Jail ssh user to home directory on Linux - LinuxConfig.org

LinuxConfig.org Articles
1

Jailing an SSH user to their home directory allows you (the administrator) to exercise a lot of control and security over the user accounts on a Linux system.

This is a companion discussion topic for the original entry at https://linuxconfig.org/jail-ssh-user-to-home-directory-on-linux
2

After configuring chroot environment I am getting this error for ping
OS: ubuntu 18.04
ping: socket: Permission denied, attempting raw socket…
ping: socket: Operation not permitted
ping: socket: Permission denied, attempting raw socket…
ping: socket: Operation not permitted

3

Hi Dhiraj_verma,

Welcome to our forums.

Are you trying to ping with the chrooted user? If so, the solution works as designed - the chrooted user will not have access to the rest of the system, functioning ping included.

4

Hello,

Can you help me with chroot ssh user on Ubuntu 20.04? Putty window closed immeadiatelly upon successful login.

After I checked auth.log there was the following error:
Dec 8 14:13:46 sd-xxxx sshd[540015]: Accepted password for demo from 110.x.x.173 port 2262 ssh2
Dec 8 14:13:46 sd-xxxx sshd[540015]: pam_unix(sshd:session): session opened for user demo by (uid=0)
Dec 8 14:13:46 sd-xxxx systemd-logind[545]: New session 216 of user demo.
Dec 8 14:13:46 sd-xxxx systemd: pam_unix(systemd-user:session): session opened for user demo by (uid=0)
Dec 8 14:13:47 sd-xxxx sshd[540058]: error: /dev/pts/4: No such file or directory

Using latest jailkit won’t work either, jailed user can access to ssh but not jailed.

5

Hi Lima_Simple,

Welcome to our forums.

What is your ChrootDirectory in your sshd_config file? You should mount pts under that directory’s dev subdirectory. So for example if you have this setting:

ChrootDirectory /secure/jail

You should mount like this (assuming dev directory exists):

$ sudo mount -o bind /dev/pts /secure/jail/dev/pts

6

I need to enable the use of other commands like git, vim, etc …

How can I do this?

7

Hi Yano,

Welcome to our forums.

Have you tried extending the list of commands that chroot.sh runs against at step 10 of the tutorial with the commands you require?

8

Several keys are not working, such as backspace. Tried stty sane but it is not working for me. Any suggestion? Thanks for tutorial.

9

At Step 10 I had a problem:
SSH login with user exampe threw an error and immediately closed the connection:

/bin/sh: No such file or directory

Solution:
in Step 4, bash was copied as a shell but Debian GNU/Linux 11 needs sh.
So simply copy sh to /var/chroot/bin

cp /bin/sh /var/chroot/bin

@Korbin maybe it’s a good idea to mention this in step 4.

Apart from that it’s an excellent article! Thank you.