Bug 1401510

Summary:	XDMCP MaxSessions configuration doesn't work as expected
Product:	Red Hat Enterprise Linux 6	Reporter:	Jos Collin <jcollin>
Component:	gdm	Assignee:	Ray Strode [halfline] <rstrode>
Status:	CLOSED WONTFIX	QA Contact:	Desktop QE <desktop-qa-list>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	6.8	CC:	cww, jcollin, qguo, siwu, yzheng
Target Milestone:	rc
Target Release:	6.10
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:
Clones:	1465356 (view as bug list)		Environment:
Last Closed:	2017-06-13 18:00:29 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:
Bug Blocks:	1461138, 1465356

Description Jos Collin 2016-12-05 13:23:19 UTC

Description of problem:
XDMCP MaxSessions configuration in /etc/gdm/custom.conf doesn't work as expected in all RHEL6 versions, which has gdm 2.30.4. The clients are able to start more sessions than the value specified in MaxSessions. There is no declining of additional sessions when the client initiates it. All the sessions will be active for a few minutes and will start declining one by one automatically. Finally, the count of the resulting active session(s) comes below the MaxSessions value.

Version-Release number of selected component (if applicable):
gdm 2.30.4

How reproducible:
Always

Steps to Reproduce:
1. Create an XDMCP server (VM) with the following configuration in /etc/gdm/custom.conf

 # GDM configuration storage

 [daemon]

 [security]
 DisallowTCP=false

 [xdmcp]
 Enable=true
 MaxSessions=2

 [greeter]

 [chooser]

 [debug]
 Enable=true

2. Initiate XDMCP sessions from 3 different client VMs using 
# Xephyr -query <serverip> :1

3. Monitor the sessions for 5 to 10 minutes.

Actual results:
It is possible to initiate more number of XDMCP sessions than the value of MaxSessions. The declining happens only after 5 to 10 minutes of waiting. Finally the resulting active sessions comes below the MaxSessions value.

Expected results:
The Xephyr command should decline the session immediately upon execution, when the count exceeds the MaxSessions value.

Additional info:

Comment 1 Jos Collin 2016-12-06 09:14:43 UTC

It is possible to start more XDMCP Sessions than the MaxSessions value using RHEL 7.x as the XDMCP server with gdm 3.8.4. But the additional sessions declines over time until the number of active sessions are equal to the MaxSessions value.

Comment 10 Chris Williams 2017-06-13 18:00:29 UTC

Red Hat Enterprise Linux 6 transitioned to the Production 3 Phase on May 10, 2017.  During the Production 3 Phase, Critical impact Security Advisories (RHSAs) and selected Urgent Priority Bug Fix Advisories (RHBAs) may be released as they become available.
 
The official life cycle policy can be reviewed here:
 
http://redhat.com/rhel/lifecycle
 
This issue does not appear to meet the inclusion criteria for the Production Phase 3 and will be marked as CLOSED/WONTFIX. If this remains a critical requirement, please contact Red Hat Customer Support to request a re-evaluation of the issue, citing a clear business justification.  Red Hat Customer Support can be contacted via the Red Hat Customer Portal at the following URL:
 
https://access.redhat.com

Comment 11 Ray Strode [halfline] 2017-12-06 20:56:58 UTC

*** Bug 1465356 has been marked as a duplicate of this bug. ***