Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 900 insertions, 0 deletions

diff --git a/security/nss/gtests/mozpkix_gtest/pkixbuild_tests.cpp b/security/nss/gtests/mozpkix_gtest/pkixbuild_tests.cpp
new file mode 100644
index 0000000000..df9a3d40e2
--- /dev/null
+++ b/security/nss/gtests/mozpkix_gtest/pkixbuild_tests.cpp
@@ -0,0 +1,900 @@
+/* -*- 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.
+ */
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+// When building with -D_HAS_EXCEPTIONS=0, MSVC's <xtree> header triggers
+// warning C4702: unreachable code.
+// https://connect.microsoft.com/VisualStudio/feedback/details/809962
+#pragma warning(push)
+#pragma warning(disable: 4702)
+#endif
+
+#include <map>
+#include <vector>
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#pragma warning(pop)
+#endif
+
+#include "pkixgtest.h"
+
+#include "mozpkix/pkixder.h"
+
+using namespace mozilla::pkix;
+using namespace mozilla::pkix::test;
+
+static ByteString
+CreateCert(const char* issuerCN, // null means "empty name"
+           const char* subjectCN, // null means "empty name"
+           EndEntityOrCA endEntityOrCA,
+           /*optional modified*/ std::map<ByteString, ByteString>*
+             subjectDERToCertDER = nullptr,
+           /*optional*/ const ByteString* extension = nullptr,
+           /*optional*/ const TestKeyPair* issuerKeyPair = nullptr,
+           /*optional*/ const TestKeyPair* subjectKeyPair = nullptr)
+{
+  static long serialNumberValue = 0;
+  ++serialNumberValue;
+  ByteString serialNumber(CreateEncodedSerialNumber(serialNumberValue));
+  EXPECT_FALSE(ENCODING_FAILED(serialNumber));
+
+  ByteString issuerDER(issuerCN ? CNToDERName(issuerCN) : Name(ByteString()));
+  ByteString subjectDER(subjectCN ? CNToDERName(subjectCN) : Name(ByteString()));
+
+  std::vector<ByteString> extensions;
+  if (endEntityOrCA == EndEntityOrCA::MustBeCA) {
+    ByteString basicConstraints =
+      CreateEncodedBasicConstraints(true, nullptr, Critical::Yes);
+    EXPECT_FALSE(ENCODING_FAILED(basicConstraints));
+    extensions.push_back(basicConstraints);
+  }
+  if (extension) {
+    extensions.push_back(*extension);
+  }
+  extensions.push_back(ByteString()); // marks the end of the list
+
+  ScopedTestKeyPair reusedKey(CloneReusedKeyPair());
+  ByteString certDER(CreateEncodedCertificate(
+                       v3, sha256WithRSAEncryption(), serialNumber, issuerDER,
+                       oneDayBeforeNow, oneDayAfterNow, subjectDER,
+                       subjectKeyPair ? *subjectKeyPair : *reusedKey,
+                       extensions.data(),
+                       issuerKeyPair ? *issuerKeyPair : *reusedKey,
+                       sha256WithRSAEncryption()));
+  EXPECT_FALSE(ENCODING_FAILED(certDER));
+
+  if (subjectDERToCertDER) {
+    (*subjectDERToCertDER)[subjectDER] = certDER;
+  }
+
+  return certDER;
+}
+
+class TestTrustDomain final : public DefaultCryptoTrustDomain
+{
+public:
+  // The "cert chain tail" is a longish chain of certificates that is used by
+  // all of the tests here. We share this chain across all the tests in order
+  // to speed up the tests (generating keypairs for the certs is very slow).
