How to create a FTP user with specific /dir/ access only on a Centos / linux installation

Question

So I'm on a VPS - CentOS Linux installation. I have vsFTPd on the server. I currently have SFTP access to the server via my root user, but am now trying to create a new user with FTP access to a specific directory only on the server, I've done the following:

1. mkdir /var/www/mydomain.com
2. mkdir /var/www/mydomain.com/html
3. useradd <-username>
4. passwd <-username>
5. chown –R <-username> /var/www/mydomain.com
5. groupadd <-groupname>
6. gpasswd -a <-username> <-groupname>
7. chgrp -R <-groupname> /var/www/mydomain.com
8. chmod -R g+rw /var/www/mydomain.com

What I'm struggling to do is to create the user to ONLY have access to /var/www/mydomain.com - I observed that the user correctly logs into the right folder, however the user can then browse "back" to other directories. I want the user to stick in the specific folder and not being able to "browse" back.

Any ideas?

I've found different articles on chrooting, but simply haven't figured it out to use it in the steps included above.

Answer 1

It's quite simple.

You have to add the following option on the vsftpd.conf file

chroot_local_user=YES

The documentation inside the configuration file is self-explanatory:

# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().

This means, that the user will just have access on the folder you configured as HOME of the user.Below, i have an example of a user passwd entry:

upload_ftp:x:1001:1001::/var/www/sites/:/bin/bash

Set the home directory of the user with the following command

usermod -d /var/www/my.domain.example/ exampleuser

Note: In my example, this user is also a valid user for some scheduled tasks inside Linux. If you don't have this need, please change the shell of the user to /sbin/nologin instead of bash.

Answer 2

After you've changed your config to include chroot_local_user=YES

You could change the user's shell to /usr/sbin/nologin so that if the password leaks you will have mitigated some risk (set the home directory too). The shell needs to be listed in /etc/shells as well or authentication will fail.

usermod -d /var/www/my.domain.example -s /usr/sbin/nologin exampleuser

-d, --home HOME_DIR The user’s new login directory. If the -m option is given the contents of the current home directory will be moved to the new home directory, which is created if it does not already exist.

-s, --shell SHELL The name of the user’s new login shell. Setting this field to blank causes the system to select the default login shell.

https://security.appspot.com/vsftpd/FAQ.txt

Answer 3

Here are steps to setup a user and allow the user access only via FTP (i.e. no SSH) and also limit access to a specific (user home) directory on proftpd:

1. Add new user: adduser newusername

2. Set password: passwd newusername

3. Modify user home directory from default to a new folder:

   usermod -d /target/directory username

4. Edit shells file: vi /etc/shells and add /dev/null at the end

5. Modify newusername entry in the passwd file: vi /etc/passwd to add /./ before the newusername so that the entry looks like this:

   newusername:x:502:502::/home/ftp/./newusernamehomedirectory/:/dev/null

   Details for steps 4 & 5 here:

6. Edit /etc/proftpd/proftpd.conf file and uncomment the line DefaultRoot ~

Answer 4

Run this command:

useradd -d ftp_user:chown 711 /etc/init.d/

Answer 5

Set the root folder permissions to 711 with your root account.