Bug 52953

Summary:	On a diskless workstation X server doesn't set correct permissions to unix socket
Product:	[Retired] Red Hat Linux	Reporter:	Gabriele Turchi <turchi>
Component:	kernel	Assignee:	Arjan van de Ven <arjanv>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Brock Organ <borgan>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	9	CC:	mharris
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2003-06-06 18:12:58 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Gabriele Turchi 2001-08-31 11:03:50 UTC

Description of Problem:

On a diskless workstation (the root file system is mounted from a
roswell-based system with v3,nolock,rsize=8192,wsize=8192 flags) the X
server leave its unix socket (/tmp/.X11-unix/X0) with permissions 0755, and
only root-owned client can connect. If I do a chmod 777 by hand, the normal
behaviour is back. I've done a test mounting a nbd (network block device)
file system under tmp, and the normal behaviour reappeared. This appear as
a bug in nfs/knfsd code.
I've also tryed to mount a different nfs file system as tmp, with flags as
lock or noac, but nothing changed. The kernel running on the diskless
worstation is a standard (redhat) 2.4.6 kernel for i686 with compiled in
the network module (8139too) and the nfs client module, with nfs root
option enabled.
Gabriele Turchi

P.S.: My english is alpha version...

Version-Release number of selected component (if applicable):
kernel 2.4.6 redhat

How Reproducible:
Every time

Steps to Reproduce:
1. Configure a diskless workstation
2. login as normal user
3. startx 

Actual Results:
X will start, but no application is started

Expected Results:
normal X session (gnome, in my case) startup

Additional Information:

Comment 1 Mike A. Harris 2001-09-01 19:58:33 UTC

no-root-squash?

Comment 2 Gabriele Turchi 2001-09-03 06:33:29 UTC

Standard flags for a nfs root are obviously rw and no_root_squash. Apparently
any other service (as writing the mtab in /etc) runs well (xfs too).

Gabriele Turchi

Comment 3 Gabriele Turchi 2001-09-03 11:32:14 UTC

Some more test done. I've updated the kernel on the diskless client to vanilla
2.4.9 without results, but the problem disappeared updating the server kernel to
the same vanilla (with jbd/ext3 patches only). (The original kernel was 2.4.6-3.1)

Gabriele Turchi

Comment 4 Mike A. Harris 2002-02-05 17:23:31 UTC

This sounds more like a kernel NFS issue than an XFree86 issue.

Does it occur with our current RHL 7.2 erratum kernel 2.4.9-21?

Comment 5 Gabriele Turchi 2002-02-08 09:28:34 UTC

Apparently not. 

I'm using a kernel 2.4.9-21 recompiled using standard athlon config file with
added NFS root file system support and tulip, sis900 and rtl8139 drivers built in.

Comment 6 Mike A. Harris 2002-02-08 19:43:48 UTC

Just to confirm what you mean - aparently not what?

Does 2.4.9-21 work as supplied in binary form by Red Hat?

Comment 7 Alan Cox 2002-02-08 19:49:05 UTC

Our base kernel doesn't have NFS root so that is tricky to get him to check. I
agree it looks like a kernel issue. Firstly its a wonder it works at all because
AF_UNIX sockets are not defined over NFS 8)

The traditional workaround is to use localhost:0 as the socket.

Nevertheless I'd like to know why it failed. Is this reproducable on a
conventional box with /tmp NFS mounted.

Comment 8 Gabriele Turchi 2002-02-10 12:00:45 UTC

I'm sorry, I've done a mistake. As I wrote in my first posting, the problem
appear to belongs to 2.4.6 kernel (roswell) knfsd. With different kernel on the
server (2.4.9 vanilla or RedHat) the problem vanished.

My last test was to upgrade _client_ kernel as described, but the server was
updated to standard RedHat 7.2 some months ago (without any problem).

Now, I think the right answer to Harris question is: the problem doesn't occour
with standard 7.2 kernel.


Alan, I don't know what to think: ls say that (on the server)

  [root@roccia dl01]# ls -la tmp/.X11-unix/X0 
  srwxrwxrwx    1 root     root            0 feb 10 12:32 tmp/.X11-unix/X0

and on the client:

  [root@dl01 root]# ls -la /tmp/.X11-unix/X0 
  srwxrwxrwx    1 root     root            0 feb 10 12:32 /tmp/.X11-unix/X0