+  bool SetUpCertChainTail()
+  {
+    static char const* const names[] = {
+        "CA1 (Root)", "CA2", "CA3", "CA4", "CA5", "CA6", "CA7"
+    };
+
+    for (size_t i = 0; i < MOZILLA_PKIX_ARRAY_LENGTH(names); ++i) {
+      const char* issuerName = i == 0 ? names[0] : names[i-1];
+      CreateCACert(issuerName, names[i]);
+      if (i == 0) {
+        rootCACertDER = leafCACertDER;
+      }
+    }
+
+    return true;
+  }
+
+  void CreateCACert(const char* issuerName, const char* subjectName)
+  {
+    leafCACertDER = CreateCert(issuerName, subjectName,
+                               EndEntityOrCA::MustBeCA, &subjectDERToCertDER);
+    assert(!ENCODING_FAILED(leafCACertDER));
+  }
+
+  ByteString GetLeafCACertDER() const { return leafCACertDER; }
+
+private:
+  Result GetCertTrust(EndEntityOrCA, const CertPolicyId&, Input candidateCert,
+                      /*out*/ TrustLevel& trustLevel) override
+  {
+    trustLevel = InputEqualsByteString(candidateCert, rootCACertDER)
+               ? TrustLevel::TrustAnchor
+               : TrustLevel::InheritsTrust;
+    return Success;
+  }
+
+  Result FindIssuer(Input encodedIssuerName, IssuerChecker& checker, Time)
+                    override
+  {
+    ByteString subjectDER(InputToByteString(encodedIssuerName));
+    ByteString certDER(subjectDERToCertDER[subjectDER]);
+    Input derCert;
+    Result rv = derCert.Init(certDER.data(), certDER.length());
+    if (rv != Success) {
+      return rv;
+    }
+    bool keepGoing;
+    rv = checker.Check(derCert, nullptr/*additionalNameConstraints*/,
+                       keepGoing);
+    if (rv != Success) {
+      return rv;
+    }
+    return Success;
+  }
+
+  Result CheckRevocation(EndEntityOrCA, const CertID&, Time, Duration,
+                         /*optional*/ const Input*, /*optional*/ const Input*,
+                         /*optional*/ const Input*)
+                         override
+  {
+    return Success;
+  }
+
+  Result IsChainValid(const DERArray&, Time, const CertPolicyId&) override
+  {
+    return Success;
+  }
+
+  std::map<ByteString, ByteString> subjectDERToCertDER;
+  ByteString leafCACertDER;
+  ByteString rootCACertDER;
+};
+
+class pkixbuild : public ::testing::Test
+{
+public:
+  static void SetUpTestSuite()
+  {
+    if (!trustDomain.SetUpCertChainTail()) {
+      abort();
+    }
+  }
+
+protected:
+
+  static TestTrustDomain trustDomain;
+};
+
+/*static*/ TestTrustDomain pkixbuild::trustDomain;
+
+TEST_F(pkixbuild, MaxAcceptableCertChainLength)
+{
+  {
+    ByteString leafCACert(trustDomain.GetLeafCACertDER());
+    Input certDER;
+    ASSERT_EQ(Success, certDER.Init(leafCACert.data(), leafCACert.length()));
+    ASSERT_EQ(Success,
+              BuildCertChain(trustDomain, certDER, Now(),
+                             EndEntityOrCA::MustBeCA,
+                             KeyUsage::noParticularKeyUsageRequired,
+                             KeyPurposeId::id_kp_serverAuth,
+                             CertPolicyId::anyPolicy,
+                             nullptr/*stapledOCSPResponse*/));
+  }
+
+  {
+    ByteString certDER(CreateCert("CA7", "Direct End-Entity",
+                                  EndEntityOrCA::MustBeEndEntity));
+    ASSERT_FALSE(ENCODING_FAILED(certDER));
+    Input certDERInput;
+    ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+    ASSERT_EQ(Success,
+              BuildCertChain(trustDomain, certDERInput, Now(),
+                             EndEntityOrCA::MustBeEndEntity,
+                             KeyUsage::noParticularKeyUsageRequired,
+                             KeyPurposeId::id_kp_serverAuth,
+                             CertPolicyId::anyPolicy,
+                             nullptr/*stapledOCSPResponse*/));
+  }
+}
+
+TEST_F(pkixbuild, BeyondMaxAcceptableCertChainLength)
+{
+  static char const* const caCertName = "CA Too Far";
+
+  trustDomain.CreateCACert("CA7", caCertName);
+
+  {
+    ByteString certDER(trustDomain.GetLeafCACertDER());
+    Input certDERInput;
+    ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+    ASSERT_EQ(Result::ERROR_UNKNOWN_ISSUER,
+              BuildCertChain(trustDomain, certDERInput, Now(),
+                             EndEntityOrCA::MustBeCA,
+                             KeyUsage::noParticularKeyUsageRequired,
+                             KeyPurposeId::id_kp_serverAuth,
+                             CertPolicyId::anyPolicy,
+                             nullptr/*stapledOCSPResponse*/));
+  }
+
+  {
+    ByteString certDER(CreateCert(caCertName, "End-Entity Too Far",
+                                  EndEntityOrCA::MustBeEndEntity));
+    ASSERT_FALSE(ENCODING_FAILED(certDER));
+    Input certDERInput;
+    ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+    ASSERT_EQ(Result::ERROR_UNKNOWN_ISSUER,
+              BuildCertChain(trustDomain, certDERInput, Now(),
+                             EndEntityOrCA::MustBeEndEntity,
+                             KeyUsage::noParticularKeyUsageRequired,
+                             KeyPurposeId::id_kp_serverAuth,
+                             CertPolicyId::anyPolicy,
+                             nullptr/*stapledOCSPResponse*/));
+  }
+}
+
+// A TrustDomain that checks certificates against a given root certificate.
