getgrouplist segfault?

[Roland Illig]

Pavel Tsekov wrote:
> BUGS
>        The glibc 2.3.2 implementation of this function is broken: it
>        overwrites memory when the actual number of groups  is  larger
>        than *ngroups.

As this is clearly a buffer overflow, we should not use the function at 
all and document this somewhere. Maybe like that:

#if 0
/* the glibc implementation of getgrouplist(3) has a
  * buffer overflow vulnerability, so we cannot use this function */
...
#endif

Roland