// Copyright 2015 The Chromium Authors

//

// 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

//

//     https://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 <algorithm>

#include "certificate_policies.h"

#include <openssl/base.h>

#include "cert_error_params.h"

#include "cert_errors.h"

#include "input.h"

#include "parse_values.h"

#include "parser.h"

BSSL_NAMESPACE_BEGIN

namespace {

// ---------------------------------------------------------------

// Errors

// ---------------------------------------------------------------

DEFINE_CERT_ERROR_ID(kPolicyQualifiersEmptySequence,

                     "The policy qualifiers SEQUENCE is empty");

DEFINE_CERT_ERROR_ID(kUnknownPolicyQualifierOid,

                     "Unknown policy qualifier OID (not CPS or User Notice)");

DEFINE_CERT_ERROR_ID(kPoliciesEmptySequence, "Policies is an empty SEQUENCE");

DEFINE_CERT_ERROR_ID(kPoliciesDuplicateOid, "Policies contains duplicate OIDs");

DEFINE_CERT_ERROR_ID(kPolicyInformationTrailingData,

                     "PolicyInformation has trailing data");

DEFINE_CERT_ERROR_ID(kFailedParsingPolicyQualifiers,

                     "Failed parsing policy qualifiers");

DEFINE_CERT_ERROR_ID(kMissingQualifier,

                     "PolicyQualifierInfo is missing qualifier");

DEFINE_CERT_ERROR_ID(kPolicyQualifierInfoTrailingData,

                     "PolicyQualifierInfo has trailing data");

// Minimally parse policyQualifiers, storing in `policy_qualifiers` if non-null.

// If a policy qualifier other than User Notice/CPS is present, parsing

// will fail if `restrict_to_known_qualifiers` was set to true.

bool ParsePolicyQualifiers(bool restrict_to_known_qualifiers,

                           der::Parser *policy_qualifiers_sequence_parser,

                           std::vector<PolicyQualifierInfo> *policy_qualifiers,

                           CertErrors *errors) {

  BSSL_CHECK(errors);

  // If it is present, the policyQualifiers sequence should have at least 1

  // element.

  //

  //      policyQualifiers   SEQUENCE SIZE (1..MAX) OF

  //                              PolicyQualifierInfo OPTIONAL }

  if (!policy_qualifiers_sequence_parser->HasMore()) {

    errors->AddError(kPolicyQualifiersEmptySequence);

    return false;

  }

  while (policy_qualifiers_sequence_parser->HasMore()) {

    // PolicyQualifierInfo ::= SEQUENCE {

    der::Parser policy_information_parser;

    if (!policy_qualifiers_sequence_parser->ReadSequence(

            &policy_information_parser)) {

      return false;

    }

    //      policyQualifierId  PolicyQualifierId,

    der::Input qualifier_oid;

    if (!policy_information_parser.ReadTag(CBS_ASN1_OBJECT, &qualifier_oid)) {

      return false;

    }

    if (restrict_to_known_qualifiers &&

        qualifier_oid != der::Input(kCpsPointerId) &&

        qualifier_oid != der::Input(kUserNoticeId)) {

      errors->AddError(kUnknownPolicyQualifierOid,

                       CreateCertErrorParams1Der("oid", qualifier_oid));

      return false;

    }

    //      qualifier          ANY DEFINED BY policyQualifierId }

    der::Input qualifier_tlv;

    if (!policy_information_parser.ReadRawTLV(&qualifier_tlv)) {

      errors->AddError(kMissingQualifier);

      return false;

    }

    // Should not have trailing data after qualifier.

    if (policy_information_parser.HasMore()) {

      errors->AddError(kPolicyQualifierInfoTrailingData);

      return false;

    }

    if (policy_qualifiers) {

      policy_qualifiers->push_back({qualifier_oid, qualifier_tlv});

    }

  }

  return true;

}

// RFC 5280 section 4.2.1.4.  Certificate Policies:

//

// certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

//

// PolicyInformation ::= SEQUENCE {

//      policyIdentifier   CertPolicyId,

//      policyQualifiers   SEQUENCE SIZE (1..MAX) OF

//                              PolicyQualifierInfo OPTIONAL }

//

// CertPolicyId ::= OBJECT IDENTIFIER

//

// PolicyQualifierInfo ::= SEQUENCE {

//      policyQualifierId  PolicyQualifierId,

//      qualifier          ANY DEFINED BY policyQualifierId }

//

// PolicyQualifierId ::= OBJECT IDENTIFIER ( id-qt-cps | id-qt-unotice )

