
+    case Result::mozilla_pkix_result: return nss_result;
+
+    MOZILLA_PKIX_MAP_LIST
+
+#undef MOZILLA_PKIX_MAP
+
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+}
+
+void
+RegisterErrorTable()
+{
+  // Note that these error strings are not localizable.
+  // When these strings change, update the localization information too.
+  static const PRErrorMessage ErrorTableText[] = {
+    { "MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE",
+      "The server uses key pinning (HPKP) but no trusted certificate chain "
+      "could be constructed that matches the pinset. Key pinning violations "
+      "cannot be overridden." },
+    { "MOZILLA_PKIX_ERROR_CA_CERT_USED_AS_END_ENTITY",
+      "The server uses a certificate with a basic constraints extension "
+      "identifying it as a certificate authority. For a properly-issued "
+      "certificate, this should not be the case." },
+    { "MOZILLA_PKIX_ERROR_INADEQUATE_KEY_SIZE",
+      "The server presented a certificate with a key size that is too small "
+      "to establish a secure connection." },
+    { "MOZILLA_PKIX_ERROR_V1_CERT_USED_AS_CA",
+      "An X.509 version 1 certificate that is not a trust anchor was used to "
+      "issue the server's certificate. X.509 version 1 certificates are "
+      "deprecated and should not be used to sign other certificates." },
+    { "MOZILLA_PKIX_ERROR_NO_RFC822NAME_MATCH",
+      "The certificate is not valid for the given email address." },
+    { "MOZILLA_PKIX_ERROR_NOT_YET_VALID_CERTIFICATE",
+      "The server presented a certificate that is not yet valid." },
+    { "MOZILLA_PKIX_ERROR_NOT_YET_VALID_ISSUER_CERTIFICATE",
+      "A certificate that is not yet valid was used to issue the server's "
+      "certificate." },
+    { "MOZILLA_PKIX_ERROR_SIGNATURE_ALGORITHM_MISMATCH",
+      "The signature algorithm in the signature field of the certificate does "
+      "not match the algorithm in its signatureAlgorithm field." },
+    { "MOZILLA_PKIX_ERROR_OCSP_RESPONSE_FOR_CERT_MISSING",
+      "The OCSP response does not include a status for the certificate being "
+      "verified." },
+    { "MOZILLA_PKIX_ERROR_VALIDITY_TOO_LONG",
+      "The server presented a certificate that is valid for too long." },
+    { "MOZILLA_PKIX_ERROR_REQUIRED_TLS_FEATURE_MISSING",
+      "A required TLS feature is missing." },
+    { "MOZILLA_PKIX_ERROR_INVALID_INTEGER_ENCODING",
+      "The server presented a certificate that contains an invalid encoding of "
+      "an integer. Common causes include negative serial numbers, negative RSA "
+      "moduli, and encodings that are longer than necessary." },
+    { "MOZILLA_PKIX_ERROR_EMPTY_ISSUER_NAME",
+      "The server presented a certificate with an empty issuer distinguished "
+      "name." },
+  };
+  // Note that these error strings are not localizable.
+  // When these strings change, update the localization information too.
+
+  static const PRErrorTable ErrorTable = {
+    ErrorTableText,
+    "pkixerrors",
+    ERROR_BASE,
+    PR_ARRAY_SIZE(ErrorTableText)
+  };
+
+  (void) PR_ErrorInstallTable(&ErrorTable);
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixocsp.cpp b/security/pkix/lib/pkixocsp.cpp
new file mode 100644
index 000000000..06cb53bc4
--- /dev/null
+++ b/security/pkix/lib/pkixocsp.cpp
@@ -0,0 +1,1007 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <limits>
+
+#include "pkix/pkix.h"
+#include "pkixcheck.h"
+#include "pkixutil.h"
+
+namespace {
+
+const size_t SHA1_DIGEST_LENGTH = 160 / 8;
+
+} // namespace
+
+namespace mozilla { namespace pkix {
+
+// These values correspond to the tag values in the ASN.1 CertStatus
+enum class CertStatus : uint8_t {
+  Good = der::CONTEXT_SPECIFIC | 0,
+  Revoked = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 1,
+  Unknown = der::CONTEXT_SPECIFIC | 2
+};
+
+class Context final
+{
+public:
+  Context(TrustDomain& trustDomain, const CertID& certID, Time time,
+          uint16_t maxLifetimeInDays, /*optional out*/ Time* thisUpdate,
+          /*optional out*/ Time* validThrough)
+    : trustDomain(trustDomain)
+    , certID(certID)
+    , time(time)
+    , maxLifetimeInDays(maxLifetimeInDays)
+    , certStatus(CertStatus::Unknown)
+    , thisUpdate(thisUpdate)
+    , validThrough(validThrough)
+    , expired(false)
+    , matchFound(false)
+  {
+    if (thisUpdate) {
+      *thisUpdate = TimeFromElapsedSecondsAD(0);
+    }
+    if (validThrough) {
+      *validThrough = TimeFromElapsedSecondsAD(0);
+    }
+  }
+
+  TrustDomain& trustDomain;
+  const CertID& certID;
+  const Time time;
+  const uint16_t maxLifetimeInDays;
+  CertStatus certStatus;
+  Time* thisUpdate;
+  Time* validThrough;
+  bool expired;
+
+  Input signedCertificateTimestamps;
+
+  // Keep track of whether the OCSP response contains the status of the
+  // certificate we're interested in. Responders might reply without
+  // including the status of any of the requested certs, we should
+  // indicate a server failure in those cases.
+  bool matchFound;
+
+  Context(const Context&) = delete;
+  void operator=(const Context&) = delete;
+};
+
+// Verify that potentialSigner is a valid delegated OCSP response signing cert
+// according to RFC 6960 section 4.2.2.2.
+static Result
+CheckOCSPResponseSignerCert(TrustDomain& trustDomain,
+                            BackCert& potentialSigner,
+                            Input issuerSubject,
+                            Input issuerSubjectPublicKeyInfo,
+                            Time time)
+{
+  Result rv;
+
+  // We don't need to do a complete verification of the signer (i.e. we don't
+  // have to call BuildCertChain to verify the entire chain) because we
+  // already know that the issuer is valid, since revocation checking is done
+  // from the root to the parent after we've built a complete chain that we
+  // know is otherwise valid. Rather, we just need to do a one-step validation
+  // from potentialSigner to the issuer.
+  //
+  // It seems reasonable to require the KU_DIGITAL_SIGNATURE key usage on the
+  // OCSP responder certificate if the OCSP responder certificate has a
+  // key usage extension. However, according to bug 240456, some OCSP responder
+  // certificates may have only the nonRepudiation bit set. Also, the OCSP
+  // specification (RFC 6960) does not mandate any particular key usage to be
+  // asserted for OCSP responde signers. Oddly, the CABForum Baseline
+  // Requirements v.1.1.5 do say "If the Root CA Private Key is used for
+  // signing OCSP responses, then the digitalSignature bit MUST be set."
+  //
+  // Note that CheckIssuerIndependentProperties processes
+  // SEC_OID_OCSP_RESPONDER in the way that the OCSP specification requires us
+  // to--in particular, it doesn't allow SEC_OID_OCSP_RESPONDER to be implied
+  // by a missing EKU extension, unlike other EKUs.
