Firejail

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.

Advanced Browser Security

How To Disable Network Access

Deep Dive

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://github.com/netblue30/firejail/wiki/Frequently-Asked-Questions

Wiki: https://github.com/netblue30/firejail/wiki

GitLab-CI status: https://gitlab.com/Firejail/firejail_ci/pipelines/

Video Channel: https://odysee.com/@netblue30:9?order=new

Backup Video Channel: https://www.bitchute.com/profile/JSBsA1aoQVfW/

Security vulnerabilities

We take security bugs very seriously. If you believe you have found one, please report it by emailing us at netblue30@protonmail.com

Installing

Debian

Debian stable (bullseye): We recommend to use the backports package.

Ubuntu

For Ubuntu 18.04+ and derivatives (such as Linux Mint), users are strongly advised to use the PPA.

How to add and install from the PPA:

sudo add-apt-repository ppa:deki/firejail
sudo apt-get update
sudo apt-get install firejail firejail-profiles

Reason: The firejail package for Ubuntu 20.04 has been left vulnerable to CVE-2021-26910 for months after a patch for it was posted on Launchpad:

• firejail version in Ubuntu 20.04 LTS is vulnerable to CVE-2021-26910

See also https://wiki.ubuntu.com/SecurityTeam/FAQ:

What software is supported by the Ubuntu Security team?

Ubuntu is currently divided into four components: main, restricted, universe and multiverse. All binary packages in main and restricted are supported by the Ubuntu Security team for the life of an Ubuntu release, while binary packages in universe and multiverse are supported by the Ubuntu community.

Additionally, the PPA version is likely to be more recent and to contain more profile fixes.

See the following discussions for details:

• Should I keep using the version of firejail available in my distro repos?
• How to install the latest version on Ubuntu and derivatives

Other

Firejail is included in a large number of Linux distributions.

You can also install one of the released packages, or clone Firejail’s source code from our Git repository and compile manually:

$ git clone https://github.com/netblue30/firejail.git
$ cd firejail
$ ./configure && make && sudo make install-strip

On Debian/Ubuntu you will need to install git and gcc compiler. AppArmor development libraries and pkg-config are required when using --apparmor ./configure option:

$ sudo apt-get install git build-essential libapparmor-dev pkg-config gawk

For --selinux option, add libselinux1-dev (libselinux-devel for Fedora).

Detailed information on using firejail from git is available on the wiki.

Running the sandbox

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

Run firejail --list in a terminal to list all active sandboxes. Example:

$ firejail --list
1617:netblue:/usr/bin/firejail /usr/bin/firefox-esr
7719:netblue:/usr/bin/firejail /usr/bin/transmission-qt
7779:netblue:/usr/bin/firejail /usr/bin/galculator
7874:netblue:/usr/bin/firejail /usr/bin/vlc --started-from-file file:///home/netblue/firejail-whitelist.mp4
7916:netblue:firejail --list

Desktop integration

Integrate your sandbox into your desktop by running the following two commands:

$ firecfg --fix-sound
$ sudo firecfg

The first command solves some shared memory/PID namespace bugs in PulseAudio software prior to version 9. The second command integrates Firejail into your desktop. You would need to logout and login back to apply PulseAudio changes.

Start your programs the way you are used to: desktop manager menus, file manager, desktop launchers. The integration applies to any program supported by default by Firejail. There are about 250 default applications in current Firejail version, and the number goes up with every new release. We keep the application list in /etc/firejail/firecfg.config file.

Security profiles

Most Firejail command line options can be passed to the sandbox using profile files. You can find the profiles for all supported applications in /etc/firejail directory.

If you keep additional Firejail security profiles in a public repository, please give us a link:

• https://github.com/chiraag-nataraj/firejail-profiles

• https://github.com/triceratops1/fe

Use this issue to request new profiles: #1139

You can also use this tool to get a list of syscalls needed by a program: contrib/syscalls.sh.

We also keep a list of profile fixes for previous released versions in etc-fixes directory.

Latest released version: 0.9.70

Current development version: 0.9.71

Milestone page: https://github.com/netblue30/firejail/milestone/1

Modified functionality

• modif: removed cgroups commands (#5190)
• modif: changed --disable-firetunnel into --enable-firetunnel in configure.ac (#5190)
• modif: disabled chroot by default in /etc/firejail/firejail.config (#5190)
• modif: shell none set as default (#5190)
• modif: removed --shell= (#5190)
• modif: private-lib disabled by default in /etc/firejail/firejail.config (#5190)

Restrict namespaces

       --restrict-namespaces
              Install a seccomp filter that  blocks  attempts  to  create  new
              cgroup, ipc, net, mount, pid, time, user or uts namespaces.

              Example:
              $ firejail --restrict-namespaces

       --restrict-namespaces=cgroup,ipc,net,mnt,pid,time,user,uts
              Install  a  seccomp filter that blocks attempts to create any of
              the specified namespaces. The filter examines the  arguments  of
              clone, unshare and setns system calls and returns error EPERM to
              the process (or kills it or logs the attempt, see  --seccomp-er‐
              ror-action below) if necessary. Note that the filter is not able
              to examine the arguments of clone3 system calls, and always  re‐
              sponds to these calls with error ENOSYS.

