' To replace the default security manager with MySecurityManager, add the 
' assembly to the GAC and call MySecurityManager in the
' custom implementation of the AppDomainManager.
Imports System.Collections
Imports System.Net
Imports System.Reflection
Imports System.Security
Imports System.Security.Permissions
Imports System.Security.Policy
Imports System.Security.Principal
Imports System.Threading
Imports System.Runtime.InteropServices
Imports System.Runtime.Hosting



<Assembly: System.Security.AllowPartiallyTrustedCallersAttribute()> 

<Serializable(), SecurityPermissionAttribute(SecurityAction.Demand, Flags:=SecurityPermissionFlag.Infrastructure)> _
Public Class MySecurityManager
    Inherits HostSecurityManager

    Public Sub New()
        Console.WriteLine(" Creating MySecurityManager.")

    End Sub


    Private hostFlags As HostSecurityManagerOptions = HostSecurityManagerOptions.HostDetermineApplicationTrust Or HostSecurityManagerOptions.HostAssemblyEvidence

    Public Overrides ReadOnly Property Flags() As HostSecurityManagerOptions
        Get
            Return hostFlags
        End Get
    End Property

    Public Overrides Function ProvideAssemblyEvidence(ByVal loadedAssembly As [Assembly], ByVal evidence As Evidence) As Evidence
        Console.WriteLine("Provide assembly evidence for: " + IIf(loadedAssembly Is Nothing, "Unknown", loadedAssembly.ToString()) + ".") 'TODO: For performance reasons this should be changed to nested IF statements
        If evidence Is Nothing Then
            Return Nothing
        End If
        evidence.AddAssemblyEvidence(New CustomEvidenceType())
        Return evidence

    End Function 'ProvideAssemblyEvidence

    Public Overrides Function ProvideAppDomainEvidence(ByVal evidence As Evidence) As Evidence
        Console.WriteLine("Provide evidence for the " + AppDomain.CurrentDomain.FriendlyName + " AppDomain.")
        If evidence Is Nothing Then
            Return Nothing
        End If
        evidence.AddHostEvidence(New CustomEvidenceType())
        Return evidence

    End Function 'ProvideAppDomainEvidence

    <SecurityPermissionAttribute(SecurityAction.Demand, Execution:=True), SecurityPermissionAttribute(SecurityAction.Assert, Unrestricted:=True)> _
    Public Overrides Function DetermineApplicationTrust(ByVal applicationEvidence As Evidence, ByVal activatorEvidence As Evidence, ByVal context As TrustManagerContext) As ApplicationTrust
        If applicationEvidence Is Nothing Then
            Throw New ArgumentNullException("applicationEvidence")
        End If
        ' Get the activation context from the application evidence.
        ' This HostSecurityManager does not examine the activator evidence
        ' nor is it concerned with the TrustManagerContext;
        ' it simply grants the requested grant in the application manifest.
        Dim enumerator As IEnumerator = applicationEvidence.GetHostEnumerator()
        Dim activationArgs As ActivationArguments = Nothing
        While enumerator.MoveNext()
            activationArgs = enumerator.Current '
            If Not (activationArgs Is Nothing) Then
                Exit While
            End If
        End While
        If activationArgs Is Nothing Then
            Return Nothing
        End If
        Dim activationContext As ActivationContext = activationArgs.ActivationContext
        If activationContext Is Nothing Then
            Return Nothing
        End If
        Dim trust As New ApplicationTrust(activationContext.Identity)
        Dim asi As New ApplicationSecurityInfo(activationContext)
        trust.DefaultGrantSet = New PolicyStatement(asi.DefaultRequestSet, PolicyStatementAttribute.Nothing)
        trust.IsApplicationTrustedToRun = True
        Return trust

    End Function 'DetermineApplicationTrust
End Class
<Serializable()> _
Public Class CustomEvidenceType
    Inherits EvidenceBase

    Public Sub New()

    End Sub

    Public Overrides Function ToString() As String
        Return "CustomEvidenceType"

    End Function 'ToString
End Class