Prevent FTP users from moving directories

Question

I'm essentially trying to disable the mv command for FTP users on my CentOS server.

I was thinking of editing their .bash_profile file and using this:

alias mv=""

But that feels system breaking. Feels like there may be an actual, secure and better way to disable mv for FTP users.

All I want to allow for FTP users is PUT, GET and DELETE.

How do I restrict mv for FTP users properly?

Answer 1

Non-ftp way

Using file-system permissions.

You could make it so that directories and file are not in the same directories. Then you can remove write permission of the parent directories.

Explanation

In Unix, a file can not be added, removed, or renamed, if it is in a directory where the user does not have write permission. Therefore to prevent a file/directory from being moved, put it in a directory where there are no write permissions. Note the owner of the directory, can change the permissions.

You may need to re-arrange the directory structure, to do this.

Use the sticky-bit.

You can not remove a file (directory or anything else) from a directory with the sticky-bit set, unless you are the owner. This will also stop users removing/renaming files, unless they own them.