The
SSH
authentication service module for PAM,
provides functionality for two PAM categories:
authentication
and session management.
In terms of the
module-type
parameter, they are the
``auth
''
and
``session
''
features.
SSH Authentication Module
The
SSH
authentication component
provides a function to verify the identity of a user
(Fn pam_sm_authenticate
)
by prompting the user for a passphrase and verifying that it can
decrypt the target user's SSH key using that passphrase.
The following options may be passed to the authentication module:
use_first_pass
If the authentication module
is not the first in the stack,
and a previous module
obtained the user's password,
that password is used
to authenticate the user.
If this fails,
the authentication module returns failure
without prompting the user for a password.
This option has no effect
if the authentication module
is the first in the stack,
or if no previous modules
obtained the user's password.
try_first_pass
This option is similar to the
use_first_pass
option,
except that if the previously obtained password fails,
the user is prompted for another password.
nullok
Normally, keys with no passphrase are ignored for authentication
purposes.
If this option is set, keys with no passphrase will be taken into
consideration, allowing the user to log in with a blank password.
SSH Session Management Module
The
SSH
session management component
provides functions to initiate
(Fn pam_sm_open_session
)
and terminate
(Fn pam_sm_close_session
)
sessions.
The
pam_sm_open_session ();
function starts an SSH agent,
passing it any private keys it decrypted
during the authentication phase,
and sets the environment variables
the agent specifies.
The
pam_sm_close_session ();
function kills the previously started SSH agent
by sending it a
SIGTERM
The following options may be passed to the session management module:
want_agent
Start an agent even if no keys were decrypted during the
authentication phase.
The
module was originally written by
An -nosplit
An Andrew J. Korty Aq [email protected] .
The current implementation was developed for the
Fx Project by
ThinkSec AS and NAI Labs, the Security Research Division of Network
Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
(``CBOSS''
)
as part of the DARPA CHATS research program.
This manual page was written by
An Mark R V Murray Aq [email protected] .