+  //
+  // TODO(bug 926261): If we're validating for a policy then the policy OID we
+  // are validating for should be passed to CheckIssuerIndependentProperties.
+  TrustLevel unusedTrustLevel;
+  rv = CheckIssuerIndependentProperties(trustDomain, potentialSigner, time,
+                                        KeyUsage::noParticularKeyUsageRequired,
+                                        KeyPurposeId::id_kp_OCSPSigning,
+                                        CertPolicyId::anyPolicy, 0,
+                                        unusedTrustLevel);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // It is possible that there exists a certificate with the same key as the
+  // issuer but with a different name, so we need to compare names
+  // XXX(bug 926270) XXX(bug 1008133) XXX(bug 980163): Improve name
+  // comparison.
+  // TODO: needs test
+  if (!InputsAreEqual(potentialSigner.GetIssuer(), issuerSubject)) {
+    return Result::ERROR_OCSP_RESPONDER_CERT_INVALID;
+  }
+
+  // TODO(bug 926260): check name constraints
+
+  rv = VerifySignedData(trustDomain, potentialSigner.GetSignedData(),
+                        issuerSubjectPublicKeyInfo);
+
+  // TODO: check for revocation of the OCSP responder certificate unless no-check
+  // or the caller forcing no-check. To properly support the no-check policy, we'd
+  // need to enforce policy constraints from the issuerChain.
+
+  return rv;
+}
+
+enum class ResponderIDType : uint8_t
+{
+  byName = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 1,
+  byKey = der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 2
+};
+
+static inline Result OCSPResponse(Reader&, Context&);
+static inline Result ResponseBytes(Reader&, Context&);
+static inline Result BasicResponse(Reader&, Context&);
+static inline Result ResponseData(
+                       Reader& tbsResponseData,
+                       Context& context,
+                       const der::SignedDataWithSignature& signedResponseData,
+                       const DERArray& certs);
+static inline Result SingleResponse(Reader& input, Context& context);
+static Result ExtensionNotUnderstood(Reader& extnID, Input extnValue,
+                                     bool critical, /*out*/ bool& understood);
+static Result RememberSingleExtension(Context& context, Reader& extnID,
+                                      Input extnValue, bool critical,
+                                      /*out*/ bool& understood);
+static inline Result CertID(Reader& input,
+                            const Context& context,
+                            /*out*/ bool& match);
+static Result MatchKeyHash(TrustDomain& trustDomain,
+                           Input issuerKeyHash,
+                           Input issuerSubjectPublicKeyInfo,
+                           /*out*/ bool& match);
+static Result KeyHash(TrustDomain& trustDomain,
+                      Input subjectPublicKeyInfo,
+                      /*out*/ uint8_t* hashBuf, size_t hashBufSize);
+
+static Result
+MatchResponderID(TrustDomain& trustDomain,
+                 ResponderIDType responderIDType,
+                 Input responderID,
+                 Input potentialSignerSubject,
+                 Input potentialSignerSubjectPublicKeyInfo,
+                 /*out*/ bool& match)
+{
+  match = false;
+
+  switch (responderIDType) {
+    case ResponderIDType::byName:
+      // XXX(bug 926270) XXX(bug 1008133) XXX(bug 980163): Improve name
+      // comparison.
+      match = InputsAreEqual(responderID, potentialSignerSubject);
+      return Success;
+
+    case ResponderIDType::byKey:
+    {
+      Reader input(responderID);
+      Input keyHash;
+      Result rv = der::ExpectTagAndGetValue(input, der::OCTET_STRING, keyHash);
+      if (rv != Success) {
+        return rv;
+      }
+      return MatchKeyHash(trustDomain, keyHash,
+                          potentialSignerSubjectPublicKeyInfo, match);
+    }
+
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+}
+
+static Result
+VerifyOCSPSignedData(TrustDomain& trustDomain,
+                     const der::SignedDataWithSignature& signedResponseData,
+                     Input spki)
+{
+  Result rv = VerifySignedData(trustDomain, signedResponseData, spki);
+  if (rv == Result::ERROR_BAD_SIGNATURE) {
+    rv = Result::ERROR_OCSP_BAD_SIGNATURE;
+  }
+  return rv;
+}
+
+// RFC 6960 section 4.2.2.2: The OCSP responder must either be the issuer of
+// the cert or it must be a delegated OCSP response signing cert directly
+// issued by the issuer. If the OCSP responder is a delegated OCSP response
+// signer, then its certificate is (probably) embedded within the OCSP
+// response and we'll need to verify that it is a valid certificate that chains
+// *directly* to issuerCert.
+static Result
+VerifySignature(Context& context, ResponderIDType responderIDType,
+                Input responderID, const DERArray& certs,
+                const der::SignedDataWithSignature& signedResponseData)
+{
+  bool match;
+  Result rv = MatchResponderID(context.trustDomain, responderIDType,
+                               responderID, context.certID.issuer,
+                               context.certID.issuerSubjectPublicKeyInfo,
+                               match);
+  if (rv != Success) {
+    return rv;
+  }
+  if (match) {
+    return VerifyOCSPSignedData(context.trustDomain, signedResponseData,
+                                context.certID.issuerSubjectPublicKeyInfo);
+  }
+
+  size_t numCerts = certs.GetLength();
+  for (size_t i = 0; i < numCerts; ++i) {
+    BackCert cert(*certs.GetDER(i), EndEntityOrCA::MustBeEndEntity, nullptr);
+    rv = cert.Init();
+    if (rv != Success) {
+      return rv;
+    }
+    rv = MatchResponderID(context.trustDomain, responderIDType, responderID,
+                          cert.GetSubject(), cert.GetSubjectPublicKeyInfo(),
+                          match);
+    if (rv != Success) {
+      if (IsFatalError(rv)) {
+        return rv;
+      }
+      continue;
+    }
+
+    if (match) {
+      rv = CheckOCSPResponseSignerCert(context.trustDomain, cert,
+                                       context.certID.issuer,
+                                       context.certID.issuerSubjectPublicKeyInfo,
+                                       context.time);
+      if (rv != Success) {
+        if (IsFatalError(rv)) {
+          return rv;
+        }
+        continue;
+      }
+
+      return VerifyOCSPSignedData(context.trustDomain, signedResponseData,
+                                  cert.GetSubjectPublicKeyInfo());
+    }
+  }
+
+  return Result::ERROR_OCSP_INVALID_SIGNING_CERT;
+}
+
+static inline Result
+MapBadDERToMalformedOCSPResponse(Result rv)
+{
+  if (rv == Result::ERROR_BAD_DER) {
+    return Result::ERROR_OCSP_MALFORMED_RESPONSE;
+  }
+  return rv;
+}
+
+Result
+VerifyEncodedOCSPResponse(TrustDomain& trustDomain, const struct CertID& certID,
+                          Time time, uint16_t maxOCSPLifetimeInDays,
+                          Input encodedResponse,
+                          /*out*/ bool& expired,
+                          /*optional out*/ Time* thisUpdate,
+                          /*optional out*/ Time* validThrough)
+{
+  // Always initialize this to something reasonable.
