On Tue, 30 Jan 2024 13:56:53 GMT, Daniel Fuchs <dfu...@openjdk.org> wrote:
>> This code change adds an alternative implementation of user-based
>> authorization `Subject` APIs that doesn't depend on Security Manager APIs.
>> Depending on if the Security Manager is allowed, the methods store the
>> current subject differently. See the spec change in the `Subject.java` file
>> for details. When the Security Manager APIs are finally removed in a future
>> release, this new implementation will be only implementation for these
>> methods.
>>
>> One major change in the new implementation is that `Subject.getSubject`
>> always throws an `UnsupportedOperationException` since it has an
>> `AccessControlContext` argument but the current subject is no longer
>> associated with an `AccessControlContext` object.
>>
>> Now it's the time to migrate from the `getSubject` and `doAs` methods to
>> `current` and `callAs`. If the user application is simply calling
>> `getSubject(AccessController.getContext())`, then switching to `current()`
>> would work. If the `AccessControlContext` argument is retrieved from an
>> earlier `getContext()` call and the associated subject might be different
>> from that of the current `AccessControlContext`, then instead of storing the
>> previous `AccessControlContext` object and passing it into `getSubject` to
>> get the "previous" subject, the application should store the `current()`
>> return value directly.
>
> src/java.management/share/classes/com/sun/jmx/remote/security/MBeanServerFileAccessController.java
> line 307:
>
>> 305: AccessController.doPrivileged(new PrivilegedAction<>() {
>> 306: public Subject run() {
>> 307: return Subject.current();
>
> Is the `doPrivileged` still needed here? Is there a chance that
> `Subject.current()` will throw a `SecurityException`, or return a different
> result if a security manager is present and `doPrivileged` is not used?
When a security manager is set, `current()` still calls `getSubject()` and it
needs a permission unless it's called inside `doPrivileged`. But, see the
comment above.
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PR Review Comment: https://git.openjdk.org/jdk/pull/17472#discussion_r1471585097
