Not-safe function strcpy, possible buffer overflow #901

There [1][2] we use strcpy, first arg may contain MAX_PATH+100 (355) chars, but second arg may contain 32,767 chars [3]

[1] https://github.com/bitcoin/bitcoin/blob/master/src/util.cpp#L820 [2] https://github.com/bitcoin/bitcoin/blob/master/src/util.cpp#L825 [3] http://msdn.microsoft.com/en-us/library/windows/desktop/ms682653(v=vs.85).aspx

So we just need an strlen check before copying, as no meaningful value in APPDATA is longer than MAX_PATH?

Maybe we should strive to use safe C++ string functions everywhere, instead of archaic strcpy/strcat buffer manipulation.

Edit: especially in this case, as the function returns a std::string already.

Edit2: the rest of the function could be simplified too, to simply call SHGetSpecialFolderPathA, as we require _WINNT 0x0501 (Windows XP) and the function was introduced in 5.0 (Windows 2000).

Fixed in #902.