1. A Design of Trusted Operating System Based on Linux BY LI HONGJUAN, LANYUQING The presenter Rusul J. ALSaedi Spring 2015 CS 69995- Dr. Rothstein

2. Contents Abstract Introduction Design process of trusted operating system based on Linux Application of the trusted operating system Summary References

3. Abstract Computer technology has developed rapidly. In the same time, it brings more opportunities for information theft, tamper and destruction. Information Security has become a research focus. The security of operating system, as the base of information system, is particularly important. With the developing of 40 years, the security operating system has made certain achievements. However, it still exists some problems. Trusted operating system which is based on trusted computing can help solving the problems. A design process of trusted operating system based on Linux is proposed, and also its architecture is given. A double-key authentication is given as an application example of the trusted operating system.

4. INTRODUCTION Information Security has become the current research focus. Operating System is the most basic and central part of the Information system, once it has been broken through, the attacker can arbitrarily modify any of the contents of the computer. Therefore, it is important to develop a secure and trusted operating system.

5. INTRODUCTION Secure Operating System is designed according to the TCB (Trusted Computing Base), and the basic method is to stand by identity authentication and access control. The Secure Operating System cannot guarantee its self-integrity. TPM (Trusted Platform Module), embedded into a variety of computing terminals, is used to provide infrastructure for more trusted computing.

6. INTRODUCTION Secure operating system in the trusted computing platform is designed based on the TPM. It should follow the trust root and trust chain theory, which brings out trusted operating system. Trusted operating system generally refers to an operating system that provides sufficient support for multi-levels security and evidence of correctness to meet a particular set of requirements.

7. INTRODUCTION Vista, a new generation windows operating system, was introduced by Microsoft in 2007, which placed the security in the first place. Vista uses a data protection mechanism called Bit- Locker, which is a full-disk encryption based on hardware. Its key is stored in the TPM. Bit-Locker also stores fingerprints of the systematic documents and their digital signature in the TPM.

8. INTRODUCTION IMA (Integrity Measurement Architecture) is an enhancement of Linux by a TPM-based Linux security module, which is developed by IBM research. Its main goal is to generate verifiable representative information about the software stack running on a Linux system. This information can be used by remote parties to determine the integrity of the execution environment.

9. D ESIGN PROCESS OF TRUSTED OPERRATING SYSTEM BASED ON LINUX A. Designing Method In order to develop a secure operating system on the basis of an existing non-secure operating system, three ways can be adopted: 1.Virtual Machine method 2. Improve/Enhance method 3. Simulation method

10. A. Designing Method Virtual machine method needs the original system’s hardware and structure supporting a virtual machine, and it is difficult to implement a simulation method. Therefore, we select the improve/enhance method. The goal of the trusted operating system is to offer users a trusted computing environment, while the goal of a secure operating system is to provide users with a secure platform basis. Trust includes securing both the connotation and extension. Thus, the developing method and process of a trusted operating system cannot fully follow a secure operating system.

11. A. Designing Method The design process of a trusted operating system is shown as the following: 1. Linux utilities are analyzed by secure-oriented policy, which are divided into two parts: general applications and trusted processes. Trusted processes contain register processes, administrator processes, privileged user processes, etc. They come from two parts: one is the security expansion of the original procedures, and the other is the new programs. They are associated with the security mechanisms core.

12. A. Designing Method 2. They analyzed the security of the Linux system calls one by one. Security inspection policies are given to those system calls which involve security, then corresponding security inspection mechanisms are inserted. Also, they join some new system calls, such as audit, placing security level of subjects/objects, reading security level of subjects/objects and privilege manipulating.

13. A. Designing Method 3. They decompose the core programs into security- related parts and security-unrelated parts. The security- related part means the implementing entities of the system calls that relate to the secure matter. Some security inspections which realize difficultly in the system call layer can be put in the core layer. In addition, some new core programs are created, which can be used as implementing entities of the security verification and of the new system calls.

