- Overview
- What forms of isolation does it provide
- Which use-cases are supported
- Examples of use
- Configuration file
- More info
- Launching in Docker
- Contact
This is NOT an official Google product.
NsJail is a process isolation tool for Linux. It utilizes Linux namespace subsystem, resource limits, and the seccomp-bpf syscall filters of the Linux kernel.
It can help you with (among other things):
- Isolating networking services (e.g. web, time, DNS), by isolating them from the rest of the OS
- Hosting computer security challenges (so-called CTFs)
- Containing invasive syscall-level OS fuzzers
Features:
- Offers three distinct operational modes. See this section for more info.
- Utilizes kafel seccomp-bpf configuration language for flexible syscall policy definitions.
- Uses expressive, ProtoBuf-based configuration file
- It's rock-solid.
- Linux namespaces: UTS (hostname), MOUNT (chroot), PID (separate PID tree), IPC, NET (separate networking context), USER, CGROUPS
- FS constraints: chroot(), pivot_root(), RO-remounting, custom
/procandtmpfsmount points - Resource limits (wall-time/CPU time limits, VM/mem address space limits, etc.)
- Programmable seccomp-bpf syscall filters (through the kafel language)
- Cloned and isolated Ethernet interfaces
- Cgroups for memory and PID utilization control
PS: You'll need to have a valid file-system tree in /chroot. If you don't have it, change /chroot to /
- Server:
$ ./nsjail -Ml --port 9000 --chroot /chroot/ --user 99999 --group 99999 -- /bin/sh -i
- Client:
$ nc 127.0.0.1 9000
/ $ ifconfig
/ $ ifconfig -a
lo Link encap:Local Loopback
LOOPBACK MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
/ $ ps wuax
PID USER COMMAND
1 99999 /bin/sh -i
3 99999 {busybox} ps wuax
/ $
PS: You'll need to have a valid file-system tree in /chroot. If you don't have it, change /chroot to /
$ sudo ./nsjail --user 9999 --group 9999 --macvlan_iface eth0 --chroot /chroot/ -Mo --macvlan_vs_ip 192.168.0.44 --macvlan_vs_nm 255.255.255.0 --macvlan_vs_gw 192.168.0.1 -- /bin/sh -i
/ $ id
uid=9999 gid=9999
/ $ ip addr sh
1: lo: mtu 65536 qdisc noqueue
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: vs: mtu 1500 qdisc noqueue
link/ether ca:a2:69:21:33:66 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.44/24 brd 192.168.0.255 scope global vs
valid_lft forever preferred_lft forever
inet6 fe80::c8a2:69ff:fe21:cd66/64 scope link
valid_lft forever preferred_lft forever
/ $ nc 217.146.165.209 80
GET / HTTP/1.0
HTTP/1.0 302 Found
Cache-Control: private
Content-Type: text/html; charset=UTF-8
Location: https://www.google.ch/?gfe_rd=cr&ei=cEzWVrG2CeTI8ge88ofwDA
Content-Length: 258
Date: Wed, 02 Mar 2016 02:14:08 GMT
...
...
/ $
PS: You'll need to have a valid file-system tree in /chroot. If you don't have it, change /chroot to /
$ ./nsjail -Mo --chroot /chroot/ --user 99999 --group 99999 -- /bin/sh -i
/ $ ifconfig -a
lo Link encap:Local Loopback
LOOPBACK MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
/ $ id
uid=99999 gid=99999
/ $ ps wuax
PID USER COMMAND
1 99999 /bin/sh -i
4 99999 {busybox} ps wuax
/ $exit
$
PS: You'll need to have a valid file-system tree in /chroot. If you don't have it, change /chroot to /
$ ./nsjail -Mr --chroot /chroot/ --user 99999 --group 99999 -- /bin/sh -i
BusyBox v1.21.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.
/ $ ps wuax
PID USER COMMAND
1 99999 /bin/sh -i
2 99999 {busybox} ps wuax
/ $ exit
BusyBox v1.21.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.
