Restricted SFTP

This script implements SFTP restriction for Linux, based on user namespaces and bind mounts.

How to use?

To configure this, copy sftp-ssh-limit to ~/bin/sftp-ssh-limit:

mkdir -p ~/bin
curl -Lo ~/bin/sftp-ssh-limit https://raw.github.com/dgl/sftp-ssh-limit/refs/heads/main/sftp-ssh-limit
chmod 755 ~/bin/sftp-ssh-limit

Then set up an SSH key in ~/.ssh/authorized_keys with the following options (edit the line to add these before the key) where $HOME/Media, etc. are the directories to allow access to:

restrict,command="$HOME/bin/sftp-ssh-limit $HOME/Media $HOME/Pictures" ssh-ed25519...rest-of-key-all-on-one-line

You can also add -R before the list of directories to make the key only give read-only access.