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Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including United States Department of Defense–style mandatory access controls (MAC). SELinux is a set of kernel modifications and user-space tools that have been added to various Linux distributions. Its architecture strives to separate enforcement of security decisions from the security policy itself and streamlines the volume of software charged with security policy enforcement.〔http://www.nsa.gov/research/_files/selinux/papers/slinux.pdf〕 The key concepts underlying SELinux can be traced to several earlier projects by the United States National Security Agency. ==Overview== The United States National Security Agency (NSA), the original primary developer of SELinux, released the first version to the open source development community under the GNU GPL on December 22, 2000.〔 Compare 〕 The software merged into the mainline Linux kernel 2.6.0-test3, released on 8 August 2003. Other significant contributors include Red Hat, Network Associates, Secure Computing Corporation, Tresys Technology, and Trusted Computer Solutions. Experimental ports of the FLASK/TE implementation have been made available via the TrustedBSD Project for the FreeBSD and Darwin operating systems. From NSA Security-enhanced Linux Team: NSA Security-enhanced Linux is a set of patches to the Linux kernel and some utilities to incorporate a strong, flexible mandatory access control (MAC) architecture into the major subsystems of the kernel. It provides an enhanced mechanism to enforce the separation of information based on confidentiality and integrity requirements, which allows threats of tampering and bypassing of application security mechanisms to be addressed and enables the confinement of damage that can be caused by malicious or flawed applications. It includes a set of sample security policy configuration files designed to meet common, general-purpose security goals. SELinux was designed to demonstrate the value of mandatory access controls to the Linux community and how such controls could be added to Linux. Originally, the patches that make up SELinux had to be explicitly applied to the Linux kernel source; SELinux has been merged into the Linux kernel mainline in the 2.6 series of the Linux kernel. Security-Enhanced Linux implements the Flux Advanced Security Kernel (FLASK). Such a kernel contains architectural components prototyped in the Fluke operating system. These provide general support for enforcing many kinds of mandatory access control policies, including those based on the concepts of type enforcement, role-based access control, and multilevel security. FLASK, in turn, was based on DTOS, a Mach-derived ''Distributed Trusted Operating System'', as well as Trusted Mach, a research project from Trusted Information Systems that had an influence on the design and implementation of DTOS. A Linux kernel integrating SELinux enforces mandatory access-control policies that confine user programs and system servers access to files and network resources. Limiting privilege to the minimum required to work reduces or eliminates the ability of these programs and daemons to cause harm if faulty or compromised (via buffer overflows or misconfigurations, for example). This confinement mechanism operates independently of the traditional Linux (discretionary) access control mechanisms. It has no concept of a "root" super-user, and does not share the well-known shortcomings of the traditional Linux security mechanisms (such as a dependence on setuid/setgid binaries). The security of an "unmodified" Linux system (a system without SELinux) depends on the correctness of the kernel, of all the privileged applications, and of each of their configurations. A problem in any one of these areas may allow the compromise of the entire system. In contrast, the security of a "modified" system (based on an SELinux kernel) depends primarily on the correctness of the kernel and its security-policy configuration. While problems with the correctness or configuration of applications may allow the limited compromise of individual user programs and system daemons, they do not necessarily pose a threat to the security of other user programs and system daemons or to the security of the system as a whole. From a purist perspective, SELinux provides a hybrid of concepts and capabilities drawn from mandatory access controls, mandatory integrity controls, role-based access control (RBAC), and type enforcement architecture. Third-party tools enable one to build a variety of security policies. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Security-Enhanced Linux」の詳細全文を読む スポンサード リンク
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