Method and apparatus for secure management of debugging processes within communication devices

• US 8,438,621 B2
• Filed: 12/21/2007
• Issued: 05/07/2013
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Zhang, Jiang, Chen, Peter, Franks, Bill, Medvinsky, Alexander
• Primary Examiner(s): NGUYEN, THU HA T
• Application Number:
  US11/963,127
• Publication Number:
  US 20090165111A1
• Time in Patent Office: 1,964 Days
• Field of Search: 713/153, 713/155, 713/182, 713/320, 713/172, 713/173, 713/174, 709/203, 709/204, 726/5, 726/34, 726/9, 726/20, 725/25, 380/229
• US Class Current: 726/9
• CPC Class Codes: G06F 21/335 for accessing specific resources, e.g. using Kerberos tickets
• CPC Class Codes: G06F 2221/2151 Time stamp
• CPC Class Codes: H04L 63/0807 using tickets, e.g. Kerberos cryptographic mechanisms or cryptographic arrangements for entity authentication using tickets or tokens H04L9/3213
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources

Abstract

A method, device and system for securely managing debugging processes within a communication device, such as a set top box or other multimedia processing device. For example, a security processor (SP) within the communication device manages the lifetime (LT) of any access token issued for use in activating debugging privileges within the communication device. The security processor authenticates an issued access token and securely delivers appropriate debug authorization information to the device controller. The security processor uses its secure, internal timer to count down the lifetime and update the remaining lifetime of the issued access token during the processing of each command by the security processor. In addition to securely managing the issuance of the access token and it'"'"'s remaining lifetime, the updating process reduces any impact on the normal communications within the device. The method overcomes the issue of the communication device not having a secure internal clock.

Claims

1. A communication device, comprising:

a controller configured to receive multimedia content, wherein the controller includes a debugging process that allows debugging of the controller operating software; and

a security processor coupled to the controller and configured to manage the activation of the debugging process,

wherein the security processor is configured to verify an access token received by the communication device for allowing activation of the debugging process, wherein the access token has a lifetime, wherein the security processor generates a set of debug authorization information in response to verifying the access token,

wherein the controller is configured to authenticate the set of debug authorization information,

wherein the controller is configured to activate the debugging process after successfully authenticating the set of debug authorization information, and

wherein the security processor is configured to instruct the controller to deactivate the debugging process when the lifetime of the access token has expired.

2. The device as recited in claim 1, wherein the security processor is configured to instruct the controller to deactivate the debugging process by:

determining the remaining amount of the lifetime of the access token in response to the security processor receiving a command from the controller,

determining if the lifetime of the access token has expired,

wherein, if the lifetime of the access token has not expired, reducing the remaining amount of the lifetime of the access token based on the amount of time required for the security processor to receive a command from the controller, and

wherein, if the lifetime of the access token has expired, instructing the controller to deactivate the debugging process.

3. The device as recited in claim 2, wherein reducing the remaining amount of the lifetime of the access token includes:

storing by the security processor the lifetime of the access token,

starting a timer within the security processor upon the lifetime of the access token being stored in the security processor,

stopping the timer when the security processor receives a command from the controller,

reducing the lifetime of the access token by the amount of time elapsed on the timer between the last storage of the lifetime of the access token by the security processor and the receipt of the command by the security processor from the controller.

4. The device as recited in claim 3, wherein reducing the remaining amount of the lifetime of the access token includes setting the remaining amount of the lifetime of the access token to zero if the amount of time elapsed on the timer between the storage of the lifetime of the access token by the security processor and the receipt of the command by the security processor from the controller is greater than the remaining amount of the lifetime of the access token stored in the security processor.

5. The device as recited in claim 3, wherein reducing the remaining amount of the lifetime of the access token includes resetting the timer to zero and restarting it in response to reducing the remaining amount of the lifetime of the access token.

6. The device as recited in claim 1, wherein the security processor is configured to notify the controller to transmit updated debugging information to the security processor.

7. The device as recited in claim 1, wherein the security processor is configured to verify the access token received by the communication device by verifying an access token signature in a signature data field of the access token, verifying an access token device ID in a device ID data field of the access token, and verifying an access token sequence number in a sequence number data field of the access token.

8. The device as recited in claim 1, wherein the controller is configured to authenticate the set of debug authorization information generated by the security processor by:

installing a communication device private key to the security processor,

installing a public key corresponding to the communication device private key to the controller,

wherein the security processor signs the set of debug authorization information using the communication device private key to generate a debug authorization information signature and transmits the debug authorization information signature to the controller, and

using a communication device public key to verify the debug authorization information signature.

