Sudo

Robert Coggeshall and Cliff Spencer wrote the original subsystem around 1980 at the Department of Computer Science at SUNY/Buffalo. ==Design==

Unlike for su, users supply their personal password to (if necessary) rather than that of the superuser or other account. This allows authorized users to exercise altered privileges without compromising the secrecy of the other account's password. Users must be in a certain group to use the command, typically either the wheel or sudo group. After authentication, and if the configuration file permits the user access, the system invokes the requested command. retains the user's invocation rights through a grace period (typically 5 minutes) per pseudo terminal, allowing the user to execute several successive commands as the requested user without having to provide a password again. As a security and auditing feature, may be configured to log each command run. When a user attempts to invoke without being listed in the configuration file, an exception indication is presented to the user indicating that the attempt has been recorded. If configured, the root user will be alerted via mail. By default, an entry is recorded in the system. ==Configuration==

The /etc/sudoers file contains a list of users or user groups with permission to execute a subset of commands while having the privileges of the root user or another specified user. The file can be edited by using the command sudo visudo. Sudo contains several configuration options such as allowing commands to be run as without a password, changing which users can use , and changing the message displayed upon entering an incorrect password. Sudo features an easter egg that can be enabled from the configuration file that will display an insult every time an incorrect password is entered. ==Impact==

In some system distributions, has largely supplanted the default use of a distinct superuser login for administrative tasks, most notably in some Linux distributions as well as Apple's macOS. This allows for more secure logging of admin commands and prevents some exploits. ==RBAC==

In association with SELinux, can be used to transition between roles in role-based access control (RBAC). ==Tools and similar programs==

visudo is a command-line utility that allows editing the sudo configuration file in a fail-safe manner. It prevents multiple simultaneous edits with locks and performs sanity and syntax checks. Sudoedit is a program that symlinks to the sudo binary. When sudo is run via its sudoedit alias, sudo behaves as if the -e flag has been passed and allows users to edit files that require additional privileges to write to. Microsoft released its own tool also called for Windows in February 2024. Its interface is similar to its Unix counterpart by giving the ability to run elevated commands from an unelevated console session, although its implementation is entirely different. The program runas provides comparable functionality in Windows, but it cannot pass current directories, environment variables or long command lines to the child. And while it supports running the child as another user, it does not support simple elevation. Hamilton C shell also includes true and for Windows that can pass all of that state information and start the child either elevated or as another user (or both). Graphical user interfaces exist for sudo – notably gksudo – but are deprecated in Debian and no longer included in Ubuntu. Other user interfaces are not directly built on sudo, but provide similar temporary privilege elevation for administrative purposes, such as pkexec in Unix-like operating systems, User Account Control in Microsoft Windows and Mac OS X Authorization Services. gosu is a tool similar to sudo that is popular in containers where the terminal may not be fully functional or where there are undesirable effects from running sudo in a containerized environment. A rewrite of sudo, called sudo-rs, written in the Rust programming language, became adopted as the default in Ubuntu. ==See also==