signer-filter.cpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013-2023 Regents of the University of California.
 *
 * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
 *
 * ndn-cxx library is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received copies of the GNU General Public License and GNU Lesser
 * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
 */
 
#include "ndn-cxx/security/transform/signer-filter.hpp"
#include "ndn-cxx/security/transform/private-key.hpp"
#include "ndn-cxx/security/impl/openssl-helper.hpp"
 
#include <boost/lexical_cast.hpp>
 
namespace ndn::security::transform {
 
class SignerFilter::Impl
{
public:
  detail::EvpMdCtx ctx;
};
 
 
SignerFilter::SignerFilter(DigestAlgorithm algo, const PrivateKey& key)
  : m_impl(make_unique<Impl>())
{
  const EVP_MD* md = detail::digestAlgorithmToEvpMd(algo);
  if (md == nullptr)
    NDN_THROW(Error(getIndex(), "Unsupported digest algorithm " +
                    boost::lexical_cast<std::string>(algo)));
 
  if (EVP_DigestSignInit(m_impl->ctx, nullptr, md, nullptr,
                         reinterpret_cast<EVP_PKEY*>(key.getEvpPkey())) != 1)
    NDN_THROW(Error(getIndex(), "Failed to initialize signing context with " +
                    boost::lexical_cast<std::string>(algo) + " digest and " +
                    boost::lexical_cast<std::string>(key.getKeyType()) + " key"));
}
 
SignerFilter::~SignerFilter() = default;
 
size_t
SignerFilter::convert(span<const uint8_t> buf)
{
  if (EVP_DigestSignUpdate(m_impl->ctx, buf.data(), buf.size()) != 1)
    NDN_THROW(Error(getIndex(), "Failed to accept more input"));
 
  return buf.size();
}
 
void
SignerFilter::finalize()
{
  size_t sigLen = 0;
  if (EVP_DigestSignFinal(m_impl->ctx, nullptr, &sigLen) != 1)
    NDN_THROW(Error(getIndex(), "Failed to estimate buffer length"));
 
  auto buffer = make_unique<OBuffer>(sigLen);
  if (EVP_DigestSignFinal(m_impl->ctx, buffer->data(), &sigLen) != 1)
    NDN_THROW(Error(getIndex(), "Failed to finalize signature"));
 
  buffer->erase(buffer->begin() + sigLen, buffer->end());
  setOutputBuffer(std::move(buffer));
 
  flushAllOutput();
}
 
unique_ptr<Transform>
signerFilter(DigestAlgorithm algo, const PrivateKey& key)
{
  return make_unique<SignerFilter>(algo, key);
}
 
} // namespace ndn::security::transform