Provided by: firejail_0.9.52-2_amd64 
NAME
Firejail - Linux namespaces sandbox program
SYNOPSIS
Start a sandbox:
firejail [OPTIONS] [program and arguments]
File transfer from an existing sandbox
firejail {--ls | --get | --put} dir_or_filename
Network traffic shaping for an existing sandbox:
firejail --bandwidth={name|pid} bandwidth-command
Monitoring:
firejail {--list | --netstats | --top | --tree}
Miscellaneous:
firejail {-? | --debug-caps | --debug-errnos | --debug-syscalls | --debug-protocols | --help |
--version}
DESCRIPTION
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.
Firejail allows the user to manage application security using security profiles. Each profile defines a
set of permissions for a specific application or group of applications. The software includes security
profiles for a number of more common Linux programs, such as Mozilla Firefox, Chromium, VLC, Transmission
etc.
USAGE
Without any options, the sandbox consists of a filesystem build in a new mount namespace, and new PID and
UTS namespaces. IPC, network and user namespaces can be added using the command line options. The default
Firejail filesystem is based on the host filesystem with the main system directories mounted read-only.
These directories are /etc, /var, /usr, /bin, /sbin, /lib, /lib32, /libx32 and /lib64. Only /home and
/tmp are writable.
As it starts up, Firejail tries to find a security profile based on the name of the application. If an
appropriate profile is not found, Firejail will use a default profile. The default profile is quite
restrictive. In case the application doesn't work, use --noprofile option to disable it. For more
information, please see SECURITY PROFILES section below.
If a program argument is not specified, Firejail starts /bin/bash shell. Examples:
$ firejail [OPTIONS] # starting a /bin/bash shell
$ firejail [OPTIONS] firefox # starting Mozilla Firefox
# sudo firejail [OPTIONS] /etc/init.d/nginx start
OPTIONS
-- Signal the end of options and disables further option processing.
--allow-debuggers
Allow tools such as strace and gdb inside the sandbox by whitelisting system calls ptrace and
process_vm_readv. This option is only available when running on Linux kernels 4.8 or newer - a
kernel bug in ptrace system call allows a full bypass of the seccomp filter.
Example:
$ firejail --allow-debuggers --profile=/etc/firejail/firefox.profile strace -f firefox
--allusers
All directories under /home are visible inside the sandbox. By default, only current user home
directory is visible.
Example:
$ firejail --allusers
--apparmor
Enable AppArmor confinement. For more information, please see APPARMOR section below.
--appimage
Sandbox an AppImage (https://appimage.org/) application.
Example:
$ firejail --appimage krita-3.0-x86_64.appimage
$ firejail --appimage --private krita-3.0-x86_64.appimage
$ firejail --appimage --net=none --x11 krita-3.0-x86_64.appimage
--audit
Audit the sandbox, see AUDIT section for more details.
--audit=test-program
Audit the sandbox, see AUDIT section for more details.
--bandwidth=name|pid
Set bandwidth limits for the sandbox identified by name or PID, see TRAFFIC SHAPING section for
more details.
--bind=filename1,filename2
Mount-bind filename1 on top of filename2. This option is only available when running as root.
Example:
# firejail --bind=/config/etc/passwd,/etc/passwd
--blacklist=dirname_or_filename
Blacklist directory or file. File globbing is supported, see FILE GLOBBING section for more
details.
Example:
$ firejail --blacklist=/sbin --blacklist=/usr/sbin
$ firejail --blacklist=~/.mozilla
$ firejail "--blacklist=/home/username/My Virtual Machines"
$ firejail --blacklist=/home/username/My\ Virtual\ Machines
--build
The command builds a whitelisted profile. The profile is printed on the screen. If /usr/bin/strace
is installed on the system, it also builds a whitelisted seccomp profile. The program is run in a
very relaxed sandbox, with only --caps.drop=all and --nonewprivs. Programs that raise user
privileges are not supported in order to allow strace to run. Chromium and Chromium-based browsers
will not work.
Example:
$ firejail --build=profile-file vlc ~/Videos/test.mp4
--build=profile-file
The command builds a whitelisted profile, and saves it in profile-file. If /usr/bin/strace is
installed on the system, it also builds a whitelisted seccomp profile. The program is run in a
very relaxed sandbox, with only --caps.drop=all and --nonewprivs. Programs that raise user
privileges are not supported in order to allow strace to run. Chromium and Chromium-based browsers
will not work.
Example:
$ firejail --build=vlc.profile vlc ~/Videos/test.mp4
-c Execute command and exit.
--caps Linux capabilities is a kernel feature designed to split up the root privilege into a set of
distinct privileges. These privileges can be enabled or disabled independently, thus restricting
what a process running as root can do in the system.
By default root programs run with all capabilities enabled. --caps option disables the following
capabilities: CAP_SYS_MODULE, CAP_SYS_RAWIO, CAP_SYS_BOOT, CAP_SYS_NICE, CAP_SYS_TTY_CONFIG,
CAP_SYSLOG, CAP_MKNOD, CAP_SYS_ADMIN. The filter is applied to all processes started in the
sandbox.
Example:
$ sudo firejail --caps /etc/init.d/nginx start
--caps.drop=all
Drop all capabilities for the processes running in the sandbox. This option is recommended for
running GUI programs or any other program that doesn't require root privileges. It is a must-have
option for sandboxing untrusted programs installed from unofficial sources - such as games, Java
programs, etc.
Example:
$ firejail --caps.drop=all warzone2100
--caps.drop=capability,capability,capability
Define a custom blacklist Linux capabilities filter.
Example:
$ firejail --caps.drop=net_broadcast,net_admin,net_raw
--caps.keep=capability,capability,capability
Define a custom whitelist Linux capabilities filter.
Example:
$ sudo firejail --caps.keep=chown,net_bind_service,setgid,\ setuid /etc/init.d/nginx start
--caps.print=name|pid
Print the caps filter for the sandbox identified by name or by PID.
Example:
$ firejail --name=mygame --caps.drop=all warzone2100 &
$ firejail --caps.print=mygame
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --caps.print=3272
--cgroup=tasks-file
Place the sandbox in the specified control group. tasks-file is the full path of cgroup tasks
file.
Example:
# firejail --cgroup=/sys/fs/cgroup/g1/tasks
--chroot=dirname
Chroot the sandbox into a root filesystem. Unlike the regular filesystem container, the system
directories are mounted read-write. If the sandbox is started as a regular user, default seccomp
and capabilities filters are enabled. This option is not available on Grsecurity systems.
Example:
$ firejail --chroot=/media/ubuntu warzone2100
--cpu=cpu-number,cpu-number,cpu-number
Set CPU affinity.
