Transcript Preoyati Khan`s presentation

Design and Implementation of
Security Operating System based on
Trusted Computing
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AUTHORS – X. NIE, D. FENG, J. CHE, X. WANG
PRESENTED BYPREOYATI KHAN
KENT STATE UNIVERSITY
Contents
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•Introduction
•Trusted computing platform
•Security model for trusted computing
•Security operating system for trusted computing
•Experiment and Performance
•Conclusions
Introduction
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 Analyzes and reviews relative work of security
operating system based on trusted computing.
 Classical security model BLP is improved to get
IBLP.
 The overall design scheme and modularized
implementation of a secure system for trusted
computing.
 Experiment result to show effectiveness and
feasibility of their system.
Trusted computing
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 Behavior is predictable in any operating condition.
 Highly resistant to subversion by application
software, viruses and a given level of physical
interference.
Trusted Computing Platform
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 Allows systems to extend trust to clients running on
these platforms.
 Provides open platforms: wide availability, diverse
hardware types, and the ability to run many
applications from many mutually distrusting sources
while still retaining trust in clients.
Trusted Computing Platform(cont.)
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 TCPA/TCG structure contains 4 essential factors.
1.
TPM(Trusted Platform Module).



2.
CRTM( Core Root Trust Module).

3.
Initializes entire systems and authenticates BIOS.
TCPA OS.


4.
Core of hardware level security framework.
Generates encryption key.
Protects BIOS and the OS from malicious activity.
Supports hardware modules and applications.
Launches TCPA control function .
Compatibility.

Allows the existing computer system hardware foundation to
exists continuously.
Trusted Computing Platform(cont.)
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TCPA Application
TCPA Operating System
TPM
CRTM
Trusted Part
CPU
Other Chips
Present Part
Figure1: TCPA/TCG system structure
Security model for trusted computing
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 BLP model: simulates a computer system accord
with military security policy.
 In BLP there are 4 access attributes:




e access (execute with neither observe nor alter)
r access (observe with no alter)
a access (alter with no observe)
w access (both observe and alter)
Security model for trusted computing(cont.)
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 BLP denotes B(S,O,A) to denote the current access
state set.
 S - set of subject
 O - set of object
 A - access attribute, consists of e access, r access, a
access and w access.
Security model for trusted computing
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 Two important axiom: ss- property and star
property.
 Simple security(ss-property):
 * Property (Star property):
Security model for trusted computing
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 Problems with BLP model:
 Trusted subject does not have star property constraint
 Too large access privilege
 Does not match minimum privilege principle.
 Lack of integrity control.
Design of IBLP security model
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 The authors of this paper designed a security model
based on trusted computing through the
improvement of BLP and called it IBLP.
Definition of IBLP
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Security attribute.
1.
•
Security attribute for each subject and object includes


Confidentiality level Sc
Integrity level Si
Access category sets Ca
2. Security domain.
•
The security domain of subject S can be classified as
common subject C and trusted subject T.
Axiom of IBLP
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1.
Simple security property(Ss-property).
1 and 2 :

common subject can neither observe nor execute information of the object on
the


higher confidentiality level.
lower integrity level.
3 and 4 :


Trusted subject on the lower confidentiality level can neither observe nor
execute information of the object on the higher confidentiality level.
But can observe and execute information of the object, lower integrity level.
Axiom of IBLP
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1.
Star-property.
5 and 6 :

common subject can only alter information of the object on the same
confidentiality and integrity level .
7 and 8 :

Trusted subject on the lower integrity level can not alter information
of object on the higher integrity level but can alter information of
object on the lower confidentiality level.
Axiom of IBLP
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1.
Simple security property(Ss-property).
2. Star-property.
Analysis of IBLP
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1.
Consistent with the basic security feature of BLP.


ss-property of IBLP is consistent with the ss-property of
BLP.
The star property of IBLP can be seen a special case of the
star-property of BLP.
2. Meets the principle of minimum privilege.
3. Prevents the occurrence of covert channel.
4. Meets the security requirement of trusted
computing in a more flexible way.
Security operating system for trusted computing
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Figure 2. The overall design
Security operating system for trusted computing
(cont.)
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 Modular implementation:
 Modularly developed and implemented on an open code Linux
environment.
 Trusted identification:
 Is used to ensure that only legitimate users can access the
system resources.
Security operating system for trusted computing
(cont.)
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 Privileged access control:
 Ensures that a trusted process only gets the security privilege
that meets the requirement of its task.
 Discretionary access control:
 Uses ACL defined by user to implement access control of
resources.
 <Type, Id, Perm>
 Mandatory access control:
 Manages system resources by classifying them according to
their security level.
Security operating system for trusted computing
(cont.)
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 Integrity Measurement:

Mainly protects the content continuously loaded by OS after secure boot of
TPM.
Figure 3: TPM-based Integrity Measurement
Security operating system for trusted computing
(cont.)
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 Security audit:
 Audits any security related events
 Generate and reveal secret information for system manager to
control security situation.
Experiment and Performance
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 Security Function:
 Can detect and defend most of the attack at present.
Table 1. Rate of detection for typical attack.
Attack
type
IP
cheating
Buffer
Overflow
Denial of
Service
Rootkit
Rate of
detection
80%
85%
87%
95%
Experiment and Performance(cont.)
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 Decline of Performance:
 The decline rate of efficiency is no more than 10%
Table 2. decline rate of efficiency.
Test
project
Test ipc
Test fork
Test fs
Decline rate
8%
10%
10%
Conclusions
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 Improved traditional security model BLP, and
designed a trusted computing based security model
IBLP.
 Presented the design and implementation of a secure
operating system for trusted computing platform.
Conclusions(cont.)
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 Will improve the system to be more compatible with
the security requirement of trusted computing
application.
 Will adopt optimizations algorithms to improve the
performance.
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Thank
You