/ $ ps wuax
PID USER COMMAND
1 99999 /bin/sh -i
2 99999 {busybox} ps wuax
/ $
$ ./nsjail -Mo --user 0 --group 99999 -R /bin/ -R /lib -R /lib64/ -R /usr/ -R /sbin/ -T /dev -R /dev/urandom --keep_caps -- /bin/bash -i [2017-05-24T17:08:02+0200] Mode: STANDALONE_ONCE [2017-05-24T17:08:02+0200] Jail parameters: hostname:'NSJAIL', chroot:'(null)', process:'/bin/bash', bind:[::]:0, max_conns_per_ip:0, time_limit:0, personality:0, daemonize:false, clone_newnet:true, clone_newuser:true, clone_newns:true, clone_newpid:true, clone_newipc:true, clonew_newuts:true, clone_newcgroup:false, keep_caps:true, tmpfs_size:4194304, disable_no_new_privs:false, pivot_root_only:false [2017-05-24T17:08:02+0200] Mount point: src:'none' dst:'/' type:'tmpfs' flags:MS_RDONLY|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'none' dst:'/proc' type:'proc' flags:MS_RDONLY|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'/bin/' dst:'/bin/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'/lib' dst:'/lib' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'/lib64/' dst:'/lib64/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'/usr/' dst:'/usr/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'/sbin/' dst:'/sbin/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'none' dst:'/dev' type:'tmpfs' flags:0 options:'size=4194304' isDir:True [2017-05-24T17:08:02+0200] Mount point: src:'/dev/urandom' dst:'/dev/urandom' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:False [2017-05-24T17:08:02+0200] Uid map: inside_uid:0 outside_uid:69664 [2017-05-24T17:08:02+0200] Gid map: inside_gid:99999 outside_gid:5000 [2017-05-24T17:08:02+0200] Executing '/bin/bash' for '[STANDALONE_MODE]' bash: cannot set terminal process group (-1): Inappropriate ioctl for device bash: no job control in this shell bash-4.3# ls -l total 28 drwxr-xr-x 2 65534 65534 4096 May 15 14:04 bin drwxrwxrwt 2 0 99999 60 May 24 15:08 dev drwxr-xr-x 28 65534 65534 4096 May 15 14:10 lib drwxr-xr-x 2 65534 65534 4096 May 15 13:56 lib64 dr-xr-xr-x 391 65534 65534 0 May 24 15:08 proc drwxr-xr-x 2 65534 65534 12288 May 15 14:16 sbin drwxr-xr-x 17 65534 65534 4096 May 15 13:58 usr bash-4.3# id uid=0 gid=99999 groups=65534,99999 bash-4.3# exit exit [2017-05-24T17:08:05+0200] PID: 129839 exited with status: 0, (PIDs left: 0)
$ ./nsjail -Mo --user 99999 --group 99999 -R /lib/x86_64-linux-gnu/ -R /lib/x86_64-linux-gnu -R /lib64 -R /usr/bin/find -R /dev/urandom --keep_caps -- /usr/bin/find / | wc -l [2017-05-24T17:04:37+0200] Mode: STANDALONE_ONCE [2017-05-24T17:04:37+0200] Jail parameters: hostname:'NSJAIL', chroot:'(null)', process:'/usr/bin/find', bind:[::]:0, max_conns_per_ip:0, time_limit:0, personality:0, daemonize:false, clone_newnet:true, clone_newuser:true, clone_newns:true, clone_newpid:true, clone_newipc:true, clonew_newuts:true, clone_newcgroup:false, keep_caps:true, tmpfs_size:4194304, disable_no_new_privs:false, pivot_root_only:false [2017-05-24T17:04:37+0200] Mount point: src:'none' dst:'/' type:'tmpfs' flags:MS_RDONLY|0 options:'' isDir:True [2017-05-24T17:04:37+0200] Mount point: src:'none' dst:'/proc' type:'proc' flags:MS_RDONLY|0 options:'' isDir:True [2017-05-24T17:04:37+0200] Mount point: src:'/lib/x86_64-linux-gnu/' dst:'/lib/x86_64-linux-gnu/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:04:37+0200] Mount point: src:'/lib/x86_64-linux-gnu' dst:'/lib/x86_64-linux-gnu' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:04:37+0200] Mount point: src:'/lib64' dst:'/lib64' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:04:37+0200] Mount point: src:'/usr/bin/find' dst:'/usr/bin/find' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:False [2017-05-24T17:04:37+0200] Mount point: src:'/dev/urandom' dst:'/dev/urandom' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:False [2017-05-24T17:04:37+0200] Uid map: inside_uid:99999 outside_uid:69664 [2017-05-24T17:04:37+0200] Gid map: inside_gid:99999 outside_gid:5000 [2017-05-24T17:04:37+0200] Executing '/usr/bin/find' for '[STANDALONE_MODE]' /usr/bin/find: `/proc/tty/driver': Permission denied 2289 [2017-05-24T17:04:37+0200] PID: 129525 exited with status: 1, (PIDs left: 0)
