examples/fabric-admin/commands/pairing/ToTLVCert.cpp

/*
 *   Copyright (c) 2024 Project CHIP Authors
 *   All rights reserved.
 *
 *   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 "ToTLVCert.h"

#include <credentials/CHIPCert.h>
#include <lib/support/Base64.h>

#include <string>

constexpr char kBase64Header[]    = "base64:";
constexpr size_t kBase64HeaderLen = ArraySize(kBase64Header) - 1;

CHIP_ERROR ToBase64(const chip::ByteSpan & input, std::string & outputAsPrefixedBase64)
{
    chip::Platform::ScopedMemoryBuffer<char> base64String;
    base64String.Alloc(kBase64HeaderLen + BASE64_ENCODED_LEN(input.size()) + 1);
    VerifyOrReturnError(base64String.Get() != nullptr, CHIP_ERROR_NO_MEMORY);

    auto encodedLen = chip::Base64Encode(input.data(), static_cast<uint16_t>(input.size()), base64String.Get() + kBase64HeaderLen);
    if (encodedLen)
    {
        memcpy(base64String.Get(), kBase64Header, kBase64HeaderLen);
        encodedLen = static_cast<uint16_t>(encodedLen + kBase64HeaderLen);
    }
    base64String.Get()[encodedLen] = '\0';
    outputAsPrefixedBase64         = std::string(base64String.Get(), encodedLen);

    return CHIP_NO_ERROR;
}

CHIP_ERROR ToTLVCert(const chip::ByteSpan & derEncodedCertificate, std::string & tlvCertAsPrefixedBase64)
{
    uint8_t chipCertBuffer[chip::Credentials::kMaxCHIPCertLength];
    chip::MutableByteSpan chipCertBytes(chipCertBuffer);
    ReturnErrorOnFailure(chip::Credentials::ConvertX509CertToChipCert(derEncodedCertificate, chipCertBytes));
    ReturnErrorOnFailure(ToBase64(chipCertBytes, tlvCertAsPrefixedBase64));
    return CHIP_NO_ERROR;
}