+// It is initialized with the DER encoding of a root certificate that
+// is treated as a trust anchor and is assumed to have issued all certificates
+// (i.e. FindIssuer always attempts to build the next step in the chain with
+// it).
+class SingleRootTrustDomain : public DefaultCryptoTrustDomain
+{
+public:
+  explicit SingleRootTrustDomain(ByteString aRootDER)
+    : rootDER(aRootDER)
+  {
+  }
+
+  // The CertPolicyId argument is unused because we don't care about EV.
+  Result GetCertTrust(EndEntityOrCA, const CertPolicyId&, Input candidateCert,
+                      /*out*/ TrustLevel& trustLevel) override
+  {
+    Input rootCert;
+    Result rv = rootCert.Init(rootDER.data(), rootDER.length());
+    if (rv != Success) {
+      return rv;
+    }
+    if (InputsAreEqual(candidateCert, rootCert)) {
+      trustLevel = TrustLevel::TrustAnchor;
+    } else {
+      trustLevel = TrustLevel::InheritsTrust;
+    }
+    return Success;
+  }
+
+  Result FindIssuer(Input, IssuerChecker& checker, Time) override
+  {
+    // keepGoing is an out parameter from IssuerChecker.Check. It would tell us
+    // whether or not to continue attempting other potential issuers. We only
+    // know of one potential issuer, however, so we ignore it.
+    bool keepGoing;
+    Input rootCert;
+    Result rv = rootCert.Init(rootDER.data(), rootDER.length());
+    if (rv != Success) {
+      return rv;
+    }
+    return checker.Check(rootCert, nullptr, keepGoing);
+  }
+
+  Result IsChainValid(const DERArray&, Time, const CertPolicyId&) override
+  {
+    return Success;
+  }
+
+  Result CheckRevocation(EndEntityOrCA, const CertID&, Time, Duration,
+                         /*optional*/ const Input*, /*optional*/ const Input*,
+                         /*optional*/ const Input*)
+                         override
+  {
+    return Success;
+  }
+
+private:
+  ByteString rootDER;
+};
+
+// A TrustDomain that explicitly fails if CheckRevocation is called.
+class ExpiredCertTrustDomain final : public SingleRootTrustDomain
+{
+public:
+  explicit ExpiredCertTrustDomain(ByteString aRootDER)
+    : SingleRootTrustDomain(aRootDER)
+  {
+  }
+
+  Result CheckRevocation(EndEntityOrCA, const CertID&, Time, Duration,
+                         /*optional*/ const Input*, /*optional*/ const Input*,
+                         /*optional*/ const Input*)
+                         override
+  {
+    ADD_FAILURE();
+    return NotReached("CheckRevocation should not be called",
+                      Result::FATAL_ERROR_LIBRARY_FAILURE);
+  }
+};
+
+TEST_F(pkixbuild, NoRevocationCheckingForExpiredCert)
+{
+  const char* rootCN = "Root CA";
+  ByteString rootDER(CreateCert(rootCN, rootCN, EndEntityOrCA::MustBeCA,
+                                nullptr));
+  EXPECT_FALSE(ENCODING_FAILED(rootDER));
+  ExpiredCertTrustDomain expiredCertTrustDomain(rootDER);
+
+  ByteString serialNumber(CreateEncodedSerialNumber(100));
+  EXPECT_FALSE(ENCODING_FAILED(serialNumber));
+  ByteString issuerDER(CNToDERName(rootCN));
+  ByteString subjectDER(CNToDERName("Expired End-Entity Cert"));
+  ScopedTestKeyPair reusedKey(CloneReusedKeyPair());
+  ByteString certDER(CreateEncodedCertificate(
+                       v3, sha256WithRSAEncryption(),
+                       serialNumber, issuerDER,
+                       twoDaysBeforeNow,
+                       oneDayBeforeNow,
+                       subjectDER, *reusedKey, nullptr, *reusedKey,
+                       sha256WithRSAEncryption()));
