Linux kernelThe Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally written in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU operating system, which was written to be a free (libre) replacement for Unix. Linux is provided under the GNU General Public License version 2 only, but it contains files under other compatible licenses.
Linux Security ModulesLinux Security Modules (LSM) is a framework allowing the Linux kernel to support without bias a variety of computer security models. LSM is licensed under the terms of the GNU General Public License and is a standard part of the Linux kernel since Linux 2.6. AppArmor, SELinux, Smack, and TOMOYO Linux are the currently approved security modules in the official kernel. LSM was designed in order to answer all the requirements for successfully implementing a mandatory access control module, while imposing the fewest possible changes to the Linux kernel.
Mandatory access controlIn computer security, mandatory access control (MAC) refers to a type of access control by which the operating system or database constrains the ability of a subject or initiator to access or generally perform some sort of operation on an object or target. In the case of operating systems, a subject is usually a process or thread; objects are constructs such as files, directories, TCP/UDP ports, shared memory segments, IO devices, etc. Subjects and objects each have a set of security attributes.
Security-Enhanced LinuxSecurity-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including 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, and streamlines the amount of software involved with security policy enforcement.
GNU General Public LicenseThe GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and was originally written by the founder of the Free Software Foundation (FSF), Richard Stallman, for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition.
Discretionary access controlIn computer security, discretionary access control (DAC) is a type of access control defined by the Trusted Computer System Evaluation Criteria (TCSEC) as a means of restricting access to objects based on the identity of subjects and/or groups to which they belong. The controls are discretionary in the sense that a subject with a certain access permission is capable of passing that permission (perhaps indirectly) on to any other subject (unless restrained by mandatory access control).
LinuxLinux (ˈlɪnʊks ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the use and importance of GNU software in many distributions, causing some controversy.
