Bug 2316431

Summary: ProFTPD Update Breaks ssh-agent SFTP Authentication
Product: [Fedora] Fedora EPEL Reporter: ICHIKAWA Tomohiro <ichikawa-t12>
Component: proftpdAssignee: Paul Howarth <paul>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
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Version: epel8CC: ingvar, paul
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OS: Linux   
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Description Flags
v1.3.6e-6
none
v1.3.6e-7 none

Description ICHIKAWA Tomohiro 2024-10-04 08:09:38 UTC 
Description of problem:
After updating ProFTPD, SFTP authentication through ssh-agent fails, while direct SFTP connection without ssh-agent works fine.

Version-Release number of selected component (if applicable):
Updated from proftpd v1.3.6e-6 to v1.3.6e-7

How reproducible:
Consistently reproducible after the update

Actual results:
SFTP authentication through ssh-agent fails after the update

Expected results:
SFTP authentication through ssh-agent should succeed, as it did before the update

Additional info:
- Public key authentication is being used
- Direct SFTP connection without ssh-agent works correctly
- The issue only occurs when using ssh-agent for authentication
Comment 1 Paul Howarth 2024-10-14 14:13:14 UTC 
Could you possibly try some debug tracing to compare the updated version with the previous version to see where things are different, and what exactly the error is?
http://www.proftpd.org/docs/howto/Tracing.html

I Took a look at the code and couldn't see any obvious interaction between the change in the update (which relates to processing configuration) and the ssh-agent functionality.
Comment 2 ICHIKAWA Tomohiro 2024-10-16 12:22:51 UTC 
Created attachment 2052282 [details]
v1.3.6e-6
Comment 3 ICHIKAWA Tomohiro 2024-10-16 12:23:18 UTC 
Created attachment 2052283 [details]
v1.3.6e-7
Comment 4 ICHIKAWA Tomohiro 2024-10-16 12:24:01 UTC 
ssh-agent may not be relevant.
I conducted a comparison test between v1.3.6e-6 and v1.3.6e-7 in a different environment.
Without using ssh-agent, I tried connecting directly with the sftp command. v1.3.6e-6 successfully connected, while v1.3.6e-7 failed.
I'm attaching the logs for each.
From a quick look at the logs, it appears that v1.3.6e-6 showed signs of opening the authorized_key file, but v1.3.6e-7 showed no signs of opening it at all.