Warning: No xauth data; using fake authentication data for X11 forwarding. (solved)

[Jerry Feldman]

On 10/15/2008 08:36 PM, Aldo Foot wrote:
> On Wed, Oct 15, 2008 at 1:48 PM, Jerry Feldman <gaf at blu.org> wrote:
>   
>> I am using Fedora 9 on an IA64 workstation. When I ssh -X to another host,
>> the ssh authentication succeeds in under a second, but the X11
>> authentication takes about 20 seconds and issues the warning:
>> Warning: No xauth data; using fake authentication data for X11 forwarding.
>>     
>
> Not sure whether this will help, but it's worth a try:
> Find out the hard coded path of the xauth binary in the sshd executable.
>   > strings `which sshd` | grep xauth
> the above command should show a line like "/usr/bin/xauth", take note
> of whatever
> path you see.
> Add a line to your /etc/ssh/sshd_config to read "XAuthLocation /usr/bin/xauth".
> Restart sshd and see what happens.
>
>   
First, the issue is NOT ssh at all. In any case, I've been 
experimenting. I was able to log out of the console. This removed the 
/var/run/auth-cookie-XXIIWBJU-for-gaf. I then logged into the server 
from my (ugh) Windows XP box with Exceed (X server) and putty. I then 
performed and 'ssh -X'. There was absolutely no delay. From the log and 
running xauth, it appears that GDM is locking the auth cookie.
[gaf at boslc01 ~]$ /usr/bin/xauth list
/usr/bin/xauth:  timeout in locking authority file 
/var/run/gdm/auth-cookie-XXIIWBJU-for-gaf

After googling on this specific message I found a solution:
1. the permission for /var/run/gdm is:
drwxr-xr-t  2 root gdm  4096 2008-10-16 08:20

2. After changing the permission to drwxrwxrwt  2 root       
gdm          4096 2008-10-16 10:14 gdm
Xauth was able to successfully establish the lock. I checked my home 
Fedora9 system and it was set to drwxrwxrwt.

So, I think the problem is with the Fedora 9 installation on  IA64.

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
PGP key id: 537C5846
PGP Key fingerprint: 3D1B 8377 A3C0 A5F2 ECBB  CA3B 4607 4319 537C 5846


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