Providing a Secure Execution Mode in a Pre-Boot Environment

• US 20150213269A1
• Filed: 04/06/2015
• Published: 07/30/2015
• Est. Priority Date: 11/27/2002
• Status: Active Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Zimmer, Vincent J., Bigbee, Bryant E., Fish, Andrew J., Doran, Mark S.
• Granted Patent: US 10,275,598 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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; and

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

2. The method of claim 1 including 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.

3. The method of claim 2 further comprising 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.

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

5. The method of claim 2 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.

6. The method of claim 3 further comprising 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.

7. The method of claim 2 further comprising isolating harmful code from verifiable code.

8. The method of claim 2 including determining if a processor of the computer system is security enabled prior to creating the secure environment.

9. The method of claim 8 further including completing a power on self-test based on determining the processor if the computer system is not security enabled.

10. 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; and

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

11. The medium of claim 10 further 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.

12. The medium of claim 11 further 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.

13. The medium of claim 11 further storing instructions to update a flash memory in the secure pre-boot environment.

14. The medium of claim 11 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.

15. The medium of claim 12 further 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.

16. The medium of claim 11 further storing instructions to isolate harmful code from verifiable code.

17. The medium of claim 11 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.

18. The medium of claim 10 wherein the platform integrity includes handling a write to memory page including a single bit error.

19. The medium of claim 10 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.

20. A computer system comprising:

a processor;

a memory controller coupled to said processor;

a memory coupled to said processor;

secure pre-boot environment logic to provide control to firmware responsive to a power-up event of the processor and to establish a secure pre-boot environment in response to a determination that the processor is security enabled, said secure pre-boot environment to store code to perform cryptographic computations, said logic to generate a digest including information about the system in the secure pre-boot environment;

storage associated with the secure pre-boot environment, said storage to store a secret in the form of a root key and to secure code to perform cryptographic computations; and

firmware logic to initialize said processor before operating system code is loaded, said firmware logic to load the operating system code.

21. The system of claim 20 further including:

at least one storage device containing instructions that, if executed, enable the system to establish the secure pre-boot environment and 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 a computer system; and

perform at least one secure operation in the secure pre-boot environment and release the root key to the system only when in the secure pre-boot environment, after provision of the secret from the storage device to the fixed token for verification.

22. The system of claim 21 further comprising instructions that, if executed, enabled the system to store a secret in the secure pre-boot environment in a mass storage of said system.

23. The system of claim 21 further comprising a flash memory containing secure basic input/output system code.

24. The system of claim 23 further comprising a fixed token secured to a motherboard of the system and including a second processor for attestation of system compliance, coupled to the processor.

25. The system of claim 20 wherein said secure pre-boot environment logic is hardware logic.

26. The system of claim 20 wherein said secure pre-boot environment logic is firmware logic.

27. The system of claim 20 wherein said secure pre-boot environment logic is software logic.

28. The system of claim 20 wherein said secure code to perform assymetric cryptographic computations.

29. A processor comprising:

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

the firmware further comprising logic to determine, during pre-boot, that the processor is security enabled;

logic to establish a secure environment during booting, before operating system code has been loaded;

logic to generate a message digest for use in the secure environment;

storage, associated with the secure environment, to store a secret in the form of a root key;

storage, associated with the secure environment, to store secure code to perform cryptographic computations;

the firmware further comprising logic to perform at least one initialization operation of the processor before said operating system code is loaded; and

the firmware further comprising logic to load the operating system code.

30. The processor of claim 29 wherein said logic to determine is hardware logic.

31. The processor of claim 29 wherein said logic to determine is firmware logic.

32. The processor of claim 29 wherein said logic to determine is software logic.

33. The processor of claim 29 wherein said secure code to perform assymetric cryptographic computations.