              Example:
              $ firejail --restrict-namespaces=user,net

Support for custom AppArmor profiles

      --apparmor
              Enable AppArmor confinement with the "firejail-default" AppArmor
              profile.   For more information, please see APPARMOR section be‐
              low.

       --apparmor=profile_name
              Enable AppArmor confinement  with  a  custom  AppArmor  profile.
              Note  that  profile  in question must already be loaded into the
              kernel.  For more information, please see APPARMOR  section  be‐

Landlock support - EXPERIMENTAL

For the next release (0.9.72), landlock support is experimental. It is disabled in the normal build or in the executable archives we provide. It will be "officially" released in 0.9.74, sometime early next year. For now, use --enable-landlock during software compile:

$ ./configure --enable-landlock

The functionality is segragated with ifdefs in the code, at times it might not even compile! Work in progress, the interface described in the man page below could change.

       --landlock
              Create a Landlock ruleset (if it doesn't already exist) and  add
              basic access rules to it. See LANDLOCK section for more informa‐
              tion.

       --landlock.proc=no|ro|rw
              Add an access rule for /proc directory (read-only if set  to  ro
              and read-write if set to rw). The access rule for /proc is added
              after this directory is set up in the sandbox. Access rules  for
              /proc  set  up  with other Landlock-related command-line options
              have no effect.

       --landlock.read=path
              Create a Landlock ruleset (if it doesn't already exist) and  add
              a read access rule for path.

       --landlock.write=path
              Create  a Landlock ruleset (if it doesn't already exist) and add
              a write access rule for path.

       --landlock.special=path
              Create a Landlock ruleset (if it doesn't already exist) and  add
              a  permission rule to create FIFO pipes, Unix domain sockets and
              block devices beneath given path.

       --landlock.execute=path
              Create a Landlock ruleset (if it doesn't already exist) and  add
              an execution permission rule for path.

              Example:
              $   firejail  --landlock.read=/  --landlock.write=/home  --land‐
              lock.execute=/usr

LANDLOCK
       Landlock is a Linux security module first introduced in the  5.13  ver‐
       sion  of  Linux  kernel.  It  allows unprivileged processes to restrict
       their access to the filesystem. Once imposed,  these  restrictions  can
       never  be  removed,  and  all child processes created by a Landlock-re‐
       stricted processes inherit these restrictions. Firejail supports  Land‐
       lock as an additional sandboxing feature. It can be used to ensure that
       a sandboxed application can only access files and directories  that  it
       was  explicitly  allowed  to  access.  Firejail supports populating the
       ruleset with both basic set of rules and with custom set of rules.  Ba‐
       sic  set  of  rules  allows read-only access to /bin, /dev, /etc, /lib,
       /opt, /proc, /usr and /var, read-write access to  the  home  directory,
       and allows execution of binaries located in /bin, /opt and /usr.

       Important notes:

              - A process can install a Landlock ruleset only if it has either
              CAP_SYS_ADMIN in its effective capability set, or  the  "No  New
              Privileges"  restriction  enabled. Because of this, enabling the
              Landlock feature will also cause Firejail to enable the "No  New
              Privileges"  restriction,  regardless  of  the  profile  or  the
              --no-new-privs command line option.

              - Access to the /proc directory is managed through  the  --land‐
              lock.proc command line option.

              -  Access  to  the  /etc  directory is automatically allowed. To
              override this, use the --writable-etc command line  option.  You
              can  also use the --private-etc option to restrict access to the
              /etc directory.

       To enable Landlock self-restriction on top of your current Firejail se‐
       curity features, pass --landlock flag to Firejail command line. You can
       also  use  --landlock.read,  --landlock.write,  --landlock.special  and
       --landlock.execute  options  together with --landlock or instead of it.
       Example:

              $ firejail --landlock --landlock.read=/media  --landlock.proc=ro
              mc

Profile Statistics

A small tool to print profile statistics. Compile and install as usual. The tool is installed in /usr/lib/firejail directory. Run it over the profiles in /etc/profiles:

$ /usr/lib/firejail/profstats /etc/firejail/*.profile
No include .local found in /etc/firejail/noprofile.profile
Warning: multiple caps in /etc/firejail/transmission-daemon.profile

Stats:
    profiles			1196
    include local profile	1195   (include profile-name.local)
    include globals		1169   (include globals.local)
    blacklist ~/.ssh		1067   (include disable-common.inc)
    seccomp			1087
    capabilities		1190
    noexec			1075   (include disable-exec.inc)
    noroot			995
    memory-deny-write-execute	269
    apparmor			713
    private-bin			695
    private-dev			1045
    private-etc			542
    private-lib			70
    private-tmp			918
    whitelist home directory	575
    whitelist var		858   (include whitelist-var-common.inc)
    whitelist run/user		1164   (include whitelist-runuser-common.inc
					or blacklist ${RUNUSER})
    whitelist usr/share		630   (include whitelist-usr-share-common.inc
    net none			404
    dbus-user none 		677
    dbus-user filter 		123
    dbus-system none 		837
    dbus-system filter 		12

New profiles:

onionshare, onionshare-cli, opera-developer, songrec, gdu, makedeb, lbry-viewer, tuir,