+  expired = false;
+
+  Context context(trustDomain, certID, time, maxOCSPLifetimeInDays,
+                  thisUpdate, validThrough);
+
+  Reader input(encodedResponse);
+  Result rv = der::Nested(input, der::SEQUENCE, [&context](Reader& r) {
+    return OCSPResponse(r, context);
+  });
+  if (rv != Success) {
+    return MapBadDERToMalformedOCSPResponse(rv);
+  }
+  rv = der::End(input);
+  if (rv != Success) {
+    return MapBadDERToMalformedOCSPResponse(rv);
+  }
+  if (!context.matchFound) {
+    return Result::ERROR_OCSP_RESPONSE_FOR_CERT_MISSING;
+  }
+
+  expired = context.expired;
+
+  switch (context.certStatus) {
+    case CertStatus::Good:
+      if (expired) {
+        return Result::ERROR_OCSP_OLD_RESPONSE;
+      }
+      if (context.signedCertificateTimestamps.GetLength()) {
+        Input sctList;
+        rv = ExtractSignedCertificateTimestampListFromExtension(
+          context.signedCertificateTimestamps, sctList);
+        if (rv != Success) {
+          return MapBadDERToMalformedOCSPResponse(rv);
+        }
+        context.trustDomain.NoteAuxiliaryExtension(
+          AuxiliaryExtension::SCTListFromOCSPResponse, sctList);
+      }
+      return Success;
+    case CertStatus::Revoked:
+      return Result::ERROR_REVOKED_CERTIFICATE;
+    case CertStatus::Unknown:
+      return Result::ERROR_OCSP_UNKNOWN_CERT;
+     MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+}
+
+// OCSPResponse ::= SEQUENCE {
+//       responseStatus         OCSPResponseStatus,
+//       responseBytes          [0] EXPLICIT ResponseBytes OPTIONAL }
+//
+static inline Result
+OCSPResponse(Reader& input, Context& context)
+{
+  // OCSPResponseStatus ::= ENUMERATED {
+  //     successful            (0),  -- Response has valid confirmations
+  //     malformedRequest      (1),  -- Illegal confirmation request
+  //     internalError         (2),  -- Internal error in issuer
+  //     tryLater              (3),  -- Try again later
+  //                                 -- (4) is not used
+  //     sigRequired           (5),  -- Must sign the request
+  //     unauthorized          (6)   -- Request unauthorized
+  // }
+  uint8_t responseStatus;
+
+  Result rv = der::Enumerated(input, responseStatus);
+  if (rv != Success) {
+    return rv;
+  }
+  switch (responseStatus) {
+    case 0: break; // successful
+    case 1: return Result::ERROR_OCSP_MALFORMED_REQUEST;
+    case 2: return Result::ERROR_OCSP_SERVER_ERROR;
+    case 3: return Result::ERROR_OCSP_TRY_SERVER_LATER;
+    case 5: return Result::ERROR_OCSP_REQUEST_NEEDS_SIG;
+    case 6: return Result::ERROR_OCSP_UNAUTHORIZED_REQUEST;
+    default: return Result::ERROR_OCSP_UNKNOWN_RESPONSE_STATUS;
+  }
+
+  return der::Nested(input, der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 0,
+                     der::SEQUENCE, [&context](Reader& r) {
+    return ResponseBytes(r, context);
+  });
+}
+
+// ResponseBytes ::=       SEQUENCE {
+//     responseType   OBJECT IDENTIFIER,
+//     response       OCTET STRING }
+static inline Result
+ResponseBytes(Reader& input, Context& context)
+{
+  static const uint8_t id_pkix_ocsp_basic[] = {
+    0x2B, 0x06, 0x01, 0x05, 0x05, 0x07, 0x30, 0x01, 0x01
+  };
+
+  Result rv = der::OID(input, id_pkix_ocsp_basic);
+  if (rv != Success) {
+    return rv;
+  }
+
+  return der::Nested(input, der::OCTET_STRING, der::SEQUENCE,
+                     [&context](Reader& r) {
+    return BasicResponse(r, context);
+  });
+}
+
+// BasicOCSPResponse       ::= SEQUENCE {
+//    tbsResponseData      ResponseData,
+//    signatureAlgorithm   AlgorithmIdentifier,
+//    signature            BIT STRING,
+//    certs            [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL }
+Result
+BasicResponse(Reader& input, Context& context)
+{
+  Reader tbsResponseData;
+  der::SignedDataWithSignature signedData;
+  Result rv = der::SignedData(input, tbsResponseData, signedData);
+  if (rv != Success) {
+    if (rv == Result::ERROR_BAD_SIGNATURE) {
+      return Result::ERROR_OCSP_BAD_SIGNATURE;
+    }
+    return rv;
+  }
+
+  // Parse certificates, if any
+  NonOwningDERArray certs;
+  if (!input.AtEnd()) {
+    rv = der::Nested(input, der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 0,
+                     der::SEQUENCE, [&certs](Reader& certsDER) -> Result {
+      while (!certsDER.AtEnd()) {
+        Input cert;
+        Result rv = der::ExpectTagAndGetTLV(certsDER, der::SEQUENCE, cert);
+        if (rv != Success) {
+          return rv;
+        }
+        rv = certs.Append(cert);
+        if (rv != Success) {
+          return Result::ERROR_BAD_DER; // Too many certs
+        }
+      }
+      return Success;
+    });
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  return ResponseData(tbsResponseData, context, signedData, certs);
+}
+
+// ResponseData ::= SEQUENCE {
+//    version             [0] EXPLICIT Version DEFAULT v1,
+//    responderID             ResponderID,
+//    producedAt              GeneralizedTime,
+//    responses               SEQUENCE OF SingleResponse,
+//    responseExtensions  [1] EXPLICIT Extensions OPTIONAL }
+static inline Result
+ResponseData(Reader& input, Context& context,
+             const der::SignedDataWithSignature& signedResponseData,
+             const DERArray& certs)
+{
+  der::Version version;
+  Result rv = der::OptionalVersion(input, version);
+  if (rv != Success) {
+    return rv;
+  }
+  if (version != der::Version::v1) {
+    // TODO: more specific error code for bad version?
+    return Result::ERROR_BAD_DER;
+  }
+
+  // ResponderID ::= CHOICE {
+  //    byName              [1] Name,
+  //    byKey               [2] KeyHash }
+  Input responderID;
+  ResponderIDType responderIDType
+    = input.Peek(static_cast<uint8_t>(ResponderIDType::byName))
+    ? ResponderIDType::byName
+    : ResponderIDType::byKey;
+  rv = der::ExpectTagAndGetValue(input, static_cast<uint8_t>(responderIDType),
+                                 responderID);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // This is the soonest we can verify the signature. We verify the signature
+  // right away to follow the principal of minimizing the processing of data
+  // before verifying its signature.
+  rv = VerifySignature(context, responderIDType, responderID, certs,
+                       signedResponseData);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // TODO: Do we even need to parse this? Should we just skip it?
+  Time producedAt(Time::uninitialized);
+  rv = der::GeneralizedTime(input, producedAt);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // We don't accept an empty sequence of responses. In practice, a legit OCSP
+  // responder will never return an empty response, and handling the case of an
+  // empty response makes things unnecessarily complicated.
