.\" Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
.\" Written by David Howells (dhowells@redhat.com)
.\"
.\" %%%LICENSE_START(GPLv2+_SW_ONEPARA)
.\" This program is free software; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License
.\" as published by the Free Software Foundation; either version
.\" 2 of the License, or (at your option) any later version.
.\" %%%LICENSE_END
.\"
.\" FIXME Document KEYCTL_REJECT (new in 2.6.39)
.\"		commit fdd1b94581782a2ddf9124414e5b7a5f48ce2f9c
.\"		Author: David Howells <dhowells@redhat.com>
.\"		Documentation/security/keys.txt
.\" FIXME Document KEYCTL_INSTANTIATE_IOV (new in 2.6.39)
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.\" FIXME Document KEYCTL_INVALIDATE (new in 3.5)
.\"		commit fd75815f727f157a05f4c96b5294a4617c0557da
.\"		Author: David Howells <dhowells@redhat.com>
.\"		Documentation/security/keys.txt
.\" FIXME Document KEYCTL_GET_PERSISTENT (new in 3.13)
.\"		commit f36f8c75ae2e7d4da34f4c908cebdb4aa42c977e
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.TH KEYCTL 2 2014-01-22 Linux "Linux Key Management Calls"
.SH NAME
keyctl \- manipulate the kernel's key management facility
.SH SYNOPSIS
.nf
.B #include <keyutils.h>
.sp
.BI "long keyctl(int " cmd ", ...);"
.fi
.SH DESCRIPTION
.BR keyctl ()
has a number of functions available:
.TP
.B KEYCTL_GET_KEYRING_ID
Ask for a keyring's ID.
.TP
.B KEYCTL_JOIN_SESSION_KEYRING
Join or start named session keyring.
.TP
.B KEYCTL_UPDATE
Update a key.
.TP
.B KEYCTL_REVOKE
Revoke a key.
.TP
.B KEYCTL_CHOWN
Set ownership of a key.
.TP
.B KEYCTL_SETPERM
Set perms on a key.
.TP
.B KEYCTL_DESCRIBE
Describe a key.
.TP
.B KEYCTL_CLEAR
Clear contents of a keyring.
.TP
.B KEYCTL_LINK
Link a key into a keyring.
.TP
.B KEYCTL_UNLINK
Unlink a key from a keyring.
.TP
.B KEYCTL_SEARCH
Search for a key in a keyring.
.TP
.B KEYCTL_READ
Read a key or keyring's contents.
.TP
.B KEYCTL_INSTANTIATE
Instantiate a partially constructed key.
.TP
.B KEYCTL_NEGATE
Negate a partially constructed key.
.TP
.B KEYCTL_SET_REQKEY_KEYRING
Set default request-key keyring.
.TP
.B KEYCTL_SET_TIMEOUT
Set timeout on a key.
.TP
.B KEYCTL_ASSUME_AUTHORITY
Assume authority to instantiate key.
.P
These are wrapped by
.B libkeyutils
into individual functions to permit compiler the compiler to check types.
See the
.B See Also
section at the bottom.
.SH RETURN VALUE
On success
.BR keyctl ()
returns the serial number of the key it found.
On error, the value \-1
will be returned and errno will have been set to an appropriate error.
.SH ERRORS
.TP
.B EACCES
A key operation wasn't permitted.
.TP
.B EDQUOT
The key quota for the caller's user would be exceeded by creating a key or
linking it to the keyring.
.TP
.B EKEYEXPIRED
An expired key was found or specified.
.TP
.B EKEYREJECTED
A rejected key was found or specified.
.TP
.B EKEYREVOKED
A revoked key was found or specified.
.TP
.B ENOKEY
No matching key was found or an invalid key was specified.
.SH LINKING
Although this is a Linux system call, it is not present in
.I libc
but can be found rather in
.IR libkeyutils .
When linking,
.B -lkeyutils
should be specified to the linker.
.SH SEE ALSO
.ad l
.nh
.BR keyctl (1),
.BR add_key (2),
.BR request_key (2),
.BR keyctl_set_timeout (3),
.BR keyctl_chown (3),
.BR keyctl_clear (3),
.BR keyctl_describe (3),
.BR keyctl_describe_alloc (3),
.BR keyctl_get_keyring_ID (3),
.BR keyctl_instantiate (3),
.BR keyctl_join_session_keyring (3),
.BR keyctl_link (3),
.BR keyctl_negate (3),
.BR keyctl_revoke (3),
.BR keyctl_search (3),
.BR keyctl_setperm (3),
.BR keyctl_set_reqkey_keyring (3),
.BR keyctl_set_timeout (3),
.BR keyctl_read (3),
.BR keyctl_read_alloc (3),
.BR keyctl_unlink (3),
.BR keyctl_update (3),
.BR request-key (8)

The kernel source file
.IR Documentation/security/keys.txt .
.SH COLOPHON
This page is part of release 3.74 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%http://www.kernel.org/doc/man\-pages/.