Example:
$ firejail --cpu=0,1 handbrake
--cpu.print=name|pid
Print the CPU cores in use by the sandbox identified by name or by PID.
Example:
$ firejail --name=mygame --caps.drop=all warzone2100 &
$ firejail --cpu.print=mygame
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --cpu.print=3272
--csh Use /bin/csh as default user shell.
Example:
$ firejail --csh
--debug
Print debug messages.
Example:
$ firejail --debug firefox
--debug-blacklists
Debug blacklisting.
Example:
$ firejail --debug-blacklists firefox
--debug-caps
Print all recognized capabilities in the current Firejail software build and exit.
Example:
$ firejail --debug-caps
--debug-check-filename
Debug filename checking.
Example:
$ firejail --debug-check-filename firefox
--debug-errnos
Print all recognized error numbers in the current Firejail software build and exit.
Example:
$ firejail --debug-errnos
--debug-private-lib
Debug messages for --private-lib option.
--debug-protocols
Print all recognized protocols in the current Firejail software build and exit.
Example:
$ firejail --debug-protocols
--debug-syscalls
Print all recognized system calls in the current Firejail software build and exit.
Example:
$ firejail --debug-syscalls
--debug-whitelists
Debug whitelisting.
Example:
$ firejail --debug-whitelists firefox
--defaultgw=address
Use this address as default gateway in the new network namespace.
Example:
$ firejail --net=eth0 --defaultgw=10.10.20.1 firefox
--disable-mnt
Disable /mnt, /media, /run/mount and /run/media access.
Example:
$ firejail --disable-mnt firefox
--dns=address
Set a DNS server for the sandbox. Up to three DNS servers can be defined. Use this option if you
don't trust the DNS setup on your network.
Example:
$ firejail --dns=8.8.8.8 --dns=8.8.4.4 firefox
Note: this feature is not supported on systemd-resolved setups.
--dns.print=name|pid
Print DNS configuration for a sandbox identified by name or by PID.
Example:
$ firejail --name=mygame --caps.drop=all warzone2100 &
$ firejail --dns.print=mygame
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --dns.print=3272
--env=name=value
Set environment variable in the new sandbox.
Example:
$ firejail --env=LD_LIBRARY_PATH=/opt/test/lib
--force
By default, if Firejail is started in an existing sandbox, it will run the program in a bash
shell. This option disables this behavior, and attempts to start Firejail in the existing
sandbox. There could be lots of reasons for it to fail, for example if the existing sandbox
disables admin capabilities, SUID binaries, or if it runs seccomp.
--fs.print=name|print
Print the filesystem log for the sandbox identified by name or by PID.
Example:
$ firejail --name=mygame --caps.drop=all warzone2100 &
$ firejail --fs.print=mygame
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --fs.print=3272
--get=name|pid filename
Get a file from sandbox container, see FILE TRANSFER section for more details.
--git-install
Download, compile and install mainline git version of Firejail from the official repository on
GitHub. The software is installed in /usr/local/bin, and takes precedence over the (old) version
installed in /usr/bin. If for any reason the new version doesn't work, the user can uninstall it
using --git-uninstall command and revert to the old version.
Prerequisites: git and compile support are required for this command to work. On Debian/Ubuntu
systems this support is installed using "sudo apt-get install build-essential git".
Example:
$ firejail --git-install
--git-uninstall
Remove the Firejail version previously installed in /usr/local/bin using --git-install command.
Example:
$ firejail --git-uninstall
-?, --help
Print options end exit.
--hostname=name
Set sandbox hostname.
Example:
$ firejail --hostname=officepc firefox
--hosts-file=file
Use file as /etc/hosts.
Example:
$ firejail --hosts-file=~/myhosts firefox
--ignore=command
Ignore command in profile file.
Example:
$ firejail --ignore=shell --ignore=seccomp firefox
--interface=interface
Move interface in a new network namespace. Up to four --interface options can be specified. Note:
wlan devices are not supported for this option.
Example:
$ firejail --interface=eth1 --interface=eth0.vlan100
--ip=address
Assign IP addresses to the last network interface defined by a --net option. A default gateway is
assigned by default.
Example:
$ firejail --net=eth0 --ip=10.10.20.56 firefox
--ip=none
No IP address and no default gateway are configured for the last interface defined by a --net
option. Use this option in case you intend to start an external DHCP client in the sandbox.
Example:
$ firejail --net=eth0 --ip=none
If the corresponding interface doesn't have an IP address configured, this option is enabled by
default.
--ip6=address
Assign IPv6 addresses to the last network interface defined by a --net option.
Example:
$ firejail --net=eth0 --ip6=2001:0db8:0:f101::1/64 firefox
Note: you don't need this option if you obtain your ip6 address from router via SLAAC (your ip6
address and default route will be configured by kernel automatically).
--iprange=address,address
Assign an IP address in the provided range to the last network interface defined by a --net
option. A default gateway is assigned by default.
Example:
$ firejail --net=eth0 --iprange=192.168.1.100,192.168.1.150
--ipc-namespace
Enable a new IPC namespace if the sandbox was started as a regular user. IPC namespace is enabled
by default for sandboxes started as root.
Example:
$ firejail --ipc-namespace firefox
--join=name|pid
Join the sandbox identified by name or by PID. By default a /bin/bash shell is started after
joining the sandbox. If a program is specified, the program is run in the sandbox. If --join
command is issued as a regular user, all security filters are configured for the new process the
same they are configured in the sandbox. If --join command is issued as root, the security
filters, cgroups and cpus configurations are not applied to the process joining the sandbox.
Example:
$ firejail --name=mygame --caps.drop=all warzone2100 &
$ firejail --join=mygame
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --join=3272
--join-filesystem=name|pid
Join the mount namespace of the sandbox identified by name or PID. By default a /bin/bash shell is
started after joining the sandbox. If a program is specified, the program is run in the sandbox.
This command is available only to root user. Security filters, cgroups and cpus configurations
are not applied to the process joining the sandbox.
--join-network=name|PID
Join the network namespace of the sandbox identified by name. By default a /bin/bash shell is
started after joining the sandbox. If a program is specified, the program is run in the sandbox.
