[comp.unix.wizards] rsh and nfs home directory

jgd@pollux.UUCP (Dr. James George Dunham) (06/29/88)

	We are running 4.3 + NFS from Mt. Xinu on some 750's and uVAX-II.
I recently split up the /usr2 (user) file system across machines and 
then used NFS to network then together as a single /usr2 directory. I
have discovered a problem when a regular user attempts to do a remote
command to a machine where his home (login) directory is on an NFS
mounted directory, i.e., another machine physically has his files. The
command fails with "permission denied". Further background is that root
does not have superuser priviliges on NFS mounted file systems. The
machines are set to run with each other being an equivalent host. The
problem appear with and without yellow pages running. Further, the
user has a .rhosts file with the other machine given permission to
execute remote commands. I admit I have not spent much time digging
into the problem, but perhaps someone else has observed the problem
and can provide a solution. Thanks for any help.
				-Jim Dunham
				 pollux!jgd

david@pyr.gatech.EDU (David Brown) (06/29/88)

In article <10730@pollux.UUCP> jgd@pollux.UUCP (Dr. James George Dunham) writes:
>
>	We are running 4.3 + NFS from Mt. Xinu on some 750's and uVAX-II.
>...Further background is that root
>does not have superuser priviliges on NFS mounted file systems. The
>machines are set to run with each other being an equivalent host.

>				-Jim Dunham
>				 pollux!jgd

I think you need to change the kernel variable 'nobody' in order to allow
superuser access over the network.  There are several ways to do this, so I
won't delve into them here.  Look at the Sun manuals ("System Administration",
under "Sun Network Services").  Hope this helps.

                -David Brown


-----------------------------------------------------------------------------
David Brown
Armstrong State College, Savannah, Georgia
uucp: ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!david
ARPA: david@pyr.gatech.edu

mike@turing.unm.edu (Michael I. Bushnell) (06/29/88)

In article <10730@pollux.UUCP> jgd@pollux.UUCP (Dr. James George Dunham) writes:
>
>	We are running 4.3 + NFS from Mt. Xinu on some 750's and uVAX-II.
>I recently split up the /usr2 (user) file system across machines and 
>then used NFS to network then together as a single /usr2 directory. I
>have discovered a problem when a regular user attempts to do a remote
>command to a machine where his home (login) directory is on an NFS
>mounted directory, i.e., another machine physically has his files. The
>command fails with "permission denied". Further background is that root
>does not have superuser priviliges on NFS mounted file systems. The
>machines are set to run with each other being an equivalent host. The
>problem appear with and without yellow pages running. Further, the
>user has a .rhosts file with the other machine given permission to
>execute remote commands. I admit I have not spent much time digging
>into the problem, but perhaps someone else has observed the problem
>and can provide a solution. Thanks for any help.
>				-Jim Dunham
>				 pollux!jgd



First off, root (by default) does not have root on remote machines,
instead, uid 0 is mapped to "nobody" (defined in nfs/nfs_server.c),
which is -2 by default.  If you trust everyone who you export to, and
everyone who is root on your network and clever, then you can set this
to 0, and your problem goes away.

Failing that, the problem seems to be that the remote machine is
unable (as root) to read the users .rhosts file.  Solution:  tell all
your users to make their home directories publicly searcheable (if not
readable) and their .rhosts file to be publicly readable.

hosts.equiv has no bearing on the mapping of 0 to nobody by the nfs
server.



-- 
                N u m q u a m   G l o r i a   D e o 

			Michael I. Bushnell
			HASA - "A" division
			mike@turing.unm.edu
	    {ucbvax,gatech}!unmvax!turing.unm.edu!mike