jglim / gunbound-launcher

Replacement launcher for GunBound Thor's Hammer

Gunbound (Thor's Hammer) Launcher

This is a replacement for the game launcher that was used in GunBound Thor's Hammer (2006).

Quick Start

• Clone this repository and unarchive it somewhere safe
• In the TestClient folder, edit the server address and credentials in Launcher.ini
• Run Launcher.exe to start GunBound

Features

• Skip the GunBound installer. The registry keys are automatically set up if they are absent.
• No emulation of GunBound "Fetch" system required
• Essential settings can be provisioned via Launcher.ini (Server address, version)
• Minimal requirements: standalone binary Launcher.exe + configuration Launcher.ini, Requires .NET 4.0 which should be present on most modern systems
• Decent base to build your own launcher - credentials can be passed via command line
• Development features such as automatic DLL injection and the ability to launch GunBound with correct parameters while suspended (for debugging/removing GameGuard)

Why

The main GunBound.gme client is launched via the GunBound.exe launcher. However it is possible (and desirable) to skip the launcher as:

• GunBound's proprietary updating/patching "Fetch" system has to be emulated
• Existing fetch emulation does not validate the user's credentials anyway
• Credential checking is done again when the client connects to the world

As a side feature, removing the installer requirement also allows for quick "LAN party" style setups.

Usage

• Place Launcher.exe in the same folder as GunBound.gme
• Create a Launcher.ini file containing basic configuration
• Optional but recommended: Set up DxWnd to launch GunBound in windowed mode
• Run Launcher.exe to start GunBound. Credentials can be supplied via command line.

Launcher.ini is a text-based configuration file, where options are delimited with newlines \n. Windows line endings (\r\n) are automatically normalized. Keys and values are separated with =. These are the possible options:

• SERVER configures the registry so that the client connects to this address
• VERSION configures the registry so that the client runs normally. This value must match the XFS file version
• USERNAME and PASSWORD optionally provided here if setting it in the command line is inconvenient. The command line values take precedence, if available.
• CREATE_SUSPENDED if TRUE, the GunBound.gme process will be launched in a suspended state until the console window receives a keypress. Useful for attaching debuggers.
• INJECT_DLL if set, the DLL at the relative path will be injected via CreateRemoteThread
• EXIT_IMMEDIATELY if TRUE, the console does not close upon completion.

Here is an example configuration file for typical use cases:

USERNAME=testusername
PASSWORD=testpassword
SERVER=127.0.0.1
VERSION=280
EXIT_IMMEDIATELY=TRUE
CREATE_SUSPENDED=FALSE

How

The launcher sets up the registry to reflect a full GunBound installation. Key values such as IP, BuddyIP, Location and Version are also set based on the configuration file.

The game client is then launched directly:

• A 48-byte array is created, containing
  • ASCII-encoded username (bytes 0-15). Padded with 0
  • ASCII-encoded password (bytes 16-31) Padded with 0
  • The last set of 16 bytes remains safely as 0s. They appear to used be for a "invite-to-game" feature
• Data is then encrypted with AES-128 in ECB mode. The key is fixed in the client as FAEE85F24073D9161390197F6E562A67
• The output bytes are converted to an uppercase hex string. The result should be a 96-character credentials string
• GunBound.gme is started with the above value as its only command line parameter.
  • Conventionally when a process is started with arguments, its own path is also prepended e.g. "C:\Windows\system32\NOTEPAD.EXE" C:\some_file.txt.
  • Most implementations (batch files, subprocess.run, System.Diagnostics.Process.Start etc. do this by default)
  • The client exits if the executing path is included with the credentials string
  • Calling CreateProcess with the credentials string for the lpCommandLine parameter solves this issue

License

MIT

Game client and artwork assets belong to Softnyx