FIREJAIL(1) firejail man page FIREJAIL(1)
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 applica‐
tions 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 PRO‐
FILES 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 process‐
ing.
--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/fire‐
fox.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. If the
sandbox is started as a regular user, default seccomp and capa‐
bilities filters are enabled.
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.appim‐
age
--apparmor.print=name|pid
Print the AppArmor confinement status for the sandbox identi‐
fied by name or by PID.
Example:
$ firejail --apparmor.print=browser
5074:netblue:/usr/bin/firejail /usr/bin/firefox-esr
AppArmor: firejail-default enforce
--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 pro‐
gram 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 ~/Videos/test.mp4
--build=profile-file
The command builds a whitelisted profile, and saves it in pro‐
file-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 sup‐
ported 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 privi‐
leges can be enabled or disabled independently, thus restrict‐
ing 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_MOD‐
ULE, 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.
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
--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 soft‐
ware build and exit.
Example:
$ firejail --debug-caps
--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 soft‐
ware 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 names‐
pace.
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
--fs.print=name|pid
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.
-?, --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
$ firejail --ignore="net eth0" firefox
--interface=interface
Move interface in a new network namespace. Up to four --inter‐
face options can be specified. Note: wlan devices are not sup‐
ported 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 sand‐
box.
Example:
$ firejail --net=eth0 --ip=none
If the corresponding interface doesn't have an IP address con‐
figured, 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 fil‐
ters are configured for the new process the same they are con‐
figured 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 sand‐
box. 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/fire‐
jail/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 sand‐
box
1: lo: 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: 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.
--keep-dev-shm
/dev/shm directory is untouched (even with --private-dev)
Example:
$ firejail --keep-dev-shm --private-dev
--keep-var-tmp
/var/tmp directory is untouched.
Example:
$ firejail --keep-var-tmp
--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:browser:firejail firefox
7056:netblue:torrent: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. This option is not supported for wireless inter‐
faces.
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 map‐
pings 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 plat‐
forms 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 --shut‐
down, 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 automati‐
cally 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 options can be
specified.
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|wireless_interface
Enable a new network namespace and connect it to this ethernet
interface using the standard Linux macvlan|ipvaln 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 options can be
specified. Support for ipvlan driver was introduced in Linux
kernel 3.19.
Example:
$ firejail --net=eth0 --ip=192.168.1.80 --dns=8.8.8.8 firefox
$ firejail --net=wlan0 firefox
--net=tap_interface
Enable a new network namespace and connect it to this ethernet
tap interface using the standard Linux macvlan driver. If the
tap interface is not configured, the sandbox will not try to
configure the interface inside the sandbox. Please use --ip,
--netmask and --defaultgw to specify the configuration.
Example:
$ firejail --net=tap0 --ip=10.10.20.80 --netmask=255.255.255.0
--defaultgw=10.10.20.1 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.
--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 applica‐
tions. 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
--netmask=address
Use this option when you want to assign an IP address in a new
namespace and the parent interface specified by --net is not
configured. An IP address and a default gateway address also
have to be added. By default the new namespace interface comes
without IP address and default gateway configured. Example:
$ sudo /sbin/brctl addbr br0
$ sudo /sbin/ifconfig br0 up
$ firejail --ip=10.10.20.67 --netmask=255.255.255.0
--defaultgw=10.10.20.1
--netns=name
Run the program in a named, persistent network namespace.
These can be created and configured using "ip netns".
--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
--nodbus
Disable D-Bus access. Only the regular UNIX socket is handled
by this command. To disable the abstract socket you would need
to request a new network namespace using --net command. Another
option is to remove unix from --protocol set.
Example:
$ firejail --nodbus --net=none
--nodvd
Disable DVD and audio CD devices.
Example:
$ firejail --nodvd
--noexec=dirname_or_filename
Remount directory or file noexec, nodev and nosuid. File glob‐
bing 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, supplemen‐
tary 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(net‐
blue),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 capa‐
bilities) 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
--noautopulse
Disable automatic ~/.config/pulse init, for complex setups such
as remote pulse servers or non-standard socket paths.
Example:
$ firejail --noautopulse firefox
--notv Disable DVB (Digital Video Broadcasting) TV devices.
Example:
$ firejail --notv vlc
--nou2f
Disable U2F devices.
