xserver_selinux(8) - Linux man page

Name

xserver_selinux - Security Enhanced Linux Policy for the xserver processes

Description

Security-Enhanced Linux secures the xserver processes via flexible mandatory access control.

The xserver processes execute with the xserver_t SELinux type. You can check if you have these processes running by executing the ps command with the -Z qualifier.

For example:

ps -eZ | grep xserver_t

Entrypoints

The xserver_t SELinux type can be entered via the "mtrr_device_t,unlabeled_t,proc_type,sysctl_type,filesystem_type,xserver_exec_t,file_type" file types. The default entrypoint paths for the xserver_t domain are the following:"

/dev/cpu/mtrr, /usr/bin/Xair, /usr/bin/Xorg, /usr/bin/Xephyr, /usr/X11R6/bin/X, /usr/X11R6/bin/Xorg, /usr/X11R6/bin/Xipaq, /usr/X11R6/bin/XFree86, /usr/X11R6/bin/Xwrapper, /etc/init.d/xfree86-common, all files on the system

Process Types

SELinux defines process types (domains) for each process running on the system

You can see the context of a process using the -Z option to ps

Policy governs the access confined processes have to files. SELinux xserver policy is very flexible allowing users to setup their xserver processes in as secure a method as possible.

The following process types are defined for xserver:

xserver_t

Note: semanage permissive -a xserver_t

can be used to make the process type xserver_t permissive. Permissive process types are not denied access by SELinux. AVC messages will still be generated.

Booleans

SELinux policy is customizable based on least access required. xserver policy is extremely flexible and has several booleans that allow you to manipulate the policy and run xserver with the tightest access possible.

If you want to support X userspace object manager, you must turn on the xserver_object_manager boolean.

setsebool -P xserver_object_manager 1

If you want to allow virtual machine to interact with the xserver, you must turn on the virt_use_xserver boolean.

setsebool -P virt_use_xserver 1

If you want to allows XServer to execute writable memory, you must turn on the allow_xserver_execmem boolean.

setsebool -P allow_xserver_execmem 1

If you want to support X userspace object manager, you must turn on the xserver_object_manager boolean.

setsebool -P xserver_object_manager 1

If you want to allow virtual machine to interact with the xserver, you must turn on the virt_use_xserver boolean.

setsebool -P virt_use_xserver 1

If you want to allows XServer to execute writable memory, you must turn on the allow_xserver_execmem boolean.

setsebool -P allow_xserver_execmem 1

File Contexts

SELinux requires files to have an extended attribute to define the file type.

You can see the context of a file using the -Z option to ls

Policy governs the access confined processes have to these files. SELinux xserver policy is very flexible allowing users to setup their xserver processes in as secure a method as possible.

The following file types are defined for xserver:

xserver_exec_t

- Set files with the xserver_exec_t type, if you want to transition an executable to the xserver_t domain.

xserver_log_t

- Set files with the xserver_log_t type, if you want to treat the data as xserver log data, usually stored under the /var/log directory.

xserver_tmpfs_t

- Set files with the xserver_tmpfs_t type, if you want to store xserver files on a tmpfs file system.

xserver_var_lib_t

- Set files with the xserver_var_lib_t type, if you want to store the xserver files under the /var/lib directory.

xserver_var_run_t

- Set files with the xserver_var_run_t type, if you want to store the xserver files under the /run directory.

Note: File context can be temporarily modified with the chcon command. If you want to permanently change the file context you need to use the semanage fcontext command. This will modify the SELinux labeling database. You will need to use restorecon to apply the labels.

Port Types

SELinux defines port types to represent TCP and UDP ports.

You can see the types associated with a port by using the following command:

semanage port -l

Policy governs the access confined processes have to these ports. SELinux xserver policy is very flexible allowing users to setup their xserver processes in as secure a method as possible.

The following port types are defined for xserver:

xserver_port_t
Default Defined Ports:: tcp 6000-6150

Managed Files

The SELinux process type xserver_t can manage files labeled with the following file types. The paths listed are the default paths for these file types. Note the processes UID still need to have DAC permissions.

file_type

all files on the system

Commands

semanage fcontext can also be used to manipulate default file context mappings.

semanage permissive can also be used to manipulate whether or not a process type is permissive.

semanage module can also be used to enable/disable/install/remove policy modules.

semanage port can also be used to manipulate the port definitions

semanage boolean can also be used to manipulate the booleans

system-config-selinux is a GUI tool available to customize SELinux policy settings.

Author

This manual page was auto-generated using sepolicy manpage by mgrepl.