session-keyring (7)

Leading comments

Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
Written by David Howells (dhowells@redhat.com)

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public Licence
as published by the Free Software Foundation; either version
2 of the Licence, or (at your option) any later version.

(The comments found at the beginning of the groff file "man7/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 the pam_keyinit module when a user logs in and a link will be added that refers to the user keyring. A special serial number value, KEY_SPEC_SESSION_KEYRING, is defined that can be used in lieu of the calling process's session keyring's actual serial number. From the keyctl 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(), fork() and vfork() and is retained across execve() - even when the target executable is setuid or setgid. The session keyring will be 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 will be attached as the session keyring and under others a new session keyring will be created.

SPECIAL OPERATIONS

The keyutils library provides a number of special operations for manipulating session keyrings:

keyctl_join_session_keyring()

This operation allows the caller to change their session keyring. The caller can join an existing keyring by name, create a new keyring of the name given or ask the kernel to create a new session keyring with the name "_ses".

keyctl_session_to_parent()

This operation allows the caller to set the parent process's session keyring to the same as their own. For this to succeed, the parent process must have identical security attributes and must be single threaded. These operations are also exposed through the keyctl 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),
pam_keyinit(8),
keyrings(7),
thread-keyring(7),
process-keyring(7),
user-keyring(7),
user-session-keyring(7)
persistent-keyring(7)