x2go-dev April 2020

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18 participants
92 discussions

Bug#1465: Allow running with restricted shell (rbash), or limit applications that can be run.
by Vladislav Kurz 04 May '20

04 May '20

Package: x2goserver Version: 4.1.0.3-0~1708~ubuntu16.04.1 Severity: wishlist Hello all, we are using x2go to run a single application on remote server, and we want to lock all other access as much as possible. Essentially, we'd like to ensure that even if the user connects via SSH, he could start only one (or limited set) of applications. I found this guide https://wiki.x2go.org/doku.php/wiki:security:rbash but it seems to be somewhat outdated. I followed the instructions, created the wrapper command, set up the symlinks, and configured ssh, but then I get this error: Connection failed. rbash: bash: command not found Apparently x2go client is trying to execute "bash /usr/bin/x2goruncommand" instead of just "x2goruncommand". If I add bash to the path with allowed commands, it starts working. But it makes the whole use of rbash pointless. Also it allows me to run anything via x2go anyway - as x2goruncommand is a bash script, it escapes the restrictions of rbash. Is it possible to update that wiki page with current requirements - what commands are necessary in $PATH for restricted shell ? I found that at least nxagent should be there too. And to modify the login sequence so that bash is not needed in $PATH ? BTW is that defined on server or client? Where exactly? I also found a nice feature "published applications" https://wiki.x2go.org/doku.php/wiki:advanced:published-applications It would be nice, if the x2go server had a config option, allowing users to run only the "published applications", or use some other list of allowed commands. So far my attempts at limiting the access to other applications was not very successful. There's a lot of stuff needed internally by x2go, so I cannot just remove execute bit from many commands in (/usr)/bin/ Thanks for any advice or hotfix. Best Regards Vladislav Kurz

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Bug#1454: Better explain fullscreen keyboard shortcuts usage on multi display setup
by Olivier Gauthier 04 May '20

04 May '20

Package: wiki.x2go.org Add missing keyboard shortcut Shift + Ctrl + Alt + F to x2goclient documentation. I spent an hour trying to figure why my X2Go session would not want to go fullscreen over all my screens like I normally do. I realized I always used Ctrl + Alt + F to go fullscreen as explained at https://wiki.x2go.org/doku.php/doc:usage:x2goclient. That gave me fullscreen session spanning over all multi display screens as expected. However, without noticing it, I started using Shift + Ctrl + Alt + F this morning because my muscle memory have been trained while using Guacamole menu shortcut (uses Shift-Ctrl-Alt keys to toggle menu). I did not notice at first, because Shift + Ctrl + Alt + F also works on X2Go Client, but it only go fullscreen on current display screen. It puzzled me for a while today, so I went back to wiki page, to figure I have been using wrong shortcut. I verified code for key bindings (https://code.x2go.org/gitweb?p=nx-libs.git;a=blob;f=etc/keystrokes.cfg;hb=H…) and it effectively offers two clever options to go full screen on multi displays. > 4 <keystroke action="switch_all_screens" Control="1" AltMeta="1" key="f" /> > 5 <keystroke action="fullscreen" Control="1" Shift="1" AltMeta="1" key="f" /> Here is two wiki patches to help clarify documentation around full screen usage on multi display setups. Feel free to rephrase any way you want. -- Olivier -- doc/usage/x2goclient.txt 70c70,71 < * Ctrl + Alt + F: toggle fullscreen/windowed --- > * Ctrl + Alt + F: toggle windowed/fullscreen over all screens > * Shift + Ctrl + Alt + F: toggle windowed/fullscreen on current screen only doc/usage/multi-display.txt 19a20,26 > > ===== Use keyboard shortcuts to go fullscreen over one or all displays ===== > > There is two different ways to enter fullscreen from keyboard shortcuts. One goes fullscreen over all screens, the other goes fullscreen only on current screen. > > * Ctrl + Alt + F: toggle windowed/fullscreen over all screens > * Shift + Ctrl + Alt + F: toggle windowed/fullscreen on current screen only

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Bug#1450: Fwd: Arrow keys randomly stop working in x2go
by stivstivsti . 03 May '20

03 May '20

Package: x2goclient Version: 4.1.2.2 I am connecting from Ubuntu Linux 18 to another Ubuntu linux machine with x2go. Connection works, but some keys don't, especially arrow keys. When I press up arrow, it starts screen capture: [image: image.png] I tried some recipes from this question: https://serverfault.com/questions/582552/x2go-arrow-key-is-not-working-prop… but they don't help. *setxkbmap us -print | xkbcomp - $DISPLAY* -- doesn't fix the problem. I tried to play with keyboard settings here: [image: image.png] but it doesn't help also. How can I fix it? I've followed instruction from wiki.x2go.org updating x2goclient to 4.1.2.2-0~1913~ubuntu18.04.1 and x2goserver to 4.1.0.3-0~1708~ubuntu18.04.1. The problem is still there.

