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Bug 1187975 - SELinux blocks LightDM VNC server
Summary: SELinux blocks LightDM VNC server
Alias: None
Product: Fedora
Classification: Fedora
Component: selinux-policy
Version: 21
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
Assignee: Miroslav Grepl
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2015-02-01 03:06 UTC by Ian Pilcher
Modified: 2015-02-15 03:29 UTC (History)
5 users (show)

Fixed In Version: selinux-policy-3.13.1-105.3.fc21
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-02-15 03:29:31 UTC
Type: Bug

Attachments (Terms of Use)

Description Ian Pilcher 2015-02-01 03:06:05 UTC
Description of problem:
LightDM has the capability of listening on VNC ports and launching Xvnc on demand.  SELinux is blocking LightDM (xdm_t) from listening on VNC ports (vnc_port_t):

type=AVC msg=audit(1422759252.925:895): avc:  denied  { name_bind } for  pid=25908 comm="lightdm" src=5910 scontext=system_u:system_r:xdm_t:s0-s0:c0.c1023 tcontext=system_u:object_r:vnc_port_t:s0 tclass=tcp_socket permissive=0

Boolean worthy?

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

How reproducible:

Steps to Reproduce:
1. Enable LightDM VNC server (enabled=true in [VNCServer] section of 
2. [Re]start LightDM

Actual results:
LightDM cannot bind to VNC port.  Log contains messages such as:

Jan 31 20:54:12 lightdm[25908]: ** (lightdm:25908): WARNING **: Failed to create IPv4 VNC socket: Error binding to address: Permission denied
Jan 31 20:54:12 lightdm[25908]: ** (lightdm:25908): WARNING **: Failed to create IPv6 VNC socket: Error binding to address: Permission denied

Expected results:
LightDM is able to listen on VNC port.

Additional info:
Workaround is to start Xvnc with a systemd socket and use XDMCP.

Comment 1 Daniel Walsh 2015-02-01 11:56:10 UTC
Yes this would seem to need a boolean.

Comment 2 Lukas Vrabec 2015-02-02 12:27:06 UTC
commit ddee7efa224213cd817fb3e9394a772b9964c656
Author: Lukas Vrabec <lvrabec>
Date:   Mon Feb 2 13:09:27 2015 +0100

    Added boolean xdm_bind_vnc_tcp_port. BZ(1187975)

Comment 3 Fedora Update System 2015-02-05 13:15:29 UTC
selinux-policy-3.13.1-105.3.fc21 has been submitted as an update for Fedora 21.

Comment 4 Fedora Update System 2015-02-06 04:04:04 UTC
Package selinux-policy-3.13.1-105.3.fc21:
* should fix your issue,
* was pushed to the Fedora 21 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing selinux-policy-3.13.1-105.3.fc21'
as soon as you are able to.
Please go to the following url:
then log in and leave karma (feedback).

Comment 5 Fedora Update System 2015-02-15 03:29:31 UTC
selinux-policy-3.13.1-105.3.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.

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