| // Copyright 2019 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include <algorithm> |
| #include <iterator> |
| |
| #include "cert_errors.h" |
| #include "crl.h" |
| #include "revocation_util.h" |
| #include "signature_algorithm.h" |
| #include "verify_name_match.h" |
| #include "verify_signed_data.h" |
| #include "input.h" |
| #include "parse_values.h" |
| #include "parser.h" |
| #include "tag.h" |
| |
| namespace bssl { |
| |
| namespace { |
| |
| // id-ce-issuingDistributionPoint OBJECT IDENTIFIER ::= { id-ce 28 } |
| // In dotted notation: 2.5.29.28 |
| inline constexpr uint8_t kIssuingDistributionPointOid[] = {0x55, 0x1d, 0x1c}; |
| |
| [[nodiscard]] bool NormalizeNameTLV(const der::Input& name_tlv, |
| std::string* out_normalized_name) { |
| der::Parser parser(name_tlv); |
| der::Input name_rdn; |
| bssl::CertErrors unused_errors; |
| return parser.ReadTag(der::kSequence, &name_rdn) && |
| NormalizeName(name_rdn, out_normalized_name, &unused_errors) && |
| !parser.HasMore(); |
| } |
| |
| bool ContainsExactMatchingName(std::vector<std::string_view> a, |
| std::vector<std::string_view> b) { |
| std::sort(a.begin(), a.end()); |
| std::sort(b.begin(), b.end()); |
| std::vector<std::string_view> names_in_common; |
| std::set_intersection(a.begin(), a.end(), b.begin(), b.end(), |
| std::back_inserter(names_in_common)); |
| return !names_in_common.empty(); |
| } |
| |
| } // namespace |
| |
| bool ParseCrlCertificateList(const der::Input& crl_tlv, |
| der::Input* out_tbs_cert_list_tlv, |
| der::Input* out_signature_algorithm_tlv, |
| der::BitString* out_signature_value) { |
| der::Parser parser(crl_tlv); |
| |
| // CertificateList ::= SEQUENCE { |
| der::Parser certificate_list_parser; |
| if (!parser.ReadSequence(&certificate_list_parser)) |
| return false; |
| |
| // tbsCertList TBSCertList |
| if (!certificate_list_parser.ReadRawTLV(out_tbs_cert_list_tlv)) |
| return false; |
| |
| // signatureAlgorithm AlgorithmIdentifier, |
| if (!certificate_list_parser.ReadRawTLV(out_signature_algorithm_tlv)) |
| return false; |
| |
| // signatureValue BIT STRING } |
| std::optional<der::BitString> signature_value = |
| certificate_list_parser.ReadBitString(); |
| if (!signature_value) |
| return false; |
| *out_signature_value = signature_value.value(); |
| |
| // There isn't an extension point at the end of CertificateList. |
| if (certificate_list_parser.HasMore()) |
| return false; |
| |
| // By definition the input was a single CertificateList, so there shouldn't be |
| // unconsumed data. |
| if (parser.HasMore()) |
| return false; |
| |
| return true; |
| } |
| |
| bool ParseCrlTbsCertList(const der::Input& tbs_tlv, ParsedCrlTbsCertList* out) { |
| der::Parser parser(tbs_tlv); |
| |
| // TBSCertList ::= SEQUENCE { |
| der::Parser tbs_parser; |
| if (!parser.ReadSequence(&tbs_parser)) |
| return false; |
| |
| // version Version OPTIONAL, |
| // -- if present, MUST be v2 |
| std::optional<der::Input> version_der; |
| if (!tbs_parser.ReadOptionalTag(der::kInteger, &version_der)) |
| return false; |
| if (version_der.has_value()) { |
| uint64_t version64; |
| if (!der::ParseUint64(*version_der, &version64)) |
| return false; |
| // If version is present, it MUST be v2(1). |
| if (version64 != 1) |
| return false; |
| out->version = CrlVersion::V2; |
| } else { |
| // Uh, RFC 5280 doesn't actually say it anywhere, but presumably if version |
| // is not specified, it is V1. |
| out->version = CrlVersion::V1; |
| } |
| |
| // signature AlgorithmIdentifier, |
| if (!tbs_parser.ReadRawTLV(&out->signature_algorithm_tlv)) |
| return false; |
| |
| // issuer Name, |
| if (!tbs_parser.ReadRawTLV(&out->issuer_tlv)) |
| return false; |
| |
| // thisUpdate Time, |
| if (!ReadUTCOrGeneralizedTime(&tbs_parser, &out->this_update)) |
| return false; |
| |
| // nextUpdate Time OPTIONAL, |
| der::Tag maybe_next_update_tag; |
| der::Input unused_next_update_input; |
