2016-11-01 15:45:23 +00:00
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.\"
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.\" Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
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.\" Written by David Howells (dhowells@redhat.com)
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.\"
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.\" This program is free software; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public Licence
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.\" as published by the Free Software Foundation; either version
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.\" 2 of the Licence, or (at your option) any later version.
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.\"
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.TH "USER KEYRING" 7 "20 Feb 2014" Linux "Kernel key management"
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.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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.SH NAME
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user_keyring \- Per-user keyring
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.SH DESCRIPTION
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The
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.B user keyring
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is a keyring used to anchor keys on behalf of a user. Each UID the kernel
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deals with has its own user keyring. This keyring is associated with the
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record that the kernel maintains for the UID and, once created, is retained as
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long as that record persists. It is shared amongst all processes of that UID.
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.P
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The user keyring is created on demand when a thread requests it. Normally,
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this happens when \fBpam_keyinit\fP is invoked when a user logs in.
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.P
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The user keyring is not searched by default by \fBrequest_key\fP(). When the
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pam_keyinit module creates a session keyring, it adds to it a link to the user
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keyring so that the user keyring will be searched when the session keyring is.
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.P
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A special serial number value, \fBKEY_SPEC_USER_KEYRING\fP, is defined that
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can be used in lieu of the calling process's user keyring's actual serial
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number.
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.P
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From the keyctl utility, '\fB@u\fP' can be used instead of a numeric key ID in
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much the same way.
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.P
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User keyrings are independent of clone(), fork(), vfork(), execve() and exit()
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excepting that the keyring is destroyed when the UID record is destroyed when
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the last process pinning it exits.
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.P
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If it necessary to for a key associated with a user to exist beyond the UID
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record being garbage collected - for example for use by a cron script - then
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the \fBpersistent keyring\fP should be used instead.
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.P
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If a user keyring does not exist when it is accessed, it will be created.
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.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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.SH SEE ALSO
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2016-11-01 17:12:21 +00:00
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.ad l
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.nh
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2016-11-01 15:45:23 +00:00
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.BR keyctl (1),
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.BR keyctl (3),
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.BR keyrings (7),
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2016-11-01 17:12:21 +00:00
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.BR persistent\-keyring (7),
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.BR process\-keyring (7),
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.BR session\-keyring (7),
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.BR thread\-keyring (7),
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.BR user\-session\-keyring (7),
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.BR pam_keyinit (8)
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