$ tail -n1 /etc/subuid user:10000000:1 $ ./nsjail -R /lib -R /lib64/ -R /usr/lib -R /usr/bin/ -R /usr/sbin/ -R /bin/ -R /sbin/ -R /dev/null -U 0:10000000:1 -u 0 -R /tmp/ -T /tmp/ -- /bin/ls -l /usr/ [2017-05-24T17:12:31+0200] Mode: STANDALONE_ONCE [2017-05-24T17:12:31+0200] Jail parameters: hostname:'NSJAIL', chroot:'(null)', process:'/bin/ls', bind:[::]:0, max_conns_per_ip:0, time_limit:0, personality:0, daemonize:false, clone_newnet:true, clone_newuser:true, clone_newns:true, clone_newpid:true, clone_newipc:true, clonew_newuts:true, clone_newcgroup:false, keep_caps:false, tmpfs_size:4194304, disable_no_new_privs:false, pivot_root_only:false [2017-05-24T17:12:31+0200] Mount point: src:'none' dst:'/' type:'tmpfs' flags:MS_RDONLY|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'none' dst:'/proc' type:'proc' flags:MS_RDONLY|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/lib' dst:'/lib' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/lib64/' dst:'/lib64/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/usr/lib' dst:'/usr/lib' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/usr/bin/' dst:'/usr/bin/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/usr/sbin/' dst:'/usr/sbin/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/bin/' dst:'/bin/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/sbin/' dst:'/sbin/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'/dev/null' dst:'/dev/null' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:False [2017-05-24T17:12:31+0200] Mount point: src:'/tmp/' dst:'/tmp/' type:'' flags:MS_RDONLY|MS_BIND|MS_REC|0 options:'' isDir:True [2017-05-24T17:12:31+0200] Mount point: src:'none' dst:'/tmp/' type:'tmpfs' flags:0 options:'size=4194304' isDir:True [2017-05-24T17:12:31+0200] Uid map: inside_uid:0 outside_uid:69664 [2017-05-24T17:12:31+0200] Gid map: inside_gid:5000 outside_gid:5000 [2017-05-24T17:12:31+0200] Newuid mapping: inside_uid:'0' outside_uid:'10000000' count:'1' [2017-05-24T17:12:31+0200] Executing '/bin/ls' for '[STANDALONE_MODE]' total 120 drwxr-xr-x 5 65534 65534 77824 May 24 12:25 bin drwxr-xr-x 210 65534 65534 20480 May 22 16:11 lib drwxr-xr-x 4 65534 65534 20480 May 24 00:24 sbin [2017-05-24T17:12:31+0200] PID: 130841 exited with status: 0, (PIDs left: 0)
$ ./nsjail --chroot / --seccomp_string 'ALLOW { write, execve, brk, access, mmap, open, openat, newfstat, close, read, mprotect, arch_prctl, munmap, getuid, getgid, getpid, rt_sigaction, geteuid, getppid, getcwd, getegid, ioctl, fcntl, newstat, clone, wait4, rt_sigreturn, exit_group } DEFAULT KILL' -- /bin/sh -i
[2017-01-15T21:53:08+0100] Mode: STANDALONE_ONCE
[2017-01-15T21:53:08+0100] Jail parameters: hostname:'NSJAIL', chroot:'/', process:'/bin/sh', bind:[::]:0, max_conns_per_ip:0, uid:(ns:1000, global:1000), gid:(ns:1000, global:1000), time_limit:0, personality:0, daemonize:false, clone_newnet:true, clone_newuser:true, clone_newns:true, clone_newpid:true, clone_newipc:true, clonew_newuts:true, clone_newcgroup:false, keep_caps:false, tmpfs_size:4194304, disable_no_new_privs:false, pivot_root_only:false
[2017-01-15T21:53:08+0100] Mount point: src:'/' dst:'/' type:'' flags:0x5001 options:''
[2017-01-15T21:53:08+0100] Mount point: src:'(null)' dst:'/proc' type:'proc' flags:0x0 options:''
[2017-01-15T21:53:08+0100] PID: 18873 about to execute '/bin/sh' for [STANDALONE_MODE]
/bin/sh: 0: can't access tty; job control turned off
$ set
IFS='
'
OPTIND='1'
PATH='/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'
PPID='0'
PS1='$ '
PS2='> '
PS4='+ '
PWD='/'
$ id
Bad system call
$ exit
[2017-01-15T21:53:17+0100] PID: 18873 exited with status: 159, (PIDs left: 0)
You will also find all examples in the configs directory.
config.proto contains ProtoBuf schema for nsjail's configuration format.
