| // Copyright 2015 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "parse_certificate.h" |
| |
| #include <optional> |
| #include <utility> |
| |
| #include <openssl/base.h> |
| #include <openssl/bytestring.h> |
| |
| #include "cert_error_params.h" |
| #include "cert_errors.h" |
| #include "general_names.h" |
| #include "input.h" |
| #include "parse_values.h" |
| #include "parser.h" |
| #include "string_util.h" |
| |
| namespace bssl { |
| |
| namespace { |
| |
| DEFINE_CERT_ERROR_ID(kCertificateNotSequence, |
| "Failed parsing Certificate SEQUENCE"); |
| DEFINE_CERT_ERROR_ID(kUnconsumedDataInsideCertificateSequence, |
| "Unconsumed data inside Certificate SEQUENCE"); |
| DEFINE_CERT_ERROR_ID(kUnconsumedDataAfterCertificateSequence, |
| "Unconsumed data after Certificate SEQUENCE"); |
| DEFINE_CERT_ERROR_ID(kTbsCertificateNotSequence, |
| "Couldn't read tbsCertificate as SEQUENCE"); |
| DEFINE_CERT_ERROR_ID( |
| kSignatureAlgorithmNotSequence, |
| "Couldn't read Certificate.signatureAlgorithm as SEQUENCE"); |
| DEFINE_CERT_ERROR_ID(kSignatureValueNotBitString, |
| "Couldn't read Certificate.signatureValue as BIT STRING"); |
| DEFINE_CERT_ERROR_ID(kUnconsumedDataInsideTbsCertificateSequence, |
| "Unconsumed data inside TBSCertificate"); |
| DEFINE_CERT_ERROR_ID(kTbsNotSequence, "Failed parsing TBSCertificate SEQUENCE"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingVersion, "Failed reading version"); |
| DEFINE_CERT_ERROR_ID(kFailedParsingVersion, "Failed parsing version"); |
| DEFINE_CERT_ERROR_ID(kVersionExplicitlyV1, |
| "Version explicitly V1 (should be omitted)"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingSerialNumber, "Failed reading serialNumber"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingSignatureValue, "Failed reading signature"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingIssuer, "Failed reading issuer"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingValidity, "Failed reading validity"); |
| DEFINE_CERT_ERROR_ID(kFailedParsingValidity, "Failed parsing validity"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingSubject, "Failed reading subject"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingSpki, "Failed reading subjectPublicKeyInfo"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingIssuerUniqueId, |
| "Failed reading issuerUniqueId"); |
| DEFINE_CERT_ERROR_ID(kFailedParsingIssuerUniqueId, |
| "Failed parsing issuerUniqueId"); |
| DEFINE_CERT_ERROR_ID( |
| kIssuerUniqueIdNotExpected, |
| "Unexpected issuerUniqueId (must be V2 or V3 certificate)"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingSubjectUniqueId, |
| "Failed reading subjectUniqueId"); |
| DEFINE_CERT_ERROR_ID(kFailedParsingSubjectUniqueId, |
| "Failed parsing subjectUniqueId"); |
| DEFINE_CERT_ERROR_ID( |
| kSubjectUniqueIdNotExpected, |
| "Unexpected subjectUniqueId (must be V2 or V3 certificate)"); |
| DEFINE_CERT_ERROR_ID(kFailedReadingExtensions, |
| "Failed reading extensions SEQUENCE"); |
| DEFINE_CERT_ERROR_ID(kUnexpectedExtensions, |
| "Unexpected extensions (must be V3 certificate)"); |
| DEFINE_CERT_ERROR_ID(kSerialNumberIsNegative, "Serial number is negative"); |
| DEFINE_CERT_ERROR_ID(kSerialNumberIsZero, "Serial number is zero"); |
| DEFINE_CERT_ERROR_ID(kSerialNumberLengthOver20, |
| "Serial number is longer than 20 octets"); |
| DEFINE_CERT_ERROR_ID(kSerialNumberNotValidInteger, |
| "Serial number is not a valid INTEGER"); |
| |
| // Returns true if |input| is a SEQUENCE and nothing else. |
| [[nodiscard]] bool IsSequenceTLV(der::Input input) { |
| der::Parser parser(input); |
| der::Parser unused_sequence_parser; |
| if (!parser.ReadSequence(&unused_sequence_parser)) { |
| return false; |
| } |
| // Should by a single SEQUENCE by definition of the function. |
| return !parser.HasMore(); |
| } |
| |
| // Reads a SEQUENCE from |parser| and writes the full tag-length-value into |