+  rv = der::NestedOf(input, der::SEQUENCE, der::SEQUENCE,
+                     der::EmptyAllowed::No, [&context](Reader& r) {
+    return SingleResponse(r, context);
+  });
+  if (rv != Success) {
+    return rv;
+  }
+
+  return der::OptionalExtensions(input,
+                                 der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 1,
+                                 ExtensionNotUnderstood);
+}
+
+// SingleResponse ::= SEQUENCE {
+//    certID                       CertID,
+//    certStatus                   CertStatus,
+//    thisUpdate                   GeneralizedTime,
+//    nextUpdate           [0]     EXPLICIT GeneralizedTime OPTIONAL,
+//    singleExtensions     [1]     EXPLICIT Extensions{{re-ocsp-crl |
+//                                              re-ocsp-archive-cutoff |
+//                                              CrlEntryExtensions, ...}
+//                                              } OPTIONAL }
+static inline Result
+SingleResponse(Reader& input, Context& context)
+{
+  bool match = false;
+  Result rv = der::Nested(input, der::SEQUENCE, [&context, &match](Reader& r) {
+    return CertID(r, context, match);
+  });
+  if (rv != Success) {
+    return rv;
+  }
+
+  if (!match) {
+    // This response does not reference the certificate we're interested in.
+    // By consuming the rest of our input and returning successfully, we can
+    // continue processing and examine another response that might have what
+    // we want.
+    input.SkipToEnd();
+    return Success;
+  }
+
+  // We found a response for the cert we're interested in.
+  context.matchFound = true;
+
+  // CertStatus ::= CHOICE {
+  //     good        [0]     IMPLICIT NULL,
+  //     revoked     [1]     IMPLICIT RevokedInfo,
+  //     unknown     [2]     IMPLICIT UnknownInfo }
+  //
+  // In the event of multiple SingleResponses for a cert that have conflicting
+  // statuses, we use the following precedence rules:
+  //
+  // * revoked overrides good and unknown
+  // * good overrides unknown
+  if (input.Peek(static_cast<uint8_t>(CertStatus::Good))) {
+    rv = der::ExpectTagAndEmptyValue(input,
+                                     static_cast<uint8_t>(CertStatus::Good));
+    if (rv != Success) {
+      return rv;
+    }
+    if (context.certStatus != CertStatus::Revoked) {
+      context.certStatus = CertStatus::Good;
+    }
+  } else if (input.Peek(static_cast<uint8_t>(CertStatus::Revoked))) {
+    // We don't need any info from the RevokedInfo structure, so we don't even
+    // parse it. TODO: We should mention issues like this in the explanation of
+    // why we treat invalid OCSP responses equivalently to revoked for OCSP
+    // stapling.
+    rv = der::ExpectTagAndSkipValue(input,
+                                    static_cast<uint8_t>(CertStatus::Revoked));
+    if (rv != Success) {
+      return rv;
+    }
+    context.certStatus = CertStatus::Revoked;
+  } else {
+    rv = der::ExpectTagAndEmptyValue(input,
+                                     static_cast<uint8_t>(CertStatus::Unknown));
+    if (rv != Success) {
+      return rv;
+    }
+  }
+
+  // http://tools.ietf.org/html/rfc6960#section-3.2
+  // 5. The time at which the status being indicated is known to be
+  //    correct (thisUpdate) is sufficiently recent;
+  // 6. When available, the time at or before which newer information will
+  //    be available about the status of the certificate (nextUpdate) is
+  //    greater than the current time.
+
+  Time thisUpdate(Time::uninitialized);
+  rv = der::GeneralizedTime(input, thisUpdate);
+  if (rv != Success) {
+    return rv;
+  }
+
+  static const uint64_t SLOP_SECONDS = Time::ONE_DAY_IN_SECONDS;
+
+  Time timePlusSlop(context.time);
+  rv = timePlusSlop.AddSeconds(SLOP_SECONDS);
+  if (rv != Success) {
+    return rv;
+  }
+  if (thisUpdate > timePlusSlop) {
+    return Result::ERROR_OCSP_FUTURE_RESPONSE;
+  }
+
+  Time notAfter(Time::uninitialized);
+  static const uint8_t NEXT_UPDATE_TAG =
+    der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 0;
+  if (input.Peek(NEXT_UPDATE_TAG)) {
+    Time nextUpdate(Time::uninitialized);
+    rv = der::Nested(input, NEXT_UPDATE_TAG, [&nextUpdate](Reader& r) {
+      return der::GeneralizedTime(r, nextUpdate);
+    });
+    if (rv != Success) {
+      return rv;
+    }
+
+    if (nextUpdate < thisUpdate) {
+      return Result::ERROR_OCSP_MALFORMED_RESPONSE;
+    }
+    notAfter = thisUpdate;
+    if (notAfter.AddSeconds(context.maxLifetimeInDays *
+                            Time::ONE_DAY_IN_SECONDS) != Success) {
+      // This could only happen if we're dealing with times beyond the year
+      // 10,000AD.
+      return Result::ERROR_OCSP_FUTURE_RESPONSE;
+    }
+    if (nextUpdate <= notAfter) {
+      notAfter = nextUpdate;
+    }
+  } else {
+    // NSS requires all OCSP responses without a nextUpdate to be recent.
+    // Match that stricter behavior.
+    notAfter = thisUpdate;
+    if (notAfter.AddSeconds(Time::ONE_DAY_IN_SECONDS) != Success) {
+      // This could only happen if we're dealing with times beyond the year
+      // 10,000AD.
+      return Result::ERROR_OCSP_FUTURE_RESPONSE;
+    }
+  }
+
+  // Add some slop to hopefully handle clock-skew.
+  Time notAfterPlusSlop(notAfter);
+  rv = notAfterPlusSlop.AddSeconds(SLOP_SECONDS);
+  if (rv != Success) {
+    // This could only happen if we're dealing with times beyond the year
+    // 10,000AD.
+    return Result::ERROR_OCSP_FUTURE_RESPONSE;
+  }
+  if (context.time > notAfterPlusSlop) {
+    context.expired = true;
+  }
+
+  rv = der::OptionalExtensions(
+    input,
+    der::CONTEXT_SPECIFIC | der::CONSTRUCTED | 1,
+    [&context](Reader& extnID, const Input& extnValue, bool critical,
+               /*out*/ bool& understood) {
+      return RememberSingleExtension(context, extnID, extnValue, critical,
+                                     understood);
+    });
+
+  if (rv != Success) {
+    return rv;
+  }
+
+  if (context.thisUpdate) {
+    *context.thisUpdate = thisUpdate;
+  }
+  if (context.validThrough) {
+    *context.validThrough = notAfterPlusSlop;
+  }
+
+  return Success;
+}
+
+// CertID          ::=     SEQUENCE {
+//        hashAlgorithm       AlgorithmIdentifier,
+//        issuerNameHash      OCTET STRING, -- Hash of issuer's DN
+//        issuerKeyHash       OCTET STRING, -- Hash of issuer's public key
+//        serialNumber        CertificateSerialNumber }
+static inline Result
+CertID(Reader& input, const Context& context, /*out*/ bool& match)
+{
+  match = false;
+
+  DigestAlgorithm hashAlgorithm;
+  Result rv = der::DigestAlgorithmIdentifier(input, hashAlgorithm);
+  if (rv != Success) {
+    if (rv == Result::ERROR_INVALID_ALGORITHM) {
+      // Skip entries that are hashed with algorithms we don't support.
