## Permissions

Note: `Permissions` requires the use of Java SecurityManager. Java version 17 deprecated SecurityManager for removal and Java 18 and higher versions, by default, disallow setting SecurityManager at runtime. `Permissions` is thus no longer supported when used in Java 18 or higher versions. Using it in those Java runtime versions will throw a `org.apache.tools.ant.BuildException`. Throwing of `BuildException` can be relaxed by setting the `ant.securitymanager.usage.warn` system or Ant property to `true`, which will then cause a warning to be logged instead of the exception being thrown. Even when `ant.securitymanager.usage.warn` is set to `true`, SecurityManager usage will still be disabled and no security checks will be performed. It is recommended to no longer use `<permissions>`

Permissions represents a set of security permissions granted or revoked to a specific part code executed in the JVM where Apache Ant is running in. The actual Permissions are specified via a set of nested permission items either `<grant>`ed or `<revoke>`d.

In the base situation a base set of permissions granted. Extra permissions can be granted. A granted permission can be overruled by revoking a permission. The security manager installed by the permissions will throw an `SecurityException` if the code subject to these permissions try to use an permission that has not been granted or that has been revoked.

### Nested elements

#### grant

Indicates a specific permission is always granted. Its attributes indicate which permissions are granted.

Attribute | Description | Required
--- | --- | ---
class | The fully qualified name of the Permission class. | Yes
name | The name of the Permission. The actual contents depends on the Permission class. | No
actions | The actions allowed. The actual contents depend on the Permission class and name. | No

Implied permissions are granted.

Please note that some Permission classes may actually need a name and/or actions in order to function properly. The name and actions are parsed by the actual Permission class.

#### revoke

Indicates a specific permission is revoked.

Attribute | Description | Required
--- | --- | ---
class | The fully qualified name of the Permission class. | Yes
name | The name of the Permission. The actual contents depends on the Permission class. | No
actions | The actions allowed. The actual contents depend on the Permission class and name. | No

Implied permissions are not resolved and therefore also not revoked.

The name can handle the * wildcard at the end of the name, in which case all permissions of the specified class of which the name starts with the specified name (excluding the *) are revoked. Note that the - wildcard often supported by the granted properties is not supported. If the name is left empty all names match, and are revoked. If the actions are left empty all actions match, and are revoked.

### Base set

A permissions set implicitly contains the following permissions:

    <grant class="java.net.SocketPermission" name="localhost:1024-" actions="listen">
    <grant class="java.util.PropertyPermission" name="java.version" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vendor" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vendor.url" actions="read">
    <grant class="java.util.PropertyPermission" name="java.class.version" actions="read">
    <grant class="java.util.PropertyPermission" name="os.name" actions="read">
    <grant class="java.util.PropertyPermission" name="os.version" actions="read">
    <grant class="java.util.PropertyPermission" name="os.arch" actions="read">
    <grant class="java.util.PropertyPermission" name="file.encoding" actions="read">
    <grant class="java.util.PropertyPermission" name="file.separator" actions="read">
    <grant class="java.util.PropertyPermission" name="path.separator" actions="read">
    <grant class="java.util.PropertyPermission" name="line.separator" actions="read">
    <grant class="java.util.PropertyPermission" name="java.specification.version" actions="read">
    <grant class="java.util.PropertyPermission" name="java.specification.vendor" actions="read">
    <grant class="java.util.PropertyPermission" name="java.specification.name" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vm.specification.version" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vm.specification.vendor" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vm.specification.name" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vm.version" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vm.vendor" actions="read">
    <grant class="java.util.PropertyPermission" name="java.vm.name" actions="read">

These permissions can be revoked via `<revoke>` elements if necessary.

### Examples

    <permissions>
      <grant class="java.security.AllPermission"/>
      <revoke class="java.util.PropertyPermission"/>
    </permissions>

Grants all permissions to the code except for those handling Properties.

    <permissions>
      <grant class="java.net.SocketPermission" name="foo.bar.com" action="connect"/>
      <grant class="java.util.PropertyPermission" name="user.home" action="read,write"/>
    </permissions>

Grants the base set of permissions with the addition of a `SocketPermission` to connect to `foo.bar.com` and the permission to read and write the `user.home` system property.