| // |out|. On failure |parser| may or may not have been advanced. |
| [[nodiscard]] bool ReadSequenceTLV(der::Parser *parser, der::Input *out) { |
| return parser->ReadRawTLV(out) && IsSequenceTLV(*out); |
| } |
| |
| // Parses a Version according to RFC 5280: |
| // |
| // Version ::= INTEGER { v1(0), v2(1), v3(2) } |
| // |
| // No value other that v1, v2, or v3 is allowed (and if given will fail). RFC |
| // 5280 minimally requires the handling of v3 (and overwhelmingly these are the |
| // certificate versions in use today): |
| // |
| // Implementations SHOULD be prepared to accept any version certificate. |
| // At a minimum, conforming implementations MUST recognize version 3 |
| // certificates. |
| [[nodiscard]] bool ParseVersion(der::Input in, CertificateVersion *version) { |
| der::Parser parser(in); |
| uint64_t version64; |
| if (!parser.ReadUint64(&version64)) { |
| return false; |
| } |
| |
| switch (version64) { |
| case 0: |
| *version = CertificateVersion::V1; |
| break; |
| case 1: |
| *version = CertificateVersion::V2; |
| break; |
| case 2: |
| *version = CertificateVersion::V3; |
| break; |
| default: |
| // Don't allow any other version identifier. |
| return false; |
| } |
| |
| // By definition the input to this function was a single INTEGER, so there |
| // shouldn't be anything else after it. |
| return !parser.HasMore(); |
| } |
| |
| // Returns true if every bit in |bits| is zero (including empty). |
| [[nodiscard]] bool BitStringIsAllZeros(const der::BitString &bits) { |
| // Note that it is OK to read from the unused bits, since BitString parsing |
| // guarantees they are all zero. |
| for (uint8_t b : bits.bytes()) { |
| if (b != 0) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| // Parses a DistributionPointName. |
| // |
| // From RFC 5280: |
| // |
| // DistributionPointName ::= CHOICE { |
| // fullName [0] GeneralNames, |
| // nameRelativeToCRLIssuer [1] RelativeDistinguishedName } |
| bool ParseDistributionPointName(der::Input dp_name, |
| ParsedDistributionPoint *distribution_point) { |
| der::Parser parser(dp_name); |
| std::optional<der::Input> der_full_name; |
| if (!parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0, |
| &der_full_name)) { |
| return false; |
| } |
| if (der_full_name) { |
| // TODO(mattm): surface the CertErrors. |
| CertErrors errors; |
| distribution_point->distribution_point_fullname = |
| GeneralNames::CreateFromValue(*der_full_name, &errors); |
| if (!distribution_point->distribution_point_fullname) { |
| return false; |
| } |
| return !parser.HasMore(); |
| } |
| |
| if (!parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 1, |
| &distribution_point |
| ->distribution_point_name_relative_to_crl_issuer)) { |
| return false; |
| } |
| if (distribution_point->distribution_point_name_relative_to_crl_issuer) { |
| return !parser.HasMore(); |
| } |
| |
| // The CHOICE must contain either fullName or nameRelativeToCRLIssuer. |
| return false; |
| } |
| |
| // RFC 5280, section 4.2.1.13. |
| // |
| // DistributionPoint ::= SEQUENCE { |
| // distributionPoint [0] DistributionPointName OPTIONAL, |
| // reasons [1] ReasonFlags OPTIONAL, |
| // cRLIssuer [2] GeneralNames OPTIONAL } |
| bool ParseAndAddDistributionPoint( |
| der::Parser *parser, |
| std::vector<ParsedDistributionPoint> *distribution_points) { |
| ParsedDistributionPoint distribution_point; |
| |
| // DistributionPoint ::= SEQUENCE { |
| der::Parser distrib_point_parser; |
| if (!parser->ReadSequence(&distrib_point_parser)) { |
| return false; |
| } |
| |
| // distributionPoint [0] DistributionPointName OPTIONAL, |
| std::optional<der::Input> distribution_point_name; |
| if (!distrib_point_parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0, |
| &distribution_point_name)) { |
| return false; |
| } |
| |
| if (distribution_point_name && |
| !ParseDistributionPointName(*distribution_point_name, |
| &distribution_point)) { |
| return false; |