+      input.SkipToEnd();
+      return Success;
+    }
+    return rv;
+  }
+
+  Input issuerNameHash;
+  rv = der::ExpectTagAndGetValue(input, der::OCTET_STRING, issuerNameHash);
+  if (rv != Success) {
+    return rv;
+  }
+
+  Input issuerKeyHash;
+  rv = der::ExpectTagAndGetValue(input, der::OCTET_STRING, issuerKeyHash);
+  if (rv != Success) {
+    return rv;
+  }
+
+  Input serialNumber;
+  rv = der::CertificateSerialNumber(input, serialNumber);
+  if (rv != Success) {
+    return rv;
+  }
+
+  if (!InputsAreEqual(serialNumber, context.certID.serialNumber)) {
+    // This does not reference the certificate we're interested in.
+    // Consume the rest of the input and return successfully to
+    // potentially continue processing other responses.
+    input.SkipToEnd();
+    return Success;
+  }
+
+  // TODO: support SHA-2 hashes.
+
+  if (hashAlgorithm != DigestAlgorithm::sha1) {
+    // Again, not interested in this response. Consume input, return success.
+    input.SkipToEnd();
+    return Success;
+  }
+
+  if (issuerNameHash.GetLength() != SHA1_DIGEST_LENGTH) {
+    return Result::ERROR_OCSP_MALFORMED_RESPONSE;
+  }
+
+  // From http://tools.ietf.org/html/rfc6960#section-4.1.1:
+  // "The hash shall be calculated over the DER encoding of the
+  // issuer's name field in the certificate being checked."
+  uint8_t hashBuf[SHA1_DIGEST_LENGTH];
+  rv = context.trustDomain.DigestBuf(context.certID.issuer,
+                                     DigestAlgorithm::sha1, hashBuf,
+                                     sizeof(hashBuf));
+  if (rv != Success) {
+    return rv;
+  }
+  Input computed(hashBuf);
+  if (!InputsAreEqual(computed, issuerNameHash)) {
+    // Again, not interested in this response. Consume input, return success.
+    input.SkipToEnd();
+    return Success;
+  }
+
+  return MatchKeyHash(context.trustDomain, issuerKeyHash,
+                      context.certID.issuerSubjectPublicKeyInfo, match);
+}
+
+// From http://tools.ietf.org/html/rfc6960#section-4.1.1:
+// "The hash shall be calculated over the value (excluding tag and length) of
+// the subject public key field in the issuer's certificate."
+//
+// From http://tools.ietf.org/html/rfc6960#appendix-B.1:
+// KeyHash ::= OCTET STRING -- SHA-1 hash of responder's public key
+//                          -- (i.e., the SHA-1 hash of the value of the
+//                          -- BIT STRING subjectPublicKey [excluding
+//                          -- the tag, length, and number of unused
+//                          -- bits] in the responder's certificate)
+static Result
+MatchKeyHash(TrustDomain& trustDomain, Input keyHash,
+             const Input subjectPublicKeyInfo, /*out*/ bool& match)
+{
+  if (keyHash.GetLength() != SHA1_DIGEST_LENGTH)  {
+    return Result::ERROR_OCSP_MALFORMED_RESPONSE;
+  }
+  uint8_t hashBuf[SHA1_DIGEST_LENGTH];
+  Result rv = KeyHash(trustDomain, subjectPublicKeyInfo, hashBuf,
+                      sizeof hashBuf);
+  if (rv != Success) {
+    return rv;
+  }
+  Input computed(hashBuf);
+  match = InputsAreEqual(computed, keyHash);
+  return Success;
+}
+
+// TODO(bug 966856): support SHA-2 hashes
+Result
+KeyHash(TrustDomain& trustDomain, const Input subjectPublicKeyInfo,
+        /*out*/ uint8_t* hashBuf, size_t hashBufSize)
+{
+  if (!hashBuf || hashBufSize != SHA1_DIGEST_LENGTH) {
+    return Result::FATAL_ERROR_LIBRARY_FAILURE;
+  }
+
+  // RFC 5280 Section 4.1
+  //
+  // SubjectPublicKeyInfo  ::=  SEQUENCE  {
+  //    algorithm            AlgorithmIdentifier,
+  //    subjectPublicKey     BIT STRING  }
+
+  Reader spki;
+  Result rv = der::ExpectTagAndGetValueAtEnd(subjectPublicKeyInfo,
+                                             der::SEQUENCE, spki);
+  if (rv != Success) {
+    return rv;
+  }
+
+  // Skip AlgorithmIdentifier
+  rv = der::ExpectTagAndSkipValue(spki, der::SEQUENCE);
+  if (rv != Success) {
+    return rv;
+  }
+
+  Input subjectPublicKey;
+  rv = der::BitStringWithNoUnusedBits(spki, subjectPublicKey);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = der::End(spki);
+  if (rv != Success) {
+    return rv;
+  }
+
+  return trustDomain.DigestBuf(subjectPublicKey, DigestAlgorithm::sha1,
+                               hashBuf, hashBufSize);
+}
+
+Result
+ExtensionNotUnderstood(Reader& /*extnID*/, Input /*extnValue*/,
+                       bool /*critical*/, /*out*/ bool& understood)
+{
+  understood = false;
+  return Success;
+}
+
+Result
+RememberSingleExtension(Context& context, Reader& extnID, Input extnValue,
+                        bool /*critical*/, /*out*/ bool& understood)
+{
+  understood = false;
+
+  // SingleExtension for Signed Certificate Timestamp List.
+  // See Section 3.3 of RFC 6962.
+  // python DottedOIDToCode.py
+  //   id_ocsp_singleExtensionSctList 1.3.6.1.4.1.11129.2.4.5
+  static const uint8_t id_ocsp_singleExtensionSctList[] = {
+    0x2b, 0x06, 0x01, 0x04, 0x01, 0xd6, 0x79, 0x02, 0x04, 0x05
+  };
+
+  if (extnID.MatchRest(id_ocsp_singleExtensionSctList)) {
+    // Empty values are not allowed for this extension. Note that
+    // we assume this later, when checking if the extension was present.
+    if (extnValue.GetLength() == 0) {
+      return Result::ERROR_EXTENSION_VALUE_INVALID;
+    }
+    if (context.signedCertificateTimestamps.Init(extnValue) != Success) {
+      // Duplicate extension.
+      return Result::ERROR_EXTENSION_VALUE_INVALID;
+    }
+    understood = true;
+  }
+
+  return Success;
+}
+
+//   1. The certificate identified in a received response corresponds to
+//      the certificate that was identified in the corresponding request;
+//   2. The signature on the response is valid;
+//   3. The identity of the signer matches the intended recipient of the
+//      request;
+//   4. The signer is currently authorized to provide a response for the
+//      certificate in question;
+//   5. The time at which the status being indicated is known to be
+//      correct (thisUpdate) is sufficiently recent;
+//   6. When available, the time at or before which newer information will
+//      be available about the status of the certificate (nextUpdate) is
+//      greater than the current time.
