# Running IR in an isolated AppDomain

**URL:** <https://www.ruby-forum.com/t/running-ir-in-an-isolated-appdomain/176638>\
**Category:** IronRuby\
**Created:** [October 3, 2009, 6:58pm UTC](https://www.ruby-forum.com/t/running-ir-in-an-isolated-appdomain/176638 "2009-10-03T18:58:16Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Pascal\_Normandin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/f475e1/32.png) [@Pascal\_Normandin](https://www.ruby-forum.com/u/Pascal_Normandin)\
**Post date:** [October 3, 2009, 6:58pm UTC](https://www.ruby-forum.com/t/running-ir-in-an-isolated-appdomain/176638/1 "2009-10-03T18:58:16Z")

</div>

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”;

```
        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);
```

---

<div class="post-metadata">

**Author:** ![Pascal\_Normandin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/f475e1/32.png) [@Pascal\_Normandin](https://www.ruby-forum.com/u/Pascal_Normandin)\
**Post date:** [October 3, 2009, 10:02pm UTC](https://www.ruby-forum.com/t/running-ir-in-an-isolated-appdomain/176638/2 "2009-10-03T22:02:38Z")

</div>

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: removed\_email\_address@domain.invalid  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Pascal  
Normandin  
Sent: Saturday, October 03, 2009 8:57 AM  
To: removed\_email\_address@domain.invalid  
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”;

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);

---

<div class="post-metadata">

**Author:** ![Pascal\_Normandin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/f475e1/32.png) [@Pascal\_Normandin](https://www.ruby-forum.com/u/Pascal_Normandin)\
**Post date:** [October 4, 2009, 7:10am UTC](https://www.ruby-forum.com/t/running-ir-in-an-isolated-appdomain/176638/3 "2009-10-04T07:10:30Z")

</div>

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(“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: removed\_email\_address@domain.invalid  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Tomas M.  
Sent: October-03-09 3:36 PM  
To: removed\_email\_address@domain.invalid  
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: removed\_email\_address@domain.invalid  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Pascal  
Normandin  
Sent: Saturday, October 03, 2009 8:57 AM  
To: removed\_email\_address@domain.invalid  
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);

```

---

<div class="post-metadata">

**Author:** ![Pascal\_Normandin](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/f475e1/32.png) [@Pascal\_Normandin](https://www.ruby-forum.com/u/Pascal_Normandin)\
**Post date:** [October 4, 2009, 8:30am UTC](https://www.ruby-forum.com/t/running-ir-in-an-isolated-appdomain/176638/4 "2009-10-04T08:30:39Z")

</div>

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

Tomas

From: removed\_email\_address@domain.invalid  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Pascal  
Normandin  
Sent: Saturday, October 03, 2009 10:06 PM  
To: removed\_email\_address@domain.invalid  
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(“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: removed\_email\_address@domain.invalid  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Tomas M.  
Sent: October-03-09 3:36 PM  
To: removed\_email\_address@domain.invalid  
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: removed\_email\_address@domain.invalid  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Pascal  
Normandin  
Sent: Saturday, October 03, 2009 8:57 AM  
To: removed\_email\_address@domain.invalid  
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”;

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);