UID/GID bug in chrooted shells fixed.

[Dave Dykstra]

On Fri, Jun 14, 2002 at 11:51:56AM +0100, Tom Worley wrote:
> On Friday 14 June 2002 12:09 am, Martin Pool wrote:
> > I'm not how that script will cause them to be set, but it may be
> > eff=root, real=testluser.  In that case rsync will probably get pretty
> > confused, because I think it calls getuid() and will therefore think
> > it's not root, even though it is.  As Dave says, this is not a
> > supported mode of operation: rsync wants to either be root, or not,
> > but not halfway.
> Ok, I'm not sure if this may cause any other issues, however I altered the 
> main.c code, line 858, from:
>         am_root = (getuid() == 0);
> to:
>         am_root = (geteuid() == 0);
> It compiles without problem, and works perfectly under our conditions, and 
> also works without setuid root as a normal, non-root, user, and also returns 
> the correct uid for root when run without setuid root as root (if you see 
> what I mean). Basically it works with/without setuid root, inside or outside 
> a chroot jail with a root or non-root user as it should do.

Uh, I suppose you could do it that assuming you don't mind the fact that
there's bound to be zillions of ways for somebody with a real login on your
machine to use it give themselves root access, but even with that rsync
still might be confused.  If you'd rather modify rsync than write a
wrapper, something that will be likely to cause rsync less confusion is

    if (geteuid() == 0)
	setuid(0);

- Dave Dykstra