Edit

Share via


CodeAccessPermission Class

Definition

Caution

Code Access Security is not supported or honored by the runtime.

Defines the underlying structure of all code access permissions.

[System.Obsolete("Code Access Security is not supported or honored by the runtime.", DiagnosticId="SYSLIB0003", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public abstract class CodeAccessPermission : System.Security.IPermission, System.Security.IStackWalk
[System.Serializable]
public abstract class CodeAccessPermission : System.Security.IPermission, System.Security.IStackWalk
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class CodeAccessPermission : System.Security.IPermission, System.Security.IStackWalk
public abstract class CodeAccessPermission : System.Security.IPermission, System.Security.IStackWalk
Inheritance
CodeAccessPermission
Derived
Attributes
Implements

Examples

The following code example shows a permission derived from the CodeAccessPermission class.

//#define debug
// This custom permission is intended only for the purposes of illustration.
// The following code shows how to create a custom permission that inherits
// from CodeAccessPermission. The code implements all required overrides.
// A wildcard character ('*') is implemented for the Name property.
using System;
using System.Security;
using System.Security.Permissions;
using System.IO;
using System.Security.Policy;
using System.Collections;
using System.Text;

[assembly:System.Reflection.AssemblyKeyFile("Key.snk")]
[assembly:System.Security.AllowPartiallyTrustedCallersAttribute()]

namespace MyPermission
{
    [Serializable()] sealed public class   NameIdPermission : CodeAccessPermission, IUnrestrictedPermission
    {
        private String m_Name;
        private bool m_Unrestricted;

        public  NameIdPermission(String name)
        {
            m_Name = name;
        }

        public  NameIdPermission(PermissionState state)
        {
            if (state == PermissionState.None)
            {
                m_Name = "";
            }
            else
                if (state == PermissionState.Unrestricted)
            {
                throw new ArgumentException("Unrestricted state is not allowed for identity permissions.");
            }
            else
            {
                throw new ArgumentException("Invalid permission state.");
            }
        }

        public String Name
        {
            set{m_Name = value;}
            get{ return m_Name;}
        }
        public override IPermission Copy()
        {
            string name = m_Name;
            return new  NameIdPermission( name );
        }
        public bool IsUnrestricted()
        {
            // Always false, unrestricted state is not allowed.
            return m_Unrestricted;
        }

        private bool VerifyType(IPermission target)
        {
            return (target is  NameIdPermission);
        }
        public override bool IsSubsetOf(IPermission target)
        {
#if(debug)
            Console.WriteLine ("************* Entering IsSubsetOf *********************");
#endif
            if (target == null)
            {
                Console.WriteLine ("IsSubsetOf: target == null");
                return false;
            }
#if(debug)

            Console.WriteLine ("This is = " + (( NameIdPermission)this).Name);
            Console.WriteLine ("Target is " + (( NameIdPermission)target).m_Name);
#endif
            try
            {
                 NameIdPermission operand = ( NameIdPermission)target;

                // The following check for unrestricted permission is only included as an example for
                // permissions that allow the unrestricted state. It is of no value for this permission.
                if (true == operand.m_Unrestricted)
                {
                    return true;
                }
                else if (true == this.m_Unrestricted)
                {
                    return false;
                }

                if (this.m_Name != null)
                {
                    if (operand.m_Name == null) return false;

                    if (this.m_Name == "") return true;
                }

                if (this.m_Name.Equals (operand.m_Name))
                {
                    return true;
                }
                else
                {
                    // Check for wild card character '*'.
                    int i = operand.m_Name.LastIndexOf ("*");

                    if (i > 0)
                    {
                        string prefix = operand.m_Name.Substring (0, i);

                        if (this.m_Name.StartsWith (prefix))
                        {
                            return true;
                        }
                    }
                }

                return false;
            }
            catch (InvalidCastException)
            {
                throw new ArgumentException (String.Format ("Argument_WrongType", this.GetType ().FullName));
            }
        }
        public override IPermission Intersect(IPermission target)
        {
            Console.WriteLine ("************* Entering Intersect *********************");
            if (target == null)
            {
                return null;
            }
#if(debug)
            Console.WriteLine ("This is = " + (( NameIdPermission)this).Name);
            Console.WriteLine ("Target is " + (( NameIdPermission)target).m_Name);
#endif
            if (!VerifyType(target))
            {
                throw new ArgumentException (String.Format ("Argument is wrong type.", this.GetType ().FullName));
            }

             NameIdPermission operand = ( NameIdPermission)target;

            if (operand.IsSubsetOf (this)) return operand.Copy ();
            else if (this.IsSubsetOf (operand)) return this.Copy ();
            else
                return null;
        }

        public override IPermission Union(IPermission target)
        {
#if(debug)
            Console.WriteLine ("************* Entering Union *********************");
#endif
            if (target == null)
            {
                return this;
            }
#if(debug)
            Console.WriteLine ("This is = " + (( NameIdPermission)this).Name);
            Console.WriteLine ("Target is " + (( NameIdPermission)target).m_Name);
#endif
            if (!VerifyType(target))
            {
                throw new ArgumentException (String.Format ("Argument_WrongType", this.GetType ().FullName));
            }

