Function decrypt_filename

libcppcryptfs/filename/cryptfilename.cpp:278–386

const WCHAR * // returns UNICODE plaintext filename
decrypt_filename(CryptContext *con, const BYTE *dir_iv, const WCHAR *path, const WCHAR *filename, wstring& storage)
{
	static ValidFileNameCharChecker char_checker;

	if (con->GetConfig()->m_PlaintextNames) {
		storage = filename;
		return &storage[0];
	}

	wstring file_without_stream;
	wstring stream;

	bool have_stream = get_file_stream(filename, &file_without_stream, &stream);

	vector<unsigned char> ctstorage;

	char longname_buf[4096];

	wstring longname_storage;

	if (!wcsncmp(file_without_stream.c_str(), longname_prefix, sizeof(longname_prefix)/sizeof(longname_prefix[0])-1)) {
		if (con->GetConfig()->m_reverse) {
			if (decrypt_reverse_longname(con, file_without_stream.c_str(), path, dir_iv, storage))
				return &storage[0];
			else
				return nullptr;
		} else {
			wstring fullpath = path;
			if (fullpath[fullpath.size() - 1] != '\\')
				fullpath.push_back('\\');

			fullpath += file_without_stream.c_str();
			fullpath += longname_suffix;

			HANDLE hFile = CreateFile(&fullpath[0], GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

			if (hFile == INVALID_HANDLE_VALUE)
				return NULL;

			DWORD nRead;

			if (!ReadFile(hFile, longname_buf, sizeof(longname_buf)-1, &nRead, NULL)) {
				CloseHandle(hFile);
				return NULL;
			}

			CloseHandle(hFile);

			if (nRead < 1)
				return NULL;

			longname_buf[nRead] = '\0';

			if (!utf8_to_unicode(longname_buf, longname_storage))
				return NULL;

			file_without_stream = &longname_storage[0];