Example:
$ firejail --nou2f
--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. Directories /run, /tmp and /dev are not covered
by the overlay. The overlay is stored in $HOME/.firejail/
directory. If the sandbox is started as a regular user,
default seccomp and capabilities filters are enabled.
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 sys‐
tems.
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. Directories /run, /tmp and /dev are not covered
by the overlay. The overlay is stored in $HOME/.firejail/
directory. The created overlay can be reused between multiple
sessions. If the sandbox is started as a regular user, default
seccomp and capabilities filters are enabled.
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 sys‐
tems.
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. Directories /run, /tmp and /dev are not covered by the
overlay. If the sandbox is started as a regular user, default
seccomp and capabilities filters are enabled.
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 sys‐
tems.
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 modifi‐
cations are discarded when the sandbox is closed.
Example:
$ firejail --private-home=.mozilla firefox
--private-cache
Mount an empty temporary filesystem on top of the .cache direc‐
tory in user home. All modifications are discarded when the
sandbox is closed.
Example:
$ firejail --private-cache openbox
--private-bin=file,file
Build a new /bin in a temporary filesystem, and copy the pro‐
grams 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 modifica‐
tions 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 libsys‐
temd.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 ran‐
dom 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-PKd‐
htXMmr18n
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: _sysctl, acct,
add_key, adjtimex, afs_syscall, bdflush, bpf, break, chroot,
clock_adjtime, clock_settime, create_module, delete_module,
fanotify_init, finit_module, ftime, get_kernel_syms, getpmsg,
gtty, init_module, io_cancel, io_destroy, io_getevents, io_set‐
up, io_submit, ioperm, iopl, ioprio_set, kcmp, kexec_file_load,
kexec_load, keyctl, lock, lookup_dcookie, mbind, mfsservctl,
migrate_pages, modify_ldt, mount, move_pages, mpx, name_to_han‐
dle_at, open_by_handle_at, pciconfig_iobase, pciconfig_read,
pciconfig_write, perf_event_open, personality, pivot_root,
process_vm_readv, process_vm_writev, process_vm_writev, prof,
profil, ptrace, putpmsg, query_module, reboot,
remap_file_pages, request_key, rtas, s390_mmio_read,
s390_mmio_write, s390_runtime_instr, security, set_mempolicy,
setdomainname, sethostname, settimeofday, sgetmask, ssetmask,
stime, stty, subpage_prot, swapoff, swapon, switch_endian,
sysfs, syslog, tuxcall, ulimit, umount, umount2, uselib, user‐
faultfd, ustat, vhangup, vm86, vm86old, vmsplice and vserver.
To help creating useful seccomp filters more easily, the fol‐
lowing 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 --sec‐
comp.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 chang‐
ing 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,[...] trans‐
mission-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
line OP JT JF K
=================================
0000: 20 00 00 00000004 ld data.architecture
0001: 15 01 00 c000003e jeq ARCH_64 0003 (false 0002)
0002: 06 00 00 7fff0000 ret ALLOW
0003: 20 00 00 00000000 ld data.syscall-number
0004: 35 01 00 40000000 jge X32_ABI true:0006 (false 0005)
0005: 35 01 00 00000000 jge read 0007 (false 0006)
0006: 06 00 00 00050001 ret ERRNO(1)
0007: 15 41 00 0000009a jeq modify_ldt 0049 (false 0008)
0008: 15 40 00 000000d4 jeq lookup_dcookie 0049 (false 0009)