You can examine an example config file in configs/bash-with-fake-geteuid.cfg.
Usage:
$ ./nsjail --config configs/bash-with-fake-geteuid.cfg
You can also override certain options with command-line options. Here, the executed binary (/bin/bash) is overriden with /usr/bin/id, yet options from configs/bash-with-fake-geteuid.cfg still apply
$ ./nsjail --config configs/bash-with-fake-geteuid.cfg -- /usr/bin/id ... [INSIDE-JAIL]: id uid=999999 gid=999998 euid=4294965959 groups=999998,65534 [INSIDE-JAIL]: exit [2017-05-27T18:45:40+0200] PID: 16579 exited with status: 0, (PIDs left: 0)
You might also want to try using configs/home-documents-with-xorg-no-net.cfg.
$ ./nsjail --config configs/home-documents-with-xorg-no-net.cfg -- /usr/bin/evince /user/Documents/doc.pdf $ ./nsjail --config configs/home-documents-with-xorg-no-net.cfg -- /usr/bin/geeqie /user/Documents/ $ ./nsjail --config configs/home-documents-with-xorg-no-net.cfg -- /usr/bin/gv /user/Documents/doc.pdf $ ./nsjail --config configs/home-documents-with-xorg-no-net.cfg -- /usr/bin/mupdf /user/Documents/doc.pdf
The configs/firefox-with-net.cfg config file will allow you to run firefox inside a sandboxed environment:
$ ./nsjail --config configs/firefox-with-net.cfg
A more complex setup, which utilizes virtualized (cloned) Ethernet interfaces (to separate it from the main network namespace), can be found in configs/firefox-with-cloned-net.cfg. Remember to change relevant UIDs and Ethernet interface names before use.
As using cloned Ethernet interfaces (MACVTAP) required root privileges, you'll have to run it under sudo:
$ sudo ./nsjail --config configs/firefox-with-cloned-net.cfg
The command-line options should be self-explanatory, while the proto-buf config options are described in config.proto
./nsjail --help
Usage: ./nsjail [options] -- path_to_command [args] Options: --help|-h Help plz.. --mode|-M VALUE Execution mode (default: 'o' [MODE_STANDALONE_ONCE]): l: Wait for connections on a TCP port (specified with --port) [MODE_LISTEN_TCP] o: Launch a single process on the console using clone/execve [MODE_STANDALONE_ONCE] e: Launch a single process on the console using execve [MODE_STANDALONE_EXECVE] r: Launch a single process on the console with clone/execve, keep doing it forever [MODE_STANDALONE_RERUN] --config|-C VALUE Configuration file in the config.proto ProtoBuf format (see configs/ directory for examples) --exec_file|-x VALUE File to exec (default: argv[0]) --execute_fd Use execveat() to execute a file-descriptor instead of executing the binary path. In such case argv[0]/exec_file denotes a file path before mount namespacing --chroot|-c VALUE Directory containing / of the jail (default: none) --no_pivotroot When creating a mount namespace, use mount(MS_MOVE) and chroot rather than pivot_root. Usefull when pivot_root is disallowed (e.g. initramfs). Note: escapable is some configuration --rw Mount chroot dir (/) R/W (default: R/O) --user|-u VALUE Username/uid of processes inside the jail (default: your current uid). You can also use inside_ns_uid:outside_ns_uid:count convention here. Can be specified multiple times --group|-g VALUE Groupname/gid of processes inside the jail (default: your current gid). You can also use inside_ns_gid:global_ns_gid:count convention here. Can be specified multiple times --hostname|-H VALUE UTS name (hostname) of the jail (default: 'NSJAIL') --cwd|-D VALUE Directory in the namespace the process will run (default: '/') --port|-p VALUE TCP port to bind to (enables MODE_LISTEN_TCP) (default: 0) --bindhost VALUE IP address to bind the port to (only in [MODE_LISTEN_TCP]), (default: '::') --max_conns VALUE Maximum number of connections across all IPs (only in [MODE_LISTEN_TCP]), (default: 0 (unlimited)) --max_conns_per_ip|-i VALUE Maximum number of connections per one IP (only in [MODE_LISTEN_TCP]), (default: 0 (unlimited)) --log|-l VALUE Log file (default: use log_fd) --log_fd|-L VALUE Log FD (default: 2) --time_limit|-t VALUE Maximum time that a jail can