C++ Section::fillSectionHeader方法代码示例

//! \todo Optimize writing section data. Right now it only writes one block at a
//!		time, which is of course quite slow (in relative terms).
//!	\todo Refactor this into several different methods for writing each region
//!		of the image. Use a context structure to keep track of shared data between
//!		each of the methods.
//! \todo Refactor the section and boot tag writing code to only have a single
//!		copy of the block writing and encryption loop.
void EncoreBootImage::writeToStream(std::ostream & stream)
{
	// always generate the session key or DEK even if image is unencrypted
	m_sessionKey.randomize();
	
	// prepare to compute CBC-MACs with each KEK
	unsigned i;
	smart_array_ptr<RijndaelCBCMAC> macs(0);
	if (isEncrypted())
	{
		macs = new RijndaelCBCMAC[m_keys.size()];
		for (i=0; i < m_keys.size(); ++i)
		{
			RijndaelCBCMAC mac(m_keys[i]);
			(macs.get())[i] = mac;
		}
	}
	
	// prepare to compute SHA-1 digest over entire image
	CSHA1 hash;
	hash.Reset();
	
	// count of total blocks written to the file
	unsigned fileBlocksWritten = 0;

	// we need some pieces of the header down below
	boot_image_header_t imageHeader;
	prepareImageHeader(imageHeader);
	
	// write plaintext header
	{
		// write header
		assert(sizeOfPaddingForCipherBlocks(sizeof(boot_image_header_t)) == 0);
		stream.write(reinterpret_cast<char *>(&imageHeader), sizeof(imageHeader));
		fileBlocksWritten += numberOfCipherBlocks(sizeof(imageHeader));
		
		// update CBC-MAC over image header
		if (isEncrypted())
		{
			for (i=0; i < m_keys.size(); ++i)
			{
				(macs.get())[i].update(reinterpret_cast<uint8_t *>(&imageHeader), sizeof(imageHeader));
			}
		}
		
		// update SHA-1
		hash.Update(reinterpret_cast<uint8_t *>(&imageHeader), sizeof(imageHeader));
	}
	
	// write plaintext section table
	{
		section_iterator_t it = beginSection();
		for (; it != endSection(); ++it)
		{
			Section * section = *it;
			
			// write header for this section
			assert(sizeOfPaddingForCipherBlocks(sizeof(section_header_t)) == 0);
			section_header_t sectionHeader;
			section->fillSectionHeader(sectionHeader);
			stream.write(reinterpret_cast<char *>(&sectionHeader), sizeof(sectionHeader));
			fileBlocksWritten += numberOfCipherBlocks(sizeof(sectionHeader));
			
			// update CBC-MAC over this entry
			if (isEncrypted())
			{
				for (i=0; i < m_keys.size(); ++i)
				{
					(macs.get())[i].update(reinterpret_cast<uint8_t *>(&sectionHeader), sizeof(sectionHeader));
				}
			}
			
			// update SHA-1
			hash.Update(reinterpret_cast<uint8_t *>(&sectionHeader), sizeof(sectionHeader));
		}
	}
	
	// finished with the CBC-MAC
	if (isEncrypted())
	{
		for (i=0; i < m_keys.size(); ++i)
		{
			(macs.get())[i].finalize();
		}
	}
	
	// write key dictionary
	if (isEncrypted())
	{
		key_iterator_t it = beginKeys();
		for (i=0; it != endKeys(); ++it, ++i)
		{
			// write CBC-MAC result for this key, then update SHA-1
//.........这里部分代码省略.........