Programming .NET Components, 2nd Edition

Programmatic Security

Although for the most part administrative security configuration is sufficient, .NET also provides various programmatic ways to control and enforce security. You can use these powerful techniques to tighten security, optimize performance, handle unknown security policies, and deal with questionable components. In addition, programmatic security can configure security at the component level (unlike administrative security configuration, which is only as granular as a single assembly). All the permission types have corresponding classes and attributes available to you. In fact, administrative configuration uses these classes indirectly; the security configuration files are just a list of classes to use when providing the configurable permissions.

Although system administrators can grant assemblies permissions by using administrative configuration, there is no programmatic way to grant permissions. The reason is clear: if that were possible, a rogue assembly could grant itself permissions and go about causing harm. Programmatic security can deny security permissions or demand that some permission be granted. You can use the permission classes dynamically during runtime or apply them as class or assembly attributes, indicating which security action to take and when.

The Permission Classes

The permission types listed in Table 12-1 all have corresponding permission classes, such as the FileIOPermission class or the UIPermission class. Most permission classes are defined ...