Design And Implementation Of CentOS Security Management System

In the rapid development of information technology today, operating system security issues still emerge in endlessly, the emergence of a variety of security technologies have not solved security issues completely. Except for the confrontation between invasion technology and security technology, there is another important reason:the system administrator can not use these security technology properly.SeLinux security enhancement model developed by NSA, support TE type enhancement strategy, RBAC role-based access control strategy and MLS multi-level security strategy. Because of its fine-grained access control, SeLinux has the ability to provide the "least privilege principle" policy semantics. However, SeLinux policy configuration is very complex, and configuration language depend strongly on others. And the application requirement is complicated, which lead to the following problems:When the application is configured to run SeLinux permission executable program, it should be the most appropriate set of permissions ε0 so that both the normal operation of the program is not limited, and also to meet the system’s security objectives. If the set of permissions ε is a subset of ε0, then the normal operation of the program is not guaranteed; if the set of permissions ε is a superset of ε0, then the system’s security objectives are not guaranteed. Getting the most appropriate set of permissions of an an executable program Correctly and effectively is complicated and cumbersome, but there is great practical significance.Due to various reasons we need to delete, add, change the security needs of the policy module. And because of the strong dependence between SeLinux configuration language, analysing rules structure and semantics of policy module source code files will be very difficult. Necessary conditions such as consistency between policy and security requirement and non-conflicts among rules should be satisfied after changing policies.On the other hand, the traditional management style which based on the command line and configuration file is inefficient and error prone. Such unfriendly management is incapable of growing complexity of system administration tasks.In view of the above problems, the main work of this paper is as follows:(1) To solve the problems of the most appropriate set of permissions ε0 for the executable program, we develop the Se-PMGS (Policy Module Generation System) based on Rules-Lib. First, we get the subset ε of ε0 by initial configuration of the executable program permission. Then we use the permission updating based on AVC log to supplement ε until we get the most appropriate set of permissions ε0, so that we can meet the system ’s security objectives.(2) We introduce new security requirements for the original policy module problem.So the Se-PMCS (Policy Module Combined System) is achieved. While the original policy documents and new strategy of input file system are consolidating, the duplication of definition, transfer rules of semantic ambiguity, access vector rule conflict will be solved automatically, and we can review of the integrity or confidentiality of data from the strategy and finally output the policy file after the merger. Especially for the complex structure and high coupling degree module, the artificial analysis is difficult, and the Se-PMCS combined system can reflect its advantages better.(3) We design and achieve the CentOS security management system using B/S framework, graphical user interface, and provide the management functions for the administrator including:system information, discretionary access control, mandatory access control resource utilisation, etc.