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CipherImpl.cpp

//
// CipherImpl.cpp
//
// $Id: //poco/1.3/Crypto/src/CipherImpl.cpp#2 $
//
// Library: Crypto
// Package: CryptoCore
// Module:  CipherImpl
//
// 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/CipherImpl.h"
#include "Poco/Crypto/CryptoTransform.h"
#include "Poco/Exception.h"
#include <openssl/err.h>


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 CryptoTransformImpl : public CryptoTransform
{
public:
      typedef Cipher::ByteVec ByteVec;

      enum Direction
      {
            DIR_ENCRYPT,
            DIR_DECRYPT
      };

      CryptoTransformImpl(
            const EVP_CIPHER* pCipher,
            const ByteVec&    key,
            const ByteVec&    iv,
            Direction         dir);

      ~CryptoTransformImpl();
      
      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:
      const EVP_CIPHER* _pCipher;
      EVP_CIPHER_CTX    _ctx;
      ByteVec           _key;
      ByteVec           _iv;
};


CryptoTransformImpl::CryptoTransformImpl(
      const EVP_CIPHER* pCipher,
      const ByteVec&    key,
      const ByteVec&    iv,
      Direction         dir) :
            _pCipher(pCipher),
            _key(key),
            _iv(iv)
{
      EVP_CipherInit(
            &_ctx,
            _pCipher,
            &_key[0],
            &_iv[0],
            (dir == DIR_ENCRYPT) ? 1 : 0);
}


CryptoTransformImpl::~CryptoTransformImpl()
{
      EVP_CIPHER_CTX_cleanup(&_ctx);
}


std::size_t CryptoTransformImpl::blockSize() const
{
      return EVP_CIPHER_CTX_block_size(&_ctx);
}


std::streamsize CryptoTransformImpl::transform(
      const unsigned char* input,
      std::streamsize      inputLength,
      unsigned char*       output,
      std::streamsize      outputLength)
{
      poco_assert (outputLength >= (inputLength + blockSize() - 1));

      int outLen = static_cast<int>(outputLength);
      int rc = EVP_CipherUpdate(
            &_ctx,
            output,
            &outLen,
            input,
            static_cast<int>(inputLength));

      if (rc == 0)
            throwError();

      return static_cast<std::streamsize>(outLen);
}


std::streamsize CryptoTransformImpl::finalize(
      unsigned char*    output,
      std::streamsize length)
{
      poco_assert (length >= blockSize());
      
      int len = static_cast<int>(length);

      // Use the '_ex' version that does not perform implicit cleanup since we
      // will call EVP_CIPHER_CTX_cleanup() from the dtor as there is no
      // guarantee that finalize() will be called if an error occurred.
      int rc = EVP_CipherFinal_ex(&_ctx, output, &len);

      if (rc == 0)
            throwError();
            
      return static_cast<std::streamsize>(len);
}


CipherImpl::CipherImpl(const CipherKey& key):
      _key(key)
{
}


00181 CipherImpl::~CipherImpl()
{
}


00186 CryptoTransform* CipherImpl::createEncryptor()
{
      CipherKeyImpl::Ptr p = _key.impl();
      return new CryptoTransformImpl(p->cipher(), p->getKey(), p->getIV(),
            CryptoTransformImpl::DIR_ENCRYPT);
}


00194 CryptoTransform* CipherImpl::createDecryptor()
{
      CipherKeyImpl::Ptr p = _key.impl();
      return new CryptoTransformImpl(p->cipher(), p->getKey(), p->getIV(),
            CryptoTransformImpl::DIR_DECRYPT);
}


} } // namespace Poco::Crypto

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