chroot and wrong user names

Riq Willitts riq at scs.co.uk
Thu Sep 19 10:11:00 EST 2002


Thank you for the prompt and clear reply. That should settle the matter.


At 02:41 19/09/02 -0700, you wrote:
>On Thu, Sep 19, 2002 at 10:02:18AM +0100, Riq Willitts wrote:
> > I am using rsync 2.5.5 running as a daemon on the destination system, 
> which
> > is SuSE Linux 8.0. The source system is SuSE 7.3, also with rsync 2.5.5.
> > With the default 'use chroot = true' and not using  --numeric-ids, I get
> > the wrong user names on the destination files. I have tracked this 
> down  to
> > getpwnam() failing to return the user name from the passwd file. It does
> > not fail when chroot() is not called ( by setting 'use chroot = false' in
> > rsyncd.conf).
> >
> > A simple test program calling chroot() followed by getpwnam() shows the
> > same effect, so the problem is not really in rsync.
> >
> > As I wasted quite a lot of time discovering this, it could be helpful to
> > put a warning in the documentation of rsync.
> >
> > For some reason errno is zero on return from getpwnam() in the above case,
> > although in my test program it is set to 29 (no such file or 
> directory). It
> > would therefore not be very useful to test errno in the rsync code.
>
>Because too many people no longer seemed to understand the
>implications of chroot this has already been done in CVS.
>
>The rsyncd.conf.5 manpage specifically mentions this under the
>"use chroot" directive.
>
>         it has the disadvantages of ... implying the
>         --numeric-ids option because /etc/passwd becomes
>         inaccessible.
>
>It is also specified in rsync.1 under --owner
>
>         On most systems, only the super-user can set file
>         ownership.  Note that if the remote system is a
>         daemon using chroot, the --numeric-ids option is
>         implied because the remote system cannot get access
>         to the usernames from /etc/passwd.
>
>And again under --numeric-ids
>
>The bases are pretty well covered.  Thanks for the thought.
>
>It just hasn't yet made it into a released version.  Once it
>is it will take a few months to get into the packaged
>distributions.
>
>
>
>--
>________________________________________________________________
>         J.W. Schultz            Pegasystems Technologies
>         email address:          jw at pegasys.ws
>
>                 Remember Cernan and Schmitt
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Regards

Riq Willitts
Technical Director
Scientific Computing Service Ltd.




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