There is only one Policy object installed in the runtime at any
* given time. A Policy object can be installed by calling the
* setPolicy method. The installed Policy object can be
* obtained by calling the getPolicy method.
*
*
If no Policy object has been installed in the runtime, a call to
* getPolicy installs an instance of the default Policy
* implementation (a default subclass implementation of this abstract class).
* The default Policy implementation can be changed by setting the value
* of the "policy.provider" security property (in the Java security properties
* file) to the fully qualified name of the desired Policy subclass
* implementation. The Java security properties file is located in the
* file named <JAVA_HOME>/lib/security/java.security.
* <JAVA_HOME> refers to the value of the java.home system property,
* and specifies the directory where the JRE is installed.
*
*
Application code can directly subclass Policy to provide a custom
* implementation. In addition, an instance of a Policy object can be
* constructed by invoking one of the getInstance factory methods
* with a standard type. The default policy type is "JavaPolicy".
*
*
Once a Policy instance has been installed (either by default, or by
* calling setPolicy),
* the Java runtime invokes its implies when it needs to
* determine whether executing code (encapsulated in a ProtectionDomain)
* can perform SecurityManager-protected operations. How a Policy object
* retrieves its policy data is up to the Policy implementation itself.
* The policy data may be stored, for example, in a flat ASCII file,
* in a serialized binary file of the Policy class, or in a database.
*
*
The This method traverses the list of registered security providers,
* starting with the most preferred Provider.
* A new Policy object encapsulating the
* PolicySpi implementation from the first
* Provider that supports the specified type is returned.
*
* Note that the list of registered providers may be retrieved via
* the {@link Security#getProviders() Security.getProviders()} method.
*
* @param type the specified Policy type. See the Policy section in the
*
* Java Cryptography Architecture Standard Algorithm Name Documentation
* for a list of standard Policy types.
*
* @param params parameters for the Policy, which may be null.
*
* @return the new Policy object.
*
* @exception SecurityException if the caller does not have permission
* to get a Policy instance for the specified type.
*
* @exception NullPointerException if the specified type is null.
*
* @exception IllegalArgumentException if the specified parameters
* are not understood by the PolicySpi implementation
* from the selected Provider.
*
* @exception NoSuchAlgorithmException if no Provider supports a PolicySpi
* implementation for the specified type.
*
* @see Provider
* @since 1.6
*/
public static Policy getInstance(String type, Policy.Parameters params)
throws NoSuchAlgorithmException {
checkPermission(type);
try {
GetInstance.Instance instance = GetInstance.getInstance("Policy",
PolicySpi.class,
type,
params);
return new PolicyDelegate((PolicySpi)instance.impl,
instance.provider,
type,
params);
} catch (NoSuchAlgorithmException nsae) {
return handleException(nsae);
}
}
/**
* Returns a Policy object of the specified type.
*
* A new Policy object encapsulating the
* PolicySpi implementation from the specified provider
* is returned. The specified provider must be registered
* in the provider list.
*
* Note that the list of registered providers may be retrieved via
* the {@link Security#getProviders() Security.getProviders()} method.
*
* @param type the specified Policy type. See the Policy section in the
*
* Java Cryptography Architecture Standard Algorithm Name Documentation
* for a list of standard Policy types.
*
* @param params parameters for the Policy, which may be null.
*
* @param provider the provider.
*
* @return the new Policy object.
*
* @exception SecurityException if the caller does not have permission
* to get a Policy instance for the specified type.
*
* @exception NullPointerException if the specified type is null.
*
* @exception IllegalArgumentException if the specified provider
* is null or empty,
* or if the specified parameters are not understood by
* the PolicySpi implementation from the specified provider.
*
* @exception NoSuchProviderException if the specified provider is not
* registered in the security provider list.
*
* @exception NoSuchAlgorithmException if the specified provider does not
* support a PolicySpi implementation for the specified type.