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Bug#1456: Local window manager misbehaves when X2Go windows are open.
by Itay Chamiel 01 May '20

01 May '20

Package: x2goclient Version: 4.1.2.2 or 4.1.1.1 Environment: Client: Ubuntu 18.04 LTS, 64-bit, freshly installed and fully updated, running X2Go Client v. 4.1.2.2 (Qt - 4.8.7). Machine is a Dell Vostro 15 3000 laptop, with an external monitor connected and the lid shut. Server OS: Ubuntu 16.04.1 LTS, x2goserver 4.1.0.3 Steps to reproduce: 1. Start with a typical local desktop session (tested on default Ubuntu desktop as well as Cinnamon), with at least one window open (say, a web browser or email client). 2. In X2Go define a session: set the session name, host, login, check "try auto login". Session type: Single application, choose "Terminal" from the drop-down. 3. Start this session. X2Go will connect and a "Konsole" window will appear. [note: if you get a different terminal, go back to step 2 and type "konsole" as the requested remote application. Konsole is not the only terminal to exhibit this bug but is the easiest to reproduce it with.] 4. Type something in the terminal, "hello", whatever. 5. Now try to switch to another window using Alt-Tab or clicking on the task bar icon representing that window. When I perform these steps the requested window does not appear and the Konsole remains on top and in focus. The only way to return to normal behavior is to minimize the Konsole window.

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Bug#1466: x2gokdriveclient not packaged for windows
by Михайло Падалка 24 Apr '20

24 Apr '20

Package: x2goclient Version: 4.1.2.2 X2GoClient installer for windows has no x2gokdriveclient.exe packaged, but has an option "Run in X2GoKDrive (experimental)" available. That's at least confusing, as it will never work. Either x2gokdriveclient should be packaged (preffered, as X2GoKDrive works better for modern desktops), or that option should be not available on Windows.

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Bug#1458: unattended Debian installations (using preseed) fail when x2gobroker-ssh is involved
by Stefan Baur 21 Apr '20

21 Apr '20

package: x2gobroker-ssh version 0.0.4.1 severity: important The postinst file for x2gobroker-ssh contains a check to see if the nscd binary is somewhere in the path. If it is, then nscd -i group is called, to purge the group cache (which makes sense, as a new group has been added in a previous step, so the cached information is outdated). If it is not, then it is assumed that nscd is not installed, thus, no group information is cached, and thus, no purge is needed. This fails to take into account that nscd might be (freshly) installed, but not running. Which is the case during a preseeded Debian installation (and probably when running debootstrap as well). The result is that "nscd -i group" is called even though nscd isn't active at the moment. Which triggers a return code of "1". Which in turn causes the postinst script to report "1" as its return code. This, of course, gets passed back up to the debian-installer, which decides to abort the installation, as it seems that something went wrong during installation of the package. The patch is rather simple: Instead of checking for the presence of the executable in the file system, check if it is currently running: - if which nscd 1>/dev/null; then + if ps -C nscd 1>/dev/null; then As this is currently breaking all automated x2gobroker-ssh installs, I would suggest releasing a new version containing only this patch ASAP, if a full release with all changes since the last proper release of x2gobroker-ssh would bring too many changes at once for a timely release. Kind Regards, Stefan Baur -- BAUR-ITCS UG (haftungsbeschränkt) Geschäftsführer: Stefan Baur Eichenäckerweg 10, 89081 Ulm | Registergericht Ulm, HRB 724364 Fon/Fax 0731 40 34 66-36/-35 | USt-IdNr.: DE268653243

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Processed: Re: Bug#1460: Acknowledgement (Windows client crashes if Jumphost runs NetBSD 6 (probably race))
by X2Go Bug Tracking System 21 Apr '20

21 Apr '20

Processing commands for control(a)bugs.x2go.org: > reassign 1460 x2goclient 4.1.2.2 Bug #1460 [x2go-client for windows] Windows client crashes if Jumphost runs NetBSD 6 (probably race) Warning: Unknown package 'x2go-client' Warning: Unknown package 'for' Warning: Unknown package 'windows' Bug reassigned from package 'x2go-client for windows' to 'x2goclient'. No longer marked as found in versions 4.1.2.2. Ignoring request to alter fixed versions of bug #1460 to the same values previously set Bug #1460 [x2goclient] Windows client crashes if Jumphost runs NetBSD 6 (probably race) There is no source info for the package 'x2goclient' at version '4.1.2.2' with architecture '' Unable to make a source version for version '4.1.2.2' Marked as found in versions 4.1.2.2. > End of message, stopping processing here. Please contact me if you need assistance. -- 1460: bugs.x2go.org/cgi-bin/bugreport.cgi?bug=1460 X2Go Bug Tracking System Contact owner(a)bugs.x2go.org with problems

