session-keyring(7) - Linux manual page (original) (raw)

user-se...keyring(7) Miscellaneous Information Manual_user-se...keyring_(7)

NAME top

   user-session-keyring - per-user default session keyring

DESCRIPTION top

   The user session keyring is a keyring used to anchor keys on
   behalf of a user.  Each UID the kernel deals with has its own user
   session keyring that is shared by all processes with that UID.
   The user session keyring has a name (description) of the form
   __uidses.<UID>_ where _<UID>_ is the user ID of the corresponding
   user.

   The user session keyring is associated with the record that the
   kernel maintains for the UID.  It comes into existence upon the
   first attempt to access either the user session keyring, the
   [user-keyring(7)](../man7/user-keyring.7.html), or the [session-keyring(7)](../man7/session-keyring.7.html).  The keyring remains
   pinned in existence so long as there are processes running with
   that real UID or files opened by those processes remain open.
   (The keyring can also be pinned indefinitely by linking it into
   another keyring.)

   The user session keyring is created on demand when a thread
   requests it or when a thread asks for its [session-keyring(7)](../man7/session-keyring.7.html) and
   that keyring doesn't exist.  In the latter case, a user session
   keyring will be created and, if the session keyring wasn't to be
   created, the user session keyring will be set as the process's
   actual session keyring.

   The user session keyring is searched by [request_key(2)](../man2/request%5Fkey.2.html) if the
   actual session keyring does not exist and is ignored otherwise.

   A special serial number value, **KEY_SPEC_USER_SESSION_KEYRING**, is
   defined that can be used in lieu of the actual serial number of
   the calling process's user session keyring.

   From the [keyctl(1)](../man1/keyctl.1.html) utility, '**@us**' can be used instead of a numeric
   key ID in much the same way.

   User session keyrings are independent of [clone(2)](../man2/clone.2.html), [fork(2)](../man2/fork.2.html),
   [vfork(2)](../man2/vfork.2.html), [execve(2)](../man2/execve.2.html), and [_exit(2)](../man2/%5Fexit.2.html) excepting that the keyring is
   destroyed when the UID record is destroyed when the last process
   pinning it exits.

   If a user session keyring does not exist when it is accessed, it
   will be created.

   Rather than relying on the user session keyring, it is strongly
   recommended—especially if the process is running as root—that a
   [session-keyring(7)](../man7/session-keyring.7.html) be set explicitly, for example by
   [pam_keyinit(8)](../man8/pam%5Fkeyinit.8.html).

NOTES top

   The user session keyring was added to support situations where a
   process doesn't have a session keyring, perhaps because it was
   created via a pathway that didn't involve PAM (e.g., perhaps it
   was a daemon started by **inetd**(8)).  In such a scenario, the user
   session keyring acts as a substitute for the [session-keyring(7)](../man7/session-keyring.7.html).

SEE ALSO top

   [keyctl(1)](../man1/keyctl.1.html), [keyctl(3)](../man3/keyctl.3.html), [keyrings(7)](../man7/keyrings.7.html), [persistent-keyring(7)](../man7/persistent-keyring.7.html),
   [process-keyring(7)](../man7/process-keyring.7.html), [session-keyring(7)](../man7/session-keyring.7.html), [thread-keyring(7)](../man7/thread-keyring.7.html),
   [user-keyring(7)](../man7/user-keyring.7.html)

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Linux man-pages 6.10 2024-05-02 user-se...keyring(7)

Pages that refer to this page:add_key(2), keyctl(2), KEYCTL_GET_KEYRING_ID(2const), KEYCTL_SET_REQKEY_KEYRING(2const), request_key(2), keyctl_join_session_keyring(3), keyctl_session_to_parent(3), keyrings(7), keyutils(7), persistent-keyring(7), process-keyring(7), session-keyring(7), thread-keyring(7), user-keyring(7), pam_keyinit(8)