Unshared scratch space

• US 6,584,495 B1
• Filed: 01/30/1998
• Issued: 06/24/2003
• Est. Priority Date: 01/30/1998
• Status: Expired due to Term

• Current Assignee: Zhigu Holdings Limited
• Original Assignee: Microsoft Corporation
• Inventors: Toutonghi, Michael, Jerger, Michael, Bisset, Jeffrey A.
• Primary Examiner(s): Maung, Zarni
• Assistant Examiner(s): OPIE, GEORGE L
• Application Number:
  US09/016,880
• Time in Patent Office: 1,971 Days
• Field of Search: 709/1, 709/100, 709/104, 709/208-209, 709/211-212, 709/216, 709/223, 709/227-229, 709/231, 709/203, 717/168
• US Class Current: 709/217
• CPC Class Codes: G06F 21/52 during program execution, e.g. stack integrity ; Preventing unwanted data erasure; Buffer overflow

Abstract

A computerized method provides unshared local storage space to a process distributed by a trusted source through the use of an identity associated with the process that specifies local capabilities for the identity on a computer. The method obtains the identity and allocates the local storage space based on the information on the local capabilities, securing the space with the identity so that only a process with the same identity can access the space. The method also enforces the local capabilities on the process by monitoring the use of the local storage space. The identity is uniquely defined by a digital certificate or similar security facility. The identity is associated with a data structure, such as a digital signature, that includes the size of the local storage space and, optionally, whether the process is subject to global storage limits set by the computer. A computerized system which executes the method is also disclosed.

Claims

1. A computerized method for providing unshared access to local persistent storage space on a local computer to a program executing on the local computer on behalf of a securely certified identity, the method comprising the steps of:

determining the identity on which behalf the program is executing on the local computer from a secure certificate;

determining local capabilities requested by the identity for the program from the secure certificate, the local capabilities specifying an amount of local persistent storage space;

allocating the local persistent storage space on a persistent storage media to the program for unshared access during execution thereof on the local computer as specified by the local capabilities requested by the identity;

associating the local persistent storage space with the identity; and

limiting access to the persistent storage by the program to the allocated local persistent storage space.

2. The method of claim 1, further comprising the step of monitoring use of the persistent storage media by the program to enforce the local capabilities requested by the program.

3. The method of claim 1, wherein the program has a digital signature encoded with the local capabilities requested by the process.

4. The method of claim 2, wherein the local capabilities comprise a maximum allowed size of local persistent storage space allocated to the identity, and wherein the step of monitoring the use of the persistent storage media comprises the step of determining if the maximum allowed size for the local persistent storage space for the identity has been exceeded.

5. The method of claim 4, wherein the local capabilities further comprise an applicability of a global limit for local persistent storage space to the identity, and wherein the step of monitoring the use of the persistent storage media further comprises the step of determining if the global limit for local storage space has been exceeded when the maximum allowed size has been exceeded and the global limit is applicable to the identity.

6. The method of claim 1, wherein the program has a certificate uniquely identifying the identity.

7. The method of claim 1, wherein the principal is the provider of a remotely-sourced program executing the process.

8. A computer-readable medium having computer-executable instructions for performing steps that cause a local computer to provide unshared storage space on a persistent storage medium to a process executing on behalf of an identity, the steps comprising:

determining the identity on which behalf the process is executing;

obtaining a digital certificate for the process, the digital certificate specifying a request for local capabilities including local storage space on the persistent storage medium for the identity;

decoding the digital certificate to establish local capabilities requested for the identity;

allocating the local storage space to the process as specified by the local capability request;

associating the local storage space with the identity; and

limiting access to the persistent storage by the program to the allocated local persistent storage space.

9. The computer-readable medium of claim 8, further comprising computer-executable instructions for performing the step of monitoring use of the local storage space by the process to enforce the local capabilities requested by the process.

10. The computer-readable medium of claim 9, wherein the step of monitoring comprises computer-executable instructions for performing the step of determining if a macimum allowed size for local storage space for the identity has been exceeded.

11. The computer-readable medium of claim 10, wherein the step of monitoring further comprises computer-executable instructions for performing the step of determining if a global limit for local storage space has been exceeded when the maximum allowed size has been exceeded and the local capabilities specify that the global limit is applicable.

12. A computer-readable medium having stored thereon a data structure associated with an identity, the data structure comprising:

a first data field containing data that uniquely identifies the identity;

a second data field containing data representing local storage capabilities requested for the identity identified by the first data field, the local storage capabilities including a size of a local storage space on a persistent storage medium of the local computer; and

executable code for executing a process on behalf of the identity identified by the data in the first data field, wherein the process is constrained by the local storage capability request represented by data in the second data field to have unshared access to only local storage space allocated as specified in the request on the persistent storage medium.

13. The computer-readable medium of claim 12, wherein the second data field comprises a third data field containing data representing a maximum size of the local storage space permitted to be allocated to the process executing on behalf of the identity identified by the first data field.

14. The computer-readable medium of claim 13, wherein the second data field further comprises a fourth data field containing data representing an applicability of a global limit on a size of the local storage space if the size of the local storage space exceeds the maximum size represented by data in the first data field.

15. A computerized system comprising:

a server operative for transferring executable code for a process using a communications medium; and

a client operative for receiving the process, for determining an identity for the process, and for decoding an infrastructure component identified by the identity to determine a local persistent storage space capability limiting the process to unshared access to an amount of local persistent storage on the client, the client comprising a local persistent storage medium for retaining data used by the process;

the client further operative for assigning local storage space on the persistent storage medium to the process and for monitoring the use of the local persistent storage medium by the process for compliance with the requested capability.

16. A computerized client that manages local space allocated on a local computer to a process, the computerized client comprising:

a persistent storage medium;

a client storage manager module operative for determining an identity and local persistent storage capability for the process when executed on the client, and allocating local space on the persistent storage medium for unshared access by the process as requested for the identity; and

a client monitor module operative for monitoring access by the process to the persistent storage medium and limiting access to the persistent storage medium by the process to said unshared access to the allocated local space.

17. The computerized client of claim 16, wherein the client monitor module enforces local capabilities requested by the identity on the use of the allocated local space by the process.