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Bug#1459: X2GoMiniSSHBroker
by Stefan Baur 20 Apr '20

20 Apr '20

package: x2gobroker priority: wishlist Hi everyone, A while ago, I wrote a small broker demo in bash. I would like to get this added to X2Go's official repository, in the x2gobroker.git tree, as a separate binpkg (maybe called x2gobroker-ssh-mini). Limitations: 1) This script is not suitable for a multi-server setup. It needs to run on the only X2GoServer there is. (There's an idea in the comments how to overcome this limitation, though.) This is, however, also its advantage: You don't need to mess with LDAP, postgres and NFS just to be able to use a central configuration for your X2GoClients. 2) It does not offer all the ACL options of the "big" broker implementations. Problems: 1) There's currently no manpage for it. All documentation is in the comments in the bash script. 2) IIRC, Alex made some changes to X2GoClient and/or X2GoServer that will cause this script to break - however, these changes are not part of our stable release yet. So it should be possible to release this package right now, but it needs to be kept in mind that it will have to be adapted once Alex' changes make it to stable. This was related to more "chatter" about "Access granted" and similar status messages being exchanged between server/broker/client. Script attached. Kind Regards, Stefan Baur -- BAUR-ITCS UG (haftungsbeschränkt) Geschäftsführer: Stefan Baur Eichenäckerweg 10, 89081 Ulm | Registergericht Ulm, HRB 724364 Fon/Fax 0731 40 34 66-36/-35 | USt-IdNr.: DE268653243

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Bug#1460: Windows client crashes if Jumphost runs NetBSD 6 (probably race)
by Edgar Fuß 19 Apr '20

19 Apr '20

Package: x2go-client for windows Version: 4.1.2.2 The Windows X2Go client crashes (in ntdll.dll) if the Jumphost is running NetBSD 6 (it works for NetBSD 8). It crashes so early in the SSH negotiation that no further details (authentication type etc.) are relevant. Now, NetBSD 6 (and OpenSSH 5.9, which it uses) are pretty obsolete, but interestingly, the client does not crash if run under logger.exe, so this looks like a race. Installing OpenSSH 8.0 (from pkgsrc) on the NetBSD 6 Jumphost doesn't help. I verified that insatlling OpenSSH 8.0 on a NetBSD 8 host (which natively uses OpenSSH 7.6) works. So it's not just the OpenSSH version that matters. But, if the Jumphost runs OpenSSH 8.0 on NetBSD 6 (where the client crashes unless run under logger.exe), tcpdump-ing the SSH connection on the Jumphost makes the client work. If I additionally tcpdump on the client side (more precisely, on the macOS system hosting the VirtualBox VM running MS Win), the client crashes again. It looks like the condition that triggers the crash may be the client receiving the Server Key Exchange Init _after_ it sent the Client Key Exchange Init. The packet sequence involved is (I/O as seen on the Jumphost, i.e. I client->server and O server->client): 1 I SYN (ECN, CWR) 2 O SYN/ACK 3 I ACK 4 I Client: Protocol 5 O Server: Protocol 6 I ACK running tcpdump on NetBSD only (works): 7 O Server: Key Exchange Init 8 I ACK 9 I Client: Key Exchange Init 10 I Client: Diffie-Hellman Key Ecxhange Init 11 O ACK 12 O Diffie-Hellman Key Exchange Reply 13 I ACK 14 I Client: New Keys 15 I Client: Encrypted Packet ... running tcpdump on NetBSD and macOS (client crashes), as seen on the NetBSD side: 7 O Server: Key Exchange Init 8 I Client: Key Exchange Init 9 I ACK 10 I Client: Diffie-Hellman Key Exhange Init 11 O ACK 12 O Diffie-Hellman Key Exchange Reply 13 I ACK 14 I Client: New Keys 15 O ACK 16 I FIN/ACK same as seen on the macOS side: 7 I Client: Key Exchange Init 8 O Server: Key Exchange Init [rest looks as on the NetBSD side] Any hints how to debug this? I know virtually nothing about MS Win.

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Bug#1447: x2godesktopsharing termination
by Oleg Solovyov 10 Apr '20

10 Apr '20

Package: x2godesktopsharing Version: 3.2.0.0 Severity: grave When connecting from machine A to machine B, x2godesktopsharing running on B, exits normally instead of changing its tray icon to view.png ALT Workstation 9, using MATE with kernel 4.19.79-std-def-alt1

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x2go-dev April 2020