This command is available only to root user. Security filters, cgroups and cpus configurations
are not applied to the process joining the sandbox. Example:
# start firefox
$ firejail --net=eth0 --name=browser firefox &
# change netfilter configuration
$ sudo firejail --join-network=browser bash -c "cat /etc/firejail/nolocal.net | /sbin/iptables-
restore"
# verify netfilter configuration
$ sudo firejail --join-network=browser /sbin/iptables -vL
# verify IP addresses
$ sudo firejail --join-network=browser ip addr
Switching to pid 1932, the first child process inside the sandbox
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0-1931: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether 76:58:14:42:78:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.158/24 brd 192.168.1.255 scope global eth0-1931
valid_lft forever preferred_lft forever
inet6 fe80::7458:14ff:fe42:78e4/64 scope link
valid_lft forever preferred_lft forever
--join-or-start=name
Join the sandbox identified by name or start a new one. Same as "firejail --join=name" if sandbox
with specified name exists, otherwise same as "firejail --name=name ..."
Note that in contrary to other join options there is respective profile option.
--ls=name|pid dir_or_filename
List files in sandbox container, see FILE TRANSFER section for more details.
--list List all sandboxes, see MONITORING section for more details.
Example:
$ firejail --list
7015:netblue:firejail firefox
7056:netblue:firejail --net=eth0 transmission-gtk
7064:netblue:firejail --noroot xterm
$
--mac=address
Assign MAC addresses to the last network interface defined by a --net option.
Example:
$ firejail --net=eth0 --mac=00:11:22:33:44:55 firefox
--machine-id
Spoof id number in /etc/machine-id file - a new random id is generated inside the sandbox.
Example:
$ firejail --machine-id
--memory-deny-write-execute
Install a seccomp filter to block attempts to create memory mappings that are both writable and
executable, to change mappings to be executable, or to create executable shared memory. The filter
examines the arguments of mmap, mmap2, mprotect, pkey_mprotect and shmat system calls and kills
the process if necessary.
Note: shmat is not implemented as a system call on some platforms including i386, and it cannot be
handled by seccomp-bpf.
--mtu=number
Assign a MTU value to the last network interface defined by a --net option.
Example:
$ firejail --net=eth0 --mtu=1492
--name=name
Set sandbox name. Several options, such as --join and --shutdown, can use this name to identify a
sandbox.
Example:
$ firejail --name=mybrowser firefox
--net=bridge_interface
Enable a new network namespace and connect it to this bridge interface. Unless specified with
option --ip and --defaultgw, an IP address and a default gateway will be assigned automatically to
the sandbox. The IP address is verified using ARP before assignment. The address configured as
default gateway is the bridge device IP address. Up to four --net bridge devices can be defined.
Mixing bridge and macvlan devices is allowed.
Example:
$ sudo brctl addbr br0
$ sudo ifconfig br0 10.10.20.1/24
$ sudo brctl addbr br1
$ sudo ifconfig br1 10.10.30.1/24
$ firejail --net=br0 --net=br1
--net=ethernet_interface
Enable a new network namespace and connect it to this ethernet interface using the standard Linux
macvlan driver. Unless specified with option --ip and --defaultgw, an IP address and a default
gateway will be assigned automatically to the sandbox. The IP address is verified using ARP before
assignment. The address configured as default gateway is the default gateway of the host. Up to
four --net devices can be defined. Mixing bridge and macvlan devices is allowed. Note: wlan
devices are not supported for this option.
Example:
$ firejail --net=eth0 --ip=192.168.1.80 --dns=8.8.8.8 firefox
--net=none
Enable a new, unconnected network namespace. The only interface available in the new namespace is
a new loopback interface (lo). Use this option to deny network access to programs that don't
really need network access.
Example:
$ firejail --net=none vlc
Note: --net=none can crash the application on some platforms. In these cases, it can be replaced
with --protocol=unix.
--netns=name
Run the program in a named, persistent network namespace. These can be created and configured
using "ip netns".
--netfilter
Enable a default firewall if a new network namespace is created inside the sandbox. This option
has no effect for sandboxes using the system network namespace.
The default firewall is optimized for regular desktop applications. No incoming connections are
accepted:
*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
# allow ping
-A INPUT -p icmp --icmp-type destination-unreachable -j ACCEPT
-A INPUT -p icmp --icmp-type time-exceeded -j ACCEPT
-A INPUT -p icmp --icmp-type echo-request -j ACCEPT
# drop STUN (WebRTC) requests
-A OUTPUT -p udp --dport 3478 -j DROP
-A OUTPUT -p udp --dport 3479 -j DROP
-A OUTPUT -p tcp --dport 3478 -j DROP
-A OUTPUT -p tcp --dport 3479 -j DROP
COMMIT
Example:
$ firejail --net=eth0 --netfilter firefox
--netfilter=filename
Enable the firewall specified by filename if a new network namespace is created inside the
sandbox. This option has no effect for sandboxes using the system network namespace.
Please use the regular iptables-save/iptables-restore format for the filter file. The following
examples are available in /etc/firejail directory:
webserver.net is a webserver firewall that allows access only to TCP ports 80 and 443. Example:
$ firejail --netfilter=/etc/firejail/webserver.net --net=eth0 \
/etc/init.d/apache2 start
nolocal.net is a desktop client firewall that disable access to local network. Example:
$ firejail --netfilter=/etc/firejail/nolocal.net \
--net=eth0 firefox
--netfilter=filename,arg1,arg2,arg3 ...
This is the template version of the previous command. $ARG1, $ARG2, $ARG3 ... in the firewall
script are replaced with arg1, arg2, arg3 ... passed on the command line. Up to 16 arguments are
supported. Example:
$ firejail --net=eth0 --ip=192.168.1.105 \
--netfilter=/etc/firejail/tcpserver.net,5001 server-program
--netfilter.print=name|pid
Print the firewall installed in the sandbox specified by name or PID. Example:
$ firejail --name=browser --net=eth0 --netfilter firefox &
$ firejail --netfilter.print=browser
--netfilter6=filename
Enable the IPv6 firewall specified by filename if a new network namespace is created inside the
sandbox. This option has no effect for sandboxes using the system network namespace. Please use
the regular iptables-save/iptables-restore format for the filter file.
--netfilter6.print=name|pid
Print the IPv6 firewall installed in the sandbox specified by name or PID. Example:
$ firejail --name=browser --net=eth0 --netfilter firefox &
$ firejail --netfilter6.print=browser
--netstats
Monitor network namespace statistics, see MONITORING section for more details.
Example:
$ firejail --netstats
PID User RX(KB/s) TX(KB/s) Command
1294 netblue 53.355 1.473 firejail --net=eth0 firefox
7383 netblue 9.045 0.112 firejail --net=eth0 transmission
--nice=value
Set nice value for all processes running inside the sandbox. Only root may specify a negative
value.
Example:
$ firejail --nice=2 firefox
--no3d Disable 3D hardware acceleration.
Example:
$ firejail --no3d firefox
--noblacklist=dirname_or_filename
Disable blacklist for this directory or file.