| if (tbs_parser.PeekTagAndValue(&maybe_next_update_tag, |
| &unused_next_update_input) && |
| (maybe_next_update_tag == der::kUtcTime || |
| maybe_next_update_tag == der::kGeneralizedTime)) { |
| der::GeneralizedTime next_update_time; |
| if (!ReadUTCOrGeneralizedTime(&tbs_parser, &next_update_time)) |
| return false; |
| out->next_update = next_update_time; |
| } else { |
| out->next_update = std::nullopt; |
| } |
| |
| // revokedCertificates SEQUENCE OF SEQUENCE { ... } OPTIONAL, |
| der::Input unused_revoked_certificates; |
| der::Tag maybe_revoked_certifigates_tag; |
| if (tbs_parser.PeekTagAndValue(&maybe_revoked_certifigates_tag, |
| &unused_revoked_certificates) && |
| maybe_revoked_certifigates_tag == der::kSequence) { |
| der::Input revoked_certificates_tlv; |
| if (!tbs_parser.ReadRawTLV(&revoked_certificates_tlv)) |
| return false; |
| out->revoked_certificates_tlv = revoked_certificates_tlv; |
| } else { |
| out->revoked_certificates_tlv = std::nullopt; |
| } |
| |
| // crlExtensions [0] EXPLICIT Extensions OPTIONAL |
| // -- if present, version MUST be v2 |
| if (!tbs_parser.ReadOptionalTag(der::ContextSpecificConstructed(0), |
| &out->crl_extensions_tlv)) { |
| return false; |
| } |
| if (out->crl_extensions_tlv.has_value()) { |
| if (out->version != CrlVersion::V2) |
| return false; |
| } |
| |
| if (tbs_parser.HasMore()) { |
| // Invalid or extraneous elements. |
| return false; |
| } |
| |
| // By definition the input was a single sequence, so there shouldn't be |
| // unconsumed data. |
| if (parser.HasMore()) |
| return false; |
| |
| return true; |
| } |
| |
| bool ParseIssuingDistributionPoint( |
| const der::Input& extension_value, |
| std::unique_ptr<GeneralNames>* out_distribution_point_names, |
| ContainedCertsType* out_only_contains_cert_type) { |
| der::Parser idp_extension_value_parser(extension_value); |
| // IssuingDistributionPoint ::= SEQUENCE { |
| der::Parser idp_parser; |
| if (!idp_extension_value_parser.ReadSequence(&idp_parser)) |
| return false; |
| |
| // 5.2.5. Conforming CRLs issuers MUST NOT issue CRLs where the DER |
| // encoding of the issuing distribution point extension is an empty |
| // sequence. |
| if (!idp_parser.HasMore()) |
| return false; |
| |
| // distributionPoint [0] DistributionPointName OPTIONAL, |
| std::optional<der::Input> distribution_point; |
| if (!idp_parser.ReadOptionalTag( |
| der::kTagContextSpecific | der::kTagConstructed | 0, |
| &distribution_point)) { |
| return false; |
| } |
| |
| if (distribution_point.has_value()) { |
| // DistributionPointName ::= CHOICE { |
| der::Parser dp_name_parser(*distribution_point); |
| // fullName [0] GeneralNames, |
| // nameRelativeToCRLIssuer [1] RelativeDistinguishedName } |
| std::optional<der::Input> der_full_name; |
| if (!dp_name_parser.ReadOptionalTag( |
| der::kTagContextSpecific | der::kTagConstructed | 0, |
| &der_full_name)) { |
| return false; |
| } |
| if (!der_full_name) { |
| // Only fullName is supported. |
| return false; |
| } |
| CertErrors errors; |
| *out_distribution_point_names = |
| GeneralNames::CreateFromValue(*der_full_name, &errors); |
| if (!*out_distribution_point_names) |
| return false; |
| |
| if (dp_name_parser.HasMore()) { |
| // CHOICE represents a single value. |
| return false; |
| } |
| } |
| |
| *out_only_contains_cert_type = ContainedCertsType::ANY_CERTS; |
| |
| // onlyContainsUserCerts [1] BOOLEAN DEFAULT FALSE, |
| std::optional<der::Input> only_contains_user_certs; |
| if (!idp_parser.ReadOptionalTag(der::kTagContextSpecific | 1, |
| &only_contains_user_certs)) { |
| return false; |
| } |
| if (only_contains_user_certs.has_value()) { |
| bool bool_value; |
| if (!der::ParseBool(*only_contains_user_certs, &bool_value)) |
| return false; |
| if (!bool_value) |
| return false; // DER-encoding requires DEFAULT values be omitted. |
| *out_only_contains_cert_type = ContainedCertsType::USER_CERTS; |
| } |
| |
