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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
     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"  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