Bug 503232 - Can't connect to credential-less RDP
Summary: Can't connect to credential-less RDP
Status: RESOLVED WORKSFORME
Alias: None
Product: krdc
Classification: Applications
Component: RDP (other bugs)
Version First Reported In: 25.04.0
Platform: Flatpak Linux
: NOR normal
Target Milestone: ---
Assignee: Urs Wolfer
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-04-23 13:58 UTC by exs5p8og
Modified: 2025-07-17 03:47 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Logs for krdc 25 requiring authentication (16.78 KB, text/plain)
2025-05-08 18:14 UTC, exs5p8og
Details
Logs for krdc 24 connecting without authentication (9.50 KB, text/plain)
2025-05-08 18:15 UTC, exs5p8og
Details

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Description exs5p8og 2025-04-23 13:58:55 UTC
SUMMARY  
KRDC `25.04.0` now always asks for credentials.  

STEPS TO REPRODUCE
1. Open an RDP connection (new connection or from bookmarks)  
2. See window for RDP connection.  
3. See credentials form.  
4. Click "OK" with the fields in blank.  
5. Form will appear again, click "OK" again.  
6. See "Could not connect to the server."  

OBSERVED RESULT
"Could not connect to the server." message

EXPECTED RESULT
Connection to remote desktop.  

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 42
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.13.0
Qt Version: 6.9.0

ADDITIONAL INFORMATION
Works properly with `24.12.3`. Reverted with `sudo flatpak update --commit=43837e1c6058e6ec8dec54fdc837c10ca62700ec79031160a8443b80957196b1 org.kde.krdc`
Comment 1 Fabio 2025-04-23 20:12:00 UTC
Hum, that's something that i use everyday.
Just press "OK" and you should get connected. If the window pops up again, then the remote host asked for authentication.
Disabling NLA/TLS auth from the connection could help, but it shouldn't be needed.
If not, please run from the commandline:
WLOG_LEVEL=DEBUG QT_LOGGING_RULES="KRDC=true" krdc
and paste some logs.
Comment 2 exs5p8og 2025-05-08 18:14:40 UTC
Created attachment 181080 [details]
Logs for krdc 25 requiring authentication
Comment 3 exs5p8og 2025-05-08 18:15:19 UTC
Created attachment 181081 [details]
Logs for krdc 24 connecting without authentication
Comment 4 exs5p8og 2025-05-08 18:23:21 UTC
I uploaded two logs, for KRDC 25 it requires authentication two times and fails to connect.  
For KRDC 24 it connects properly.  

To get the logs I had to run with `flatpak run org.kde.krdc` after updating the variables with flatseal.  
There's an error messages: `qt.core.logging: Ignoring malformed logging rule: '"KRDC=true"'`  

For more details, my setup is a VM running with VirtualBox with the remote display server enabled and authentication method set to null.
Comment 5 Fabio 2025-05-09 13:54:05 UTC
Thank you for the log files.
From what i can see under krdc 25 the problem is not related to credentials, but to the fact that the ssl library on your system are not validating the remote server certificate:
---
[14:06:15:282] [2:00000016] [DEBUG][com.freerdp.core.gcc] - [gcc_read_server_security_data]: Server rdp encryption method: 128BIT
[14:06:15:282] [2:00000016] [ERROR][com.freerdp.core] - [update_x509_from_info]: EVP_PKEY_fromdata_init(ctx) failed
[14:06:15:282] [2:00000016] [ERROR][com.freerdp.core] - [update_x509_from_info]: failed to update x509 from rdpCertInfo
---
This is probably caused by RDP using weak, old ciphers that are blocked by default on recent openssl versions.
The issue happened also on the FreeRDP flatpack:
https://github.com/FreeRDP/FreeRDP/issues/11104
https://github.com/flathub/com.freerdp.FreeRDP/pull/62
https://github.com/flathub/com.freerdp.FreeRDP/issues/63

Can you try to download this openssl config file:
https://github.com/flathub/com.freerdp.FreeRDP/pull/62/files#diff-fdfe97f9eaa77cd3e907822fbad45a5ec1e0d12ef455fd6bc588075c091c81bb
and run krdc defining "OPENSSL_CONF=/app/share/legacy-openssl.cnf" as in this file:
https://github.com/flathub/com.freerdp.FreeRDP/pull/62/files#diff-26581aa765cc6319e6f739ef4afd09201be927a8b5415a659f7104c37ae819df
It could work. if it does, i can try to get these changes pushed into our flatpak.
Comment 6 Fabio 2025-06-17 19:34:08 UTC
Were you able to confirm if the proposed solution fixes your problem?
Comment 7 Bug Janitor Service 2025-07-02 03:47:30 UTC
๐Ÿ›๐Ÿงน โš ๏ธ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!
Comment 8 Bug Janitor Service 2025-07-17 03:47:38 UTC
๐Ÿ›๐Ÿงน This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.