| } |
| |
| // reasons [1] ReasonFlags OPTIONAL, |
| if (!distrib_point_parser.ReadOptionalTag(CBS_ASN1_CONTEXT_SPECIFIC | 1, |
| &distribution_point.reasons)) { |
| return false; |
| } |
| |
| // cRLIssuer [2] GeneralNames OPTIONAL } |
| if (!distrib_point_parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 2, |
| &distribution_point.crl_issuer)) { |
| return false; |
| } |
| // TODO(eroman): Parse "cRLIssuer"? |
| |
| // RFC 5280, section 4.2.1.13: |
| // either distributionPoint or cRLIssuer MUST be present. |
| if (!distribution_point_name && !distribution_point.crl_issuer) { |
| return false; |
| } |
| |
| if (distrib_point_parser.HasMore()) { |
| return false; |
| } |
| |
| distribution_points->push_back(std::move(distribution_point)); |
| return true; |
| } |
| |
| } // namespace |
| |
| ParsedTbsCertificate::ParsedTbsCertificate() = default; |
| |
| ParsedTbsCertificate::ParsedTbsCertificate(ParsedTbsCertificate &&other) = |
| default; |
| |
| ParsedTbsCertificate::~ParsedTbsCertificate() = default; |
| |
| bool VerifySerialNumber(der::Input value, bool warnings_only, |
| CertErrors *errors) { |
| // If |warnings_only| was set to true, the exact same errors will be logged, |
| // only they will be logged with a lower severity (warning rather than error). |
| CertError::Severity error_severity = |
| warnings_only ? CertError::SEVERITY_WARNING : CertError::SEVERITY_HIGH; |
| |
| bool negative; |
| if (!der::IsValidInteger(value, &negative)) { |
| errors->Add(error_severity, kSerialNumberNotValidInteger, nullptr); |
| return false; |
| } |
| |
| // RFC 5280 section 4.1.2.2: |
| // |
| // 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. |
| if (negative) { |
| errors->AddWarning(kSerialNumberIsNegative); |
| } |
| if (value.size() == 1 && value[0] == 0) { |
| errors->AddWarning(kSerialNumberIsZero); |
| } |
| |
| // RFC 5280 section 4.1.2.2: |
| // |
| // Certificate users MUST be able to handle serialNumber values up to 20 |
| // octets. Conforming CAs MUST NOT use serialNumber values longer than 20 |
| // octets. |
| if (value.size() > 20) { |
| errors->Add(error_severity, kSerialNumberLengthOver20, |
| CreateCertErrorParams1SizeT("length", value.size())); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool ReadUTCOrGeneralizedTime(der::Parser *parser, der::GeneralizedTime *out) { |
| der::Input value; |
| CBS_ASN1_TAG tag; |
| |
| if (!parser->ReadTagAndValue(&tag, &value)) { |
| return false; |
| } |
| |
| if (tag == CBS_ASN1_UTCTIME) { |
| return der::ParseUTCTime(value, out); |
| } |
| |
| if (tag == CBS_ASN1_GENERALIZEDTIME) { |
| return der::ParseGeneralizedTime(value, out); |
| } |
| |
| // Unrecognized tag. |
| return false; |
| } |
| |
| bool ParseValidity(der::Input validity_tlv, der::GeneralizedTime *not_before, |
| der::GeneralizedTime *not_after) { |
| der::Parser parser(validity_tlv); |
| |
| // Validity ::= SEQUENCE { |
| der::Parser validity_parser; |
| if (!parser.ReadSequence(&validity_parser)) { |
| return false; |
| } |
| |
| // notBefore Time, |
| if (!ReadUTCOrGeneralizedTime(&validity_parser, not_before)) { |
| return false; |
| } |
| |
| // notAfter Time } |
| if (!ReadUTCOrGeneralizedTime(&validity_parser, not_after)) { |
| return false; |
| } |
| |
| // By definition the input was a single Validity sequence, so there shouldn't |
| // be unconsumed data. |
| if (parser.HasMore()) { |
| return false; |
| } |
| |
| // The Validity type does not have an extension point. |
| if (validity_parser.HasMore()) { |
| return false; |
| } |
| |
| // Note that RFC 5280 doesn't require notBefore to be <= |
| // notAfter, so that will not be considered a "parsing" error here. Instead it |
| // will be considered an expired certificate later when testing against the |
| // current timestamp. |
| return true; |
| } |
| |
| bool ParseCertificate(der::Input certificate_tlv, |
| der::Input *out_tbs_certificate_tlv, |