+//
+//   Responses whose nextUpdate value is earlier than
+//   the local system time value SHOULD be considered unreliable.
+//   Responses whose thisUpdate time is later than the local system time
+//   SHOULD be considered unreliable.
+//
+//   If nextUpdate is not set, the responder is indicating that newer
+//   revocation information is available all the time.
+//
+// http://tools.ietf.org/html/rfc5019#section-4
+
+Result
+CreateEncodedOCSPRequest(TrustDomain& trustDomain, const struct CertID& certID,
+                         /*out*/ uint8_t (&out)[OCSP_REQUEST_MAX_LENGTH],
+                         /*out*/ size_t& outLen)
+{
+  // We do not add any extensions to the request.
+
+  // RFC 6960 says "An OCSP client MAY wish to specify the kinds of response
+  // types it understands. To do so, it SHOULD use an extension with the OID
+  // id-pkix-ocsp-response." This use of MAY and SHOULD is unclear. MSIE11
+  // on Windows 8.1 does not include any extensions, whereas NSS has always
+  // included the id-pkix-ocsp-response extension. Avoiding the sending the
+  // extension is better for OCSP GET because it makes the request smaller,
+  // and thus more likely to fit within the 255 byte limit for OCSP GET that
+  // is specified in RFC 5019 Section 5.
+
+  // Bug 966856: Add the id-pkix-ocsp-pref-sig-algs extension.
+
+  // Since we don't know whether the OCSP responder supports anything other
+  // than SHA-1, we have no choice but to use SHA-1 for issuerNameHash and
+  // issuerKeyHash.
+  static const uint8_t hashAlgorithm[11] = {
+    0x30, 0x09,                               // SEQUENCE
+    0x06, 0x05, 0x2B, 0x0E, 0x03, 0x02, 0x1A, //   OBJECT IDENTIFIER id-sha1
+    0x05, 0x00,                               //   NULL
+  };
+  static const uint8_t hashLen = 160 / 8;
+
+  static const unsigned int totalLenWithoutSerialNumberData
+    = 2                             // OCSPRequest
+    + 2                             //   tbsRequest
+    + 2                             //     requestList
+    + 2                             //       Request
+    + 2                             //         reqCert (CertID)
+    + sizeof(hashAlgorithm)         //           hashAlgorithm
+    + 2 + hashLen                   //           issuerNameHash
+    + 2 + hashLen                   //           issuerKeyHash
+    + 2;                            //           serialNumber (header)
+
+  // The only way we could have a request this large is if the serialNumber was
+  // ridiculously and unreasonably large. RFC 5280 says "Conforming CAs MUST
+  // NOT use serialNumber values longer than 20 octets." With this restriction,
+  // we allow for some amount of non-conformance with that requirement while
+  // still ensuring we can encode the length values in the ASN.1 TLV structures
+  // in a single byte.
+  static_assert(totalLenWithoutSerialNumberData < OCSP_REQUEST_MAX_LENGTH,
+                "totalLenWithoutSerialNumberData too big");
+  if (certID.serialNumber.GetLength() >
+        OCSP_REQUEST_MAX_LENGTH - totalLenWithoutSerialNumberData) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  outLen = totalLenWithoutSerialNumberData + certID.serialNumber.GetLength();
+
+  uint8_t totalLen = static_cast<uint8_t>(outLen);
+
+  uint8_t* d = out;
+  *d++ = 0x30; *d++ = totalLen - 2u;  // OCSPRequest (SEQUENCE)
+  *d++ = 0x30; *d++ = totalLen - 4u;  //   tbsRequest (SEQUENCE)
+  *d++ = 0x30; *d++ = totalLen - 6u;  //     requestList (SEQUENCE OF)
+  *d++ = 0x30; *d++ = totalLen - 8u;  //       Request (SEQUENCE)
+  *d++ = 0x30; *d++ = totalLen - 10u; //         reqCert (CertID SEQUENCE)
+
+  // reqCert.hashAlgorithm
+  for (size_t i = 0; i < sizeof(hashAlgorithm); ++i) {
+    *d++ = hashAlgorithm[i];
+  }
+
+  // reqCert.issuerNameHash (OCTET STRING)
+  *d++ = 0x04;
+  *d++ = hashLen;
+  Result rv = trustDomain.DigestBuf(certID.issuer, DigestAlgorithm::sha1, d,
+                                    hashLen);
+  if (rv != Success) {
+    return rv;
+  }
+  d += hashLen;
+
+  // reqCert.issuerKeyHash (OCTET STRING)
+  *d++ = 0x04;
+  *d++ = hashLen;
+  rv = KeyHash(trustDomain, certID.issuerSubjectPublicKeyInfo, d, hashLen);
+  if (rv != Success) {
+    return rv;
+  }
+  d += hashLen;
+
+  // reqCert.serialNumber (INTEGER)
+  *d++ = 0x02; // INTEGER
+  *d++ = static_cast<uint8_t>(certID.serialNumber.GetLength());
+  Reader serialNumber(certID.serialNumber);
+  do {
+    rv = serialNumber.Read(*d);
+    if (rv != Success) {
+      return rv;
+    }
+    ++d;
+  } while (!serialNumber.AtEnd());
+
+  assert(d == out + totalLen);
+
+  return Success;
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixresult.cpp b/security/pkix/lib/pkixresult.cpp
new file mode 100644
index 000000000..670642de8
--- /dev/null
+++ b/security/pkix/lib/pkixresult.cpp
@@ -0,0 +1,46 @@
+/*- *- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkix/Result.h"
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix {
+
+const char*
+MapResultToName(Result result)
+{
+  switch (result)
+  {
+#define MOZILLA_PKIX_MAP(mozilla_pkix_result, value, nss_result) \
+    case Result::mozilla_pkix_result: return "Result::" #mozilla_pkix_result;
+
+    MOZILLA_PKIX_MAP_LIST
+
+#undef MOZILLA_PKIX_MAP
+
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixtime.cpp b/security/pkix/lib/pkixtime.cpp
new file mode 100644
index 000000000..ace23dd41
--- /dev/null
+++ b/security/pkix/lib/pkixtime.cpp
@@ -0,0 +1,78 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2014 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkix/Time.h"
+#include "pkixutil.h"
+
+#ifdef WIN32
+#ifdef _MSC_VER
+#pragma warning(push, 3)
+#endif
+#include "windows.h"
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+#else
+#include "sys/time.h"
+#endif
+
+namespace mozilla { namespace pkix {
+
+Time
+Now()
+{
+  uint64_t seconds;
+
+#ifdef WIN32
+  // "Contains a 64-bit value representing the number of 100-nanosecond
+  // intervals since January 1, 1601 (UTC)."
+  //   - http://msdn.microsoft.com/en-us/library/windows/desktop/ms724284(v=vs.85).aspx
+  FILETIME ft;
+  GetSystemTimeAsFileTime(&ft);
+  uint64_t ft64 = (static_cast<uint64_t>(ft.dwHighDateTime) << 32) |
+                  ft.dwLowDateTime;
+  seconds = (DaysBeforeYear(1601) * Time::ONE_DAY_IN_SECONDS) +
+            ft64 / (1000u * 1000u * 1000u / 100u);
+#else
+  // "The gettimeofday() function shall obtain the current time, expressed as
+  // seconds and microseconds since the Epoch."
