Polkit

Component of UNIX systems

polkit

KDE Plasma-based front-end

Developer(s)| David Zeuthen, Red Hat
Initial release| 0.3[1]
Stable release|

126[2] / 13 January 2025; 6 months ago (13 January 2025)

Repository|

* github.com/polkit-org/polkit

Written in| C
Operating system| Linux, Unix-like
Type| Privilege authorization
License| LGPL (free software)
Website| github.com/polkit-org/polkit

Polkit (formerly PolicyKit) is a component for controlling system-wide privileges in Unix-like operating systems. It provides an organized way for non-privileged processes to communicate with privileged ones. Polkit allows a level of control of centralized system policy. It is developed and maintained by David Zeuthen from Red Hat and hosted by the freedesktop.org project. It is published as free software under the terms of version 2 of the GNU Lesser General Public License.[3]

Since version 0.105, released in April 2012,[4][5] the name of the project was changed from PolicyKit to polkit to emphasize that the system component was rewritten[6] and that the API had changed, breaking backward compatibility.[7][dubious - discuss]

Fedora became the first distribution to include PolicyKit, and it has since been used in other distributions, including Ubuntu since version 8.04 and openSUSE since version 10.3. Some distributions, like Fedora,[8] have already switched to the rewritten polkit.

It is also possible to use polkit to execute commands with elevated privileges using the command pkexec followed by the command intended to be executed (with root permission).[9] However, it may be preferable to use sudo, as this command provides more flexibility and security, in addition to being easier to configure.[10]

## Implementation

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The `polkitd` daemon implements Polkit functionality.[11]

## Vulnerability

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PwnKitCVE identifier(s)| CVE-2021-4034

|

Date discovered| 18 November 2021; 3 years ago (2021-11-18)
Discoverer| Qualys Research Team
Affected hardware| All architectures
Affected software| Polkit (all versions prior to discovery)
Used by| Default on every major Linux distribution
Website| qualys.com

A memory corruption vulnerability PwnKit (CVE-2021-4034[12]) discovered in the pkexec command (installed on all major Linux distributions) was announced on January 25, 2022.[13][14] The vulnerability dates back to the original distribution from 2009. The vulnerability received a CVSS score of 7.8 ("High severity") reflecting serious factors involved in a possible exploit: unprivileged users can gain full root privileges, regardless of the underlying machine architecture or whether the polkit daemon is running or not.

## See also

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* Free and open-source software portal

* Pluggable authentication module
* Principle of least privilege
* PackageKit
* User Account Control – a similar feature introduced in Windows Vista and still exists in Windows 11

## References

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1. ^ "PolicyKit 0.3". 20 June 2007. Retrieved 17 July 2024.
2. ^ "Release 126 is out". 13 January 2025. Retrieved 26 January 2025.
3. ^ "polkit Git COPYING". David Zeuthen. Retrieved 15 November 2012.
4. ^ "polkit Git NEWS". David Zeuthen. Retrieved 15 November 2012.
5. ^ "Polkit releases". Retrieved 1 September 2018.
6. ^ "Chapter 9. PolicyKit". openSUSE Security Guide. Novell, Inc. and contributors. Archived from the original on 27 August 2012. Retrieved 15 November 2012.
7. ^ "Polkit and KDE: let's make the point of the situation". 22 December 2009. Retrieved 15 November 2012.
8. ^ "Features/PolicyKitOne". Fedora Project Wiki. Retrieved 15 November 2012.
9. ^ "pkexec". polkit Reference Manual. Retrieved 25 May 2013.
10. ^ "When to use pkexec vs. gksu/gksudo?". Retrieved 25 May 2013.
11. ^ Команда разработчиков BLFS (5 September 2017). "4: Bezopasnost'". За пределами проекта "Linux® с нуля". Версия 7.4 [Beyond Linux from scratch] (in Russian). Vol. 1\. Moscow: Litres (published 2017). p. 169\. ISBN 9785457831186. Retrieved 5 September 2017.
12. ^ "CVE listing for CVE-2021-4034". Mitre. Retrieved 25 January 2022.
13. ^ "PwnKit: Local Privilege Escalation Vulnerability Discovered in polkit's pkexec (CVE-2021-4034)". Qualys. 25 January 2022. Retrieved 25 January 2022.
14. ^ "Major Linux PolicyKit security vulnerability uncovered: Pwnkit". ZDNet. 25 January 2022. Retrieved 25 January 2022.

## External links

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Wikimedia Commons has media related to Polkit.

* polkit GitHub repository at github.com
* Documentation at freedesktop.org
* Why polkit explaining polkit's role in a modern system

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