+  EXPECT_FALSE(ENCODING_FAILED(certDER));
+
+  Input cert;
+  ASSERT_EQ(Success, cert.Init(certDER.data(), certDER.length()));
+  ASSERT_EQ(Result::ERROR_EXPIRED_CERTIFICATE,
+            BuildCertChain(expiredCertTrustDomain, cert, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr));
+}
+
+class DSSTrustDomain final : public EverythingFailsByDefaultTrustDomain
+{
+public:
+  Result GetCertTrust(EndEntityOrCA, const CertPolicyId&,
+                      Input, /*out*/ TrustLevel& trustLevel) override
+  {
+    trustLevel = TrustLevel::TrustAnchor;
+    return Success;
+  }
+};
+
+class pkixbuild_DSS : public ::testing::Test { };
+
+TEST_F(pkixbuild_DSS, DSSEndEntityKeyNotAccepted)
+{
+  DSSTrustDomain trustDomain;
+
+  ByteString serialNumber(CreateEncodedSerialNumber(1));
+  ASSERT_FALSE(ENCODING_FAILED(serialNumber));
+
+  ByteString subjectDER(CNToDERName("DSS"));
+  ASSERT_FALSE(ENCODING_FAILED(subjectDER));
+  ScopedTestKeyPair subjectKey(GenerateDSSKeyPair());
+  ASSERT_TRUE(subjectKey.get());
+
+  ByteString issuerDER(CNToDERName("RSA"));
+  ASSERT_FALSE(ENCODING_FAILED(issuerDER));
+  ScopedTestKeyPair issuerKey(CloneReusedKeyPair());
+  ASSERT_TRUE(issuerKey.get());
+
+  ByteString cert(CreateEncodedCertificate(v3, sha256WithRSAEncryption(),
+                                           serialNumber, issuerDER,
+                                           oneDayBeforeNow, oneDayAfterNow,
+                                           subjectDER, *subjectKey, nullptr,
+                                           *issuerKey, sha256WithRSAEncryption()));
+  ASSERT_FALSE(ENCODING_FAILED(cert));
+  Input certDER;
+  ASSERT_EQ(Success, certDER.Init(cert.data(), cert.length()));
+
+  ASSERT_EQ(Result::ERROR_UNSUPPORTED_KEYALG,
+            BuildCertChain(trustDomain, certDER, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr/*stapledOCSPResponse*/));
+}
+
+class IssuerNameCheckTrustDomain final : public DefaultCryptoTrustDomain
+{
+public:
+  IssuerNameCheckTrustDomain(const ByteString& aIssuer, bool aExpectedKeepGoing)
+    : issuer(aIssuer)
+    , expectedKeepGoing(aExpectedKeepGoing)
+  {
+  }
+
+  Result GetCertTrust(EndEntityOrCA endEntityOrCA, const CertPolicyId&, Input,
+                      /*out*/ TrustLevel& trustLevel) override
+  {
+    trustLevel = endEntityOrCA == EndEntityOrCA::MustBeCA
+               ? TrustLevel::TrustAnchor
+               : TrustLevel::InheritsTrust;
+    return Success;
+  }
+
+  Result FindIssuer(Input, IssuerChecker& checker, Time) override
+  {
+    Input issuerInput;
+    EXPECT_EQ(Success, issuerInput.Init(issuer.data(), issuer.length()));
+    bool keepGoing;
+    EXPECT_EQ(Success,
+              checker.Check(issuerInput, nullptr /*additionalNameConstraints*/,
+                            keepGoing));
+    EXPECT_EQ(expectedKeepGoing, keepGoing);
+    return Success;
+  }
+
+  Result CheckRevocation(EndEntityOrCA, const CertID&, Time, Duration,
+                         /*optional*/ const Input*, /*optional*/ const Input*,
+                         /*optional*/ const Input*)
+                         override
+  {
+    return Success;
+  }
+
+  Result IsChainValid(const DERArray&, Time, const CertPolicyId&) override
+  {
+    return Success;
+  }
+
+private:
+  const ByteString issuer;
+  const bool expectedKeepGoing;
+};
+
+struct IssuerNameCheckParams
+{
+  const char* subjectIssuerCN; // null means "empty name"
+  const char* issuerSubjectCN; // null means "empty name"
+  bool matches;
