One more proposed change inline:
On 26/06/2021 12:58 pm, Peter Firmstone wrote:
Summary of Proposed Changes:
1. GuardFactory & GuardFactorySpi to provide hooks for authorization
checks without SecurityManager or Policy. (Note GuardFactory
should never return null and instead return a no-op Guard that
hotspot can optimize out.
2. Existing Permission implementations to be obtained using
GuardFactorySpi implementations, until their removal. Note that
when SecurityManager is stubbed out and Permission implementations
are deprecated for removal, these should no longer be provided by
default, but instead need to be enabled by entries in the
java.security config file, in preparation for their removal.
3. JDK code, no longer call Permission implementations directly,
instances obtained using GuardFactory, only when enabled in the
java.security configuration file.
4. Threads (system and virtual) updated to use a singleton
*unprivileged* AccessControlContext, instead of inherited
AccessControlContext, this is more appropriate for Executors, the
original inherited context was designed before Executors were
introduced.
5. Deprecation for removal of all Permission implementations from the
JDK platform. The existing implementations of Permission
introduce unnecessary complexity; they lack sufficient flexibility
resulting in a proliferation of Permission grants required in
policy files and some make blocking network calls.
6. Introduce a system property to change AccessController default
behaviour, disable the stack walk by default, but allow it to be
re-enabled with a system property, replace the stack walk array
result of ProtectionDomains with an *unprivileged*
AccessControlContext, the SubjectDomainCombiner can replace it
with a, AccessControlContext containing a single element array,
containing one ProtectionDomain with Principals.
7. AccessController::doPrivileged erases the DomainCombiner by
default, deprecate these methods, retain doPrivilegedWithCombiner
methods that preserve the SubjectDomainCombiner. Developers
should replace their doPrivileged methods with
doPrivilegedWithCombiner
8. Deprecate for removal the CodeSource::implies method.
9. Give unique ProtectionDomain's with a meaninful CodeSource to Java
modules mapped to the boot loader, rather than using a Shared
ProtectionDomain with a null CodeSource.
10. Deprecate for removal AccessController::checkPermission and
AccessControlContext::checkPermission methods.
11. Undeprecate AccessController, AccessControlContext,
DomainCombiner, SubjectDomainCombiner and Subject::doAs methods, while
deprecating for removal methods stated in items above.
To clarify what an *unprivileged* AccessControlContext is:
An instance of AccessControlContext, that contains a single
element array, containing a ProtectionDomain, with a non null
CodeSource, containing a null URL.
Retention of AccessController, AccessControlContext, DomainCombiner
and SubjectDomainCombiner and Subject::doAs methods.
Stubbing of SecurityManager and Policy, for runtime backward
compatibility. Update ProtectionDomain::implies method, to *not*
consult with the Policy. Note it's possible to get access to the
ProtectionDomain array contained within AccessControlContext using a
DomainCombiner.
This is backward compatible with existing usages of JAAS and least
painful method of transition for all concerned as well as allowing
complete flexibility of implementation.
Regards,
Peter Firmstone.
On 25/06/2021 3:59 pm, Peter Firmstone wrote:
Thanks Dalibor,
Would targeting Java 18 be practical?
Also it won't take long to code a prototype, just not sure of the
process.
Cheers,
Peter.
On 24/06/2021 9:30 pm, Dalibor Topic wrote:
On 24.06.2021 04:24, Peter Firmstone wrote:
Thanks Andrew,
For the simple case, of replacing the SecurityManager stack walk,
one could use reflection.
Thank you for also confirming that is not possible (or at least
very unlikely) to add a GuardBuilder to Java 8, the proposal is for
JDK code to use a provider mechanism, to intercept permission
checks, so custom authentication layers can be implemented, this
could be accepted in future versions of Java, but not existing. As
it is said, there is no harm in asking.
Generally speaking, adding any public APIs to a platform release
after its specification has been published, is always going to be a
very tall order involving the JCP, among other things. It's not
really worth it, when other technical solutions, such as
multi-release JARs, already exist, that alleviate the necessity.
cheers,
dalibor topic
--
Regards,
Peter Firmstone
0498 286 363
Zeus Project Services Pty Ltd.
