session-keyring(7) — Linux manual page

NAME | DESCRIPTION | SEE ALSO | COLOPHON

SESSION-KEYRING(7)      Linux Programmer's Manual     SESSION-KEYRING(7)

NAME         top

       session-keyring - session shared process keyring

DESCRIPTION         top

       The session keyring is a keyring used to anchor keys on behalf of
       a process.  It is typically created by pam_keyinit(8) when a user
       logs in and a link will be added that refers to the
       user-keyring(7).  Optionally, PAM may revoke the session keyring
       on logout.  (In typical configurations, PAM does do this
       revocation.)  The session keyring has the name (description)
       _ses.

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

       From the keyctl(1) utility, '@s' can be used instead of a numeric
       key ID in much the same way.

       A process's session keyring is inherited across clone(2),
       fork(2), and vfork(2).  The session keyring is preserved across
       execve(2), even when the executable is set-user-ID or set-group-
       ID or has capabilities.  The session keyring is destroyed when
       the last process that refers to it exits.

       If a process doesn't have a session keyring when it is accessed,
       then, under certain circumstances, the user-session-keyring(7)
       will be attached as the session keyring and under others a new
       session keyring will be created.  (See user-session-keyring(7)
       for further details.)

   Special operations
       The keyutils library provides the following special operations
       for manipulating session keyrings:

       keyctl_join_session_keyring(3)
              This operation allows the caller to change the session
              keyring that it subscribes to.  The caller can join an
              existing keyring with a specified name (description),
              create a new keyring with a given name, or ask the kernel
              to create a new "anonymous" session keyring with the name
              "_ses".  (This function is an interface to the keyctl(2)
              KEYCTL_JOIN_SESSION_KEYRING operation.)

       keyctl_session_to_parent(3)
              This operation allows the caller to make the parent
              process's session keyring to the same as its own.  For
              this to succeed, the parent process must have identical
              security attributes and must be single threaded.  (This
              function is an interface to the keyctl(2)
              KEYCTL_SESSION_TO_PARENT operation.)

       These operations are also exposed through the keyctl(1) utility
       as:

           keyctl session
           keyctl session - [<prog> <arg1> <arg2> ...]
           keyctl session <name> [<prog> <arg1> <arg2> ...]

       and:

           keyctl new_session

SEE ALSO         top

       keyctl(1), keyctl(3), keyctl_join_session_keyring(3),
       keyctl_session_to_parent(3), keyrings(7), persistent-keyring(7),
       process-keyring(7), thread-keyring(7), user-keyring(7),
       user-session-keyring(7), pam_keyinit(8)

COLOPHON         top

       This page is part of release 5.10 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

Linux                          2020-08-13             SESSION-KEYRING(7)

Pages that refer to this page: add_key(2)keyctl(2)request_key(2)keyctl_join_session_keyring(3)keyctl_session_to_parent(3)systemd.exec(5)keyrings(7)keyutils(7)persistent-keyring(7)process-keyring(7)thread-keyring(7)user-keyring(7)user-session-keyring(7)