0009: 15 3f 00 0000012a jeq perf_event_open 0049 (false
000a)
000a: 15 3e 00 00000137 jeq process_vm_writev 0049 (false
000b)
000b: 15 3d 00 0000009c jeq _sysctl 0049 (false 000c)
000c: 15 3c 00 000000b7 jeq afs_syscall 0049 (false 000d)
000d: 15 3b 00 000000ae jeq create_module 0049 (false 000e)
000e: 15 3a 00 000000b1 jeq get_kernel_syms 0049 (false
000f)
000f: 15 39 00 000000b5 jeq getpmsg 0049 (false 0010)
0010: 15 38 00 000000b6 jeq putpmsg 0049 (false 0011)
0011: 15 37 00 000000b2 jeq query_module 0049 (false 0012)
0012: 15 36 00 000000b9 jeq security 0049 (false 0013)
0013: 15 35 00 0000008b jeq sysfs 0049 (false 0014)
0014: 15 34 00 000000b8 jeq tuxcall 0049 (false 0015)
0015: 15 33 00 00000086 jeq uselib 0049 (false 0016)
0016: 15 32 00 00000088 jeq ustat 0049 (false 0017)
0017: 15 31 00 000000ec jeq vserver 0049 (false 0018)
0018: 15 30 00 0000009f jeq adjtimex 0049 (false 0019)
0019: 15 2f 00 00000131 jeq clock_adjtime 0049 (false 001a)
001a: 15 2e 00 000000e3 jeq clock_settime 0049 (false 001b)
001b: 15 2d 00 000000a4 jeq settimeofday 0049 (false 001c)
001c: 15 2c 00 000000b0 jeq delete_module 0049 (false 001d)
001d: 15 2b 00 00000139 jeq finit_module 0049 (false 001e)
001e: 15 2a 00 000000af jeq init_module 0049 (false 001f)
001f: 15 29 00 000000ad jeq ioperm 0049 (false 0020)
0020: 15 28 00 000000ac jeq iopl 0049 (false 0021)
0021: 15 27 00 000000f6 jeq kexec_load 0049 (false 0022)
0022: 15 26 00 00000140 jeq kexec_file_load 0049 (false
0023)
0023: 15 25 00 000000a9 jeq reboot 0049 (false 0024)
0024: 15 24 00 000000a7 jeq swapon 0049 (false 0025)
0025: 15 23 00 000000a8 jeq swapoff 0049 (false 0026)
0026: 15 22 00 000000a3 jeq acct 0049 (false 0027)
0027: 15 21 00 00000141 jeq bpf 0049 (false 0028)
0028: 15 20 00 000000a1 jeq chroot 0049 (false 0029)
0029: 15 1f 00 000000a5 jeq mount 0049 (false 002a)
002a: 15 1e 00 000000b4 jeq nfsservctl 0049 (false 002b)
002b: 15 1d 00 0000009b jeq pivot_root 0049 (false 002c)
002c: 15 1c 00 000000ab jeq setdomainname 0049 (false 002d)
002d: 15 1b 00 000000aa jeq sethostname 0049 (false 002e)
002e: 15 1a 00 000000a6 jeq umount2 0049 (false 002f)
002f: 15 19 00 00000099 jeq vhangup 0049 (false 0030)
0030: 15 18 00 000000ee jeq set_mempolicy 0049 (false 0031)
0031: 15 17 00 00000100 jeq migrate_pages 0049 (false 0032)
0032: 15 16 00 00000117 jeq move_pages 0049 (false 0033)
0033: 15 15 00 000000ed jeq mbind 0049 (false 0034)
0034: 15 14 00 00000130 jeq open_by_handle_at 0049 (false
0035)
0035: 15 13 00 0000012f jeq name_to_handle_at 0049 (false
0036)
0036: 15 12 00 000000fb jeq ioprio_set 0049 (false 0037)
0037: 15 11 00 00000067 jeq syslog 0049 (false 0038)
0038: 15 10 00 0000012c jeq fanotify_init 0049 (false 0039)
0039: 15 0f 00 00000138 jeq kcmp 0049 (false 003a)
003a: 15 0e 00 000000f8 jeq add_key 0049 (false 003b)
003b: 15 0d 00 000000f9 jeq request_key 0049 (false 003c)
003c: 15 0c 00 000000fa jeq keyctl 0049 (false 003d)
003d: 15 0b 00 000000ce jeq io_setup 0049 (false 003e)
003e: 15 0a 00 000000cf jeq io_destroy 0049 (false 003f)
003f: 15 09 00 000000d0 jeq io_getevents 0049 (false 0040)
0040: 15 08 00 000000d1 jeq io_submit 0049 (false 0041)
0041: 15 07 00 000000d2 jeq io_cancel 0049 (false 0042)
0042: 15 06 00 000000d8 jeq remap_file_pages 0049 (false
0043)
0043: 15 05 00 00000116 jeq vmsplice 0049 (false 0044)
0044: 15 04 00 00000087 jeq personality 0049 (false 0045)
0045: 15 03 00 00000143 jeq userfaultfd 0049 (false 0046)
0046: 15 02 00 00000065 jeq ptrace 0049 (false 0047)
0047: 15 01 00 00000136 jeq process_vm_readv 0049 (false
0048)
0048: 06 00 00 7fff0000 ret ALLOW
0049: 06 00 01 00000000 ret KILL
$
--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.
