Re: setuid(geteuid());?

> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > so it seems to make sure the real/saved uid matches the effective uid.
> > Now, considering we don't use uid/euid distinction for anything, I agree
> > it is useless and should be removed.
>
> No, it is NOT useless and must NOT be removed. The point of this little
> machination is to be dead certain that we have given up root rights if
> executed as setuid postgres. The scenario we're concerned about is
> where real uid = root and effective uid = postgres. We want real uid
> to become postgres as well --- otherwise our test to prevent execution
> as root is a waste of time, because nefarious code could become root
> again just by doing setuid. See the setuid man page: if real uid is
> root then setuid(root) will succeed.

I understand, but how do we get suid execution. Does someone have to
set the seuid bit on the executable?

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