April 2015 – crossRT

Today I need to give my friend access to my server, so he can edit any files in that folder. My server is running OpenSSH and SFTP is enabled by default, actually I can create a new Linux user for him to access with SFTP. But I just want he accessing to the folder I gave him, so here I modify OpenSSH configuration to fit my need.

System details:

Ubuntu 14.04
Running OpenSSH

Steps:

Add a group called sftp.
```
sudo addgroup sftp
```
Add new user with default home path, assign to sftp group and disable shell access.
```
sudo useradd -m -g sftp -s /bin/false username
```
Give a new password for the user.
```
sudo passwd username
```
Change home directory’s user and group to root.
```
sudo chown root:root /home/username
```
Change home directory’s permission
```
sudo chmod 755 /home/username
```
Go into the folder
```
cd /home/username
```
Create a new folder named www.
```
sudo mkdir www
```
Change www folder’s user and group to username.
```
sudo chown username:username www
```
This step is the core. Edit to /etc/ssh/sshd_config with the editor you used to.
```
sudo nano /etc/ssh/sshd_config
```
Add following lines to the end of /etc/ssh/sshd_config.
```
Match group sftp
	ChrootDirectory %h
	X11Forwarding no
	AllowTcpForwarding no
	ForceCommand internal-sftp
	# PasswordAuthentication yes
```
Enable PasswordAuthentication by uncomment it if you enabled PubkeyAuthentication for other users in sshd_config.
Restart ssh service. Done.
```
sudo /etc/init.d/ssh restart
```

Month: April 2015

Setup SFTP for a user to access restricted folder only on Ubuntu 14.04