Ein frohes neues Jahr! Jetzt will ich mal ein bisschen Leben in die Blog-Bude klopfen. Dieser Beitrag ist eher durch das aktuelle Semester als durch die zur Zeit viel behandelte “NSA-Problematik” motiviert. Kurz und knapp: Mit Powershell mal schnell nen SSL-Stream gebastelt. Hilft gegen neugierige Chefs, Geheimdienste, etc.

Server

#
# Server example of SSL
#

$port = 9105;
$cert = "D:\Hier\gehts\zum\Cert\Testserver.pfx";
$pk_pass = "strenggeheim";

# Run the server
function RunServer(){    

    # Listen
    $listener = New-Object System.Net.Sockets.TcpListener($port);    
    $listener.Start();

    Write-Host "Listening on port $port";
    
    # Waiting for client 
    $client = $listener.AcceptTcpClient();        
    ProcessClient($client);
    
    # Stop server
    $listener.Stop(); 
}

# Create a ssl stream
function GetSslStream($client){
    $serverCertificate =  New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($cert, $pk_pass);
    $sslStream = New-Object System.Net.Security.SslStream($client.GetStream(), $false)
    $sslStream.AuthenticateAsServer($serverCertificate, $false, [System.Security.Authentication.SslProtocols]::Tls, $true);
    return $sslStream;
}

# Process connected client
function ProcessClient($client){    
    $sslStream = GetSslStream($client);
    $streamReader = New-Object System.IO.StreamReader($sslStream);
    $streamWriter = New-Object System.IO.StreamWriter($sslStream);    
    $line = "";
    
    # Sending "welcome"
    $streamWriter.WriteLine("Welcome to the SSL server!");
    $streamWriter.Flush();

    # kick out
    while($line -ne "exit"){            
        $line = $streamReader.ReadLine();        
        Write-Host $line;
        $streamWriter.WriteLine($line);        
        $streamWriter.Flush();
    }
}

RunServer;

Client

# 
# Connect the Sample Server using SSL
#

function ConnectClient(){
    
    # Connect
    $client = New-Object System.Net.Sockets.TcpClient("192.168.30.31", 9105);
    
    # Make it possible to use self-signed certification
    $validate = { $true };
    
    # Authenticate    
    $sslStream = New-Object System.Net.Security.SslStream($client.GetStream(), $false, $validate, $null);        
    $sslStream.AuthenticateAsClient("localhost");

    # print welcome
    $streamReader = New-Object System.IO.StreamReader($sslStream);
    Write-Host $streamReader.ReadLine();

    # Hello ...
    $streamWriter = New-Object System.IO.StreamWriter($sslStream);
    $streamWriter.WriteLine("Hello World!");
    $streamWriter.Flush();

    # ... and bye
    $streamWriter.WriteLine("exit");
    $streamWriter.Flush();
}

ConnectClient;