//

// Qualifier ::= CHOICE {

//      cPSuri           CPSuri,

//      userNotice       UserNotice }

//

// CPSuri ::= IA5String

//

// UserNotice ::= SEQUENCE {

//      noticeRef        NoticeReference OPTIONAL,

//      explicitText     DisplayText OPTIONAL }

//

// NoticeReference ::= SEQUENCE {

//      organization     DisplayText,

//      noticeNumbers    SEQUENCE OF INTEGER }

//

// DisplayText ::= CHOICE {

//      ia5String        IA5String      (SIZE (1..200)),

//      visibleString    VisibleString  (SIZE (1..200)),

//      bmpString        BMPString      (SIZE (1..200)),

//      utf8String       UTF8String     (SIZE (1..200)) }

bool ParseCertificatePoliciesExtensionImpl(

    der::Input extension_value, bool fail_parsing_unknown_qualifier_oids,

    std::vector<der::Input> *policy_oids,

    std::vector<PolicyInformation> *policy_informations, CertErrors *errors) {

  BSSL_CHECK(policy_oids);

  BSSL_CHECK(errors);

  // certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

  der::Parser extension_parser(extension_value);

  der::Parser policies_sequence_parser;

  if (!extension_parser.ReadSequence(&policies_sequence_parser)) {

    return false;

  }

  // Should not have trailing data after certificatePolicies sequence.

  if (extension_parser.HasMore()) {

    return false;

  }

  // The certificatePolicies sequence should have at least 1 element.

  if (!policies_sequence_parser.HasMore()) {

    errors->AddError(kPoliciesEmptySequence);

    return false;

  }

  policy_oids->clear();

  if (policy_informations) {

    policy_informations->clear();

  }

  while (policies_sequence_parser.HasMore()) {

    // PolicyInformation ::= SEQUENCE {

    der::Parser policy_information_parser;

    if (!policies_sequence_parser.ReadSequence(&policy_information_parser)) {

      return false;

    }

    //      policyIdentifier   CertPolicyId,

    der::Input policy_oid;

    if (!policy_information_parser.ReadTag(CBS_ASN1_OBJECT, &policy_oid)) {

      return false;

    }

    policy_oids->push_back(policy_oid);

    std::vector<PolicyQualifierInfo> *policy_qualifiers = nullptr;

    if (policy_informations) {

      policy_informations->emplace_back();

      policy_informations->back().policy_oid = policy_oid;

      policy_qualifiers = &policy_informations->back().policy_qualifiers;

    }

    if (!policy_information_parser.HasMore()) {

      continue;

    }

    //      policyQualifiers   SEQUENCE SIZE (1..MAX) OF

    //                              PolicyQualifierInfo OPTIONAL }

    der::Parser policy_qualifiers_sequence_parser;

    if (!policy_information_parser.ReadSequence(

            &policy_qualifiers_sequence_parser)) {

      return false;

    }

    // Should not have trailing data after policyQualifiers sequence.

    if (policy_information_parser.HasMore()) {

      errors->AddError(kPolicyInformationTrailingData);

      return false;

    }

    // RFC 5280 section 4.2.1.4: When qualifiers are used with the special

    // policy anyPolicy, they MUST be limited to the qualifiers identified in

    // this section.

    if (!ParsePolicyQualifiers(fail_parsing_unknown_qualifier_oids ||

                                   policy_oid == der::Input(kAnyPolicyOid),

                               &policy_qualifiers_sequence_parser,

                               policy_qualifiers, errors)) {

      errors->AddError(kFailedParsingPolicyQualifiers);

      return false;

    }

  }

  // RFC 5280 section 4.2.1.4: A certificate policy OID MUST NOT appear more

  // than once in a certificate policies extension.

  std::sort(policy_oids->begin(), policy_oids->end());

  auto dupe_policy_iter =

      std::adjacent_find(policy_oids->begin(), policy_oids->end());

  if (dupe_policy_iter != policy_oids->end()) {

    errors->AddError(kPoliciesDuplicateOid,

                     CreateCertErrorParams1Der("oid", *dupe_policy_iter));

    return false;

  }

  return true;

}

}  // namespace

bool ParseCertificatePoliciesExtension(der::Input extension_value,

                                       std::vector<PolicyInformation> *policies,

                                       CertErrors *errors) {

  std::vector<der::Input> unused_policy_oids;

  return ParseCertificatePoliciesExtensionImpl(

      extension_value, /*fail_parsing_unknown_qualifier_oids=*/false,

      &unused_policy_oids, policies, errors);

}

bool ParseCertificatePoliciesExtensionOids(

    der::Input extension_value, bool fail_parsing_unknown_qualifier_oids,

    std::vector<der::Input> *policy_oids, CertErrors *errors) {

  return ParseCertificatePoliciesExtensionImpl(

      extension_value, fail_parsing_unknown_qualifier_oids, policy_oids,

      nullptr, errors);