Example:
$ firejail
$ nc dict.org 2628
bash: /bin/nc: Permission denied
$ exit
$ firejail --noblacklist=/bin/nc
$ nc dict.org 2628
220 pan.alephnull.com dictd 1.12.1/rf on Linux 3.14-1-amd64
--nodvd
Disable DVD and audio CD devices.
Example:
$ firejail --nodvd
--noexec=dirname_or_filename
Remount directory or file noexec, nodev and nosuid. File globbing is supported, see FILE GLOBBING
section for more details.
Example:
$ firejail --noexec=/tmp
/etc and /var are noexec by default if the sandbox was started as a regular user. 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.
--nogroups
Disable supplementary groups. Without this option, supplementary groups are enabled for the user
starting the sandbox. For root user supplementary groups are always disabled.
Note: By default all regular user groups are removed with the exception of the current user. This
can be changed using --allusers command option.
Example:
$ id
uid=1000(netblue) gid=1000(netblue) groups=1000(netblue),24(cdrom),25(floppy),27(sudo),29(audio)
$ firejail --nogroups
Parent pid 8704, child pid 8705
Child process initialized
$ id
uid=1000(netblue) gid=1000(netblue) groups=1000(netblue)
$
--noprofile
Do not use a security profile.
Example:
$ firejail
Reading profile /etc/firejail/default.profile
Parent pid 8553, child pid 8554
Child process initialized
[...]
$ firejail --noprofile
Parent pid 8553, child pid 8554
Child process initialized
[...]
--noroot
Install a user namespace with a single user - the current user. root user does not exist in the
new namespace. This option requires a Linux kernel version 3.8 or newer. The option is not
supported for --chroot and --overlay configurations, or for sandboxes started as root.
Example:
$ firejail --noroot
Parent pid 8553, child pid 8554
Child process initialized
$ ping google.com
ping: icmp open socket: Operation not permitted
$
--nonewprivs
Sets the NO_NEW_PRIVS prctl. This ensures that child processes cannot acquire new privileges
using execve(2); in particular, this means that calling a suid binary (or one with file
capabilities) does not result in an increase of privilege. This option is enabled by default if
seccomp filter is activated.
--nosound
Disable sound system.
Example:
$ firejail --nosound firefox
--notv Disable DVB (Digital Video Broadcasting) TV devices.
Example:
$ firejail --notv vlc
--novideo
Disable video devices.
--nowhitelist=dirname_or_filename
Disable whitelist for this directory or file.
--output=logfile
stdout logging and log rotation. Copy stdout to logfile, and keep the size of the file under 500KB
using log rotation. Five files with prefixes .1 to .5 are used in rotation.
Example:
$ firejail --output=sandboxlog /bin/bash
[...]
$ ls -l sandboxlog*
-rw-r--r-- 1 netblue netblue 333890 Jun 2 07:48 sandboxlog
-rw-r--r-- 1 netblue netblue 511488 Jun 2 07:48 sandboxlog.1
-rw-r--r-- 1 netblue netblue 511488 Jun 2 07:48 sandboxlog.2
-rw-r--r-- 1 netblue netblue 511488 Jun 2 07:48 sandboxlog.3
-rw-r--r-- 1 netblue netblue 511488 Jun 2 07:48 sandboxlog.4
-rw-r--r-- 1 netblue netblue 511488 Jun 2 07:48 sandboxlog.5
--output-stderr=logfile
Similar to --output, but stderr is also stored.
--overlay
Mount a filesystem overlay on top of the current filesystem. Unlike the regular filesystem
container, the system directories are mounted read-write. All filesystem modifications go into the
overlay. The overlay is stored in $HOME/.firejail/<PID> directory.
OverlayFS support is required in Linux kernel for this option to work. OverlayFS was officially
introduced in Linux kernel version 3.18. This option is not available on Grsecurity systems.
Example:
$ firejail --overlay firefox
--overlay-named=name
Mount a filesystem overlay on top of the current filesystem. Unlike the regular filesystem
container, the system directories are mounted read-write. All filesystem modifications go into the
overlay. The overlay is stored in $HOME/.firejail/<NAME> directory. The created overlay can be
reused between multiple sessions.
OverlayFS support is required in Linux kernel for this option to work. OverlayFS was officially
introduced in Linux kernel version 3.18. This option is not available on Grsecurity systems.
Example:
$ firejail --overlay-named=jail1 firefox
--overlay-tmpfs
Mount a filesystem overlay on top of the current filesystem. All filesystem modifications are
discarded when the sandbox is closed.
OverlayFS support is required in Linux kernel for this option to work. OverlayFS was officially
introduced in Linux kernel version 3.18. This option is not available on Grsecurity systems.
Example:
$ firejail --overlay-tmpfs firefox
--overlay-clean
Clean all overlays stored in $HOME/.firejail directory.
Example:
$ firejail --overlay-clean
--private
Mount new /root and /home/user directories in temporary filesystems. All modifications are
discarded when the sandbox is closed.
Example:
$ firejail --private firefox
--private=directory
Use directory as user home.
Example:
$ firejail --private=/home/netblue/firefox-home firefox
--private-home=file,directory
Build a new user home in a temporary filesystem, and copy the files and directories in the list in
the new home. All modifications are discarded when the sandbox is closed.
Example:
$ firejail --private-home=.mozilla firefox
--private-bin=file,file
Build a new /bin in a temporary filesystem, and copy the programs in the list. If no listed file
is found, /bin directory will be empty. The same directory is also bind-mounted over /sbin,
/usr/bin, /usr/sbin and /usr/local/bin. All modifications are discarded when the sandbox is
closed. File globbing is supported, see FILE GLOBBING section for more details.
Example:
$ firejail --private-bin=bash,sed,ls,cat
Parent pid 20841, child pid 20842
Child process initialized
$ ls /bin
bash cat ls sed
--private-lib=file,directory
This feature is currently under heavy development. Only amd64 platforms are supported at this
moment. The idea is to build a new /lib in a temporary filesystem, with only the library files
necessary to run the application. It could be as simple as:
$ firejail --private-lib galculator
but it gets complicated really fast:
$ firejail --private-lib=x86_64-linux-gnu/xed,x86_64-linux-gnu/gdk-
pixbuf-2.0,libenchant.so.1,librsvg-2.so.2 xed
The feature is integrated with --private-bin:
$ firejail --private-lib --private-bin=bash,ls,ps
$ ls /lib
ld-linux-x86-64.so.2 libgpg-error.so.0 libprocps.so.6 libsystemd.so.0
libc.so.6 liblz4.so.1 libpthread.so.0 libtinfo.so.5
libdl.so.2 liblzma.so.5 librt.so.1 x86_64-linux-gnu
libgcrypt.so.20 libpcre.so.3 libselinux.so.1
$ ps
PID TTY TIME CMD
1 pts/0 00:00:00 firejail
45 pts/0 00:00:00 bash
48 pts/0 00:00:00 ps
$
--private-dev
Create a new /dev directory. Only disc, dri, null, full, zero, tty, pts, ptmx, random, snd,
urandom, video, log and shm devices are available.
