guest/hals/gatekeeper/remote/remote_gatekeeper.cpp

/*
 * Copyright (C) 2015 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 "RemoteGateKeeper"

#include "remote_gatekeeper.h"

#include <limits>

#include <android-base/logging.h>

using ::android::hardware::hidl_vec;
using ::android::hardware::Return;
using ::android::hardware::gatekeeper::V1_0::GatekeeperStatusCode;
using ::gatekeeper::EnrollRequest;
using ::gatekeeper::EnrollResponse;
using ::gatekeeper::ERROR_INVALID;
using ::gatekeeper::ERROR_MEMORY_ALLOCATION_FAILED;
using ::gatekeeper::ERROR_NONE;
using ::gatekeeper::ERROR_RETRY;
using ::gatekeeper::SizedBuffer;
using ::gatekeeper::VerifyRequest;
using ::gatekeeper::VerifyResponse;

namespace gatekeeper {

RemoteGateKeeperDevice::RemoteGateKeeperDevice(cuttlefish::GatekeeperChannel* channel)
    : gatekeeper_channel_(channel), error_(0) {
}

RemoteGateKeeperDevice::~RemoteGateKeeperDevice() {
}

SizedBuffer hidl_vec2sized_buffer(const hidl_vec<uint8_t>& vec) {
    if (vec.size() == 0 || vec.size() > std::numeric_limits<uint32_t>::max()) return {};
    auto unused = new uint8_t[vec.size()];
    std::copy(vec.begin(), vec.end(), unused);
    return {unused, static_cast<uint32_t>(vec.size())};
}

Return<void> RemoteGateKeeperDevice::enroll(uint32_t uid,
                                            const hidl_vec<uint8_t>& currentPasswordHandle,
                                            const hidl_vec<uint8_t>& currentPassword,
                                            const hidl_vec<uint8_t>& desiredPassword,
                                            enroll_cb _hidl_cb) {
    if (error_ != 0) {
        LOG(ERROR) << "Gatekeeper in invalid state";
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
        return {};
    }

    if (desiredPassword.size() == 0) {
        LOG(ERROR) << "Desired password size is 0";
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
        return {};
    }

    EnrollRequest request(uid, hidl_vec2sized_buffer(currentPasswordHandle),
                          hidl_vec2sized_buffer(desiredPassword),
                          hidl_vec2sized_buffer(currentPassword));
    EnrollResponse response;
    auto error = Send(request, &response);
    if (error != ERROR_NONE) {
        LOG(ERROR) << "Enroll request gave error: " << error;
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
    } else if (response.error == ERROR_RETRY) {
        LOG(ERROR) << "Enroll response has a retry error";
        _hidl_cb({GatekeeperStatusCode::ERROR_RETRY_TIMEOUT, response.retry_timeout, {}});
    } else if (response.error != ERROR_NONE) {
        LOG(ERROR) << "Enroll response has an error: " << response.error;
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
    } else {
        hidl_vec<uint8_t> new_handle(response.enrolled_password_handle.Data<uint8_t>(),
                                     response.enrolled_password_handle.Data<uint8_t>() +
                                             response.enrolled_password_handle.size());
        _hidl_cb({GatekeeperStatusCode::STATUS_OK, response.retry_timeout, new_handle});
    }
    return {};
}

Return<void> RemoteGateKeeperDevice::verify(
        uint32_t uid, uint64_t challenge,
        const ::android::hardware::hidl_vec<uint8_t>& enrolledPasswordHandle,
        const ::android::hardware::hidl_vec<uint8_t>& providedPassword, verify_cb _hidl_cb) {
    if (error_ != 0) {
        LOG(ERROR) << "Gatekeeper in invalid state";
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
        return {};
    }

    if (enrolledPasswordHandle.size() == 0) {
        LOG(ERROR) << "Enrolled password size is 0";
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
        return {};
    }

    VerifyRequest request(uid, challenge, hidl_vec2sized_buffer(enrolledPasswordHandle),
                          hidl_vec2sized_buffer(providedPassword));
    VerifyResponse response;

    auto error = Send(request, &response);
    if (error != ERROR_NONE) {
        LOG(ERROR) << "Verify request gave error: " << error;
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
    } else if (response.error == ERROR_RETRY) {
        LOG(ERROR) << "Verify request response gave retry error";
        _hidl_cb({GatekeeperStatusCode::ERROR_RETRY_TIMEOUT, response.retry_timeout, {}});
    } else if (response.error != ERROR_NONE) {
        LOG(ERROR) << "Verify request response gave error: " << response.error;
        _hidl_cb({GatekeeperStatusCode::ERROR_GENERAL_FAILURE, 0, {}});
    } else {
        hidl_vec<uint8_t> auth_token(
                response.auth_token.Data<uint8_t>(),
                response.auth_token.Data<uint8_t>() + response.auth_token.size());

        _hidl_cb({response.request_reenroll ? GatekeeperStatusCode::STATUS_REENROLL
                                            : GatekeeperStatusCode::STATUS_OK,
                  response.retry_timeout, auth_token});
    }
    return {};
}

Return<void> RemoteGateKeeperDevice::deleteUser(uint32_t /*uid*/, deleteUser_cb _hidl_cb) {
    LOG(ERROR) << "deleteUser is unimplemented";
    _hidl_cb({GatekeeperStatusCode::ERROR_NOT_IMPLEMENTED, 0, {}});
    return {};
}

Return<void> RemoteGateKeeperDevice::deleteAllUsers(deleteAllUsers_cb _hidl_cb) {
    LOG(ERROR) << "deleteAllUsers is unimplemented";
    _hidl_cb({GatekeeperStatusCode::ERROR_NOT_IMPLEMENTED, 0, {}});
    return {};
}

gatekeeper_error_t RemoteGateKeeperDevice::Send(uint32_t command, const GateKeeperMessage& request,
        GateKeeperMessage *response) {
    if (!gatekeeper_channel_->SendRequest(command, request)) {
      LOG(ERROR) << "Failed to send request";
      return ERROR_UNKNOWN;
    }
    auto remote_response = gatekeeper_channel_->ReceiveMessage();
    if (!remote_response) {
      LOG(ERROR) << "Failed to receive response";
      return ERROR_UNKNOWN;
    }
    const uint8_t* buffer = remote_response->payload;
    const uint8_t* buffer_end = remote_response->payload + remote_response->payload_size;
    auto rc = response->Deserialize(buffer, buffer_end);
    if (rc != ERROR_NONE) {
        LOG(ERROR) << "Failed to deserialize keymaster response: " << command;
        return ERROR_UNKNOWN;
    }
    return rc;
}

};