File System Case Sensitivity Handling

Solution Overview

Problem

Conventional file systems are vulnerable to security threats due to their inability to effectively handle letter case differences in file names, leading to incorrect file operations and potential malicious file access.

Innovation Solution

The file system is configured to handle letter case differences by allowing individual directories or files to be assigned case sensitive, case insensitive, or case preferring designations, enabling precise matching and preventing case varying duplicate names, thus ensuring secure file operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional file systems use ASCII collation order to identify files, then file system operations can be performed, but security vulnerabilities arise due to case-insensitive matching allowing malicious file access

Engineering Contradiction:

Improvefile system operation reliabilityVSAvoidsecurity vulnerability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by allowing different directories to have different case sensitivity attributes. Some directories can be case-sensitive while others are case-insensitive, enabling security-critical directories to use case-sensitive matching to prevent malicious file access, while non-critical directories maintain case-insensitive behavior for compatibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the case sensitivity behavior configurable and changeable per directory. The file system can dynamically adjust its matching behavior based on the specific directory's attributes, allowing flexibility in balancing security requirements with operational convenience across different parts of the file system.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If file systems allow multiple files with same name varying only in letter case, then file creation flexibility is maintained, but file identification accuracy deteriorates

Engineering Contradiction:

Improvefile naming flexibilityVSAvoidfile name matching accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by allowing different directories to have different case sensitivity attributes. Some directories can be case-sensitive while others are case-insensitive, enabling security-critical directories to use case-sensitive matching to prevent malicious file access, while non-critical directories maintain case-insensitive behavior for compatibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the file system into multiple directories, each with its own case sensitivity attribute. This segmentation allows the file system to handle case sensitivity differently in different locations, enabling precise control over file identification accuracy in security-critical areas while maintaining flexibility elsewhere.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If file systems use case-insensitive matching, then ease of operation is improved, but security against malicious file access deteriorates

Engineering Contradiction:

Improvefile access convenienceVSAvoidmalicious file access

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by allowing different directories to have different case sensitivity attributes. Some directories can be case-sensitive while others are case-insensitive, enabling security-critical directories to use case-sensitive matching to prevent malicious file access, while non-critical directories maintain case-insensitive behavior for compatibility.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12197387B2Techniques for handling letter case in file systems

Publication Date: 2025.01.14 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Described herein are technologies that provide an element of security related to file system operations. Individual nodes in a file system, such as a directory or a file, can be associated with information that describes how to handle letter case when a file name included in a file system operation request is used to locate a file in the file system. For example, a case sensitive designation associated with a directory can require a case sensitive match between a file name included in a request and a file name included in the directory, in order to perform the requested file system operation. In another example, a case preferring designation associated with a directory first checks for a case sensitive match between file names. If a case sensitive match does not exist, then a case insensitive match between the file names can be used to perform the requested file system operation.