cpyvpn

cpyvpn is pure python implementation of the Checkpoint VPN client.

Features

• SSL Network eXtender based.
• 'Legacy' and new login mode with realm select and Multi Factor authorization.
• Certificate-based login, certificate enrollment and renewal.
• Mobile Access Portal authorization and Native Applications support.
• Intermediary CAs certificates fetch when gateway certificate does not contain full trust chain.
• Privileged and root-less VNA (Virtual Network Adapter) modes of operation.

Description of the executables

cpyvpn contains three scripts: cp_client, cp_server and cpga.pyz.

• cp_client is similar to the snx utility from CheckPoint: it establishes VPN between client host and private network behind gateway.

• cpga.pyz performs Mobile Access Portal (MAP) authorization to get session cookie, used during MAP SNX tunnel setup.

Note 1: Separate cpga.pyz is not currently available. Refer to the cpga.pyz build instructions to make one if needed. cpga script is still installed alongside cp_client.

Note 2: Test server script and data files are no longer included in the release wheel. Download the source distribution to run the test server.

All scripts support a number of different options. Invoke them with -h flag to see full help.

Cached CA certs is stored in the cache.pem, located in:

• ~/.cache/cpyvpn - on Unux and the likes
• ~/Library/Caches/cpyvpn - on Mac OS X
• C:\Users<username>\AppData\Local\cpyvpn\cpyvpn\Cache

Installation

Dependencies for the current version of the scripts is Python 3.7+ and:

• TUN/TAP device driver for NM or vpnc-script (see below) modes
• UTUN device driver on macOS (available starting from 10.6.8 version) with vpnc-script
• NetworkManager (NM) for cp_server and cp_client in default mode (without -s or -S)

Main package wheel is self-contained and all scripts can be run from the directory containing the wheel like this:

env PYTHONPATH=cpyvpn-<version>-py3-none-any.whl python -m cpyvpn.client std.server.org

env PYTHONPATH=cpyvpn-<version>-py3-none-any.whl python -m cpyvpn.ma ma.server.org

Or from the source folder:

python -m cpyvpn.client std.server.org

python -m cpyvpn.srv.server localhost:4433

A regular pip install is supported as well. In latter case script names are cp_client and cpga.

cpga.pyz - a self-contained version of cpyvpn.ma - does not require installation also and intended to be used as a standalone program: cpga.pyz ma.server.org or be invoked from e.g. openconnect:

VNA modes

Network Manager (linux)

By default cp_client and cp_server rely on the NM to do tun device configuration and to run without root privileges. Please note, that the user running cp_client/cp_server must be in plugdev group and be logged in locally (not ssh!) for the NM to allow required network setup.

vpnc script (linux/macOS)

Download current version from here, use with -s command line switch. Requires superuser privileges to initialize and configure VNA device.

vpn proxy (linux/macOS)

cp_client can use ocproxy or tunsocks, originally written for the openconnect. Such configuration works entirely in the user mode.

vpnns (linux)

Part of ocproxy package to use with 'hard-to-proxy' protocols and applications. Refer to the ocproxy documentation for more info. Works in the user mode just like aforementioned proxy programs.

More usage examples

• Standard (TRAC) login with user name and password using default VNA:

  cp_client -m l -u testuser vpn.example.org

• TRAC login with realm and predefined user name:

  cp_client --realm vpn -u testuser vpn.example.org

• TRAC login with the predefined user name, run in the background after user authication, redirect output to cp.log and save background process pid to the cp.pid file:

  cp_client --daemon --logfile=./cp.log --pidfile=./cp.pid -u testuser vpn.example.org

• TRAC login with predefined user name and password from external program:

  cp_client -u user --passwd-script 'kwallet-query kdewallet' vpn.example.org

• TRAC login with certificate as a first factor:

  cp_client -c cert.pem vpn.example.org

• MAP login:

  cp_client https://vpn.example.org/sslpvn/

• MAP login with certificate:

  cp_client -c cert.pem https://vpn.example.org/sslpvn/

• MAP login with cookies from browser:

  echo 'CPCVPN_SESSION_ID=...; CPCVPN_BASE_HOST=...'| cp_client --cookies-on-stdin ... https://vpn.example.org/sslpvn/Portal/Main

  Session cookie can be extracted using browser extension Export Cookies, cookie-editor, Get cookies.txt, etc. Builtin browser development tools can to of use here also.

• MAP logout from browser session:

  echo 'CPCVPN_SESSION_ID=...; CPCVPN_BASE_HOST=...'| cpga --so --cookies-on-stdin https://vpn.example.org/sslpvn/Portal/Main

• User mode proxy with ssh and rdp forwarding:

  cp_client -S 'ocproxy -L 2222:<host_ip1>:22 -L 3389:<host_ip2>:3389' vpn.example.org

  After successful login you may run commands like: ssh -p2222 localhost or xfreerdp /v:localhost

• vpnc-based VNA configuration(with sudo or root shell):

  sudo cp_client -s '<vpnc_script_filename>' -u testuser vpn.example.org

• Certificate enrollment:

  cp_client --enroll -c ./cert.p12 vpn.example.org

  After successfull certificate fetch cp_client will try to convert from p12 to pem using openssl. If conversion fails for some reason user should do it manually.

• Certificate renewal:

  cp_client --rc new_cert.p12 -c ./cert.p12 vpn.example.org

  Conversion notes applies here likewise.

Performance

Python incurs extra overhead and the maximum bitrate will be 2-3 times lower than the bitrate achievable with the native client or openconnect. However it will only be noticable when the link speed is >100MB/s.

Known Issues

• Early R81 gateway versions were 'enhanced' in a way affecting user experience. One of the enhancements (or a bug) prevents multiple tunnel initializations from the same Web Portal session. Any client doing second connection attempt just hangs. In this case either logout manually after each cp_client run, use cpga logout or add --force_logout to perform automatic signout after tunnel shutdown to workaround this issue.

• Internal DNS will need additional setup with the vpnc script. Interface priority/ordering must be adjusted manually. E.g. 'interface_order="snx* lo* en*"' in resolvconf.conf file for resolvconf tool.

Source installation

Download sources using git or as an archive (and unzip if necessary).

Run a command in the source directory:

python -m pip install [-e] . (Preferred way)

or

python setup.py install|develop

Add --user flag if needed.

Build cpga.pyz from source

Run in the top source folder: python setup.py build_cpga

The path to the generated file will be: dist/cpga.pyz

License

Copyright © 2020-2022 Nikolay A. Krylov All rights reserved.

The cpyvpn is a free software package, distributed under GPLv3 license. See the file LICENSE for more details.