Problems securing a component with LinkDemand.

[Petri J. Riipinen]

Hi folks,

I have the following situation:

- MyApplication.e xe is an WinForms-application that is signed with
"AppKey.snk ".
- MyControls.dll contains a MyComponent-class that I want to drop on a form
on the application. This assembly is signed with "ControlsKey.sn k"

I don't want anyone else using the control from MyControl.dll except
MyApplication.e xe, or any other application that would be signed with
"AppKey.snk ".

Browsing through the newsgroups via Google, I got the understanding
StrongNameIdent ityPermission with LinkDemand-action would be the way to go,
as that would require the immediate caller of MyComponent-class (which
should be MyApplication) to be signed with a specfic key-pair. So I have
done the declarative security on MyComponent-class like this:

<StrongNameIden tityPermission( SecurityAction. LinkDemand, _
PublicKey:="002 400000480000094 000000060200000 024000052534131 000400" & _
"0001000100bfb4 cb9b5d7c4d678b8 35fafd56d6bdba7 4774d3c5f6" & _
"38f2261885275f abefd93be9f7c5a 5f4c7e180231318 5263eff0f5" & _
"23f4f6e54e4fd3 8375ab64257fe48 4609d237a650874 6faa9f929a" & _
"03eac98c629795 5e8649bf3a660c2 f1a2117001699d4 2ca00b572a" & _
"d69a005de41412 73bbc93fbe670e1 01be349076074fa cc5fb6")> _
Public Class MyComponent
Inherits System.Componen tModel.Componen t
.....etc...

The Hex-string contains the public key from AppKey.snk.

Here is the problem: When I run my MyApplication I always get an exception
on the "InitializeComp onent"-call on my application, i.e. in the designer
generated constructor:

Public Sub New()
MyBase.New()
Try

'This call is required by the Windows Form Designer.
InitializeCompo nent() <-- Debugger stops here, if "break on
exception" is on.

'Add any initialization after the InitializeCompo nent() call
Catch ex As Exception
Windows.Forms.M essageBox.Show( ex.Message, "Exception" )
End Try

End Sub

The exception message is:
"Request for the permission of type
System.Security .Permissions.St rongNameIdentit yPermission, mscorlib,
Version=1.0.500 0.0, Culture=neutral , PublicKeyToken= b77a5c561934e08 9
failed."

And stacktrace is:
" at MyApplication.M ainForm.Initial izeComponent()
at Myapplication.M ainForm..ctor() in
C:\Work\MyAppli cation\Source\M ainForm.vb:line 23"

Now why does that happen? I would understand if I would use Demand-action on
the permission but why can't I get the LinkDemand to work? Should I do some
declarative stuff on MyApplication as well?

Regards,
- Petri