Connecting to the same session fails [VNC error - problem connecting]

[Saya47]

Hello! I hope you're having a great time.

I've added this small config to the bottom of /etc/xrdp/xrdp.ini:

[xrdp1]
name=mysession
lib=libvnc.so
username=ask
password=ask
ip=127.0.0.1
port=ask-1

I've logged in locally on my laptop but I want to connect remotely to it now, but it fails:

VNC error - problem connecting
some problem
Error connecting to the user session

cat /var/log/xrdp.log

[WARN ] Ignoring obsolete SCP port value '3350'
[INFO ] xrdp_wm_log_msg: sesman connect ok
[INFO ] xrdp_wm_log_msg: Performing login request for shayan
[INFO ] xrdp_wm_log_msg: login was successful - creating session
[INFO ] xrdp_wm_log_msg: session is available on display 14 for user shayan
[INFO ] xrdp_wm_log_msg: Connecting to session
[INFO ] loaded module 'libvnc.so' ok, interface size 4064, version 4
[ERROR] VNC error 1 after security negotiation
[ERROR] VNC error before sending share flag
[ERROR] VNC error before receiving server init
[ERROR] VNC error before receiving pixel format
[ERROR] VNC error before receiving name length
[ERROR] VNC error before receiving name
[ERROR] xrdp_wm_log_msg: Error connecting to user session

cat /var/log/xrdp-sesman.log

[WARN ] Timed out waiting for X server on display 14 to startup
[INFO ] Session started successfully for user shayan on display 14
[INFO ] Starting the xrdp channel server for display 14
[INFO ] Session in progress on display 14, waiting until the window manager (pid 500981) exits to end the session
[WARN ] Timed out waiting for X server on display 14 to startup
[ERROR] There is no X server active on display 14
[ERROR] A fatal error has occurred attempting to start the window manager on display 14, aborting connection
[WARN ] Window manager (pid 500981, display 14) exited quickly (0 secs). This could indicate a window manager config problem
[INFO ] Calling auth_stop_session from pid 500980
[INFO ] Terminating X server (pid 500982) on display 14
[INFO ] Terminating the xrdp channel server (pid 501016) on display 14
[INFO ] X server on display 14 (pid 500982) returned exit code 1 and signal number 0
[INFO ] xrdp channel server for display 14 (pid 501016) exit code 0 and signal number 0
[INFO ] cleanup_sockets:
[INFO ] Process 500980 has exited
[INFO ] Calling auth_end for pid 500980 from pid 500968
[INFO ] ++ terminated session: UID 1000 (shayan), display :14.0, session_pid 500980, ip 192.168.1.128

[matt335672]

Doesn't look like the X server is starting. Look further up in the sesman.log for the messages generated when the X server is started.

[Saya47]

@matt335672 Hello! Thanks for replying.
Sorry about that, here's the full logs of today:

