pam_ssh_agent_auth(8) PAM pam_ssh_agent_auth(8)NAMEpam_ssh_agent_auth - PAM module for granting permissions based on SSH
agent requests
DESCRIPTION
This module provides authentication via ssh-agent. If an ssh-agent
listening at SSH_AUTH_SOCK can successfully authenticate that it has
the secret key for a public key in the specified file, authentication
is granted, otherwise authentication fails.
CONFIGURATION
/etc/pam.d/sudo: auth sufficient pam_ssh_agent_auth.so
file=/etc/security/authorized_keys
/etc/sudoers:
In older versions of sudo (< 1.8.5) it was necessary to set:
Defaults env_keep += "SSH_AUTH_SOCK"
This configuration would permit anyone who has an SSH_AUTH_SOCK that
manages the private key matching a public key in
/etc/security/authorized_keys to execute sudo without having to enter a
password. Note that the ssh-agent listening to SSH_AUTH_SOCK can either
be local, or forwarded.
Unlike NOPASSWD, this still requires an authentication, it's just that
the authentication is provided by ssh-agent, and not password entry.
ARGUMENTS
file=<path to authorized_keys>
Specify the path to the authorized_keys file(s) you would like to
use for authentication. Subject to tilde and % EXPANSIONS (below)
allow_user_owned_authorized_keys_file
A flag which enables authorized_keys files to be owned by the
invoking user, instead of root. This flag is enabled automatically
whenever the expansions %h or ~ are used.
authorized_keys_command=<path to executable>
Specify an external command to run, which should take a single
argument, the username of the person being authenticated, and emit
to its stdout a file in authorized_keys format. This is ideally
suited for use with sssd's sss_ssh_authorizedkeys, for
authenticating users via authorized_keys stored in ldap or other
sssd supported security service.
authorized_keys_command_user=<username>
Specify a user to run the authorized_keys_command as. If this
option is not specified, the authorized_keys_command will be run as
the user being authenticated.
debug
A flag which enables verbose logging
sudo_service_name=<service name you compiled sudo to use>
(when compiled with --enable-sudo-hack)
Specify the service name to use to identify the service "sudo".
When the PAM_SERVICE identifier matches this string, and if
PAM_RUSER is not set, pam_ssh_agent_auth will attempt to identify
the calling user from the environment variable SUDO_USER.
This defaults to "sudo".
EXPANSIONS
~ -- same as in shells, a user's Home directory
Automatically enables allow_user_owned_authorized_keys_file if used
in the context of ~/. If used as ~user/, it would expect the file
to be owned by 'user', unless you explicitly set
allow_user_owned_authorized_keys_file
%h -- User's Home directory
Automatically enables allow_user_owned_authorized_keys_file
%H -- The short-hostname
%u -- Username
%f -- FQDN
EXAMPLES
in /etc/pam.d/sudo
"auth sufficient pam_ssh_agent_auth.so file=~/.ssh/authorized_keys"
The default .ssh/authorized_keys file in a user's home-directory
"auth sufficient pam_ssh_agent_auth.so file=%h/.ssh/authorized_keys"
Same as above.
"auth sufficient pam_ssh_agent_auth.so file=~fred/.ssh/authorized_keys"
If the home-directory of user 'fred' was /home/fred, this would
expand to /home/fred/.ssh/authorized_keys. In this case, we have
not specified allow_user_owned_authorized_keys_file, so this file
must be owned by 'fred'.
"auth sufficient pam_ssh_agent_auth.so
file=/secure/%H/%u/authorized_keys
allow_user_owned_authorized_keys_file"
On a host named foobar.baz.com, and a user named fred, would expand
to /secure/foobar/fred/authorized_keys. In this case, we specified
allow_user_owned_authorized_keys_file, so fred would be able to
manage that authorized_keys file himself.
"auth sufficient pam_ssh_agent_auth.so
file=/secure/%f/%u/authorized_keys"
On a host named foobar.baz.com, and a user named fred, would expand
to /secure/foobar.baz.com/fred/authorized_keys. In this case, we
have not specified allow_user_owned_authorized_keys_file, so this
file must be owned by root.
"auth [success=3 default=ignore] pam_ssh_agent_auth.so
file=~/.ssh/authorized_keys debug"
This pam.d config format allows for more control over how pam
handles success and failure. In this example, we use success=3,
which specifies that when this module succeeds, pam should jump
over the next 3 auth modules and continue from there. This is
useful, for instance, if /etc/pam.d/common-auth is included, and
contains 3 "auth required" or similar module rules that we wish to
skip, but we wish not to skip other auth rules.
For more information, please see http://linux.die.net/man/5/pam.d
COPYRIGHT
Copyright (c) 2008-2014, Jamie Beverly.
And is based on openssh, and the included works by Markus Friedl, Darren Tucker,
Todd C. Miller, Ben Lindstrom, Tim Rice, Damien Miller, and many others.
All rights reserved.
See sources for complete attributions.
Redistribution and use in source and binary forms, with or without modification, are
permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list
of conditions and the following disclaimer in the documentation and/or other materials
provided with the distribution.
THIS SOFTWARE IS PROVIDED BY Jamie Beverly ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL Jamie Beverly OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
v0.10.2 2014-03-31 pam_ssh_agent_auth(8)