exist, in seconds (default: 600) --max_cpus VALUE Maximum number of CPUs a single jailed process can use (default: 0 'no limit') --daemon|-d Daemonize after start --verbose|-v Verbose output --quiet|-q Log warning and more important messages only --really_quiet|-Q Log fatal messages only --keep_env|-e Pass all environment variables to the child process (default: all envars are cleared) --env|-E VALUE Additional environment variable (can be used multiple times). If the envar doesn't contain '=' (e.g. just the 'DISPLAY' string), the current envar value will be used --keep_caps Don't drop any capabilities --cap VALUE Retain this capability, e.g. CAP_PTRACE (can be specified multiple times) --silent Redirect child process' fd:0/1/2 to /dev/null --stderr_to_null Redirect child process' fd:2 (STDERR_FILENO) to /dev/null --skip_setsid Don't call setsid(), allows for terminal signal handling in the sandboxed process. Dangerous --pass_fd VALUE Don't close this FD before executing the child process (can be specified multiple times), by default: 0/1/2 are kept open --disable_no_new_privs Don't set the prctl(NO_NEW_PRIVS, 1) (DANGEROUS) --rlimit_as VALUE RLIMIT_AS in MB, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 4096) --rlimit_core VALUE RLIMIT_CORE in MB, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 0) --rlimit_cpu VALUE RLIMIT_CPU, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 600) --rlimit_fsize VALUE RLIMIT_FSIZE in MB, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 1) --rlimit_nofile VALUE RLIMIT_NOFILE, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 32) --rlimit_nproc VALUE RLIMIT_NPROC, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 'soft') --rlimit_stack VALUE RLIMIT_STACK in MB, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 'soft') --rlimit_memlock VALUE RLIMIT_MEMLOCK in KB, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 'soft') --rlimit_rtprio VALUE RLIMIT_RTPRIO, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 'soft') --rlimit_msgqueue VALUE RLIMIT_MSGQUEUE in bytes, 'max' or 'hard' for the current hard limit, 'def' or 'soft' for the current soft limit, 'inf' for RLIM64_INFINITY (default: 'soft') --disable_rlimits Disable all rlimits, default to limits set by parent --persona_addr_compat_layout personality(ADDR_COMPAT_LAYOUT) --persona_mmap_page_zero personality(MMAP_PAGE_ZERO) --persona_read_implies_exec personality(READ_IMPLIES_EXEC) --persona_addr_limit_3gb personality(ADDR_LIMIT_3GB) --persona_addr_no_randomize personality(ADDR_NO_RANDOMIZE) --disable_clone_newnet|-N Don't use CLONE_NEWNET. Enable global networking inside the jail --disable_clone_newuser Don't use CLONE_NEWUSER. Requires euid==0 --disable_clone_newns Don't use CLONE_NEWNS --disable_clone_newpid Don't use CLONE_NEWPID --disable_clone_newipc Don't use CLONE_NEWIPC --disable_clone_newuts Don't use CLONE_NEWUTS --disable_clone_newcgroup Don't use CLONE_NEWCGROUP. Might be required for kernel versions < 4.6 --enable_clone_newtime Use CLONE_NEWTIME. Supported with kernel versions >= 5.3 --uid_mapping|-U VALUE Add a custom uid mapping of the form inside_uid:outside_uid:count. Setting this requires newuidmap (set-uid) to be present --gid_mapping|-G VALUE Add a custom gid mapping of the form inside_gid:outside_gid:count. Setting this requires newgidmap (set-uid) to be present --bindmount_ro|-R VALUE List of mountpoints to be mounted --bind (ro) inside the container. Can be specified multiple times. Supports 'source' syntax, or 'source:dest' --bindmount|-B VALUE List of mountpoints to be mounted --bind (rw) inside the container. Can be specified multiple times. Supports 'source' syntax, or 'source:dest' --tmpfsmount|-T VALUE List of mountpoints to be mounted as tmpfs (R/W) inside the container. Can be specified multiple times. Supports 'dest' syntax. Alternatively, use '-m none:dest:tmpfs:size=8388608' --mount|-m VALUE Arbitrary mount, format src:dst:fs_type:options --symlink|-s VALUE Symlink, format src:dst --disable_proc