Ssh – rbash to limit user to its home directory closes sftp connection

centos6redhatrhel6sftpssh

Server: Red Hat Enterprise Linux Server release 6.5 (Santiago)

Using openssh-server to allow sftp connexions.

I'm trying to limit users to their own personal home directory.
So i modified /etc/passwd setting user "john" to use /bin/rbash instead of /bin/bash

john:502:503::/home/john:/bin/rbash

If i do that, john cannot connect via sftp: the connexion closes as soon as he logs in (sftp message is Connection closed) .
If i set the bash to /bin/bash instead, his connexion works fine, but then, john can travel all over the server file system using cd.

Can you explain what am I doing wrong in order to limit users connecting via sftp to their own directory?

Best Answer

rbash won't let you run commands with a leading /, if that's being attempted then it will simply exit.

Unless you're using the internal sftp-server, an attempt to exec /usr/libexec/sftp-server will fail.

Using Subsystem sftp internal-sftp in the sshd_config will fix that.

However, using rbash won't stop sftp from wandering around your filesystem, you probably want to chroot the users instead.

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