9. The device as recited in claim 1, wherein the communication device is selected from the group consisting of a signal converter box, a signal decoder box, a digital video recorder, a digital video disk recorder, a personal video recorder device, a set-top box, a home media server, a digital video server, a residential gateway, a video receiver, a cellular telephone, a smartphone, a personal digital assistant (PDA) device, a wireless handheld device, a communication device, a digital camera, a desktop personal computer (PC), a laptop PC and a notebook PC.

10. A method for managing a debugging process within a communication device, wherein the communication device includes a controller and a security processor coupled to the controller, comprising the steps of:

verifying by the security processor an access token received by the communication device for allowing activation of the debugging process, wherein the access token has a lifetime, wherein the security processor generates a set of debug authorization information in response to verifying the access token,

wherein the controller activates the debugging process upon authenticating the set of debug authorization information, and wherein the debugging process allows debugging of the controller operating software; and

instructing by the security processor the controller to deactivate the debugging process when the lifetime of the access token expires,

wherein the instructing step includes

determining the remaining amount of the lifetime of the access token in response to the security processor receiving a command from the controller,

determining if the lifetime of the access token has expired,

if the lifetime of the access token has expired, instructing the controller to deactivate the debugging process within the communication device, and

if the lifetime of the access token has not expired, reducing the remaining amount of the lifetime of the access token based on the amount of time required for the security processor to receive a command from the controller.

11. The method as recited in claim 10, wherein reducing the remaining amount of life of the lifetime of the access token includes:

storing by the security processor the lifetime of the access token,

starting a timer within the security processor upon the lifetime of the access token being stored by the security processor,

stopping the timer when the security processor receives a command from the controller,

reducing the lifetime of the access token by the amount of time elapsed on the timer between the storage of the lifetime of the access token by the security processor and the receipt of the command by the security processor from the controller.

12. The method as recited in claim 11, wherein reducing the remaining amount of life of the lifetime of the access token includes setting the remaining amount of the lifetime of the access token to zero if the amount of time elapsed on the timer between the storage of the lifetime of the access token by the security processor and the receipt of the command by the security processor from the controller is greater than the remaining amount of the lifetime of the access token stored in the security processor.

13. The method as recited in claim 11, wherein reducing the remaining amount of the lifetime of the access token includes resetting the timer to zero in response to reducing the remaining amount of the lifetime of the access token.

14. The method as recited in claim 10, further comprising the step of notifying the controller to transmit updated debugging information to the security processor.

15. The method as recited in claim 10, wherein the access token includes an access token signature in a signature data field, an access token device ID in a device ID data field and an access token sequence number in a sequence number data field, and wherein the step of verifying the access token received by the communication device includes the steps of:

verifying by the security processor the access token signature in the signature data field,

verifying by the security processor the access token device ID in the device ID data field, and

verifying by the security processor the access token sequence number in the sequence number data field.

16. The method as recited in claim 10, further comprising the step of the controller authenticating the set of debug authorization information generated by the security processor, wherein the step of authenticating the set of debug authorization information includes the steps of:

provisioning of the security processor with a device private key,

provisioning of the controller with a public key corresponding to the device private key,

signing by the security processor the debug authorization information using the communication device private key to generate a debug authorization information signature,

using a communication device public key to verify the debug authorization information signature.

17. The method as recited in claim 10, wherein the communication device is selected from the group consisting of a signal converter box, a signal decoder box, a digital video recorder, a digital video disk recorder, a personal video recorder device, a set-top box, a home media server, a digital video server, a residential gateway, a video receiver, a cellular telephone, a smartphone, a personal digital assistant (PDA) device, a wireless handheld device, a communication device, a digital camera, a desktop personal computer (PC), a laptop PC and a notebook PC.

18. A non-transitory computer readable medium storing instructions that, when executed on a programmed processor, carry out a method for managing a debugging process within a communication device, comprising:

instructions for verifying an access token received by the communication device for allowing activation of the debugging process, wherein the access token has a lifetime;

instructions for generating a set of debug authorization information in response to verifying the access token, wherein the controller activates the debugging process upon authenticating the set of debug authorization information, and wherein the debugging process allows debugging of the controller operating software; and

instructions for informing the controller to deactivate the debugging process when the lifetime of the access token expires,

wherein the informing instructions include

instructions for determining the remaining amount of the lifetime of the access token in response to the security processor receiving a command from the controller,

instructions for determining if the lifetime of the access token has expired,

if the lifetime of the access token has expired, instructions for informing the controller to deactivate the debugging feature within the communication device, and

if the lifetime of the access token has not expired, instructions for reducing the remaining amount of the lifetime of the access token based on the amount of time required to receive a command from the controller.