Allowing bypassing of boot validation in a computer system having secure boot enabled by default only under certain circumstances

Patent metadata

Field	Value
Publication number	US-9292302-B2
Application number	US-201313736382-A
Country	US
Kind code	B2
Filing date	Jan 8, 2013
Priority date	Jan 20, 2012
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Provided is a method for temporarily skipping a secure boot function. A computer is configured so that a secure boot function is set as enabled by default. Depression of a power button of the computer in a power-off state generates a startup signal. At the time of startup from S4/S5 state, a switch is turned ON and PP bit indicating physical presence is set at a register. Depression of a specific key on a keyboard causes DE bit to be set at a register. When PP bit and DE bit are found, UEFI firmware stored in a firmware ROM temporarily skips integrity validation of a boot program only for boot this time.

First claim

What is claimed is:

1. A method for loading a boot program without validation of integrity of the boot program in a computer configured to set a secure boot function as enabled by default, the secure boot function being for validation of integrity of a boot program, comprising the steps of:
activating a power supply in response to a startup signal;
generating a first signal indicating physical presence when the startup signal is generated in accordance with an operation by a user who physically accesses the computer in a power-off state;
generating a second signal in accordance with a user's operation for each startup in response to receiving keyboard input from a predefined function key within a predetermined time after startup; and
loading the boot program while skipping the validation of integrity by the secure boot function only for boot this time when the first signal and the second signal are generated, the secure boot function comprising a unified extensible firmware interface (UEFI), the computer having access to at least one boot program that is compatible with the UEFI and at least one boot program that is not compatible with the UEFI, wherein the boot program being loaded while skipping the validation of integrity comprises an operating system that is not compatible with the UEFI.

2. The method according to claim 1 , wherein the loading is executed without rebooting the system.

3. The method according to claim 1 , further comprising the step of requesting input of a password set for the computer, wherein the loading is executed only when the password is authenticated successfully.

4. The method according to claim 1 , wherein when any one of the first signal and the second signal or both of the signals are not generated, the loading is performed after validation of integrity of the boot program.

5. The method according to claim 4 , further comprising the step of, when the validation of integrity fails, selecting another boot device storing a boot program to validate integrity of the boot program stored in the other boot device.

6. The method according to claim 1 , wherein the step of loading the boot program while skipping the validation of integrity includes displaying a selection screen of boot devices.

7. The method according to claim 1 , wherein the step of generating the second signal in accordance with a user's operation includes depression of a key on a keyboard.

8. The method according to claim 1 , wherein, in response to validation of a first finger by a fingerprint authentication device, the startup signal and the first signal are generated, and, in response to validation of a second finger by the fingerprint authentication device, the startup signal, the first signal, and the second signal are generated.

9. A method for booting an operating system without validation of integrity of the operating system in a computer configured to set a secure boot function as enabled by default, the secure boot function being for validation of integrity of an operating system, comprising the steps of:
activating a power supply in response to a startup signal;
generating a first signal indicating physical presence when the startup signal is generated in accordance with an operation by a user who physically accesses the computer in a power-off state;
generating a second signal in accordance with a user's operation before booting the operating system in response to receiving keyboard input from a predefined function key within a predetermined time after startup; and
when the first signal and the second signal are generated, booting the operating system while skipping the validation of integrity by the secure boot function and without rebooting the system, the secure boot function comprising a unified extensible firmware interface (UEFI), the computer having access to at least one boot program that is compatible with the UEFI and at least one boot program that is not compatible with the UEFI, wherein the boot program being loaded while skipping the validation of integrity comprises an operating system that is not compatible with the UEFI.

10. The method according to claim 9 , wherein the first signal and the second signal are cleared before next boot.

11. A computer capable of loading a boot program stored in a storage device, comprising:
a processor;
a non-volatile memory that stores firmware;
a secure boot flag to set a secure boot function as enabled by default, the secure boot function being for validation of integrity of a boot program;
a first flag indicating physical presence that is set when a startup signal is generated by a user who physically accesses the computer in a power-off state; and
a second flag set in accordance with an operation by the user at startup this time in response to receiving keyboard input from a predefined function key within a predetermined time after startup;
wherein when the secure boot flag is set, the processor executing the firmware loads the boot program after the validation of integrity in response to the startup signal, and when the first flag and the second flag are set, the processor loads the boot program while skipping the validation of integrity by the secure boot function in response to the startup signal only for boot this time irrespective of setting of the secure boot flag, the secure boot function comprising a unified extensible firmware interface (UEFI), the computer having access to at least one boot program that is compatible with the UEFI and at least one boot program that is not compatible with the UEFI, wherein the boot program being loaded while skipping the validation of integrity comprises an operating system that is not compatible with the UEFI.

12. The computer according to claim 11 , wherein the second flag is set after generation of the startup signal and before loading of the boot program.

13. The computer according to claim 11 , wherein, when a fingerprint authentication device succeeds in authentication, the first flag and the second flag are set.

14. The computer according to claim 11 , wherein, when a supervisor password is set in the computer and only when the supervisor password is authenticated successfully, the processor executing the firmware skips the validation of integrity.

15. A computer capable of booting an operating system stored in a storage device, comprising:
a processor;
a non-volatile memory that stores firmware;
a secure boot flag to set a secure boot function as enabled by default, the secure boot function being for validation of integrity of an operating system;
a first flag indicating physical presence that is set when a startup signal is generated by a user who physically accesses the computer in a power-off state; and
a second flag set in accordance with an operation by the user before booting the operating system in response to receiving keyboard input from a predefined function key within a predetermined time after startup;
wherein when the secure boot flag is set, the processor executing the firmware loads the operating system after the validation of integrity in response to the startup signal, and when the first flag and the second flag are set, the processor boots the operating system while skipping the validation of integrity by the secure boot function and without rebooting the system in response to the startup signal irrespective of setting of the secure boot flag, the secure boot function comprising a unified extensible firmware interface (UEFI), the computer having access to at least one boot program that is compatible with the UEFI and at least one boot program that is not compatible with the UEFI, wherein

Assignees

• Lenovo Singapore Pte Ltd
• Lenovo Singapore Pte Ltd

Inventors

• Sasaki Ken
• Kasamatsu Eitaroh
• Morishige Yusaku
• Ohtani Kohsuke

Classifications

• G06F9/4406 Primary

  Loading of operating system · CPC title

• G06F9/4401 Primary

  Bootstrapping (security arrangements therefor G06F21/57) · CPC title

• G06F9/44

  Arrangements for executing specific programs · CPC title

• G06F21/575

  Secure boot · CPC title