Subject: Bug#31: X2Go Clients Gr-Tunnel (client-side endpoint) listens on all TCP/IP address (probably should be: loopback only)

From: Mike Gabriel <[email-masked]>
Date: Mon, 17 Sep 2012 16:43:00 +0200

Package: x2goclient
Severity: normal
Version: 3.99.3.0-prerelease

Hi all,

I just stumbled over an issue that we maybe have to address. Probably  
in X2Go Client, I guess.

X2Go Client launches nxproxy and netstat -ap delivers this output:

"""
tcp        0      0 *:31004                 *:*                      
LISTEN      20139/x2goclient
                      
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
tcp        0      0 *:16001                 *:*                      
LISTEN      6822/pulseaudio
tcp        0      0 *:4713                  *:*                      
LISTEN      6822/pulseaudio
tcp        0      0 localhost:44610         localhost:ssh            
VERBUNDEN   20139/x2goclient
tcp        0      0 localhost:44609         localhost:ssh            
VERBUNDEN   20139/x2goclient
tcp        0      0 localhost:45257         localhost:31004          
VERBUNDEN   20161/nxproxy
tcp        0      0 localhost:31004         localhost:45257          
VERBUNDEN   20139/x2goclient
tcp        0      0 localhost:31004         localhost:45257          
VERBUNDEN   20139/x2goclient
tcp6       0      0 [::]:16001              [::]:*                   
LISTEN      6822/pulseaudio
tcp6       0      0 [::]:4713               [::]:*                   
LISTEN      6822/pulseaudio
"""

PyHoca-GUI with Python X2Go in its back, however, deliveres this  
output with netstat -p:

"""
tcp        0      0 localhost:30004         *:*                      
LISTEN      20728/pyhoca-gui
tcp        0      0 *:16001                 *:*                      
LISTEN      6822/pulseaudio
tcp        0      0 *:4713                  *:*                      
LISTEN      6822/pulseaudio
tcp        0      0 localhost:30004         localhost:52107          
VERBUNDEN   20728/pyhoca-gui
                      
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
tcp        0      0 m-110.informatik.:41910 fylgja.das-netzwe:32032  
VERBUNDEN   20728/pyhoca-gui
tcp        0      0 localhost:52107         localhost:30004          
VERBUNDEN   20773/nxproxy
tcp6       0      0 [::]:16001              [::]:*                   
LISTEN      6822/pulseaudio
tcp6       0      0 [::]:4713               [::]:*                   
LISTEN      6822/pulseaudio
"""

Output with lsof -i is even more weird, as lsof -i shows that nxproxy  
is listening on all
TCP/IP addresses, not X2Go Client.

"""
nxproxy    9514 mike    5u  IPv4 321255      0t0  TCP  
localhost:44690->localhost:31004 (ESTABLISHED)
nxproxy    9514 mike   12u  IPv4 321189      0t0  TCP  
m-110.informatik.uni-kiel.de:41258->fylgja.das-netzwerkteam.de:32032  
(ESTABLISHED)
nxproxy    9514 mike   13u  IPv4 321239      0t0  TCP *:31004 (LISTEN)
nxproxy    9518 mike   12u  IPv4 321189      0t0  TCP  
m-110.informatik.uni-kiel.de:41258->fylgja.das-netzwerkteam.de:32032  
(ESTABLISHED)
nxproxy    9518 mike   13u  IPv4 321239      0t0  TCP *:31004 (LISTEN)
"""

Greets,
Mike

-- 

DAS-NETZWERKTEAM
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