Re: setuid in gdomap - bug or feature?

[Richard Frith-Macdonald]

On Friday, May 4, 2001, at 01:25 AM, Chris B. Vetter wrote:

> Hi,
>
> I'm not sure if this is a bug or a feature, but I'm running in all kinds
> of trouble with gdomap's setuid(3) call in main().
>
> Instead of
>
>   if (getuid () != 0)
>     {
>       setuid (getuid ());
>     }
>   else
>     {
>       setuid (-1);
>     }
>
> which (on my box) keeps gdomap running with UID 4294967295, a call to
> getpwnam(3) similar to
>
>         struct passwd *pw = getpwnam("nobody");
>         setuid(pw->pw_uid);
>
> would probably be a much "cleaner" approach.

I've changed the code to try using the user 'nobody' before resorting to 
uid -2
(-1 was a typo ... this should be consistent with the standard
usage of -2 to denote a user with no access).  Some older unices don't 
have a
user 'nobody' by default, and common practice of applications like NFS 
is to use -2.

So, current behavior is ...

If started by a non-root user, run as that user so they are able to kill 
the process.
If started by root, run as user nobody (if found) else as user -2

All that being said ... I don't understand why this has been causing you 
any trouble.