In computing, a system call is the programmatic way in which a computer program requests a service from the kernel of the operating system on which it is executed. This may include hardware-related services, creation and execution of new processes, and communication with integral kernel services such as process scheduling. System calls provide an essential interface between a process and the operating system.
A chroot on Unix operating systems is an operation that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name files outside the designated directory tree. The term "chroot" may refer to the chroot(2) system call or the chroot(8) wrapper program. The modified environment is called a chroot jail.
In 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. Whenever a subject attempts to access an object, an authorization rule enforced by the operating system kernel examines these security attributes and decides whether the access can take place. Any operation by any subject on any object is tested against the set of authorization rules to determine if the operation is allowed. A database management system, in its access control mechanism, can also apply mandatory access control; in this case, the objects are tables, views, procedures, etc.
In computer programming and computer security, privilege separation is a technique in which a program is divided into parts which are limited to the specific privileges they require in order to perform a specific task. This is used to mitigate the potential damage of a computer security vulnerability.
In computer security, a sandbox is a security mechanism for separating running programs, usually in an effort to mitigate system failures and/or software vulnerabilities from spreading. It is often used to execute untested or untrusted programs or code, possibly from unverified or untrusted third parties, suppliers, users or websites, without risking harm to the host machine or operating system. A sandbox typically provides a tightly controlled set of resources for guest programs to run in, such as storage and memory scratch space. Network access, the ability to inspect the host system or read from input devices are usually disallowed or heavily restricted.
NDISwrapper is a free software driver wrapper that enables the use of Windows XP network device drivers on Linux operating systems. NDISwrapper works by implementing the Windows kernel and NDIS APIs and dynamically linking Windows network drivers to this implementation. As a result, it only works on systems based on the instruction set architectures supported by Windows, namely IA-32 and x86-64.
In software development, time-of-check to time-of-use is a class of software bugs caused by a race condition involving the checking of the state of a part of a system and the use of the results of that check.
The OpenBSD operating system focuses on security and the development of security features. According to author Michael W. Lucas, OpenBSD "is widely regarded as the most secure operating system available anywhere, under any licensing terms."
Ports collections are the sets of makefiles and patches provided by the BSD-based operating systems, FreeBSD, NetBSD, and OpenBSD, as a simple method of installing software or creating binary packages. They are usually the base of a package management system, with ports handling package creation and additional tools managing package removal, upgrade, and other tasks. In addition to the BSDs, a few Linux distributions have implemented similar infrastructure, including Gentoo's Portage, Arch's Arch Build System (ABS), CRUX's Ports and Void Linux's Templates.
BSD Authentication, otherwise known as BSD Auth, is an authentication framework and software API employed by OpenBSD and accompanying software such as OpenSSH. It originated with BSD/OS, and although the specification and implementation were donated to the FreeBSD project by BSDi, OpenBSD chose to adopt the framework in release 2.9. Pluggable Authentication Modules (PAM) serves a similar purpose on other operating systems such as Linux, FreeBSD and NetBSD.
Wireless network cards for computers require control software to make them function. This is a list of the status of some open-source drivers for 802.11 wireless network cards.
A proprietary device driver is a closed-source device driver published only in binary code. In the context of free and open-source software, a closed-source device driver is referred to as a blob or binary blob. The term usually refers to a closed-source kernel module loaded into the kernel of an open-source operating system, and is sometimes also applied to code running outside the kernel, such as system firmware images, microcode updates, or userland programs. The term blob was first used in database management systems to describe a collection of binary data stored as a single entity.
The XTS-400 is a multilevel secure computer operating system. It is multiuser and multitasking that uses multilevel scheduling in processing data and information. It works in networked environments and supports Gigabit Ethernet and both IPv4 and IPv6.
authbind is an Open-source system utility written by Ian Jackson and is distributed under the GNU General Public License. The authbind software allows a program that would normally require superuser privileges to access privileged network services to run as a non-privileged user. authbind allows the system administrator to permit specific users and groups access to bind to TCP and UDP ports below 1024. Ports 0 - 1023 are normally privileged and reserved for programs that are run as the root user. Allowing regular users limited access to privileged ports helps prevent possible privilege escalation and system compromise if the software happens to contain software bugs or is found to be vulnerable to unknown exploits.
PlayOnLinux is a graphical frontend for the Wine software compatibility layer which allows Linux users to install Windows-based video games, Microsoft Office, Microsoft Internet Explorer, as well as many other applications such as Apple iTunes and Safari.
OpenBSD is a security-focused, free and open-source, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD. According to the website, the OpenBSD project emphasizes "portability, standardization, correctness, proactive security and integrated cryptography."
OpenSSH is a suite of secure networking utilities based on the Secure Shell (SSH) protocol, which provides a secure channel over an unsecured network in a client–server architecture.
OpenSMTPD is a Unix daemon implementing the Simple Mail Transfer Protocol to deliver messages on a local machine or to relay them to other SMTP servers. It was publicly released on 17 March 2013 with version number 5.3, after being in development since late 2008.
LibreSSL is an open-source implementation of the Transport Layer Security (TLS) protocol. The implementation is named after Secure Sockets Layer (SSL), the deprecated predecessor of TLS, for which support was removed in release 2.3.0. The OpenBSD project forked LibreSSL from OpenSSL 1.0.1g in April 2014 as a response to the Heartbleed security vulnerability, with the goals of modernizing the codebase, improving security, and applying development best practices.
doas is a program to execute commands as another user. The system administrator can configure it to give specified users privileges to execute specified commands. It is free and open-source under the ISC license and available in Unix and Unix-like operating systems.
