OpenBSD chroot(8)

short guide for using chroot

The chroot command changes its root directory to the supplied directory newroot and executes command, if supplied, or an interactive copy of the user’s shell.

goals:

• chroot ssh

## change to workdir
> cd /foo/bar

## get files from cdn of trust
> wget https://cdn.openbsd.org/pub/OpenBSD/6.6/amd64/base66.tgz
> wget https://cdn.openbsd.org/pub/OpenBSD/6.6/amd64/comp66.tgz
> wget https://cdn.openbsd.org/pub/OpenBSD/6.6/amd64/man66.tgz

## create chroot dir
> mkdir -p /foo/bar/ssh_chroot
> cd /foo/bar/ssh_chroot

## copy system resolv.conf to chroot dir
> cp /etc/resolv.conf /foo/bar/ssh_chroot/ssh/resolv.conf

## extract packs
> tar -xvzf /foo/bar/ssh_chroot/base67.tar
> tar -xvzf /foo/bar/ssh_chroot/comp67.tar
> tar -xvzf /foo/bar/ssh_chroot/man67.tar

## MAKEDEV
> cd dev
> ./MAKEDEV all

## chroot in /foo/bar
> chroot /foo/bar/ssh_chroot/ ldconfig /usr/lib /usr/local/lib
> chown root:wheel /foo/bar/ssh_chroot/
> chmod 755 /foo/bar/ssh_chroot/

## setup chroot user
> groupadd ssh-users
> useradd -g ssh-users -d /chroot/ssh/home/ssh-user -m ssh-user
> passwd ssh-users

## to activate append chroot in "/etc/ssh/sshd_conf"
> echo "ChrootDirectory /var/chroot/ssh" >> /etc/ssh/sshd_conf