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windows-msi

README.rst

OpenVPN MSI Packaging

This folder contains scripts and binaries required to build and package OpenVPN 2.5+ and its dependencies to a set of platform-dependent MSI packages and an all-in-one EXE installer.

Requirements for building MSI packages

  1. WiX Toolset - tested with 3.11.1
  2. unzip.exe - tested with UnZip 6.00 of 20 April 2009, by Info-ZIP
  3. GNU tar.exe - tested with 1.30
  4. gzip.exe - tested with 1.9
  5. bzip2.exe - tested with 1.0.6, 6-Sept-2010

Note: unzip.exe, tar.exe, gzip.exe, and bzip2.exe must be in %PATH%.

Requirements for building OpenVPN and its dependencies

Building and packaging OpenVPN on Windows is a fairly complex process with lots of dependencies. If you're starting from scratch it is recommended to use the "msibuilder" VM in openvpn-vagrant.

If using Vagrant and Virtualbox is not an option you should be able to run the Vagrant provisioning scripts with suitable parameters on a fresh Windows 10-based system, though only Windows Server 2019 is tested.

In either case you will end up with a directory layout such as this:

  • openvpn-build
  • vcpkg (openssl etc.)
  • openvpn-gui
  • openvpn

Once the directories are laid out properly you need to add your code-signing PFX certificate into the certificate store:

Import-PfxCertificate -FilePath .\mycert.pfx -CertstoreLocation Cert:\Currentuser\My -Password (ConvertTo-SecureString -String "mypass" -Force -AsPlainText)

This command will print out the certificate thumbprint which you'll need later.

Now create a config file, build-and-package-env.ps1, next to build-and-package.ps1:

# Used by build scripts build-and-package.sh calls
$Env:VCPKG_ROOT = "${basedir}\vcpkg"
$Env:CMAKE = "C:\\Program Files\\CMake\\bin\\cmake.exe"
$Env:ManifestCertificateThumbprint = "cert thumbprint"
$Env:ManifestTimestampRFC3161Url = "http://timestamp.digicert.com"

Building and packaging

First step adjust version.m4. It is important to increment PRODUCT_VERSION and PRODUCT_VERSION_GUID on each release. MSI upgrading logic relies on this.

To build and package:

cd openvpn-build\windows-msi
.\build-and-package.ps1 -basedir ..\..

You can also define which OpenSSL vcpkg port to use:

.build-and-package.ps1 -basedir .... -openssl openssl .build-and-package.ps1 -basedir .... -openssl openssl3

If everything was set up correctly you should see three MSI packages in image subfolder, each signed and containing signed binaries.

build.wsf

The build.wsf is a simple Makefile type building tool used to generate MSI packages and EXE installers. It expects OpenVPN and its dependencies to be built and in the directory layout described above. It was developed to avoid Microsoft Visual Studio or GNU Make requirements. Refer to build.wsf for exact usage:

C:\openvpn-build\windows-msi>cscript build.wsf /?
Microsoft (R) Windows Script Host Version 5.812
Copyright (C) Microsoft Corporation. All rights reserved.

Packages OpenVPN for Windows.
Usage: build.wsf [<command>] [/a]

Options:

<command> : Command to execute (default: "all")
a         : Builds all targets even if output is newer than input

Commands:
all     Builds MSI packages and EXE installer
msi     Builds MSI packages only
exe     Builds EXE installer only
clean   Cleans intermediate and output files

The cscript build.wsf exe command does not build MSI packages. This is a safety feature to prevent accidental rebuild of already signed MSI files, should something accidentally touch any of the MSI package source files.

Digital signing

The build.wsf tool does not support digital signing of MSI and EXE files (yet). The sign-openvpn.bat and sign-msi.bat scripts handle that part.

The EXE installer does not ask for elevation. It extracts and launches appropriate MSI package unelevated. The UAC elevation is requested only later when MSI package actually starts the install process. Therefore, it is vital to digitally sign MSI packages.

When signing MSI packages, set a signature description (/d flag with signtool.exe utility). The msiexec.exe saves the MSI package under some random name and launches an elevated process to install it. When the signature on the MSI package contains no description, Windows displays the MSI filename instead on the UAC prompt. Now MSI having a random filename, the UAC prompt gets quite confusing. Therefore, we strongly encourage you to set a description in the MSI signature accurately describing the package content.

Digital signing of EXE installer is optional, but recommended to decrease the chance Windows SmartScreen will treat our EXE installer as malware on downloads.

Signing of tapctl.exe is mandatory as it requires elevation of privileges.