guest/hals/keymint/remote/remote_shared_secret.cpp

/*
 * Copyright 2020, The Android Open Source Project
 *
 * 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.
 */

#define LOG_TAG "android.hardware.security.sharedsecret-impl"
#include <log/log.h>

#include "guest/hals/keymint/remote/remote_shared_secret.h"

#include <aidl/android/hardware/security/keymint/ErrorCode.h>
#include <keymaster/android_keymaster.h>
#include "KeyMintUtils.h"

namespace aidl::android::hardware::security::sharedsecret {

using namespace ::keymaster;
using namespace ::aidl::android::hardware::security::keymint::km_utils;

RemoteSharedSecret::RemoteSharedSecret(::keymaster::RemoteKeymaster& keymint)
    : impl_(keymint) {}

RemoteSharedSecret::~RemoteSharedSecret() {}

ScopedAStatus RemoteSharedSecret::getSharedSecretParameters(
    SharedSecretParameters* params) {
  auto response = impl_.GetHmacSharingParameters();
  params->seed = kmBlob2vector(response.params.seed);
  params->nonce = {std::begin(response.params.nonce),
                   std::end(response.params.nonce)};
  return kmError2ScopedAStatus(response.error);
}

ScopedAStatus RemoteSharedSecret::computeSharedSecret(
    const vector<SharedSecretParameters>& params,
    vector<uint8_t>* sharingCheck) {
  ComputeSharedHmacRequest request(impl_.message_version());
  request.params_array.params_array =
      new keymaster::HmacSharingParameters[params.size()];
  request.params_array.num_params = params.size();
  for (size_t i = 0; i < params.size(); ++i) {
    request.params_array.params_array[i].seed = {params[i].seed.data(),
                                                 params[i].seed.size()};
    if (sizeof(request.params_array.params_array[i].nonce) !=
        params[i].nonce.size()) {
      return kmError2ScopedAStatus(KM_ERROR_INVALID_ARGUMENT);
    }
    memcpy(request.params_array.params_array[i].nonce, params[i].nonce.data(),
           params[i].nonce.size());
  }
  auto response = impl_.ComputeSharedHmac(request);
  if (response.error == KM_ERROR_OK)
    *sharingCheck = kmBlob2vector(response.sharing_check);
  return kmError2ScopedAStatus(response.error);
}

}  // namespace aidl::android::hardware::security::sharedsecret