Provided by: keyutils_1.5.9-8ubuntu1_amd64 bug


       user-session-keyring - Per-user default session keyring


       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.  This keyring is  associated  with
       the record that the kernel maintains for the UID and, once created, is retained as long as
       that record persists.  It is shared amongst all processes of that UID.

       The user session keyring is created on demand when a thread requests it or when  a  thread
       asks  for  its session keyring and that 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() 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 calling process's user session keyring's actual serial number.

       From  the  keyctl  utility, '@us' can be used instead of a numeric key ID in much the same

       User session keyrings are independent of clone(), fork(),  vfork(),  execve()  and  exit()
       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.

       It is strongly recommended that a session  keyring  be  set  explicitly,  for  example  by
       pam_keyinit,  rather  than relying on the user session keyring - particularly if a process
       is running as root.