PAM_SSH(8) BSD System Manager's Manual PAM_SSH(8)NAMEpam_ssh — authentication and session management with SSH private keys
SYNOPSIS
[service-name] module-type control-flag pam_ssh [options]
DESCRIPTION
The SSH authentication service module for PAM, pam_ssh provides function‐
ality for two PAM categories: authentication and session management. In
terms of the module-type parameter, they are the “auth” and “session”
features. It also provides null functions for the remaining categories.
SSH Authentication Module
The SSH authentication component provides a function to verify the iden‐
tity of a user (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:
debug syslog(3) debugging information at LOG_DEBUG level.
use_first_pass If the authentication module is not the first in the
stack, and a previous module obtained the user's pass‐
word, 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.
keyfiles Specify the comma-separated list of files in $HOME/.ssh
to check for SSH keys. The default is
“id_dsa,id_rsa,identity”.
nullok Allow empty passphrases.
SSH Session Management Module
The SSH session management component provides functions to initiate
(pam_sm_open_session()) and terminate (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:
debug syslog(3) debugging information at LOG_DEBUG level.
FILES
$HOME/.ssh/identity SSH1/OpenSSH RSA key
$HOME/.ssh/id_dsa OpenSSH DSA key
$HOME/.ssh2/id_rsa_* SSH2 RSA keys
$HOME/.ssh2/id_dsa_* SSH2 DSA keys
SEE ALSOssh-agent(1), syslog(3), pam.conf(5), pam(8)AUTHORS
Andrew J. Korty ⟨ajk@iu.edu⟩ wrote pam_ssh. Dag-Erling Smorgrav wrote
the original OpenPAM support code. Mark R V Murray wrote the original
version of this manual page.
BSD November 26, 2001 BSD
