Patent ID: 11921858
Assignee: DELL PRODUCTS L.P.
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A method for protecting against alterations in chain sequencing in an information handling system, the information handling system comprising a BIOS memory medium storing a set of BIOS instructions executable to process code in a firmware volume, wherein the firmware volume comprises a start address, code forming part of a boot process and a pointer to a next firmware volume, the method comprising:
storing, in a root of trust memory medium of the information handling system, a chain of trust database comprising a set of chains of trust, wherein each chain of trust specifies a plurality of entities in a sequence originating from the root of trust;
determining a chain of trust for a boot process;
validating, by the root of trust, the sequence of the plurality of entities for the boot process; and
transitioning, by the root of trust, control from a previous entity to a next entity in the sequence,
wherein the validating and the transitioning comprises:
verifying a first entity in the selected chain of trust;
storing a root of trust identifier as a previous entity identifier;
setting a sequence count to zero;
sending a next entity identifier to the root of trust;
incrementing the sequence count;
receiving a next entity identifier;
retrieving, based on the sequence count and the selected chain of trust, a correct transition link between the previous entity and the next entity;
comparing the received next entity identifier with the stored previous entity identifier based on the sequence count;
notifying the BIOS if the received next entity identifier matches the stored previous entity identifier; and
determining if the sequence count in the root of trust is valid.