+  Result expectedError;
+};
+
+static const IssuerNameCheckParams ISSUER_NAME_CHECK_PARAMS[] =
+{
+  { "foo", "foo", true, Success },
+  { "foo", "bar", false, Result::ERROR_UNKNOWN_ISSUER },
+  { "f", "foo", false, Result::ERROR_UNKNOWN_ISSUER }, // prefix
+  { "foo", "f", false, Result::ERROR_UNKNOWN_ISSUER }, // prefix
+  { "foo", "Foo", false, Result::ERROR_UNKNOWN_ISSUER }, // case sensitive
+  { "", "", true, Success },
+  { nullptr, nullptr, false, Result::ERROR_EMPTY_ISSUER_NAME }, // empty issuer
+
+  // check that certificate-related errors are deferred and superseded by
+  // ERROR_UNKNOWN_ISSUER when a chain can't be built due to name mismatches
+  { "foo", nullptr, false, Result::ERROR_UNKNOWN_ISSUER },
+  { nullptr, "foo", false, Result::ERROR_UNKNOWN_ISSUER }
+};
+
+class pkixbuild_IssuerNameCheck
+  : public ::testing::Test
+  , public ::testing::WithParamInterface<IssuerNameCheckParams>
+{
+};
+
+TEST_P(pkixbuild_IssuerNameCheck, MatchingName)
+{
+  const IssuerNameCheckParams& params(GetParam());
+
+  ByteString issuerCertDER(CreateCert(params.issuerSubjectCN,
+                                      params.issuerSubjectCN,
+                                      EndEntityOrCA::MustBeCA, nullptr));
+  ASSERT_FALSE(ENCODING_FAILED(issuerCertDER));
+
+  ByteString subjectCertDER(CreateCert(params.subjectIssuerCN, "end-entity",
+                                       EndEntityOrCA::MustBeEndEntity,
+                                       nullptr));
+  ASSERT_FALSE(ENCODING_FAILED(subjectCertDER));
+
+  Input subjectCertDERInput;
+  ASSERT_EQ(Success, subjectCertDERInput.Init(subjectCertDER.data(),
+                                              subjectCertDER.length()));
+
+  IssuerNameCheckTrustDomain trustDomain(issuerCertDER, !params.matches);
+  ASSERT_EQ(params.expectedError,
+            BuildCertChain(trustDomain, subjectCertDERInput, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr/*stapledOCSPResponse*/));
+}
+
+INSTANTIATE_TEST_SUITE_P(pkixbuild_IssuerNameCheck, pkixbuild_IssuerNameCheck,
+                        testing::ValuesIn(ISSUER_NAME_CHECK_PARAMS));
+
+
+// Records the embedded SCT list extension for later examination.
+class EmbeddedSCTListTestTrustDomain final : public SingleRootTrustDomain
+{
+public:
+  explicit EmbeddedSCTListTestTrustDomain(ByteString aRootDER)
+    : SingleRootTrustDomain(aRootDER)
+  {
+  }
+
+  virtual void NoteAuxiliaryExtension(AuxiliaryExtension extension,
+                                      Input extensionData) override
+  {
+    if (extension == AuxiliaryExtension::EmbeddedSCTList) {
+      signedCertificateTimestamps = InputToByteString(extensionData);
+    } else {
+      ADD_FAILURE();
+    }
+  }
+
+  ByteString signedCertificateTimestamps;
+};
+
+TEST_F(pkixbuild, CertificateTransparencyExtension)
+{
+  // python security/pkix/tools/DottedOIDToCode.py --tlv
+  //   id-embeddedSctList 1.3.6.1.4.1.11129.2.4.2
+  static const uint8_t tlv_id_embeddedSctList[] = {
+    0x06, 0x0a, 0x2b, 0x06, 0x01, 0x04, 0x01, 0xd6, 0x79, 0x02, 0x04, 0x02
+  };
+  static const uint8_t dummySctList[] = {
+    0x01, 0x02, 0x03, 0x04, 0x05
+  };
+
+  ByteString ctExtension = TLV(der::SEQUENCE,
+    BytesToByteString(tlv_id_embeddedSctList) +
+    Boolean(false) +
+    TLV(der::OCTET_STRING,
+      // SignedCertificateTimestampList structure is encoded as an OCTET STRING
+      // within the X.509v3 extension (see RFC 6962 section 3.3).
+      // pkix decodes it internally and returns the actual structure.
