VPN

The Software Heritage server and the VMs running on it are severely firewalled. To get onto their network unrestricted, a VPN based on OpenVPN is available.

The setup is client-server, with per-client certificates.

OpenVPN client configuration

Raw OpenVPN

Sample configuration file, e.g., /etc/openvpn/swh.conf:

remote vpn.softwareheritage.org
ns-cert-type server 
comp-lzo 
nobind
dev tun
proto udp 
port 1194 
log /var/log/openvpn.log
up-restart 
persist-key 
persist-tun 
client 
ca /etc/openvpn/keys/softwareheritage-ca.crt
cert /etc/openvpn/keys/softwareheritage.crt
key /etc/openvpn/keys/softwareheritage.key
user nobody
group nogroup

# If you are using resolvconf, add this:
# Make sure you add louvre to /etc/hosts to avoid issues in using the vpn-provided DNS server.
script-security 2
up /etc/openvpn/update-resolv-conf
down /etc/openvpn/update-resolv-conf

# If you want the connection to persist when your network fails, add this:
ping-restart 10

In addition to the above configuration file, you will need to install the following 3 files under /etc/openvpn/keys (matching the paths within the sample above):

• softwareheritage-ca.crt: public certificate for the Software Heritage certification authority (CA)
• softwareheritage.crt: public, client-specific (certificate signed by the admin, see below)
• softwareheritage.key: private, client-specific key (generated by the user, see below)

Activate the openvpn server

as root, run

  systemctl enable openvpn@swh.service
  systemctl start openvpn@swh.service
  systemctl status openvpn@swh.service

Note: Internally, the `swh` must match the /etc/openvpn/swh.conf filename.

Excerpt of a successful start:

 root@machine:~# systemctl status openvpn@swh.service
 openvpn@swh.service - OpenVPN connection to swh
  Loaded: loaded (/lib/systemd/system/openvpn@.service; indirect; vendor preset: enabled)
  Active: active (running) since Thu 2020-12-17 19:03:29 IST; 22min ago
    Docs: man:openvpn(8)
          https://community.openvpn.net/openvpn/wiki/Openvpn24ManPage
          https://community.openvpn.net/openvpn/wiki/HOWTO
Main PID: 12302 (openvpn)
  Status: "Initialization Sequence Completed"
   Tasks: 1 (limit: 4915)
  CGroup: /system.slice/system-openvpn.slice/openvpn@swh.service
          └─12302 /usr/sbin/openvpn --daemon ovpn-swh --status /run/openvpn/swh.status 10 --cd /etc/openvpn --script-security 2 --config /etc/openvpn/swh.conf --writepid /run/openvpn/swh.pid

Dec 17 19:03:29 machine systemd[1]: Starting OpenVPN connection to swh... Dec 17 19:03:29 machine systemd[1]: Started OpenVPN connection to swh.

Network Manager GUI

You need network-manager-openvpn and network-manager-openvpn-gnome for the configuration gui.

Obtaining a client certificate

For users

Generate a keypair (key + certificate signing request) using the following command:

openssl req -new -newkey rsa:2048 -nodes -keyout openvpn.key -out openvpn.csr -subj "/CN=<your username>"

Please replace <your username> with something that uniquely identifies the certificate.

Make sure openvpn.key is stored in a safe place (it's your private key, which will allow anyone to connect to the VPN).

Provide the CSR file to a sysadmin through a reasonably authenticated medium.

For admins

• On the firewall (192.168.50.1), go to the System / Trust / Certificates page
• click on the add button on the upper right

• On the Method list, choose "Sign a certificate Signing Request"

Fetch the CSR file provided by the user, for instance with scp USERNAME.csr louvre:

• Enter the user name on the descriptive name
• Select "OpenVPN Software Heritage (louvre)" as Certificate Authority
• Enter the duration, usually 10 years
• Paste the csr
• Validate

• check the details of the csr and validate

Revoking a client certificate

On the firewall (master) [1]:

• go to the [System / Trust / Revocation] page
• edit the "OpenVPN certificate revocation list" CRL

• go to the bottom of the page

• select the certificate to revoke
• Add

The counter of revoked certificate should be increased by one on for the OpenVPN CSR on the CSR list