Example:
$ firejail --private-dev
Parent pid 9887, child pid 9888
Child process initialized
$ ls /dev
cdrom cdrw dri dvd dvdrw full log null ptmx pts random shm snd sr0 tty urandom
zero
$
--private-etc=file,directory
Build a new /etc in a temporary filesystem, and copy the files and directories in the list. If no
listed file is found, /etc directory will be empty. All modifications are discarded when the
sandbox is closed.
Example:
$ firejail --private-etc=group,hostname,localtime, \
nsswitch.conf,passwd,resolv.conf
--private-opt=file,directory
Build a new /opt in a temporary filesystem, and copy the files and directories in the list. If no
listed file is found, /opt directory will be empty. All modifications are discarded when the
sandbox is closed.
Example:
$ firejail --private-opt=firefox /opt/firefox/firefox
--private-srv=file,directory
Build a new /srv in a temporary filesystem, and copy the files and directories in the list. If no
listed file is found, /srv directory will be empty. All modifications are discarded when the
sandbox is closed.
Example:
# firejail --private-srv=www /etc/init.d/apache2 start
--private-tmp
Mount an empty temporary filesystem on top of /tmp directory whitelisting X11 and PulseAudio
sockets.
Example:
$ firejail --private-tmp
$ ls -al /tmp
drwxrwxrwt 4 nobody nogroup 80 Apr 30 11:46 .
drwxr-xr-x 30 nobody nogroup 4096 Apr 26 22:18 ..
drwx------ 2 nobody nogroup 4096 Apr 30 10:52 pulse-PKdhtXMmr18n
drwxrwxrwt 2 nobody nogroup 4096 Apr 30 10:52 .X11-unix
--profile=filename
Load a custom security profile from filename. For filename use an absolute path or a path relative
to the current path. For more information, see SECURITY PROFILES section below.
Example:
$ firejail --profile=myprofile
--profile.print=name|pid
Print the name of the profile file for the sandbox identified by name or or PID.
Example:
$ firejail --profile.print=browser
/etc/firejail/firefox.profile
--protocol=protocol,protocol,protocol
Enable protocol filter. The filter is based on seccomp and checks the first argument to socket
system call. Recognized values: unix, inet, inet6, netlink and packet. This option is not
supported for i386 architecture.
Example:
$ firejail --protocol=unix,inet,inet6 firefox
--protocol.print=name|pid
Print the protocol filter for the sandbox identified by name or PID.
Example:
$ firejail --name=mybrowser firefox &
$ firejail --protocol.print=mybrowser
unix,inet,inet6,netlink
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --protocol.print=3272
unix,inet,inet6,netlink
--put=name|pid src-filename dest-filename
Put a file in sandbox container, see FILE TRANSFER section for more details.
--quiet
Turn off Firejail's output.
--read-only=dirname_or_filename
Set directory or file read-only. File globbing is supported, see FILE GLOBBING section for more
details.
Example:
$ firejail --read-only=~/.mozilla firefox
A short note about mixing --whitelist and --read-only options. Whitelisted directories should be
made read-only independently. Making a parent directory read-only, will not make the whitelist
read-only. Example:
$ firejail --whitelist=~/work --read-only=~ --read-only=~/work
--read-write=dirname_or_filename
Set directory or file read-write. Only files or directories belonging to the current user are
allowed for this operation. File globbing is supported, see FILE GLOBBING section for more
details. Example:
$ mkdir ~/test
$ touch ~/test/a
$ firejail --read-only=~/test --read-write=~/test/a
--rlimit-as=number
Set the maximum size of the process's virtual memory (address space) in bytes.
--rlimit-cpu=number
Set the maximum limit, in seconds, for the amount of CPU time each sandboxed process can consume.
When the limit is reached, the processes are killed.
The CPU limit is a limit on CPU seconds rather than elapsed time. CPU seconds is basically how
many seconds the CPU has been in use and does not necessarily directly relate to the elapsed time.
Linux kernel keeps track of CPU seconds for each process independently.
--rlimit-fsize=number
Set the maximum file size that can be created by a process.
--rlimit-nofile=number
Set the maximum number of files that can be opened by a process.
--rlimit-nproc=number
Set the maximum number of processes that can be created for the real user ID of the calling
process.
--rlimit-sigpending=number
Set the maximum number of pending signals for a process.
--rmenv=name
Remove environment variable in the new sandbox.
Example:
$ firejail --rmenv=DBUS_SESSION_BUS_ADDRESS
--scan ARP-scan all the networks from inside a network namespace. This makes it possible to detect
macvlan kernel device drivers running on the current host.
Example:
$ firejail --net=eth0 --scan
--seccomp
Enable seccomp filter and blacklist the syscalls in the default list (@default). The default list
is as follows: mount, umount2, ptrace, kexec_load, kexec_file_load, name_to_handle_at,
open_by_handle_at, create_module, init_module, finit_module, delete_module, iopl, ioperm,
ioprio_set, swapon, swapoff, syslog, process_vm_readv, process_vm_writev, sysfs,_sysctl, adjtimex,
clock_adjtime, lookup_dcookie, perf_event_open, fanotify_init, kcmp, add_key, request_key, keyctl,
uselib, acct, modify_ldt, pivot_root, io_setup, io_destroy, io_getevents, io_submit, io_cancel,
remap_file_pages, mbind, set_mempolicy, migrate_pages, move_pages, vmsplice, chroot, tuxcall,
reboot, mfsservctl, get_kernel_syms, bpf, clock_settime, personality, process_vm_writev,
query_module, settimeofday, stime, umount, userfaultfd, ustat, vm86, vm86old, afs_syscall,
bdflush, break, ftime, getpmsg, gtty, lock, mpx, pciconfig_iobase, pciconfig_read,
pciconfig_write, prof, profil, putpmsg, rtas, s390_runtime_instr, s390_mmio_read, s390_mmio_write,
security, setdomainname, sethostname, sgetmask, ssetmask, stty, subpage_prot, switch_endian,
ulimit, vhangup and vserver.