| // onlyContainsCACerts [2] BOOLEAN DEFAULT FALSE, |
| std::optional<der::Input> only_contains_ca_certs; |
| if (!idp_parser.ReadOptionalTag(der::kTagContextSpecific | 2, |
| &only_contains_ca_certs)) { |
| return false; |
| } |
| if (only_contains_ca_certs.has_value()) { |
| bool bool_value; |
| if (!der::ParseBool(*only_contains_ca_certs, &bool_value)) |
| return false; |
| if (!bool_value) |
| return false; // DER-encoding requires DEFAULT values be omitted. |
| if (*out_only_contains_cert_type != ContainedCertsType::ANY_CERTS) { |
| // 5.2.5. at most one of onlyContainsUserCerts, onlyContainsCACerts, |
| // and onlyContainsAttributeCerts may be set to TRUE. |
| return false; |
| } |
| *out_only_contains_cert_type = ContainedCertsType::CA_CERTS; |
| } |
| |
| // onlySomeReasons [3] ReasonFlags OPTIONAL, |
| // indirectCRL [4] BOOLEAN DEFAULT FALSE, |
| // onlyContainsAttributeCerts [5] BOOLEAN DEFAULT FALSE } |
| // onlySomeReasons, indirectCRL, and onlyContainsAttributeCerts are not |
| // supported, fail parsing if they are present. |
| if (idp_parser.HasMore()) |
| return false; |
| |
| return true; |
| } |
| |
| CRLRevocationStatus GetCRLStatusForCert( |
| const der::Input& cert_serial, |
| CrlVersion crl_version, |
| const std::optional<der::Input>& revoked_certificates_tlv) { |
| if (!revoked_certificates_tlv.has_value()) { |
| // RFC 5280 Section 5.1.2.6: "When there are no revoked certificates, the |
| // revoked certificates list MUST be absent." |
| // No covered certificates are revoked, therefore the cert is good. |
| return CRLRevocationStatus::GOOD; |
| } |
| |
| der::Parser parser(*revoked_certificates_tlv); |
| |
| // revokedCertificates SEQUENCE OF SEQUENCE { |
| der::Parser revoked_certificates_parser; |
| if (!parser.ReadSequence(&revoked_certificates_parser)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // RFC 5280 Section 5.1.2.6: "When there are no revoked certificates, the |
| // revoked certificates list MUST be absent." |
| if (!revoked_certificates_parser.HasMore()) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // By definition the input was a single Extensions sequence, so there |
| // shouldn't be unconsumed data. |
| if (parser.HasMore()) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| bool found_matching_serial = false; |
| |
| while (revoked_certificates_parser.HasMore()) { |
| // revokedCertificates SEQUENCE OF SEQUENCE { |
| der::Parser crl_entry_parser; |
| if (!revoked_certificates_parser.ReadSequence(&crl_entry_parser)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| der::Input revoked_cert_serial_number; |
| // userCertificate CertificateSerialNumber, |
| if (!crl_entry_parser.ReadTag(der::kInteger, &revoked_cert_serial_number)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // revocationDate Time, |
| der::GeneralizedTime unused_revocation_date; |
| if (!ReadUTCOrGeneralizedTime(&crl_entry_parser, &unused_revocation_date)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // crlEntryExtensions Extensions OPTIONAL |
| if (crl_entry_parser.HasMore()) { |
| // -- if present, version MUST be v2 |
| if (crl_version != CrlVersion::V2) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| der::Input crl_entry_extensions_tlv; |
| if (!crl_entry_parser.ReadRawTLV(&crl_entry_extensions_tlv)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| std::map<der::Input, ParsedExtension> extensions; |
| if (!ParseExtensions(crl_entry_extensions_tlv, &extensions)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // RFC 5280 Section 5.3: "If a CRL contains a critical CRL entry |
| // extension that the application cannot process, then the application |
| // MUST NOT use that CRL to determine the status of any certificates." |
| for (const auto& ext : extensions) { |
| if (ext.second.critical) |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| } |
| |
