<%
'=======================================================================================================================
' Controller Registry
' Provides a whitelist of valid controllers to prevent code injection attacks
'=======================================================================================================================

Class ControllerRegistry_Class
    Private m_controllers

    Private Sub Class_Initialize()
        Set m_controllers = Server.CreateObject("Scripting.Dictionary")
        m_controllers.CompareMode = 1 ' vbTextCompare for case-insensitive

        ' Register all valid controllers here
        ' Format: m_controllers.Add "controllername", True
        RegisterController "homecontroller"
        RegisterController "errorcontroller"
    End Sub

    Private Sub Class_Terminate()
        Set m_controllers = Nothing
    End Sub

    '---------------------------------------------------------------------------------------------------------------------
    ' Register a controller as valid
    '---------------------------------------------------------------------------------------------------------------------
    Public Sub RegisterController(controllerName)
        Dim key : key = LCase(Trim(controllerName))
        If Not m_controllers.Exists(key) Then
            m_controllers.Add key, True
        End If
    End Sub

    '---------------------------------------------------------------------------------------------------------------------
    ' Check if a controller is registered (valid)
    '---------------------------------------------------------------------------------------------------------------------
    Public Function IsValidController(controllerName)
        Dim key : key = LCase(Trim(controllerName))
        IsValidController = m_controllers.Exists(key)
    End Function

    '---------------------------------------------------------------------------------------------------------------------
    ' Get list of all registered controllers
    '---------------------------------------------------------------------------------------------------------------------
    Public Function GetRegisteredControllers()
        GetRegisteredControllers = m_controllers.Keys()
    End Function

    '---------------------------------------------------------------------------------------------------------------------
    ' Validate controller name format (alphanumeric and underscore only)
    '---------------------------------------------------------------------------------------------------------------------
    Public Function IsValidControllerFormat(controllerName)
        If IsEmpty(controllerName) Or Len(controllerName) = 0 Then
            IsValidControllerFormat = False
            Exit Function
        End If

        Dim i, ch
        For i = 1 To Len(controllerName)
            ch = Mid(controllerName, i, 1)
            ' Allow a-z, A-Z, 0-9, and underscore
            If Not ((ch >= "a" And ch <= "z") Or _
                    (ch >= "A" And ch <= "Z") Or _
                    (ch >= "0" And ch <= "9") Or _
                    ch = "_") Then
                IsValidControllerFormat = False
                Exit Function
            End If
        Next

        IsValidControllerFormat = True
    End Function

    '---------------------------------------------------------------------------------------------------------------------
    ' Validate action name format (alphanumeric and underscore only)
    '---------------------------------------------------------------------------------------------------------------------
    Public Function IsValidActionFormat(actionName)
        If IsEmpty(actionName) Or Len(actionName) = 0 Then
            IsValidActionFormat = False
            Exit Function
        End If

        Dim i, ch
        For i = 1 To Len(actionName)
            ch = Mid(actionName, i, 1)
            ' Allow a-z, A-Z, 0-9, and underscore
            If Not ((ch >= "a" And ch <= "z") Or _
                    (ch >= "A" And ch <= "Z") Or _
                    (ch >= "0" And ch <= "9") Or _
                    ch = "_") Then
                IsValidActionFormat = False
                Exit Function
            End If
        Next

        IsValidActionFormat = True
    End Function

End Class

' Singleton instance
Dim ControllerRegistry_Class__Singleton
Function ControllerRegistry()
    If IsEmpty(ControllerRegistry_Class__Singleton) Then
        Set ControllerRegistry_Class__Singleton = New ControllerRegistry_Class
    End If
    Set ControllerRegistry = ControllerRegistry_Class__Singleton
End Function

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