*
* @see Provider
* @since 1.6
*/
public static Policy getInstance(String type,
Policy.Parameters params,
String provider)
throws NoSuchProviderException, NoSuchAlgorithmException {
if (provider == null || provider.length() == 0) {
throw new IllegalArgumentException("missing provider");
}
checkPermission(type);
try {
GetInstance.Instance instance = GetInstance.getInstance("Policy",
PolicySpi.class,
type,
params,
provider);
return new PolicyDelegate((PolicySpi)instance.impl,
instance.provider,
type,
params);
} catch (NoSuchAlgorithmException nsae) {
return handleException (nsae);
}
}
/**
* Returns a Policy object of the specified type.
*
* A new Policy object encapsulating the
* PolicySpi implementation from the specified Provider
* object is returned. Note that the specified Provider object
* does not have to be registered in the provider list.
*
* @param type the specified Policy type. See the Policy section in the
*
* Java Cryptography Architecture Standard Algorithm Name Documentation
* for a list of standard Policy types.
*
* @param params parameters for the Policy, which may be null.
*
* @param provider the Provider.
*
* @return the new Policy object.
*
* @exception SecurityException if the caller does not have permission
* to get a Policy instance for the specified type.
*
* @exception NullPointerException if the specified type is null.
*
* @exception IllegalArgumentException if the specified Provider is null,
* or if the specified parameters are not understood by
* the PolicySpi implementation from the specified Provider.
*
* @exception NoSuchAlgorithmException if the specified Provider does not
* support a PolicySpi implementation for the specified type.
*
* @see Provider
* @since 1.6
*/
public static Policy getInstance(String type,
Policy.Parameters params,
Provider provider)
throws NoSuchAlgorithmException {
if (provider == null) {
throw new IllegalArgumentException("missing provider");
}
checkPermission(type);
try {
GetInstance.Instance instance = GetInstance.getInstance("Policy",
PolicySpi.class,
type,
params,
provider);
return new PolicyDelegate((PolicySpi)instance.impl,
instance.provider,
type,
params);
} catch (NoSuchAlgorithmException nsae) {
return handleException (nsae);
}
}
private static Policy handleException(NoSuchAlgorithmException nsae)
throws NoSuchAlgorithmException {
Throwable cause = nsae.getCause();
if (cause instanceof IllegalArgumentException) {
throw (IllegalArgumentException)cause;
}
throw nsae;
}
/**
* Return the Provider of this Policy.
*
* This Policy instance will only have a Provider if it
* was obtained via a call to This Policy instance will only have a type if it
* was obtained via a call to This Policy instance will only have parameters if it
* was obtained via a call to Applications are discouraged from calling this method
* since this operation may not be supported by all policy implementations.
* Applications should solely rely on the The default implementation of this method returns
* Policy.UNSUPPORTED_EMPTY_COLLECTION. This method can be
* overridden if the policy implementation can return a set of
* permissions granted to a CodeSource.
*
* @param codesource the CodeSource to which the returned
* PermissionCollection has been granted.
*
* @return a set of permissions granted to the specified CodeSource.
* If this operation is supported, the returned
* set of permissions must be a new mutable instance
* and it must support heterogeneous Permission types.
* If this operation is not supported,
* Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
*/
public PermissionCollection getPermissions(CodeSource codesource) {
return Policy.UNSUPPORTED_EMPTY_COLLECTION;
}
/**
* Return a PermissionCollection object containing the set of
* permissions granted to the specified ProtectionDomain.
*
* Applications are discouraged from calling this method
* since this operation may not be supported by all policy implementations.
* Applications should rely on the The default implementation of this method first retrieves
* the permissions returned via This method can be overridden if the policy implementation
* supports returning a set of permissions granted to a ProtectionDomain.
*
* @param domain the ProtectionDomain to which the returned
* PermissionCollection has been granted.
*
* @return a set of permissions granted to the specified ProtectionDomain.
* If this operation is supported, the returned
* set of permissions must be a new mutable instance
* and it must support heterogeneous Permission types.