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 sec‐
tion 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
--tunnel[=devname]
Connect the sandbox to a network overlay/VPN tunnel created by
firetunnel utility. This options tries first the client side of
the tunnel. If this fails, it tries the server side. If multi‐
ple tunnels are active, please specify the tunnel device using
--tunnel=devname.
The available tunnel devices are listed in /etc/firetunnel
directory, one file for each device. The files are regular
firejail profile files containing the network configuration,
and are created and managed by firetunnel utility. By default
ftc is the client-side device and fts is the server-side
device. For more information please see man 1 firetunnel.
Example:
$ firejail --tunnel firefox
--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 persis‐
tent, everything else is discarded when the sandbox is closed.
The top directory could be user home, /dev, /etc, /media, /mnt,
/opt, /srv, /sys/module, /usr/share, /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 secu‐
rity extension. The sandbox will prevents screenshot and key‐
logger 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 man‐
ager 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 distribu‐
tions. It provides support for a simple trusted/untrusted con‐
nection 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 run‐
ning 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 run‐
ning 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 con‐
nect 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 cur‐
rent sandbox. Run xrandr to get a list of supported resolutions
on your computer.
Example:
$ firejail --net=eth0 --x11=xephyr --xephyr-screen=640x480
firefox
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 “fire‐
jail 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, --pri‐
vate-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 fea‐
tures 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 directo‐
ries: /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 secu‐
rity 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 speci‐
fied 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 net‐
work 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 com‐
mand 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:Sandbox Name:Command
Option --tree prints the tree of processes running in the sandbox. The
format for each process entry is as follows:
PID:USER:Sandbox Name: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 control‐
ling process.
RES Resident Memory Size (KiB), sandbox non-swapped physical mem‐
ory. It is a sum of the RES values for all processes running
in the sandbox.
RX(KB/s)
Network receive speed.
Sandbox Name
The name of the sandbox, if any.
SHR Shared Memory Size (KiB), it reflects memory shared with other
processes. It is a sum of the SHR values for all processes run‐
ning 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 pro‐
file 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. Exam‐
ple:
$ firejail icecat
Command name #icecat#
Found icecat profile in /home/netblue/.config/firejail direc‐
tory
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. Fire‐
jail 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/fire‐
jail 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 con‐
nect 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) fire‐
jail-users(5)
0.9.56 Sep 2018 FIREJAIL(1)
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I’m having some difficulty in getting mpd to background properly inside firejail. Using “mpd; sleep inf;” worked before, but it’s now responding with “mpd; sleep inf;: command not found”. What is the “official” way to get this working again? Thanks!
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It should work without “sleep inf”. Try “firejail mpd”.
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Nope, it just dies with “parent is shutting down, bye…”.
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I’ll try to fix it, you can track it here: https://github.com/netblue30/firejail/issues/320
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nosound option is breaking profiles.
I tried it in icedove, piding, firefox, and it breaks all of them. if i try to use a profile that has that option it just gives an error in that line. If I do it like “firejail –nosound firefox” however it works flawlessly. I am using 0.9.38
Any idea?
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nosound profile command is not available in 0.9.38. It will come in the next version.
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Also when I use the nosound option in one application, all the system gets sound deactivated 😦 is it normal??
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Yes, it disables ALSA and PulseAudio.
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I expected it to just prevent that specific application from using sound. It is very “anti-feature” this way, since to prevent one application from being exploited and used to spy, we lose sound in all the other apps. Any workaround?
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It disables the sound only for applications inside the sandbox. Unless you are running into this PulseAudio bug: https://firejail.wordpress.com/support/known-problems/
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When I installed this for use with Chrome it created a profile somewhere for Chrome so it starts with a loaded Chrome cache and some features enabled on Chrome extensions. So I clear the cache and change the extension settings every time I use it firejail google-chrome is how I start it. I’ve even removed it and reinstalled it but the profile is always the same. This is the latest version also. How do I go about deleting this? It’s acting like its in private mode which I thought was deprecated, Help!
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google-chrome configuration is persistent, and is stored in ~/.config/google-chrome directory. So, if you add a bookmark, next time you start chrome, your bookmark should be there. You can delete the configuration before starting chrome (rm -fr ~/.config/google-chrome). Your Download directory is also persistent.
If you really want to start every time with a default chrome config, you should run “firejail –private google-chrome”.
LikeLiked by 1 person
[quote]
This works for clicking on desktop environment icons, menus etc. Use
“firejail –tree” to verify the program is sandboxed.
