key.h

/*
 * Copyright 2014 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.
 */

#ifndef SYSTEM_KEYMASTER_KEY_H_
#define SYSTEM_KEYMASTER_KEY_H_

#include <hardware/keymaster_defs.h>
#include <keymaster/authorization_set.h>
#include <keymaster/logger.h>

#include "abstract_factory_registry.h"
#include "unencrypted_key_blob.h"

namespace keymaster {

class Key;

/**
 * KeyFactory is a pure interface whose subclasses know how to construct a specific subclass of Key.
 * There is a one to one correspondence between Key subclasses and KeyFactory subclasses.
 */
class KeyFactory {
  public:
    virtual ~KeyFactory() {}

    // Required for registry
    typedef keymaster_algorithm_t KeyType;
    virtual keymaster_algorithm_t registry_key() const = 0;

    // Factory methods.
    virtual Key* GenerateKey(const AuthorizationSet& key_description, const Logger& logger,
                             keymaster_error_t* error) = 0;
    virtual Key* ImportKey(const AuthorizationSet& key_description,
                           keymaster_key_format_t key_format, const uint8_t* key_data,
                           size_t key_data_length, const Logger& logger,
                           keymaster_error_t* error) = 0;
    virtual Key* LoadKey(const UnencryptedKeyBlob& blob, const Logger& logger,
                         keymaster_error_t* error) = 0;

    // Informational methods.
    virtual const keymaster_key_format_t* SupportedImportFormats(size_t* format_count) = 0;
    virtual const keymaster_key_format_t* SupportedExportFormats(size_t* format_count) = 0;
};

typedef AbstractFactoryRegistry<KeyFactory> KeyFactoryRegistry;

class KeyBlob;
class Operation;
class UnencryptedKeyBlob;

class Key {
  public:
    virtual ~Key() {}
    virtual Operation* CreateOperation(keymaster_purpose_t purpose, keymaster_error_t* error) = 0;

    /**
     * Return a copy of raw key material, in the key's preferred binary format.
     */
    virtual keymaster_error_t key_material(UniquePtr<uint8_t[]>*, size_t* size) const = 0;

    /**
     * Return a copy of raw key material, in the specified format.
     */
    virtual keymaster_error_t formatted_key_material(keymaster_key_format_t format,
                                                     UniquePtr<uint8_t[]>* material,
                                                     size_t* size) const = 0;

    const AuthorizationSet& authorizations() const { return authorizations_; }

  protected:
    Key(const KeyBlob& blob, const Logger& logger);
    Key(const AuthorizationSet& authorizations, const Logger& logger)
        : logger_(logger), authorizations_(authorizations) {}

    const Logger& logger_;

  private:
    AuthorizationSet authorizations_;
};

}  // namespace keymaster

#endif  // SYSTEM_KEYMASTER_KEY_H_