cc/jwt/internal/raw_jwt_rsa_ssa_pss_verify_key_manager.cc

// Copyright 2021 Google LLC
//
// 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.
//
///////////////////////////////////////////////////////////////////////////////

#include "tink/jwt/internal/raw_jwt_rsa_ssa_pss_verify_key_manager.h"

#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "tink/public_key_verify.h"
#include "tink/subtle/rsa_ssa_pss_verify_boringssl.h"
#include "tink/subtle/subtle_util_boringssl.h"
#include "tink/util/enums.h"
#include "tink/util/errors.h"
#include "tink/util/protobuf_helper.h"
#include "tink/util/status.h"
#include "tink/util/statusor.h"
#include "tink/util/validation.h"
#include "proto/jwt_rsa_ssa_pss.pb.h"
#include "proto/tink.pb.h"

namespace crypto {
namespace tink {

using crypto::tink::util::Enums;
using crypto::tink::util::Status;
using crypto::tink::util::StatusOr;
using google::crypto::tink::JwtRsaSsaPssAlgorithm;
using google::crypto::tink::JwtRsaSsaPssPublicKey;
using google::crypto::tink::HashType;

StatusOr<std::unique_ptr<PublicKeyVerify>>
RawJwtRsaSsaPssVerifyKeyManager::PublicKeyVerifyFactory::Create(
    const JwtRsaSsaPssPublicKey& rsa_ssa_pss_public_key) const {
  subtle::SubtleUtilBoringSSL::RsaPublicKey rsa_pub_key;
  rsa_pub_key.n = rsa_ssa_pss_public_key.n();
  rsa_pub_key.e = rsa_ssa_pss_public_key.e();
  JwtRsaSsaPssAlgorithm algorithm = rsa_ssa_pss_public_key.algorithm();
  StatusOr<HashType> hash_or = HashForPssAlgorithm(algorithm);
  if (!hash_or.ok()) {
    return hash_or.status();
  }
  StatusOr<int> salt_length_or = SaltLengthForPssAlgorithm(algorithm);
  if (!salt_length_or.ok()) {
    return salt_length_or.status();
  }
  subtle::SubtleUtilBoringSSL::RsaSsaPssParams params;
  params.sig_hash = Enums::ProtoToSubtle(hash_or.ValueOrDie());
  params.mgf1_hash = Enums::ProtoToSubtle(hash_or.ValueOrDie());
  params.salt_length = salt_length_or.ValueOrDie();

  auto rsa_ssa_pss_result =
      subtle::RsaSsaPssVerifyBoringSsl::New(rsa_pub_key, params);
  if (!rsa_ssa_pss_result.ok()) return rsa_ssa_pss_result.status();
  return {std::move(rsa_ssa_pss_result).ValueOrDie()};
}

Status RawJwtRsaSsaPssVerifyKeyManager::ValidateKey(
    const JwtRsaSsaPssPublicKey& key) const {
  Status status = ValidateVersion(key.version(), get_version());
  if (!status.ok()) return status;
  auto status_or_n = subtle::SubtleUtilBoringSSL::str2bn(key.n());
  if (!status_or_n.ok()) return status_or_n.status();
  auto modulus_status = subtle::SubtleUtilBoringSSL::ValidateRsaModulusSize(
      BN_num_bits(status_or_n.ValueOrDie().get()));
  if (!modulus_status.ok()) return modulus_status;
  auto exponent_status = subtle::SubtleUtilBoringSSL::ValidateRsaPublicExponent(
      key.e());
  if (!exponent_status.ok()) return exponent_status;
  return ValidateAlgorithm(key.algorithm());
}

Status RawJwtRsaSsaPssVerifyKeyManager::ValidateAlgorithm(
    const JwtRsaSsaPssAlgorithm& algorithm) {
  switch (algorithm) {
    case JwtRsaSsaPssAlgorithm::PS256:
    case JwtRsaSsaPssAlgorithm::PS384:
    case JwtRsaSsaPssAlgorithm::PS512:
      return Status::OK;
    default:
      return Status(util::error::INVALID_ARGUMENT,
                    "Unsupported RSA SSA PSS Algorithm");
  }
  return Status::OK;
}

StatusOr<HashType> RawJwtRsaSsaPssVerifyKeyManager::HashForPssAlgorithm(
    const JwtRsaSsaPssAlgorithm& algorithm) {
  switch (algorithm) {
    case JwtRsaSsaPssAlgorithm::PS256:
      return HashType::SHA256;
    case JwtRsaSsaPssAlgorithm::PS384:
      return HashType::SHA384;
    case JwtRsaSsaPssAlgorithm::PS512:
      return HashType::SHA512;
    default:
      return Status(util::error::INVALID_ARGUMENT,
                    "Unsupported RSA SSA PSS Algorithm");
  }
}

StatusOr<int> RawJwtRsaSsaPssVerifyKeyManager::SaltLengthForPssAlgorithm(
    const JwtRsaSsaPssAlgorithm& algorithm) {
  switch (algorithm) {
    case JwtRsaSsaPssAlgorithm::PS256:
      return 32;
    case JwtRsaSsaPssAlgorithm::PS384:
      return 48;
    case JwtRsaSsaPssAlgorithm::PS512:
      return 64;
    default:
      return Status(util::error::INVALID_ARGUMENT,
                    "Unsupported RSA SSA PSS Algorithm");
  }
}

}  // namespace tink
}  // namespace crypto