Ubuntu 14.04. Как ограничить перемещение пользователя ssh его домашним каталогом, а лучше не домашним а другим?
В sshd_config:Match User someuser
    ChrootDirectory /some/directory
Так же, в "man sshd_config" сказано: The ChrootDirectory must contain the necessary files and  directories  to  support the user's session.  For an interactive session this requires at least a shell, typically sh(1), and  basic /dev  nodes  such  as  null(4),  zero(4),  stdin(4),  stdout(4), stderr(4), and tty(4) devices.  For file transfer sessions using ``sftp'', no additional configuration of the environment is necessary if the in-process sftp server is  used,  though  sessions which  use logging may require /dev/log inside the chroot directory on some operating systems (see sftp-server(8) for details).
ssh chroot вас спасет.