To help creating useful seccomp filters more easily, the following system call groups are defined:
@clock, @cpu-emulation, @debug, @default, @default-nodebuggers, @default-keep, @module, @obsolete,
@privileged, @raw-io, @reboot, @resources and @swap. In addtion, a system call can be specified by
its number instead of name with prefix $, so for example $165 would be equal to mount on i386.
System architecture is strictly imposed only if flag --seccomp.block-secondary is used. The filter
is applied at run time only if the correct architecture was detected. For the case of I386 and
AMD64 both 32-bit and 64-bit filters are installed.
Firejail will print seccomp violations to the audit log if the kernel was compiled with audit
support (CONFIG_AUDIT flag).
Example:
$ firejail --seccomp
--seccomp=syscall,@group
Enable seccomp filter, blacklist the default list (@default) and the syscalls or syscall groups
specified by the command.
Example:
$ firejail --seccomp=utime,utimensat,utimes firefox
$ firejail --seccomp=@clock,mkdir,unlinkat transmission-gtk
Instead of dropping the syscall, a specific error number can be returned using syscall:errorno
syntax.
Example: $ firejail --seccomp=unlinkat:ENOENT,utimensat,utimes
Parent pid 10662, child pid 10663
Child process initialized
$ touch testfile
$ rm testfile
rm: cannot remove `testfile': Operation not permitted
If the blocked system calls would also block Firejail from operating, they are handled by adding a
preloaded library which performs seccomp system calls later.
Example:
$ firejail --noprofile --shell=none --seccomp=execve bash
Parent pid 32751, child pid 32752
Post-exec seccomp protector enabled
list in: execve, check list: @default-keep prelist: (null), postlist: execve
Child process initialized in 46.44 ms
$ ls
Bad system call
--seccomp.block_secondary
Enable seccomp filter and filter system call architectures so that only the native architecture is
allowed. For example, on amd64, i386 and x32 system calls are blocked as well as changing the
execution domain with personality(2) system call.
--seccomp.drop=syscall,@group
Enable seccomp filter, and blacklist the syscalls or the syscall groups specified by the command.
Example:
$ firejail --seccomp.drop=utime,utimensat,utimes,@clock
Instead of dropping the syscall, a specific error number can be returned using syscall:errorno
syntax.
Example:
$ firejail --seccomp.drop=unlinkat:ENOENT,utimensat,utimes
Parent pid 10662, child pid 10663
Child process initialized
$ touch testfile
$ rm testfile
rm: cannot remove `testfile': Operation not permitted
--seccomp.keep=syscall,syscall,syscall
Enable seccomp filter, and whitelist the syscalls specified by the command. The system calls
needed by Firejail (group @default-keep: prctl, execve) are handled with the preload library.
Example:
$ firejail --shell=none --seccomp.keep=poll,select,[...] transmission-gtk
--seccomp.print=name|PID
Print the seccomp filter for the sandbox identified by name or PID.
Example:
$ firejail --name=browser firefox &
$ firejail --seccomp.print=browser
SECCOMP Filter:
VALIDATE_ARCHITECTURE
EXAMINE_SYSCALL
BLACKLIST 165 mount
BLACKLIST 166 umount2
BLACKLIST 101 ptrace
BLACKLIST 246 kexec_load
BLACKLIST 304 open_by_handle_at
BLACKLIST 175 init_module
BLACKLIST 176 delete_module
BLACKLIST 172 iopl
BLACKLIST 173 ioperm
BLACKLIST 167 swapon
BLACKLIST 168 swapoff
BLACKLIST 103 syslog
BLACKLIST 310 process_vm_readv
BLACKLIST 311 process_vm_writev
BLACKLIST 133 mknod
BLACKLIST 139 sysfs
BLACKLIST 156 _sysctl
BLACKLIST 159 adjtimex
BLACKLIST 305 clock_adjtime
BLACKLIST 212 lookup_dcookie
BLACKLIST 298 perf_event_open
BLACKLIST 300 fanotify_init
RETURN_ALLOW
$
--shell=none
Run the program directly, without a user shell.
Example:
$ firejail --shell=none script.sh
--shell=program
Set default user shell. Use this shell to run the application using -c shell option. For example
"firejail --shell=/bin/dash firefox" will start Mozilla Firefox as "/bin/dash -c firefox". By
default Bash shell (/bin/bash) is used. Options such as --zsh and --csh can also set the default
shell.
Example: $firejail --shell=/bin/dash script.sh
--shutdown=name|PID
Shutdown the sandbox identified by name or PID.
Example:
$ firejail --name=mygame --caps.drop=all warzone2100 &
$ firejail --shutdown=mygame
Example:
$ firejail --list
3272:netblue:firejail --private firefox
$ firejail --shutdown=3272
--timeout=hh:mm:ss
Kill the sandbox automatically after the time has elapsed. The time is specified in
hours/minutes/seconds format.
$ firejail --timeout=01:30:00 firefox
--tmpfs=dirname
Mount a tmpfs filesystem on directory dirname. This option is available only when running the
sandbox as root. File globbing is supported, see FILE GLOBBING section for more details.
Example:
# firejail --tmpfs=/var
--top Monitor the most CPU-intensive sandboxes, see MONITORING section for more details.
Example:
$ firejail --top
--trace
Trace open, access and connect system calls.
Example:
$ firejail --trace wget -q www.debian.org
Reading profile /etc/firejail/wget.profile
3:wget:fopen64 /etc/wgetrc:0x5c8e8ce6c0
3:wget:fopen /etc/hosts:0x5c8e8cfb70
3:wget:socket AF_INET SOCK_DGRAM IPPROTO_IP:3
3:wget:connect 3 8.8.8.8 port 53:0
3:wget:socket AF_INET SOCK_STREAM IPPROTO_IP:3
3:wget:connect 3 130.89.148.14 port 80:0
3:wget:fopen64 index.html:0x5c8e8d1a60
parent is shutting down, bye...
--tracelog
This option enables auditing blacklisted files and directories. A message is sent to syslog in
case the file or the directory is accessed.
Example:
$ firejail --tracelog firefox
Sample messages:
$ sudo tail -f /var/log/syslog
[...]
Dec 3 11:43:25 debian firejail[70]: blacklist violation - sandbox 26370, exe firefox, syscall
open64, path /etc/shadow
Dec 3 11:46:17 debian firejail[70]: blacklist violation - sandbox 26370, exe firefox, syscall
opendir, path /boot
[...]
--tree Print a tree of all sandboxed processes, see MONITORING section for more details.
Example:
$ firejail --tree
11903:netblue:firejail iceweasel
11904:netblue:iceweasel
11957:netblue:/usr/lib/iceweasel/plugin-container
11969:netblue:firejail --net=eth0 transmission-gtk
11970:netblue:transmission-gtk
--version
Print program version and exit.
