thumb_selinux - Man Page

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

The thumb processes execute with the thumb_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 thumb_t

The thumb_t SELinux type can be entered via the thumb_exec_t file type.

The default entrypoint paths for the thumb_t domain are the following:

/usr/bin/[^/]*thumbnailer, /usr/bin/gnome-[^/]*-thumbnailer(.sh)?, /usr/lib/tumbler-?[^/]*/tumblerd, /usr/bin/raw-thumbnailer, /usr/bin/ffmpegthumbnailer, /usr/bin/whaaw-thumbnailer, /usr/bin/evince-thumbnailer, /usr/bin/mate-thumbnail-font, /usr/bin/gnome-thumbnail-font, /usr/bin/gsf-office-thumbnailer, /usr/bin/totem-video-thumbnailer, /usr/bin/shotwell-video-thumbnailer

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 psbP

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

The following process types are defined for thumb:

thumb_t

Note: semanage permissive -a thumb_t can be used to make the process type thumb_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.

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

If you want to deny user domains applications to map a memory region as both executable and writable, this is dangerous and the executable should be reported in bugzilla, you must turn on the deny_execmem boolean. Disabled by default.

setsebool -P deny_execmem 1

If you want to allow system to run with NIS, you must turn on the nis_enabled boolean. Disabled by default.

setsebool -P nis_enabled 1

If you want to allow all unconfined executables to use libraries requiring text relocation that are not labeled textrel_shlib_t, you must turn on the selinuxuser_execmod boolean. Enabled by default.

setsebool -P selinuxuser_execmod 1

The SELinux process type thumb_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.

cifs_t

ecryptfs_t

/home/[^/]+/.Private(/.*)?
/home/[^/]+/.ecryptfs(/.*)?

fusefs_t

/run/user/[0-9]+/gvfs

nfs_t

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 lsbP

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

STANDARD FILE CONTEXT

SELinux defines the file context types for the thumb, if you wanted to store files with these types in a different paths, you need to execute the semanage command to specify alternate labeling and then use restorecon to put the labels on disk.

semanage fcontext -a -t thumb_exec_t '/srv/thumb/content(/.*)?'
restorecon -R -v /srv/mythumb_content

Note: SELinux often uses regular expressions to specify labels that match multiple files.

The following file types are defined for thumb:

thumb_exec_t

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

Paths:

/usr/bin/[^/]*thumbnailer, /usr/bin/gnome-[^/]*-thumbnailer(.sh)?, /usr/lib/tumbler-?[^/]*/tumblerd, /usr/bin/raw-thumbnailer, /usr/bin/ffmpegthumbnailer, /usr/bin/whaaw-thumbnailer, /usr/bin/evince-thumbnailer, /usr/bin/mate-thumbnail-font, /usr/bin/gnome-thumbnail-font, /usr/bin/gsf-office-thumbnailer, /usr/bin/totem-video-thumbnailer, /usr/bin/shotwell-video-thumbnailer

thumb_home_t

- Set files with the thumb_home_t type, if you want to store thumb files in the users home directory.

Paths:

/home/[^/]+/.thumbnails(/.*)?, /home/[^/]+/missfont.log.*, /home/[^/]+/.cache/thumbnails(/.*)?

thumb_tmp_t

- Set files with the thumb_tmp_t type, if you want to store thumb temporary files in the /tmp directories.

thumb_tmpfs_t

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

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.

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 boolean can also be used to manipulate the booleans

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

This manual page was auto-generated using sepolicy manpage .

selinux(8), thumb(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), setsebool(8)