MAN page from Fedora 21 keyutils-libs-1.5.9-4.fc21.i686.rpm
Section: Kernel key management (7)
Updated: 20 Feb 2014Index
user keyring - Per-user keyring
is a keyring used to anchor keys on behalf of a user. Each UID the kerneldeals with has its own user keyring. This keyring is associated with therecord that the kernel maintains for the UID and, once created, is retained aslong as that record persists. It is shared amongst all processes of that UID.The user keyring is created on demand when a thread requests it. Normally,this happens when pam_keyinit
is invoked when a user logs in.The user keyring is not searched by default by request_key
(). When thepam_keyinit module creates a session keyring, it adds to it a link to the userkeyring so that the user keyring will be searched when the session keyring is.A special serial number value, KEY_SPEC_USER_KEYRING
, is defined thatcan be used in lieu of the calling process's user keyring's actual serialnumber.From the keyctl utility, '@u
' can be used instead of a numeric key ID inmuch the same way.User keyrings are independent of clone(), fork(), vfork(), execve() and exit()excepting that the keyring is destroyed when the UID record is destroyed whenthe last process pinning it exits.If it necessary to for a key associated with a user to exist beyond the UIDrecord being garbage collected - for example for use by a cron script - thenthe persistent keyring
should be used instead.If a user keyring does not exist when it is accessed, it will be created.
- SEE ALSO
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