[INFO ] Socket 13: connection accepted from AF_UNIX
[INFO ] Received system login request from xrdp for user: shayan IP: 192.168.1.128
[INFO ] Terminal Server Users group is disabled, allowing authentication
[INFO ] Access permitted for user: shayan
[INFO ] Received request from xrdp to create a session for user shayan
[INFO ] ++ created session: username shayan, ip 192.168.1.128
[INFO ] Found X server running at /tmp/.X11-unix/X10
[INFO ] Found X server running at /tmp/.X11-unix/X11
[INFO ] Found X server running at /tmp/.X11-unix/X12
[INFO ] Found X server running at /tmp/.X11-unix/X13
[INFO ] Starting session: session_pid 634507, display :14.0, width 1920, height 1080, bpp 32, client ip 192.168.1.128, UID 1000
[INFO ] [session start] (display 14): calling auth_start_session from pid 634507
[INFO ] Starting X server on display 14: Xvnc :14 -auth .Xauthority -geometry 1920x1080 -depth 32 -rfbauth /home/shayan/.vnc/sesman_passwd-shayan@debian:14 -bs -nolisten tcp -localhost -dpi 96
[ERROR] Error calling exec (executable: Xvnc, arguments: Xvnc :14 -auth .Xauthority -geometry 1920x1080 -depth 32 -rfbauth /home/shayan/.vnc/sesman_passwd-shayan@debian:14 -bs -nolisten tcp -localhost -dpi 96) returned errno: 2, description: No such file or directory
[ERROR] Error starting X server on display 14
[ERROR] A fatal error has occurred attempting to start the X server on display 14, aborting connection
[WARN ] Timed out waiting for X server on display 14 to startup
[INFO ] Session started successfully for user shayan on display 14
[INFO ] Starting the xrdp channel server for display 14
[INFO ] Session in progress on display 14, waiting until the window manager (pid 634508) exits to end the session
[WARN ] Timed out waiting for X server on display 14 to startup
[ERROR] There is no X server active on display 14
[ERROR] A fatal error has occurred attempting to start the window manager on display 14, aborting connection
[WARN ] Window manager (pid 634508, display 14) exited quickly (0 secs). This could indicate a window manager config problem
[INFO ] Calling auth_stop_session from pid 634507
[INFO ] Terminating X server (pid 634509) on display 14
[INFO ] Terminating the xrdp channel server (pid 634570) on display 14
[INFO ] X server on display 14 (pid 634509) returned exit code 1 and signal number 0
[INFO ] xrdp channel server for display 14 (pid 634570) exit code 0 and signal number 0
[INFO ] cleanup_sockets:
[INFO ] Process 634507 has exited
[INFO ] Calling auth_end for pid 634507 from pid 500968
[INFO ] ++ terminated session: UID 1000 (shayan), display :14.0, session_pid 634507, ip 192.168.1.128

[matt335672]

Looks like you don't have Xvnc installed.

You don't say what you platform is. On Debian/Ubuntu/Kali etc, etc use sudo apt install tigervnc-standalone-server. For other platforms, you'll need to do something different.

[Saya47]

@matt335672 Are you sure? I'm on Debian Bullseye (Debian 11.6.0) and:
Linux debian 5.10.0-20-amd64 #1 SMP Debian 5.10.158-2 (2022-12-13) x86_64 GNU/Linux
Uhm, the XRDP works fine when my user is not logged in locally. I just want to be able to connect remotely while the same user is logged in locally, so I don't have to log out the user each time I want to connect via XRDP.
Thank you!

[Saya47]

I installed tigervnc-standalone-server but now it just goes back to this error:

[Saya47]

And the logs now say this:
sesman:

[INFO ] Socket 13: connection accepted from AF_UNIX
[INFO ] Received system login request from xrdp for user: shayan IP: 192.168.1.128
[INFO ] Terminal Server Users group is disabled, allowing authentication
[INFO ] Access permitted for user: shayan
[INFO ] Received request from xrdp to create a session for user shayan
[INFO ] ++ reconnected session: username shayan, display :14.0, session_pid 643797, ip 192.168.1.128
[INFO ] Starting session reconnection script on display 14: /etc/xrdp/reconnectwm.sh
[INFO ] Process 655698 has exited

xrdp:

[INFO ] Socket 12: connection accepted from 192.168.1.128:10405
[INFO ] Using default X.509 certificate: /etc/xrdp/cert.pem
[INFO ] Using default X.509 key file: /etc/xrdp/key.pem
[INFO ] Security protocol: configured [SSL|RDP], requested [SSL|HYBRID|HYBRID_EX|RDP], selected [SSL]
[ERROR] SSL_read: I/O error
[ERROR] libxrdp_force_read: header read error
[ERROR] Processing [ITU-T T.125] Connect-Initial failed
[ERROR] [MCS Connection Sequence] receive connection request failed
[ERROR] xrdp_sec_incoming: xrdp_mcs_incoming failed
[ERROR] xrdp_rdp_incoming: xrdp_sec_incoming failed
[ERROR] xrdp_process_main_loop: libxrdp_process_incoming failed
[ERROR] xrdp_iso_send: trans_write_copy_s failed
[ERROR] Sending [ITU T.125] DisconnectProviderUltimatum failed
[INFO ] Socket 12: connection accepted from 192.168.1.128:10406
[INFO ] Using default X.509 certificate: /etc/xrdp/cert.pem
[INFO ] Using default X.509 key file: /etc/xrdp/key.pem
[INFO ] Security protocol: configured [SSL|RDP], requested [SSL|HYBRID|HYBRID_EX|RDP], selected [SSL]
[INFO ] Connected client computer name: DESKTOP-SCRPN
[WARN ] Received [MS-RDPBCGR] TS_UD_HEADER type 0xc006 is unknown (ignored)
[WARN ] Received [MS-RDPBCGR] TS_UD_HEADER type 0xc00a is unknown (ignored)
[INFO ] xrdp_load_keyboard_layout: Keyboard information sent by the RDP client, keyboard_type:[0x07], keyboard_subtype:[0x00], keylayout:[0x00000409]
[INFO ] xrdp_load_keyboard_layout: model [] variant [] layout [us] options []
[INFO ] TLS connection established from 192.168.1.128:10406 TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384
[INFO ] xrdp_caps_process_pointer: client supports new(color) cursor
[INFO ] xrdp_process_offscreen_bmpcache: support level 1 cache size 10485760 MB cache entries 100
[INFO ] xrdp_caps_process_codecs: NSCodec(CA8D1BB9-000F-154F-589F-AE2D1A87E2D6), codec id [1], properties len [3]
[WARN ] xrdp_caps_process_codecs: unknown(2744CCD4-9D8A-4E74-803C-0ECBEEA19C54), codec id [5], properties len [49]
[INFO ] xrdp_caps_process_codecs: RemoteFX(76772F12-BD72-4463-AFB3-B73C9C6F7886), codec id [3], properties len [49]
[INFO ] Loading keymap file /etc/xrdp/km-00000409.ini
[WARN ] local keymap file for 0x00000409 found and doesn't match built in keymap, using local keymap file
[INFO ] Login screen monitor height is 1080 pixels over 194 mm (141 DPI)
[WARN ] Ignoring obsolete SCP port value '3350'
[INFO ] xrdp_wm_log_msg: sesman connect ok
[INFO ] xrdp_wm_log_msg: Performing login request for shayan
[INFO ] xrdp_wm_log_msg: login was successful - creating session
[INFO ] xrdp_wm_log_msg: session is available on display 14 for user shayan
[INFO ] xrdp_wm_log_msg: Connecting to session
[INFO ] loaded module 'libvnc.so' ok, interface size 4064, version 4
[INFO ] VNC: Clipboard (if available) is provided by chansrv facility
[INFO ] xrdp_wm_log_msg: Connecting to chansrv
[INFO ] Layout from OldLayout (geom=1920x1080 #screens=1) : 1804289383:(1920x1080+0+0)
[ERROR] xrdp_sec_recv: xrdp_mcs_recv failed
[ERROR] xrdp_rdp_recv: xrdp_sec_recv failed
[ERROR] libxrdp_process_data: xrdp_rdp_recv failed
[ERROR] xrdp_process_data_in: xrdp_process_loop failed
[ERROR] SSL_write: I/O error
[ERROR] xrdp_iso_send: trans_write_copy_s failed
[ERROR] Sending [ITU T.125] DisconnectProviderUltimatum failed

[matt335672]

@Saya47 - that isn't supported on systemd-based systems - see the FAQ. If you absolutely need that functionality, you'll need to move to Devuan.

The limitation is imposed by systemd. There's some discussion around possible workarounds in #2491 but nothing concrete yet.

[matt335672]

I've just updated the FAQ to reference #2491.

[Saya47]

Thanks very much @matt335672
So basically RDP on Windows enforces single session per user as well, I was hoping to get better treatment on Linux! But systemd comes to fail us once again! oh well.