[/quote]
Sadly it’s not working for most applications in Gnome3 in Debian Stretch. Probably because in the *.desktop files there is the full path written.
Do you know a workaround or you suggest to file a bugreport?
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I would suggest a bug report on https://github.com/netblue30/firejail
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Actually I found “firecfg –fix” in the meantime which is solving this issue. 🙂
Works fine now.
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Thanks!
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Hi. Many thanks for FireJail – it’s an amazing achievement.
Is there a way for FireJail to sandbox internet-facing programs, whose user-data & config files are NOT stored as conventional in /home, but instead are in separate partition /DATA [albeit symlinked back to /home] ? So far all my tests with combinations of –blacklist & –noblacklist in their launchers [for eg, Thunderbird & Firefox] have failed [& –whitelist can’t be used at all if i understand correctly, given their active directories are not in /home], in that either the programs can’t launch at all [because can’t access their config & data], or they launch but ALL other directories & files in /DATA are exposed to internet. Please?
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Sorry, there is no support in this moment for user directories located outside /home.
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That’s the unfortunate conclusion i’d come to, but given i am still not very skilled with FJ, i felt it best to ask you. Thank you.
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No problem.
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Pingback: Sandbox your applications with Firejail – Own your bits
Trying to use –private-home with Google Chrome default profile. I am trying to preserve the add-ons and plug-ins from my default Chrome profile. I’ve tried many iterations, including [firejail –private-home=~/.google-chrome/Default google-chrome-stable]
But Chrome just fails to load when I double-click on it in Firetools.
I have tried using many directory path options, but to no avail. Someone please help.
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Use –private only if you need a browser reseted to factory defaults, without any plugins and addons.
By default Firejail will allow you to use all Chrome addons and plugins. The only directories exposed in your home are Downloads and Chrome configuration files.
I would say just start it as “firejail chrome” and you should be ok. We do this for all browsers.
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netblue,
Thx for the info. Much appreciated. As I have been looking into optimizing the security features of Firejail and found out that –seccomp, –overlay and –overlay-tmpfs do not work with Chrome, I have managed to come up with the following (not sure if I’ve missed anything):
firejail –caps.drop=all –noroot –allow-private-blacklist –blacklist=/Home/ –read-only=~ google-chrome-stable
Chrome loads no problem and at least I’ve added some additional security features to further tighten the security of the sandbox.
I’m currently running Fedora v26 and as it relates to all the command-line parameters that add additional measures of security, It has taken a while to figure out what works with Chrome and what doesn’t.
That being said, and as others have mentioned previously, thank you for all your hard work (and anyone else who worked on Firejail/Firetools).
Cheers.
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Oops. I apologize for not mentioning this in my response above. My main purpose for implementing Firejail / Firetools is solely to improve upon the overall security of internet browsing sessions. I’m not testing software or writing code. This is just to help prevent virus / malware injection. Thanks again!
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Question: why don’t you use the default profile for Chrome distributed by firejail?
You’ll find it in /etc/firejail/google-*.,profile. We have profiles for all Chrome variants, including Chromium. All of them are basically the same, with very small differences. Some of features such as seccomp won’t work for Chrome browser because Chrom starts a second sandbox inside firejail sandbox.
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Indeed sir.
I found the /etc/firejail/google*.profile files and performed the steps (as you outlined in the profiles section here on the site) to save a new google-chrome-stable profile in my [/home/.config/firejail] directory and add the nonewprivs and noroot parameters. I also rem’ed out the caps.keep sys_chroot, sys_admin line and added caps.drop all. Now all I have to do is ‘firejail google-chrome-stable.’ I (again) apologize as I don’t really know if the chroot and admin capabilities are needed in Chrome for pure internet browsing. I conducted some on-line research on those capabilities, but couldn’t come up with anything definitive. As you can see, my working knowledge of Linux is not yet up to snuff.
NetBlue, again my sincere thanks for an awesome program.
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Pingback: Sandbox your applications with Firejail – Linux Now
Pingback: Using Firejail to sandbox applications in Linux – Excerpts of the Regginator
Hi
You’ve made a great tool here, and I’m grateful.
However, I am finding it hard to use. Partly that’s because I am learning about computer science as I go. I’m a noob.
But partly I am having trouble with the documentation. I find it dense, counter-intuititve and overwhelming. I’m not talking about the content (well, sometimes). Its the structure.