Example:
$ firejail --version
firejail version 0.9.27
--veth-name=name
Use this name for the interface connected to the bridge for --net=bridge_interface commands,
instead of the default one.
Example:
$ firejail --net=br0 --veth-name=if0
--whitelist=dirname_or_filename
Whitelist directory or file. A temporary file system is mounted on the top directory, and the
whitelisted files are mount-binded inside. Modifications to whitelisted files are persistent,
everything else is discarded when the sandbox is closed. The top directory could be user home,
/dev, /media, /mnt, /opt, /srv, /var, and /tmp.
Symbolic link handling: with the exception of user home, both the link and the real file should be
in the same top directory. For user 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"
--writable-etc
Mount /etc directory read-write.
Example:
$ sudo firejail --writable-etc
--writable-run-user
Disable the default blacklisting of /run/user/$UID/systemd and /run/user/$UID/gnupg.
Example:
$ sudo firejail --writable-run-user
--writable-var
Mount /var directory read-write.
Example:
$ sudo firejail --writable-var
--writable-var-log
Use the real /var/log directory, not a clone. By default, a tmpfs is mounted on top of /var/log
directory, and a skeleton filesystem is created based on the original /var/log.
Example:
$ sudo firejail --writable-var-log
--x11 Sandbox the application using Xpra, Xephyr, Xvfb or Xorg security extension. The sandbox will
prevents screenshot and keylogger applications started inside the sandbox from accessing clients
running outside the sandbox. Firejail will try first Xpra, and if Xpra is not installed on the
system, it will try to find Xephyr. If all fails, Firejail will not attempt to use Xvfb or X11
security extension.
Xpra, Xephyr and Xvfb modes require a network namespace to be instantiated in order to disable X11
abstract Unix socket. If this is not possible, the user can disable the abstract socket by adding
"-nolisten local" on Xorg command line at system level.
Example:
$ firejail --x11 --net=eth0 firefox
--x11=none
Blacklist /tmp/.X11-unix directory, ${HOME}/.Xauthority and the file specified in ${XAUTHORITY}
environment variable. Remove DISPLAY and XAUTHORITY environment variables. Stop with error
message if X11 abstract socket will be accessible in jail.
--x11=xephyr
Start Xephyr and attach the sandbox to this server. Xephyr is a display server implementing the
X11 display server protocol. A network namespace needs to be instantiated in order to deny access
to X11 abstract Unix domain socket.
Xephyr runs in a window just like any other X11 application. The default window size is 800x600.
This can be modified in /etc/firejail/firejail.config file.
The recommended way to use this feature is to run a window manager inside the sandbox. A security
profile for OpenBox is provided.
Xephyr is developed by Xorg project. On Debian platforms it is installed with the command sudo
apt-get install xserver-xephyr. This feature is not available when running as root.
Example:
$ firejail --x11=xephyr --net=eth0 openbox
--x11=xorg
Sandbox the application using the untrusted mode implemented by X11 security extension. The
extension is available in Xorg package and it is installed by default on most Linux distributions.
It provides support for a simple trusted/untrusted connection model. Untrusted clients are
restricted in certain ways to prevent them from reading window contents of other clients, stealing
input events, etc.
The untrusted mode has several limitations. A lot of regular programs assume they are a trusted
X11 clients and will crash or lock up when run in untrusted mode. Chromium browser and xterm are
two examples. Firefox and transmission-gtk seem to be working fine. A network namespace is not
required for this option.
Example:
$ firejail --x11=xorg firefox
--x11=xpra
Start Xpra (https://xpra.org) and attach the sandbox to this server. Xpra is a persistent remote
display server and client for forwarding X11 applications and desktop screens. A network
namespace needs to be instantiated in order to deny access to X11 abstract Unix domain socket.
On Debian platforms Xpra is installed with the command sudo apt-get install xpra. This feature is
not available when running as root.
Example:
$ firejail --x11=xpra --net=eth0 firefox
--x11=xvfb
Start Xvfb X11 server and attach the sandbox to this server. Xvfb, short for X virtual
framebuffer, performs all graphical operations in memory without showing any screen output. Xvfb
is mainly used for remote access and software testing on headless servers.
On Debian platforms Xvfb is installed with the command sudo apt-get install xvfb. This feature is
not available when running as root.
Example: remote VNC access
On the server we start a sandbox using Xvfb and openbox window manager. The default size of Xvfb
screen is 800x600 - it can be changed in /etc/firejail/firejail.config (xvfb-screen). Some sort of
networking (--net) is required in order to isolate the abstract sockets used by other X servers.
$ firejail --net=none --x11=xvfb openbox
*** Attaching to Xvfb display 792 ***
Reading profile /etc/firejail/openbox.profile
Reading profile /etc/firejail/disable-common.inc
Reading profile /etc/firejail/disable-common.local
Parent pid 5400, child pid 5401
On the server we also start a VNC server and attach it to the display handled by our Xvfb server
(792).
$ x11vnc -display :792
On the client machine we start a VNC viewer and use it to connect to our server:
$ vncviewer
--xephyr-screen=WIDTHxHEIGHT
Set screen size for --x11=xephyr. The setting will overwrite the default set in
/etc/firejail/firejail.config for the current sandbox. Run xrandr to get a list of supported
resolutions on your computer.
Example:
$ firejail --net=eth0 --x11=xephyr --xephyr-screen=640x480 firefox
--zsh Use /usr/bin/zsh as default user shell.
Example:
$ firejail --zsh
DESKTOP INTEGRATION
A symbolic link to /usr/bin/firejail under the name of a program, will start the program in Firejail
sandbox. The symbolic link should be placed in the first $PATH position. On most systems, a good place
is /usr/local/bin directory. Example:
Make a firefox symlink to /usr/bin/firejail:
$ ln -s /usr/bin/firejail /usr/local/bin/firefox
Verify $PATH
$ which -a firefox
/usr/local/bin/firefox
/usr/bin/firefox
Starting firefox in this moment, automatically invokes “firejail firefox”.
This works for clicking on desktop environment icons, menus etc. Use "firejail --tree" to verify the
program is sandboxed.
$ firejail --tree
1189:netblue:firejail firefox
1190:netblue:firejail firefox
1220:netblue:/bin/sh -c "/usr/lib/firefox/firefox"
1221:netblue:/usr/lib/firefox/firefox
We provide a tool that automates all this integration, please see man 1 firecfg for more details.
