System.Security.SuppressUnmanagedCodeSecurityAttribute Class

Summary

Allows managed code to call into unmanaged code without a stack walk. This class cannot be inherited.

C# Syntax:

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method | AttributeTargets.Interface)] public sealed class SuppressUnmanagedCodeSecurityAttribute : Attribute

Use this attribute with extreme care. Incorrect use can create security weaknesses. This attribute can be applied to methods that want to call into native code without incurring the performance loss of a run-time security check when doing so. The stack walk performed when calling unmanaged code is omitted at run time, resulting in substantial performance savings. Using this attribute in a class applies it to all contained methods.

Generally, whenever managed code calls into unmanaged code (by PInvoke or COM Interop into native code), there is a demand for the UnmanagedCode permission to ensure all callers have the necessary permission to allow this. By applying this explicit attribute, developers can suppress the demand at run time. The developer must take responsibility for assuring that the transition into unmanaged code is sufficiently secured by other means. The demand for the UnmanagedCode permission will still occur at link time. For example, if function A calls function B and function B is marked with SuppressUnmanagedCodeSecurityAttribute, function A will be checked for unmanaged code permission during just-in-time compilation, but not subsequently during run time.

This attribute is only effective when applied to PInvoke methods (or classes containing PInvoke methods) or the definition of an interface through which interop calls will be made. It will be ignored in all other contexts.

This attribute is useful for implementing a class that provides access to system resources through unmanaged code. Code that does not have permission to access unmanaged code can call a class with this attribute to access unmanaged code. This is only safe if the writer of the class with this attribute has programmed the class to be secure. If not, this attribute is dangerous and can allow the code that uses it to be misused.

This is not a declarative security attribute, but a regular attribute (it derives from Attribute, not SecurityAttribute).

System.Security Namespace See also:
MSDN: extendingmetadatausingattributes | MSDN: securityoptimizations

System.Security.SuppressUnmanagedCodeSecurityAttribute Member List:

Public Constructors

ctor #1

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

Public Properties

TypeId (inherited from System.Attribute)

Read-only See base class member description: System.Attribute.TypeId When implemented in a derived class, gets a unique identifier for this Attribute.

Public Methods

Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetHashCode (inherited from System.Attribute)	See base class member description: System.Attribute.GetHashCode Returns the hash code for this instance.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
IsDefaultAttribute (inherited from System.Attribute)	See base class member description: System.Attribute.IsDefaultAttribute When overridden in a derived class, returns an indication whether the value of this instance is the default value for the derived class.
Match (inherited from System.Attribute)	See base class member description: System.Attribute.Match When overridden in a derived class, returns a value indicating whether this instance equals a specified object.
ToString (inherited from System.Object)	See base class member description: System.Object.ToString Derived from System.Object, the primary base class for all objects.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

• System.Object
• System.Attribute
• System.Security.SuppressUnmanagedCodeSecurityAttribute

System.Security.SuppressUnmanagedCodeSecurityAttribute Member Details

Summary:

Default constructor. This constructor is called by derived class constructors to initialize state in this type.

C# Syntax:

public SuppressUnmanagedCodeSecurityAttribute();

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Inherited
See base class member description: System.Attribute.TypeId

Summary

When implemented in a derived class, gets a unique identifier for this Attribute.

C# Syntax:

public virtual object TypeId {get;}

As implemented, this identifier is merely the Type of the attribute. However, it is intended that the unique identifier be used to identify two attributes of the same type.

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Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.Finalize

C# Syntax:

~SuppressUnmanagedCodeSecurityAttribute();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Attribute.GetHashCode

Summary

Returns the hash code for this instance.

C# Syntax:

public override int GetHashCode();

Return Value:

A 32-bit signed integer hash code.

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Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Attribute.IsDefaultAttribute

Summary

When overridden in a derived class, returns an indication whether the value of this instance is the default value for the derived class.

C# Syntax:

public virtual bool IsDefaultAttribute();

Return Value:

true if this instance is the default attribute for the class; otherwise, false.

The default implementation of this class returns false, and must be implemented in the derived class to be useful to that class.

The implementation of this method in a derived class compares the value of this instance to a standard, default value obtained by some means, then returns a Boolean value that indicates whether the value of this instance is equal to the standard. The standard value is typically coded as a constant in the implementation, or stored programmatically in a field used by the implementation.

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Inherited
See base class member description: System.Attribute.Match

Summary

When overridden in a derived class, returns a value indicating whether this instance equals a specified object.

C# Syntax:

public virtual bool Match(    object obj );

obj

An Object to compare with this instance of Attribute.

Return Value:

true if this instance equals obj; otherwise, false.

This method determines if one Attribute equals another. Its default implementation is the same as Attribute.Equals, which performs a value and reference comparison. Override this method to implement support for attribute values, such as flags or bitfields, that consist of components that are meaningful in themselves. For example, consider an attribute whose value is a binary field divided into a bitfield of flags. Two instances of this attribute have one flag in set in common while all the other flags differ. The Equal method cannot determine that the two instances have the same flag set, but the Match method can.

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Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.ToString

C# Syntax:

public virtual string ToString();

For more information on members inherited from System.Object click on the link above.

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