chroot and wrong user names

jw schultz jw at pegasys.ws
Thu Sep 19 09:43:01 EST 2002


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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