| if (crl_entry_parser.HasMore()) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| if (revoked_cert_serial_number == cert_serial) { |
| // Cert is revoked, but can't return yet since there might be critical |
| // extensions on later entries that would prevent use of this CRL. |
| found_matching_serial = true; |
| } |
| } |
| |
| if (found_matching_serial) |
| return CRLRevocationStatus::REVOKED; |
| |
| // |cert| is not present in the revokedCertificates list. |
| return CRLRevocationStatus::GOOD; |
| } |
| |
| ParsedCrlTbsCertList::ParsedCrlTbsCertList() = default; |
| ParsedCrlTbsCertList::~ParsedCrlTbsCertList() = default; |
| |
| CRLRevocationStatus CheckCRL(std::string_view raw_crl, |
| const ParsedCertificateList& valid_chain, |
| size_t target_cert_index, |
| const ParsedDistributionPoint& cert_dp, |
| int64_t verify_time_epoch_seconds, |
| std::optional<int64_t> max_age_seconds) { |
| DCHECK_LT(target_cert_index, valid_chain.size()); |
| |
| if (cert_dp.reasons) { |
| // Reason codes are not supported. If the distribution point contains a |
| // subset of reasons then skip it. We aren't interested in subsets of CRLs |
| // and the RFC states that there MUST be a CRL that covers all reasons. |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| if (cert_dp.crl_issuer) { |
| // Indirect CRLs are not supported. |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| const ParsedCertificate* target_cert = valid_chain[target_cert_index].get(); |
| |
| // 6.3.3 (a) Update the local CRL cache by obtaining a complete CRL, a |
| // delta CRL, or both, as required. |
| // |
| // This implementation only supports complete CRLs and takes the CRL as |
| // input, it is up to the caller to provide an up to date CRL. |
| |
| der::Input tbs_cert_list_tlv; |
| der::Input signature_algorithm_tlv; |
| der::BitString signature_value; |
| if (!ParseCrlCertificateList(der::Input(raw_crl), &tbs_cert_list_tlv, |
| &signature_algorithm_tlv, &signature_value)) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| ParsedCrlTbsCertList tbs_cert_list; |
| if (!ParseCrlTbsCertList(tbs_cert_list_tlv, &tbs_cert_list)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // 5.1.1.2 signatureAlgorithm |
| // |
| // TODO(https://crbug.com/749276): Check the signature algorithm against |
| // policy. |
| std::optional<SignatureAlgorithm> signature_algorithm = |
| ParseSignatureAlgorithm(signature_algorithm_tlv); |
| if (!signature_algorithm) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| // This field MUST contain the same algorithm identifier as the |
| // signature field in the sequence tbsCertList (Section 5.1.2.2). |
| std::optional<SignatureAlgorithm> tbs_alg = |
| ParseSignatureAlgorithm(tbs_cert_list.signature_algorithm_tlv); |
| if (!tbs_alg || *signature_algorithm != *tbs_alg) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| // Check CRL dates. Roughly corresponds to 6.3.3 (a) (1) but does not attempt |
| // to update the CRL if it is out of date. |
| if (!CheckRevocationDateValid(tbs_cert_list.this_update, |
| tbs_cert_list.next_update.has_value() |
| ? &tbs_cert_list.next_update.value() |
| : nullptr, |
| verify_time_epoch_seconds, max_age_seconds)) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| // 6.3.3 (a) (2) is skipped: This implementation does not support delta CRLs. |
| |
| // 6.3.3 (b) Verify the issuer and scope of the complete CRL as follows: |
| // 6.3.3 (b) (1) If the DP includes cRLIssuer, then verify that the issuer |
| // field in the complete CRL matches cRLIssuer in the DP and |
| // that the complete CRL contains an issuing distribution |
| // point extension with the indirectCRL boolean asserted. |
| // |
| // Nothing is done here since distribution points with crlIssuer were skipped |
| // above. |
| |
| // 6.3.3 (b) (1) Otherwise, verify that the CRL issuer matches the |
| // certificate issuer. |
| // |
| // Normalization for the name comparison is used although the RFC is not |
