Reducing Size and Complexity of the Security-Critical Code Base of File Systems

Date

Feb 13, 2012

Time

1:00 PM - 2:00 PM

Speaker

Dipl.-Inf. Carsten Weinhold

Language

en

Main Topic

Informatik

Other Topics

Informatik

Description

Desktop and mobile computing devices increasingly store critical data, both personal and professional in nature. Yet, the enormous code bases of their monolithic operating systems (hundreds of thousands to millions of lines of code) are likely to contain exploitable weaknesses that jeopardize the security of this data in the file system. Using a highly componentized system architecture based on a microkernel (or a very small hypervisor) can significantly improve security. The individual operating system components have smaller code bases running in isolated address spaces so as to provide better fault containment. Their isolation also allows for smaller trusted computing bases (TCBs) of applications that comprise only a subset of all components. In my thesis, I build VPFS, a virtual private file system that is designed for such a componentized system architecture. It aims at reducing the amount of code and complexity that a file system implementation adds to the TCB of an application. The basic idea behind VPFS is similar to that of a VPN, which securely reuses an untrusted network: The core component of VPFS implements all functionality and cryptographic algorithms that an application needs to rely upon for confidentiality, integrity, and recoverability of file system contents. This security-critical core reuses a much more complex and therefore untrusted file system stack for non-critical functionality and access to the storage device. In my status talk, I will give an overview of related work in the area of cryptographic storage systems and present the VPFS architecture. I will then discuss the current state of my research on how secure cooperation between trusted and untrusted parts of the file system stack can be facilitated.

Last modified: Feb 13, 2012, 8:36:23 AM