Case in point: I want to read up how to transfer a file out of sandbox into my host system’s Documents folder. This page has three places at least where “FILE TRANSFER” is located, and I have two options to find them: scrolling, a long way, or; crtl+F in my browser.
Why don’t those entries link to each other? Or any, between other parts of the page or site.
FILE TRANSFERS (your caps) is part of a large series of section titles, to which there is no link between them nor a table of contents.
There isn’t even an anchor so I can bookmark the spot once I’ve found it. [Add in extra time looking fruitlessly for browser extensions that might help].
Please remember that if you aren’t a commandline guru, you’ve committed to Linux years ago but you’re still figuring out what the hell namespaces are, you don’t have the tacit knowledge that might help you sail through this space. Its called tacit knowledge – enormously valuable, years in the making and possession of it is easily forgotten even by those who have it. I don’t have it.
You’re basically asking me to trawl through a page of gobbledygook (technical term) for something I don’t really understand, and even forget how to spell between ctrl+Fs.
Basic structure would give me so much more working memory to the substantive task (i.e. file transfer) rather than document navigation.
What kills me is that I remember having figured this out six months ago, but I’ve got to do it all over again… I’ve already lost a couple of hours that I don’t have.
This is a great tool. Can you make it more accessible? I am sure its not just me, but I’m pretty vocal (most else just slink away quietly and frustrated).
(To put money where my mouth is, I would have time in about 6 weeks to help. I’d have to learn a few things, but I’d be willing).
Constructively,
B.
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You are right, there is more work to do on the documentation side. And yes, it is way to technical in this moment.
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Furthermore, I just flat out can’t get the transfer to work.
First, I do this:
11:31:25 b:~ $ firemon –list
3799:b:/usr/bin/firejail /usr/bin/keepass2 /xxxxxxxxxxxxxxx
3821:b:/usr/bin/firejail /usr/bin/firefox
4632:b:/usr/bin/firejail /usr/bin/VirtualBox
13497:b:/usr/bin/firejail /usr/bin/google-chrome-stable
20129:b:firejail –private firefox –private-window –no-remote –no-first-run
22100:b:/usr/bin/firejail /usr/bin/pluma /home/b/xxxxxxxxxxxxxx
(edit – multiple x added by me)
I haven’t named my private firefox session (second from bottom) – I haven’t a clue as to how, and I got lost looking for instructions last time. I start the thing from a desktop launcher for banking, government websites, etc.
But, the instructions say PID can be used, so
11:33:36 b:~ $ sudo firejail –ls=20129 ~/Downloads
drwx—— b b 60 .
drwx—— b b 220 ..
-rw-rw-r– b b 13058 Target Document
So, I want ‘Target Document’.
11:34:07 b:~ $ firejail –get=20129 ~/Downloads/’Target Document’
Warning: cannot open source file /home/b/Downloads/Target Document, file not copied
“WTF…?” I mutter to myself. I recheck instructions. Nope…
The all-powerful sudo?
15:32:36 b:~ $ sudo firejail –get=20129 ~/Downloads/’Target Document’
Warning: cannot open source file /home/b/Downloads/Centrelink Statement, file not copied
Nope. It took me quite a while before I realised the permissions were probably at the heart of it. However, I can’t figure out how to get into that sandbox to modify permissions, and anyway – why should I, as a user on the host (and as sudo, no less), have to modify rights to copy a file I downloaded? I don’t understand the constraints, but seems weird. (If an attacker is issuing commands from the host terminal, the game is over already, surely?)
I tried a couple of other tacks
15:43:07 b:~ $ firejail –chmod=20129 777 ~/Downloads
Error: invalid –chmod=20129 command line option
15:44:49 b:~ $ $ firejail –whitelist=~/.mozilla –whitelist=~/Download firefox
$: command not found
and even tried the whole command listed in the –ls output as the `name`, but it didn’t work. Read the whole Firefox entry and couldn’t see the solution. Don’t know where to look, and note that a search engine brings up others with transfer problems, but I can’t devine enough to apply fixes to my situation.
I am absolutely stumped. Please help.
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I’m writing “./configure –prefix=/usr –enable-apparmor” into the terminal and it’s telling me the file or category can’t be found. Firejail is 100% installed. Am I doing something wrong? 😦
Linux Mint 19 XFCE.
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Maybe apparmor development package is not installed (sudo apt-get install libapparmor-dev)?
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