nsjail/README.md
2015-05-15 02:30:53 +02:00

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### WHAT IS IT?
NsJail is a Linux process isolation tool making use of the namespacing features, and seccomp-bpf filters of the Linux kernel
This is NOT an official Google product.
### WHAT KIND OF ISOLATION DOES IT PROVIDE?
1. Linux namespaces: UTS, MOUNT, PID, IPC, NET, USER (optional)
2. FS chroot-ing: chroot(), pivot_root()
3. Resource limits (CPU time, etc.)
4. Seccomp-bpf syscall filters
### WHAT USE-CASES DOES IT COVER?
#### Isolating networking daemons (inetd-style)
+ 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)
```
#### Isolating local processes (run it once, and exit)
```
$ ./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
/ $exit
$
```
#### Isolating local processes (and re-running them)
```
$ ./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.
/ $ exit
BusyBox v1.21.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.
/ $
```
### MORE INFO?
Type:
```
./nsjail --help'
```
the commandline options are reasonably well-documented