# Purpose

We're going to be looking at how to create a server setup file that doesn't trigger any prompts that aren't user friendly. This setup file will contain another signed file that will launch a basic web server. The setup file will create the server file and a firewall rule for the server file. We will be building two files (`setup.go` and `server.go`) separately .

# The Server File

We're creating our web server file, building it and signing the application.

## Creating the Server File

Create a file named `server.go` and add the following:

```
//go:generate goversioninfo

package main

import (
	"flag"
	"log"
	"net/http"
)

func main() {

	port := flag.String("p", "8100", "port to serve on")
	directory := flag.String("d", ".", "the directory of static file to host")
	flag.Parse()

	http.Handle("/", http.FileServer(http.Dir(*directory)))

	log.Printf("Serving %s on HTTP port: %s\n", *directory, *port)
	log.Fatal(http.ListenAndServe(":"+*port, nil))
}
```

*Windows 10 will happily create server.go.txt if you don't turn off hidden file extensions and leave you wondering what's wrong with your Go install.*

First of all, you'll want to install Golang: https://golang.org/dl/
Then you'll want to install [goversioninfo](https://github.com/josephspurrier/goversioninfo) by running the following in a command prompt:

```
go get github.com/josephspurrier/goversioninfo/cmd/goversioninfo
```

This will allow us to set the name of the program, version, publisher name, etc.

```
# Add this to the top of your server go file.
//go:generate goversioninfo
# Then generate the configuration by running the following in a command prompt:
go generate
```

This will create a configuration file named `versioninfo.json` in the current directory. There are three things you will want to edit: 1. The version of the application, 2. The "publisher" or company name and 3. The product name.

![](versioninfo.png)

Near the top of the file, you will see `FileVersion` and `ProductVersion`.
You can set normal major, minor, patch and build versions for those values. The `FileVersion` is the version of the file and `ProductVersion` is the version of the application as a whole. You can most likely use the same version for both unless you're doing something unusual. You will set the same values again under `StringFileInfo`.

Next, you can set the "publisher name" by filling in the `CompanyName` value with the name of your organization.

Lastly, you can give your application a name, like "Go Web Server" under the `ProductName` value.

```
# Next, build your server app.
go build
```

You will want to sign your application, the next section will show you how.

## Signing the Setup File

### Getting a Code Signing Certificate

Be aware that you will likely need to create a Dun & Bradstreet listing to get an "organization" code-signing certificate: https://www.dandb.com/businessdirectory/products/ (this is free)

You can purchase a code-signing certificate here: https://cheapsslsecurity.com/comodo/codesigningcertificate.html The validation process will take 1-3 business days if your information is correct and you give them your D-U-N-S (Dun & Bradstreet) number. After you receive an email containing a link to the certificate, follow these directions in the **exact same** browser as the one you used to request the certificate : https://cheapsslsecurity.com/downloads.aspx?ispdf=true&iscs=true&filenm=Comodo_Code_Signing_Collection_Guide.pdf

### Signing the File

[Screenshot] Next, you will need to install Visual Studio. You can download Visual Studio here: https://visualstudio.microsoft.com/thank-you-downloading-visual-studio/?sku=Community&rel=16

In the install process, you will be greeted with this screen:

![](windowsdev.png)


Choose the "Universal Windows Platform Development" workload. After you have finished installing Visual Studio, open a "Developer Command Prompt for VS".

![](developerprompt.png)

 ```
 # Sign a file with your certificate.
 SignTool sign /t http://timestamp.comodoca.com /f codesigning.p12 /p <Password> file.exe
```

![](signfile.png)

You should see something like this:

![](donesigning.png)

# The Setup File

Now we're going to create the setup file that will create the firewall rule we need and "create" the server file for us.

## Firewall Rule

We are using Powershell to create the firewall rule, so we're going to install `go-powershell`.

```
# Install go-powershell
go get github.com/aquasecurity/go-powershell
```

Create a file named `setup.go` and include the following:

```
//go:generate goversioninfo -manifest=setup.exe.manifest
//Add a new firewall rule in Go.

package main

import (
	"os"
	"fmt"
	"log"
	"static" // Create fileb0x before this will work.
	"io/ioutil"
	ps "github.com/aquasecurity/go-powershell"
	"github.com/aquasecurity/go-powershell/backend"
)

func main() {

  // Grab files from virtual filesystem
	files, err := static.WalkDirs("", false)
	if err != nil {
		log.Fatal(err)
		log.Println("ALL FILES", files)
	}

  // here we'll read the file from the virtual file system
	b, err := static.ReadFile("server.exe")
	if err != nil {
		log.Fatal(err)
	}

  // Copy file from virtual filesystem to real filesystem
	err = ioutil.WriteFile("server.exe", b, 0644)
        if err != nil {
                fmt.Println("Error creating", "server.exe")
                fmt.Println(err)
                return
        }

	// choose a backend
	back := &backend.Local{}

	// start a local powershell process
	shell, err := ps.New(back)
	if err != nil {
		panic(err)
	}
	defer shell.Exit()

  // Set 'dir' to the current working directory.
	dir, err := os.Getwd()
	if err != nil {
		log.Fatal(err)
  }

	// Create the correct Poweshell rule with the working directory from 'dir'
	var cmd string = "-WindowStyle Hidden New-NetFirewallRule -DisplayName 'Name of Rule' -Direction Inbound -Program '" + dir + "\\server.exe' -Action Allow > NULL"
	// Run the command.
	stdout, stderr, err := shell.Execute(cmd)
		if err != nil {
			panic(err)
			fmt.Println(stderr)
		}
		fmt.Println(stdout)
}
```

Then create another file called `setup.exe.manifest` containing:

```
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
        <security>
            <requestedPrivileges>
                <requestedExecutionLevel level="requireAdministrator" uiAccess="false"/>
            </requestedPrivileges>
        </security>
    </trustInfo>
</assembly>
```

Rename `server.go` to `server.go_`

```
# Build the setup application.
go build -o setup.exe -ldflags "-s -w -H=windowsgui"
```

## Put Server File In Setup File

fileb0x