22.4. Configuration Examples 22.4.1. Rsync as a daemon When using Red Hat Enterprise Linux, rsync can be used as a daemon so that multiple clients can directly communicate with it as a central server, in order to house centralized files and keep them synchronized. The following example will demonstrate running rsync as a daemon over a network socket in the correct domain, and how SELinux expects this daemon to be running on a pre-defined (in SELinux policy) TCP port. This example will then show how to modify SELinux policy to allow the rsync daemon to run normally on a non-standard port. This example will be performed on a single system to demonstrate SELinux policy and its control over local daemons and processes. Note that this is an example only and demonstrates how SELinux can affect rsync. Comprehensive documentation of rsync is beyond the scope of this document. See the official rsync documentation for further details. This example assumes that the rsync , setroubleshoot-server and audit packages are installed, that the SELinux targeted policy is used and that SELinux is running in enforcing mode. Procedure 22.1. Getting rsync to launch as rsync_t Run the getenforce command to confirm SELinux is running in enforcing mode: The command returns Enforcing when SELinux is running in enforcing mode. Run the which command to confirm that the rsync binary is in the system path: When running rsync as a daemon, a configuration file should be used and saved as /etc/rsyncd.conf . Note that the following configuration file used in this example is very simple and is not indicative of all the possible options that are available, rather it is just enough to demonstrate the rsync daemon: Now that a simple configuration file exists for rsync to operate in daemon mode, you can start it by running the following command: Ensure that rsyncd was successfully started (the output is supposed to look similar to the one below, only the time stamp will differ): SELinux can now enforce its protection mechanisms over the rsync daemon as it is now running in the rsync_t domain: This example demonstrated how to get rsyncd running in the rsync_t domain. Rsync can also be run as a socket-activated service. In that case, the rsyncd is not executed until a client tries to connect to the service. To enable rsyncd to run as a socket-activated service, follow the steps above. To start rsyncd as a socket-activated service, enter the following command as root: The example shows how to get this daemon successfully running on a non-default port. TCP port 10000 is used in the example. Procedure 22.2. Running the rsync daemon on a non-default port Modify the /etc/rsyncd.conf file and add the port = 10000 line at the top of the file in the global configuration area (that is, before any file areas are defined). The new configuration file will look like: After launching the rsync daemon with this new setting, a denial message similar to the following is logged by SELinux: Use the semanage utility to add TCP port 10000 to the SELinux policy in rsync_port_t : Now that TCP port 10000 has been added to the SELinux policy for rsync_port_t , rsyncd will start and operate normally on this port: SELinux has had its policy modified and is now permitting rsyncd to operate on TCP port 10000.

Commands:
~]USD getenforce Enforcing
~]USD which rsync /usr/bin/rsync
log file = /var/log/rsync.log pid file = /var/run/rsyncd.pid lock file = /var/run/rsync.lock [files] path = /srv/rsync comment = file area read only = false timeout = 300
~]# systemctl start rsyncd.service
~]# systemctl status rsyncd.service rsyncd.service - fast remote file copy program daemon Loaded: loaded (/usr/lib/systemd/system/rsyncd.service; disabled) Active: active (running) since Thu 2014-02-27 09:46:24 CET; 2s ago Main PID: 3220 (rsync) CGroup: /system.slice/rsyncd.service └─3220 /usr/bin/rsync --daemon --no-detach
~]USD ps -eZ | grep rsync system_u:system_r: rsync_t :s0 3220 ? 00:00:00 rsync
~]# systemctl start rsyncd.socket
log file = /var/log/rsyncd.log pid file = /var/run/rsyncd.pid lock file = /var/run/rsync.lock port = 10000 [files] path = /srv/rsync comment = file area read only = false timeout = 300
Jul 22 10:46:59 localhost setroubleshoot: SELinux is preventing the rsync (rsync_t) from binding to port 10000. For complete SELinux messages, run sealert -l c371ab34-639e-45ae-9e42-18855b5c2de8
~]# semanage port -a -t rsync_port_t -p tcp 10000
~]# systemctl start rsyncd.service
~]# netstat -lnp | grep 10000 tcp 0 0 0.0.0.0: 10000 0.0.0.0:* LISTEN 9910/rsync