FILE GLOBBING
Globbing is the operation that expands a wildcard pattern into the list of pathnames matching the
pattern. Matching is defined by:
- '?' matches any character
- '*' matches any string
- '[' denotes a range of characters
The gobing feature is implemented using glibc glob command. For more information on the wildcard syntax
see man 7 glob.
The following command line options are supported: --blacklist, --private-bin, --noexec, --read-only,
--read-write, and --tmpfs.
Examples:
$ firejail --private-bin=sh,bash,python*
$ firejail --blacklist=~/dir[1234]
$ firejail --read-only=~/dir[1-4]
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 features inspired by kernel-based
Grsecurity:
- Prevent information leakage in /proc and /sys directories. The resulting filesystem 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.
- Allow access to files only in the following standard directories: /bin, /dev, /etc, /home,
/lib*, /media, /mnt, /opt, /proc, /root, /run, /sbin, /srv, /sys, /tmp, /usr, and /var
- 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. This feature is available only on Ubuntu
kernels.
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
FILE TRANSFER
These features allow the user to inspect the filesystem container of an existing sandbox and transfer
files from the container to the host filesystem.
--get=name|pid filename
Retrieve the container file and store it on the host in the current working directory. The
container is specified by name or PID.
--ls=name|pid dir_or_filename
List container files. The container is specified by name or PID.
--put=name|pid src-filename dest-filename
Put src-filename in sandbox container. The container is specified by name or PID.
Examples:
$ firejail --name=mybrowser --private firefox
$ firejail --ls=mybrowser ~/Downloads
drwxr-xr-x netblue netblue 4096 .
drwxr-xr-x netblue netblue 4096 ..
-rw-r--r-- netblue netblue 7847 x11-x305.png
-rw-r--r-- netblue netblue 6800 x11-x642.png
-rw-r--r-- netblue netblue 34139 xpra-clipboard.png
$ firejail --get=mybrowser ~/Downloads/xpra-clipboard.png
$ firejail --put=mybrowser xpra-clipboard.png ~/Downloads/xpra-clipboard.png
TRAFFIC SHAPING
Network bandwidth is an expensive resource shared among all sandboxes running on a system. Traffic
shaping allows the user to increase network performance by controlling the amount of data that flows into
and out of the sandboxes.
Firejail implements a simple rate-limiting shaper based on Linux command tc. The shaper works at sandbox
level, and can be used only for sandboxes configured with new network namespaces.
Set rate-limits:
$ firejail --bandwidth=name|pid set network download upload
Clear rate-limits:
$ firejail --bandwidth=name|pid clear network
Status:
$ firejail --bandwidth=name|pid status
where:
name - sandbox name
pid - sandbox pid
network - network interface as used by --net option
download - download speed in KB/s (kilobyte per second)
upload - upload speed in KB/s (kilobyte per second)
Example:
$ firejail --name=mybrowser --net=eth0 firefox &
$ firejail --bandwidth=mybrowser set eth0 80 20
$ firejail --bandwidth=mybrowser status
$ firejail --bandwidth=mybrowser clear eth0
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.
MONITORING
Option --list prints a list of all sandboxes. The format for each process entry is as follows:
PID:USER:Command
Option --tree prints the tree of processes running in the sandbox. The format for each process entry is
as follows:
PID:USER:Command
Option --top is similar to the UNIX top command, however it applies only to sandboxes.
Option --netstats prints network statistics for active sandboxes installing new network namespaces.
Listed below are the available fields (columns) in alphabetical order for --top and --netstat options:
Command
Command used to start the sandbox.
CPU% CPU usage, the sandbox share of the elapsed CPU time since the last screen update
PID Unique process ID for the task controlling the sandbox.
Prcs Number of processes running in sandbox, including the controlling process.
RES Resident Memory Size (KiB), sandbox non-swapped physical memory. It is a sum of the RES values
for all processes running in the sandbox.
RX(KB/s)
Network receive speed.
SHR Shared Memory Size (KiB), it reflects memory shared with other processes. It is a sum of the SHR
values for all processes running in the sandbox, including the controlling process.
TX(KB/s)
Network transmit speed.
Uptime Sandbox running time in hours:minutes:seconds format.
User The owner of the sandbox.
SECURITY PROFILES
Several command line options can be passed to the program using profile files. Firejail chooses the
profile file as follows:
1. If a profile file is provided by the user with --profile option, the profile file is loaded. Example:
$ firejail --profile=/home/netblue/icecat.profile icecat
Reading profile /home/netblue/icecat.profile
[...]
2. If a profile file with the same name as the application is present in ~/.config/firejail directory or
in /etc/firejail, the profile is loaded. ~/.config/firejail takes precedence over /etc/firejail. Example:
$ firejail icecat
Command name #icecat#
Found icecat profile in /home/netblue/.config/firejail directory
Reading profile /home/netblue/.config/firejail/icecat.profile
[...]
3. Use default.profile file if the sandbox is started by a regular user, or server.profile file if the
sandbox is started by root. Firejail looks for these files in ~/.config/firejail directory, followed by
/etc/firejail directory. To disable default profile loading, use --noprofile command option. Example:
$ firejail
Reading profile /etc/firejail/default.profile
Parent pid 8553, child pid 8554
Child process initialized
[...]
$ firejail --noprofile
Parent pid 8553, child pid 8554
Child process initialized
[...]
See man 5 firejail-profile for profile file syntax information.
RESTRICTED SHELL
To configure a restricted shell, replace /bin/bash with /usr/bin/firejail in /etc/passwd file for each user that needs to be restricted. Alternatively, you can specify /usr/bin/firejail in adduser command: adduser --shell /usr/bin/firejail username Additional arguments passed to firejail executable upon login are declared in /etc/firejail/login.users file.
EXAMPLES
firejail
Sandbox a regular /bin/bash session.
firejail firefox
Start Mozilla Firefox.
firejail --debug firefox
Debug Firefox sandbox.
firejail --private firefox
Start Firefox with a new, empty home directory.
firejail --net=none vlc
Start VLC in an unconnected network namespace.
firejail --net=eth0 firefox
Start Firefox in a new network namespace. An IP address is assigned automatically.
firejail --net=br0 --ip=10.10.20.5 --net=br1 --net=br2
Start a /bin/bash session in a new network namespace and connect it to br0, br1, and br2 host
bridge devices. IP addresses are assigned automatically for the interfaces connected to br1 and b2
firejail --list
List all sandboxed processes.
LICENSE
This program is free software; you can redistribute it and/or modify it under the terms of the GNU
General Public License as published by the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
Homepage: https://firejail.wordpress.com
SEE ALSO
firemon(1), firecfg(1), firejail-profile(5), firejail-login(5)