Extended File Attributes for Working Directory Security
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern operating systems under the POSIX standard inherit a current working directory (CWD) from the parent process, leading to security concerns and scalability issues when applications create files in widely accessible directories, as existing solutions for restricting directory access are not scalable and cumbersome to configure.
Innovation Solution
The introduction of extended file attributes allows for the specification of a particular directory to be used as the CWD for an application process, enabling the override of the default CWD and allowing or denying the use of directories as CWDs without modifying the application, using attributes like 'trusted.directory.allow' and 'trusted.directory.reject' to enforce security contexts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If applications inherit CWD from parent process under POSIX standard, then ease of operation is improved, but security is worsened due to widely accessible directories
Solution Approach 1:
The patent applies local quality by associating different security attributes with different directories. Each directory can have specific extended attributes (trusted.directory.allow, trusted.directory.reject, trusted.directory.change) that define its access characteristics. This allows the system to maintain CWD inheritance while applying security restrictions at the local directory level rather than globally
Solution Approach 2:
The patent introduces extended file attributes as an intermediary mechanism between the CWD inheritance system and security enforcement. These attributes act as a mediator layer that filters and controls which directories can be inherited as CWD, allowing the system to maintain POSIX compatibility while adding security oversight
2Object-affected harmful factors
If extended file attributes are introduced to control CWD access, then security is improved, but device complexity is worsened
Solution Approach 1:
The patent makes the existing extended file attribute mechanism universal by applying it to CWD control. The same extended attribute infrastructure used for other file security purposes is leveraged for CWD management, avoiding the need for a separate complex system. The attributes serve multiple functions including allowing, rejecting, and changing CWD behavior
Solution Approach 2:
The system uses self-service by allowing directories to declare their own CWD accessibility through extended attributes. Directors can be configured with trusted.directory.allow or trusted.directory.reject attributes that automatically enforce CWD policies without requiring external intervention or complex configuration management
3Object-affected harmful factors
If configuration methods are added to restrict directory access, then security is improved, but ease of operation is worsened due to cumbersome configuration
Solution Approach 1:
The configuration system uses self-service by allowing directories to be automatically tagged with extended attributes that define their CWD policies. Rather than requiring complex external configuration, the system can automatically manage directory attributes based on predefined rules, reducing configuration burden while maintaining security
Data Source
AI summary
A method is described including identifying, in a kernel space, an extended attribute value associated with a shared working directory, wherein the extended attribute value comprises a first session identifier identifying a session. The method also includes determining by comparing the first session identifier to a second session identifier associated with a first application, whether the first application has permission to use the shared working directory.