Firejail is a SUID sandbox program that reduces the risk of security breaches by restricting the running environment of untrusted applications using Linux namespaces, seccomp-bpf and Linux capabilities. It allows a process and all its descendants to have their own private view of the globally shared kernel resources, such as the network stack, process table, mount table. Firejail can work in a SELinux or AppArmor environment, and it is integrated with Linux Control Groups.
Written in C with virtually no dependencies, the software runs on any Linux computer with a 3.x kernel version or newer. It can sandbox any type of processes: servers, graphical applications, and even user login sessions. The software includes sandbox profiles for a number of more common Linux programs, such as Mozilla Firefox, Chromium, VLC, Transmission etc.
The sandbox is lightweight, the overhead is low. There are no complicated configuration files to edit, no socket connections open, no daemons running in the background. All security features are implemented directly in Linux kernel and available on any Linux computer. To start the sandbox, prefix your command with “firejail”:
$ firejail firefox # starting Mozilla Firefox
$ firejail transmission-gtk # starting Transmission BitTorrent
$ firejail vlc # starting VideoLAN Client
$ sudo firejail /etc/init.d/nginx start
Project webpage: https://firejail.wordpress.com/
Download and Installation: https://firejail.wordpress.com/download-2/
Features: https://firejail.wordpress.com/features-3/
Documentation: https://firejail.wordpress.com/documentation-2/
FAQ: https://firejail.wordpress.com/support/frequently-asked-questions/
Version 0.9.41~rc1 was released.
A number of problems are being worked on. This is the output of "make test":
[...]
cd test/sysutils; ./sysutils.sh | grep TESTING
TESTING: cpio
netblue@debian:~/work/github/firejail/test/sysutils$ TESTING ERROR 1
TESTING: gzip
netblue@debian:~/work/github/firejail/test/sysutils$ TESTING ERROR 1
TESTING: xzdec
netblue@debian:~/work/github/firejail/test/sysutils$ TESTING ERROR 1
TESTING: xz
netblue@debian:~/work/github/firejail/test/sysutils$ TESTING ERROR 1
TESTING: less
TESTING: file
TESTING: tar
netblue@debian:~/work/github/firejail/test/sysutils$ TESTING ERROR 3.1
[...]
--user option was deprecated, please use "sudo -u username firejail application" instead.
Symlinks outside user home directories are allowed:
--whitelist=dirname_or_filename
Whitelist directory or file. This feature is implemented only
for user home, /dev, /media, /opt, /var, and /tmp directories.
With the exception of user home, both the link and the real file
should be in the same top directory. For /home, both the link
and the real file should be owned by the user.
Example:
$ firejail --noprofile --whitelist=~/.mozilla
$ firejail --whitelist=/tmp/.X11-unix --whitelist=/dev/null
$ firejail "--whitelist=/home/username/My Virtual Machines"
So far I've seen this working on Debian Jessie and Ubuntu 16.04, where I can get Firefox and Chromium running. There is more testing to come.
APPARMOR
AppArmor support is disabled by default at compile time. Use --enable-
apparmor configuration option to enable it:
$ ./configure --prefix=/usr --enable-apparmor
During software install, a generic AppArmor profile file, firejail-
default, is placed in /etc/apparmor.d directory. The profile needs to
be loaded into the kernel by running the following command as root:
# aa-enforce firejail-default
The installed profile tries to replicate some advanced security fea‐
tures inspired by kernel-based Grsecurity:
- Prevent information leakage in /proc and /sys directories. The
resulting file system is barely enough for running commands such
as "top" and "ps aux".
- Allow running programs only from well-known system paths, such
as /bin, /sbin, /usr/bin etc. Running programs and scripts from
user home or other directories writable by the user is not
allowed.
- Disable D-Bus. D-Bus has long been a huge security hole, and
most programs don't use it anyway. You should have no problems
running Chromium or Firefox.
To enable AppArmor confinement on top of your current Firejail security
features, pass --apparmor flag to Firejail command line. You can also
include apparmor command in a Firejail profile file. Example:
$ firejail --apparmor firefox
AppImage (http://appimage.org/) is a distribution-agnostic packaging format. The package is a regular ISO file containing all binaries, libraries and resources necessary for the program to run.
We introduce in this release support for sandboxing AppImage applications. Example:
$ firejail --appimage krita-3.0-x86_64.appimage
All Firejail sandboxing options should be available. A private home directory:
$ firejail --appimage --private krita-3.0-x86_64.appimage
or some basic X11 sandboxing:
$ firejail --appimage --net=none --x11 krita-3.0-x86_64.appimage
Major software applications distributing AppImage packages:
- Krita: https://krita.org/download/krita-desktop/
- OpenShot: http://www.openshot.org/download/
- Scribus: https://www.scribus.net/downloads/unstable-branch/
- MuseScore: https://musescore.org/en/download
More packages build by AppImage developer Simon Peter: https://bintray.com/probono/AppImages
AppImage project home: https://github.com/probonopd/AppImageKit
AUDIT
Audit feature allows the user to point out gaps in security profiles.
The implementation replaces the program to be sandboxed with a test
program. By default, we use faudit program distributed with Firejail. A
custom test program can also be supplied by the user. Examples:
Running the default audit program:
$ firejail --audit transmission-gtk
Running a custom audit program:
$ firejail --audit=~/sandbox-test transmission-gtk
In the examples above, the sandbox configures transmission-gtk profile
and starts the test program. The real program, transmission-gtk, will
not be started.
Limitations: audit feature is not implemented for --x11 commands.
--noexec=dirname_or_filename
Remount directory or file noexec, nodev and nosuid.
Example:
$ firejail --noexec=/tmp
/etc and /var are noexec by default. If there are more than one
mount operation on the path of the file or directory, noexec
should be applied to the last one. Always check if the change
took effect inside the sandbox.
--rmenv=name
Remove environment variable in the new sandbox.
Example:
$ firejail --rmenv=DBUS_SESSION_BUS_ADDRESS
BitTorrent: deluge, qbittorrent, rtorrent, transmission-gtk, transmission-qt, uget-gtk
File transfer: filezilla
Media: vlc, mpv, gnome-mplayer, audacity, rhythmbox, spotify, xplayer, xviewer, eom
Office: evince, gthumb, fbreader, pix, atril, xreader,
Chat/messaging: qtox, gitter, pidgin
Games: warzone2100, gnome-chess
Weather/climate: aweather
Astronomy: gpredict, stellarium
Browsers: Palemoon
Gitter, gThumb, mpv, Franz messenger, LibreOffice, pix, audacity, xz, xzdec, gzip, cpio, less, Atom Beta, Atom, jitsi, eom, uudeview tar (gtar), unzip, unrar, file, skypeforlinux, gnome-chess, inox, Slack