| der::Input *out_signature_algorithm_tlv, |
| der::BitString *out_signature_value, |
| CertErrors *out_errors) { |
| // |out_errors| is optional. But ensure it is non-null for the remainder of |
| // this function. |
| CertErrors unused_errors; |
| if (!out_errors) { |
| out_errors = &unused_errors; |
| } |
| |
| der::Parser parser(certificate_tlv); |
| |
| // Certificate ::= SEQUENCE { |
| der::Parser certificate_parser; |
| if (!parser.ReadSequence(&certificate_parser)) { |
| out_errors->AddError(kCertificateNotSequence); |
| return false; |
| } |
| |
| // tbsCertificate TBSCertificate, |
| if (!ReadSequenceTLV(&certificate_parser, out_tbs_certificate_tlv)) { |
| out_errors->AddError(kTbsCertificateNotSequence); |
| return false; |
| } |
| |
| // signatureAlgorithm AlgorithmIdentifier, |
| if (!ReadSequenceTLV(&certificate_parser, out_signature_algorithm_tlv)) { |
| out_errors->AddError(kSignatureAlgorithmNotSequence); |
| return false; |
| } |
| |
| // signatureValue BIT STRING } |
| std::optional<der::BitString> signature_value = |
| certificate_parser.ReadBitString(); |
| if (!signature_value) { |
| out_errors->AddError(kSignatureValueNotBitString); |
| return false; |
| } |
| *out_signature_value = signature_value.value(); |
| |
| // There isn't an extension point at the end of Certificate. |
| if (certificate_parser.HasMore()) { |
| out_errors->AddError(kUnconsumedDataInsideCertificateSequence); |
| return false; |
| } |
| |
| // By definition the input was a single Certificate, so there shouldn't be |
| // unconsumed data. |
| if (parser.HasMore()) { |
| out_errors->AddError(kUnconsumedDataAfterCertificateSequence); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| // From RFC 5280 section 4.1: |
| // |
| // 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 |
| // } |
| bool ParseTbsCertificate(der::Input tbs_tlv, |
| const ParseCertificateOptions &options, |
| ParsedTbsCertificate *out, CertErrors *errors) { |
| // The rest of this function assumes that |errors| is non-null. |
| CertErrors unused_errors; |
| if (!errors) { |
| errors = &unused_errors; |
| } |
| |
| // TODO(crbug.com/634443): Add useful error information to |errors|. |
| |
| der::Parser parser(tbs_tlv); |
| |
| // TBSCertificate ::= SEQUENCE { |
| der::Parser tbs_parser; |
| if (!parser.ReadSequence(&tbs_parser)) { |
| errors->AddError(kTbsNotSequence); |
| return false; |
| } |
| |
| // version [0] EXPLICIT Version DEFAULT v1, |
| std::optional<der::Input> version; |
| if (!tbs_parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 0, &version)) { |
| errors->AddError(kFailedReadingVersion); |
| return false; |
| } |
| if (version) { |
| if (!ParseVersion(version.value(), &out->version)) { |
| errors->AddError(kFailedParsingVersion); |
| return false; |
| } |
| if (out->version == CertificateVersion::V1) { |
| errors->AddError(kVersionExplicitlyV1); |
| // The correct way to specify v1 is to omit the version field since v1 is |
| // the DEFAULT. |
| return false; |
| } |
| } else { |
| out->version = CertificateVersion::V1; |
| } |
| |
| // serialNumber CertificateSerialNumber, |
| if (!tbs_parser.ReadTag(CBS_ASN1_INTEGER, &out->serial_number)) { |
| errors->AddError(kFailedReadingSerialNumber); |
| return false; |
| } |
| if (!VerifySerialNumber(out->serial_number, |
| options.allow_invalid_serial_numbers, errors)) { |
| // Invalid serial numbers are only considered fatal failures if |
| // |!allow_invalid_serial_numbers|. |
| if (!options.allow_invalid_serial_numbers) { |
| return false; |
| } |
| } |
| |
| // signature AlgorithmIdentifier, |
| if (!ReadSequenceTLV(&tbs_parser, &out->signature_algorithm_tlv)) { |
| errors->AddError(kFailedReadingSignatureValue); |
| return false; |
| } |
| |
| // issuer Name, |
| if (!ReadSequenceTLV(&tbs_parser, &out->issuer_tlv)) { |
| errors->AddError(kFailedReadingIssuer); |
| return false; |
| } |
| |
| // validity Validity, |
| der::Input validity_tlv; |
