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RSACipherImpl.cpp

//
// RSACipherImpl.cpp
//
// $Id: //poco/1.3/Crypto/src/RSACipherImpl.cpp#2 $
//
// Library: Crypto
// Package: CryptoCore
// Module:  RSACipherImpl
//
// Copyright (c) 2008, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#include "Poco/Crypto/RSACipherImpl.h"
#include "Poco/Crypto/CryptoTransform.h"
#include "Poco/Exception.h"
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <cstring>


namespace Poco {
namespace Crypto {


static void throwError()
{
      unsigned long err;
      std::string msg;
      
      while ((err = ERR_get_error()))
      {
            if (!msg.empty())
                  msg.append("; ");
            msg.append(ERR_error_string(err, 0));
      }

      throw Poco::IOException(msg);
}


class RSAEncryptImpl : public CryptoTransform
{
public:
      enum
      {
            OVERFLOW = 11
      };
      RSAEncryptImpl(
            const RSA* pRSA);

      ~RSAEncryptImpl();
      
      std::size_t blockSize() const;

      std::streamsize transform(
            const unsigned char* input,
            std::streamsize          inputLength,
            unsigned char*           output,
            std::streamsize          outputLength);
      
      std::streamsize finalize(
            unsigned char*    output,
            std::streamsize length);

private:
      std::streamsize _pos;
      const RSA*      _pRSA;
      unsigned char*  _pBuf;
};


RSAEncryptImpl::RSAEncryptImpl(
      const RSA* pRSA):
            _pos(0),
            _pRSA(pRSA),
            _pBuf(0)
{
      _pBuf = new unsigned char[blockSize()];
}


RSAEncryptImpl::~RSAEncryptImpl()
{
      delete _pBuf;
}


std::size_t RSAEncryptImpl::blockSize() const
{
      return RSA_size(_pRSA);
}


std::streamsize RSAEncryptImpl::transform(
      const unsigned char* input,
      std::streamsize          inputLength,
      unsigned char*           output,
      std::streamsize          outputLength)
{
      
      // always fill up the buffer before writing!
      std::streamsize rsaSize = blockSize();
      poco_assert_dbg(_pos <= rsaSize);
      poco_assert (outputLength >= rsaSize);
      int rc = 0;
      while (inputLength > 0)
      {
            // check how many data bytes we are missing to get the buffer full
            poco_assert_dbg (rsaSize >= _pos);
            std::streamsize missing = rsaSize - _pos;
            if (missing == 0)
            {
                  poco_assert (outputLength >= rsaSize);
                  int tmp = RSA_public_encrypt(rsaSize, _pBuf, output, const_cast<RSA*>(_pRSA), RSA_NO_PADDING);
                  if (tmp == -1)
                        throwError();
                  rc += tmp;
                  output += tmp;
                  outputLength -= tmp;
                  _pos = 0;
                  
            }
            else
            {
                  if (missing > inputLength)
                        missing = inputLength;

                  std::memcpy(_pBuf+_pos, input, missing);
                  input += missing;
                  _pos += missing;
                  inputLength -= missing;
            }
      }

      return rc;
}


std::streamsize RSAEncryptImpl::finalize(
      unsigned char*    output,
      std::streamsize length)
{
      poco_assert (length >= blockSize());
      int rc = 0;
      if (_pos > 0)
      {
            rc = RSA_public_encrypt(_pos, _pBuf, output, const_cast<RSA*>(_pRSA), RSA_PKCS1_PADDING);
            if (rc == -1)
                  throwError();
      }

      return rc;
}




class RSADecryptImpl : public CryptoTransform
{
public:
      enum
      {
            OVERFLOW = 11
      };
      RSADecryptImpl(
            const RSA* pRSA);

      ~RSADecryptImpl();
      
      std::size_t blockSize() const;

      std::streamsize transform(
            const unsigned char* input,
            std::streamsize          inputLength,
            unsigned char*           output,
            std::streamsize          outputLength);
      
      std::streamsize finalize(
            unsigned char*    output,
            std::streamsize length);

private:
      std::streamsize _pos;
      const RSA*      _pRSA;
      unsigned char*  _pBuf;
};


RSADecryptImpl::RSADecryptImpl(
      const RSA* pRSA):
            _pos(0),
            _pRSA(pRSA),
            _pBuf(0)
{
      _pBuf = new unsigned char[blockSize()];
}


RSADecryptImpl::~RSADecryptImpl()
{
      delete _pBuf;
}


std::size_t RSADecryptImpl::blockSize() const
{
      return RSA_size(_pRSA);
}


std::streamsize RSADecryptImpl::transform(
      const unsigned char* input,
      std::streamsize          inputLength,
      unsigned char*           output,
      std::streamsize          outputLength)
{
      
      // always fill up the buffer before decrypting!
      std::streamsize rsaSize = blockSize();
      poco_assert_dbg(_pos <= rsaSize);
      poco_assert (outputLength >= rsaSize);
      int rc = 0;
while (inputLength > 0)
      {
            // check how many data bytes we are missing to get the buffer full
            poco_assert_dbg (rsaSize >= _pos);
            std::streamsize missing = rsaSize - _pos;
            if (missing == 0)
            {
                  int tmp = RSA_private_decrypt(rsaSize, _pBuf, output, const_cast<RSA*>(_pRSA), RSA_NO_PADDING);
                  if (tmp == -1)
                        throwError();
                  rc += tmp;
                  output += tmp;
                  outputLength -= tmp;
                  _pos = 0;
                  
            }
            else
            {
                  if (missing > inputLength)
                        missing = inputLength;

                  std::memcpy(_pBuf+_pos, input, missing);
                  input += missing;
                  _pos += missing;
                  inputLength -= missing;
            }
      }

      return rc;
}


std::streamsize RSADecryptImpl::finalize(
      unsigned char*    output,
      std::streamsize length)
{
      poco_assert (length >= blockSize());
      int rc = 0;
      if (_pos > 0)
      {
            rc = RSA_private_decrypt(_pos, _pBuf, output, const_cast<RSA*>(_pRSA), RSA_PKCS1_PADDING);
            if (rc == -1)
                  throwError();
      }

      return rc;
}

RSACipherImpl::RSACipherImpl(const RSAKey& key):
      _key(key)
{
}


00301 RSACipherImpl::~RSACipherImpl()
{
}


00306 CryptoTransform* RSACipherImpl::createEncryptor()
{
      return new RSAEncryptImpl(_key.impl()->getRSA());
}


00312 CryptoTransform* RSACipherImpl::createDecryptor()
{
      return new RSADecryptImpl(_key.impl()->getRSA());
}


} } // namespace Poco::Crypto

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