Bug 496363

Summary:	RDP client sees a black screen when connecting to KRdp - NLA Error
Product:	[Plasma] KRdp	Reporter:	Mike Smith <mikesmith929+kde>
Component:	general	Assignee:	Unassigned bugs <unassigned-bugs-null>
Status:	REPORTED ---
Severity:	major	CC:	ahiemstra
Priority:	NOR
Version First Reported In:	6.2.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Mike Smith 2024-11-16 21:52:30 UTC

***
If you're not sure this is actually a bug, instead post about it at https://discuss.kde.org

If you're reporting a crash, attach a backtrace with debug symbols; see https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports

Please remove this comment after reading and before submitting - thanks!
***

SUMMARY
When trying to connect to the Fedora KDE krdp server from a Windows 10 Pro remote desktop client, you can connect get the certificate, but all that appears is a black screen. 

STEPS TO REPRODUCE
1. Open Remote Desktop on the windows machine and connect to the Fedora KDE Krdp server
2. Attempt to log in with your credentials and accept the certificate.
3. 

OBSERVED RESULT
You'll see a black screen.

EXPECTED RESULT
Logging into the rdp server and seeing the remote desktop. 

SOFTWARE/OS VERSIONS
Windows: 10 Pro
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Fedora KDE
KDE Plasma Version: 6.2.3
KDE Frameworks Version:  6
Qt Version: 6.8.0

ADDITIONAL INFORMATION
Here's a partial log with on the krdp server:
  GNU nano 8.1                                                                                   krdperror.txt
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:211] [91621:170819] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_CONTINUE_NEEDED [0x00090312]
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:226] [91621:170819] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_COMPLETE_NEEDED [0x00090313]
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:238] [91621:170819] [ERROR][com.freerdp.core.transport] - BIO_read returned a system error 0: Success
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:238] [91621:170819] [ERROR][com.freerdp.core] - transport_read_layer:freerdp_set_last_error_ex ERRCONNECT_CONNECT_TRANSPORT_FAILED [0x0002000D]
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:238] [91621:170819] [ERROR][com.freerdp.core.nla] - [nla_recv] error: -1
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:238] [91621:170819] [ERROR][com.freerdp.core.transport] - client authentication failure
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:238] [91621:170819] [ERROR][com.freerdp.core.peer] - peer_recv_callback: CONNECTION_STATE_INITIAL - rdp_server_accept_nego() fail
Nov 16 14:00:07 cyan krdpserver[91621]: [14:00:07:238] [91621:170819] [ERROR][com.freerdp.core.transport] - transport_check_fds: transport->ReceiveCallback() - -1
Nov 16 14:00:09 cyan krdpserver[91621]: [14:00:09:974] [91621:170845] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_CONTINUE_NEEDED [0x00090312]
Nov 16 14:00:09 cyan krdpserver[91621]: [14:00:09:987] [91621:170845] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_COMPLETE_NEEDED [0x00090313]
Nov 16 14:00:09 cyan krdpserver[91621]: org.kde.krdp: New client connected:  Windows platform Windows NT
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: VA-API version 1.22.0
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Trying to open /usr/lib64/dri-nonfree/radeonsi_drv_video.so
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Trying to open /usr/lib64/dri-freeworld/radeonsi_drv_video.so
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Found init function __vaDriverInit_1_22
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: va_openDriver() returns 0
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: VA-API version 1.22.0
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Trying to open /usr/lib64/dri-nonfree/radeonsi_drv_video.so
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Trying to open /usr/lib64/dri-freeworld/radeonsi_drv_video.so
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Found init function __vaDriverInit_1_22
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: va_openDriver() returns 0
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: VA-API version 1.22.0
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Trying to open /usr/lib64/dri-nonfree/radeonsi_drv_video.so
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Trying to open /usr/lib64/dri-freeworld/radeonsi_drv_video.so
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: Found init function __vaDriverInit_1_22
Nov 16 14:00:09 cyan krdpserver[91621]: libva info: va_openDriver() returns 0

The error logs show a problem with Network Level Authentication (NLA). It seems like the connection might be trying to authenticate using NLA, and that is where it is failing? Not sure. Any way to disable this remotely if I have access via ssh to the Fedora server?

Also some libva information but that might just be a red herring.