+      TLV(der::OCTET_STRING, BytesToByteString(dummySctList))));
+
+  const char* rootCN = "Root CA";
+  ByteString rootDER(CreateCert(rootCN, rootCN, EndEntityOrCA::MustBeCA));
+  ASSERT_FALSE(ENCODING_FAILED(rootDER));
+
+  ByteString certDER(CreateCert(rootCN, "Cert with SCT list",
+                                EndEntityOrCA::MustBeEndEntity,
+                                nullptr, /*subjectDERToCertDER*/
+                                &ctExtension));
+  ASSERT_FALSE(ENCODING_FAILED(certDER));
+
+  Input certInput;
+  ASSERT_EQ(Success, certInput.Init(certDER.data(), certDER.length()));
+
+  EmbeddedSCTListTestTrustDomain extTrustDomain(rootDER);
+  ASSERT_EQ(Success,
+            BuildCertChain(extTrustDomain, certInput, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::anyExtendedKeyUsage,
+                           CertPolicyId::anyPolicy,
+                           nullptr /*stapledOCSPResponse*/));
+  ASSERT_EQ(BytesToByteString(dummySctList),
+            extTrustDomain.signedCertificateTimestamps);
+}
+
+// This TrustDomain implements a hierarchy like so:
+//
+// A   B
+// |   |
+// C   D
+//  \ /
+//   E
+//
+// where A is a trust anchor, B is not a trust anchor and has no known issuer, C
+// and D are intermediates with the same subject and subject public key, and E
+// is an end-entity (in practice, the end-entity will be generated by the test
+// functions using this trust domain).
+class MultiplePathTrustDomain: public DefaultCryptoTrustDomain
+{
+public:
+  void SetUpCerts()
+  {
+    ASSERT_FALSE(ENCODING_FAILED(CreateCert("UntrustedRoot", "UntrustedRoot",
+                                            EndEntityOrCA::MustBeCA,
+                                            &subjectDERToCertDER)));
+    // The subject DER -> cert DER mapping would be overwritten for subject
+    // "Intermediate" when we create the second "Intermediate" certificate, so
+    // we keep a copy of this "Intermediate".
+    intermediateSignedByUntrustedRootCertDER =
+      CreateCert("UntrustedRoot", "Intermediate", EndEntityOrCA::MustBeCA);
+    ASSERT_FALSE(ENCODING_FAILED(intermediateSignedByUntrustedRootCertDER));
+    rootCACertDER = CreateCert("TrustedRoot", "TrustedRoot",
+                               EndEntityOrCA::MustBeCA, &subjectDERToCertDER);
+    ASSERT_FALSE(ENCODING_FAILED(rootCACertDER));
+    ASSERT_FALSE(ENCODING_FAILED(CreateCert("TrustedRoot", "Intermediate",
+                                            EndEntityOrCA::MustBeCA,
+                                            &subjectDERToCertDER)));
+  }
+
+private:
+  Result GetCertTrust(EndEntityOrCA, const CertPolicyId&, Input candidateCert,
+                      /*out*/ TrustLevel& trustLevel) override
+  {
+    trustLevel = InputEqualsByteString(candidateCert, rootCACertDER)
+               ? TrustLevel::TrustAnchor
+               : TrustLevel::InheritsTrust;
+    return Success;
+  }
+
+  Result CheckCert(ByteString& certDER, IssuerChecker& checker, bool& keepGoing)
+  {
+    Input derCert;
+    Result rv = derCert.Init(certDER.data(), certDER.length());
+    if (rv != Success) {
+      return rv;
+    }
+    return checker.Check(derCert, nullptr/*additionalNameConstraints*/,
+                         keepGoing);
+  }
+
+  Result FindIssuer(Input encodedIssuerName, IssuerChecker& checker, Time)
+                    override
+  {
+    ByteString subjectDER(InputToByteString(encodedIssuerName));
+    ByteString certDER(subjectDERToCertDER[subjectDER]);
+    assert(!ENCODING_FAILED(certDER));
+    bool keepGoing;
+    Result rv = CheckCert(certDER, checker, keepGoing);
+    if (rv != Success) {
+      return rv;
+    }
+    // Also try the other intermediate.
+    if (keepGoing) {
+      rv = CheckCert(intermediateSignedByUntrustedRootCertDER, checker,
+                     keepGoing);
+      if (rv != Success) {
+        return rv;
+      }
+    }
+    return Success;
+  }
+
+  Result CheckRevocation(EndEntityOrCA, const CertID&, Time, Duration,
+                         /*optional*/ const Input*,
+                         /*optional*/ const Input*,
+                         /*optional*/ const Input*) override
+  {
+    return Success;
+  }
+
+  Result IsChainValid(const DERArray&, Time, const CertPolicyId&) override
+  {
+    return Success;
+  }
+
+  std::map<ByteString, ByteString> subjectDERToCertDER;
+  ByteString rootCACertDER;
+  ByteString intermediateSignedByUntrustedRootCertDER;
+};
+
+TEST_F(pkixbuild, BadEmbeddedSCTWithMultiplePaths)
+{
+  MultiplePathTrustDomain localTrustDomain;
+  localTrustDomain.SetUpCerts();
+
+  // python security/pkix/tools/DottedOIDToCode.py --tlv
+  //   id-embeddedSctList 1.3.6.1.4.1.11129.2.4.2
+  static const uint8_t tlv_id_embeddedSctList[] = {
+    0x06, 0x0a, 0x2b, 0x06, 0x01, 0x04, 0x01, 0xd6, 0x79, 0x02, 0x04, 0x02
+  };
+  static const uint8_t dummySctList[] = {
+    0x01, 0x02, 0x03, 0x04, 0x05
+  };
+  ByteString ctExtension = TLV(der::SEQUENCE,
+    BytesToByteString(tlv_id_embeddedSctList) +
+    Boolean(false) +
+    // The contents of the OCTET STRING are supposed to consist of an OCTET
+    // STRING of useful data. We're testing what happens if it isn't, so shove
+    // some bogus (non-OCTET STRING) data in there.