14. DESIGN PROCESS OF TRUSTED OPERRATING SYSTEM BASED ON LINUX B. Architecture of Trusted Operating System The architecture of the trusted operating system based on Linux consists of three layers; the hardware layer in the bottom, secure core layer in the middle, and the application layer on top. The components of the architecture are explained as the following:

15. B. Architecture of Trusted Operating System 1.Sign and Identification: Sign and Identification mechanism is used to ensure that only legitimate users can access the system resources. It recognizes the true identity of each user and gives a unique identifier for each user. 2. Discretionary Access Control(DAC): Discretionary Access Control mechanism is used to control the access according to the users’ desires. The user would be permitted to access certain resources which are regulated in advance.

16. B. Architecture of Trusted Operating System 3. Mandatory Access Control (MAC): Mandatory Access Control mechanism classifies the system information, and it gives a secure level for every process, file and IPC (Inter Process Communication) object. When a process attempts to access a file in the computer system, the operating system inspects the process with security identification and access means first, then it compares the security level of the process to that of the file. If the result agrees with the rules, the operating system will grant the access.

17. B. Architecture of Trusted Operating System 4. Least Privilege Management: Least Privilege Management is used to divide super-user privileges into a group of fine-grained privileges and delegate them to different system operators and administrators. This makes different system administrators and operators having the least privileges to accomplish their missions.

18. B. Architecture of Trusted Operating System 5. Audit: the audit is used to set the sampling point in the security-related functions to collect audit information. These sampling points are distributed in the system calls and related commands, calling the audit process to record, dump and archive audit information.

19. B. Architecture of Trusted Operating System 6. Trusted Path: Trusted Path is used to guarantee that the user is communicating with the real system. This counteracts attacks through phishing and Trojan horses. 7. Trusted Software: Trusted Software not only provides trusted software environment based on trusted root, but also supplies a full set of TSS(Trusted Software Stack) for upper trusted software’s calling. In addition, they developed Encrypting File System and Double-key Authentication utilizing TSS. Double-key authentication will be introduced in part 3.

20. APPLICATION OF THE TRUSTED OPERATING SYSTEM Double-Key Authentication System is a highly reliable and flexible authentication system for user permissions. User password and USBKEY are both used in it. Combining with TPM unique serial number and independent encryption and decryption systems; it truly achieves physical-level user authentication security.

21. A. Structure There are three layers in the structure. In the application layer, “passwd init” is used to initiate the user’s information. “Login” is used to authenticate the user when he logs in to the system. In the middle layer, “Double-key authentication interface” packages and rewrites the “USB key interface” and “TSS”, which gives the unified interface to the upper application. “USB key interface” provides the operating interface to the USB key device. “TSS” is a set of function interfaces. Key management, storage and sign, and inspection check of TSS are used in this trusted operating system. In the system layer, “system sustain base” provides some services such as USB driver and SSL(Secure Socket Layer).

22. B. Configuration and Using 1.To start the double-key authentication system: USB key should be inserted first to set up authentication data, then using the command “ passwd -D username” to give the permission to those who can use this double-key authentication. 2. To use double-key authentication system: when a user wants to log in to the system, he/she should insert his/her USB key. When it validates, he/she inputs his/her password. 3. To close the double-key authentication system: when you want to close the double-key authentication usage of some users, this command can be used: passwd -R username. They should pay attention to the preservation of authentication devices and password for the super user because once they are lost, super user will not log in to the system.

23. Summary A design process of trusted operating system based on Linux is proposed, and its architecture is given. As an application, a double-key authentication is given. This operating system was developed with CS2C(China Standard Software Company); it is still in research and development. Furthermore, they will pay more attention to trusted measurement in the operating system. As a result, there is no operating system that is secure 100%.

24. References [1]http://ieeexplore.ieee.org/stamp/stamp.jsp?tp= &arnumber=5631891http://ieeexplore.ieee.org/stamp/stamp.jsp?tp= &arnumber=5631891

25. Thank You