session-keyring

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

NAME
       session-keyring - session shared process keyring

DESCRIPTION
       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).  Option-
       ally, PAM may revoke the session keyring on logout.  (In  typical  con-
       figurations, 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  at-
       tached  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  ma-
       nipulating 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"  ses-
              sion  keyring with the name "_ses".  (This function is an inter-
              face 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
       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
       This page is part of release 5.05 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                             2017-09-15                SESSION-KEYRING(7)