src/platform/EFR32/GroupKeyStoreImpl.h

/*
 *
 *    Copyright (c) 2020 Project CHIP Authors
 *    Copyright (c) 2019 Nest Labs, Inc.
 *
 *    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.
 */

/**
 *    @file
 *          Provides an implementation of the Chip Group Key Store interface
 *          for platforms based on the Silicon Labs SDK.
 */

#include <Core/CHIPKeyIds.h>
#include <platform/EFR32/EFR32Config.h>
#include <platform/Profiles/security/ChipApplicationKeys.h>
#include <platform/internal/CHIPDeviceLayerInternal.h>

namespace chip {
namespace DeviceLayer {
namespace Internal {

/**
 * An implementation of the Chip GroupKeyStoreBase API for platforms based
 * on the Silicon Labs SDK.
 */
class GroupKeyStoreImpl final : public ::chip::Profiles::Security::AppKeys::GroupKeyStoreBase, private EFR32Config
{
    using ChipGroupKey = ::chip::Profiles::Security::AppKeys::ChipGroupKey;

public:
    CHIP_ERROR Init();

    CHIP_ERROR RetrieveGroupKey(uint32_t keyId, ChipGroupKey & key) override;
    CHIP_ERROR StoreGroupKey(const ChipGroupKey & key) override;
    CHIP_ERROR DeleteGroupKey(uint32_t keyId) override;
    CHIP_ERROR DeleteGroupKeysOfAType(uint32_t keyType) override;
    CHIP_ERROR EnumerateGroupKeys(uint32_t keyType, uint32_t * keyIds, uint8_t keyIdsArraySize, uint8_t & keyCount) override;
    CHIP_ERROR Clear(void) override;
    CHIP_ERROR RetrieveLastUsedEpochKeyId(void) override;
    CHIP_ERROR StoreLastUsedEpochKeyId(void) override;

private:
    static constexpr size_t kFixedEncodedKeySize = 4U + // key id
        4U +                                            // start time / global id
        1U;                                             // key data length

    static constexpr size_t kMaxEncodedKeySize = kFixedEncodedKeySize + ChipGroupKey::MaxKeySize;

    /* Not used
    static constexpr uint16_t kGroupKeyFileId =     GetFileId(kConfigKey_GroupKey);
    static constexpr uint16_t kGroupKeyRecordKey =  GetRecordKey(kConfigKey_GroupKey);
    */

    static CHIP_ERROR EncodeGroupKey(const ChipGroupKey & key, uint8_t * buf, size_t bufSize, size_t & encodedKeyLen);
    static CHIP_ERROR DecodeGroupKey(const uint8_t * encodedKey, size_t encodedKeyLen, ChipGroupKey & key);
    static CHIP_ERROR DecodeGroupKeyId(const uint8_t * encodedKey, size_t encodedKeyLen, uint32_t & keyId);
};

} // namespace Internal
} // namespace DeviceLayer
} // namespace chip