| if (!tbs_parser.ReadRawTLV(&validity_tlv)) { |
| errors->AddError(kFailedReadingValidity); |
| return false; |
| } |
| if (!ParseValidity(validity_tlv, &out->validity_not_before, |
| &out->validity_not_after)) { |
| errors->AddError(kFailedParsingValidity); |
| return false; |
| } |
| |
| // subject Name, |
| if (!ReadSequenceTLV(&tbs_parser, &out->subject_tlv)) { |
| errors->AddError(kFailedReadingSubject); |
| return false; |
| } |
| |
| // subjectPublicKeyInfo SubjectPublicKeyInfo, |
| if (!ReadSequenceTLV(&tbs_parser, &out->spki_tlv)) { |
| errors->AddError(kFailedReadingSpki); |
| return false; |
| } |
| |
| // issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL, |
| // -- If present, version MUST be v2 or v3 |
| std::optional<der::Input> issuer_unique_id; |
| if (!tbs_parser.ReadOptionalTag(CBS_ASN1_CONTEXT_SPECIFIC | 1, |
| &issuer_unique_id)) { |
| errors->AddError(kFailedReadingIssuerUniqueId); |
| return false; |
| } |
| if (issuer_unique_id) { |
| out->issuer_unique_id = der::ParseBitString(issuer_unique_id.value()); |
| if (!out->issuer_unique_id) { |
| errors->AddError(kFailedParsingIssuerUniqueId); |
| return false; |
| } |
| if (out->version != CertificateVersion::V2 && |
| out->version != CertificateVersion::V3) { |
| errors->AddError(kIssuerUniqueIdNotExpected); |
| return false; |
| } |
| } |
| |
| // subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL, |
| // -- If present, version MUST be v2 or v3 |
| std::optional<der::Input> subject_unique_id; |
| if (!tbs_parser.ReadOptionalTag(CBS_ASN1_CONTEXT_SPECIFIC | 2, |
| &subject_unique_id)) { |
| errors->AddError(kFailedReadingSubjectUniqueId); |
| return false; |
| } |
| if (subject_unique_id) { |
| out->subject_unique_id = der::ParseBitString(subject_unique_id.value()); |
| if (!out->subject_unique_id) { |
| errors->AddError(kFailedParsingSubjectUniqueId); |
| return false; |
| } |
| if (out->version != CertificateVersion::V2 && |
| out->version != CertificateVersion::V3) { |
| errors->AddError(kSubjectUniqueIdNotExpected); |
| return false; |
| } |
| } |
| |
| // extensions [3] EXPLICIT Extensions OPTIONAL |
| // -- If present, version MUST be v3 |
| if (!tbs_parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 3, |
| &out->extensions_tlv)) { |
| errors->AddError(kFailedReadingExtensions); |
| return false; |
| } |
| if (out->extensions_tlv) { |
| // extensions_tlv must be a single element. Also check that it is a |
| // SEQUENCE. |
| if (!IsSequenceTLV(out->extensions_tlv.value())) { |
| errors->AddError(kFailedReadingExtensions); |
| return false; |
| } |
| if (out->version != CertificateVersion::V3) { |
| errors->AddError(kUnexpectedExtensions); |
| return false; |
| } |
| } |
| |
| // Note that there IS an extension point at the end of TBSCertificate |
| // (according to RFC 5912), so from that interpretation, unconsumed data would |
| // be allowed in |tbs_parser|. |
| // |
| // However because only v1, v2, and v3 certificates are supported by the |
| // parsing, there shouldn't be any subsequent data in those versions, so |
| // reject. |
| if (tbs_parser.HasMore()) { |
| errors->AddError(kUnconsumedDataInsideTbsCertificateSequence); |
| return false; |
| } |
| |
| // By definition the input was a single TBSCertificate, so there shouldn't be |
| // unconsumed data. |
| if (parser.HasMore()) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| // From RFC 5280: |
| // |
| // Extension ::= SEQUENCE { |
| // extnID OBJECT IDENTIFIER, |
| // critical BOOLEAN DEFAULT FALSE, |
| // extnValue OCTET STRING |
| // -- contains the DER encoding of an ASN.1 value |
| // -- corresponding to the extension type identified |
| // -- by extnID |
| // } |
| bool ParseExtension(der::Input extension_tlv, ParsedExtension *out) { |
| der::Parser parser(extension_tlv); |
| |
| // Extension ::= SEQUENCE { |
| der::Parser extension_parser; |
| if (!parser.ReadSequence(&extension_parser)) { |