+  //   - http://pubs.opengroup.org/onlinepubs/009695399/functions/gettimeofday.html
+  timeval tv;
+  (void) gettimeofday(&tv, nullptr);
+  seconds = (DaysBeforeYear(1970) * Time::ONE_DAY_IN_SECONDS) +
+            static_cast<uint64_t>(tv.tv_sec);
+#endif
+
+  return TimeFromElapsedSecondsAD(seconds);
+}
+
+Time
+TimeFromEpochInSeconds(uint64_t secondsSinceEpoch)
+{
+  uint64_t seconds = (DaysBeforeYear(1970) * Time::ONE_DAY_IN_SECONDS) +
+                     secondsSinceEpoch;
+  return TimeFromElapsedSecondsAD(seconds);
+}
+
+} } // namespace mozilla::pkix
diff --git a/security/pkix/lib/pkixutil.h b/security/pkix/lib/pkixutil.h
new file mode 100644
index 000000000..31557ea81
--- /dev/null
+++ b/security/pkix/lib/pkixutil.h
@@ -0,0 +1,289 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2013 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef mozilla_pkix_pkixutil_h
+#define mozilla_pkix_pkixutil_h
+
+#include "pkixder.h"
+
+namespace mozilla { namespace pkix {
+
+// During path building and verification, we build a linked list of BackCerts
+// from the current cert toward the end-entity certificate. The linked list
+// is used to verify properties that aren't local to the current certificate
+// and/or the direct link between the current certificate and its issuer,
+// such as name constraints.
+//
+// Each BackCert contains pointers to all the given certificate's extensions
+// so that we can parse the extension block once and then process the
+// extensions in an order that may be different than they appear in the cert.
+class BackCert final
+{
+public:
+  // certDER and childCert must be valid for the lifetime of BackCert.
+  BackCert(Input certDER, EndEntityOrCA endEntityOrCA,
+           const BackCert* childCert)
+    : der(certDER)
+    , endEntityOrCA(endEntityOrCA)
+    , childCert(childCert)
+  {
+  }
+
+  Result Init();
+
+  const Input GetDER() const { return der; }
+  const der::SignedDataWithSignature& GetSignedData() const {
+    return signedData;
+  }
+
+  der::Version GetVersion() const { return version; }
+  const Input GetSerialNumber() const { return serialNumber; }
+  const Input GetSignature() const { return signature; }
+  const Input GetIssuer() const { return issuer; }
+  // XXX: "validity" is a horrible name for the structure that holds
+  // notBefore & notAfter, but that is the name used in RFC 5280 and we use the
+  // RFC 5280 names for everything.
+  const Input GetValidity() const { return validity; }
+  const Input GetSubject() const { return subject; }
+  const Input GetSubjectPublicKeyInfo() const
+  {
+    return subjectPublicKeyInfo;
+  }
+  const Input* GetAuthorityInfoAccess() const
+  {
+    return MaybeInput(authorityInfoAccess);
+  }
+  const Input* GetBasicConstraints() const
+  {
+    return MaybeInput(basicConstraints);
+  }
+  const Input* GetCertificatePolicies() const
+  {
+    return MaybeInput(certificatePolicies);
+  }
+  const Input* GetExtKeyUsage() const
+  {
+    return MaybeInput(extKeyUsage);
+  }
+  const Input* GetKeyUsage() const
+  {
+    return MaybeInput(keyUsage);
+  }
+  const Input* GetInhibitAnyPolicy() const
+  {
+    return MaybeInput(inhibitAnyPolicy);
+  }
+  const Input* GetNameConstraints() const
+  {
+    return MaybeInput(nameConstraints);
+  }
+  const Input* GetSubjectAltName() const
+  {
+    return MaybeInput(subjectAltName);
+  }
+  const Input* GetRequiredTLSFeatures() const
+  {
+    return MaybeInput(requiredTLSFeatures);
+  }
+  const Input* GetSignedCertificateTimestamps() const
+  {
+    return MaybeInput(signedCertificateTimestamps);
+  }
+
+private:
+  const Input der;
+
+public:
+  const EndEntityOrCA endEntityOrCA;
+  BackCert const* const childCert;
+
+private:
+  // When parsing certificates in BackCert::Init, we don't accept empty
+  // extensions. Consequently, we don't have to store a distinction between
+  // empty extensions and extensions that weren't included. However, when
+  // *processing* extensions, we distinguish between whether an extension was
+  // included or not based on whetehr the GetXXX function for the extension
+  // returns nullptr.
+  static inline const Input* MaybeInput(const Input& item)
+  {
+    return item.GetLength() > 0 ? &item : nullptr;
+  }
+
+  der::SignedDataWithSignature signedData;
+
+  der::Version version;
+  Input serialNumber;
+  Input signature;
+  Input issuer;
+  // XXX: "validity" is a horrible name for the structure that holds
+  // notBefore & notAfter, but that is the name used in RFC 5280 and we use the
+  // RFC 5280 names for everything.
+  Input validity;
+  Input subject;
+  Input subjectPublicKeyInfo;
+
+  Input authorityInfoAccess;
+  Input basicConstraints;
+  Input certificatePolicies;
+  Input extKeyUsage;
+  Input inhibitAnyPolicy;
+  Input keyUsage;
+  Input nameConstraints;
+  Input subjectAltName;
+  Input criticalNetscapeCertificateType;
+  Input requiredTLSFeatures;
+  Input signedCertificateTimestamps; // RFC 6962 (Certificate Transparency)
+
+  Result RememberExtension(Reader& extnID, Input extnValue, bool critical,
+                           /*out*/ bool& understood);
+
+  BackCert(const BackCert&) = delete;
+  void operator=(const BackCert&) = delete;
+};
+
+class NonOwningDERArray final : public DERArray
+{
+public:
+  NonOwningDERArray()
+    : numItems(0)
+  {
+    // we don't need to initialize the items array because we always check
+    // numItems before accessing i.
+  }
+
+  size_t GetLength() const override { return numItems; }
+
+  const Input* GetDER(size_t i) const override
+  {
+    return i < numItems ? &items[i] : nullptr;
+  }
+
+  Result Append(Input der)
+  {
+    if (numItems >= MAX_LENGTH) {
+      return Result::FATAL_ERROR_INVALID_ARGS;
+    }
+    Result rv = items[numItems].Init(der); // structure assignment
+    if (rv != Success) {
+      return rv;
+    }
+    ++numItems;
+    return Success;
+  }
+
+  // Public so we can static_assert on this. Keep in sync with MAX_SUBCA_COUNT.
+  static const size_t MAX_LENGTH = 8;
+private:
+  Input items[MAX_LENGTH]; // avoids any heap allocations
+  size_t numItems;
+
+  NonOwningDERArray(const NonOwningDERArray&) = delete;
+  void operator=(const NonOwningDERArray&) = delete;
+};
+
+// Extracts the SignedCertificateTimestampList structure which is encoded as an
+// OCTET STRING within the X.509v3 / OCSP extensions (see RFC 6962 section 3.3).
