[X2Go-Dev] Bug#272: [X2Go-User] Session resume fails with AFS home directories

[Sebastian Flothow]

Am 26.07.2013 16:40, schrieb Mike Gabriel:
> Package: x2goserver
> Version: 4.0.1.3

By now it's 4.0.1.6-0~x2go1+wheezy~main~712~build1, but the problem 
persists.


> Is there any environment variable that we have to set before we can
> access the home directory of the user?
>
> My guess is that we have to set at least
>
>    export KRB5CCNAME=???
>
> Maybe any other env var for the AFS token?

No, that should not be necessary. KRB5CCNAME is set by pam_krb5.so. 
pam_afs_session.so in turn uses this to obtain an AFS token, then 
associates it with a new Process Authentication Group. The PAG ID is 
stored in the group array for the session, i.e. "id" shows an additional 
artificial group id. In fact this all works flawlessly on initial login, 
it's only on resume where it fails.

It occurs to me now that both KRB5CCNAME and PAG are per-session rather 
than per-user, so that might be the cause for this problem (but I'm 
really just guessing here).

Is there a detailed description of the resume process? Does it involve 
any shell scripts or similar I could hook into in order to log 
additional information?


I'm attaching /var/log/user.log as well as the client output from a 
failed resume attempt, maybe this offers some clues.

Thanks,
Sebastian
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ONMainWindow constructor 

primary screen geometry:  QRect(0,0 1280x1024) 
ONMainWindows constructor finished, home Directory is: "/afs/gip.local/home/flothow" 

read  2  sessions from config file 
start new ssh connection to server: "login1.gip.local" : "22" krb:  false 

ssh connection ok 

continue normal x2go session 

executing remote command:  "sh -c "export HOSTNAME && x2golistsessions"" 

executing remote command:  "sh -c "x2goresume-session flothow-50-1375090659_stDGNOME_dp24 800x600 adsl 16m-jpeg-9 de pc105/de 1"" 

Agent output: "gr_port=30001
sound_port=30002
fs_port=30003
" 
new gr_port:  "30001" 

new sound_port:  "30002" 

new fs_port:  "30003" 

starting nxproxy with:  "nxproxy -S nx/nx,options=/afs/gip.local/home/flothow/.x2go/S-flothow-50-1375090659_stDGNOME_dp24/options:50" 

"
NXPROXY - Version 3.2.0

Copyright (C) 2001, 2007 NoMachine.
See http://www.nomachine.com/ for more information.

Info: Proxy running in client mode with pid '4536'.
Session: Starting session at 'Mon Jul 29 11:42:01 2013'.
Info: Connecting to remote host 'localhost:31001'.
Info: Connection to remote proxy 'localhost:31001' established.
" 

search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
"Channel Schreibfehler"  -  "Remote channel is closed" 

"Error: The remote NX proxy closed the connection.
Error: Failure negotiating the session in stage '7'.
Error: Wrong version or invalid session authentication cookie.
Session: Terminating session at 'Mon Jul 29 11:42:02 2013'.
Session: Session terminated at 'Mon Jul 29 11:42:02 2013'.
" 

deleting proxy 

nxproxy not running 

proxy deleted 

check command message 

executing remote command:  "sh -c "x2gocmdexitmessage flothow-50-1375090659_stDGNOME_dp24"" 

"channel_open_session schlug fehl" :  "Writing packet: error on socket (or connection closed): Die Operation ist jetzt in Bearbeitung" 

search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
search proxy win:  "X2GO-flothow-50-1375090659_stDGNOME_dp24" 
close event 
saving settings 
done 
waiting sshConnection to finish
 
sshConnection is closed
 
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