Table of Contents

VPN clients

The VPN management described in these pages is applicable until version KerOS 4.3.3. It is not applicable for firmware 5.x and upper.

The KerOS firmware comes with strongSwan and OpenVPN clients pre-installed. The credentials, however, need to be stored in a very specific way, described in this page.

Overview

The steps to make the VPN work are the following:

  1. Setup a PKI (Public Key Infrastructure) to be able to produce secrets.
  2. Generate secrets for the gateways to connect, in the PKCS#12 format.
  3. Write the main VPN configuration file (must match the server configuration).
  4. Write the ProvenCore specific configuration file.
  5. Cipher the ProvenCore specific configuration file.
  6. Cipher the P12 file.
  7. Initialize the TrustZone.
  8. Upload the ProvenCore specific ciphered configuration file to the TrustZone.
  9. Upload the ciphered P12 file to the TrustZone.
  10. Start the VPN client using the main VPN configuration file.

All the pnr_uploader commands return with a status. If the status is different from 0, this is a failure. Stop and ensure you followed all the steps before you continue.

General information

Wirnet™ i-series gateways embed the TrustZone security feature provided by ARM microprocessors. TrustZone technology is used to run a trusted boot and a trusted OS to create a Trusted Execution Environment.

The trusted OS is ProvenCore, from Prove&Run.

The firmware comes with two VPN clients: strongSwan (IPSec) and OpenVPN. These clients are modified to be able to read the secrets (passwords, keys, certificates, etc.) from that hardware-backed secure storage. This means that the sensitive data is encrypted and stored in a memory that cannot be read from the userland or even the kernel. The only way the data can be extracted is through the use of the embedded VPN clients, which are compiled using a dedicated library provided by ProvenCore.

Please ensure the server's version matches the client's version.

For example, if the embedded client's version is OpenVPN 2.3.14, please ensure the server uses a compatible version (if possible, the same).

You can check the version with: 

openvpn --version

Or: 

ipsec --version

The entire secret management on KerOS firmware is handled by ProvenCore for OpenVPN/strongSwan.

The TrustZone in the Wirnet iBTS is composed of five blocks, each having its dedicated purpose:

  • Block 0: ipsec.secrets config file
  • Block 2: OpenVPN config file
  • Block 10: Client certificate (OpenVPN)
  • Block 20: Client certificate (IPsec)

Step by step guide

Here are some examples that can be used to setup a whole VPN infrastructure:

  1. VPN - PKI management: VPN server setup
  2. VPN server configuration: VPN server configuration
  3. Setting up the VPN client: VPN client configuration
  4. Running the application / using a secret: VPN client startup