| return false; |
| } |
| |
| // extnID OBJECT IDENTIFIER, |
| if (!extension_parser.ReadTag(CBS_ASN1_OBJECT, &out->oid)) { |
| return false; |
| } |
| |
| // critical BOOLEAN DEFAULT FALSE, |
| out->critical = false; |
| bool has_critical; |
| der::Input critical; |
| if (!extension_parser.ReadOptionalTag(CBS_ASN1_BOOLEAN, &critical, |
| &has_critical)) { |
| return false; |
| } |
| if (has_critical) { |
| if (!der::ParseBool(critical, &out->critical)) { |
| return false; |
| } |
| if (!out->critical) { |
| return false; // DER-encoding requires DEFAULT values be omitted. |
| } |
| } |
| |
| // extnValue OCTET STRING |
| if (!extension_parser.ReadTag(CBS_ASN1_OCTETSTRING, &out->value)) { |
| return false; |
| } |
| |
| // The Extension type does not have an extension point (everything goes in |
| // extnValue). |
| if (extension_parser.HasMore()) { |
| return false; |
| } |
| |
| // By definition the input was a single Extension sequence, so there shouldn't |
| // be unconsumed data. |
| if (parser.HasMore()) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| OPENSSL_EXPORT bool ParseExtensions( |
| der::Input extensions_tlv, |
| std::map<der::Input, ParsedExtension> *extensions) { |
| der::Parser parser(extensions_tlv); |
| |
| // Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension |
| der::Parser extensions_parser; |
| if (!parser.ReadSequence(&extensions_parser)) { |
| return false; |
| } |
| |
| // The Extensions SEQUENCE must contains at least 1 element (otherwise it |
| // should have been omitted). |
| if (!extensions_parser.HasMore()) { |
| return false; |
| } |
| |
| extensions->clear(); |
| |
| while (extensions_parser.HasMore()) { |
| ParsedExtension extension; |
| |
| der::Input extension_tlv; |
| if (!extensions_parser.ReadRawTLV(&extension_tlv)) { |
| return false; |
| } |
| |
| if (!ParseExtension(extension_tlv, &extension)) { |
| return false; |
| } |
| |
| bool is_duplicate = |
| !extensions->insert(std::make_pair(extension.oid, extension)).second; |
| |
| // RFC 5280 says that an extension should not appear more than once. |
| if (is_duplicate) { |
| return false; |
| } |
| } |
| |
| // By definition the input was a single Extensions sequence, so there |
| // shouldn't be unconsumed data. |
| if (parser.HasMore()) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| OPENSSL_EXPORT bool ConsumeExtension( |
| der::Input oid, |
| std::map<der::Input, ParsedExtension> *unconsumed_extensions, |
| ParsedExtension *extension) { |
| auto it = unconsumed_extensions->find(oid); |
| if (it == unconsumed_extensions->end()) { |
| return false; |
| } |
| |
| *extension = it->second; |
| unconsumed_extensions->erase(it); |
| return true; |
| } |
| |
| bool ParseBasicConstraints(der::Input basic_constraints_tlv, |
| ParsedBasicConstraints *out) { |
| der::Parser parser(basic_constraints_tlv); |
| |
| // BasicConstraints ::= SEQUENCE { |
| der::Parser sequence_parser; |
| if (!parser.ReadSequence(&sequence_parser)) { |
| return false; |
| } |
| |
| // cA BOOLEAN DEFAULT FALSE, |
| out->is_ca = false; |
| bool has_ca; |
| der::Input ca; |
| if (!sequence_parser.ReadOptionalTag(CBS_ASN1_BOOLEAN, &ca, &has_ca)) { |
| return false; |
| } |
| if (has_ca) { |
| if (!der::ParseBool(ca, &out->is_ca)) { |
| return false; |
| } |
| // TODO(eroman): Should reject if CA was set to false, since |
| // DER-encoding requires DEFAULT values be omitted. In |
| // practice however there are a lot of certificates that use |
| // the broken encoding. |
| } |
| |
| // pathLenConstraint INTEGER (0..MAX) OPTIONAL } |
| der::Input encoded_path_len; |
| if (!sequence_parser.ReadOptionalTag(CBS_ASN1_INTEGER, &encoded_path_len, |
| &out->has_path_len)) { |
| return false; |
| } |
| if (out->has_path_len) { |
| // TODO(eroman): Surface reason for failure if length was longer than uint8. |
| if (!der::ParseUint8(encoded_path_len, &out->path_len)) { |
| return false; |
| } |