             NameIdPermission operand = ( NameIdPermission)target;

            if (operand.IsSubsetOf (this)) return this.Copy ();
            else if (this.IsSubsetOf (operand)) return operand.Copy ();
            else
                return null;
        }
        
        
        
        
       public override void FromXml(SecurityElement e)
        {
            // The following code for unrestricted permission is only included as an example for
            // permissions that allow the unrestricted state. It is of no value for this permission.
            String elUnrestricted = e.Attribute("Unrestricted");
            if (null != elUnrestricted)
            {
                m_Unrestricted = bool.Parse(elUnrestricted);
                return;
            }

            String elName = e.Attribute( "Name" );
            m_Name = elName == null ? null : elName;
        }
        public override SecurityElement ToXml()
        {
            // Use the SecurityElement class to encode the permission to XML.
            SecurityElement esd = new SecurityElement("IPermission");
            String name = typeof( NameIdPermission).AssemblyQualifiedName;
            esd.AddAttribute("class", name);
            esd.AddAttribute("version", "1.0");

            // The following code for unrestricted permission is only included as an example for
            // permissions that allow the unrestricted state. It is of no value for this permission.
            if (m_Unrestricted)
            {
                esd.AddAttribute("Unrestricted", true.ToString());
            }
            if (m_Name != null) esd.AddAttribute( "Name", m_Name );
            return esd;
        }
     }
}

Remarks

Caution

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.

Code access permissions use a stack walk to ensure that all callers of the code have been granted a permission. If a permission object is null, it is handled the same as a permission object with the state PermissionState.None.

The call stack is typically represented as growing down, so that methods higher in the call stack call methods lower in the call stack.

Inheritors of the CodeAccessPermission class must be granted full trust to function correctly as permissions extending the security infrastructure. To determine that the inheritors are fully trusted, CodeAccessPermission issues an InheritanceDemand for ControlEvidence = true and ControlPolicy = true.

Notes to Implementers

When you inherit from CodeAccessPermission, you must also implement the IUnrestrictedPermission interface.

The following CodeAccessPermission members must be overridden: Copy(), Intersect(IPermission), IsSubsetOf(IPermission), ToXml(), FromXml(SecurityElement), and Union(IPermission).

You must also define a constructor that takes a PermissionState as its only parameter.

You must apply the SerializableAttribute attribute to a class that inherits from CodeAccessPermission.

Constructors

CodeAccessPermission()

Initializes a new instance of the CodeAccessPermission class.

Methods

Assert()

Declares that the calling code can access the resource protected by a permission demand through the code that calls this method, even if callers higher in the stack have not been granted permission to access the resource. Using Assert() can create security issues.

Copy()

When implemented by a derived class, creates and returns an identical copy of the current permission object.

Demand()

Forces a SecurityException at run time if all callers higher in the call stack have not been granted the permission specified by the current instance.

Deny()
Obsolete.
Obsolete.

Prevents callers higher in the call stack from using the code that calls this method to access the resource specified by the current instance.

Equals(Object)

Determines whether the specified CodeAccessPermission object is equal to the current CodeAccessPermission.

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
FromXml(SecurityElement)

When overridden in a derived class, reconstructs a security object with a specified state from an XML encoding.

GetHashCode()

Gets a hash code for the CodeAccessPermission object that is suitable for use in hashing algorithms and data structures such as a hash table.

GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
Intersect(IPermission)

When implemented by a derived class, creates and returns a permission that is the intersection of the current permission and the specified permission.

IsSubsetOf(IPermission)

When implemented by a derived class, determines whether the current permission is a subset of the specified permission.

MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
PermitOnly()

Prevents callers higher in the call stack from using the code that calls this method to access all resources except for the resource specified by the current instance.

RevertAll()

Causes all previous overrides for the current frame to be removed and no longer in effect.

RevertAssert()

Causes any previous Assert() for the current frame to be removed and no longer in effect.

RevertDeny()
Obsolete.
Obsolete.

Causes any previous Deny() for the current frame to be removed and no longer in effect.

RevertPermitOnly()

Causes any previous PermitOnly() for the current frame to be removed and no longer in effect.

ToString()

Creates and returns a string representation of the current permission object.

ToXml()

When overridden in a derived class, creates an XML encoding of the security object and its current state.

Union(IPermission)

When overridden in a derived class, creates a permission that is the union of the current permission and the specified permission.

Applies to

Product Versions (Obsolete)
.NET (8 (package-provided), 9 (package-provided))
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7 (package-provided), 4.7, 4.7.1 (package-provided), 4.7.1, 4.7.2 (package-provided), 4.7.2, 4.8 (package-provided), 4.8, 4.8.1
.NET Standard 2.0 (package-provided)
Windows Desktop 3.0, 3.1 (5, 6, 7, 8, 9)