Core initialization code validation

• US 7,853,780 B2
• Filed: 07/31/2008
• Issued: 12/14/2010
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Oracle America, Inc. (Oracle Corporation)
• Inventors: Dik, Casper H., Vesseur, Joep J., Rotondo, Scott A.
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US12/183,859
• Publication Number:
  US 20100031012A1
• Time in Patent Office: 866 Days
• Field of Search: 713/2
• US Class Current: 713/2
• CPC Class Codes: G06F 21/00 Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
• CPC Class Codes: G06F 21/575 Secure boot

Abstract

Files essential to the boot sequence are validated as they are executed. As core boot files are loaded and executed by a computers a hash of the files is created and extended into configuration registers. Core operating system files are verified by the boot loader using a digital signature, and the public key used to verify the digital signature is recorded in a configuration register. Core operating system files verified by the boot loader include a list of hash values, which is used by the operating system to validate the other files as they are executed. User assurance that the system has booted correctly is achieved by comparing the state of configuration registers to previously stored values reflecting the expected state of the registers. Upon the state of the configuration registers matching what is expected, data previously selected by the user is retrieved and recognized by the user.

Claims

1. A computer system for validating initializing code, the computer system comprising:

a central processing unit capable of executing instructions embodied as software; and

a plurality of software portions, wherein

a first one of said software portions is configured to initiate loading of core boot components;

a second one of said software portions is configured to generate hash values for the core boot components;

a third one of said software portions is configured to store the generated hash values in at least one configuration register;

a fourth one of said software portions is configured to retrieve from a trusted source an expected state of the at least one configuration register storing the generated hash values;

a fifth one of said software portions is configured to compare the expected state of the at least one configuration register to the stored hash values;

responsive to the expected state of the at least one configuration register matching the stored hash values, a sixth one of said software portions is configured to retrieve from the trusted source an expected state of a hash value of a hash list;

a seventh one of said software portions is configured to compare the expected state of the hash value of the hash list to a computed hash value of the hash list;

responsive to the expected state of the hash value of the hash list matching the computed hash value of the hash list, an eighth one of said software portions is configured to use the hash list to validate core computer system files,

wherein the core boot components comprise the second one of said software portions.

2. The computer system of claim 1 wherein core boot components include a basic input/output system (“

BIOS”

), a boot loader, and a, set of operating system primary kernel components, wherein the BIOS comprises the second one of said software portions.

3. The computer system of claim 1 wherein the trusted source is a trusted platform module.

4. The computer system of claim 3 wherein the expected state is sealed into the trusted platform module.

5. The computer system of claim 1 wherein retrieval of the expected state of the hash value of the hash list from the trusted sources validates core boot components of the computer system.

6. The computer system of claim 1 wherein the hash list validates files executed by the computer system.

7. The computer system of claim 1, wherein the fifth one of said software portions is configured to compare the expected state of the at least one configuration register to the stored hash values after the first one of said software portions is executed.

8. The computer system of claim 1, wherein the core boot components further comprise the first one of said software portions and the third one of said software portions.