[winswitch] Unable to connect from Windows client to RHEL 7.4 xpra server using SSH (v2.3.2-r19729)

Fri Jul 13 20:43:43 BST 2018

On 13/07/18 18:39, Ben Jackson via shifter-users wrote:
> Hi,
> 
> I'm completely new to Xpra, so please forgive me if I'm not providing the right diagnostics ;)
> 
> Quick summary:
> 
> when trying to connect xpra from Windows 7 to RHEL 7.4 over SSH, the connection fails with the following message:
> 
> 2018-07-13 12:21:02,765 Error: failed to receive anything, not an xpra server?
> 2018-07-13 12:21:02,765   could also be the wrong protocol, username, password or port
> 
> The client and server versions are the same, and the ssh connection appears to work in any other context I can try it.
> 
> Detail:
> 
> My setup is:
> - Server:
>   - RHEL 7.4
>   - Xpra 2.3.2-v19729 using the yum repo (I tried the latest 2.3.3-..., but downgraded to ensure the client/serer were same version for testing)
>   - Python 2.7.5
>   - public key in authorized_keys
> - Client:
>   - Windows 7 Pro
>   - Xpra 2.3.2-v19729 (latest MSI on website)
>   - Python 2.7.9 (not sure if the windows package uses python from my path)
It doesn't.
>  - Pageant running with private ssh key
> 
> I have installed Xpra as above and started the server successfully with "xpra start --start=xterm :1002".
Does the server respond if you run:
xpra info :1002

> However, when I attempt to connect from windows to the server using "Xpra_Cmd attach ssh://ash@ukwok-pc1385-vpc7/1002" it fails to connect and  I get the following.
> 
> 2018-07-13 12:20:59,173 Xpra gtk2 client version 2.3.2-r19729 64-bit
> 2018-07-13 12:20:59,179  running on Microsoft Windows 7
> 2018-07-13 12:20:59,363 Warning: failed to import opencv:
> 2018-07-13 12:20:59,363  DLL load failed: Invalid access to memory location.
> 2018-07-13 12:20:59,363  webcam forwarding is disabled
> 2018-07-13 12:21:00,192 GStreamer version 1.14.1 for Python 2.7.15 64-bit
> 2018-07-13 12:21:00,593 OpenGL_accelerate module loaded
> 2018-07-13 12:21:00,627 Using accelerated ArrayDatatype
> 2018-07-13 12:21:01,296 Warning: vendor 'Intel' is greylisted,
> 2018-07-13 12:21:01,296  you may want to turn off OpenGL if you encounter bugs
> 2018-07-13 12:21:01,357 OpenGL enabled with Intel(R) HD Graphics
> 2018-07-13 12:21:01,428  desktop size is 3000x1920 with 1 screen:
> 2018-07-13 12:21:01,428   Default (793x508 mm - DPI: 96x96)
> 2018-07-13 12:21:01,428     DISPLAY1 1920x1200 at 0x381 (677x423 mm - DPI: 72x72) workarea: 1920x1200
> 2018-07-13 12:21:01,428     DISPLAY2 1080x1920 at 1920x0 (381x677 mm - DPI: 72x72) workarea: 1080x1920
> 2018-07-13 12:21:01,442  keyboard settings: layout=gb
> 2018-07-13 12:21:02,765 Error: failed to receive anything, not an xpra server?
> 2018-07-13 12:21:02,765   could also be the wrong protocol, username, password or port
> 2018-07-13 12:21:02,765 Connection lost
> 
> (Full client and server log output with debug can be found in this gist: https://gist.github.com/puremourning/36d6beb1d0baefe3cb0b79ec7cbfe3dd).
> 
> The server log does not change during the process (tailing /var/user/<uid>/:1002.log).
This usually means that the xpra proxy process fails to locate the socket.

> I'm looking for some advice on how to debug this. It looks like an environment issue (xpra doesn't seem to be getting any data back from plink?), but I'm a bit stuck.
This sounds very similar to this ticket:
http://xpra.org/trac/ticket/1892
You may want to try the latest beta 2.4 build you can find.
> Some things I have tried/confirmed:
> 
> - Using unauthenticated TCP _does_ work, but is not allowable in corporate env due to infosec.
Maybe SSL mode would be allowed?
> - Using PuTTY to connect to the host works (ditto using putty's plink to echo hello). No password is required (pageant is working) (command putty\plink.exe -ssh ash at ukwok-pc1385-vpc7 echo hello). Hello is echo'd.
Can you run "xpra list" from there and see the server?
> - Using the bundled plink.exe (tortoise?) to connect to the account/host in question, no password is requested, but "hello" is *not* printed (command: plink -ssh ash at ukwok-pc1385-vpc7 echo hello)
> - Before setting up pageant (i.e. ssh-agent), all the above were tested while entering the account password manually, with the same results.
> - Using a proprietary windows x-server, I am able to connect to xpra from the server (i.e. to itself) with xpra attach. (i.e. start an xterm with display pointed at windows X server, attach to xpra, see xterm)
> 
> Many thanks for any advice you may be able to provide. Naturally if there is any further information I can provide, just shout!
>From your log output, I see that your sockets are in an unusual location:
created unix domain socket: /var/lib/ash/.xpra/ukwok-pc1385-vpc7-1002
Why is that? Is your $HOME in /var/lib ?
When connecting over ssh, CentOS fails to set XDG_RUNTIME_DIR correctly,
so this other default socket location may not be found either.
We have code to try to workaround this problem, but this makes me think
that maybe you want to try specifying --socket-dirs=/tmp at both ends to
see if that helps.

Cheers,
Antoine
> 
> Cheers,
> Ben
> 
> 
> 
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