}

// From RFC 5280:

//

//   PolicyConstraints ::= SEQUENCE {

//        requireExplicitPolicy           [0] SkipCerts OPTIONAL,

//        inhibitPolicyMapping            [1] SkipCerts OPTIONAL }

//

//   SkipCerts ::= INTEGER (0..MAX)

bool ParsePolicyConstraints(der::Input policy_constraints_tlv,

                            ParsedPolicyConstraints *out) {

  der::Parser parser(policy_constraints_tlv);

  //   PolicyConstraints ::= SEQUENCE {

  der::Parser sequence_parser;

  if (!parser.ReadSequence(&sequence_parser)) {

    return false;

  }

  // RFC 5280 prohibits CAs from issuing PolicyConstraints as an empty sequence:

  //

  //   Conforming CAs MUST NOT issue certificates where policy constraints

  //   is an empty sequence.  That is, either the inhibitPolicyMapping field

  //   or the requireExplicitPolicy field MUST be present.  The behavior of

  //   clients that encounter an empty policy constraints field is not

  //   addressed in this profile.

  if (!sequence_parser.HasMore()) {

    return false;

  }

  std::optional<der::Input> require_value;

  if (!sequence_parser.ReadOptionalTag(CBS_ASN1_CONTEXT_SPECIFIC | 0,

                                       &require_value)) {

    return false;

  }

  if (require_value) {

    uint8_t require_explicit_policy;

    if (!ParseUint8(require_value.value(), &require_explicit_policy)) {

      // TODO(eroman): Surface reason for failure if length was longer than

      // uint8.

      return false;

    }

    out->require_explicit_policy = require_explicit_policy;

  }

  std::optional<der::Input> inhibit_value;

  if (!sequence_parser.ReadOptionalTag(CBS_ASN1_CONTEXT_SPECIFIC | 1,

                                       &inhibit_value)) {

    return false;

  }

  if (inhibit_value) {

    uint8_t inhibit_policy_mapping;

    if (!ParseUint8(inhibit_value.value(), &inhibit_policy_mapping)) {

      // TODO(eroman): Surface reason for failure if length was longer than

      // uint8.

      return false;

    }

    out->inhibit_policy_mapping = inhibit_policy_mapping;

  }

  // There should be no remaining data.

  if (sequence_parser.HasMore() || parser.HasMore()) {

    return false;

  }

  return true;

}

// From RFC 5280:

//

//   InhibitAnyPolicy ::= SkipCerts

//

//   SkipCerts ::= INTEGER (0..MAX)

std::optional<uint8_t> ParseInhibitAnyPolicy(

    der::Input inhibit_any_policy_tlv) {

  der::Parser parser(inhibit_any_policy_tlv);

  std::optional<uint8_t> num_certs = std::make_optional<uint8_t>();

  // TODO(eroman): Surface reason for failure if length was longer than uint8.

  if (!parser.ReadUint8(&num_certs.value())) {

    return std::nullopt;

  }

  // There should be no remaining data.

  if (parser.HasMore()) {

    return std::nullopt;

  }

  return num_certs;

}

// From RFC 5280:

//

//   PolicyMappings ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {

//        issuerDomainPolicy      CertPolicyId,

//        subjectDomainPolicy     CertPolicyId }

bool ParsePolicyMappings(der::Input policy_mappings_tlv,

                         std::vector<ParsedPolicyMapping> *mappings) {

  mappings->clear();

  der::Parser parser(policy_mappings_tlv);

  //   PolicyMappings ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE {

  der::Parser sequence_parser;

  if (!parser.ReadSequence(&sequence_parser)) {

    return false;

  }

  // Must be at least 1 mapping.

  if (!sequence_parser.HasMore()) {

    return false;

  }

  while (sequence_parser.HasMore()) {

    der::Parser mapping_parser;

    if (!sequence_parser.ReadSequence(&mapping_parser)) {

      return false;

    }

    ParsedPolicyMapping mapping;

    if (!mapping_parser.ReadTag(CBS_ASN1_OBJECT,

                                &mapping.issuer_domain_policy)) {

      return false;

    }

    if (!mapping_parser.ReadTag(CBS_ASN1_OBJECT,

                                &mapping.subject_domain_policy)) {

      return false;

    }

    // There shouldn't be extra unconsumed data.

    if (mapping_parser.HasMore()) {

      return false;

    }

    mappings->push_back(mapping);

  }

  // There shouldn't be extra unconsumed data.

  if (parser.HasMore()) {

    return false;

  }

  return true;

}

BSSL_NAMESPACE_END