+    TLV(der::OCTET_STRING, BytesToByteString(dummySctList)));
+  ByteString certDER(CreateCert("Intermediate", "Cert with bogus SCT list",
+                                EndEntityOrCA::MustBeEndEntity,
+                                nullptr, /*subjectDERToCertDER*/
+                                &ctExtension));
+  ASSERT_FALSE(ENCODING_FAILED(certDER));
+  Input certDERInput;
+  ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+  ASSERT_EQ(Result::ERROR_BAD_DER,
+            BuildCertChain(localTrustDomain, certDERInput, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr/*stapledOCSPResponse*/));
+}
+
+// Same as a MultiplePathTrustDomain, but the end-entity is revoked.
+class RevokedEndEntityTrustDomain final : public MultiplePathTrustDomain
+{
+public:
+  Result CheckRevocation(EndEntityOrCA endEntityOrCA, const CertID&, Time,
+                         Duration, /*optional*/ const Input*,
+                         /*optional*/ const Input*, /*optional*/ const Input*) override
+  {
+    if (endEntityOrCA == EndEntityOrCA::MustBeEndEntity) {
+      return Result::ERROR_REVOKED_CERTIFICATE;
+    }
+    return Success;
+  }
+};
+
+TEST_F(pkixbuild, RevokedEndEntityWithMultiplePaths)
+{
+  RevokedEndEntityTrustDomain localTrustDomain;
+  localTrustDomain.SetUpCerts();
+  ByteString certDER(CreateCert("Intermediate", "RevokedEndEntity",
+                                EndEntityOrCA::MustBeEndEntity));
+  ASSERT_FALSE(ENCODING_FAILED(certDER));
+  Input certDERInput;
+  ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+  ASSERT_EQ(Result::ERROR_REVOKED_CERTIFICATE,
+            BuildCertChain(localTrustDomain, certDERInput, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr/*stapledOCSPResponse*/));
+}
+
+// This represents a collection of different certificates that all have the same
+// subject and issuer distinguished name.
+class SelfIssuedCertificatesTrustDomain final : public DefaultCryptoTrustDomain
+{
+public:
+  void SetUpCerts(size_t totalCerts)
+  {
+    ASSERT_TRUE(totalCerts > 0);
+    // First we generate a trust anchor.
+    ScopedTestKeyPair rootKeyPair(GenerateKeyPair());
+    rootCACertDER = CreateCert("DN", "DN", EndEntityOrCA::MustBeCA, nullptr,
+                               nullptr, rootKeyPair.get(), rootKeyPair.get());
+    ASSERT_FALSE(ENCODING_FAILED(rootCACertDER));
+    certs.push_back(rootCACertDER);
+    ScopedTestKeyPair issuerKeyPair(rootKeyPair.release());
+    size_t subCAsGenerated;
+    // Then we generate 6 sub-CAs (given that we were requested to generate at
+    // least that many).
+    for (subCAsGenerated = 0;
+         subCAsGenerated < totalCerts - 1 && subCAsGenerated < 6;
+         subCAsGenerated++) {
+      // Each certificate has to have a unique SPKI (mozilla::pkix does loop
+      // detection and stops searching if it encounters two certificates in a
+      // path with the same subject and SPKI).
+      ScopedTestKeyPair keyPair(GenerateKeyPair());
+      ByteString cert(CreateCert("DN", "DN", EndEntityOrCA::MustBeCA, nullptr,
+                                 nullptr, issuerKeyPair.get(), keyPair.get()));
+      ASSERT_FALSE(ENCODING_FAILED(cert));
+      certs.push_back(cert);
+      issuerKeyPair.reset(keyPair.release());
+    }
+    // We set firstIssuerKey here because we can't end up with a path that has
+    // more than 7 CAs in it (because mozilla::pkix limits the path length).