Disable mounting procfs in the jail --proc_path VALUE Path used to mount procfs (default: '/proc') --proc_rw Is procfs mounted as R/W (default: R/O) --seccomp_policy|-P VALUE Path to file containing seccomp-bpf policy (see kafel/) --seccomp_string VALUE String with kafel seccomp-bpf policy (see kafel/) --seccomp_log Use SECCOMP_FILTER_FLAG_LOG. Log all actions except SECCOMP_RET_ALLOW). Supported since kernel version 4.14 --nice_level VALUE Set jailed process niceness (-20 is highest -priority, 19 is lowest). By default, set to 19 --cgroup_mem_max VALUE Maximum number of bytes to use in the group (default: '0' - disabled) --cgroup_mem_memsw_max VALUE Maximum number of memory+swap bytes to use (default: '0' - disabled) --cgroup_mem_swap_max VALUE Maximum number of swap bytes to use (default: '-1' - disabled) --cgroup_mem_mount VALUE Location of memory cgroup FS (default: '/sys/fs/cgroup/memory') --cgroup_mem_parent VALUE Which pre-existing memory cgroup to use as a parent (default: 'NSJAIL') --cgroup_pids_max VALUE Maximum number of pids in a cgroup (default: '0' - disabled) --cgroup_pids_mount VALUE Location of pids cgroup FS (default: '/sys/fs/cgroup/pids') --cgroup_pids_parent VALUE Which pre-existing pids cgroup to use as a parent (default: 'NSJAIL') --cgroup_net_cls_classid VALUE Class identifier of network packets in the group (default: '0' - disabled) --cgroup_net_cls_mount VALUE Location of net_cls cgroup FS (default: '/sys/fs/cgroup/net_cls') --cgroup_net_cls_parent VALUE Which pre-existing net_cls cgroup to use as a parent (default: 'NSJAIL') --cgroup_cpu_ms_per_sec VALUE Number of milliseconds of CPU time per second that the process group can use (default: '0' - no limit) --cgroup_cpu_mount VALUE Location of cpu cgroup FS (default: '/sys/fs/cgroup/cpu') --cgroup_cpu_parent VALUE Which pre-existing cpu cgroup to use as a parent (default: 'NSJAIL') --cgroupv2_mount VALUE Location of cgroupv2 directory (default: '/sys/fs/cgroup') --use_cgroupv2 Use cgroup v2 --detect_cgroupv2 Use cgroupv2, if it is available. (Specify instead of use_cgroupv2) --iface_no_lo Don't bring the 'lo' interface up --iface_own VALUE Move this existing network interface into the new NET namespace. Can be specified multiple times --macvlan_iface|-I VALUE Interface which will be cloned (MACVLAN) and put inside the subprocess' namespace as 'vs' --macvlan_vs_ip VALUE IP of the 'vs' interface (e.g. "192.168.0.1") --macvlan_vs_nm VALUE Netmask of the 'vs' interface (e.g. "255.255.255.0") --macvlan_vs_gw VALUE Default GW for the 'vs' interface (e.g. "192.168.0.1") --macvlan_vs_ma VALUE MAC-address of the 'vs' interface (e.g. "ba:ad:ba:be:45:00") --macvlan_vs_mo VALUE Mode of the 'vs' interface. Can be either 'private', 'vepa', 'bridge' or 'passthru' (default: 'private') --disable_tsc Disable rdtsc and rdtscp instructions. WARNING: To make it effective, you also need to forbid `prctl(PR_SET_TSC, PR_TSC_ENABLE, ...)` in seccomp rules! (x86 and x86_64 only). Dynamic binaries produced by GCC seem to rely on RDTSC, but static ones should work. --forward_signals Forward fatal signals to the child process instead of always using SIGKILL. Examples: Wait on a port 31337 for connections, and run /bin/sh nsjail -Ml --port 31337 --chroot / -- /bin/sh -i Re-run echo command as a sub-process nsjail -Mr --chroot / -- /bin/echo "ABC" Run echo command once only, as a sub-process nsjail -Mo --chroot / -- /bin/echo "ABC" Execute echo command directly, without a supervising process nsjail -Me --chroot / --disable_proc -- /bin/echo "ABC"
To launch nsjail in a docker container clone the repository and build the docker image:
docker build -t nsjailcontainer .
This will build up an image containing nsjail and kafel.
From now you can either use it in another Dockerfile (FROM nsjailcontainer) or directly:
docker run --privileged --rm -it nsjailcontainer nsjail --user 99999 --group 99999 --disable_proc --chroot / --time_limit 30 /bin/bash
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