setuid program don't run from NFS mounted filesystems

setuid program don't run from NFS mounted filesystems

Post by Andreas Schuman » Sun, 06 Jul 1997 04:00:00



I'm running Redhat Linux 4.2 on Intel machines.

I installed Redhat Linux 4.2 on my home computer on local filesystems.
Then I brought the same computer to the lab and tried to mount it to the
existing network via NFS.

However, I cannot run any programs with the setuid permission flag set
from the NFS mounted drives. My exports file on my server should be ok,
it runs with all the other machines, and I extended it to include the
hostname of the new machine. Do I have to give permissions somewhere on
the NFS-server so that the client can run setuid programs?

Thanks for any help.

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setuid program don't run from NFS mounted filesystems

Post by mar.. » Tue, 08 Jul 1997 04:00:00


There are usually two places where this could be set (I think)
On the server, you can specify that suid-bits get squashed, or on the client.
/etc/exports

Parameters like: (...insecure,all_squash...) kill permissions a bit.

/etc/fstab

Here you need a line like:
remote-machine:/        /mnt    nfs     defaults,user,exec,suid,noauto 1 1 (or something similar)

Take note, that some OSs ignore suid-bits on scripts...

Cheers,
Marius.
-- Marius van Wyk

-- Tangible Business Software

 
 
 

setuid program don't run from NFS mounted filesystems

Post by Pat Thoyt » Tue, 08 Jul 1997 04:00:00



> I'm running Redhat Linux 4.2 on Intel machines.

> I installed Redhat Linux 4.2 on my home computer on local filesystems.
> Then I brought the same computer to the lab and tried to mount it to the
> existing network via NFS.

> However, I cannot run any programs with the setuid permission flag set
> from the NFS mounted drives. My exports file on my server should be ok,
> it runs with all the other machines, and I extended it to include the
> hostname of the new machine. Do I have to give permissions somewhere on
> the NFS-server so that the client can run setuid programs?

> Thanks for any help.

How about a copy of the /etc/exports file and what you're typing in (or
your fstab entry) to mount it?

You perhaps have something like:
/usr/public my.host.net(rw)

man exports has this to say (under User ID Mapping):
       Very  often,  it  is not desirable that the root user on a
       client machine is also  treated  as  root  when  accessing
       files  on  the  NFS server. To this end, uid 0 is normally
       mapped to a  different  id:  the  so-called  anonymous  or
       nobody  uid.  This mode of operation (called `root squash-
       ing')  is  the  default,  and  can  be  turned  off   with
       no_root_squash.

So you need to try (rw, no_root_squash).

The man page should sort it
--
Pat Thoyts                       Remove anti-spam from address to reply.
Tel: +44-(0)-1275-549414  http://pc0652.lars.bbsrc.ac.uk/~pat/home.shtml

 
 
 

1. NFS filesystems don't mount at system start

Using: RH6.2 and a Snap! file server.

We want to mount an NFS filesystem at system startup, and have the
following entry in /etc/fstab:

snap2:/apps /apps/snap nfs defaults 0 0

(Note, we have replaced 'defaults' with 'auto,defaults' as a test
already.) When the system boots the NFS filesystem is not mounted. I
have to do:

# mount -t nfs -a

In order to mount it. We need this filesystem mounted before some
other applications try to startup during system start, and so rc.local
doesn't look like a good solution.

I have confirmed that netfs is running:


netfs           0:off   1:off   2:off   3:on    4:on    5:on    6:off

What do I need to do to get this filesystem mounted when the system
boots?

Regards, Dustin

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