[LightDM] Magic cookie doesn't work - no protocol specified

[Robert Ancell]

I just really wanted the .Xauthority files to check that they contain the
cookies in the format we expected.

On Thu, 19 Nov 2015 at 03:03 Mikhail Morfikov <mmorfikov at gmail.com> wrote:

> On 2015-11-18 06:17, Robert Ancell wrote:
> > Hi Mikhail,
> >
> > It's hard to tell exactly what is wrong - if you attach both .Xauthority
> > files it will be easier to see the difference.
> >
> > Check what version of Xorg you are running and check it is actually
> > enabling TCP connections - there was a behaviour change in X [1].
> >
> > --Robert
> >
> > [1] https://launchpad.net/bugs/1449282
> >
> >
> > On Fri, 30 Oct 2015 at 16:45 Mikhail Morfikov <mmorfikov at gmail.com>
> wrote:
> >
> >> When I start an X-session via startx on my debian distro, I can get the
> >> output of the two following commands:
> >>
> >> $ xauth extract - $DISPLAY
> >> morfikownia0MIT-MAGIC-COOKIE-1’E!ö½o`q!SD„%
> >>
> >> $ xauth extract - morfikownia.mhouse.lh:0.0
> >> À¨–0MIT-MAGIC-COOKIE-1­Ê¹2y0ºˆ%
> >>
> >> I know that the output is a little unreadable, but the most important
> >> thing is that I get the output from the two commands above. When I send
> >> that cookie to another machine using this command:
> >>
> >> $ xauth extract - morfikownia.mhouse.lh:0.0 | ssh -x
> morfik at 192.168.10.20
> >> xauth merge -
> >>
> >> I can get access to this X-server from that machine, and everything
> works
> >> as expected.
> >>
> >> When I start am X-session via LightDM, the command:
> >>
> >> xauth extract - morfikownia.mhouse.lh:0.0
> >>
> >> returns nothing, or actually it gives me the following message:
> >>
> >> "No matches found, authority file "-" not written"
> >>
> >> I can, of course, use the following command to get the cookie:
> >>
> >> xauth extract - $DISPLAY
> >>
> >> and then send it via:
> >>
> >> $ xauth extract - $DISPLAY | ssh -x morfik at 192.168.10.20 xauth merge -
> >>
> >> But in that case, when I try to connect remotely to this X-server, I'm
> >> unable to do it. I get a message that "no protocol specified", and
> nothing
> >> happens.
> >>
> >> I think I have the exact same options set in both cases, i.e. in the
> >> /etc/X11/xinit/xserverrc file I have the following line:
> >>
> >> exec /usr/bin/X -auth "$HOME/.Xauthority" -listen tcp "$@"
> >>
> >> And in the case of LightDM I have these options set in its config file
> >> (/etc/lightdm/lightdm.conf):
> >>
> >> egrep -v ^# /etc/lightdm/lightdm.conf
> >> [LightDM]
> >> greeter-user=lightdm
> >> minimum-display-number=0
> >> minimum-vt=7
> >> logind-check-graphical=true
> >> log-directory=/var/log/lightdm
> >> run-directory=/var/run/lightdm
> >> cache-directory=/var/cache/lightdm
> >>
> >> [Seat:*]
> >> xserver-command=X -listen tcp -auth "$HOME/.Xauthority"
> >> xserver-allow-tcp=true
> >> greeter-session=lightdm-gtk-greeter
> >> greeter-hide-users=false
> >> greeter-allow-guest=false
> >> greeter-show-manual-login=true
> >> greeter-show-remote-login=true
> >> user-session=openbox
> >> allow-user-switching=true
> >> allow-guest=false
> >> autologin-guest=false
> >> autologin-user-timeout=0
> >> autologin-in-background=false
> >>
> >> [XDMCPServer]
> >>
> >> [VNCServer]
> >>
> >> Do you know why it fails to connect to the X-server when LightDM is
> used?
> >> Is there a way to fix it?
> >> _______________________________________________
> >> LightDM mailing list
> >> LightDM at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/lightdm
> >>
> >
> I know that the default behavior of X-server changed in some version, but
> I managed to set the server without any problem, and it was working when
> started via "startx". You can see the settings that was set in the
> /etc/lightdm/lightdm.conf file, and they were exactly the same as those
> in the /etc/X11/xinit/xserverrc file. The problem was somewhere in "xauth
> extract" because this command was working fine with "startx", but it
> didn't work well with lightdm.
>
> > It's hard to tell exactly what is wrong - if you attach both .Xauthority
> > files it will be easier to see the difference.
>
> I sent that message some weeks ago, and I don't have that setup anymore.
> I could try to make another one, but you have to tell me if you want me
> to issue some particular commands, or you want me to attach the full
> .Xauthority files from both machines?
>
>
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