+Result
+ExtractSignedCertificateTimestampListFromExtension(Input extnValue,
+                                                   Input& sctList);
+
+inline unsigned int
+DaysBeforeYear(unsigned int year)
+{
+  assert(year <= 9999);
+  return ((year - 1u) * 365u)
+       + ((year - 1u) / 4u)    // leap years are every 4 years,
+       - ((year - 1u) / 100u)  // except years divisible by 100,
+       + ((year - 1u) / 400u); // except years divisible by 400.
+}
+
+static const size_t MAX_DIGEST_SIZE_IN_BYTES = 512 / 8; // sha-512
+
+Result DigestSignedData(TrustDomain& trustDomain,
+                        const der::SignedDataWithSignature& signedData,
+                        /*out*/ uint8_t(&digestBuf)[MAX_DIGEST_SIZE_IN_BYTES],
+                        /*out*/ der::PublicKeyAlgorithm& publicKeyAlg,
+                        /*out*/ SignedDigest& signedDigest);
+
+Result VerifySignedDigest(TrustDomain& trustDomain,
+                          der::PublicKeyAlgorithm publicKeyAlg,
+                          const SignedDigest& signedDigest,
+                          Input signerSubjectPublicKeyInfo);
+
+// Combines DigestSignedData and VerifySignedDigest
+Result VerifySignedData(TrustDomain& trustDomain,
+                        const der::SignedDataWithSignature& signedData,
+                        Input signerSubjectPublicKeyInfo);
+
+// Extracts the key parameters from |subjectPublicKeyInfo|, invoking
+// the relevant methods of |trustDomain|.
+Result
+CheckSubjectPublicKeyInfo(Input subjectPublicKeyInfo, TrustDomain& trustDomain,
+                          EndEntityOrCA endEntityOrCA);
+
+// In a switch over an enum, sometimes some compilers are not satisfied that
+// all control flow paths have been considered unless there is a default case.
+// However, in our code, such a default case is almost always unreachable dead
+// code. That can be particularly problematic when the compiler wants the code
+// to choose a value, such as a return value, for the default case, but there's
+// no appropriate "impossible case" value to choose.
+//
+// MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM accounts for this. Example:
+//
+//     // In xy.cpp
+//     #include "xt.h"
+//
+//     enum class XY { X, Y };
+//
+//     int func(XY xy) {
+//       switch (xy) {
+//         case XY::X: return 1;
+//         case XY::Y; return 2;
+//         MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+//       }
+//     }
+#if defined(__clang__)
+// Clang will warn if not all cases are covered (-Wswitch-enum) AND it will
+// warn if a switch statement that covers every enum label has a default case
+// (-W-covered-switch-default). Versions prior to 3.5 warned about unreachable
+// code in such default cases (-Wunreachable-code) even when
+// -W-covered-switch-default was disabled, but that changed in Clang 3.5.
+#define MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM // empty
+#elif defined(__GNUC__)
+// GCC will warn if not all cases are covered (-Wswitch-enum). It does not
+// assume that the default case is unreachable.
+#define MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM \
+        default: assert(false); __builtin_unreachable();
+#elif defined(_MSC_VER)
+// MSVC will warn if not all cases are covered (C4061, level 4). It does not
+// assume that the default case is unreachable.
+#define MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM \
+        default: assert(false); __assume(0);
+#else
+#error Unsupported compiler for MOZILLA_PKIX_UNREACHABLE_DEFAULT.
+#endif
+
+} } // namespace mozilla::pkix
+
+#endif // mozilla_pkix_pkixutil_h
diff --git a/security/pkix/lib/pkixverify.cpp b/security/pkix/lib/pkixverify.cpp
new file mode 100644
index 000000000..16737e49d
--- /dev/null
+++ b/security/pkix/lib/pkixverify.cpp
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This code is made available to you under your choice of the following sets
+ * of licensing terms:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* Copyright 2015 Mozilla Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "pkixutil.h"
+
+namespace mozilla { namespace pkix {
+
+Result
+DigestSignedData(TrustDomain& trustDomain,
+                 const der::SignedDataWithSignature& signedData,
+                 /*out*/ uint8_t(&digestBuf)[MAX_DIGEST_SIZE_IN_BYTES],
+                 /*out*/ der::PublicKeyAlgorithm& publicKeyAlg,
+                 /*out*/ SignedDigest& signedDigest)
+{
+  Reader signatureAlg(signedData.algorithm);
+  Result rv = der::SignatureAlgorithmIdentifierValue(
+                signatureAlg, publicKeyAlg, signedDigest.digestAlgorithm);
+  if (rv != Success) {
+    return rv;
+  }
+  if (!signatureAlg.AtEnd()) {
+    return Result::ERROR_BAD_DER;
+  }
+
+  size_t digestLen;
+  switch (signedDigest.digestAlgorithm) {
+    case DigestAlgorithm::sha512: digestLen = 512 / 8; break;
+    case DigestAlgorithm::sha384: digestLen = 384 / 8; break;
+    case DigestAlgorithm::sha256: digestLen = 256 / 8; break;
+    case DigestAlgorithm::sha1: digestLen = 160 / 8; break;
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+  assert(digestLen <= sizeof(digestBuf));
+
+  rv = trustDomain.DigestBuf(signedData.data, signedDigest.digestAlgorithm,
+                             digestBuf, digestLen);
+  if (rv != Success) {
+    return rv;
+  }
+  rv = signedDigest.digest.Init(digestBuf, digestLen);
+  if (rv != Success) {
+    return rv;
+  }
+
+  return signedDigest.signature.Init(signedData.signature);
+}
+
+Result
+VerifySignedDigest(TrustDomain& trustDomain,
+                   der::PublicKeyAlgorithm publicKeyAlg,
+                   const SignedDigest& signedDigest,
+                   Input signerSubjectPublicKeyInfo)
+{
+  switch (publicKeyAlg) {
+    case der::PublicKeyAlgorithm::ECDSA:
+      return trustDomain.VerifyECDSASignedDigest(signedDigest,
+                                                 signerSubjectPublicKeyInfo);
+    case der::PublicKeyAlgorithm::RSA_PKCS1:
+      return trustDomain.VerifyRSAPKCS1SignedDigest(signedDigest,
+                                                    signerSubjectPublicKeyInfo);
+    MOZILLA_PKIX_UNREACHABLE_DEFAULT_ENUM
+  }
+}
+
+Result
+VerifySignedData(TrustDomain& trustDomain,
+                 const der::SignedDataWithSignature& signedData,
+                 Input signerSubjectPublicKeyInfo)
+{
+  uint8_t digestBuf[MAX_DIGEST_SIZE_IN_BYTES];
+  der::PublicKeyAlgorithm publicKeyAlg;
+  SignedDigest signedDigest;
+  Result rv = DigestSignedData(trustDomain, signedData, digestBuf,
+                               publicKeyAlg, signedDigest);
+  if (rv != Success) {
+    return rv;
+  }
+  return VerifySignedDigest(trustDomain, publicKeyAlg, signedDigest,
+                            signerSubjectPublicKeyInfo);
+}
+
+} } // namespace mozilla::pkix