Research On Key Technologies For Access Control Of High-level Secure Operating System

With the continuous advancement of the information age, the use of computersgradually changed the way how people work and live, but the increasingly rampantactivities of viruses and hackers made the security of information systems becomeincreasingly prominent. So to develop a high security operating system with our ownintellectual property is imminent. Then the access control is one of the keytechnologies for system security. Therefore, studying the key technology for operatingaccess control and making it meet the requirements of high-grade operating systemsecurity has an important practical significance for the promotion of nationalinformation system-level protection system and the construction of the informationsystem.There are usually two ways on the research and development of secure operatingsystem. The first is to consider the high-security features at the beginning of operatingsystem design; the second is to do reinforcement on the lower security level of theoperating system (such as a variety of Linux systems). For the first secure operatingsystem considered the demand for security before it was designed, so it is very easy tomeet the security needs for the applications developed on this system, but it is veryhard to master the design period as well as its difficulty. Up to now, most of secureoperating system’s research and developments are based on the second way, which isrelatively easy to meet the demands for safety. Then, everything has two sides: somany versions of the operating system and constantly updated kernel seriouslyhindered the enhancement of system security, so the research of this paper focuses onit.The object of this paper is Debian5.0Linux with kernel version2.6.26. On thisbasis, do some security reinforcement to achieve the security needs for Grade Fourprotection system.This article summarizes the key issues of the operating system access control asthe following three aspects: subject and object sensitivity label, access control logicand system compatibility and efficiency.Firstly, it is full marking the subjects and objects. According to the provisions ofthe security operating system for Level Four or higher level in GB17859-1999, thehigh level of security operating system requires for mandatory access control’scoverage to full access control requirements. More specifically, Level Four operatingsystem requires that the trusted computing base should directly or indirectly give the implementation of mandatory access control to all resources of the external main body[1]. Sensitivity label is a basis for implementation of access control. That is, binding allsubjects (such as users, processes), object (such as processes, storage object, and input/output resources) to their corresponding sensitivity label.Secondly, it is access control logic. In this paper, according to the analysis theaccess control classical models, such as BLP model and BIBA model, RBAC model,and DTE model; the actual needs of the system and the focus of the various models,the access control logic is designed, and then the above model is applied to Level fourLinux security subsystem, which is realized the access control for the executableprogram and files.Thirdly, it is system compatibility and efficiency. In my study, accompany withincreasing the sensitivity label for subject/object in the system kernel and using themandatory access control logic to enhance the security of Linux systems, and with theapplication of LSM mechanism of Linux systems, the user interface of originalsystem call remains the same, so the development of security generally does not affectthe compatibility of the Linux system. However, due to the sensitivity label of accesscontrol are put into the core of critical data structures, as well as by adding accesscontrol logic in the key points of the system implementation process, the efficiency ofthe system is affected to some degree. The main purpose in security operating systemis to pursue the security of the system rather than the efficiency and versatility. In mystudy, under the premise of fully guarantee the security of the system, the systemefficiency in the implementation is fully taking into account, such as, discretionaryaccess control and mandatory access control should make full use of the memorybuffer, as far as possible reduce the number of times to deal with the disk, andminimize the impact of security development to the Linux efficiency.