| // clear on this. There are several places that explicitly are called out as |
| // requiring identical encodings: |
| // |
| // 4.2.1.13. CRL Distribution Points (cert extension) says the DP cRLIssuer |
| // field MUST be exactly the same as the encoding in issuer field of the |
| // CRL. |
| // |
| // 5.2.5. Issuing Distribution Point (crl extension) |
| // The identical encoding MUST be used in the distributionPoint fields |
| // of the certificate and the CRL. |
| // |
| // 5.3.3. Certificate Issuer (crl entry extension) also says "The encoding of |
| // the DN MUST be identical to the encoding used in the certificate" |
| // |
| // But 6.3.3 (b) (1) just says "matches". Also NIST PKITS includes at least |
| // one test that requires normalization here. |
| // TODO(https://crbug.com/749276): could do exact comparison first and only |
| // fall back to normalizing if that fails. |
| std::string normalized_crl_issuer; |
| if (!NormalizeNameTLV(tbs_cert_list.issuer_tlv, &normalized_crl_issuer)) |
| return CRLRevocationStatus::UNKNOWN; |
| if (der::Input(normalized_crl_issuer) != target_cert->normalized_issuer()) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| if (tbs_cert_list.crl_extensions_tlv.has_value()) { |
| std::map<der::Input, ParsedExtension> extensions; |
| if (!ParseExtensions(*tbs_cert_list.crl_extensions_tlv, &extensions)) |
| return CRLRevocationStatus::UNKNOWN; |
| |
| // 6.3.3 (b) (2) If the complete CRL includes an issuing distribution point |
| // (IDP) CRL extension, check the following: |
| ParsedExtension idp_extension; |
| if (ConsumeExtension(der::Input(kIssuingDistributionPointOid), &extensions, |
| &idp_extension)) { |
| std::unique_ptr<GeneralNames> distribution_point_names; |
| ContainedCertsType only_contains_cert_type; |
| if (!ParseIssuingDistributionPoint(idp_extension.value, |
| &distribution_point_names, |
| &only_contains_cert_type)) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| if (distribution_point_names) { |
| // 6.3.3. (b) (2) (i) If the distribution point name is present in the |
| // IDP CRL extension and the distribution field is |
| // present in the DP, then verify that one of the |
| // names in the IDP matches one of the names in the |
| // DP. |
| // 5.2.5. The identical encoding MUST be used in the distributionPoint |
| // fields of the certificate and the CRL. |
| // TODO(https://crbug.com/749276): Check other name types? |
| if (!cert_dp.distribution_point_fullname || |
| !ContainsExactMatchingName( |
| cert_dp.distribution_point_fullname |
| ->uniform_resource_identifiers, |
| distribution_point_names->uniform_resource_identifiers)) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| // 6.3.3. (b) (2) (i) If the distribution point name is present in the |
| // IDP CRL extension and the distribution field is |
| // omitted from the DP, then verify that one of the |
| // names in the IDP matches one of the names in the |
| // cRLIssuer field of the DP. |
| // Indirect CRLs are not supported, if indirectCRL was specified, |
| // ParseIssuingDistributionPoint would already have failed. |
| } |
| |
| switch (only_contains_cert_type) { |
| case ContainedCertsType::USER_CERTS: |
| // 6.3.3. (b) (2) (ii) If the onlyContainsUserCerts boolean is |
| // asserted in the IDP CRL extension, verify |
| // that the certificate does not include the |
| // basic constraints extension with the cA |
| // boolean asserted. |
| // 5.2.5. If either onlyContainsUserCerts or onlyContainsCACerts is |
| // set to TRUE, then the scope of the CRL MUST NOT include any |
| // version 1 or version 2 certificates. |
| if ((target_cert->has_basic_constraints() && |
| target_cert->basic_constraints().is_ca) || |
| target_cert->tbs().version == CertificateVersion::V1 || |
| target_cert->tbs().version == CertificateVersion::V2) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| break; |
| |
