SQL Server Programming and Host Protection Attributes

The ability to load and execute managed code in a SQL Server host requires meeting the host's requirements for both code access security and host resource protection. The code access security requirements are specified by one of three SQL Server permission sets: SAFE, EXTERNAL-ACCESS, or UNSAFE. Code executing within the SAFE or EXTERNAL-ACCESS permission sets must avoid certain types or members that have the HostProtectionAttribute attribute applied. The HostProtectionAttribute is not a security permission as much as a reliability guarantee in that it identifies specific code constructs, either types or methods, that the host may disallow. The use of the HostProtectionAttribute enforces a programming model that helps protect the stability of the host.

Note

Code Access Security (CAS) has been deprecated across all versions of .NET Framework and .NET. Recent versions of .NET do not honor CAS annotations and produce errors if CAS-related APIs are used. Developers should seek alternative means of accomplishing security tasks.

Host Protection Attributes

Host protection attributes identify types or members that do not fit the host programming model and represent the following increasing levels of reliability threat:

Are otherwise benign.
Could lead to destabilization of server-managed user code.
Could lead to destabilization of the server process itself.

SQL Server disallows the use of a type or member that has a HostProtectionAttribute that specifies a HostProtectionResource value of SharedState, Synchronization, MayLeakOnAbort, or ExternalProcessMgmt. This prevents the assemblies from calling members that enable sharing state, perform synchronization, might cause a resource leak on termination, or affect the integrity of the SQL Server process.

Disallowed Types and Members

The following table identifies types and members whose HostProtectionResource values are disallowed by SQL Server.

Namespace	Type or member
`Microsoft.Win32`	PowerModeChangedEventArgs class PowerModeChangedEventHandler delegate SessionEndedEventArgs class SessionEndedEventHandler delegate SessionEndingEventArgs class SessionEndingEventHandler delegate SessionSwitchEventArgs class SessionSwitchEventHandler delegate SystemEvents class TimerElapsedEventArgs class TimerElapsedEventHandler delegate UserPreferenceChangedEventArgs class UserPreferenceChangingEventArgs class
`System.Collections`	ArrayList.Synchronized method Hashtable.Synchronized method Queue.Synchronized method SortedList.Synchronized method Stack.Synchronized method
`System.ComponentModel`	AddingNewEventArgs class AddingNewEventHandler delegate ArrayConverter class AsyncCompletedEventArgs class AsyncCompletedEventHandler delegate AsyncOperation class AsyncOperationManager class AttributeCollection class BackgroundWorker class BaseNumberConverter class BindingList<T> class BooleanConverter class ByteConverter class CancelEventArgs class CancelEventHandler delegate CharConverter class CollectionChangeEventArgs class CollectionChangeEventHandler delegate CollectionConverter class ComponentCollection class ComponentConverter class ComponentEditor class ComponentResourceManager class Container class ContainerFilterService class CultureInfoConverter class CustomTypeDescriptor class DateTimeConverter class DecimalConverter class ActiveDesignerEventArgs class ActiveDesignerEventHandler delegate CheckoutException class CommandID class ComponentChangedEventArgs class ComponentChangedEventHandler delegate ComponentChangingEventArgs class ComponentChangingEventHandler delegate ComponentEventArgs class ComponentEventHandler delegate ComponentRenameEventArgs class ComponentRenameEventHandler delegate DesignerCollection class DesignerEventArgs class DesignerEventHandler delegate DesignerOptionService class DesignerTransaction class DesignerTransactionCloseEventArgs class DesignerTransactionCloseEventHandler delegate DesignerVerb class DesignerVerbCollection class DesigntimeLicenseContext class DesigntimeLicenseContextSerializer class MenuCommand class ComponentSerializationService class ContextStack class DesignerLoader class InstanceDescriptor class MemberRelationshipService class ResolveNameEventArgs class ResolveNameEventHandler delegate SerializationStore class ServiceContainer class ServiceCreatorCallback delegate StandardCommands class StandardToolWindows class DoubleConverter class DoWorkEventArgs class DoWorkEventHandler delegate EnumConverter class EventDescriptor class EventDescriptorCollection class EventHandlerList class ExpandableObjectConverter class HandledEventArgs class HandledEventHandler delegate InstanceCreationEditor class Int16Converter class Int32Converter class Int64Converter class InvalidAsynchronousStateException class InvalidEnumArgumentException class BeginInvoke method License class LicenseContext class LicenseException class LicenseManager class LicenseProvider class LicFileLicenseProvider class ListChangedEventArgs class ListChangedEventHandler delegate ListSortDescription class ListSortDescriptionCollection class MaskedTextProvider class MemberDescriptor class MultilineStringConverter class NestedContainer class NullableConverter class ProgressChangedEventArgs class ProgressChangedEventHandler delegate PropertyChangedEventArgs class PropertyChangedEventHandler delegate PropertyDescriptor class PropertyDescriptorCollection class ReferenceConverter class RefreshEventArgs class RefreshEventHandler delegate RunWorkerCompletedEventArgs class RunWorkerCompletedEventHandler delegate SByteConverter class SingleConverter class StringConverter class SyntaxCheck class TimeSpanConverter class TypeConverter class TypeDescriptionProvider class TypeDescriptor class TypeListConverter class UInt16Converter class UInt32Converter class UInt64Converter class WarningException class Win32Exception class
`System.Diagnostics`	Debug.Listeners property Trace.Listeners property EventLog.SynchronizingObject property ConsoleTraceListener class DefaultTraceListener class DelimitedListTraceListener class EventLogTraceListener class PerformanceCounter class PerformanceCounterCategory class Process class ProcessStartInfo class TextWriterTraceListener class TraceListener class XmlWriterTraceListener class TraceSource.Listeners property
`System.IO`	Stream.Synchronized method TextReader.Synchronized method