| } else { |
| // Default initialize to 0 as a precaution. |
| out->path_len = 0; |
| } |
| |
| // There shouldn't be any unconsumed data in the extension. |
| if (sequence_parser.HasMore()) { |
| return false; |
| } |
| |
| // By definition the input was a single BasicConstraints sequence, so there |
| // shouldn't be unconsumed data. |
| if (parser.HasMore()) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| // TODO(crbug.com/1314019): return std::optional<BitString> when converting |
| // has_key_usage_ and key_usage_ into single std::optional field. |
| bool ParseKeyUsage(der::Input key_usage_tlv, der::BitString *key_usage) { |
| der::Parser parser(key_usage_tlv); |
| std::optional<der::BitString> key_usage_internal = parser.ReadBitString(); |
| if (!key_usage_internal) { |
| return false; |
| } |
| |
| // By definition the input was a single BIT STRING. |
| if (parser.HasMore()) { |
| return false; |
| } |
| |
| // RFC 5280 section 4.2.1.3: |
| // |
| // When the keyUsage extension appears in a certificate, at least |
| // one of the bits MUST be set to 1. |
| if (BitStringIsAllZeros(key_usage_internal.value())) { |
| return false; |
| } |
| |
| *key_usage = key_usage_internal.value(); |
| return true; |
| } |
| |
| bool ParseAuthorityInfoAccess( |
| der::Input authority_info_access_tlv, |
| std::vector<AuthorityInfoAccessDescription> *out_access_descriptions) { |
| der::Parser parser(authority_info_access_tlv); |
| |
| out_access_descriptions->clear(); |
| |
| // AuthorityInfoAccessSyntax ::= |
| // SEQUENCE SIZE (1..MAX) OF AccessDescription |
| der::Parser sequence_parser; |
| if (!parser.ReadSequence(&sequence_parser)) { |
| return false; |
| } |
| if (!sequence_parser.HasMore()) { |
| return false; |
| } |
| |
| while (sequence_parser.HasMore()) { |
| AuthorityInfoAccessDescription access_description; |
| |
| // AccessDescription ::= SEQUENCE { |
| der::Parser access_description_sequence_parser; |
| if (!sequence_parser.ReadSequence(&access_description_sequence_parser)) { |
| return false; |
| } |
| |
| // accessMethod OBJECT IDENTIFIER, |
| if (!access_description_sequence_parser.ReadTag( |
| CBS_ASN1_OBJECT, &access_description.access_method_oid)) { |
| return false; |
| } |
| |
| // accessLocation GeneralName } |
| if (!access_description_sequence_parser.ReadRawTLV( |
| &access_description.access_location)) { |
| return false; |
| } |
| |
| if (access_description_sequence_parser.HasMore()) { |
| return false; |
| } |
| |
| out_access_descriptions->push_back(access_description); |
| } |
| |
| return true; |
| } |
| |
| bool ParseAuthorityInfoAccessURIs( |
| der::Input authority_info_access_tlv, |
| std::vector<std::string_view> *out_ca_issuers_uris, |
| std::vector<std::string_view> *out_ocsp_uris) { |
| std::vector<AuthorityInfoAccessDescription> access_descriptions; |
| if (!ParseAuthorityInfoAccess(authority_info_access_tlv, |
| &access_descriptions)) { |
| return false; |
| } |
| |
| for (const auto &access_description : access_descriptions) { |
| der::Parser access_location_parser(access_description.access_location); |
| CBS_ASN1_TAG access_location_tag; |
| der::Input access_location_value; |
| if (!access_location_parser.ReadTagAndValue(&access_location_tag, |
| &access_location_value)) { |
| return false; |
| } |
| |
| // GeneralName ::= CHOICE { |
| if (access_location_tag == (CBS_ASN1_CONTEXT_SPECIFIC | 6)) { |
| // uniformResourceIdentifier [6] IA5String, |
| std::string_view uri = BytesAsStringView(access_location_value); |
| if (!bssl::string_util::IsAscii(uri)) { |
| return false; |
| } |
| |
| if (access_description.access_method_oid == der::Input(kAdCaIssuersOid)) { |
| out_ca_issuers_uris->push_back(uri); |
| } else if (access_description.access_method_oid == |
| der::Input(kAdOcspOid)) { |
| out_ocsp_uris->push_back(uri); |
| } |
| } |
| } |
| return true; |
| } |
| |
| ParsedDistributionPoint::ParsedDistributionPoint() = default; |
