CA2142: Transparent code should not be protected with LinkDemands


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The latest version of this topic can be found at CA2142: Transparent code should not be protected with LinkDemands.

|Breaking Change|Breaking|

A transparent method requires a LinkDemand or other security demand.

This rule fires on transparent methods which require LinkDemands to access them. Security transparent code should not be responsible for verifying the security of an operation, and therefore should not demand permissions. Because transparent methods are supposed to be security neutral, they should not be making any security decisions. Additionally, safe critical code, which does make security decisions, should not be relying on transparent code to have previously made such a decision.

To fix a violation of this rule, remove the link demand on the transparent method or mark the method with SecuritySafeCriticalAttribute attribute if it is performing security checks, such as security demands.

Do not suppress a warning from this rule.

In the following example, the rule fires on the method because the method is transparent and is marked with a LinkDemand PermissionSet that contains an LinkDemand.

using System;
using System.Security.Permissions;

namespace TransparencyWarningsDemo

    public class TransparentMethodsProtectedWithLinkDemandsClass
        // CA2142 violation - transparent code using a LinkDemand.  This can be fixed by removing the LinkDemand
        // from the method.
        [PermissionSet(SecurityAction.LinkDemand, Unrestricted = true)]
        public void TransparentMethod()

Do not suppress a warning from this rule.