| case ContainedCertsType::CA_CERTS: |
| // 6.3.3. (b) (2) (iii) If the onlyContainsCACerts boolean is asserted |
| // in the IDP CRL extension, verify that the |
| // certificate includes the basic constraints |
| // extension with the cA boolean asserted. |
| // The version check is not done here, as the basicConstraints |
| // extension is required, and could not be present unless it is a V3 |
| // certificate. |
| if (!target_cert->has_basic_constraints() || |
| !target_cert->basic_constraints().is_ca) { |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| break; |
| |
| case ContainedCertsType::ANY_CERTS: |
| // (iv) Verify that the onlyContainsAttributeCerts |
| // boolean is not asserted. |
| // If onlyContainsAttributeCerts was present, |
| // ParseIssuingDistributionPoint would already have failed. |
| break; |
| } |
| } |
| |
| for (const auto& ext : extensions) { |
| // Fail if any unhandled critical CRL extensions are present. |
| if (ext.second.critical) |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| } |
| |
| // 6.3.3 (c-e) skipped: delta CRLs and reason codes are not supported. |
| |
| // This implementation only supports direct CRLs where the CRL was signed by |
| // one of the certs in its validated issuer chain. This allows handling some |
| // cases of key rollover without requiring additional CRL issuer cert |
| // discovery & path building. |
| // TODO(https://crbug.com/749276): should this loop start at |
| // |target_cert_index|? There doesn't seem to be anything in the specs that |
| // precludes a CRL signed by a self-issued cert from covering itself. On the |
| // other hand it seems like a pretty weird thing to allow and causes NIST |
| // PKITS 4.5.3 to pass when it seems like it would not be intended to (since |
| // issuingDistributionPoint CRL extension is not handled). |
| for (size_t i = target_cert_index + 1; i < valid_chain.size(); ++i) { |
| const ParsedCertificate* issuer_cert = valid_chain[i].get(); |
| |
| // 6.3.3 (f) Obtain and validate the certification path for the issuer of |
| // the complete CRL. The trust anchor for the certification |
| // path MUST be the same as the trust anchor used to validate |
| // the target certificate. |
| // |
| // As the |issuer_cert| is from the already validated chain, it is already |
| // known to chain to the same trust anchor as the target certificate. |
| if (der::Input(normalized_crl_issuer) != |
| issuer_cert->normalized_subject()) { |
| continue; |
| } |
| |
| // 6.3.3 (f) If a key usage extension is present in the CRL issuer's |
| // certificate, verify that the cRLSign bit is set. |
| if (issuer_cert->has_key_usage() && |
| !issuer_cert->key_usage().AssertsBit(KEY_USAGE_BIT_CRL_SIGN)) { |
| continue; |
| } |
| |
| // 6.3.3 (g) Validate the signature on the complete CRL using the public |
| // key validated in step (f). |
| if (!VerifySignedData(*signature_algorithm, tbs_cert_list_tlv, |
| signature_value, issuer_cert->tbs().spki_tlv, |
| /*cache=*/nullptr)) { |
| continue; |
| } |
| |
| // 6.3.3 (h,i) skipped. This implementation does not support delta CRLs. |
| |
| // 6.3.3 (j) If (cert_status is UNREVOKED), then search for the |
| // certificate on the complete CRL. If an entry is found that |
| // matches the certificate issuer and serial number as described |
| // in Section 5.3.3, then set the cert_status variable to the |
| // indicated reason as described in step (i). |
| // |
| // CRL is valid and covers |target_cert|, check if |target_cert| is present |
| // in the revokedCertificates sequence. |
| return GetCRLStatusForCert(target_cert->tbs().serial_number, |
| tbs_cert_list.version, |
| tbs_cert_list.revoked_certificates_tlv); |
| |
| // 6.3.3 (k,l) skipped. This implementation does not support reason codes. |
| } |
| |
| // Did not find the issuer & signer of |raw_crl| in |valid_chain|. |
| return CRLRevocationStatus::UNKNOWN; |
| } |
| |
| } // namespace net |
