kernel32: Avoid two potential buffer overflows of cStr in create_hardware_branch.

[Gerald Pfeifer]

On Sun, 9 Oct 2016, Sebastian Lackner wrote:
> On 08.10.2016 22:31, Gerald Pfeifer wrote:
>> +    char cStr[sizeof(dent->d_name)+sizeof(procname_ide_media)],
> http://man7.org/linux/man-pages/man3/readdir.3.html says:
> 
> """The standard also notes that the use of sizeof(d_name) is
> incorrect; use strlen(d_name) instead.  (On some systems, this field
> is defined as char d_name[1]!)"""
> 
> This means your solution will not work on all systems.

Interesting, thanks!  Does this happen on any system we care about? 

I checked a current GNU/Linux system and FreeBSD, and on both 
sizeof(d_name) works.  Still, good to make this more portable,
so would 

  char cStr[NAME_MAX+sizeof(procname_ide_media)]

work?

According to that man page

  Warning: applications should avoid any dependence on the  size  of  the
  d_name  field.  POSIX defines it as char d_name[], a character array of
  unspecified size, with at most NAME_MAX characters preceding the termi-
  nating null byte ('\0').

so we should be fine, shouldn't we?

Gerald