+    firstIssuerKey.reset(issuerKeyPair.release());
+    // For any more sub CAs we generate, it doesn't matter what their keys are
+    // as long as they're different.
+    for (; subCAsGenerated < totalCerts - 1; subCAsGenerated++) {
+      ScopedTestKeyPair keyPair(GenerateKeyPair());
+      ByteString cert(CreateCert("DN", "DN", EndEntityOrCA::MustBeCA, nullptr,
+                                 nullptr, keyPair.get(), keyPair.get()));
+      ASSERT_FALSE(ENCODING_FAILED(cert));
+      certs.insert(certs.begin(), cert);
+    }
+  }
+
+  const TestKeyPair* GetFirstIssuerKey()
+  {
+    return firstIssuerKey.get();
+  }
+
+private:
+  Result GetCertTrust(EndEntityOrCA, const CertPolicyId&, Input candidateCert,
+                      /*out*/ TrustLevel& trustLevel) override
+  {
+    trustLevel = InputEqualsByteString(candidateCert, rootCACertDER)
+               ? TrustLevel::TrustAnchor
+               : TrustLevel::InheritsTrust;
+    return Success;
+  }
+
+  Result FindIssuer(Input, IssuerChecker& checker, Time) override
+  {
+    bool keepGoing;
+    for (auto& cert: certs) {
+      Input certInput;
+      Result rv = certInput.Init(cert.data(), cert.length());
+      if (rv != Success) {
+        return rv;
+      }
+      rv = checker.Check(certInput, nullptr, keepGoing);
+      if (rv != Success || !keepGoing) {
+        return rv;
+      }
+    }
+    return Success;
+  }
+
+  Result CheckRevocation(EndEntityOrCA, const CertID&, Time, Duration,
+                         /*optional*/ const Input*, /*optional*/ const Input*,
+                         /*optional*/ const Input*)
+                         override
+  {
+    return Success;
+  }
+
+  Result IsChainValid(const DERArray&, Time, const CertPolicyId&) override
+  {
+    return Success;
+  }
+
+  std::vector<ByteString> certs;
+  ByteString rootCACertDER;
+  ScopedTestKeyPair firstIssuerKey;
+};
+
+TEST_F(pkixbuild, AvoidUnboundedPathSearchingFailure)
+{
+  SelfIssuedCertificatesTrustDomain localTrustDomain;
+  // This creates a few hundred million potential paths of length 8 (end entity
+  // + 6 sub-CAs + root). It would be prohibitively expensive to enumerate all
+  // of these, so we give mozilla::pkix a budget that is spent when searching
+  // paths. If the budget is exhausted, it simply returns an unknown issuer
+  // error. In the future it might be nice to return a specific error that would
+  // give the front-end a hint that maybe it shouldn't have so many certificates
+  // that all have the same subject and issuer DN but different SPKIs.
+  localTrustDomain.SetUpCerts(18);
+  ByteString certDER(CreateCert("DN", "DN", EndEntityOrCA::MustBeEndEntity,
+                                nullptr, nullptr,
+                                localTrustDomain.GetFirstIssuerKey()));
+  ASSERT_FALSE(ENCODING_FAILED(certDER));
+  Input certDERInput;
+  ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+  ASSERT_EQ(Result::ERROR_UNKNOWN_ISSUER,
+            BuildCertChain(localTrustDomain, certDERInput, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr/*stapledOCSPResponse*/));
+}
+
+TEST_F(pkixbuild, AvoidUnboundedPathSearchingSuccess)
+{
+  SelfIssuedCertificatesTrustDomain localTrustDomain;
+  // This creates a few hundred thousand possible potential paths of length 8
+  // (end entity + 6 sub-CAs + root). This will nearly exhaust mozilla::pkix's
+  // search budget, so this should succeed.
+  localTrustDomain.SetUpCerts(10);
+  ByteString certDER(CreateCert("DN", "DN", EndEntityOrCA::MustBeEndEntity,
+                                nullptr, nullptr,
+                                localTrustDomain.GetFirstIssuerKey()));
+  ASSERT_FALSE(ENCODING_FAILED(certDER));
+  Input certDERInput;
+  ASSERT_EQ(Success, certDERInput.Init(certDER.data(), certDER.length()));
+  ASSERT_EQ(Success,
+            BuildCertChain(localTrustDomain, certDERInput, Now(),
+                           EndEntityOrCA::MustBeEndEntity,
+                           KeyUsage::noParticularKeyUsageRequired,
+                           KeyPurposeId::id_kp_serverAuth,
+                           CertPolicyId::anyPolicy,
+                           nullptr/*stapledOCSPResponse*/));
+}