* If this operation is not supported,
* Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
*
* @since 1.4
*/
public PermissionCollection getPermissions(ProtectionDomain domain) {
PermissionCollection pc = null;
if (domain == null)
return new Permissions();
if (pdMapping == null) {
initPolicy(this);
}
synchronized (pdMapping) {
pc = pdMapping.get(domain.key);
}
if (pc != null) {
Permissions perms = new Permissions();
synchronized (pc) {
for (Enumeration The default implementation of this method does nothing.
* This method should be overridden if a refresh operation is supported
* by the policy implementation.
*/
public void refresh() { }
/**
* This subclass is returned by the getInstance calls. All Policy calls
* are delegated to the underlying PolicySpi.
*/
private static class PolicyDelegate extends Policy {
private PolicySpi spi;
private Provider p;
private String type;
private Policy.Parameters params;
private PolicyDelegate(PolicySpi spi, Provider p,
String type, Policy.Parameters params) {
this.spi = spi;
this.p = p;
this.type = type;
this.params = params;
}
@Override public String getType() { return type; }
@Override public Policy.Parameters getParameters() { return params; }
@Override public Provider getProvider() { return p; }
@Override
public PermissionCollection getPermissions(CodeSource codesource) {
return spi.engineGetPermissions(codesource);
}
@Override
public PermissionCollection getPermissions(ProtectionDomain domain) {
return spi.engineGetPermissions(domain);
}
@Override
public boolean implies(ProtectionDomain domain, Permission perm) {
return spi.engineImplies(domain, perm);
}
@Override
public void refresh() {
spi.engineRefresh();
}
}
/**
* This represents a marker interface for Policy parameters.
*
* @since 1.6
*/
public static interface Parameters { }
/**
* This class represents a read-only empty PermissionCollection object that
* is returned from the refresh method causes the policy object to
* refresh/reload its data. This operation is implementation-dependent.
* For example, if the policy object stores its data in configuration files,
* calling refresh will cause it to re-read the configuration
* policy files. If a refresh operation is not supported, this method does
* nothing. Note that refreshed policy may not have an effect on classes
* in a particular ProtectionDomain. This is dependent on the Policy
* provider's implementation of the implies
* method and its PermissionCollection caching strategy.
*
* @author Roland Schemers
* @author Gary Ellison
* @see java.security.Provider
* @see java.security.ProtectionDomain
* @see java.security.Permission
*/
public abstract class Policy {
/**
* A read-only empty PermissionCollection instance.
* @since 1.6
*/
public static final PermissionCollection UNSUPPORTED_EMPTY_COLLECTION =
new UnsupportedEmptyCollection();
/** the system-wide policy. */
private static Policy policy; // package private for AccessControlContext
private static final Debug debug = Debug.getInstance("policy");
// Cache mapping ProtectionDomain.Key to PermissionCollection
private WeakHashMapsetPolicy.
* This method first calls
* SecurityManager.checkPermission with a
* SecurityPermission("getPolicy") permission
* to ensure it's ok to get the Policy object.
*
* @return the installed Policy.
*
* @throws SecurityException
* if a security manager exists and its
* checkPermission method doesn't allow
* getting the Policy object.
*
* @see SecurityManager#checkPermission(Permission)
* @see #setPolicy(java.security.Policy)
*/
public static Policy getPolicy()
{
SecurityManager sm = System.getSecurityManager();
if (sm != null)
sm.checkPermission(SecurityConstants.GET_POLICY_PERMISSION);
return getPolicyNoCheck();
}
/**
* Returns the installed Policy object, skipping the security check.
* Used by SecureClassLoader and getPolicy.
*
* @return the installed Policy.
*
*/
static synchronized Policy getPolicyNoCheck()
{
if (policy == null) {
String policy_class = null;
policy_class = AccessController.doPrivileged(
new PrivilegedActionSecurityManager.checkPermission with a
* SecurityPermission("setPolicy")
* permission to ensure it's ok to set the Policy.
*
* @param p the new system Policy object.
