Adding Custom Basic Security to .NET Remoting

One of the problems I’ve seen in my ongoing search to understand Remoting is the issue of security when you publish a remotable object over a tcp channel. I spoke with Miguel and got some ideas from him and coded the following little remoting example which now simply publishes a “factory” which exposes a Login() method. If you give the right username and password it returns the SampleObject, otherwise it gives you null. Code below:

SampleClient.cs:

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace TestCode.Remoting
{
  public class SampleClient
  {
    public static void Main(string [] args)
    {
      ChannelServices.RegisterChannel(new TcpChannel());
      SampleFactory fac = (SampleFactory) Activator.GetObject(
        typeof(TestCode.Remoting.SampleFactory),
        "tcp://localhost:8080/SampleFactory" );

      // Use the object
      if( fac.Equals(null) )
      {
        Console.WriteLine( "Error: unable to locate server" );
      }
      else
      {
        Console.WriteLine( "Server found. We have a factory." );
        SampleObject obj = fac.Login( "test", "test" );
        if ( obj == null )
        {
          Console.WriteLine( "Login failed." );
        }
        else
        {
          Console.WriteLine( "Login successful." );
          Console.WriteLine( "count: {0}", obj.GetCount() );
        }
      }
    }
  }
}

SampleFactory.cs:

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace TestCode.Remoting
{
  public class SampleFactory : MarshalByRefObject
  {
    private SampleObject obj;
    public SampleFactory( SampleObject obj )
    {
      this.obj = obj;
    }
    public SampleObject Login( string username, string password )
    {
      if (username == "test" && password == "test")
      {
        Console.WriteLine("LOGIN GOOD");
        return obj;
      }
      else
      {
        Console.WriteLine("LOGIN BAD");
        return null;
      }
    }
    // Make object live forever
    public override Object InitializeLifetimeService()
    {
      return null;
    }
  }
}

SampleObject.cs:

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace TestCode.Remoting
{
  public class SampleObject : MarshalByRefObject
  {
    public int counter;
    public SampleObject()
    {
      counter = 0;
    }
    public int GetCount()
    {
      counter++;
      return counter;
    }
    // Make object live forever
    public override Object InitializeLifetimeService()
    {
      return null;
    }
  }
}

SampleServer.cs:

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace TestCode.Remoting
{
  public class SampleServer
  {
    public static void Main(string [] args)
    {
      // Create an instance of a channel
      TcpChannel channel = new TcpChannel(8080);
      ChannelServices.RegisterChannel(channel);
      // Create an instance of our object
      SampleObject obj = new SampleObject();
      SampleFactory fac = new SampleFactory( obj );
      // Publish our object
      RemotingServices.Marshal(fac, "SampleFactory");
      System.Console.WriteLine("Press the enter key to exit...");
      System.Console.ReadLine();
    }
  }
}

Makefile:

CSC=mcs --debug
default: all
SampleServer.exe: SampleServer.cs SampleObject.dll SampleFactory.dll
        $(CSC) /r:System.Runtime.Remoting /r:SampleObject.dll /r:SampleFactory.dll $<
SampleClient.exe: SampleClient.cs SampleObject.dll SampleFactory.dll
        $(CSC) /r:System.Runtime.Remoting /r:SampleObject.dll /r:SampleFactory.dll $<
SampleObject.dll: SampleObject.cs
        $(CSC) /r:System.Runtime.Remoting /target:library $<
SampleFactory.dll: SampleFactory.cs
        $(CSC) /r:System.Runtime.Remoting /r:SampleObject.dll /target:library $<
all: SampleObject.dll SampleServer.exe SampleClient.exe
clean:
        rm -f *.dll *.exe

Tags: Mono