BIOS SMI Handler Injects Files into OS Runtime
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Solution Overview
Problem
Current methods for BIOS to install files into an operating system are cumbersome, as they require embedding file system drivers, increasing BIOS size and risking system functionality, and are costly due to licensing issues and encryption limitations.
Innovation Solution
A System Management Interrupt (SMI) handler within the BIOS enables file injection into the operating system's runtime environment without a file system driver, using a thread creation function to store files durably without altering disk checksums.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the BIOS uses a file system driver to install files into the operating system, then the file can be installed into the file system, but the BIOS size increases and maintenance becomes burdensome
Solution Approach 1:
The patent extracts the file installation capability from the traditional file system driver approach. Instead of embedding a full file system driver in the BIOS, the invention uses the SMI handler to directly inject files into the operating system's runtime environment, separating the file injection function from the BIOS firmware structure.
Solution Approach 2:
The patent introduces an intermediary mechanism - the SMI handler acting as a mediator between the BIOS and the operating system. This handler creates a bridge that allows file injection without requiring the BIOS to directly interact with the file system through a driver, thus avoiding the complexity of embedding file system drivers.
2Ease of manufacture
If the BIOS uses a file system driver to install files, then file installation is possible, but system functionality may be disabled due to checksum changes
Solution Approach 1:
The patent removes the file installation process from the traditional file system driver path that modifies disk checksums. By injecting files directly into the operating system's runtime environment through the SMI handler, the method avoids altering disk-based file system structures and their associated checksums, thereby preventing system functionality disruptions.
Solution Approach 2:
The patent creates a copy of the file in the operating system's runtime environment rather than modifying the original file system structure on disk. This copying approach allows the file to be available to the operating system without changing the durably stored data on disk, thus preserving checksum integrity.
3Ease of manufacture
If the BIOS includes licensing technology from third parties to write to the file system, then file installation capability is improved, but cost increases
Solution Approach 1:
The patent enables the BIOS to perform file installation tasks using its own built-in SMI handler capabilities, without requiring external third-party licensing. The SMI handler provides self-sufficient file injection functionality by directly interacting with the operating system's runtime environment, eliminating the need for licensed file system driver technology from external vendors.
4Ease of manufacture
If the file system is encrypted and the BIOS tries to write to it, then file installation may be achieved, but the process becomes burdensome and expensive
Solution Approach 1:
The patent extracts the file installation process from the encrypted file system path. By injecting files directly into the operating system's runtime environment through the SMI handler, the method bypasses the need to access or write to the encrypted file system on disk, thus avoiding the complexity of cryptographic key management and encrypted storage operations.
Solution Approach 2:
The SMI handler serves as an intermediary that mediates between the BIOS and the operating system, allowing file injection without direct access to the encrypted file system. This intermediary approach avoids the need for the BIOS to handle encryption/decryption operations and key management, simplifying the overall process.
Data Source
AI summary
Techniques for the BIOS to install a file into the runtime environment of an operating system of a computer. A system management interrupt (SMI) handler, resident within the BIOS, receives a first request. The SMI handler identifies an address in memory at which a first file is to be stored, and determines how to access a function provided by a kernel of the operating system. The SMI handler calls the function using the address as an argument to create a thread in the runtime environment of the operating system. Upon the SMI handler receiving a request from the thread, the SMI handler stores a second file in the memory of the runtime environment of the operating system. The thread may, but need not, store the second file to a file system provided by the operating system. In this way, the BIOS need not include a driver to the file system.