keyutils (7) - Linux Manuals

keyutils: in-kernel key management utilities


keyutils - in-kernel key management utilities


The keyutils package is a library and a set of utilities for accessing the kernel keyrings facility.

A header file is supplied to provide the definitions and declarations required to access the library:

#include <keyutils.h>

To link with the library, the following:


should be specified to the linker.

Three system calls are provided:

Supply a new key to the kernel.
Find an existing key for use, or, optionally, create one if one does not exist.
Control a key in various ways. The library provides a variety of wrappers around this system call and those should be used rather than calling it directly.

See the add_key(2), request_key(2), and keyctl(2) manual pages for more information.

The keyctl() wrappers are listed on the keyctl(3) manual page.


A program is provided to interact with the kernel facility by a number of subcommands, e.g.:

keyctl add user foo bar @s

See the keyctl(1) manual page for information on that.

The kernel has the ability to upcall to userspace to fabricate new keys. This can be triggered by request_key(), but userspace is better off using add_key() instead if it possibly can.

The upcalling mechanism is usually routed via the request-key(8) program. What this does with any particular key is configurable in:


See the request-key.conf(5) and the request-key(8) manual pages for more information.