*
* @throws SecurityException
* if a security manager exists and its
* checkPermission method doesn't allow
* setting the Policy.
*
* @see SecurityManager#checkPermission(Permission)
* @see #getPolicy()
*
*/
public static void setPolicy(Policy p)
{
SecurityManager sm = System.getSecurityManager();
if (sm != null) sm.checkPermission(
new SecurityPermission("setPolicy"));
if (p != null) {
initPolicy(p);
}
synchronized (Policy.class) {
Policy.policy = p;
}
}
/**
* Initialize superclass state such that a legacy provider can
* handle queries for itself.
*
* @since 1.4
*/
private static void initPolicy (final Policy p) {
/*
* A policy provider not on the bootclasspath could trigger
* security checks fulfilling a call to either Policy.implies
* or Policy.getPermissions. If this does occur the provider
* must be able to answer for it's own ProtectionDomain
* without triggering additional security checks, otherwise
* the policy implementation will end up in an infinite
* recursion.
*
* To mitigate this, the provider can collect it's own
* ProtectionDomain and associate a PermissionCollection while
* it is being installed. The currently installed policy
* provider (if there is one) will handle calls to
* Policy.implies or Policy.getPermissions during this
* process.
*
* This Policy superclass caches away the ProtectionDomain and
* statically binds permissions so that legacy Policy
* implementations will continue to function.
*/
ProtectionDomain policyDomain =
AccessController.doPrivileged(new PrivilegedActionPolicy.getInstance.
* Otherwise this method returns null.
*
* @return the Provider of this Policy, or null.
*
* @since 1.6
*/
public Provider getProvider() {
return null;
}
/**
* Return the type of this Policy.
*
* Policy.getInstance.
* Otherwise this method returns null.
*
* @return the type of this Policy, or null.
*
* @since 1.6
*/
public String getType() {
return null;
}
/**
* Return Policy parameters.
*
* Policy.getInstance.
* Otherwise this method returns null.
*
* @return Policy parameters, or null.
*
* @since 1.6
*/
public Policy.Parameters getParameters() {
return null;
}
/**
* Return a PermissionCollection object containing the set of
* permissions granted to the specified CodeSource.
*
* implies method
* to perform policy checks. If an application absolutely must call
* a getPermissions method, it should call
* getPermissions(ProtectionDomain).
*
* implies method
* to perform policy checks.
*
* getPermissions(CodeSource)
* (the CodeSource is taken from the specified ProtectionDomain),
* as well as the permissions located inside the specified ProtectionDomain.
* All of these permissions are then combined and returned in a new
* PermissionCollection object. If getPermissions(CodeSource)
* returns Policy.UNSUPPORTED_EMPTY_COLLECTION, then this method
* returns the permissions contained inside the specified ProtectionDomain
* in a new PermissionCollection object.
*
* refresh
* on a file-based policy will cause the file to be re-read.
*
* getPermissions(CodeSource) and
* getPermissions(ProtectionDomain)
* methods in the Policy class when those operations are not
* supported by the Policy implementation.
*/
private static class UnsupportedEmptyCollection
extends PermissionCollection {
private Permissions perms;
/**
* Create a read-only empty PermissionCollection object.
*/
public UnsupportedEmptyCollection() {
this.perms = new Permissions();
perms.setReadOnly();
}
/**
* Adds a permission object to the current collection of permission
* objects.
*
* @param permission the Permission object to add.
*
* @exception SecurityException - if this PermissionCollection object
* has been marked readonly
*/
@Override public void add(Permission permission) {
perms.add(permission);
}
/**
* Checks to see if the specified permission is implied by the
* collection of Permission objects held in this PermissionCollection.
*
* @param permission the Permission object to compare.
*
* @return true if "permission" is implied by the permissions in
* the collection, false if not.
*/
@Override public boolean implies(Permission permission) {
return perms.implies(permission);
}
/**
* Returns an enumeration of all the Permission objects in the
* collection.
*
* @return an enumeration of all the Permissions.
*/
@Override public Enumeration