Providing a secure execution mode in a pre-boot environment

• US 10,275,598 B2
• Filed: 04/06/2015
• Issued: 04/30/2019
• Est. Priority Date: 11/27/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Zimmer, Vincent J., Bigbee, Bryant E., Fish, Andrew J., Doran, Mark S.
• Primary Examiner(s): Najjar, Saleh
• Assistant Examiner(s): Pan, Peiliang
• Application Number:
  US14/679,145
• Publication Number:
  US 20150213269A1
• Time in Patent Office: 1,485 Days
• Field of Search: 713 1, 713 2
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 21/575 Secure boot
• CPC Class Codes: G06F 2221/034 Test or assess a computer or a system
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57
• CPC Class Codes: G06F 9/4406 Loading of operating system
• CPC Class Codes: G06F 9/4416 Network booting; Remote initial program loading [RIPL]

Abstract

In one embodiment, the present invention includes a method to establish a secure pre-boot environment in a computer system and performs at least one secure operation in the secure environment. In one embodiment, the secure operation may be storage of a secret in the secure pre-boot environment.

Claims

1. A method comprising:

providing control to firmware responsive to a power-up event in a computer system;

establishing a secure pre-boot environment in response to a determination that a processor in said system is security enabled;

generating a digest including information about the computer system in the secure pre-boot environment;

initializing said processor before a trusted operating system is loaded in said system;

generating a secret in the form of a root key, sealing the root key using a key accessible only to a fixed token secured to a motherboard of the computer system, storing the secret in the fixed token secured to the motherboard of the computer system while in the pre-boot environment and releasing the root key to the computer system only while in the secure pre-boot environment;

transferring the computer system from the secure pre-boot environment including a secure mode to an operating system environment and maintaining the secure mode of the secure pre-boot environment in a background of the operating system environment to maintain platform integrity; and

receiving system management interrupts in a secure virtual machine monitor in the secure pre-boot environment and in the operating system environment if the operating system environment is not a secure environment, otherwise receiving the system management interrupts in the secure virtual machine monitor of the operating system environment.

2. The method of claim 1 including updating a flash memory in the secure pre-boot environment.

3. The method of claim 1 further comprising issuing a system management command in the secure pre-boot environment to secure a system management base address to prevent non-secure pre-boot components from accessing system management random access memory.

4. The method of claim 1 further comprising isolating harmful code from verifiable code.

5. The method of claim 1 including determining if a processor of the computer system is security enabled prior to creating the secure environment.

6. The method of claim 5 further including completing a power on self-test based on determining the processor if the computer system is not security enabled.

7. A non-transitory computer readable medium storing instructions to cause a computer system to:

provide control to firmware responsive to a power-up event;

establish a secure pre-boot environment in response to a determination that a processor in said system is security enabled, said secure pre-boot environment to store code to perform cryptographic computations before booting;

generate a digest including information about the computer system in the secure pre-boot environment;

initialize said processor before a trusted operating system is loaded in said system;

storing instructions to generate a secret in the form of a root key, seal the root key using a key accessible only to a fixed token secured to a motherboard of the computer system, store the secret in the fixed token secured to the motherboard of the computer system while in the pre-boot environment and release the root key to the computer system only while in the secure pre-boot environment;

storing instructions to transfer the computer system from the secure pre-boot environment including a secure mode to an operating system environment and maintain the secure mode of the secure pre-boot environment in a background of the operating system environment to maintain platform integrity; and

storing instructions to receive system management interrupts in a secure virtual machine monitor in the secure pre-boot environment and in the operating system environment if the operating system environment is not a secure environment, otherwise receive the system management interrupts in the secure virtual machine monitor of the operating system environment.

8. The medium of claim 7 further storing instructions to update a flash memory in the secure pre-boot environment.

9. The medium of claim 7 further storing instructions to issue a system management command in the secure pre-boot environment to secure a system management base address to prevent non-secure pre-boot components from accessing system management random access memory.

10. The medium of claim 7 further storing instructions to isolate harmful code from verifiable code.

11. The medium of claim 7 further storing instructions to handle a write to a memory page including a single bit error using the maintained secure pre-boot environment to maintain the platform integrity.

12. The medium of claim 7 further storing instructions to determine via firmware whether a processor has the ability to accommodate secure pre-boot mode operation and, based on the determination via firmware, to further determine whether the processor is configured to operate in secure boot mode at the time of the determination via firmware.