| ParsedDistributionPoint::ParsedDistributionPoint( |
| ParsedDistributionPoint &&other) = default; |
| ParsedDistributionPoint::~ParsedDistributionPoint() = default; |
| |
| bool ParseCrlDistributionPoints( |
| der::Input extension_value, |
| std::vector<ParsedDistributionPoint> *distribution_points) { |
| distribution_points->clear(); |
| |
| // RFC 5280, section 4.2.1.13. |
| // |
| // CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint |
| der::Parser extension_value_parser(extension_value); |
| der::Parser distribution_points_parser; |
| if (!extension_value_parser.ReadSequence(&distribution_points_parser)) { |
| return false; |
| } |
| if (extension_value_parser.HasMore()) { |
| return false; |
| } |
| |
| // Sequence must have a minimum of 1 item. |
| if (!distribution_points_parser.HasMore()) { |
| return false; |
| } |
| |
| while (distribution_points_parser.HasMore()) { |
| if (!ParseAndAddDistributionPoint(&distribution_points_parser, |
| distribution_points)) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| ParsedAuthorityKeyIdentifier::ParsedAuthorityKeyIdentifier() = default; |
| ParsedAuthorityKeyIdentifier::~ParsedAuthorityKeyIdentifier() = default; |
| ParsedAuthorityKeyIdentifier::ParsedAuthorityKeyIdentifier( |
| ParsedAuthorityKeyIdentifier &&other) = default; |
| ParsedAuthorityKeyIdentifier &ParsedAuthorityKeyIdentifier::operator=( |
| ParsedAuthorityKeyIdentifier &&other) = default; |
| |
| bool ParseAuthorityKeyIdentifier( |
| der::Input extension_value, |
| ParsedAuthorityKeyIdentifier *authority_key_identifier) { |
| // RFC 5280, section 4.2.1.1. |
| // AuthorityKeyIdentifier ::= SEQUENCE { |
| // keyIdentifier [0] KeyIdentifier OPTIONAL, |
| // authorityCertIssuer [1] GeneralNames OPTIONAL, |
| // authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL } |
| // |
| // KeyIdentifier ::= OCTET STRING |
| |
| der::Parser extension_value_parser(extension_value); |
| der::Parser aki_parser; |
| if (!extension_value_parser.ReadSequence(&aki_parser)) { |
| return false; |
| } |
| if (extension_value_parser.HasMore()) { |
| return false; |
| } |
| |
| // TODO(mattm): Should having an empty AuthorityKeyIdentifier SEQUENCE be an |
| // error? RFC 5280 doesn't explicitly say it. |
| |
| // keyIdentifier [0] KeyIdentifier OPTIONAL, |
| if (!aki_parser.ReadOptionalTag(CBS_ASN1_CONTEXT_SPECIFIC | 0, |
| &authority_key_identifier->key_identifier)) { |
| return false; |
| } |
| |
| // authorityCertIssuer [1] GeneralNames OPTIONAL, |
| if (!aki_parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | CBS_ASN1_CONSTRUCTED | 1, |
| &authority_key_identifier->authority_cert_issuer)) { |
| return false; |
| } |
| |
| // authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL } |
| if (!aki_parser.ReadOptionalTag( |
| CBS_ASN1_CONTEXT_SPECIFIC | 2, |
| &authority_key_identifier->authority_cert_serial_number)) { |
| return false; |
| } |
| |
| // -- authorityCertIssuer and authorityCertSerialNumber MUST both |
| // -- be present or both be absent |
| if (authority_key_identifier->authority_cert_issuer.has_value() != |
| authority_key_identifier->authority_cert_serial_number.has_value()) { |
| return false; |
| } |
| |
| // There shouldn't be any unconsumed data in the AuthorityKeyIdentifier |
| // SEQUENCE. |
| if (aki_parser.HasMore()) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool ParseSubjectKeyIdentifier(der::Input extension_value, |
| der::Input *subject_key_identifier) { |
| // SubjectKeyIdentifier ::= KeyIdentifier |
| // |
| // KeyIdentifier ::= OCTET STRING |
| der::Parser extension_value_parser(extension_value); |
| if (!extension_value_parser.ReadTag(CBS_ASN1_OCTETSTRING, |
| subject_key_identifier)) { |
| return false; |
| } |
| |
| // There shouldn't be any unconsumed data in the extension SEQUENCE. |
| if (extension_value_parser.HasMore()) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| } // namespace bssl |
