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NAME | DESCRIPTION | SEE ALSO | COLOPHON |
SESSION-KEYRING(7) Linux Programmer's Manual SESSION-KEYRING(7)
session-keyring - session shared process keyring
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
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)
This page is part of release 4.12 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 2017-03-13 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), keyrings(7), keyutils(7), persistent-keyring(7), process-keyring(7), thread-keyring(7), user-keyring(7), user-session-keyring(7)