Method and apparatus to retain applet security privileges outside of the Java virtual machine

• US 6,941,552 B1
• Filed: 07/30/1998
• Issued: 09/06/2005
• Est. Priority Date: 07/30/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Nizinski, Leonard Robert Jr., Brown, Michael Wayne, Rothert, Douglas S., Beadle, Bruce Anthony
• Primary Examiner(s): An, Meng-Al T.
• Assistant Examiner(s): ANYA, CHARLES E
• Application Number:
  US09/126,683
• Time in Patent Office: 2,595 Days
• Field of Search: 713164-167, 713/200, 717147-148, 717/7, 712/202, 712/245, 718/1, 718/100, 709200-253, 709102-106
• US Class Current: 718/1
• CPC Class Codes: G06F 21/52 during program execution, e.g. stack integrity ; Preventing unwanted data erasure; Buffer overflow
• CPC Class Codes: G06F 9/4484 Executing subprograms

Abstract

The Java Virtual Machine (JVM) can be decoupled from its Java-enabled browser. To maintain access to certain system resources (a “privilege”) by applets, each Java thread that enables the privilege will now create an entry that describes the privilege in a linked list based on the stack frame address. Sufficient information is stored in the link list for validation purposes. Further, system classes that require specific privileges will have them implicitly granted by an implicit privilege list.

Claims

1. A process for providing a security privilege for a method of a current thread that is currently executing in a run-time environment in a data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the process comprising the computer-implemented steps of:

using a thread identifier of the current thread, locating a linked list;

searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension comprising security privilege information for the method; and

retrieving the security privilege information for a matching entry from the linked list if a matching entry is found in response to a request to retrieve privileges for the method.

2. The process of claim 1, wherein the step of locating a linked list further comprises:

locating the linked list within a stack frame shadow apparatus comprising a plurality of linked lists, each linked list of the plurality of linked lists being associated with a thread.

3. The process of claim 1 wherein the stack frame extension further comprises the stack frame pointer of the method and validation information.

4. The process of claim 3 wherein the validation information comprises the name of the method, the signature of the method, and the return address of the method.

5. The process of claim 1, further comprising:

adding an entry to the linked list if no matching entries are found in response to a request to enable a privilege for the method.

6. A process for providing a privilege for a method of a current thread that is currently executing in a run-time environment in a data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the process comprising the computer-implemented steps of:

using a thread identifier of the current thread, locating a linked list;

searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension; and

removing a matching entry from the linked list if a matching entry is found in response to a request to revert a privilege for the method.

7. A process for providing a privilege for a method of a current thread that is currently executing in a run-time environment in a data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the process comprising the computer-implemented steps of:

using a thread identifier of the current thread, locating a linked list;

searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension; and

retrieving privilege information and validation information for a matching entry from the linked list if a matching entry is found in response to a request to retrieve privileges for the method.

8. A process for enabling and reverting a privilege for a method of a current thread that is currently executing in a run-time environment in a data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the process comprising the computer-implemented steps of:

storing privilege information in a stack frame shadow apparatus to enable a privilege for a method;

querying a stack frame shadow apparatus for privilege information for a method; and

deleting privilege information in a stack frame shadow apparatus to revert a privilege for a method.

9. A data structure on a computer-readable medium for use in a data processing system, the data structure comprising:

a set of stack frame extensions, wherein a stack frame extension comprises;

a pointer to a stack frame for a method;

a data field for privilege data for the method;

a data field for validation data for the method;

a linked list of stack frame extension entries, wherein the linked list is identifiable by a thread identifier.

18. The data structure of claim 9, wherein the privilege data for the method is security privilege data for the method.

10. A data processing system for providing a security privilege for a method of a current thread that is currently executing in a run-time environment in the data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the data processing system comprising:

locating means for locating a linked list using a thread identifier of the current thread;

searching means for searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension comprising security privilege information for the method; and

retrieving means for retrieving the security privilege information for a matching entry from the linked list if a matching entry is found in response to a request to retrieve privileges for the method.

11. The data processing system of claim 10 further comprising:

a stack frame shadow apparatus comprising a plurality of linked lists, each linked list of the plurality of linked lists being associated with a thread.

12. The data processing system of claim 10 wherein the stack frame extension further comprises the stack frame pointer of the method and validation information.

13. The data processing system of claim 12 wherein the validation information comprises the name of the method, the signature of the method, and the return address of the method.

14. The data processing system of claim 10 further comprising:

adding means for adding an entry to the linked list if no matching entries are found in response to a request to enable a privilege for the method.

15. A data processing system for providing a privilege for a method of a current thread that is currently executing in a run-time environment in the data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the data processing system comprising:

locating means for locating a linked list using a thread identifier of the current thread;

searching means for searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension; and

removing means for removing a matching entry from the linked list if a matching entry is found in response to a request to revert a privilege for the method.

16. A data processing system for providing a privilege for a method of a current thread that is currently executing in a run-time environment in the data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the data processing system comprising:

locating means for locating a linked list using a thread identifier of the current thread;

searching means for searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension; and

retrieving means for retrieving privilege information and validation information for a matching entry from the linked list if a matching entry is found in response to a request to retrieve privileges for the method.

17. A computer program product for use in a data processing system for providing a security privilege for a method of a current thread that is currently executing in a run-time environment in the data processing system, the run-time environment having a stack comprising stack frames with stack frame pointers for associated methods, the computer program product comprising:

first instructions for locating a linked list using a thread identifier of the current thread;

second instructions for searching the linked list for an entry having a stack frame pointer that matches the stack frame pointer of the method, wherein an entry of the linked list is a stack frame extension comprising security privilege information for the method; and

third instructions for retrieving the security privilege information for a matching entry from the linked list if a matching entry is found in response to a request to retrieve privileges for the method.