Re: [Ironruby-core] Running IR in an isolated AppDomain

[Tomas Matousek]

You can write to standard output stream (just call Kernel#puts/print) and 
redirect it. See Runtime.IO object.
Or you can provide method Write on your Helper class.

Tomas

From: ironruby-core-boun...@rubyforge.org 
[mailto:ironruby-core-boun...@rubyforge.org] On Behalf Of Pascal Normandin
Sent: Saturday, October 03, 2009 10:06 PM
To: ironruby-core@rubyforge.org
Subject: Re: [Ironruby-core] Running IR in an isolated AppDomain

Hello Tomas,

Thanks you for your quick response.  The permission assert works very well!

Regarding the StringBuilder you are right the host created instance stays empty 
so I had to do a scope.GetVariable<StringBuilder>("output");
To get another copy of the StringBuilder.  I also felt this wasn't so neat but 
didn't know how to work around that.  The StringWriter approach is better but I 
always get a SEHException when using it.

Did you have any clue why?

Anyways I'll work more on that later.
Thanks again
Pascal

From: ironruby-core-boun...@rubyforge.org 
[mailto:ironruby-core-boun...@rubyforge.org] On Behalf Of Tomas Matousek
Sent: October-03-09 3:36 PM
To: ironruby-core@rubyforge.org
Subject: Re: [Ironruby-core] Running IR in an isolated AppDomain

Adding this:

FileIOPermission f = new FileIOPermission(PermissionState.Unrestricted);
f.AllLocalFiles = FileIOPermissionAccess.Read;
f.Assert();

to GetFileContent method should make the SecurityException go away.

However, passing data out of the sandbox via StringBuilder won't work. 
StringBuilder is serializable and not MarshalByRefObject (MBRO). The instance 
of StringBuilder created by the host is copied to the sandboxed app domain, 
where it is filled with data. The instance the host created will stay empty 
though. You need to use some MBRO, like StringWriter:

var sb = new StringBuilder();
var output = new StringWriter(sb);
...
ScriptSource source = 
rubyEngine.CreateScriptSourceFromString("output.write(helper.GetFileContent())");
...
Console.WriteLine(sb);

Tomas

From: ironruby-core-boun...@rubyforge.org 
[mailto:ironruby-core-boun...@rubyforge.org] On Behalf Of Pascal Normandin
Sent: Saturday, October 03, 2009 8:57 AM
To: ironruby-core@rubyforge.org
Subject: [Ironruby-core] Running IR in an isolated AppDomain

Hello,

I'm trying to add scripting capability to a wiki type web application with 
IronRuby.  I want to run IR in a low trust environment with only access to 
variables provided in the scope.  Those variables are helper objects that have 
access to local resources i.e. FS.

I'm able to create the AppDomain with restricted security, run IR in that 
AppDomain and use the helper objet from IR but I have a problem when invoking a 
method of the helper object that has access to the file system.

When I call my helper.GetFileContent() method (see below) from the IR AppDomain 
I receive the following exception

Request for the permission of type 
'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, 
Culture=neutral, PublicKeyToken=b77a5c561934e089' failed

At some point I thought that maybe the code is being executed from the IR 
AppDomain so I added a check on the AppDomain Name and it is executing in the 
Main AppDomain not the IR AppDomain.

Does anyone have an idea why it is behaving like that?
Is this the expected behaviour?
Or do you have any tip to help me troubleshoot and find the root of this?

Thank you;
Pascal Normandin


Here is my Helper class

    public class Helper : MarshalByRefObject {
        public string GetFileContent() {
            var appDomainName = AppDomain.CurrentDomain.FriendlyName;
            StreamReader rdr = File.OpenText("C:\\test\\test.txt");
            return rdr.ReadToEnd();
        }
    }


Here is How I create the ScriptRuntime in the AppDomain

        protected static ScriptRuntime CreateIronRubyRuntime()
        {
            // Setup the ruby engine in a Sandbox
            var rubySetup = Ruby.CreateRubySetup();

            rubySetup.Options["InterpretedMode"] = true;

            var runtimeSetup = new ScriptRuntimeSetup();
            runtimeSetup.LanguageSetups.Add(rubySetup);
            runtimeSetup.DebugMode = false;

            AppDomainSetup info = new AppDomainSetup();
            info.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory + 
"\\bin<file:///\\bin>";
            info.ApplicationName = "Wiki";

            PermissionSet ps1 = new PermissionSet(PermissionState.None);
            SecurityPermissionFlag flag = 
SecurityPermissionFlag.SkipVerification | SecurityPermissionFlag.Execution | 
SecurityPermissionFlag.ControlAppDomain;
            ps1.AddPermission(new SecurityPermission(flag));

            AppDomain newDomain = AppDomain.CreateDomain("IR", null, info, ps1);

            ScriptRuntime runtime = ScriptRuntime.CreateRemote(newDomain, 
runtimeSetup);

            return runtime;
        }


Here is how I execute the IR script

                var rubyEngine = Ruby.GetEngine(runtime);
                ScriptScope scope = runtime.CreateScope();

                StringBuilder sb = new StringBuilder();
                scope.SetVariable("output", sb);
                Helper helper = new Helper();
                scope.SetVariable("helper", helper);

                ScriptSource source = 
rubyEngine.CreateScriptSourceFromString("output.append(helper.GetFileContent())");
                source.Execute(scope);


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