This is an abstract class for representing the system policy for
Subject-based authorization. A subclass implementation
of this class provides a means to specify a Subject-based
access control Policy.
A Policy object can be queried for the set of
Permissions granted to code running as a
Principal in the following manner:
policy = Policy.getPolicy();
PermissionCollection perms = policy.getPermissions(subject,
codeSource);
The Policy object consults the local policy and returns
and appropriate Permissions object with the
Permissions granted to the Principals associated with the
provided subject, and granted to the code specified
by the provided codeSource.
A Policy contains the following information.
Note that this example only represents the syntax for the default
Policy implementation. Subclass implementations of this class
may implement alternative syntaxes and may retrieve the
Policy from any source such as files, databases,
or servers.
Each entry in the Policy is represented as
a grant entry. Each grant entry
specifies a codebase, code signers, and Principals triplet,
as well as the Permissions granted to that triplet.
grant CodeBase ["URL"], Signedby ["signers"],
Principal [Principal_Class] "Principal_Name" {
Permission Permission_Class ["Target_Name"]
[, "Permission_Actions"]
[, signedBy "SignerName"];
};
The CodeBase and Signedby components of the triplet name/value pairs
are optional. If they are not present, then any any codebase will match,
and any signer (including unsigned code) will match.
For Example,
grant CodeBase "foo.com", Signedby "foo",
Principal com.sun.security.auth.SolarisPrincipal "duke" {
permission java.io.FilePermission "/home/duke", "read, write";
};
This grant entry specifies that code from "foo.com",
signed by "foo', and running as a SolarisPrincipal with the
name, duke, has one Permission. This Permission
permits the executing code to read and write files in the directory,
"/home/duke".
To "run" as a particular Principal,
code invokes the Subject.doAs(subject, ...) method.
After invoking that method, the code runs as all the Principals
associated with the specified Subject.
Note that this Policy (and the Permissions
granted in this Policy) only become effective
after the call to Subject.doAs has occurred.
Multiple Principals may be listed within one grant entry.
All the Principals in the grant entry must be associated with
the Subject provided to Subject.doAs
for that Subject to be granted the specified Permissions.
grant Principal com.sun.security.auth.SolarisPrincipal "duke",
Principal com.sun.security.auth.SolarisNumericUserPrincipal "0" {
permission java.io.FilePermission "/home/duke", "read, write";
permission java.net.SocketPermission "duke.com", "connect";
};
This entry grants any code running as both "duke" and "0"
permission to read and write files in duke's home directory,
as well as permission to make socket connections to "duke.com".
Note that non Principal-based grant entries are not permitted
in this Policy. Therefore, grant entries such as:
grant CodeBase "foo.com", Signedby "foo" {
permission java.io.FilePermission "/tmp/scratch", "read, write";
};
are rejected. Such permission must be listed in the
java.security.Policy.
The default Policy implementation can be changed by
setting the value of the "auth.policy.provider" security property
(in the Java security properties file) to the fully qualified name of
the desired Policy implementation class.
The Java security properties file is located in the file named
<JAVA_HOME>/lib/security/java.security, where <JAVA_HOME>
refers to the directory where the JDK was installed. | 