// Copyright 2017 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 "simple_path_builder_delegate.h"

#include <openssl/bn.h>
#include <openssl/bytestring.h>
#include <openssl/digest.h>
#include <openssl/ec.h>
#include <openssl/ec_key.h>
#include <openssl/evp.h>
#include <openssl/nid.h>
#include <openssl/pki/signature_verify_cache.h>
#include <openssl/rsa.h>

#include "cert_error_params.h"
#include "cert_errors.h"
#include "signature_algorithm.h"

BSSL_NAMESPACE_BEGIN

DEFINE_CERT_ERROR_ID(SimplePathBuilderDelegate::kRsaModulusTooSmall,
                     "RSA modulus too small");

namespace {

DEFINE_CERT_ERROR_ID(kUnacceptableCurveForEcdsa,
                     "Only P-256, P-384, P-521 are supported for ECDSA");

bool IsAcceptableCurveForEcdsa(int curve_nid) {
  switch (curve_nid) {
    case NID_X9_62_prime256v1:
    case NID_secp384r1:
    case NID_secp521r1:
      return true;
  }

  return false;
}

}  // namespace

SimplePathBuilderDelegate::SimplePathBuilderDelegate(
    size_t min_rsa_modulus_length_bits, DigestPolicy digest_policy)
    : min_rsa_modulus_length_bits_(min_rsa_modulus_length_bits),
      digest_policy_(digest_policy) {}

void SimplePathBuilderDelegate::CheckPathAfterVerification(
    const CertPathBuilder &path_builder, CertPathBuilderResultPath *path) {
  // Do nothing - consider all candidate paths valid.
}

bool SimplePathBuilderDelegate::IsDeadlineExpired() { return false; }

bool SimplePathBuilderDelegate::IsDebugLogEnabled() { return false; }

bool SimplePathBuilderDelegate::AcceptPreCertificates() { return false; }

std::optional<SimplePathBuilderDelegate::MTCCosigner>
SimplePathBuilderDelegate::GetMTCCosigner(Span<const uint8_t> cosigner_id) {
  return std::nullopt;
}

bool SimplePathBuilderDelegate::IsCosignatureVerificationResultAcceptable(
    const MTCAnchor *mtc_anchor,
    std::vector<std::vector<uint8_t>> valid_additional_cosigners) {
  return true;
}

void SimplePathBuilderDelegate::DebugLog(std::string_view msg) {}

SignatureVerifyCache *SimplePathBuilderDelegate::GetVerifyCache() {
  return nullptr;
}

bool SimplePathBuilderDelegate::IsSignatureAlgorithmAcceptable(
    SignatureAlgorithm algorithm, CertErrors *errors) {
  switch (algorithm) {
    case SignatureAlgorithm::kRsaPkcs1Sha1:
    case SignatureAlgorithm::kEcdsaSha1:
      return digest_policy_ == DigestPolicy::kWeakAllowSha1;

    case SignatureAlgorithm::kRsaPkcs1Sha256:
    case SignatureAlgorithm::kRsaPkcs1Sha384:
    case SignatureAlgorithm::kRsaPkcs1Sha512:
    case SignatureAlgorithm::kEcdsaSha256:
    case SignatureAlgorithm::kEcdsaSha384:
    case SignatureAlgorithm::kEcdsaSha512:
    case SignatureAlgorithm::kRsaPssSha256:
    case SignatureAlgorithm::kRsaPssSha384:
    case SignatureAlgorithm::kRsaPssSha512:
    case SignatureAlgorithm::kMtcProofDraftPlants04:
    case SignatureAlgorithm::kMtcProof:
    case SignatureAlgorithm::kMldsa44:
    case SignatureAlgorithm::kMldsa65:
    case SignatureAlgorithm::kMldsa87:
      return true;
  }
  return false;
}

bool SimplePathBuilderDelegate::IsPublicKeyAcceptable(
    const EVP_PKEY *public_key, CertErrors *errors) {
  int pkey_id = EVP_PKEY_id(public_key);
  if (pkey_id == EVP_PKEY_RSA) {
    // Extract the modulus length from the key.
    unsigned int modulus_length_bits = EVP_PKEY_bits(public_key);
    if (modulus_length_bits < min_rsa_modulus_length_bits_) {
      errors->AddWarning(
          kRsaModulusTooSmall,
          CreateCertErrorParams2SizeT("actual", modulus_length_bits, "minimum",
                                      min_rsa_modulus_length_bits_));
      return false;
    }

    return true;
  }

  if (pkey_id == EVP_PKEY_EC) {
    if (!IsAcceptableCurveForEcdsa(EVP_PKEY_get_ec_curve_nid(public_key))) {
      errors->AddWarning(kUnacceptableCurveForEcdsa);
      return false;
    }

    return true;
  }

  if (pkey_id == EVP_PKEY_ML_DSA_44 || pkey_id == EVP_PKEY_ML_DSA_65 ||
      pkey_id == EVP_PKEY_ML_DSA_87) {
    // ML-DSA keys are acceptable.
    return true;
  }

  // Unexpected key type.
  return false;
}

BSSL_NAMESPACE_END